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
306 config PGTABLE_LEVELS
312 source "init/Kconfig"
313 source "kernel/Kconfig.freezer"
315 menu "Processor type and features"
318 bool "DMA memory allocation support" if EXPERT
321 DMA memory allocation support allows devices with less than 32-bit
322 addressing to allocate within the first 16MB of address space.
323 Disable if no such devices will be used.
328 bool "Symmetric multi-processing support"
330 This enables support for systems with more than one CPU. If you have
331 a system with only one CPU, say N. If you have a system with more
334 If you say N here, the kernel will run on uni- and multiprocessor
335 machines, but will use only one CPU of a multiprocessor machine. If
336 you say Y here, the kernel will run on many, but not all,
337 uniprocessor machines. On a uniprocessor machine, the kernel
338 will run faster if you say N here.
340 Note that if you say Y here and choose architecture "586" or
341 "Pentium" under "Processor family", the kernel will not work on 486
342 architectures. Similarly, multiprocessor kernels for the "PPro"
343 architecture may not work on all Pentium based boards.
345 People using multiprocessor machines who say Y here should also say
346 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
347 Management" code will be disabled if you say Y here.
349 See also <file:Documentation/x86/i386/IO-APIC.txt>,
350 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
351 <http://www.tldp.org/docs.html#howto>.
353 If you don't know what to do here, say N.
355 config X86_FEATURE_NAMES
356 bool "Processor feature human-readable names" if EMBEDDED
359 This option compiles in a table of x86 feature bits and corresponding
360 names. This is required to support /proc/cpuinfo and a few kernel
361 messages. You can disable this to save space, at the expense of
362 making those few kernel messages show numeric feature bits instead.
366 config X86_FAST_FEATURE_TESTS
367 bool "Fast CPU feature tests" if EMBEDDED
370 Some fast-paths in the kernel depend on the capabilities of the CPU.
371 Say Y here for the kernel to patch in the appropriate code at runtime
372 based on the capabilities of the CPU. The infrastructure for patching
373 code at runtime takes up some additional space; space-constrained
374 embedded systems may wish to say N here to produce smaller, slightly
378 bool "Support x2apic"
379 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
381 This enables x2apic support on CPUs that have this feature.
383 This allows 32-bit apic IDs (so it can support very large systems),
384 and accesses the local apic via MSRs not via mmio.
386 If you don't know what to do here, say N.
389 bool "Enable MPS table" if ACPI || SFI
391 depends on X86_LOCAL_APIC
393 For old smp systems that do not have proper acpi support. Newer systems
394 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
397 bool "Support for big SMP systems with more than 8 CPUs"
398 depends on X86_32 && SMP
400 This option is needed for the systems that have more than 8 CPUs
404 depends on X86_GOLDFISH
407 config X86_EXTENDED_PLATFORM
408 bool "Support for extended (non-PC) x86 platforms"
411 If you disable this option then the kernel will only support
412 standard PC platforms. (which covers the vast majority of
415 If you enable this option then you'll be able to select support
416 for the following (non-PC) 32 bit x86 platforms:
417 Goldfish (Android emulator)
420 SGI 320/540 (Visual Workstation)
421 STA2X11-based (e.g. Northville)
422 Moorestown MID devices
424 If you have one of these systems, or if you want to build a
425 generic distribution kernel, say Y here - otherwise say N.
429 config X86_EXTENDED_PLATFORM
430 bool "Support for extended (non-PC) x86 platforms"
433 If you disable this option then the kernel will only support
434 standard PC platforms. (which covers the vast majority of
437 If you enable this option then you'll be able to select support
438 for the following (non-PC) 64 bit x86 platforms:
443 If you have one of these systems, or if you want to build a
444 generic distribution kernel, say Y here - otherwise say N.
446 # This is an alphabetically sorted list of 64 bit extended platforms
447 # Please maintain the alphabetic order if and when there are additions
449 bool "Numascale NumaChip"
451 depends on X86_EXTENDED_PLATFORM
454 depends on X86_X2APIC
455 depends on PCI_MMCONFIG
457 Adds support for Numascale NumaChip large-SMP systems. Needed to
458 enable more than ~168 cores.
459 If you don't have one of these, you should say N here.
463 select HYPERVISOR_GUEST
465 depends on X86_64 && PCI
466 depends on X86_EXTENDED_PLATFORM
469 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
470 supposed to run on these EM64T-based machines. Only choose this option
471 if you have one of these machines.
474 bool "SGI Ultraviolet"
476 depends on X86_EXTENDED_PLATFORM
478 depends on X86_X2APIC
481 This option is needed in order to support SGI Ultraviolet systems.
482 If you don't have one of these, you should say N here.
484 # Following is an alphabetically sorted list of 32 bit extended platforms
485 # Please maintain the alphabetic order if and when there are additions
488 bool "Goldfish (Virtual Platform)"
489 depends on X86_EXTENDED_PLATFORM
491 Enable support for the Goldfish virtual platform used primarily
492 for Android development. Unless you are building for the Android
493 Goldfish emulator say N here.
496 bool "CE4100 TV platform"
498 depends on PCI_GODIRECT
499 depends on X86_IO_APIC
501 depends on X86_EXTENDED_PLATFORM
502 select X86_REBOOTFIXUPS
504 select OF_EARLY_FLATTREE
506 Select for the Intel CE media processor (CE4100) SOC.
507 This option compiles in support for the CE4100 SOC for settop
508 boxes and media devices.
511 bool "Intel MID platform support"
513 depends on X86_EXTENDED_PLATFORM
514 depends on X86_PLATFORM_DEVICES
517 depends on X86_IO_APIC
523 select MFD_INTEL_MSIC
525 Select to build a kernel capable of supporting Intel MID (Mobile
526 Internet Device) platform systems which do not have the PCI legacy
527 interfaces. If you are building for a PC class system say N here.
529 Intel MID platforms are based on an Intel processor and chipset which
530 consume less power than most of the x86 derivatives.
532 config X86_INTEL_QUARK
533 bool "Intel Quark platform support"
535 depends on X86_EXTENDED_PLATFORM
536 depends on X86_PLATFORM_DEVICES
540 depends on X86_IO_APIC
545 Select to include support for Quark X1000 SoC.
546 Say Y here if you have a Quark based system such as the Arduino
547 compatible Intel Galileo.
549 config X86_INTEL_LPSS
550 bool "Intel Low Power Subsystem Support"
551 depends on X86 && ACPI
556 Select to build support for Intel Low Power Subsystem such as
557 found on Intel Lynxpoint PCH. Selecting this option enables
558 things like clock tree (common clock framework) and pincontrol
559 which are needed by the LPSS peripheral drivers.
561 config X86_AMD_PLATFORM_DEVICE
562 bool "AMD ACPI2Platform devices support"
567 Select to interpret AMD specific ACPI device to platform device
568 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
569 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
570 implemented under PINCTRL subsystem.
573 tristate "Intel SoC IOSF Sideband support for SoC platforms"
576 This option enables sideband register access support for Intel SoC
577 platforms. On these platforms the IOSF sideband is used in lieu of
578 MSR's for some register accesses, mostly but not limited to thermal
579 and power. Drivers may query the availability of this device to
580 determine if they need the sideband in order to work on these
581 platforms. The sideband is available on the following SoC products.
582 This list is not meant to be exclusive.
587 You should say Y if you are running a kernel on one of these SoC's.
589 config IOSF_MBI_DEBUG
590 bool "Enable IOSF sideband access through debugfs"
591 depends on IOSF_MBI && DEBUG_FS
593 Select this option to expose the IOSF sideband access registers (MCR,
594 MDR, MCRX) through debugfs to write and read register information from
595 different units on the SoC. This is most useful for obtaining device
596 state information for debug and analysis. As this is a general access
597 mechanism, users of this option would have specific knowledge of the
598 device they want to access.
600 If you don't require the option or are in doubt, say N.
603 bool "RDC R-321x SoC"
605 depends on X86_EXTENDED_PLATFORM
607 select X86_REBOOTFIXUPS
609 This option is needed for RDC R-321x system-on-chip, also known
611 If you don't have one of these chips, you should say N here.
613 config X86_32_NON_STANDARD
614 bool "Support non-standard 32-bit SMP architectures"
615 depends on X86_32 && SMP
616 depends on X86_EXTENDED_PLATFORM
618 This option compiles in the bigsmp and STA2X11 default
619 subarchitectures. It is intended for a generic binary
620 kernel. If you select them all, kernel will probe it one by
621 one and will fallback to default.
