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_ELF_RANDOMIZE
28 select ARCH_HAS_FAST_MULTIPLIER
29 select ARCH_HAS_GCOV_PROFILE_ALL
30 select ARCH_HAS_PMEM_API
31 select ARCH_HAS_SG_CHAIN
32 select ARCH_HAVE_NMI_SAFE_CMPXCHG
33 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
34 select ARCH_MIGHT_HAVE_PC_PARPORT
35 select ARCH_MIGHT_HAVE_PC_SERIO
36 select ARCH_SUPPORTS_ATOMIC_RMW
37 select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
38 select ARCH_SUPPORTS_INT128 if X86_64
39 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
40 select ARCH_USE_BUILTIN_BSWAP
41 select ARCH_USE_CMPXCHG_LOCKREF if X86_64
42 select ARCH_USE_QUEUED_RWLOCKS
43 select ARCH_USE_QUEUED_SPINLOCKS
44 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if SMP
45 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
46 select ARCH_WANT_FRAME_POINTERS
47 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
48 select ARCH_WANT_OPTIONAL_GPIOLIB
49 select BUILDTIME_EXTABLE_SORT
51 select CLKSRC_I8253 if X86_32
52 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
53 select CLOCKSOURCE_WATCHDOG
54 select CLONE_BACKWARDS if X86_32
55 select COMPAT_OLD_SIGACTION if IA32_EMULATION
56 select DCACHE_WORD_ACCESS
57 select EDAC_ATOMIC_SCRUB
59 select GENERIC_CLOCKEVENTS
60 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
61 select GENERIC_CLOCKEVENTS_MIN_ADJUST
62 select GENERIC_CMOS_UPDATE
63 select GENERIC_CPU_AUTOPROBE
64 select GENERIC_EARLY_IOREMAP
65 select GENERIC_FIND_FIRST_BIT
67 select GENERIC_IRQ_PROBE
68 select GENERIC_IRQ_SHOW
69 select GENERIC_PENDING_IRQ if SMP
70 select GENERIC_SMP_IDLE_THREAD
71 select GENERIC_STRNCPY_FROM_USER
72 select GENERIC_STRNLEN_USER
73 select GENERIC_TIME_VSYSCALL
74 select HAVE_ACPI_APEI if ACPI
75 select HAVE_ACPI_APEI_NMI if ACPI
76 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
77 select HAVE_AOUT if X86_32
78 select HAVE_ARCH_AUDITSYSCALL
79 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
80 select HAVE_ARCH_JUMP_LABEL
81 select HAVE_ARCH_KASAN if X86_64 && SPARSEMEM_VMEMMAP
83 select HAVE_ARCH_KMEMCHECK
84 select HAVE_ARCH_SECCOMP_FILTER
85 select HAVE_ARCH_SOFT_DIRTY if X86_64
86 select HAVE_ARCH_TRACEHOOK
87 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
88 select HAVE_BPF_JIT if X86_64
89 select HAVE_CC_STACKPROTECTOR
90 select HAVE_CMPXCHG_DOUBLE
91 select HAVE_CMPXCHG_LOCAL
92 select HAVE_CONTEXT_TRACKING if X86_64
93 select HAVE_COPY_THREAD_TLS
94 select HAVE_C_RECORDMCOUNT
95 select HAVE_DEBUG_KMEMLEAK
96 select HAVE_DEBUG_STACKOVERFLOW
97 select HAVE_DMA_API_DEBUG
99 select HAVE_DMA_CONTIGUOUS
100 select HAVE_DYNAMIC_FTRACE
101 select HAVE_DYNAMIC_FTRACE_WITH_REGS
102 select HAVE_EFFICIENT_UNALIGNED_ACCESS
103 select HAVE_FENTRY if X86_64
104 select HAVE_FTRACE_MCOUNT_RECORD
105 select HAVE_FUNCTION_GRAPH_FP_TEST
106 select HAVE_FUNCTION_GRAPH_TRACER
107 select HAVE_FUNCTION_TRACER
108 select HAVE_GENERIC_DMA_COHERENT if X86_32
109 select HAVE_HW_BREAKPOINT
111 select HAVE_IOREMAP_PROT
112 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
113 select HAVE_IRQ_TIME_ACCOUNTING
114 select HAVE_KERNEL_BZIP2
115 select HAVE_KERNEL_GZIP
116 select HAVE_KERNEL_LZ4
117 select HAVE_KERNEL_LZMA
118 select HAVE_KERNEL_LZO
119 select HAVE_KERNEL_XZ
121 select HAVE_KPROBES_ON_FTRACE
122 select HAVE_KRETPROBES
124 select HAVE_LIVEPATCH if X86_64
126 select HAVE_MEMBLOCK_NODE_MAP
127 select HAVE_MIXED_BREAKPOINTS_REGS
129 select HAVE_OPTPROBES
130 select HAVE_PCSPKR_PLATFORM
131 select HAVE_PERF_EVENTS
132 select HAVE_PERF_EVENTS_NMI
