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"
512 depends on X86_EXTENDED_PLATFORM
513 depends on X86_PLATFORM_DEVICES
515 depends on X86_64 || (PCI_GOANY && X86_32)
516 depends on X86_IO_APIC
522 select MFD_INTEL_MSIC
524 Select to build a kernel capable of supporting Intel MID (Mobile
525 Internet Device) platform systems which do not have the PCI legacy
526 interfaces. If you are building for a PC class system say N here.
528 Intel MID platforms are based on an Intel processor and chipset which
529 consume less power than most of the x86 derivatives.
531 config X86_INTEL_QUARK
532 bool "Intel Quark platform support"
534 depends on X86_EXTENDED_PLATFORM
535 depends on X86_PLATFORM_DEVICES
539 depends on X86_IO_APIC
544 Select to include support for Quark X1000 SoC.
545 Say Y here if you have a Quark based system such as the Arduino
546 compatible Intel Galileo.
548 config X86_INTEL_LPSS
549 bool "Intel Low Power Subsystem Support"
550 depends on X86 && ACPI
555 Select to build support for Intel Low Power Subsystem such as
556 found on Intel Lynxpoint PCH. Selecting this option enables
557 things like clock tree (common clock framework) and pincontrol
558 which are needed by the LPSS peripheral drivers.
560 config X86_AMD_PLATFORM_DEVICE
561 bool "AMD ACPI2Platform devices support"
566 Select to interpret AMD specific ACPI device to platform device
567 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
568 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
569 implemented under PINCTRL subsystem.
572 tristate "Intel SoC IOSF Sideband support for SoC platforms"
575 This option enables sideband register access support for Intel SoC
576 platforms. On these platforms the IOSF sideband is used in lieu of
577 MSR's for some register accesses, mostly but not limited to thermal
578 and power. Drivers may query the availability of this device to
579 determine if they need the sideband in order to work on these
580 platforms. The sideband is available on the following SoC products.
581 This list is not meant to be exclusive.
586 You should say Y if you are running a kernel on one of these SoC's.
588 config IOSF_MBI_DEBUG
589 bool "Enable IOSF sideband access through debugfs"
590 depends on IOSF_MBI && DEBUG_FS
592 Select this option to expose the IOSF sideband access registers (MCR,
593 MDR, MCRX) through debugfs to write and read register information from
594 different units on the SoC. This is most useful for obtaining device
595 state information for debug and analysis. As this is a general access
596 mechanism, users of this option would have specific knowledge of the
597 device they want to access.
599 If you don't require the option or are in doubt, say N.
602 bool "RDC R-321x SoC"
604 depends on X86_EXTENDED_PLATFORM
606 select X86_REBOOTFIXUPS
608 This option is needed for RDC R-321x system-on-chip, also known
610 If you don't have one of these chips, you should say N here.
612 config X86_32_NON_STANDARD
613 bool "Support non-standard 32-bit SMP architectures"
614 depends on X86_32 && SMP
615 depends on X86_EXTENDED_PLATFORM
617 This option compiles in the bigsmp and STA2X11 default
618 subarchitectures. It is intended for a generic binary
619 kernel. If you select them all, kernel will probe it one by
620 one and will fallback to default.
622 # Alphabetically sorted list of Non standard 32 bit platforms
624 config X86_SUPPORTS_MEMORY_FAILURE
626 # MCE code calls memory_failure():
628 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
629 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
630 depends on X86_64 || !SPARSEMEM
631 select ARCH_SUPPORTS_MEMORY_FAILURE
634 bool "STA2X11 Companion Chip Support"
635 depends on X86_32_NON_STANDARD && PCI
636 select X86_DEV_DMA_OPS
640 select ARCH_REQUIRE_GPIOLIB
643 This adds support for boards based on the STA2X11 IO-Hub,
644 a.k.a. "ConneXt". The chip is used in place of the standard
645 PC chipset, so all "standard" peripherals are missing. If this
646 option is selected the kernel will still be able to boot on
647 standard PC machines.
650 tristate "Eurobraille/Iris poweroff module"
653 The Iris machines from EuroBraille do not have APM or ACPI support
654 to shut themselves down properly. A special I/O sequence is
655 needed to do so, which is what this module does at
658 This is only for Iris machines from EuroBraille.
662 config SCHED_OMIT_FRAME_POINTER
664 prompt "Single-depth WCHAN output"
667 Calculate simpler /proc/<PID>/wchan values. If this option
668 is disabled then wchan values will recurse back to the
669 caller function. This provides more accurate wchan values,
670 at the expense of slightly more scheduling overhead.
672 If in doubt, say "Y".
674 menuconfig HYPERVISOR_GUEST
675 bool "Linux guest support"
677 Say Y here to enable options for running Linux under various hyper-
678 visors. This option enables basic hypervisor detection and platform
681 If you say N, all options in this submenu will be skipped and
682 disabled, and Linux guest support won't be built in.
687 bool "Enable paravirtualization code"
689 This changes the kernel so it can modify itself when it is run
690 under a hypervisor, potentially improving performance significantly
691 over full virtualization. However, when run without a hypervisor
692 the kernel is theoretically slower and slightly larger.
694 config PARAVIRT_DEBUG
695 bool "paravirt-ops debugging"
696 depends on PARAVIRT && DEBUG_KERNEL
698 Enable to debug paravirt_ops internals. Specifically, BUG if
699 a paravirt_op is missing when it is called.
701 config PARAVIRT_SPINLOCKS
702 bool "Paravirtualization layer for spinlocks"
703 depends on PARAVIRT && SMP
704 select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS
706 Paravirtualized spinlocks allow a pvops backend to replace the
707 spinlock implementation with something virtualization-friendly
708 (for example, block the virtual CPU rather than spinning).
710 It has a minimal impact on native kernels and gives a nice performance
711 benefit on paravirtualized KVM / Xen kernels.
713 If you are unsure how to answer this question, answer Y.
715 config QUEUED_LOCK_STAT
716 bool "Paravirt queued spinlock statistics"
717 depends on PARAVIRT_SPINLOCKS && DEBUG_FS && QUEUED_SPINLOCKS
719 Enable the collection of statistical data on the slowpath
720 behavior of paravirtualized queued spinlocks and report
723 source "arch/x86/xen/Kconfig"
726 bool "KVM Guest support (including kvmclock)"
728 select PARAVIRT_CLOCK
731 This option enables various optimizations for running under the KVM
732 hypervisor. It includes a paravirtualized clock, so that instead
733 of relying on a PIT (or probably other) emulation by the
734 underlying device model, the host provides the guest with
735 timing infrastructure such as time of day, and system time
738 bool "Enable debug information for KVM Guests in debugfs"
739 depends on KVM_GUEST && DEBUG_FS
742 This option enables collection of various statistics for KVM guest.
743 Statistics are displayed in debugfs filesystem. Enabling this option
744 may incur significant overhead.
746 source "arch/x86/lguest/Kconfig"
748 config PARAVIRT_TIME_ACCOUNTING
749 bool "Paravirtual steal time accounting"
753 Select this option to enable fine granularity task steal time
754 accounting. Time spent executing other tasks in parallel with
755 the current vCPU is discounted from the vCPU power. To account for
756 that, there can be a small performance impact.
758 If in doubt, say N here.
760 config PARAVIRT_CLOCK
763 endif #HYPERVISOR_GUEST
768 source "arch/x86/Kconfig.cpu"
772 prompt "HPET Timer Support" if X86_32
774 Use the IA-PC HPET (High Precision Event Timer) to manage
775 time in preference to the PIT and RTC, if a HPET is
777 HPET is the next generation timer replacing legacy 8254s.
778 The HPET provides a stable time base on SMP
779 systems, unlike the TSC, but it is more expensive to access,
780 as it is off-chip. You can find the HPET spec at
781 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
783 You can safely choose Y here. However, HPET will only be
784 activated if the platform and the BIOS support this feature.