623 # Alphabetically sorted list of Non standard 32 bit platforms
625 config X86_SUPPORTS_MEMORY_FAILURE
627 # MCE code calls memory_failure():
629 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
630 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
631 depends on X86_64 || !SPARSEMEM
632 select ARCH_SUPPORTS_MEMORY_FAILURE
635 bool "STA2X11 Companion Chip Support"
636 depends on X86_32_NON_STANDARD && PCI
637 select X86_DEV_DMA_OPS
641 select ARCH_REQUIRE_GPIOLIB
644 This adds support for boards based on the STA2X11 IO-Hub,
645 a.k.a. "ConneXt". The chip is used in place of the standard
646 PC chipset, so all "standard" peripherals are missing. If this
647 option is selected the kernel will still be able to boot on
648 standard PC machines.
651 tristate "Eurobraille/Iris poweroff module"
654 The Iris machines from EuroBraille do not have APM or ACPI support
655 to shut themselves down properly. A special I/O sequence is
656 needed to do so, which is what this module does at
659 This is only for Iris machines from EuroBraille.
663 config SCHED_OMIT_FRAME_POINTER
665 prompt "Single-depth WCHAN output"
668 Calculate simpler /proc/<PID>/wchan values. If this option
669 is disabled then wchan values will recurse back to the
670 caller function. This provides more accurate wchan values,
671 at the expense of slightly more scheduling overhead.
673 If in doubt, say "Y".
675 menuconfig HYPERVISOR_GUEST
676 bool "Linux guest support"
678 Say Y here to enable options for running Linux under various hyper-
679 visors. This option enables basic hypervisor detection and platform
682 If you say N, all options in this submenu will be skipped and
683 disabled, and Linux guest support won't be built in.
688 bool "Enable paravirtualization code"
690 This changes the kernel so it can modify itself when it is run
691 under a hypervisor, potentially improving performance significantly
692 over full virtualization. However, when run without a hypervisor
693 the kernel is theoretically slower and slightly larger.
695 config PARAVIRT_DEBUG
696 bool "paravirt-ops debugging"
697 depends on PARAVIRT && DEBUG_KERNEL
699 Enable to debug paravirt_ops internals. Specifically, BUG if
700 a paravirt_op is missing when it is called.
702 config PARAVIRT_SPINLOCKS
703 bool "Paravirtualization layer for spinlocks"
704 depends on PARAVIRT && SMP
705 select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS
707 Paravirtualized spinlocks allow a pvops backend to replace the
708 spinlock implementation with something virtualization-friendly
709 (for example, block the virtual CPU rather than spinning).
711 It has a minimal impact on native kernels and gives a nice performance
712 benefit on paravirtualized KVM / Xen kernels.
714 If you are unsure how to answer this question, answer Y.
716 config QUEUED_LOCK_STAT
717 bool "Paravirt queued spinlock statistics"
718 depends on PARAVIRT_SPINLOCKS && DEBUG_FS && QUEUED_SPINLOCKS
720 Enable the collection of statistical data on the slowpath
721 behavior of paravirtualized queued spinlocks and report
724 source "arch/x86/xen/Kconfig"
727 bool "KVM Guest support (including kvmclock)"
729 select PARAVIRT_CLOCK
732 This option enables various optimizations for running under the KVM
733 hypervisor. It includes a paravirtualized clock, so that instead
734 of relying on a PIT (or probably other) emulation by the
735 underlying device model, the host provides the guest with
736 timing infrastructure such as time of day, and system time
739 bool "Enable debug information for KVM Guests in debugfs"
740 depends on KVM_GUEST && DEBUG_FS
743 This option enables collection of various statistics for KVM guest.
744 Statistics are displayed in debugfs filesystem. Enabling this option
745 may incur significant overhead.
747 source "arch/x86/lguest/Kconfig"
749 config PARAVIRT_TIME_ACCOUNTING
750 bool "Paravirtual steal time accounting"
754 Select this option to enable fine granularity task steal time
755 accounting. Time spent executing other tasks in parallel with
756 the current vCPU is discounted from the vCPU power. To account for
757 that, there can be a small performance impact.
759 If in doubt, say N here.
761 config PARAVIRT_CLOCK
764 endif #HYPERVISOR_GUEST
769 source "arch/x86/Kconfig.cpu"
773 prompt "HPET Timer Support" if X86_32
775 Use the IA-PC HPET (High Precision Event Timer) to manage
776 time in preference to the PIT and RTC, if a HPET is
778 HPET is the next generation timer replacing legacy 8254s.
779 The HPET provides a stable time base on SMP
780 systems, unlike the TSC, but it is more expensive to access,
781 as it is off-chip. You can find the HPET spec at
782 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
784 You can safely choose Y here. However, HPET will only be
785 activated if the platform and the BIOS support this feature.
786 Otherwise the 8254 will be used for timing services.
788 Choose N to continue using the legacy 8254 timer.
790 config HPET_EMULATE_RTC
792 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
795 def_bool y if X86_INTEL_MID
796 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
798 depends on X86_INTEL_MID && SFI
800 APB timer is the replacement for 8254, HPET on X86 MID platforms.
801 The APBT provides a stable time base on SMP
802 systems, unlike the TSC, but it is more expensive to access,
803 as it is off-chip. APB timers are always running regardless of CPU
804 C states, they are used as per CPU clockevent device when possible.
806 # Mark as expert because too many people got it wrong.
807 # The code disables itself when not needed.
810 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
811 bool "Enable DMI scanning" if EXPERT
813 Enabled scanning of DMI to identify machine quirks. Say Y
814 here unless you have verified that your setup is not
815 affected by entries in the DMI blacklist. Required by PNP
819 bool "Old AMD GART IOMMU support"
821 depends on X86_64 && PCI && AMD_NB
823 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
824 GART based hardware IOMMUs.
826 The GART supports full DMA access for devices with 32-bit access
827 limitations, on systems with more than 3 GB. This is usually needed
828 for USB, sound, many IDE/SATA chipsets and some other devices.
830 Newer systems typically have a modern AMD IOMMU, supported via
831 the CONFIG_AMD_IOMMU=y config option.
833 In normal configurations this driver is only active when needed:
834 there's more than 3 GB of memory and the system contains a
835 32-bit limited device.
840 bool "IBM Calgary IOMMU support"
842 depends on X86_64 && PCI
844 Support for hardware IOMMUs in IBM's xSeries x366 and x460
845 systems. Needed to run systems with more than 3GB of memory
846 properly with 32-bit PCI devices that do not support DAC
847 (Double Address Cycle). Calgary also supports bus level
848 isolation, where all DMAs pass through the IOMMU. This
849 prevents them from going anywhere except their intended
850 destination. This catches hard-to-find kernel bugs and
851 mis-behaving drivers and devices that do not use the DMA-API
852 properly to set up their DMA buffers. The IOMMU can be
853 turned off at boot time with the iommu=off parameter.
854 Normally the kernel will make the right choice by itself.
857 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
859 prompt "Should Calgary be enabled by default?"
860 depends on CALGARY_IOMMU
862 Should Calgary be enabled by default? if you choose 'y', Calgary
863 will be used (if it exists). If you choose 'n', Calgary will not be
864 used even if it exists. If you choose 'n' and would like to use
865 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
868 # need this always selected by IOMMU for the VIA workaround
872 Support for software bounce buffers used on x86-64 systems
873 which don't have a hardware IOMMU. Using this PCI devices
874 which can only access 32-bits of memory can be used on systems
875 with more than 3 GB of memory.
880 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
883 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
884 depends on X86_64 && SMP && DEBUG_KERNEL
885 select CPUMASK_OFFSTACK
887 Enable maximum number of CPUS and NUMA Nodes for this architecture.
891 int "Maximum number of CPUs" if SMP && !MAXSMP
892 range 2 8 if SMP && X86_32 && !X86_BIGSMP
893 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
894 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
896 default "8192" if MAXSMP
897 default "32" if SMP && X86_BIGSMP
898 default "8" if SMP && X86_32
901 This allows you to specify the maximum number of CPUs which this
902 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
903 supported value is 8192, otherwise the maximum value is 512. The
904 minimum value which makes sense is 2.
906 This is purely to save memory - each supported CPU adds
907 approximately eight kilobytes to the kernel image.
910 bool "SMT (Hyperthreading) scheduler support"
913 SMT scheduler support improves the CPU scheduler's decision making
914 when dealing with Intel Pentium 4 chips with HyperThreading at a
915 cost of slightly increased overhead in some places. If unsure say
920 prompt "Multi-core scheduler support"
923 Multi-core scheduler support improves the CPU scheduler's decision
924 making when dealing with multi-core CPU chips at a cost of slightly
925 increased overhead in some places. If unsure say N here.