133 select HAVE_PERF_REGS
134 select HAVE_PERF_USER_STACK_DUMP
135 select HAVE_REGS_AND_STACK_ACCESS_API
136 select HAVE_SYSCALL_TRACEPOINTS
137 select HAVE_UID16 if X86_32 || IA32_EMULATION
138 select HAVE_UNSTABLE_SCHED_CLOCK
139 select HAVE_USER_RETURN_NOTIFIER
140 select IRQ_FORCED_THREADING
141 select MODULES_USE_ELF_RELA if X86_64
142 select MODULES_USE_ELF_REL if X86_32
143 select OLD_SIGACTION if X86_32
144 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
149 select SYSCTL_EXCEPTION_TRACE
150 select USER_STACKTRACE_SUPPORT
152 select X86_DEV_DMA_OPS if X86_64
153 select X86_FEATURE_NAMES if PROC_FS
155 config INSTRUCTION_DECODER
157 depends on KPROBES || PERF_EVENTS || UPROBES
159 config PERF_EVENTS_INTEL_UNCORE
161 depends on PERF_EVENTS && CPU_SUP_INTEL && PCI
165 default "elf32-i386" if X86_32
166 default "elf64-x86-64" if X86_64
168 config ARCH_DEFCONFIG
170 default "arch/x86/configs/i386_defconfig" if X86_32
171 default "arch/x86/configs/x86_64_defconfig" if X86_64
173 config LOCKDEP_SUPPORT
176 config STACKTRACE_SUPPORT
179 config HAVE_LATENCYTOP_SUPPORT
188 config NEED_DMA_MAP_STATE
190 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
192 config NEED_SG_DMA_LENGTH
195 config GENERIC_ISA_DMA
197 depends on ISA_DMA_API
202 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
204 config GENERIC_BUG_RELATIVE_POINTERS
207 config GENERIC_HWEIGHT
210 config ARCH_MAY_HAVE_PC_FDC
212 depends on ISA_DMA_API
214 config RWSEM_XCHGADD_ALGORITHM
217 config GENERIC_CALIBRATE_DELAY
220 config ARCH_HAS_CPU_RELAX
223 config ARCH_HAS_CACHE_LINE_SIZE
226 config HAVE_SETUP_PER_CPU_AREA
229 config NEED_PER_CPU_EMBED_FIRST_CHUNK
232 config NEED_PER_CPU_PAGE_FIRST_CHUNK
235 config ARCH_HIBERNATION_POSSIBLE
238 config ARCH_SUSPEND_POSSIBLE
241 config ARCH_WANT_HUGE_PMD_SHARE
244 config ARCH_WANT_GENERAL_HUGETLB
253 config ARCH_SUPPORTS_OPTIMIZED_INLINING
256 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
259 config KASAN_SHADOW_OFFSET
262 default 0xdffffc0000000000
264 config HAVE_INTEL_TXT
266 depends on INTEL_IOMMU && ACPI
270 depends on X86_32 && SMP
274 depends on X86_64 && SMP
276 config X86_32_LAZY_GS
278 depends on X86_32 && !CC_STACKPROTECTOR
280 config ARCH_HWEIGHT_CFLAGS
282 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
283 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
285 config ARCH_SUPPORTS_UPROBES
288 config FIX_EARLYCON_MEM
291 config PGTABLE_LEVELS
297 source "init/Kconfig"
298 source "kernel/Kconfig.freezer"
300 menu "Processor type and features"
303 bool "DMA memory allocation support" if EXPERT
306 DMA memory allocation support allows devices with less than 32-bit
307 addressing to allocate within the first 16MB of address space.
308 Disable if no such devices will be used.
313 bool "Symmetric multi-processing support"
315 This enables support for systems with more than one CPU. If you have
316 a system with only one CPU, say N. If you have a system with more
319 If you say N here, the kernel will run on uni- and multiprocessor
320 machines, but will use only one CPU of a multiprocessor machine. If
321 you say Y here, the kernel will run on many, but not all,
322 uniprocessor machines. On a uniprocessor machine, the kernel
323 will run faster if you say N here.
325 Note that if you say Y here and choose architecture "586" or
326 "Pentium" under "Processor family", the kernel will not work on 486
327 architectures. Similarly, multiprocessor kernels for the "PPro"
328 architecture may not work on all Pentium based boards.