785 Otherwise the 8254 will be used for timing services.
787 Choose N to continue using the legacy 8254 timer.
789 config HPET_EMULATE_RTC
791 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
794 def_bool y if X86_INTEL_MID
795 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
797 depends on X86_INTEL_MID && SFI
799 APB timer is the replacement for 8254, HPET on X86 MID platforms.
800 The APBT provides a stable time base on SMP
801 systems, unlike the TSC, but it is more expensive to access,
802 as it is off-chip. APB timers are always running regardless of CPU
803 C states, they are used as per CPU clockevent device when possible.
805 # Mark as expert because too many people got it wrong.
806 # The code disables itself when not needed.
809 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
810 bool "Enable DMI scanning" if EXPERT
812 Enabled scanning of DMI to identify machine quirks. Say Y
813 here unless you have verified that your setup is not
814 affected by entries in the DMI blacklist. Required by PNP
818 bool "Old AMD GART IOMMU support"
820 depends on X86_64 && PCI && AMD_NB
822 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
823 GART based hardware IOMMUs.
825 The GART supports full DMA access for devices with 32-bit access
826 limitations, on systems with more than 3 GB. This is usually needed
827 for USB, sound, many IDE/SATA chipsets and some other devices.
829 Newer systems typically have a modern AMD IOMMU, supported via
830 the CONFIG_AMD_IOMMU=y config option.
832 In normal configurations this driver is only active when needed:
833 there's more than 3 GB of memory and the system contains a
834 32-bit limited device.
839 bool "IBM Calgary IOMMU support"
841 depends on X86_64 && PCI
843 Support for hardware IOMMUs in IBM's xSeries x366 and x460
844 systems. Needed to run systems with more than 3GB of memory
845 properly with 32-bit PCI devices that do not support DAC
846 (Double Address Cycle). Calgary also supports bus level
847 isolation, where all DMAs pass through the IOMMU. This
848 prevents them from going anywhere except their intended
849 destination. This catches hard-to-find kernel bugs and
850 mis-behaving drivers and devices that do not use the DMA-API
851 properly to set up their DMA buffers. The IOMMU can be
852 turned off at boot time with the iommu=off parameter.
853 Normally the kernel will make the right choice by itself.
856 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
858 prompt "Should Calgary be enabled by default?"
859 depends on CALGARY_IOMMU
861 Should Calgary be enabled by default? if you choose 'y', Calgary
862 will be used (if it exists). If you choose 'n', Calgary will not be
863 used even if it exists. If you choose 'n' and would like to use
864 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
867 # need this always selected by IOMMU for the VIA workaround
871 Support for software bounce buffers used on x86-64 systems
872 which don't have a hardware IOMMU. Using this PCI devices
873 which can only access 32-bits of memory can be used on systems
874 with more than 3 GB of memory.
879 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
882 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
883 depends on X86_64 && SMP && DEBUG_KERNEL
884 select CPUMASK_OFFSTACK
886 Enable maximum number of CPUS and NUMA Nodes for this architecture.
890 int "Maximum number of CPUs" if SMP && !MAXSMP
891 range 2 8 if SMP && X86_32 && !X86_BIGSMP
892 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
893 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
895 default "8192" if MAXSMP
896 default "32" if SMP && X86_BIGSMP
897 default "8" if SMP && X86_32
900 This allows you to specify the maximum number of CPUs which this
901 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
902 supported value is 8192, otherwise the maximum value is 512. The
903 minimum value which makes sense is 2.
905 This is purely to save memory - each supported CPU adds
906 approximately eight kilobytes to the kernel image.
909 bool "SMT (Hyperthreading) scheduler support"
912 SMT scheduler support improves the CPU scheduler's decision making
913 when dealing with Intel Pentium 4 chips with HyperThreading at a
914 cost of slightly increased overhead in some places. If unsure say
919 prompt "Multi-core scheduler support"
922 Multi-core scheduler support improves the CPU scheduler's decision
923 making when dealing with multi-core CPU chips at a cost of slightly
924 increased overhead in some places. If unsure say N here.
926 source "kernel/Kconfig.preempt"
930 depends on !SMP && X86_LOCAL_APIC
933 bool "Local APIC support on uniprocessors" if !PCI_MSI
935 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
937 A local APIC (Advanced Programmable Interrupt Controller) is an
938 integrated interrupt controller in the CPU. If you have a single-CPU
939 system which has a processor with a local APIC, you can say Y here to
940 enable and use it. If you say Y here even though your machine doesn't
941 have a local APIC, then the kernel will still run with no slowdown at
942 all. The local APIC supports CPU-generated self-interrupts (timer,
943 performance counters), and the NMI watchdog which detects hard
947 bool "IO-APIC support on uniprocessors"
948 depends on X86_UP_APIC
950 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
951 SMP-capable replacement for PC-style interrupt controllers. Most
952 SMP systems and many recent uniprocessor systems have one.
954 If you have a single-CPU system with an IO-APIC, you can say Y here
955 to use it. If you say Y here even though your machine doesn't have
956 an IO-APIC, then the kernel will still run with no slowdown at all.
958 config X86_LOCAL_APIC
960 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
961 select IRQ_DOMAIN_HIERARCHY
962 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
966 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
968 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
969 bool "Reroute for broken boot IRQs"
970 depends on X86_IO_APIC
972 This option enables a workaround that fixes a source of
973 spurious interrupts. This is recommended when threaded
974 interrupt handling is used on systems where the generation of
975 superfluous "boot interrupts" cannot be disabled.
977 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
978 entry in the chipset's IO-APIC is masked (as, e.g. the RT
979 kernel does during interrupt handling). On chipsets where this
980 boot IRQ generation cannot be disabled, this workaround keeps
981 the original IRQ line masked so that only the equivalent "boot
982 IRQ" is delivered to the CPUs. The workaround also tells the
983 kernel to set up the IRQ handler on the boot IRQ line. In this
984 way only one interrupt is delivered to the kernel. Otherwise
985 the spurious second interrupt may cause the kernel to bring
986 down (vital) interrupt lines.
988 Only affects "broken" chipsets. Interrupt sharing may be
989 increased on these systems.
992 bool "Machine Check / overheating reporting"
993 select GENERIC_ALLOCATOR
996 Machine Check support allows the processor to notify the
997 kernel if it detects a problem (e.g. overheating, data corruption).
998 The action the kernel takes depends on the severity of the problem,
999 ranging from warning messages to halting the machine.
1001 config X86_MCE_INTEL
1003 prompt "Intel MCE features"
1004 depends on X86_MCE && X86_LOCAL_APIC
1006 Additional support for intel specific MCE features such as
1007 the thermal monitor.
1011 prompt "AMD MCE features"
1012 depends on X86_MCE && X86_LOCAL_APIC
1014 Additional support for AMD specific MCE features such as
1015 the DRAM Error Threshold.
1017 config X86_ANCIENT_MCE
1018 bool "Support for old Pentium 5 / WinChip machine checks"
1019 depends on X86_32 && X86_MCE
1021 Include support for machine check handling on old Pentium 5 or WinChip
1022 systems. These typically need to be enabled explicitly on the command
1025 config X86_MCE_THRESHOLD
1026 depends on X86_MCE_AMD || X86_MCE_INTEL
1029 config X86_MCE_INJECT
1031 tristate "Machine check injector support"
1033 Provide support for injecting machine checks for testing purposes.
1034 If you don't know what a machine check is and you don't do kernel
1035 QA it is safe to say n.
1037 config X86_THERMAL_VECTOR
1039 depends on X86_MCE_INTEL
1041 config X86_LEGACY_VM86
1042 bool "Legacy VM86 support"
1046 This option allows user programs to put the CPU into V8086
1047 mode, which is an 80286-era approximation of 16-bit real mode.