927 source "kernel/Kconfig.preempt"
931 depends on !SMP && X86_LOCAL_APIC
934 bool "Local APIC support on uniprocessors" if !PCI_MSI
936 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
938 A local APIC (Advanced Programmable Interrupt Controller) is an
939 integrated interrupt controller in the CPU. If you have a single-CPU
940 system which has a processor with a local APIC, you can say Y here to
941 enable and use it. If you say Y here even though your machine doesn't
942 have a local APIC, then the kernel will still run with no slowdown at
943 all. The local APIC supports CPU-generated self-interrupts (timer,
944 performance counters), and the NMI watchdog which detects hard
948 bool "IO-APIC support on uniprocessors"
949 depends on X86_UP_APIC
951 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
952 SMP-capable replacement for PC-style interrupt controllers. Most
953 SMP systems and many recent uniprocessor systems have one.
955 If you have a single-CPU system with an IO-APIC, you can say Y here
956 to use it. If you say Y here even though your machine doesn't have
957 an IO-APIC, then the kernel will still run with no slowdown at all.
959 config X86_LOCAL_APIC
961 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
962 select IRQ_DOMAIN_HIERARCHY
963 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
967 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
969 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
970 bool "Reroute for broken boot IRQs"
971 depends on X86_IO_APIC
973 This option enables a workaround that fixes a source of
974 spurious interrupts. This is recommended when threaded
975 interrupt handling is used on systems where the generation of
976 superfluous "boot interrupts" cannot be disabled.
978 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
979 entry in the chipset's IO-APIC is masked (as, e.g. the RT
980 kernel does during interrupt handling). On chipsets where this
981 boot IRQ generation cannot be disabled, this workaround keeps
982 the original IRQ line masked so that only the equivalent "boot
983 IRQ" is delivered to the CPUs. The workaround also tells the
984 kernel to set up the IRQ handler on the boot IRQ line. In this
985 way only one interrupt is delivered to the kernel. Otherwise
986 the spurious second interrupt may cause the kernel to bring
987 down (vital) interrupt lines.
989 Only affects "broken" chipsets. Interrupt sharing may be
990 increased on these systems.
993 bool "Machine Check / overheating reporting"
994 select GENERIC_ALLOCATOR
997 Machine Check support allows the processor to notify the
998 kernel if it detects a problem (e.g. overheating, data corruption).
999 The action the kernel takes depends on the severity of the problem,
1000 ranging from warning messages to halting the machine.
1002 config X86_MCE_INTEL
1004 prompt "Intel MCE features"
1005 depends on X86_MCE && X86_LOCAL_APIC
1007 Additional support for intel specific MCE features such as
1008 the thermal monitor.
1012 prompt "AMD MCE features"
1013 depends on X86_MCE && X86_LOCAL_APIC
1015 Additional support for AMD specific MCE features such as
1016 the DRAM Error Threshold.
1018 config X86_ANCIENT_MCE
1019 bool "Support for old Pentium 5 / WinChip machine checks"
1020 depends on X86_32 && X86_MCE
1022 Include support for machine check handling on old Pentium 5 or WinChip
1023 systems. These typically need to be enabled explicitly on the command
1026 config X86_MCE_THRESHOLD
1027 depends on X86_MCE_AMD || X86_MCE_INTEL
1030 config X86_MCE_INJECT
1032 tristate "Machine check injector support"
1034 Provide support for injecting machine checks for testing purposes.
1035 If you don't know what a machine check is and you don't do kernel
1036 QA it is safe to say n.
1038 config X86_THERMAL_VECTOR
1040 depends on X86_MCE_INTEL
1042 config X86_LEGACY_VM86
1043 bool "Legacy VM86 support"
1047 This option allows user programs to put the CPU into V8086
1048 mode, which is an 80286-era approximation of 16-bit real mode.
1050 Some very old versions of X and/or vbetool require this option
1051 for user mode setting. Similarly, DOSEMU will use it if
1052 available to accelerate real mode DOS programs. However, any
1053 recent version of DOSEMU, X, or vbetool should be fully
1054 functional even without kernel VM86 support, as they will all
1055 fall back to software emulation. Nevertheless, if you are using
1056 a 16-bit DOS program where 16-bit performance matters, vm86
1057 mode might be faster than emulation and you might want to
1060 Note that any app that works on a 64-bit kernel is unlikely to
1061 need this option, as 64-bit kernels don't, and can't, support
1062 V8086 mode. This option is also unrelated to 16-bit protected
1063 mode and is not needed to run most 16-bit programs under Wine.
1065 Enabling this option increases the complexity of the kernel
1066 and slows down exception handling a tiny bit.
1068 If unsure, say N here.
1072 default X86_LEGACY_VM86
1075 bool "Enable support for 16-bit segments" if EXPERT
1077 depends on MODIFY_LDT_SYSCALL
1079 This option is required by programs like Wine to run 16-bit
1080 protected mode legacy code on x86 processors. Disabling
1081 this option saves about 300 bytes on i386, or around 6K text
1082 plus 16K runtime memory on x86-64,
1086 depends on X86_16BIT && X86_32
1090 depends on X86_16BIT && X86_64
1092 config X86_VSYSCALL_EMULATION
1093 bool "Enable vsyscall emulation" if EXPERT
1097 This enables emulation of the legacy vsyscall page. Disabling
1098 it is roughly equivalent to booting with vsyscall=none, except
1099 that it will also disable the helpful warning if a program
1100 tries to use a vsyscall. With this option set to N, offending
1101 programs will just segfault, citing addresses of the form
1104 This option is required by many programs built before 2013, and
1105 care should be used even with newer programs if set to N.
1107 Disabling this option saves about 7K of kernel size and
1108 possibly 4K of additional runtime pagetable memory.
1111 tristate "Toshiba Laptop support"
1114 This adds a driver to safely access the System Management Mode of
1115 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1116 not work on models with a Phoenix BIOS. The System Management Mode
1117 is used to set the BIOS and power saving options on Toshiba portables.
1119 For information on utilities to make use of this driver see the
1120 Toshiba Linux utilities web site at:
1121 <http://www.buzzard.org.uk/toshiba/>.
1123 Say Y if you intend to run this kernel on a Toshiba portable.
1127 tristate "Dell i8k legacy laptop support"
1129 select SENSORS_DELL_SMM
1131 This option enables legacy /proc/i8k userspace interface in hwmon
1132 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1133 temperature and allows controlling fan speeds of Dell laptops via
1134 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1135 it reports also power and hotkey status. For fan speed control is
1136 needed userspace package i8kutils.
1138 Say Y if you intend to run this kernel on old Dell laptops or want to
1139 use userspace package i8kutils.
1142 config X86_REBOOTFIXUPS
1143 bool "Enable X86 board specific fixups for reboot"
1146 This enables chipset and/or board specific fixups to be done
1147 in order to get reboot to work correctly. This is only needed on
1148 some combinations of hardware and BIOS. The symptom, for which
1149 this config is intended, is when reboot ends with a stalled/hung
1152 Currently, the only fixup is for the Geode machines using
1153 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1155 Say Y if you want to enable the fixup. Currently, it's safe to
1156 enable this option even if you don't need it.
1160 bool "CPU microcode loading support"
1162 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1163 depends on BLK_DEV_INITRD
1167 If you say Y here, you will be able to update the microcode on
1168 certain Intel and AMD processors. The Intel support is for the
1169 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1170 Xeon etc. The AMD support is for families 0x10 and later. You will
1171 obviously need the actual microcode binary data itself which is not
1172 shipped with the Linux kernel.
1174 This option selects the general module only, you need to select
1175 at least one vendor specific module as well.
1177 To compile this driver as a module, choose M here: the module
1178 will be called microcode.
1180 config MICROCODE_INTEL
1181 bool "Intel microcode loading support"
1182 depends on MICROCODE
1186 This options enables microcode patch loading support for Intel
1189 For the current Intel microcode data package go to
1190 <https://downloadcenter.intel.com> and search for
1191 'Linux Processor Microcode Data File'.
1193 config MICROCODE_AMD
1194 bool "AMD microcode loading support"
1195 depends on MICROCODE
1198 If you select this option, microcode patch loading support for AMD
1199 processors will be enabled.
