3 bool "64-bit kernel" if ARCH = "x86"
6 Say yes to build a 64-bit kernel - formerly known as x86_64
7 Say no to build a 32-bit kernel - formerly known as i386
20 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
21 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
23 select ARCH_CLOCKSOURCE_DATA
24 select ARCH_DISCARD_MEMBLOCK
25 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
26 select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
27 select ARCH_HAS_DEVMEM_IS_ALLOWED
28 select ARCH_HAS_ELF_RANDOMIZE
29 select ARCH_HAS_FAST_MULTIPLIER
30 select ARCH_HAS_GCOV_PROFILE_ALL
31 select ARCH_HAS_KCOV if X86_64
32 select ARCH_HAS_PMEM_API if X86_64
33 select ARCH_HAS_MMIO_FLUSH
34 select ARCH_HAS_SG_CHAIN
35 select ARCH_HAS_UBSAN_SANITIZE_ALL
36 select ARCH_HAVE_NMI_SAFE_CMPXCHG
37 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
38 select ARCH_MIGHT_HAVE_PC_PARPORT
39 select ARCH_MIGHT_HAVE_PC_SERIO
40 select ARCH_SUPPORTS_ATOMIC_RMW
41 select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
42 select ARCH_SUPPORTS_INT128 if X86_64
43 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
44 select ARCH_USE_BUILTIN_BSWAP
45 select ARCH_USE_CMPXCHG_LOCKREF if X86_64
46 select ARCH_USE_QUEUED_RWLOCKS
47 select ARCH_USE_QUEUED_SPINLOCKS
48 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if SMP
49 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
50 select ARCH_WANT_FRAME_POINTERS
51 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
52 select ARCH_WANT_OPTIONAL_GPIOLIB
53 select BUILDTIME_EXTABLE_SORT
55 select CLKSRC_I8253 if X86_32
56 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
57 select CLOCKSOURCE_WATCHDOG
58 select CLONE_BACKWARDS if X86_32
59 select COMPAT_OLD_SIGACTION if IA32_EMULATION
60 select DCACHE_WORD_ACCESS
61 select EDAC_ATOMIC_SCRUB
63 select GENERIC_CLOCKEVENTS
64 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
65 select GENERIC_CLOCKEVENTS_MIN_ADJUST
66 select GENERIC_CMOS_UPDATE
67 select GENERIC_CPU_AUTOPROBE
68 select GENERIC_EARLY_IOREMAP
69 select GENERIC_FIND_FIRST_BIT
71 select GENERIC_IRQ_PROBE
72 select GENERIC_IRQ_SHOW
73 select GENERIC_PENDING_IRQ if SMP
74 select GENERIC_SMP_IDLE_THREAD
75 select GENERIC_STRNCPY_FROM_USER
76 select GENERIC_STRNLEN_USER
77 select GENERIC_TIME_VSYSCALL
78 select HAVE_ACPI_APEI if ACPI
79 select HAVE_ACPI_APEI_NMI if ACPI
80 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
81 select HAVE_AOUT if X86_32
82 select HAVE_ARCH_AUDITSYSCALL
83 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
84 select HAVE_ARCH_JUMP_LABEL
85 select HAVE_ARCH_KASAN if X86_64 && SPARSEMEM_VMEMMAP
87 select HAVE_ARCH_KMEMCHECK
88 select HAVE_ARCH_MMAP_RND_BITS if MMU
89 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
90 select HAVE_ARCH_SECCOMP_FILTER
91 select HAVE_ARCH_SOFT_DIRTY if X86_64
92 select HAVE_ARCH_TRACEHOOK
93 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
94 select HAVE_EBPF_JIT if X86_64
95 select HAVE_CC_STACKPROTECTOR
96 select HAVE_CMPXCHG_DOUBLE
97 select HAVE_CMPXCHG_LOCAL
98 select HAVE_CONTEXT_TRACKING if X86_64
99 select HAVE_COPY_THREAD_TLS
100 select HAVE_C_RECORDMCOUNT
101 select HAVE_DEBUG_KMEMLEAK
102 select HAVE_DEBUG_STACKOVERFLOW
103 select HAVE_DMA_API_DEBUG
104 select HAVE_DMA_CONTIGUOUS
105 select HAVE_DYNAMIC_FTRACE
106 select HAVE_DYNAMIC_FTRACE_WITH_REGS
107 select HAVE_EFFICIENT_UNALIGNED_ACCESS
108 select HAVE_EXIT_THREAD
109 select HAVE_FENTRY if X86_64
110 select HAVE_FTRACE_MCOUNT_RECORD
111 select HAVE_FUNCTION_GRAPH_FP_TEST
112 select HAVE_FUNCTION_GRAPH_TRACER
113 select HAVE_FUNCTION_TRACER
114 select HAVE_GENERIC_DMA_COHERENT if X86_32
115 select HAVE_HW_BREAKPOINT
117 select HAVE_IOREMAP_PROT
118 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
119 select HAVE_IRQ_TIME_ACCOUNTING
120 select HAVE_KERNEL_BZIP2
121 select HAVE_KERNEL_GZIP
122 select HAVE_KERNEL_LZ4
123 select HAVE_KERNEL_LZMA
124 select HAVE_KERNEL_LZO
125 select HAVE_KERNEL_XZ
127 select HAVE_KPROBES_ON_FTRACE
128 select HAVE_KRETPROBES
130 select HAVE_LIVEPATCH if X86_64
132 select HAVE_MEMBLOCK_NODE_MAP