1049 Some very old versions of X and/or vbetool require this option
1050 for user mode setting. Similarly, DOSEMU will use it if
1051 available to accelerate real mode DOS programs. However, any
1052 recent version of DOSEMU, X, or vbetool should be fully
1053 functional even without kernel VM86 support, as they will all
1054 fall back to software emulation. Nevertheless, if you are using
1055 a 16-bit DOS program where 16-bit performance matters, vm86
1056 mode might be faster than emulation and you might want to
1059 Note that any app that works on a 64-bit kernel is unlikely to
1060 need this option, as 64-bit kernels don't, and can't, support
1061 V8086 mode. This option is also unrelated to 16-bit protected
1062 mode and is not needed to run most 16-bit programs under Wine.
1064 Enabling this option increases the complexity of the kernel
1065 and slows down exception handling a tiny bit.
1067 If unsure, say N here.
1071 default X86_LEGACY_VM86
1074 bool "Enable support for 16-bit segments" if EXPERT
1076 depends on MODIFY_LDT_SYSCALL
1078 This option is required by programs like Wine to run 16-bit
1079 protected mode legacy code on x86 processors. Disabling
1080 this option saves about 300 bytes on i386, or around 6K text
1081 plus 16K runtime memory on x86-64,
1085 depends on X86_16BIT && X86_32
1089 depends on X86_16BIT && X86_64
1091 config X86_VSYSCALL_EMULATION
1092 bool "Enable vsyscall emulation" if EXPERT
1096 This enables emulation of the legacy vsyscall page. Disabling
1097 it is roughly equivalent to booting with vsyscall=none, except
1098 that it will also disable the helpful warning if a program
1099 tries to use a vsyscall. With this option set to N, offending
1100 programs will just segfault, citing addresses of the form
1103 This option is required by many programs built before 2013, and
1104 care should be used even with newer programs if set to N.
1106 Disabling this option saves about 7K of kernel size and
1107 possibly 4K of additional runtime pagetable memory.
1110 tristate "Toshiba Laptop support"
1113 This adds a driver to safely access the System Management Mode of
1114 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1115 not work on models with a Phoenix BIOS. The System Management Mode
1116 is used to set the BIOS and power saving options on Toshiba portables.
1118 For information on utilities to make use of this driver see the
1119 Toshiba Linux utilities web site at:
1120 <http://www.buzzard.org.uk/toshiba/>.
1122 Say Y if you intend to run this kernel on a Toshiba portable.
1126 tristate "Dell i8k legacy laptop support"
1128 select SENSORS_DELL_SMM
1130 This option enables legacy /proc/i8k userspace interface in hwmon
1131 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1132 temperature and allows controlling fan speeds of Dell laptops via
1133 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1134 it reports also power and hotkey status. For fan speed control is
1135 needed userspace package i8kutils.
1137 Say Y if you intend to run this kernel on old Dell laptops or want to
1138 use userspace package i8kutils.
1141 config X86_REBOOTFIXUPS
1142 bool "Enable X86 board specific fixups for reboot"
1145 This enables chipset and/or board specific fixups to be done
1146 in order to get reboot to work correctly. This is only needed on
1147 some combinations of hardware and BIOS. The symptom, for which
1148 this config is intended, is when reboot ends with a stalled/hung
1151 Currently, the only fixup is for the Geode machines using
1152 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1154 Say Y if you want to enable the fixup. Currently, it's safe to
1155 enable this option even if you don't need it.
1159 bool "CPU microcode loading support"
1161 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1162 depends on BLK_DEV_INITRD
1166 If you say Y here, you will be able to update the microcode on
1167 certain Intel and AMD processors. The Intel support is for the
1168 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1169 Xeon etc. The AMD support is for families 0x10 and later. You will
1170 obviously need the actual microcode binary data itself which is not
1171 shipped with the Linux kernel.
1173 This option selects the general module only, you need to select
1174 at least one vendor specific module as well.
1176 To compile this driver as a module, choose M here: the module
1177 will be called microcode.
1179 config MICROCODE_INTEL
1180 bool "Intel microcode loading support"
1181 depends on MICROCODE
1185 This options enables microcode patch loading support for Intel
1188 For the current Intel microcode data package go to
1189 <https://downloadcenter.intel.com> and search for
1190 'Linux Processor Microcode Data File'.
1192 config MICROCODE_AMD
1193 bool "AMD microcode loading support"
1194 depends on MICROCODE
1197 If you select this option, microcode patch loading support for AMD
1198 processors will be enabled.
1200 config MICROCODE_OLD_INTERFACE
1202 depends on MICROCODE
1205 tristate "/dev/cpu/*/msr - Model-specific register support"
1207 This device gives privileged processes access to the x86
1208 Model-Specific Registers (MSRs). It is a character device with
1209 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1210 MSR accesses are directed to a specific CPU on multi-processor
1214 tristate "/dev/cpu/*/cpuid - CPU information support"
1216 This device gives processes access to the x86 CPUID instruction to
1217 be executed on a specific processor. It is a character device
1218 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1222 prompt "High Memory Support"
1229 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1230 However, the address space of 32-bit x86 processors is only 4
1231 Gigabytes large. That means that, if you have a large amount of
1232 physical memory, not all of it can be "permanently mapped" by the
1233 kernel. The physical memory that's not permanently mapped is called
1236 If you are compiling a kernel which will never run on a machine with
1237 more than 1 Gigabyte total physical RAM, answer "off" here (default
1238 choice and suitable for most users). This will result in a "3GB/1GB"
1239 split: 3GB are mapped so that each process sees a 3GB virtual memory
1240 space and the remaining part of the 4GB virtual memory space is used
1241 by the kernel to permanently map as much physical memory as
1244 If the machine has between 1 and 4 Gigabytes physical RAM, then
1247 If more than 4 Gigabytes is used then answer "64GB" here. This
1248 selection turns Intel PAE (Physical Address Extension) mode on.
1249 PAE implements 3-level paging on IA32 processors. PAE is fully
1250 supported by Linux, PAE mode is implemented on all recent Intel
1251 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1252 then the kernel will not boot on CPUs that don't support PAE!
1254 The actual amount of total physical memory will either be
1255 auto detected or can be forced by using a kernel command line option
1256 such as "mem=256M". (Try "man bootparam" or see the documentation of
1257 your boot loader (lilo or loadlin) about how to pass options to the
1258 kernel at boot time.)
1260 If unsure, say "off".
1265 Select this if you have a 32-bit processor and between 1 and 4
1266 gigabytes of physical RAM.
1273 Select this if you have a 32-bit processor and more than 4
1274 gigabytes of physical RAM.
1279 prompt "Memory split" if EXPERT
1283 Select the desired split between kernel and user memory.
1285 If the address range available to the kernel is less than the
1286 physical memory installed, the remaining memory will be available
1287 as "high memory". Accessing high memory is a little more costly
1288 than low memory, as it needs to be mapped into the kernel first.