1201 config MICROCODE_OLD_INTERFACE
1203 depends on MICROCODE
1206 tristate "/dev/cpu/*/msr - Model-specific register support"
1208 This device gives privileged processes access to the x86
1209 Model-Specific Registers (MSRs). It is a character device with
1210 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1211 MSR accesses are directed to a specific CPU on multi-processor
1215 tristate "/dev/cpu/*/cpuid - CPU information support"
1217 This device gives processes access to the x86 CPUID instruction to
1218 be executed on a specific processor. It is a character device
1219 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1223 prompt "High Memory Support"
1230 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1231 However, the address space of 32-bit x86 processors is only 4
1232 Gigabytes large. That means that, if you have a large amount of
1233 physical memory, not all of it can be "permanently mapped" by the
1234 kernel. The physical memory that's not permanently mapped is called
1237 If you are compiling a kernel which will never run on a machine with
1238 more than 1 Gigabyte total physical RAM, answer "off" here (default
1239 choice and suitable for most users). This will result in a "3GB/1GB"
1240 split: 3GB are mapped so that each process sees a 3GB virtual memory
1241 space and the remaining part of the 4GB virtual memory space is used
1242 by the kernel to permanently map as much physical memory as
1245 If the machine has between 1 and 4 Gigabytes physical RAM, then
1248 If more than 4 Gigabytes is used then answer "64GB" here. This
1249 selection turns Intel PAE (Physical Address Extension) mode on.
1250 PAE implements 3-level paging on IA32 processors. PAE is fully
1251 supported by Linux, PAE mode is implemented on all recent Intel
1252 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1253 then the kernel will not boot on CPUs that don't support PAE!
1255 The actual amount of total physical memory will either be
1256 auto detected or can be forced by using a kernel command line option
1257 such as "mem=256M". (Try "man bootparam" or see the documentation of
1258 your boot loader (lilo or loadlin) about how to pass options to the
1259 kernel at boot time.)
1261 If unsure, say "off".
1266 Select this if you have a 32-bit processor and between 1 and 4
1267 gigabytes of physical RAM.
1274 Select this if you have a 32-bit processor and more than 4
1275 gigabytes of physical RAM.
1280 prompt "Memory split" if EXPERT
1284 Select the desired split between kernel and user memory.
1286 If the address range available to the kernel is less than the
1287 physical memory installed, the remaining memory will be available
1288 as "high memory". Accessing high memory is a little more costly
1289 than low memory, as it needs to be mapped into the kernel first.
1290 Note that increasing the kernel address space limits the range
1291 available to user programs, making the address space there
1292 tighter. Selecting anything other than the default 3G/1G split
1293 will also likely make your kernel incompatible with binary-only
1296 If you are not absolutely sure what you are doing, leave this
1300 bool "3G/1G user/kernel split"
1301 config VMSPLIT_3G_OPT
1303 bool "3G/1G user/kernel split (for full 1G low memory)"
1305 bool "2G/2G user/kernel split"
1306 config VMSPLIT_2G_OPT
1308 bool "2G/2G user/kernel split (for full 2G low memory)"
1310 bool "1G/3G user/kernel split"
1315 default 0xB0000000 if VMSPLIT_3G_OPT
1316 default 0x80000000 if VMSPLIT_2G
1317 default 0x78000000 if VMSPLIT_2G_OPT
1318 default 0x40000000 if VMSPLIT_1G
1324 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1327 bool "PAE (Physical Address Extension) Support"
1328 depends on X86_32 && !HIGHMEM4G
1331 PAE is required for NX support, and furthermore enables
1332 larger swapspace support for non-overcommit purposes. It
1333 has the cost of more pagetable lookup overhead, and also
1334 consumes more pagetable space per process.
1336 config ARCH_PHYS_ADDR_T_64BIT
1338 depends on X86_64 || X86_PAE
1340 config ARCH_DMA_ADDR_T_64BIT
1342 depends on X86_64 || HIGHMEM64G
1344 config X86_DIRECT_GBPAGES
1346 depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1348 Certain kernel features effectively disable kernel
1349 linear 1 GB mappings (even if the CPU otherwise
1350 supports them), so don't confuse the user by printing
1351 that we have them enabled.
1353 # Common NUMA Features
1355 bool "Numa Memory Allocation and Scheduler Support"
1357 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1358 default y if X86_BIGSMP
1360 Enable NUMA (Non Uniform Memory Access) support.
1362 The kernel will try to allocate memory used by a CPU on the
1363 local memory controller of the CPU and add some more
1364 NUMA awareness to the kernel.
1366 For 64-bit this is recommended if the system is Intel Core i7
1367 (or later), AMD Opteron, or EM64T NUMA.
1369 For 32-bit this is only needed if you boot a 32-bit
1370 kernel on a 64-bit NUMA platform.
1372 Otherwise, you should say N.
1376 prompt "Old style AMD Opteron NUMA detection"
1377 depends on X86_64 && NUMA && PCI
1379 Enable AMD NUMA node topology detection. You should say Y here if
1380 you have a multi processor AMD system. This uses an old method to
1381 read the NUMA configuration directly from the builtin Northbridge
1382 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1383 which also takes priority if both are compiled in.
1385 config X86_64_ACPI_NUMA
1387 prompt "ACPI NUMA detection"
1388 depends on X86_64 && NUMA && ACPI && PCI
1391 Enable ACPI SRAT based node topology detection.
1393 # Some NUMA nodes have memory ranges that span
1394 # other nodes. Even though a pfn is valid and
1395 # between a node's start and end pfns, it may not
1396 # reside on that node. See memmap_init_zone()
1398 config NODES_SPAN_OTHER_NODES
1400 depends on X86_64_ACPI_NUMA
1403 bool "NUMA emulation"
1406 Enable NUMA emulation. A flat machine will be split
1407 into virtual nodes when booted with "numa=fake=N", where N is the
1408 number of nodes. This is only useful for debugging.
1411 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1413 default "10" if MAXSMP
1414 default "6" if X86_64
1416 depends on NEED_MULTIPLE_NODES
1418 Specify the maximum number of NUMA Nodes available on the target
1419 system. Increases memory reserved to accommodate various tables.
1421 config ARCH_HAVE_MEMORY_PRESENT
1423 depends on X86_32 && DISCONTIGMEM
1425 config NEED_NODE_MEMMAP_SIZE
1427 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1429 config ARCH_FLATMEM_ENABLE
1431 depends on X86_32 && !NUMA
1433 config ARCH_DISCONTIGMEM_ENABLE
1435 depends on NUMA && X86_32
1437 config ARCH_DISCONTIGMEM_DEFAULT
1439 depends on NUMA && X86_32
1441 config ARCH_SPARSEMEM_ENABLE
1443 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1444 select SPARSEMEM_STATIC if X86_32
1445 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1447 config ARCH_SPARSEMEM_DEFAULT
1451 config ARCH_SELECT_MEMORY_MODEL
1453 depends on ARCH_SPARSEMEM_ENABLE
1455 config ARCH_MEMORY_PROBE
1456 bool "Enable sysfs memory/probe interface"
1457 depends on X86_64 && MEMORY_HOTPLUG
1459 This option enables a sysfs memory/probe interface for testing.
1460 See Documentation/memory-hotplug.txt for more information.
1461 If you are unsure how to answer this question, answer N.
1463 config ARCH_PROC_KCORE_TEXT
1465 depends on X86_64 && PROC_KCORE
1467 config ILLEGAL_POINTER_VALUE
1470 default 0xdead000000000000 if X86_64
1474 config X86_PMEM_LEGACY_DEVICE
1477 config X86_PMEM_LEGACY
1478 tristate "Support non-standard NVDIMMs and ADR protected memory"
1479 depends on PHYS_ADDR_T_64BIT
1481 select X86_PMEM_LEGACY_DEVICE
1484 Treat memory marked using the non-standard e820 type of 12 as used
1485 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1486 The kernel will offer these regions to the 'pmem' driver so
1487 they can be used for persistent storage.
1492 bool "Allocate 3rd-level pagetables from highmem"
1495 The VM uses one page table entry for each page of physical memory.
1496 For systems with a lot of RAM, this can be wasteful of precious
1497 low memory. Setting this option will put user-space page table
1498 entries in high memory.
1500 config X86_CHECK_BIOS_CORRUPTION
1501 bool "Check for low memory corruption"
1503 Periodically check for memory corruption in low memory, which
1504 is suspected to be caused by BIOS. Even when enabled in the
1505 configuration, it is disabled at runtime. Enable it by
1506 setting "memory_corruption_check=1" on the kernel command
1507 line. By default it scans the low 64k of memory every 60
1508 seconds; see the memory_corruption_check_size and
1509 memory_corruption_check_period parameters in
1510 Documentation/kernel-parameters.txt to adjust this.
1512 When enabled with the default parameters, this option has
1513 almost no overhead, as it reserves a relatively small amount
1514 of memory and scans it infrequently. It both detects corruption
1515 and prevents it from affecting the running system.
1517 It is, however, intended as a diagnostic tool; if repeatable
1518 BIOS-originated corruption always affects the same memory,
1519 you can use memmap= to prevent the kernel from using that
1522 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1523 bool "Set the default setting of memory_corruption_check"
1524 depends on X86_CHECK_BIOS_CORRUPTION
1527 Set whether the default state of memory_corruption_check is
1530 config X86_RESERVE_LOW
1531 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1535 Specify the amount of low memory to reserve for the BIOS.