133 select HAVE_MIXED_BREAKPOINTS_REGS
136 select HAVE_OPTPROBES
137 select HAVE_PCSPKR_PLATFORM
138 select HAVE_PERF_EVENTS
139 select HAVE_PERF_EVENTS_NMI
140 select HAVE_PERF_REGS
141 select HAVE_PERF_USER_STACK_DUMP
142 select HAVE_REGS_AND_STACK_ACCESS_API
143 select HAVE_SYSCALL_TRACEPOINTS
144 select HAVE_UID16 if X86_32 || IA32_EMULATION
145 select HAVE_UNSTABLE_SCHED_CLOCK
146 select HAVE_USER_RETURN_NOTIFIER
147 select IRQ_FORCED_THREADING
148 select MODULES_USE_ELF_RELA if X86_64
149 select MODULES_USE_ELF_REL if X86_32
150 select OLD_SIGACTION if X86_32
151 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
156 select SYSCTL_EXCEPTION_TRACE
157 select USER_STACKTRACE_SUPPORT
159 select X86_DEV_DMA_OPS if X86_64
160 select X86_FEATURE_NAMES if PROC_FS
161 select HAVE_STACK_VALIDATION if X86_64
162 select ARCH_USES_HIGH_VMA_FLAGS if X86_INTEL_MEMORY_PROTECTION_KEYS
163 select ARCH_HAS_PKEYS if X86_INTEL_MEMORY_PROTECTION_KEYS
165 config INSTRUCTION_DECODER
167 depends on KPROBES || PERF_EVENTS || UPROBES
171 default "elf32-i386" if X86_32
172 default "elf64-x86-64" if X86_64
174 config ARCH_DEFCONFIG
176 default "arch/x86/configs/i386_defconfig" if X86_32
177 default "arch/x86/configs/x86_64_defconfig" if X86_64
179 config LOCKDEP_SUPPORT
182 config STACKTRACE_SUPPORT
188 config ARCH_MMAP_RND_BITS_MIN
192 config ARCH_MMAP_RND_BITS_MAX
196 config ARCH_MMAP_RND_COMPAT_BITS_MIN
199 config ARCH_MMAP_RND_COMPAT_BITS_MAX
205 config NEED_DMA_MAP_STATE
207 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
209 config NEED_SG_DMA_LENGTH
212 config GENERIC_ISA_DMA
214 depends on ISA_DMA_API
219 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
221 config GENERIC_BUG_RELATIVE_POINTERS
224 config GENERIC_HWEIGHT
227 config ARCH_MAY_HAVE_PC_FDC
229 depends on ISA_DMA_API
231 config RWSEM_XCHGADD_ALGORITHM
234 config GENERIC_CALIBRATE_DELAY
237 config ARCH_HAS_CPU_RELAX
240 config ARCH_HAS_CACHE_LINE_SIZE
243 config HAVE_SETUP_PER_CPU_AREA
246 config NEED_PER_CPU_EMBED_FIRST_CHUNK
249 config NEED_PER_CPU_PAGE_FIRST_CHUNK
252 config ARCH_HIBERNATION_POSSIBLE
255 config ARCH_SUSPEND_POSSIBLE
258 config ARCH_WANT_HUGE_PMD_SHARE
261 config ARCH_WANT_GENERAL_HUGETLB
270 config ARCH_SUPPORTS_OPTIMIZED_INLINING
273 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
276 config KASAN_SHADOW_OFFSET
279 default 0xdffffc0000000000
281 config HAVE_INTEL_TXT
283 depends on INTEL_IOMMU && ACPI
287 depends on X86_32 && SMP
291 depends on X86_64 && SMP
293 config X86_32_LAZY_GS
295 depends on X86_32 && !CC_STACKPROTECTOR
297 config ARCH_SUPPORTS_UPROBES
300 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
479 depends on X86_X2APIC
482 This option is needed in order to support SGI Ultraviolet systems.
483 If you don't have one of these, you should say N here.
485 # Following is an alphabetically sorted list of 32 bit extended platforms
486 # Please maintain the alphabetic order if and when there are additions
489 bool "Goldfish (Virtual Platform)"
490 depends on X86_EXTENDED_PLATFORM
492 Enable support for the Goldfish virtual platform used primarily
493 for Android development. Unless you are building for the Android
494 Goldfish emulator say N here.
497 bool "CE4100 TV platform"
499 depends on PCI_GODIRECT
500 depends on X86_IO_APIC
502 depends on X86_EXTENDED_PLATFORM
503 select X86_REBOOTFIXUPS
505 select OF_EARLY_FLATTREE
507 Select for the Intel CE media processor (CE4100) SOC.
508 This option compiles in support for the CE4100 SOC for settop
509 boxes and media devices.
512 bool "Intel MID platform support"
513 depends on X86_EXTENDED_PLATFORM
514 depends on X86_PLATFORM_DEVICES
516 depends on X86_64 || (PCI_GOANY && X86_32)
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. The interface used is documented
782 in the HPET spec, revision 1.
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 source "arch/x86/events/Kconfig"
1044 config X86_LEGACY_VM86
1045 bool "Legacy VM86 support"
1049 This option allows user programs to put the CPU into V8086
1050 mode, which is an 80286-era approximation of 16-bit real mode.