1289 Note that increasing the kernel address space limits the range
1290 available to user programs, making the address space there
1291 tighter. Selecting anything other than the default 3G/1G split
1292 will also likely make your kernel incompatible with binary-only
1295 If you are not absolutely sure what you are doing, leave this
1299 bool "3G/1G user/kernel split"
1300 config VMSPLIT_3G_OPT
1302 bool "3G/1G user/kernel split (for full 1G low memory)"
1304 bool "2G/2G user/kernel split"
1305 config VMSPLIT_2G_OPT
1307 bool "2G/2G user/kernel split (for full 2G low memory)"
1309 bool "1G/3G user/kernel split"
1314 default 0xB0000000 if VMSPLIT_3G_OPT
1315 default 0x80000000 if VMSPLIT_2G
1316 default 0x78000000 if VMSPLIT_2G_OPT
1317 default 0x40000000 if VMSPLIT_1G
1323 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1326 bool "PAE (Physical Address Extension) Support"
1327 depends on X86_32 && !HIGHMEM4G
1330 PAE is required for NX support, and furthermore enables
1331 larger swapspace support for non-overcommit purposes. It
1332 has the cost of more pagetable lookup overhead, and also
1333 consumes more pagetable space per process.
1335 config ARCH_PHYS_ADDR_T_64BIT
1337 depends on X86_64 || X86_PAE
1339 config ARCH_DMA_ADDR_T_64BIT
1341 depends on X86_64 || HIGHMEM64G
1343 config X86_DIRECT_GBPAGES
1345 depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1347 Certain kernel features effectively disable kernel
1348 linear 1 GB mappings (even if the CPU otherwise
1349 supports them), so don't confuse the user by printing
1350 that we have them enabled.
1352 # Common NUMA Features
1354 bool "Numa Memory Allocation and Scheduler Support"
1356 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1357 default y if X86_BIGSMP
1359 Enable NUMA (Non Uniform Memory Access) support.
1361 The kernel will try to allocate memory used by a CPU on the
1362 local memory controller of the CPU and add some more
1363 NUMA awareness to the kernel.
1365 For 64-bit this is recommended if the system is Intel Core i7
1366 (or later), AMD Opteron, or EM64T NUMA.
1368 For 32-bit this is only needed if you boot a 32-bit
1369 kernel on a 64-bit NUMA platform.
1371 Otherwise, you should say N.
1375 prompt "Old style AMD Opteron NUMA detection"
1376 depends on X86_64 && NUMA && PCI
1378 Enable AMD NUMA node topology detection. You should say Y here if
1379 you have a multi processor AMD system. This uses an old method to
1380 read the NUMA configuration directly from the builtin Northbridge
1381 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1382 which also takes priority if both are compiled in.
1384 config X86_64_ACPI_NUMA
1386 prompt "ACPI NUMA detection"
1387 depends on X86_64 && NUMA && ACPI && PCI
1390 Enable ACPI SRAT based node topology detection.
1392 # Some NUMA nodes have memory ranges that span
1393 # other nodes. Even though a pfn is valid and
1394 # between a node's start and end pfns, it may not
1395 # reside on that node. See memmap_init_zone()
1397 config NODES_SPAN_OTHER_NODES
1399 depends on X86_64_ACPI_NUMA
1402 bool "NUMA emulation"
1405 Enable NUMA emulation. A flat machine will be split
1406 into virtual nodes when booted with "numa=fake=N", where N is the
1407 number of nodes. This is only useful for debugging.
1410 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1412 default "10" if MAXSMP
1413 default "6" if X86_64
1415 depends on NEED_MULTIPLE_NODES
1417 Specify the maximum number of NUMA Nodes available on the target
1418 system. Increases memory reserved to accommodate various tables.
1420 config ARCH_HAVE_MEMORY_PRESENT
1422 depends on X86_32 && DISCONTIGMEM
1424 config NEED_NODE_MEMMAP_SIZE
1426 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1428 config ARCH_FLATMEM_ENABLE
1430 depends on X86_32 && !NUMA
1432 config ARCH_DISCONTIGMEM_ENABLE
1434 depends on NUMA && X86_32
1436 config ARCH_DISCONTIGMEM_DEFAULT
1438 depends on NUMA && X86_32
1440 config ARCH_SPARSEMEM_ENABLE
1442 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1443 select SPARSEMEM_STATIC if X86_32
1444 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1446 config ARCH_SPARSEMEM_DEFAULT
1450 config ARCH_SELECT_MEMORY_MODEL
1452 depends on ARCH_SPARSEMEM_ENABLE
1454 config ARCH_MEMORY_PROBE
1455 bool "Enable sysfs memory/probe interface"
1456 depends on X86_64 && MEMORY_HOTPLUG
1458 This option enables a sysfs memory/probe interface for testing.
1459 See Documentation/memory-hotplug.txt for more information.
1460 If you are unsure how to answer this question, answer N.
1462 config ARCH_PROC_KCORE_TEXT
1464 depends on X86_64 && PROC_KCORE
1466 config ILLEGAL_POINTER_VALUE
1469 default 0xdead000000000000 if X86_64
1473 config X86_PMEM_LEGACY_DEVICE
1476 config X86_PMEM_LEGACY
1477 tristate "Support non-standard NVDIMMs and ADR protected memory"
1478 depends on PHYS_ADDR_T_64BIT
1480 select X86_PMEM_LEGACY_DEVICE
1483 Treat memory marked using the non-standard e820 type of 12 as used
1484 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1485 The kernel will offer these regions to the 'pmem' driver so
1486 they can be used for persistent storage.
1491 bool "Allocate 3rd-level pagetables from highmem"
1494 The VM uses one page table entry for each page of physical memory.
1495 For systems with a lot of RAM, this can be wasteful of precious
1496 low memory. Setting this option will put user-space page table
1497 entries in high memory.
1499 config X86_CHECK_BIOS_CORRUPTION
1500 bool "Check for low memory corruption"
1502 Periodically check for memory corruption in low memory, which
1503 is suspected to be caused by BIOS. Even when enabled in the
1504 configuration, it is disabled at runtime. Enable it by
1505 setting "memory_corruption_check=1" on the kernel command
1506 line. By default it scans the low 64k of memory every 60
1507 seconds; see the memory_corruption_check_size and
1508 memory_corruption_check_period parameters in
1509 Documentation/kernel-parameters.txt to adjust this.
1511 When enabled with the default parameters, this option has
1512 almost no overhead, as it reserves a relatively small amount
1513 of memory and scans it infrequently. It both detects corruption
1514 and prevents it from affecting the running system.
1516 It is, however, intended as a diagnostic tool; if repeatable
1517 BIOS-originated corruption always affects the same memory,
1518 you can use memmap= to prevent the kernel from using that
1521 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1522 bool "Set the default setting of memory_corruption_check"
1523 depends on X86_CHECK_BIOS_CORRUPTION
1526 Set whether the default state of memory_corruption_check is
1529 config X86_RESERVE_LOW
1530 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1534 Specify the amount of low memory to reserve for the BIOS.
1536 The first page contains BIOS data structures that the kernel
1537 must not use, so that page must always be reserved.
1539 By default we reserve the first 64K of physical RAM, as a
1540 number of BIOSes are known to corrupt that memory range
1541 during events such as suspend/resume or monitor cable
1542 insertion, so it must not be used by the kernel.
1544 You can set this to 4 if you are absolutely sure that you
1545 trust the BIOS to get all its memory reservations and usages
1546 right. If you know your BIOS have problems beyond the
1547 default 64K area, you can set this to 640 to avoid using the
1548 entire low memory range.
1550 If you have doubts about the BIOS (e.g. suspend/resume does
1551 not work or there's kernel crashes after certain hardware
1552 hotplug events) then you might want to enable
1553 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1554 typical corruption patterns.