1537 The first page contains BIOS data structures that the kernel
1538 must not use, so that page must always be reserved.
1540 By default we reserve the first 64K of physical RAM, as a
1541 number of BIOSes are known to corrupt that memory range
1542 during events such as suspend/resume or monitor cable
1543 insertion, so it must not be used by the kernel.
1545 You can set this to 4 if you are absolutely sure that you
1546 trust the BIOS to get all its memory reservations and usages
1547 right. If you know your BIOS have problems beyond the
1548 default 64K area, you can set this to 640 to avoid using the
1549 entire low memory range.
1551 If you have doubts about the BIOS (e.g. suspend/resume does
1552 not work or there's kernel crashes after certain hardware
1553 hotplug events) then you might want to enable
1554 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1555 typical corruption patterns.
1557 Leave this to the default value of 64 if you are unsure.
1559 config MATH_EMULATION
1561 depends on MODIFY_LDT_SYSCALL
1562 prompt "Math emulation" if X86_32
1564 Linux can emulate a math coprocessor (used for floating point
1565 operations) if you don't have one. 486DX and Pentium processors have
1566 a math coprocessor built in, 486SX and 386 do not, unless you added
1567 a 487DX or 387, respectively. (The messages during boot time can
1568 give you some hints here ["man dmesg"].) Everyone needs either a
1569 coprocessor or this emulation.
1571 If you don't have a math coprocessor, you need to say Y here; if you
1572 say Y here even though you have a coprocessor, the coprocessor will
1573 be used nevertheless. (This behavior can be changed with the kernel
1574 command line option "no387", which comes handy if your coprocessor
1575 is broken. Try "man bootparam" or see the documentation of your boot
1576 loader (lilo or loadlin) about how to pass options to the kernel at
1577 boot time.) This means that it is a good idea to say Y here if you
1578 intend to use this kernel on different machines.
1580 More information about the internals of the Linux math coprocessor
1581 emulation can be found in <file:arch/x86/math-emu/README>.
1583 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1584 kernel, it won't hurt.
1588 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1590 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1591 the Memory Type Range Registers (MTRRs) may be used to control
1592 processor access to memory ranges. This is most useful if you have
1593 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1594 allows bus write transfers to be combined into a larger transfer
1595 before bursting over the PCI/AGP bus. This can increase performance
1596 of image write operations 2.5 times or more. Saying Y here creates a
1597 /proc/mtrr file which may be used to manipulate your processor's
1598 MTRRs. Typically the X server should use this.
1600 This code has a reasonably generic interface so that similar
1601 control registers on other processors can be easily supported
1604 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1605 Registers (ARRs) which provide a similar functionality to MTRRs. For
1606 these, the ARRs are used to emulate the MTRRs.
1607 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1608 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1609 write-combining. All of these processors are supported by this code
1610 and it makes sense to say Y here if you have one of them.
1612 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1613 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1614 can lead to all sorts of problems, so it's good to say Y here.
1616 You can safely say Y even if your machine doesn't have MTRRs, you'll
1617 just add about 9 KB to your kernel.
1619 See <file:Documentation/x86/mtrr.txt> for more information.
1621 config MTRR_SANITIZER
1623 prompt "MTRR cleanup support"
1626 Convert MTRR layout from continuous to discrete, so X drivers can
1627 add writeback entries.
1629 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1630 The largest mtrr entry size for a continuous block can be set with
1635 config MTRR_SANITIZER_ENABLE_DEFAULT
1636 int "MTRR cleanup enable value (0-1)"
1639 depends on MTRR_SANITIZER
1641 Enable mtrr cleanup default value
1643 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1644 int "MTRR cleanup spare reg num (0-7)"
1647 depends on MTRR_SANITIZER
1649 mtrr cleanup spare entries default, it can be changed via
1650 mtrr_spare_reg_nr=N on the kernel command line.
1654 prompt "x86 PAT support" if EXPERT
1657 Use PAT attributes to setup page level cache control.
1659 PATs are the modern equivalents of MTRRs and are much more
1660 flexible than MTRRs.
1662 Say N here if you see bootup problems (boot crash, boot hang,
1663 spontaneous reboots) or a non-working video driver.
1667 config ARCH_USES_PG_UNCACHED
1673 prompt "x86 architectural random number generator" if EXPERT
1675 Enable the x86 architectural RDRAND instruction
1676 (Intel Bull Mountain technology) to generate random numbers.
1677 If supported, this is a high bandwidth, cryptographically
1678 secure hardware random number generator.
1682 prompt "Supervisor Mode Access Prevention" if EXPERT
1684 Supervisor Mode Access Prevention (SMAP) is a security
1685 feature in newer Intel processors. There is a small
1686 performance cost if this enabled and turned on; there is
1687 also a small increase in the kernel size if this is enabled.
1691 config X86_INTEL_MPX
1692 prompt "Intel MPX (Memory Protection Extensions)"
1694 depends on CPU_SUP_INTEL
1696 MPX provides hardware features that can be used in
1697 conjunction with compiler-instrumented code to check
1698 memory references. It is designed to detect buffer
1699 overflow or underflow bugs.
1701 This option enables running applications which are
1702 instrumented or otherwise use MPX. It does not use MPX
1703 itself inside the kernel or to protect the kernel
1704 against bad memory references.
1706 Enabling this option will make the kernel larger:
1707 ~8k of kernel text and 36 bytes of data on a 64-bit
1708 defconfig. It adds a long to the 'mm_struct' which
1709 will increase the kernel memory overhead of each
1710 process and adds some branches to paths used during
1711 exec() and munmap().
1713 For details, see Documentation/x86/intel_mpx.txt
1718 bool "EFI runtime service support"
1721 select EFI_RUNTIME_WRAPPERS
1723 This enables the kernel to use EFI runtime services that are
1724 available (such as the EFI variable services).
1726 This option is only useful on systems that have EFI firmware.
1727 In addition, you should use the latest ELILO loader available
1728 at <http://elilo.sourceforge.net> in order to take advantage
1729 of EFI runtime services. However, even with this option, the
1730 resultant kernel should continue to boot on existing non-EFI
1734 bool "EFI stub support"
1735 depends on EFI && !X86_USE_3DNOW
1738 This kernel feature allows a bzImage to be loaded directly
1739 by EFI firmware without the use of a bootloader.
1741 See Documentation/efi-stub.txt for more information.
1744 bool "EFI mixed-mode support"
1745 depends on EFI_STUB && X86_64
1747 Enabling this feature allows a 64-bit kernel to be booted
1748 on a 32-bit firmware, provided that your CPU supports 64-bit
1751 Note that it is not possible to boot a mixed-mode enabled
1752 kernel via the EFI boot stub - a bootloader that supports
1753 the EFI handover protocol must be used.
1759 prompt "Enable seccomp to safely compute untrusted bytecode"
1761 This kernel feature is useful for number crunching applications
1762 that may need to compute untrusted bytecode during their
1763 execution. By using pipes or other transports made available to
1764 the process as file descriptors supporting the read/write
1765 syscalls, it's possible to isolate those applications in
1766 their own address space using seccomp. Once seccomp is
1767 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1768 and the task is only allowed to execute a few safe syscalls
1769 defined by each seccomp mode.
1771 If unsure, say Y. Only embedded should say N here.
1773 source kernel/Kconfig.hz
1776 bool "kexec system call"
1779 kexec is a system call that implements the ability to shutdown your
1780 current kernel, and to start another kernel. It is like a reboot
1781 but it is independent of the system firmware. And like a reboot
1782 you can start any kernel with it, not just Linux.
1784 The name comes from the similarity to the exec system call.
1786 It is an ongoing process to be certain the hardware in a machine
1787 is properly shutdown, so do not be surprised if this code does not
1788 initially work for you. As of this writing the exact hardware
1789 interface is strongly in flux, so no good recommendation can be
1793 bool "kexec file based system call"
1798 depends on CRYPTO_SHA256=y
1800 This is new version of kexec system call. This system call is
1801 file based and takes file descriptors as system call argument
1802 for kernel and initramfs as opposed to list of segments as
1803 accepted by previous system call.
1805 config KEXEC_VERIFY_SIG
1806 bool "Verify kernel signature during kexec_file_load() syscall"
1807 depends on KEXEC_FILE
1809 This option makes kernel signature verification mandatory for
1810 the kexec_file_load() syscall.
1812 In addition to that option, you need to enable signature
1813 verification for the corresponding kernel image type being
1814 loaded in order for this to work.