1052 Some very old versions of X and/or vbetool require this option
1053 for user mode setting. Similarly, DOSEMU will use it if
1054 available to accelerate real mode DOS programs. However, any
1055 recent version of DOSEMU, X, or vbetool should be fully
1056 functional even without kernel VM86 support, as they will all
1057 fall back to software emulation. Nevertheless, if you are using
1058 a 16-bit DOS program where 16-bit performance matters, vm86
1059 mode might be faster than emulation and you might want to
1062 Note that any app that works on a 64-bit kernel is unlikely to
1063 need this option, as 64-bit kernels don't, and can't, support
1064 V8086 mode. This option is also unrelated to 16-bit protected
1065 mode and is not needed to run most 16-bit programs under Wine.
1067 Enabling this option increases the complexity of the kernel
1068 and slows down exception handling a tiny bit.
1070 If unsure, say N here.
1074 default X86_LEGACY_VM86
1077 bool "Enable support for 16-bit segments" if EXPERT
1079 depends on MODIFY_LDT_SYSCALL
1081 This option is required by programs like Wine to run 16-bit
1082 protected mode legacy code on x86 processors. Disabling
1083 this option saves about 300 bytes on i386, or around 6K text
1084 plus 16K runtime memory on x86-64,
1088 depends on X86_16BIT && X86_32
1092 depends on X86_16BIT && X86_64
1094 config X86_VSYSCALL_EMULATION
1095 bool "Enable vsyscall emulation" if EXPERT
1099 This enables emulation of the legacy vsyscall page. Disabling
1100 it is roughly equivalent to booting with vsyscall=none, except
1101 that it will also disable the helpful warning if a program
1102 tries to use a vsyscall. With this option set to N, offending
1103 programs will just segfault, citing addresses of the form
1106 This option is required by many programs built before 2013, and
1107 care should be used even with newer programs if set to N.
1109 Disabling this option saves about 7K of kernel size and
1110 possibly 4K of additional runtime pagetable memory.
1113 tristate "Toshiba Laptop support"
1116 This adds a driver to safely access the System Management Mode of
1117 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1118 not work on models with a Phoenix BIOS. The System Management Mode
1119 is used to set the BIOS and power saving options on Toshiba portables.
1121 For information on utilities to make use of this driver see the
1122 Toshiba Linux utilities web site at:
1123 <http://www.buzzard.org.uk/toshiba/>.
1125 Say Y if you intend to run this kernel on a Toshiba portable.
1129 tristate "Dell i8k legacy laptop support"
1131 select SENSORS_DELL_SMM
1133 This option enables legacy /proc/i8k userspace interface in hwmon
1134 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1135 temperature and allows controlling fan speeds of Dell laptops via
1136 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1137 it reports also power and hotkey status. For fan speed control is
1138 needed userspace package i8kutils.
1140 Say Y if you intend to run this kernel on old Dell laptops or want to
1141 use userspace package i8kutils.
1144 config X86_REBOOTFIXUPS
1145 bool "Enable X86 board specific fixups for reboot"
1148 This enables chipset and/or board specific fixups to be done
1149 in order to get reboot to work correctly. This is only needed on
1150 some combinations of hardware and BIOS. The symptom, for which
1151 this config is intended, is when reboot ends with a stalled/hung
1154 Currently, the only fixup is for the Geode machines using
1155 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1157 Say Y if you want to enable the fixup. Currently, it's safe to
1158 enable this option even if you don't need it.
1162 bool "CPU microcode loading support"
1164 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1167 If you say Y here, you will be able to update the microcode on
1168 Intel and AMD processors. The Intel support is for the IA32 family,
1169 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1170 AMD support is for families 0x10 and later. You will obviously need
1171 the actual microcode binary data itself which is not shipped with
1174 The preferred method to load microcode from a detached initrd is described
1175 in Documentation/x86/early-microcode.txt. For that you need to enable
1176 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1177 initrd for microcode blobs.
1179 In addition, you can build-in the microcode into the kernel. For that you
1180 need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
1181 to the CONFIG_EXTRA_FIRMWARE config option.
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
1720 config X86_INTEL_MEMORY_PROTECTION_KEYS
1721 prompt "Intel Memory Protection Keys"
1723 # Note: only available in 64-bit mode
1724 depends on CPU_SUP_INTEL && X86_64
1726 Memory Protection Keys provides a mechanism for enforcing
1727 page-based protections, but without requiring modification of the
1728 page tables when an application changes protection domains.
1730 For details, see Documentation/x86/protection-keys.txt
1735 bool "EFI runtime service support"
1738 select EFI_RUNTIME_WRAPPERS
1740 This enables the kernel to use EFI runtime services that are
1741 available (such as the EFI variable services).
1743 This option is only useful on systems that have EFI firmware.
1744 In addition, you should use the latest ELILO loader available
1745 at <http://elilo.sourceforge.net> in order to take advantage
1746 of EFI runtime services. However, even with this option, the
1747 resultant kernel should continue to boot on existing non-EFI
1751 bool "EFI stub support"
1752 depends on EFI && !X86_USE_3DNOW
1755 This kernel feature allows a bzImage to be loaded directly
1756 by EFI firmware without the use of a bootloader.
1758 See Documentation/efi-stub.txt for more information.
1761 bool "EFI mixed-mode support"
1762 depends on EFI_STUB && X86_64
1764 Enabling this feature allows a 64-bit kernel to be booted
1765 on a 32-bit firmware, provided that your CPU supports 64-bit
1768 Note that it is not possible to boot a mixed-mode enabled
1769 kernel via the EFI boot stub - a bootloader that supports
1770 the EFI handover protocol must be used.