1556 Leave this to the default value of 64 if you are unsure.
1558 config MATH_EMULATION
1560 depends on MODIFY_LDT_SYSCALL
1561 prompt "Math emulation" if X86_32
1563 Linux can emulate a math coprocessor (used for floating point
1564 operations) if you don't have one. 486DX and Pentium processors have
1565 a math coprocessor built in, 486SX and 386 do not, unless you added
1566 a 487DX or 387, respectively. (The messages during boot time can
1567 give you some hints here ["man dmesg"].) Everyone needs either a
1568 coprocessor or this emulation.
1570 If you don't have a math coprocessor, you need to say Y here; if you
1571 say Y here even though you have a coprocessor, the coprocessor will
1572 be used nevertheless. (This behavior can be changed with the kernel
1573 command line option "no387", which comes handy if your coprocessor
1574 is broken. Try "man bootparam" or see the documentation of your boot
1575 loader (lilo or loadlin) about how to pass options to the kernel at
1576 boot time.) This means that it is a good idea to say Y here if you
1577 intend to use this kernel on different machines.
1579 More information about the internals of the Linux math coprocessor
1580 emulation can be found in <file:arch/x86/math-emu/README>.
1582 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1583 kernel, it won't hurt.
1587 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1589 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1590 the Memory Type Range Registers (MTRRs) may be used to control
1591 processor access to memory ranges. This is most useful if you have
1592 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1593 allows bus write transfers to be combined into a larger transfer
1594 before bursting over the PCI/AGP bus. This can increase performance
1595 of image write operations 2.5 times or more. Saying Y here creates a
1596 /proc/mtrr file which may be used to manipulate your processor's
1597 MTRRs. Typically the X server should use this.
1599 This code has a reasonably generic interface so that similar
1600 control registers on other processors can be easily supported
1603 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1604 Registers (ARRs) which provide a similar functionality to MTRRs. For
1605 these, the ARRs are used to emulate the MTRRs.
1606 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1607 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1608 write-combining. All of these processors are supported by this code
1609 and it makes sense to say Y here if you have one of them.
1611 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1612 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1613 can lead to all sorts of problems, so it's good to say Y here.
1615 You can safely say Y even if your machine doesn't have MTRRs, you'll
1616 just add about 9 KB to your kernel.
1618 See <file:Documentation/x86/mtrr.txt> for more information.
1620 config MTRR_SANITIZER
1622 prompt "MTRR cleanup support"
1625 Convert MTRR layout from continuous to discrete, so X drivers can
1626 add writeback entries.
1628 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1629 The largest mtrr entry size for a continuous block can be set with
1634 config MTRR_SANITIZER_ENABLE_DEFAULT
1635 int "MTRR cleanup enable value (0-1)"
1638 depends on MTRR_SANITIZER
1640 Enable mtrr cleanup default value
1642 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1643 int "MTRR cleanup spare reg num (0-7)"
1646 depends on MTRR_SANITIZER
1648 mtrr cleanup spare entries default, it can be changed via
1649 mtrr_spare_reg_nr=N on the kernel command line.
1653 prompt "x86 PAT support" if EXPERT
1656 Use PAT attributes to setup page level cache control.
1658 PATs are the modern equivalents of MTRRs and are much more
1659 flexible than MTRRs.
1661 Say N here if you see bootup problems (boot crash, boot hang,
1662 spontaneous reboots) or a non-working video driver.
1666 config ARCH_USES_PG_UNCACHED
1672 prompt "x86 architectural random number generator" if EXPERT
1674 Enable the x86 architectural RDRAND instruction
1675 (Intel Bull Mountain technology) to generate random numbers.
1676 If supported, this is a high bandwidth, cryptographically
1677 secure hardware random number generator.
1681 prompt "Supervisor Mode Access Prevention" if EXPERT
1683 Supervisor Mode Access Prevention (SMAP) is a security
1684 feature in newer Intel processors. There is a small
1685 performance cost if this enabled and turned on; there is
1686 also a small increase in the kernel size if this is enabled.
1690 config X86_INTEL_MPX
1691 prompt "Intel MPX (Memory Protection Extensions)"
1693 depends on CPU_SUP_INTEL
1695 MPX provides hardware features that can be used in
1696 conjunction with compiler-instrumented code to check
1697 memory references. It is designed to detect buffer
1698 overflow or underflow bugs.
1700 This option enables running applications which are
1701 instrumented or otherwise use MPX. It does not use MPX
1702 itself inside the kernel or to protect the kernel
1703 against bad memory references.
1705 Enabling this option will make the kernel larger:
1706 ~8k of kernel text and 36 bytes of data on a 64-bit
1707 defconfig. It adds a long to the 'mm_struct' which
1708 will increase the kernel memory overhead of each
1709 process and adds some branches to paths used during
1710 exec() and munmap().
1712 For details, see Documentation/x86/intel_mpx.txt
1717 bool "EFI runtime service support"
1720 select EFI_RUNTIME_WRAPPERS
1722 This enables the kernel to use EFI runtime services that are
1723 available (such as the EFI variable services).
1725 This option is only useful on systems that have EFI firmware.
1726 In addition, you should use the latest ELILO loader available
1727 at <http://elilo.sourceforge.net> in order to take advantage
1728 of EFI runtime services. However, even with this option, the
1729 resultant kernel should continue to boot on existing non-EFI
1733 bool "EFI stub support"
1734 depends on EFI && !X86_USE_3DNOW
1737 This kernel feature allows a bzImage to be loaded directly
1738 by EFI firmware without the use of a bootloader.
1740 See Documentation/efi-stub.txt for more information.
1743 bool "EFI mixed-mode support"
1744 depends on EFI_STUB && X86_64
1746 Enabling this feature allows a 64-bit kernel to be booted
1747 on a 32-bit firmware, provided that your CPU supports 64-bit
1750 Note that it is not possible to boot a mixed-mode enabled
1751 kernel via the EFI boot stub - a bootloader that supports
1752 the EFI handover protocol must be used.
1758 prompt "Enable seccomp to safely compute untrusted bytecode"
1760 This kernel feature is useful for number crunching applications
1761 that may need to compute untrusted bytecode during their
1762 execution. By using pipes or other transports made available to
1763 the process as file descriptors supporting the read/write
1764 syscalls, it's possible to isolate those applications in
1765 their own address space using seccomp. Once seccomp is
1766 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1767 and the task is only allowed to execute a few safe syscalls
1768 defined by each seccomp mode.
1770 If unsure, say Y. Only embedded should say N here.
1772 source kernel/Kconfig.hz
1775 bool "kexec system call"
1778 kexec is a system call that implements the ability to shutdown your
1779 current kernel, and to start another kernel. It is like a reboot
1780 but it is independent of the system firmware. And like a reboot
1781 you can start any kernel with it, not just Linux.
1783 The name comes from the similarity to the exec system call.
1785 It is an ongoing process to be certain the hardware in a machine
1786 is properly shutdown, so do not be surprised if this code does not
1787 initially work for you. As of this writing the exact hardware
1788 interface is strongly in flux, so no good recommendation can be
1792 bool "kexec file based system call"
1797 depends on CRYPTO_SHA256=y
1799 This is new version of kexec system call. This system call is
1800 file based and takes file descriptors as system call argument
1801 for kernel and initramfs as opposed to list of segments as
1802 accepted by previous system call.
1804 config KEXEC_VERIFY_SIG
1805 bool "Verify kernel signature during kexec_file_load() syscall"
1806 depends on KEXEC_FILE
1808 This option makes kernel signature verification mandatory for
1809 the kexec_file_load() syscall.
1811 In addition to that option, you need to enable signature
1812 verification for the corresponding kernel image type being
1813 loaded in order for this to work.