1816 config KEXEC_BZIMAGE_VERIFY_SIG
1817 bool "Enable bzImage signature verification support"
1818 depends on KEXEC_VERIFY_SIG
1819 depends on SIGNED_PE_FILE_VERIFICATION
1820 select SYSTEM_TRUSTED_KEYRING
1822 Enable bzImage signature verification support.
1825 bool "kernel crash dumps"
1826 depends on X86_64 || (X86_32 && HIGHMEM)
1828 Generate crash dump after being started by kexec.
1829 This should be normally only set in special crash dump kernels
1830 which are loaded in the main kernel with kexec-tools into
1831 a specially reserved region and then later executed after
1832 a crash by kdump/kexec. The crash dump kernel must be compiled
1833 to a memory address not used by the main kernel or BIOS using
1834 PHYSICAL_START, or it must be built as a relocatable image
1835 (CONFIG_RELOCATABLE=y).
1836 For more details see Documentation/kdump/kdump.txt
1840 depends on KEXEC && HIBERNATION
1842 Jump between original kernel and kexeced kernel and invoke
1843 code in physical address mode via KEXEC
1845 config PHYSICAL_START
1846 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1849 This gives the physical address where the kernel is loaded.
1851 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1852 bzImage will decompress itself to above physical address and
1853 run from there. Otherwise, bzImage will run from the address where
1854 it has been loaded by the boot loader and will ignore above physical
1857 In normal kdump cases one does not have to set/change this option
1858 as now bzImage can be compiled as a completely relocatable image
1859 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1860 address. This option is mainly useful for the folks who don't want
1861 to use a bzImage for capturing the crash dump and want to use a
1862 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1863 to be specifically compiled to run from a specific memory area
1864 (normally a reserved region) and this option comes handy.
1866 So if you are using bzImage for capturing the crash dump,
1867 leave the value here unchanged to 0x1000000 and set
1868 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1869 for capturing the crash dump change this value to start of
1870 the reserved region. In other words, it can be set based on
1871 the "X" value as specified in the "crashkernel=YM@XM"
1872 command line boot parameter passed to the panic-ed
1873 kernel. Please take a look at Documentation/kdump/kdump.txt
1874 for more details about crash dumps.
1876 Usage of bzImage for capturing the crash dump is recommended as
1877 one does not have to build two kernels. Same kernel can be used
1878 as production kernel and capture kernel. Above option should have
1879 gone away after relocatable bzImage support is introduced. But it
1880 is present because there are users out there who continue to use
1881 vmlinux for dump capture. This option should go away down the
1884 Don't change this unless you know what you are doing.
1887 bool "Build a relocatable kernel"
1890 This builds a kernel image that retains relocation information
1891 so it can be loaded someplace besides the default 1MB.
1892 The relocations tend to make the kernel binary about 10% larger,
1893 but are discarded at runtime.
1895 One use is for the kexec on panic case where the recovery kernel
1896 must live at a different physical address than the primary
1899 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1900 it has been loaded at and the compile time physical address
1901 (CONFIG_PHYSICAL_START) is used as the minimum location.
1903 config RANDOMIZE_BASE
1904 bool "Randomize the address of the kernel image"
1905 depends on RELOCATABLE
1908 Randomizes the physical and virtual address at which the
1909 kernel image is decompressed, as a security feature that
1910 deters exploit attempts relying on knowledge of the location
1911 of kernel internals.
1913 Entropy is generated using the RDRAND instruction if it is
1914 supported. If RDTSC is supported, it is used as well. If
1915 neither RDRAND nor RDTSC are supported, then randomness is
1916 read from the i8254 timer.
1918 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1919 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1920 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1921 minimum of 2MiB, only 10 bits of entropy is theoretically
1922 possible. At best, due to page table layouts, 64-bit can use
1923 9 bits of entropy and 32-bit uses 8 bits.
1927 config RANDOMIZE_BASE_MAX_OFFSET
1928 hex "Maximum kASLR offset allowed" if EXPERT
1929 depends on RANDOMIZE_BASE
1930 range 0x0 0x20000000 if X86_32
1931 default "0x20000000" if X86_32
1932 range 0x0 0x40000000 if X86_64
1933 default "0x40000000" if X86_64
1935 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1936 memory is used to determine the maximal offset in bytes that will
1937 be applied to the kernel when kernel Address Space Layout
1938 Randomization (kASLR) is active. This must be a multiple of
1941 On 32-bit this is limited to 512MiB by page table layouts. The
1944 On 64-bit this is limited by how the kernel fixmap page table is
1945 positioned, so this cannot be larger than 1GiB currently. Without
1946 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1947 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1948 modules area will shrink to compensate, up to the current maximum
1949 1GiB to 1GiB split. The default is 1GiB.
1951 If unsure, leave at the default value.
1953 # Relocation on x86 needs some additional build support
1954 config X86_NEED_RELOCS
1956 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1958 config PHYSICAL_ALIGN
1959 hex "Alignment value to which kernel should be aligned"
1961 range 0x2000 0x1000000 if X86_32
1962 range 0x200000 0x1000000 if X86_64
1964 This value puts the alignment restrictions on physical address
1965 where kernel is loaded and run from. Kernel is compiled for an
1966 address which meets above alignment restriction.
1968 If bootloader loads the kernel at a non-aligned address and
1969 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1970 address aligned to above value and run from there.
1972 If bootloader loads the kernel at a non-aligned address and
1973 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1974 load address and decompress itself to the address it has been
1975 compiled for and run from there. The address for which kernel is
1976 compiled already meets above alignment restrictions. Hence the
1977 end result is that kernel runs from a physical address meeting
1978 above alignment restrictions.
1980 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1981 this value must be a multiple of 0x200000.
1983 Don't change this unless you know what you are doing.
1986 bool "Support for hot-pluggable CPUs"
1989 Say Y here to allow turning CPUs off and on. CPUs can be
1990 controlled through /sys/devices/system/cpu.
1991 ( Note: power management support will enable this option
1992 automatically on SMP systems. )
1993 Say N if you want to disable CPU hotplug.
1995 config BOOTPARAM_HOTPLUG_CPU0
1996 bool "Set default setting of cpu0_hotpluggable"
1998 depends on HOTPLUG_CPU
2000 Set whether default state of cpu0_hotpluggable is on or off.
2002 Say Y here to enable CPU0 hotplug by default. If this switch
2003 is turned on, there is no need to give cpu0_hotplug kernel
2004 parameter and the CPU0 hotplug feature is enabled by default.
2006 Please note: there are two known CPU0 dependencies if you want
2007 to enable the CPU0 hotplug feature either by this switch or by
2008 cpu0_hotplug kernel parameter.
2010 First, resume from hibernate or suspend always starts from CPU0.
2011 So hibernate and suspend are prevented if CPU0 is offline.
2013 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2014 offline if any interrupt can not migrate out of CPU0. There may
2015 be other CPU0 dependencies.
2017 Please make sure the dependencies are under your control before
2018 you enable this feature.
2020 Say N if you don't want to enable CPU0 hotplug feature by default.
2021 You still can enable the CPU0 hotplug feature at boot by kernel
2022 parameter cpu0_hotplug.
2024 config DEBUG_HOTPLUG_CPU0
2026 prompt "Debug CPU0 hotplug"
2027 depends on HOTPLUG_CPU
2029 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2030 soon as possible and boots up userspace with CPU0 offlined. User
2031 can online CPU0 back after boot time.
2033 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2034 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2035 compilation or giving cpu0_hotplug kernel parameter at boot.
2041 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2042 depends on X86_32 || IA32_EMULATION
2044 Certain buggy versions of glibc will crash if they are
2045 presented with a 32-bit vDSO that is not mapped at the address
2046 indicated in its segment table.
2048 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2049 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2050 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2051 the only released version with the bug, but OpenSUSE 9
2052 contains a buggy "glibc 2.3.2".
2054 The symptom of the bug is that everything crashes on startup, saying:
2055 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2057 Saying Y here changes the default value of the vdso32 boot
2058 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2059 This works around the glibc bug but hurts performance.
2061 If unsure, say N: if you are compiling your own kernel, you
2062 are unlikely to be using a buggy version of glibc.
2065 prompt "vsyscall table for legacy applications"
2067 default LEGACY_VSYSCALL_EMULATE
2069 Legacy user code that does not know how to find the vDSO expects
2070 to be able to issue three syscalls by calling fixed addresses in
2071 kernel space. Since this location is not randomized with ASLR,
2072 it can be used to assist security vulnerability exploitation.
2074 This setting can be changed at boot time via the kernel command
2075 line parameter vsyscall=[native|emulate|none].