1776 prompt "Enable seccomp to safely compute untrusted bytecode"
1778 This kernel feature is useful for number crunching applications
1779 that may need to compute untrusted bytecode during their
1780 execution. By using pipes or other transports made available to
1781 the process as file descriptors supporting the read/write
1782 syscalls, it's possible to isolate those applications in
1783 their own address space using seccomp. Once seccomp is
1784 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1785 and the task is only allowed to execute a few safe syscalls
1786 defined by each seccomp mode.
1788 If unsure, say Y. Only embedded should say N here.
1790 source kernel/Kconfig.hz
1793 bool "kexec system call"
1796 kexec is a system call that implements the ability to shutdown your
1797 current kernel, and to start another kernel. It is like a reboot
1798 but it is independent of the system firmware. And like a reboot
1799 you can start any kernel with it, not just Linux.
1801 The name comes from the similarity to the exec system call.
1803 It is an ongoing process to be certain the hardware in a machine
1804 is properly shutdown, so do not be surprised if this code does not
1805 initially work for you. As of this writing the exact hardware
1806 interface is strongly in flux, so no good recommendation can be
1810 bool "kexec file based system call"
1815 depends on CRYPTO_SHA256=y
1817 This is new version of kexec system call. This system call is
1818 file based and takes file descriptors as system call argument
1819 for kernel and initramfs as opposed to list of segments as
1820 accepted by previous system call.
1822 config KEXEC_VERIFY_SIG
1823 bool "Verify kernel signature during kexec_file_load() syscall"
1824 depends on KEXEC_FILE
1826 This option makes kernel signature verification mandatory for
1827 the kexec_file_load() syscall.
1829 In addition to that option, you need to enable signature
1830 verification for the corresponding kernel image type being
1831 loaded in order for this to work.
1833 config KEXEC_BZIMAGE_VERIFY_SIG
1834 bool "Enable bzImage signature verification support"
1835 depends on KEXEC_VERIFY_SIG
1836 depends on SIGNED_PE_FILE_VERIFICATION
1837 select SYSTEM_TRUSTED_KEYRING
1839 Enable bzImage signature verification support.
1842 bool "kernel crash dumps"
1843 depends on X86_64 || (X86_32 && HIGHMEM)
1845 Generate crash dump after being started by kexec.
1846 This should be normally only set in special crash dump kernels
1847 which are loaded in the main kernel with kexec-tools into
1848 a specially reserved region and then later executed after
1849 a crash by kdump/kexec. The crash dump kernel must be compiled
1850 to a memory address not used by the main kernel or BIOS using
1851 PHYSICAL_START, or it must be built as a relocatable image
1852 (CONFIG_RELOCATABLE=y).
1853 For more details see Documentation/kdump/kdump.txt
1857 depends on KEXEC && HIBERNATION
1859 Jump between original kernel and kexeced kernel and invoke
1860 code in physical address mode via KEXEC
1862 config PHYSICAL_START
1863 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1866 This gives the physical address where the kernel is loaded.
1868 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1869 bzImage will decompress itself to above physical address and
1870 run from there. Otherwise, bzImage will run from the address where
1871 it has been loaded by the boot loader and will ignore above physical
1874 In normal kdump cases one does not have to set/change this option
1875 as now bzImage can be compiled as a completely relocatable image
1876 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1877 address. This option is mainly useful for the folks who don't want
1878 to use a bzImage for capturing the crash dump and want to use a
1879 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1880 to be specifically compiled to run from a specific memory area
1881 (normally a reserved region) and this option comes handy.
1883 So if you are using bzImage for capturing the crash dump,
1884 leave the value here unchanged to 0x1000000 and set
1885 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1886 for capturing the crash dump change this value to start of
1887 the reserved region. In other words, it can be set based on
1888 the "X" value as specified in the "crashkernel=YM@XM"
1889 command line boot parameter passed to the panic-ed
1890 kernel. Please take a look at Documentation/kdump/kdump.txt
1891 for more details about crash dumps.
1893 Usage of bzImage for capturing the crash dump is recommended as
1894 one does not have to build two kernels. Same kernel can be used
1895 as production kernel and capture kernel. Above option should have
1896 gone away after relocatable bzImage support is introduced. But it
1897 is present because there are users out there who continue to use
1898 vmlinux for dump capture. This option should go away down the
1901 Don't change this unless you know what you are doing.
1904 bool "Build a relocatable kernel"
1907 This builds a kernel image that retains relocation information
1908 so it can be loaded someplace besides the default 1MB.
1909 The relocations tend to make the kernel binary about 10% larger,
1910 but are discarded at runtime.
1912 One use is for the kexec on panic case where the recovery kernel
1913 must live at a different physical address than the primary
1916 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1917 it has been loaded at and the compile time physical address
1918 (CONFIG_PHYSICAL_START) is used as the minimum location.
1920 config RANDOMIZE_BASE
1921 bool "Randomize the address of the kernel image (KASLR)"
1922 depends on RELOCATABLE
1925 In support of Kernel Address Space Layout Randomization (KASLR),
1926 this randomizes the physical address at which the kernel image
1927 is decompressed and the virtual address where the kernel
1928 image is mapped, as a security feature that deters exploit
1929 attempts relying on knowledge of the location of kernel
1932 The kernel physical and virtual address can be randomized
1933 from 16MB up to 1GB on 64-bit and 512MB on 32-bit. (Note that
1934 using RANDOMIZE_BASE reduces the memory space available to
1935 kernel modules from 1.5GB to 1GB.)
1937 Entropy is generated using the RDRAND instruction if it is
1938 supported. If RDTSC is supported, its value is mixed into
1939 the entropy pool as well. If neither RDRAND nor RDTSC are
1940 supported, then entropy is read from the i8254 timer.