1815 config KEXEC_BZIMAGE_VERIFY_SIG
1816 bool "Enable bzImage signature verification support"
1817 depends on KEXEC_VERIFY_SIG
1818 depends on SIGNED_PE_FILE_VERIFICATION
1819 select SYSTEM_TRUSTED_KEYRING
1821 Enable bzImage signature verification support.
1824 bool "kernel crash dumps"
1825 depends on X86_64 || (X86_32 && HIGHMEM)
1827 Generate crash dump after being started by kexec.
1828 This should be normally only set in special crash dump kernels
1829 which are loaded in the main kernel with kexec-tools into
1830 a specially reserved region and then later executed after
1831 a crash by kdump/kexec. The crash dump kernel must be compiled
1832 to a memory address not used by the main kernel or BIOS using
1833 PHYSICAL_START, or it must be built as a relocatable image
1834 (CONFIG_RELOCATABLE=y).
1835 For more details see Documentation/kdump/kdump.txt
1839 depends on KEXEC && HIBERNATION
1841 Jump between original kernel and kexeced kernel and invoke
1842 code in physical address mode via KEXEC
1844 config PHYSICAL_START
1845 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1848 This gives the physical address where the kernel is loaded.
1850 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1851 bzImage will decompress itself to above physical address and
1852 run from there. Otherwise, bzImage will run from the address where
1853 it has been loaded by the boot loader and will ignore above physical
1856 In normal kdump cases one does not have to set/change this option
1857 as now bzImage can be compiled as a completely relocatable image
1858 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1859 address. This option is mainly useful for the folks who don't want
1860 to use a bzImage for capturing the crash dump and want to use a
1861 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1862 to be specifically compiled to run from a specific memory area
1863 (normally a reserved region) and this option comes handy.
1865 So if you are using bzImage for capturing the crash dump,
1866 leave the value here unchanged to 0x1000000 and set
1867 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1868 for capturing the crash dump change this value to start of
1869 the reserved region. In other words, it can be set based on
1870 the "X" value as specified in the "crashkernel=YM@XM"
1871 command line boot parameter passed to the panic-ed
1872 kernel. Please take a look at Documentation/kdump/kdump.txt
1873 for more details about crash dumps.
1875 Usage of bzImage for capturing the crash dump is recommended as
1876 one does not have to build two kernels. Same kernel can be used
1877 as production kernel and capture kernel. Above option should have
1878 gone away after relocatable bzImage support is introduced. But it
1879 is present because there are users out there who continue to use
1880 vmlinux for dump capture. This option should go away down the
1883 Don't change this unless you know what you are doing.
1886 bool "Build a relocatable kernel"
1889 This builds a kernel image that retains relocation information
1890 so it can be loaded someplace besides the default 1MB.
1891 The relocations tend to make the kernel binary about 10% larger,
1892 but are discarded at runtime.
1894 One use is for the kexec on panic case where the recovery kernel
1895 must live at a different physical address than the primary
1898 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1899 it has been loaded at and the compile time physical address
1900 (CONFIG_PHYSICAL_START) is used as the minimum location.
1902 config RANDOMIZE_BASE
1903 bool "Randomize the address of the kernel image"
1904 depends on RELOCATABLE
1907 Randomizes the physical and virtual address at which the
1908 kernel image is decompressed, as a security feature that
1909 deters exploit attempts relying on knowledge of the location
1910 of kernel internals.
1912 Entropy is generated using the RDRAND instruction if it is
1913 supported. If RDTSC is supported, it is used as well. If
1914 neither RDRAND nor RDTSC are supported, then randomness is
1915 read from the i8254 timer.
1917 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1918 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1919 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1920 minimum of 2MiB, only 10 bits of entropy is theoretically
1921 possible. At best, due to page table layouts, 64-bit can use
1922 9 bits of entropy and 32-bit uses 8 bits.
1926 config RANDOMIZE_BASE_MAX_OFFSET
1927 hex "Maximum kASLR offset allowed" if EXPERT
1928 depends on RANDOMIZE_BASE
1929 range 0x0 0x20000000 if X86_32
1930 default "0x20000000" if X86_32
1931 range 0x0 0x40000000 if X86_64
1932 default "0x40000000" if X86_64
1934 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1935 memory is used to determine the maximal offset in bytes that will
1936 be applied to the kernel when kernel Address Space Layout
1937 Randomization (kASLR) is active. This must be a multiple of
1940 On 32-bit this is limited to 512MiB by page table layouts. The
1943 On 64-bit this is limited by how the kernel fixmap page table is
1944 positioned, so this cannot be larger than 1GiB currently. Without
1945 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1946 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1947 modules area will shrink to compensate, up to the current maximum
1948 1GiB to 1GiB split. The default is 1GiB.
1950 If unsure, leave at the default value.
1952 # Relocation on x86 needs some additional build support
1953 config X86_NEED_RELOCS
1955 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1957 config PHYSICAL_ALIGN
1958 hex "Alignment value to which kernel should be aligned"
1960 range 0x2000 0x1000000 if X86_32
1961 range 0x200000 0x1000000 if X86_64
1963 This value puts the alignment restrictions on physical address
1964 where kernel is loaded and run from. Kernel is compiled for an
1965 address which meets above alignment restriction.
1967 If bootloader loads the kernel at a non-aligned address and
1968 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1969 address aligned to above value and run from there.
1971 If bootloader loads the kernel at a non-aligned address and
1972 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1973 load address and decompress itself to the address it has been
1974 compiled for and run from there. The address for which kernel is
1975 compiled already meets above alignment restrictions. Hence the
1976 end result is that kernel runs from a physical address meeting
1977 above alignment restrictions.
1979 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1980 this value must be a multiple of 0x200000.
1982 Don't change this unless you know what you are doing.
1985 bool "Support for hot-pluggable CPUs"
1988 Say Y here to allow turning CPUs off and on. CPUs can be
1989 controlled through /sys/devices/system/cpu.
1990 ( Note: power management support will enable this option
1991 automatically on SMP systems. )
1992 Say N if you want to disable CPU hotplug.
1994 config BOOTPARAM_HOTPLUG_CPU0
1995 bool "Set default setting of cpu0_hotpluggable"
1997 depends on HOTPLUG_CPU
1999 Set whether default state of cpu0_hotpluggable is on or off.
2001 Say Y here to enable CPU0 hotplug by default. If this switch
2002 is turned on, there is no need to give cpu0_hotplug kernel
2003 parameter and the CPU0 hotplug feature is enabled by default.
2005 Please note: there are two known CPU0 dependencies if you want
2006 to enable the CPU0 hotplug feature either by this switch or by
2007 cpu0_hotplug kernel parameter.
2009 First, resume from hibernate or suspend always starts from CPU0.
2010 So hibernate and suspend are prevented if CPU0 is offline.
2012 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2013 offline if any interrupt can not migrate out of CPU0. There may
2014 be other CPU0 dependencies.
2016 Please make sure the dependencies are under your control before
2017 you enable this feature.
2019 Say N if you don't want to enable CPU0 hotplug feature by default.
2020 You still can enable the CPU0 hotplug feature at boot by kernel
2021 parameter cpu0_hotplug.
2023 config DEBUG_HOTPLUG_CPU0
2025 prompt "Debug CPU0 hotplug"
2026 depends on HOTPLUG_CPU
2028 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2029 soon as possible and boots up userspace with CPU0 offlined. User
2030 can online CPU0 back after boot time.
2032 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2033 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2034 compilation or giving cpu0_hotplug kernel parameter at boot.