2077 On a system with recent enough glibc (2.14 or newer) and no
2078 static binaries, you can say None without a performance penalty
2079 to improve security.
2081 If unsure, select "Emulate".
2083 config LEGACY_VSYSCALL_NATIVE
2086 Actual executable code is located in the fixed vsyscall
2087 address mapping, implementing time() efficiently. Since
2088 this makes the mapping executable, it can be used during
2089 security vulnerability exploitation (traditionally as
2090 ROP gadgets). This configuration is not recommended.
2092 config LEGACY_VSYSCALL_EMULATE
2095 The kernel traps and emulates calls into the fixed
2096 vsyscall address mapping. This makes the mapping
2097 non-executable, but it still contains known contents,
2098 which could be used in certain rare security vulnerability
2099 exploits. This configuration is recommended when userspace
2100 still uses the vsyscall area.
2102 config LEGACY_VSYSCALL_NONE
2105 There will be no vsyscall mapping at all. This will
2106 eliminate any risk of ASLR bypass due to the vsyscall
2107 fixed address mapping. Attempts to use the vsyscalls
2108 will be reported to dmesg, so that either old or
2109 malicious userspace programs can be identified.
2114 bool "Built-in kernel command line"
2116 Allow for specifying boot arguments to the kernel at
2117 build time. On some systems (e.g. embedded ones), it is
2118 necessary or convenient to provide some or all of the
2119 kernel boot arguments with the kernel itself (that is,
2120 to not rely on the boot loader to provide them.)
2122 To compile command line arguments into the kernel,
2123 set this option to 'Y', then fill in the
2124 boot arguments in CONFIG_CMDLINE.
2126 Systems with fully functional boot loaders (i.e. non-embedded)
2127 should leave this option set to 'N'.
2130 string "Built-in kernel command string"
2131 depends on CMDLINE_BOOL
2134 Enter arguments here that should be compiled into the kernel
2135 image and used at boot time. If the boot loader provides a
2136 command line at boot time, it is appended to this string to
2137 form the full kernel command line, when the system boots.
2139 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2140 change this behavior.
2142 In most cases, the command line (whether built-in or provided
2143 by the boot loader) should specify the device for the root
2146 config CMDLINE_OVERRIDE
2147 bool "Built-in command line overrides boot loader arguments"
2148 depends on CMDLINE_BOOL
2150 Set this option to 'Y' to have the kernel ignore the boot loader
2151 command line, and use ONLY the built-in command line.
2153 This is used to work around broken boot loaders. This should
2154 be set to 'N' under normal conditions.
2156 config MODIFY_LDT_SYSCALL
2157 bool "Enable the LDT (local descriptor table)" if EXPERT
2160 Linux can allow user programs to install a per-process x86
2161 Local Descriptor Table (LDT) using the modify_ldt(2) system
2162 call. This is required to run 16-bit or segmented code such as
2163 DOSEMU or some Wine programs. It is also used by some very old
2164 threading libraries.
2166 Enabling this feature adds a small amount of overhead to
2167 context switches and increases the low-level kernel attack
2168 surface. Disabling it removes the modify_ldt(2) system call.
2170 Saying 'N' here may make sense for embedded or server kernels.
2172 source "kernel/livepatch/Kconfig"
2176 config ARCH_ENABLE_MEMORY_HOTPLUG
2178 depends on X86_64 || (X86_32 && HIGHMEM)
2180 config ARCH_ENABLE_MEMORY_HOTREMOVE
2182 depends on MEMORY_HOTPLUG
2184 config USE_PERCPU_NUMA_NODE_ID
2188 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2190 depends on X86_64 || X86_PAE
2192 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2194 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2196 menu "Power management and ACPI options"
2198 config ARCH_HIBERNATION_HEADER
2200 depends on X86_64 && HIBERNATION
2202 source "kernel/power/Kconfig"
2204 source "drivers/acpi/Kconfig"
2206 source "drivers/sfi/Kconfig"
2213 tristate "APM (Advanced Power Management) BIOS support"
2214 depends on X86_32 && PM_SLEEP
2216 APM is a BIOS specification for saving power using several different
2217 techniques. This is mostly useful for battery powered laptops with
2218 APM compliant BIOSes. If you say Y here, the system time will be
2219 reset after a RESUME operation, the /proc/apm device will provide
2220 battery status information, and user-space programs will receive
2221 notification of APM "events" (e.g. battery status change).
2223 If you select "Y" here, you can disable actual use of the APM
2224 BIOS by passing the "apm=off" option to the kernel at boot time.
2226 Note that the APM support is almost completely disabled for
2227 machines with more than one CPU.
2229 In order to use APM, you will need supporting software. For location
2230 and more information, read <file:Documentation/power/apm-acpi.txt>
2231 and the Battery Powered Linux mini-HOWTO, available from
2232 <http://www.tldp.org/docs.html#howto>.
2234 This driver does not spin down disk drives (see the hdparm(8)
2235 manpage ("man 8 hdparm") for that), and it doesn't turn off
2236 VESA-compliant "green" monitors.
2238 This driver does not support the TI 4000M TravelMate and the ACER
2239 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2240 desktop machines also don't have compliant BIOSes, and this driver
2241 may cause those machines to panic during the boot phase.
2243 Generally, if you don't have a battery in your machine, there isn't
2244 much point in using this driver and you should say N. If you get
2245 random kernel OOPSes or reboots that don't seem to be related to
2246 anything, try disabling/enabling this option (or disabling/enabling
2249 Some other things you should try when experiencing seemingly random,
2252 1) make sure that you have enough swap space and that it is
2254 2) pass the "no-hlt" option to the kernel
2255 3) switch on floating point emulation in the kernel and pass
2256 the "no387" option to the kernel
2257 4) pass the "floppy=nodma" option to the kernel
2258 5) pass the "mem=4M" option to the kernel (thereby disabling
2259 all but the first 4 MB of RAM)
2260 6) make sure that the CPU is not over clocked.
2261 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2262 8) disable the cache from your BIOS settings
2263 9) install a fan for the video card or exchange video RAM
2264 10) install a better fan for the CPU
2265 11) exchange RAM chips
2266 12) exchange the motherboard.
2268 To compile this driver as a module, choose M here: the
2269 module will be called apm.
2273 config APM_IGNORE_USER_SUSPEND
2274 bool "Ignore USER SUSPEND"
2276 This option will ignore USER SUSPEND requests. On machines with a
2277 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2278 series notebooks, it is necessary to say Y because of a BIOS bug.
2280 config APM_DO_ENABLE
2281 bool "Enable PM at boot time"
2283 Enable APM features at boot time. From page 36 of the APM BIOS
2284 specification: "When disabled, the APM BIOS does not automatically
2285 power manage devices, enter the Standby State, enter the Suspend
2286 State, or take power saving steps in response to CPU Idle calls."
2287 This driver will make CPU Idle calls when Linux is idle (unless this
2288 feature is turned off -- see "Do CPU IDLE calls", below). This
2289 should always save battery power, but more complicated APM features
2290 will be dependent on your BIOS implementation. You may need to turn
2291 this option off if your computer hangs at boot time when using APM
2292 support, or if it beeps continuously instead of suspending. Turn
2293 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2294 T400CDT. This is off by default since most machines do fine without
2299 bool "Make CPU Idle calls when idle"
2301 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2302 On some machines, this can activate improved power savings, such as
2303 a slowed CPU clock rate, when the machine is idle. These idle calls
2304 are made after the idle loop has run for some length of time (e.g.,
2305 333 mS). On some machines, this will cause a hang at boot time or
2306 whenever the CPU becomes idle. (On machines with more than one CPU,
2307 this option does nothing.)
2309 config APM_DISPLAY_BLANK
2310 bool "Enable console blanking using APM"
2312 Enable console blanking using the APM. Some laptops can use this to
2313 turn off the LCD backlight when the screen blanker of the Linux
2314 virtual console blanks the screen. Note that this is only used by
2315 the virtual console screen blanker, and won't turn off the backlight
2316 when using the X Window system. This also doesn't have anything to
2317 do with your VESA-compliant power-saving monitor. Further, this
2318 option doesn't work for all laptops -- it might not turn off your
2319 backlight at all, or it might print a lot of errors to the console,
2320 especially if you are using gpm.
2322 config APM_ALLOW_INTS
2323 bool "Allow interrupts during APM BIOS calls"
2325 Normally we disable external interrupts while we are making calls to
2326 the APM BIOS as a measure to lessen the effects of a badly behaving
2327 BIOS implementation. The BIOS should reenable interrupts if it
2328 needs to. Unfortunately, some BIOSes do not -- especially those in
2329 many of the newer IBM Thinkpads. If you experience hangs when you
2330 suspend, try setting this to Y. Otherwise, say N.