1942 Since the kernel is built using 2GB addressing, and
1943 PHYSICAL_ALIGN must be at a minimum of 2MB, only 10 bits of
1944 entropy is theoretically possible. Currently, with the
1945 default value for PHYSICAL_ALIGN and due to page table
1946 layouts, 64-bit uses 9 bits of entropy and 32-bit uses 8 bits.
1948 If CONFIG_HIBERNATE is also enabled, KASLR is disabled at boot
1949 time. To enable it, boot with "kaslr" on the kernel command
1950 line (which will also disable hibernation).
1954 # Relocation on x86 needs some additional build support
1955 config X86_NEED_RELOCS
1957 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1959 config PHYSICAL_ALIGN
1960 hex "Alignment value to which kernel should be aligned"
1962 range 0x2000 0x1000000 if X86_32
1963 range 0x200000 0x1000000 if X86_64
1965 This value puts the alignment restrictions on physical address
1966 where kernel is loaded and run from. Kernel is compiled for an
1967 address which meets above alignment restriction.
1969 If bootloader loads the kernel at a non-aligned address and
1970 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1971 address aligned to above value and run from there.
1973 If bootloader loads the kernel at a non-aligned address and
1974 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1975 load address and decompress itself to the address it has been
1976 compiled for and run from there. The address for which kernel is
1977 compiled already meets above alignment restrictions. Hence the
1978 end result is that kernel runs from a physical address meeting
1979 above alignment restrictions.
1981 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1982 this value must be a multiple of 0x200000.
1984 Don't change this unless you know what you are doing.
1987 bool "Support for hot-pluggable CPUs"
1990 Say Y here to allow turning CPUs off and on. CPUs can be
1991 controlled through /sys/devices/system/cpu.
1992 ( Note: power management support will enable this option
1993 automatically on SMP systems. )
1994 Say N if you want to disable CPU hotplug.
1996 config BOOTPARAM_HOTPLUG_CPU0
1997 bool "Set default setting of cpu0_hotpluggable"
1999 depends on HOTPLUG_CPU
2001 Set whether default state of cpu0_hotpluggable is on or off.
2003 Say Y here to enable CPU0 hotplug by default. If this switch
2004 is turned on, there is no need to give cpu0_hotplug kernel
2005 parameter and the CPU0 hotplug feature is enabled by default.
2007 Please note: there are two known CPU0 dependencies if you want
2008 to enable the CPU0 hotplug feature either by this switch or by
2009 cpu0_hotplug kernel parameter.
2011 First, resume from hibernate or suspend always starts from CPU0.
2012 So hibernate and suspend are prevented if CPU0 is offline.
2014 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2015 offline if any interrupt can not migrate out of CPU0. There may
2016 be other CPU0 dependencies.
2018 Please make sure the dependencies are under your control before
2019 you enable this feature.
2021 Say N if you don't want to enable CPU0 hotplug feature by default.
2022 You still can enable the CPU0 hotplug feature at boot by kernel
2023 parameter cpu0_hotplug.
2025 config DEBUG_HOTPLUG_CPU0
2027 prompt "Debug CPU0 hotplug"
2028 depends on HOTPLUG_CPU
2030 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2031 soon as possible and boots up userspace with CPU0 offlined. User
2032 can online CPU0 back after boot time.
2034 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2035 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2036 compilation or giving cpu0_hotplug kernel parameter at boot.
2042 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2043 depends on X86_32 || IA32_EMULATION
2045 Certain buggy versions of glibc will crash if they are
2046 presented with a 32-bit vDSO that is not mapped at the address
2047 indicated in its segment table.
2049 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2050 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2051 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2052 the only released version with the bug, but OpenSUSE 9
2053 contains a buggy "glibc 2.3.2".
2055 The symptom of the bug is that everything crashes on startup, saying:
2056 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2058 Saying Y here changes the default value of the vdso32 boot
2059 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2060 This works around the glibc bug but hurts performance.
2062 If unsure, say N: if you are compiling your own kernel, you
2063 are unlikely to be using a buggy version of glibc.
2066 prompt "vsyscall table for legacy applications"
2068 default LEGACY_VSYSCALL_EMULATE
2070 Legacy user code that does not know how to find the vDSO expects
2071 to be able to issue three syscalls by calling fixed addresses in
2072 kernel space. Since this location is not randomized with ASLR,
2073 it can be used to assist security vulnerability exploitation.
2075 This setting can be changed at boot time via the kernel command
2076 line parameter vsyscall=[native|emulate|none].
2078 On a system with recent enough glibc (2.14 or newer) and no
2079 static binaries, you can say None without a performance penalty
2080 to improve security.
2082 If unsure, select "Emulate".
2084 config LEGACY_VSYSCALL_NATIVE
2087 Actual executable code is located in the fixed vsyscall
2088 address mapping, implementing time() efficiently. Since
2089 this makes the mapping executable, it can be used during
2090 security vulnerability exploitation (traditionally as
2091 ROP gadgets). This configuration is not recommended.
2093 config LEGACY_VSYSCALL_EMULATE
2096 The kernel traps and emulates calls into the fixed
2097 vsyscall address mapping. This makes the mapping
2098 non-executable, but it still contains known contents,
2099 which could be used in certain rare security vulnerability
2100 exploits. This configuration is recommended when userspace
2101 still uses the vsyscall area.