2040 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2041 depends on X86_32 || IA32_EMULATION
2043 Certain buggy versions of glibc will crash if they are
2044 presented with a 32-bit vDSO that is not mapped at the address
2045 indicated in its segment table.
2047 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2048 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2049 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2050 the only released version with the bug, but OpenSUSE 9
2051 contains a buggy "glibc 2.3.2".
2053 The symptom of the bug is that everything crashes on startup, saying:
2054 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2056 Saying Y here changes the default value of the vdso32 boot
2057 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2058 This works around the glibc bug but hurts performance.
2060 If unsure, say N: if you are compiling your own kernel, you
2061 are unlikely to be using a buggy version of glibc.
2064 prompt "vsyscall table for legacy applications"
2066 default LEGACY_VSYSCALL_EMULATE
2068 Legacy user code that does not know how to find the vDSO expects
2069 to be able to issue three syscalls by calling fixed addresses in
2070 kernel space. Since this location is not randomized with ASLR,
2071 it can be used to assist security vulnerability exploitation.
2073 This setting can be changed at boot time via the kernel command
2074 line parameter vsyscall=[native|emulate|none].
2076 On a system with recent enough glibc (2.14 or newer) and no
2077 static binaries, you can say None without a performance penalty
2078 to improve security.
2080 If unsure, select "Emulate".
2082 config LEGACY_VSYSCALL_NATIVE
2085 Actual executable code is located in the fixed vsyscall
2086 address mapping, implementing time() efficiently. Since
2087 this makes the mapping executable, it can be used during
2088 security vulnerability exploitation (traditionally as
2089 ROP gadgets). This configuration is not recommended.
2091 config LEGACY_VSYSCALL_EMULATE
2094 The kernel traps and emulates calls into the fixed
2095 vsyscall address mapping. This makes the mapping
2096 non-executable, but it still contains known contents,
2097 which could be used in certain rare security vulnerability
2098 exploits. This configuration is recommended when userspace
2099 still uses the vsyscall area.
2101 config LEGACY_VSYSCALL_NONE
2104 There will be no vsyscall mapping at all. This will
2105 eliminate any risk of ASLR bypass due to the vsyscall
2106 fixed address mapping. Attempts to use the vsyscalls
2107 will be reported to dmesg, so that either old or
2108 malicious userspace programs can be identified.
2113 bool "Built-in kernel command line"
2115 Allow for specifying boot arguments to the kernel at
2116 build time. On some systems (e.g. embedded ones), it is
2117 necessary or convenient to provide some or all of the
2118 kernel boot arguments with the kernel itself (that is,
2119 to not rely on the boot loader to provide them.)
2121 To compile command line arguments into the kernel,
2122 set this option to 'Y', then fill in the
2123 boot arguments in CONFIG_CMDLINE.
2125 Systems with fully functional boot loaders (i.e. non-embedded)
2126 should leave this option set to 'N'.
2129 string "Built-in kernel command string"
2130 depends on CMDLINE_BOOL
2133 Enter arguments here that should be compiled into the kernel
2134 image and used at boot time. If the boot loader provides a
2135 command line at boot time, it is appended to this string to
2136 form the full kernel command line, when the system boots.
2138 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2139 change this behavior.
2141 In most cases, the command line (whether built-in or provided
2142 by the boot loader) should specify the device for the root
2145 config CMDLINE_OVERRIDE
2146 bool "Built-in command line overrides boot loader arguments"
2147 depends on CMDLINE_BOOL
2149 Set this option to 'Y' to have the kernel ignore the boot loader
2150 command line, and use ONLY the built-in command line.
2152 This is used to work around broken boot loaders. This should
2153 be set to 'N' under normal conditions.
2155 config MODIFY_LDT_SYSCALL
2156 bool "Enable the LDT (local descriptor table)" if EXPERT
2159 Linux can allow user programs to install a per-process x86
2160 Local Descriptor Table (LDT) using the modify_ldt(2) system
2161 call. This is required to run 16-bit or segmented code such as
2162 DOSEMU or some Wine programs. It is also used by some very old
2163 threading libraries.
2165 Enabling this feature adds a small amount of overhead to
2166 context switches and increases the low-level kernel attack
2167 surface. Disabling it removes the modify_ldt(2) system call.
2169 Saying 'N' here may make sense for embedded or server kernels.
2171 source "kernel/livepatch/Kconfig"
2175 config ARCH_ENABLE_MEMORY_HOTPLUG
2177 depends on X86_64 || (X86_32 && HIGHMEM)
2179 config ARCH_ENABLE_MEMORY_HOTREMOVE
2181 depends on MEMORY_HOTPLUG
2183 config USE_PERCPU_NUMA_NODE_ID
2187 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2189 depends on X86_64 || X86_PAE
2191 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2193 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2195 menu "Power management and ACPI options"
2197 config ARCH_HIBERNATION_HEADER
2199 depends on X86_64 && HIBERNATION
2201 source "kernel/power/Kconfig"
2203 source "drivers/acpi/Kconfig"
2205 source "drivers/sfi/Kconfig"
2212 tristate "APM (Advanced Power Management) BIOS support"
2213 depends on X86_32 && PM_SLEEP
2215 APM is a BIOS specification for saving power using several different
2216 techniques. This is mostly useful for battery powered laptops with
2217 APM compliant BIOSes. If you say Y here, the system time will be
2218 reset after a RESUME operation, the /proc/apm device will provide
2219 battery status information, and user-space programs will receive
2220 notification of APM "events" (e.g. battery status change).
2222 If you select "Y" here, you can disable actual use of the APM
2223 BIOS by passing the "apm=off" option to the kernel at boot time.
2225 Note that the APM support is almost completely disabled for
2226 machines with more than one CPU.
2228 In order to use APM, you will need supporting software. For location
2229 and more information, read <file:Documentation/power/apm-acpi.txt>
2230 and the Battery Powered Linux mini-HOWTO, available from
2231 <http://www.tldp.org/docs.html#howto>.
2233 This driver does not spin down disk drives (see the hdparm(8)
2234 manpage ("man 8 hdparm") for that), and it doesn't turn off
2235 VESA-compliant "green" monitors.
2237 This driver does not support the TI 4000M TravelMate and the ACER
2238 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2239 desktop machines also don't have compliant BIOSes, and this driver
2240 may cause those machines to panic during the boot phase.
2242 Generally, if you don't have a battery in your machine, there isn't
2243 much point in using this driver and you should say N. If you get
2244 random kernel OOPSes or reboots that don't seem to be related to
2245 anything, try disabling/enabling this option (or disabling/enabling
2248 Some other things you should try when experiencing seemingly random,
2251 1) make sure that you have enough swap space and that it is
2253 2) pass the "no-hlt" option to the kernel
2254 3) switch on floating point emulation in the kernel and pass
2255 the "no387" option to the kernel
2256 4) pass the "floppy=nodma" option to the kernel
2257 5) pass the "mem=4M" option to the kernel (thereby disabling
2258 all but the first 4 MB of RAM)
2259 6) make sure that the CPU is not over clocked.
2260 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2261 8) disable the cache from your BIOS settings
2262 9) install a fan for the video card or exchange video RAM
2263 10) install a better fan for the CPU
2264 11) exchange RAM chips
2265 12) exchange the motherboard.
2267 To compile this driver as a module, choose M here: the
2268 module will be called apm.
2272 config APM_IGNORE_USER_SUSPEND
2273 bool "Ignore USER SUSPEND"
2275 This option will ignore USER SUSPEND requests. On machines with a
2276 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2277 series notebooks, it is necessary to say Y because of a BIOS bug.