2334 source "drivers/cpufreq/Kconfig"
2336 source "drivers/cpuidle/Kconfig"
2338 source "drivers/idle/Kconfig"
2343 menu "Bus options (PCI etc.)"
2349 Find out whether you have a PCI motherboard. PCI is the name of a
2350 bus system, i.e. the way the CPU talks to the other stuff inside
2351 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2352 VESA. If you have PCI, say Y, otherwise N.
2355 prompt "PCI access mode"
2356 depends on X86_32 && PCI
2359 On PCI systems, the BIOS can be used to detect the PCI devices and
2360 determine their configuration. However, some old PCI motherboards
2361 have BIOS bugs and may crash if this is done. Also, some embedded
2362 PCI-based systems don't have any BIOS at all. Linux can also try to
2363 detect the PCI hardware directly without using the BIOS.
2365 With this option, you can specify how Linux should detect the
2366 PCI devices. If you choose "BIOS", the BIOS will be used,
2367 if you choose "Direct", the BIOS won't be used, and if you
2368 choose "MMConfig", then PCI Express MMCONFIG will be used.
2369 If you choose "Any", the kernel will try MMCONFIG, then the
2370 direct access method and falls back to the BIOS if that doesn't
2371 work. If unsure, go with the default, which is "Any".
2376 config PCI_GOMMCONFIG
2393 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2395 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2398 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2402 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2406 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2410 depends on PCI && XEN
2418 bool "Support mmconfig PCI config space access"
2419 depends on X86_64 && PCI && ACPI
2421 config PCI_CNB20LE_QUIRK
2422 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2425 Read the PCI windows out of the CNB20LE host bridge. This allows
2426 PCI hotplug to work on systems with the CNB20LE chipset which do
2429 There's no public spec for this chipset, and this functionality
2430 is known to be incomplete.
2432 You should say N unless you know you need this.
2434 source "drivers/pci/pcie/Kconfig"
2436 source "drivers/pci/Kconfig"
2438 # x86_64 have no ISA slots, but can have ISA-style DMA.
2440 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2443 Enables ISA-style DMA support for devices requiring such controllers.
2451 Find out whether you have ISA slots on your motherboard. ISA is the
2452 name of a bus system, i.e. the way the CPU talks to the other stuff
2453 inside your box. Other bus systems are PCI, EISA, MicroChannel
2454 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2455 newer boards don't support it. If you have ISA, say Y, otherwise N.
2461 The Extended Industry Standard Architecture (EISA) bus was
2462 developed as an open alternative to the IBM MicroChannel bus.
2464 The EISA bus provided some of the features of the IBM MicroChannel
2465 bus while maintaining backward compatibility with cards made for
2466 the older ISA bus. The EISA bus saw limited use between 1988 and
2467 1995 when it was made obsolete by the PCI bus.
2469 Say Y here if you are building a kernel for an EISA-based machine.
2473 source "drivers/eisa/Kconfig"
2476 tristate "NatSemi SCx200 support"
2478 This provides basic support for National Semiconductor's
2479 (now AMD's) Geode processors. The driver probes for the
2480 PCI-IDs of several on-chip devices, so its a good dependency
2481 for other scx200_* drivers.
2483 If compiled as a module, the driver is named scx200.
2485 config SCx200HR_TIMER
2486 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2490 This driver provides a clocksource built upon the on-chip
2491 27MHz high-resolution timer. Its also a workaround for
2492 NSC Geode SC-1100's buggy TSC, which loses time when the
2493 processor goes idle (as is done by the scheduler). The
2494 other workaround is idle=poll boot option.
2497 bool "One Laptop Per Child support"
2504 Add support for detecting the unique features of the OLPC
2508 bool "OLPC XO-1 Power Management"
2509 depends on OLPC && MFD_CS5535 && PM_SLEEP
2512 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2515 bool "OLPC XO-1 Real Time Clock"
2516 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2518 Add support for the XO-1 real time clock, which can be used as a
2519 programmable wakeup source.
2522 bool "OLPC XO-1 SCI extras"
2523 depends on OLPC && OLPC_XO1_PM
2529 Add support for SCI-based features of the OLPC XO-1 laptop:
2530 - EC-driven system wakeups
2534 - AC adapter status updates
2535 - Battery status updates
2537 config OLPC_XO15_SCI
2538 bool "OLPC XO-1.5 SCI extras"
2539 depends on OLPC && ACPI
2542 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2543 - EC-driven system wakeups
2544 - AC adapter status updates
2545 - Battery status updates
2548 bool "PCEngines ALIX System Support (LED setup)"
2551 This option enables system support for the PCEngines ALIX.
2552 At present this just sets up LEDs for GPIO control on
2553 ALIX2/3/6 boards. However, other system specific setup should
2556 Note: You must still enable the drivers for GPIO and LED support
2557 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2559 Note: You have to set alix.force=1 for boards with Award BIOS.
2562 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2565 This option enables system support for the Soekris Engineering net5501.
2568 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2572 This option enables system support for the Traverse Technologies GEOS.
2575 bool "Technologic Systems TS-5500 platform support"
2577 select CHECK_SIGNATURE
2581 This option enables system support for the Technologic Systems TS-5500.
2587 depends on CPU_SUP_AMD && PCI
2589 source "drivers/pcmcia/Kconfig"
2591 source "drivers/pci/hotplug/Kconfig"
2594 tristate "RapidIO support"
2598 If enabled this option will include drivers and the core
2599 infrastructure code to support RapidIO interconnect devices.
2601 source "drivers/rapidio/Kconfig"
2604 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2606 Firmwares often provide initial graphics framebuffers so the BIOS,
2607 bootloader or kernel can show basic video-output during boot for
2608 user-guidance and debugging. Historically, x86 used the VESA BIOS
2609 Extensions and EFI-framebuffers for this, which are mostly limited
2611 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2612 framebuffers so the new generic system-framebuffer drivers can be
2613 used on x86. If the framebuffer is not compatible with the generic
2614 modes, it is adverticed as fallback platform framebuffer so legacy
2615 drivers like efifb, vesafb and uvesafb can pick it up.
2616 If this option is not selected, all system framebuffers are always
2617 marked as fallback platform framebuffers as usual.
2619 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2620 not be able to pick up generic system framebuffers if this option
2621 is selected. You are highly encouraged to enable simplefb as
2622 replacement if you select this option. simplefb can correctly deal
2623 with generic system framebuffers. But you should still keep vesafb
2624 and others enabled as fallback if a system framebuffer is
2625 incompatible with simplefb.
2632 menu "Executable file formats / Emulations"
2634 source "fs/Kconfig.binfmt"
2636 config IA32_EMULATION
2637 bool "IA32 Emulation"
2640 select COMPAT_BINFMT_ELF
2641 select ARCH_WANT_OLD_COMPAT_IPC
2643 Include code to run legacy 32-bit programs under a
2644 64-bit kernel. You should likely turn this on, unless you're
2645 100% sure that you don't have any 32-bit programs left.
2648 tristate "IA32 a.out support"
2649 depends on IA32_EMULATION
2651 Support old a.out binaries in the 32bit emulation.
2654 bool "x32 ABI for 64-bit mode"
2657 Include code to run binaries for the x32 native 32-bit ABI
2658 for 64-bit processors. An x32 process gets access to the
2659 full 64-bit register file and wide data path while leaving
2660 pointers at 32 bits for smaller memory footprint.
2662 You will need a recent binutils (2.22 or later) with
2663 elf32_x86_64 support enabled to compile a kernel with this
2668 depends on IA32_EMULATION || X86_X32
2671 config COMPAT_FOR_U64_ALIGNMENT
2674 config SYSVIPC_COMPAT
2686 config HAVE_ATOMIC_IOMAP
2690 config X86_DEV_DMA_OPS
2692 depends on X86_64 || STA2X11
2694 config X86_DMA_REMAP
2704 tristate "Volume Management Device Driver"
2707 Adds support for the Intel Volume Management Device (VMD). VMD is a
2708 secondary PCI host bridge that allows PCI Express root ports,
2709 and devices attached to them, to be removed from the default
2710 PCI domain and placed within the VMD domain. This provides
2711 more bus resources than are otherwise possible with a
2712 single domain. If you know your system provides one of these and
2713 has devices attached to it, say Y; if you are not sure, say N.
2715 source "net/Kconfig"
2717 source "drivers/Kconfig"
2719 source "drivers/firmware/Kconfig"
2723 source "arch/x86/Kconfig.debug"
2725 source "security/Kconfig"
2727 source "crypto/Kconfig"
2729 source "arch/x86/kvm/Kconfig"
2731 source "lib/Kconfig"
projects / cascardo / linux.git / blob