2103 config LEGACY_VSYSCALL_NONE
2106 There will be no vsyscall mapping at all. This will
2107 eliminate any risk of ASLR bypass due to the vsyscall
2108 fixed address mapping. Attempts to use the vsyscalls
2109 will be reported to dmesg, so that either old or
2110 malicious userspace programs can be identified.
2115 bool "Built-in kernel command line"
2117 Allow for specifying boot arguments to the kernel at
2118 build time. On some systems (e.g. embedded ones), it is
2119 necessary or convenient to provide some or all of the
2120 kernel boot arguments with the kernel itself (that is,
2121 to not rely on the boot loader to provide them.)
2123 To compile command line arguments into the kernel,
2124 set this option to 'Y', then fill in the
2125 boot arguments in CONFIG_CMDLINE.
2127 Systems with fully functional boot loaders (i.e. non-embedded)
2128 should leave this option set to 'N'.
2131 string "Built-in kernel command string"
2132 depends on CMDLINE_BOOL
2135 Enter arguments here that should be compiled into the kernel
2136 image and used at boot time. If the boot loader provides a
2137 command line at boot time, it is appended to this string to
2138 form the full kernel command line, when the system boots.
2140 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2141 change this behavior.
2143 In most cases, the command line (whether built-in or provided
2144 by the boot loader) should specify the device for the root
2147 config CMDLINE_OVERRIDE
2148 bool "Built-in command line overrides boot loader arguments"
2149 depends on CMDLINE_BOOL
2151 Set this option to 'Y' to have the kernel ignore the boot loader
2152 command line, and use ONLY the built-in command line.
2154 This is used to work around broken boot loaders. This should
2155 be set to 'N' under normal conditions.
2157 config MODIFY_LDT_SYSCALL
2158 bool "Enable the LDT (local descriptor table)" if EXPERT
2161 Linux can allow user programs to install a per-process x86
2162 Local Descriptor Table (LDT) using the modify_ldt(2) system
2163 call. This is required to run 16-bit or segmented code such as
2164 DOSEMU or some Wine programs. It is also used by some very old
2165 threading libraries.
2167 Enabling this feature adds a small amount of overhead to
2168 context switches and increases the low-level kernel attack
2169 surface. Disabling it removes the modify_ldt(2) system call.
2171 Saying 'N' here may make sense for embedded or server kernels.
2173 source "kernel/livepatch/Kconfig"
2177 config ARCH_ENABLE_MEMORY_HOTPLUG
2179 depends on X86_64 || (X86_32 && HIGHMEM)
2181 config ARCH_ENABLE_MEMORY_HOTREMOVE
2183 depends on MEMORY_HOTPLUG
2185 config USE_PERCPU_NUMA_NODE_ID
2189 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2191 depends on X86_64 || X86_PAE
2193 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2195 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2197 menu "Power management and ACPI options"
2199 config ARCH_HIBERNATION_HEADER
2201 depends on X86_64 && HIBERNATION
2203 source "kernel/power/Kconfig"
2205 source "drivers/acpi/Kconfig"
2207 source "drivers/sfi/Kconfig"
2214 tristate "APM (Advanced Power Management) BIOS support"
2215 depends on X86_32 && PM_SLEEP
2217 APM is a BIOS specification for saving power using several different
2218 techniques. This is mostly useful for battery powered laptops with
2219 APM compliant BIOSes. If you say Y here, the system time will be
2220 reset after a RESUME operation, the /proc/apm device will provide
2221 battery status information, and user-space programs will receive
2222 notification of APM "events" (e.g. battery status change).
2224 If you select "Y" here, you can disable actual use of the APM
2225 BIOS by passing the "apm=off" option to the kernel at boot time.
2227 Note that the APM support is almost completely disabled for
2228 machines with more than one CPU.
2230 In order to use APM, you will need supporting software. For location
2231 and more information, read <file:Documentation/power/apm-acpi.txt>
2232 and the Battery Powered Linux mini-HOWTO, available from
2233 <http://www.tldp.org/docs.html#howto>.
2235 This driver does not spin down disk drives (see the hdparm(8)
2236 manpage ("man 8 hdparm") for that), and it doesn't turn off
2237 VESA-compliant "green" monitors.
2239 This driver does not support the TI 4000M TravelMate and the ACER
2240 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2241 desktop machines also don't have compliant BIOSes, and this driver
2242 may cause those machines to panic during the boot phase.
2244 Generally, if you don't have a battery in your machine, there isn't
2245 much point in using this driver and you should say N. If you get
2246 random kernel OOPSes or reboots that don't seem to be related to
2247 anything, try disabling/enabling this option (or disabling/enabling
2250 Some other things you should try when experiencing seemingly random,
2253 1) make sure that you have enough swap space and that it is
2255 2) pass the "no-hlt" option to the kernel
2256 3) switch on floating point emulation in the kernel and pass
2257 the "no387" option to the kernel
2258 4) pass the "floppy=nodma" option to the kernel
2259 5) pass the "mem=4M" option to the kernel (thereby disabling
2260 all but the first 4 MB of RAM)
2261 6) make sure that the CPU is not over clocked.
2262 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2263 8) disable the cache from your BIOS settings
2264 9) install a fan for the video card or exchange video RAM
2265 10) install a better fan for the CPU
2266 11) exchange RAM chips
2267 12) exchange the motherboard.
2269 To compile this driver as a module, choose M here: the
2270 module will be called apm.
2274 config APM_IGNORE_USER_SUSPEND
2275 bool "Ignore USER SUSPEND"
2277 This option will ignore USER SUSPEND requests. On machines with a
2278 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2279 series notebooks, it is necessary to say Y because of a BIOS bug.