2279 config APM_DO_ENABLE
2280 bool "Enable PM at boot time"
2282 Enable APM features at boot time. From page 36 of the APM BIOS
2283 specification: "When disabled, the APM BIOS does not automatically
2284 power manage devices, enter the Standby State, enter the Suspend
2285 State, or take power saving steps in response to CPU Idle calls."
2286 This driver will make CPU Idle calls when Linux is idle (unless this
2287 feature is turned off -- see "Do CPU IDLE calls", below). This
2288 should always save battery power, but more complicated APM features
2289 will be dependent on your BIOS implementation. You may need to turn
2290 this option off if your computer hangs at boot time when using APM
2291 support, or if it beeps continuously instead of suspending. Turn
2292 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2293 T400CDT. This is off by default since most machines do fine without
2298 bool "Make CPU Idle calls when idle"
2300 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2301 On some machines, this can activate improved power savings, such as
2302 a slowed CPU clock rate, when the machine is idle. These idle calls
2303 are made after the idle loop has run for some length of time (e.g.,
2304 333 mS). On some machines, this will cause a hang at boot time or
2305 whenever the CPU becomes idle. (On machines with more than one CPU,
2306 this option does nothing.)
2308 config APM_DISPLAY_BLANK
2309 bool "Enable console blanking using APM"
2311 Enable console blanking using the APM. Some laptops can use this to
2312 turn off the LCD backlight when the screen blanker of the Linux
2313 virtual console blanks the screen. Note that this is only used by
2314 the virtual console screen blanker, and won't turn off the backlight
2315 when using the X Window system. This also doesn't have anything to
2316 do with your VESA-compliant power-saving monitor. Further, this
2317 option doesn't work for all laptops -- it might not turn off your
2318 backlight at all, or it might print a lot of errors to the console,
2319 especially if you are using gpm.
2321 config APM_ALLOW_INTS
2322 bool "Allow interrupts during APM BIOS calls"
2324 Normally we disable external interrupts while we are making calls to
2325 the APM BIOS as a measure to lessen the effects of a badly behaving
2326 BIOS implementation. The BIOS should reenable interrupts if it
2327 needs to. Unfortunately, some BIOSes do not -- especially those in
2328 many of the newer IBM Thinkpads. If you experience hangs when you
2329 suspend, try setting this to Y. Otherwise, say N.
2333 source "drivers/cpufreq/Kconfig"
2335 source "drivers/cpuidle/Kconfig"
2337 source "drivers/idle/Kconfig"
2342 menu "Bus options (PCI etc.)"
2348 Find out whether you have a PCI motherboard. PCI is the name of a
2349 bus system, i.e. the way the CPU talks to the other stuff inside
2350 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2351 VESA. If you have PCI, say Y, otherwise N.
2354 prompt "PCI access mode"
2355 depends on X86_32 && PCI
2358 On PCI systems, the BIOS can be used to detect the PCI devices and
2359 determine their configuration. However, some old PCI motherboards
2360 have BIOS bugs and may crash if this is done. Also, some embedded
2361 PCI-based systems don't have any BIOS at all. Linux can also try to
2362 detect the PCI hardware directly without using the BIOS.
2364 With this option, you can specify how Linux should detect the
2365 PCI devices. If you choose "BIOS", the BIOS will be used,
2366 if you choose "Direct", the BIOS won't be used, and if you
2367 choose "MMConfig", then PCI Express MMCONFIG will be used.
2368 If you choose "Any", the kernel will try MMCONFIG, then the
2369 direct access method and falls back to the BIOS if that doesn't
2370 work. If unsure, go with the default, which is "Any".
2375 config PCI_GOMMCONFIG
2392 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2394 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2397 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2401 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2405 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2409 depends on PCI && XEN
2417 bool "Support mmconfig PCI config space access"
2418 depends on X86_64 && PCI && ACPI
2420 config PCI_CNB20LE_QUIRK
2421 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2424 Read the PCI windows out of the CNB20LE host bridge. This allows
2425 PCI hotplug to work on systems with the CNB20LE chipset which do
2428 There's no public spec for this chipset, and this functionality
2429 is known to be incomplete.
2431 You should say N unless you know you need this.
2433 source "drivers/pci/pcie/Kconfig"
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"
2590 source "drivers/pci/hotplug/Kconfig"
2593 tristate "RapidIO support"
2597 If enabled this option will include drivers and the core
2598 infrastructure code to support RapidIO interconnect devices.
2600 source "drivers/rapidio/Kconfig"
2603 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2605 Firmwares often provide initial graphics framebuffers so the BIOS,
2606 bootloader or kernel can show basic video-output during boot for
2607 user-guidance and debugging. Historically, x86 used the VESA BIOS
2608 Extensions and EFI-framebuffers for this, which are mostly limited
2610 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2611 framebuffers so the new generic system-framebuffer drivers can be
2612 used on x86. If the framebuffer is not compatible with the generic
2613 modes, it is adverticed as fallback platform framebuffer so legacy
2614 drivers like efifb, vesafb and uvesafb can pick it up.
2615 If this option is not selected, all system framebuffers are always
2616 marked as fallback platform framebuffers as usual.
2618 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2619 not be able to pick up generic system framebuffers if this option
2620 is selected. You are highly encouraged to enable simplefb as
2621 replacement if you select this option. simplefb can correctly deal
2622 with generic system framebuffers. But you should still keep vesafb
2623 and others enabled as fallback if a system framebuffer is
2624 incompatible with simplefb.
2631 menu "Executable file formats / Emulations"
2633 source "fs/Kconfig.binfmt"
2635 config IA32_EMULATION
2636 bool "IA32 Emulation"
2639 select COMPAT_BINFMT_ELF
2640 select ARCH_WANT_OLD_COMPAT_IPC
2642 Include code to run legacy 32-bit programs under a
2643 64-bit kernel. You should likely turn this on, unless you're
2644 100% sure that you don't have any 32-bit programs left.
2647 tristate "IA32 a.out support"
2648 depends on IA32_EMULATION
2650 Support old a.out binaries in the 32bit emulation.
2653 bool "x32 ABI for 64-bit mode"
2656 Include code to run binaries for the x32 native 32-bit ABI
2657 for 64-bit processors. An x32 process gets access to the
2658 full 64-bit register file and wide data path while leaving
2659 pointers at 32 bits for smaller memory footprint.
2661 You will need a recent binutils (2.22 or later) with
2662 elf32_x86_64 support enabled to compile a kernel with this
2667 depends on IA32_EMULATION || X86_X32
2670 config COMPAT_FOR_U64_ALIGNMENT
2673 config SYSVIPC_COMPAT
2685 config HAVE_ATOMIC_IOMAP
2689 config X86_DEV_DMA_OPS
2691 depends on X86_64 || STA2X11
2693 config X86_DMA_REMAP
2703 tristate "Volume Management Device Driver"
2706 Adds support for the Intel Volume Management Device (VMD). VMD is a
2707 secondary PCI host bridge that allows PCI Express root ports,
2708 and devices attached to them, to be removed from the default
2709 PCI domain and placed within the VMD domain. This provides
2710 more bus resources than are otherwise possible with a
2711 single domain. If you know your system provides one of these and
2712 has devices attached to it, say Y; if you are not sure, say N.
2714 source "net/Kconfig"
2716 source "drivers/Kconfig"
2718 source "drivers/firmware/Kconfig"
2722 source "arch/x86/Kconfig.debug"
2724 source "security/Kconfig"
2726 source "crypto/Kconfig"
2728 source "arch/x86/kvm/Kconfig"
2730 source "lib/Kconfig"
git.samba.org / sfrench / cifs-2.6.git / blob