2281 config APM_DO_ENABLE
2282 bool "Enable PM at boot time"
2284 Enable APM features at boot time. From page 36 of the APM BIOS
2285 specification: "When disabled, the APM BIOS does not automatically
2286 power manage devices, enter the Standby State, enter the Suspend
2287 State, or take power saving steps in response to CPU Idle calls."
2288 This driver will make CPU Idle calls when Linux is idle (unless this
2289 feature is turned off -- see "Do CPU IDLE calls", below). This
2290 should always save battery power, but more complicated APM features
2291 will be dependent on your BIOS implementation. You may need to turn
2292 this option off if your computer hangs at boot time when using APM
2293 support, or if it beeps continuously instead of suspending. Turn
2294 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2295 T400CDT. This is off by default since most machines do fine without
2300 bool "Make CPU Idle calls when idle"
2302 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2303 On some machines, this can activate improved power savings, such as
2304 a slowed CPU clock rate, when the machine is idle. These idle calls
2305 are made after the idle loop has run for some length of time (e.g.,
2306 333 mS). On some machines, this will cause a hang at boot time or
2307 whenever the CPU becomes idle. (On machines with more than one CPU,
2308 this option does nothing.)
2310 config APM_DISPLAY_BLANK
2311 bool "Enable console blanking using APM"
2313 Enable console blanking using the APM. Some laptops can use this to
2314 turn off the LCD backlight when the screen blanker of the Linux
2315 virtual console blanks the screen. Note that this is only used by
2316 the virtual console screen blanker, and won't turn off the backlight
2317 when using the X Window system. This also doesn't have anything to
2318 do with your VESA-compliant power-saving monitor. Further, this
2319 option doesn't work for all laptops -- it might not turn off your
2320 backlight at all, or it might print a lot of errors to the console,
2321 especially if you are using gpm.
2323 config APM_ALLOW_INTS
2324 bool "Allow interrupts during APM BIOS calls"
2326 Normally we disable external interrupts while we are making calls to
2327 the APM BIOS as a measure to lessen the effects of a badly behaving
2328 BIOS implementation. The BIOS should reenable interrupts if it
2329 needs to. Unfortunately, some BIOSes do not -- especially those in
2330 many of the newer IBM Thinkpads. If you experience hangs when you
2331 suspend, try setting this to Y. Otherwise, say N.
2335 source "drivers/cpufreq/Kconfig"
2337 source "drivers/cpuidle/Kconfig"
2339 source "drivers/idle/Kconfig"
2344 menu "Bus options (PCI etc.)"
2350 Find out whether you have a PCI motherboard. PCI is the name of a
2351 bus system, i.e. the way the CPU talks to the other stuff inside
2352 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2353 VESA. If you have PCI, say Y, otherwise N.
2356 prompt "PCI access mode"
2357 depends on X86_32 && PCI
2360 On PCI systems, the BIOS can be used to detect the PCI devices and
2361 determine their configuration. However, some old PCI motherboards
2362 have BIOS bugs and may crash if this is done. Also, some embedded
2363 PCI-based systems don't have any BIOS at all. Linux can also try to
2364 detect the PCI hardware directly without using the BIOS.
2366 With this option, you can specify how Linux should detect the
2367 PCI devices. If you choose "BIOS", the BIOS will be used,
2368 if you choose "Direct", the BIOS won't be used, and if you
2369 choose "MMConfig", then PCI Express MMCONFIG will be used.
2370 If you choose "Any", the kernel will try MMCONFIG, then the
2371 direct access method and falls back to the BIOS if that doesn't
2372 work. If unsure, go with the default, which is "Any".
2377 config PCI_GOMMCONFIG
2394 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2396 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2399 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2403 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2407 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2411 depends on PCI && XEN
2419 bool "Support mmconfig PCI config space access"
2420 depends on X86_64 && PCI && ACPI
2422 config PCI_CNB20LE_QUIRK
2423 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2426 Read the PCI windows out of the CNB20LE host bridge. This allows
2427 PCI hotplug to work on systems with the CNB20LE chipset which do
2430 There's no public spec for this chipset, and this functionality
2431 is known to be incomplete.
2433 You should say N unless you know you need this.
2435 source "drivers/pci/Kconfig"
2437 # x86_64 have no ISA slots, but can have ISA-style DMA.
2439 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2442 Enables ISA-style DMA support for devices requiring such controllers.
2450 Find out whether you have ISA slots on your motherboard. ISA is the
2451 name of a bus system, i.e. the way the CPU talks to the other stuff
2452 inside your box. Other bus systems are PCI, EISA, MicroChannel
2453 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2454 newer boards don't support it. If you have ISA, say Y, otherwise N.
2460 The Extended Industry Standard Architecture (EISA) bus was
2461 developed as an open alternative to the IBM MicroChannel bus.
2463 The EISA bus provided some of the features of the IBM MicroChannel
2464 bus while maintaining backward compatibility with cards made for
2465 the older ISA bus. The EISA bus saw limited use between 1988 and
2466 1995 when it was made obsolete by the PCI bus.
2468 Say Y here if you are building a kernel for an EISA-based machine.
2472 source "drivers/eisa/Kconfig"
2475 tristate "NatSemi SCx200 support"
2477 This provides basic support for National Semiconductor's
2478 (now AMD's) Geode processors. The driver probes for the
2479 PCI-IDs of several on-chip devices, so its a good dependency
2480 for other scx200_* drivers.
2482 If compiled as a module, the driver is named scx200.
2484 config SCx200HR_TIMER
2485 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2489 This driver provides a clocksource built upon the on-chip
2490 27MHz high-resolution timer. Its also a workaround for
2491 NSC Geode SC-1100's buggy TSC, which loses time when the
2492 processor goes idle (as is done by the scheduler). The
2493 other workaround is idle=poll boot option.
2496 bool "One Laptop Per Child support"
2503 Add support for detecting the unique features of the OLPC
2507 bool "OLPC XO-1 Power Management"
2508 depends on OLPC && MFD_CS5535 && PM_SLEEP
2511 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2514 bool "OLPC XO-1 Real Time Clock"
2515 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2517 Add support for the XO-1 real time clock, which can be used as a
2518 programmable wakeup source.
2521 bool "OLPC XO-1 SCI extras"
2522 depends on OLPC && OLPC_XO1_PM
2528 Add support for SCI-based features of the OLPC XO-1 laptop:
2529 - EC-driven system wakeups
2533 - AC adapter status updates
2534 - Battery status updates
2536 config OLPC_XO15_SCI
2537 bool "OLPC XO-1.5 SCI extras"
2538 depends on OLPC && ACPI
2541 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2542 - EC-driven system wakeups
2543 - AC adapter status updates
2544 - Battery status updates
2547 bool "PCEngines ALIX System Support (LED setup)"
2550 This option enables system support for the PCEngines ALIX.
2551 At present this just sets up LEDs for GPIO control on
2552 ALIX2/3/6 boards. However, other system specific setup should
2555 Note: You must still enable the drivers for GPIO and LED support
2556 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2558 Note: You have to set alix.force=1 for boards with Award BIOS.
2561 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2564 This option enables system support for the Soekris Engineering net5501.
2567 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2571 This option enables system support for the Traverse Technologies GEOS.
2574 bool "Technologic Systems TS-5500 platform support"
2576 select CHECK_SIGNATURE
2580 This option enables system support for the Technologic Systems TS-5500.
2586 depends on CPU_SUP_AMD && PCI
2588 source "drivers/pcmcia/Kconfig"
2591 tristate "RapidIO support"
2595 If enabled this option will include drivers and the core
2596 infrastructure code to support RapidIO interconnect devices.
2598 source "drivers/rapidio/Kconfig"
2601 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2603 Firmwares often provide initial graphics framebuffers so the BIOS,
2604 bootloader or kernel can show basic video-output during boot for
2605 user-guidance and debugging. Historically, x86 used the VESA BIOS
2606 Extensions and EFI-framebuffers for this, which are mostly limited
2608 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2609 framebuffers so the new generic system-framebuffer drivers can be
2610 used on x86. If the framebuffer is not compatible with the generic
2611 modes, it is adverticed as fallback platform framebuffer so legacy
2612 drivers like efifb, vesafb and uvesafb can pick it up.
2613 If this option is not selected, all system framebuffers are always
2614 marked as fallback platform framebuffers as usual.
2616 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2617 not be able to pick up generic system framebuffers if this option
2618 is selected. You are highly encouraged to enable simplefb as
2619 replacement if you select this option. simplefb can correctly deal
2620 with generic system framebuffers. But you should still keep vesafb
2621 and others enabled as fallback if a system framebuffer is
2622 incompatible with simplefb.
2629 menu "Executable file formats / Emulations"
2631 source "fs/Kconfig.binfmt"
2633 config IA32_EMULATION
2634 bool "IA32 Emulation"
2637 select COMPAT_BINFMT_ELF
2638 select ARCH_WANT_OLD_COMPAT_IPC
2640 Include code to run legacy 32-bit programs under a
2641 64-bit kernel. You should likely turn this on, unless you're
2642 100% sure that you don't have any 32-bit programs left.
2645 tristate "IA32 a.out support"
2646 depends on IA32_EMULATION
2648 Support old a.out binaries in the 32bit emulation.
2651 bool "x32 ABI for 64-bit mode"
2654 Include code to run binaries for the x32 native 32-bit ABI
2655 for 64-bit processors. An x32 process gets access to the
2656 full 64-bit register file and wide data path while leaving
2657 pointers at 32 bits for smaller memory footprint.
2659 You will need a recent binutils (2.22 or later) with
2660 elf32_x86_64 support enabled to compile a kernel with this
2665 depends on IA32_EMULATION || X86_X32
2668 config COMPAT_FOR_U64_ALIGNMENT
2671 config SYSVIPC_COMPAT
2683 config HAVE_ATOMIC_IOMAP
2687 config X86_DEV_DMA_OPS
2689 depends on X86_64 || STA2X11
2691 config X86_DMA_REMAP
2701 tristate "Volume Management Device Driver"
2704 Adds support for the Intel Volume Management Device (VMD). VMD is a
2705 secondary PCI host bridge that allows PCI Express root ports,
2706 and devices attached to them, to be removed from the default
2707 PCI domain and placed within the VMD domain. This provides
2708 more bus resources than are otherwise possible with a
2709 single domain. If you know your system provides one of these and
2710 has devices attached to it, say Y; if you are not sure, say N.
2712 source "net/Kconfig"
2714 source "drivers/Kconfig"
2716 source "drivers/firmware/Kconfig"
2720 source "arch/x86/Kconfig.debug"
2722 source "security/Kconfig"
2724 source "crypto/Kconfig"
2726 source "arch/x86/kvm/Kconfig"
2728 source "lib/Kconfig"
projects / cascardo / linux.git / blob