330 People using multiprocessor machines who say Y here should also say
331 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
332 Management" code will be disabled if you say Y here.
334 See also <file:Documentation/x86/i386/IO-APIC.txt>,
335 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
336 <http://www.tldp.org/docs.html#howto>.
338 If you don't know what to do here, say N.
340 config X86_FEATURE_NAMES
341 bool "Processor feature human-readable names" if EMBEDDED
344 This option compiles in a table of x86 feature bits and corresponding
345 names. This is required to support /proc/cpuinfo and a few kernel
346 messages. You can disable this to save space, at the expense of
347 making those few kernel messages show numeric feature bits instead.
352 bool "Support x2apic"
353 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
355 This enables x2apic support on CPUs that have this feature.
357 This allows 32-bit apic IDs (so it can support very large systems),
358 and accesses the local apic via MSRs not via mmio.
360 If you don't know what to do here, say N.
363 bool "Enable MPS table" if ACPI || SFI
365 depends on X86_LOCAL_APIC
367 For old smp systems that do not have proper acpi support. Newer systems
368 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
371 bool "Support for big SMP systems with more than 8 CPUs"
372 depends on X86_32 && SMP
374 This option is needed for the systems that have more than 8 CPUs
378 depends on X86_GOLDFISH
381 config X86_EXTENDED_PLATFORM
382 bool "Support for extended (non-PC) x86 platforms"
385 If you disable this option then the kernel will only support
386 standard PC platforms. (which covers the vast majority of
389 If you enable this option then you'll be able to select support
390 for the following (non-PC) 32 bit x86 platforms:
391 Goldfish (Android emulator)
394 SGI 320/540 (Visual Workstation)
395 STA2X11-based (e.g. Northville)
396 Moorestown MID devices
398 If you have one of these systems, or if you want to build a
399 generic distribution kernel, say Y here - otherwise say N.
403 config X86_EXTENDED_PLATFORM
404 bool "Support for extended (non-PC) x86 platforms"
407 If you disable this option then the kernel will only support
408 standard PC platforms. (which covers the vast majority of
411 If you enable this option then you'll be able to select support
412 for the following (non-PC) 64 bit x86 platforms:
417 If you have one of these systems, or if you want to build a
418 generic distribution kernel, say Y here - otherwise say N.
420 # This is an alphabetically sorted list of 64 bit extended platforms
421 # Please maintain the alphabetic order if and when there are additions
423 bool "Numascale NumaChip"
425 depends on X86_EXTENDED_PLATFORM
428 depends on X86_X2APIC
429 depends on PCI_MMCONFIG
431 Adds support for Numascale NumaChip large-SMP systems. Needed to
432 enable more than ~168 cores.
433 If you don't have one of these, you should say N here.
437 select HYPERVISOR_GUEST
439 depends on X86_64 && PCI
440 depends on X86_EXTENDED_PLATFORM
443 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
444 supposed to run on these EM64T-based machines. Only choose this option
445 if you have one of these machines.
448 bool "SGI Ultraviolet"
450 depends on X86_EXTENDED_PLATFORM
452 depends on X86_X2APIC
455 This option is needed in order to support SGI Ultraviolet systems.
456 If you don't have one of these, you should say N here.
458 # Following is an alphabetically sorted list of 32 bit extended platforms
459 # Please maintain the alphabetic order if and when there are additions
462 bool "Goldfish (Virtual Platform)"
463 depends on X86_EXTENDED_PLATFORM
465 Enable support for the Goldfish virtual platform used primarily
466 for Android development. Unless you are building for the Android
467 Goldfish emulator say N here.
470 bool "CE4100 TV platform"
472 depends on PCI_GODIRECT
473 depends on X86_IO_APIC
475 depends on X86_EXTENDED_PLATFORM
476 select X86_REBOOTFIXUPS
478 select OF_EARLY_FLATTREE
480 Select for the Intel CE media processor (CE4100) SOC.
481 This option compiles in support for the CE4100 SOC for settop
482 boxes and media devices.
485 bool "Intel MID platform support"
487 depends on X86_EXTENDED_PLATFORM
488 depends on X86_PLATFORM_DEVICES
491 depends on X86_IO_APIC
497 select MFD_INTEL_MSIC
499 Select to build a kernel capable of supporting Intel MID (Mobile
500 Internet Device) platform systems which do not have the PCI legacy
501 interfaces. If you are building for a PC class system say N here.
503 Intel MID platforms are based on an Intel processor and chipset which
504 consume less power than most of the x86 derivatives.
506 config X86_INTEL_QUARK
507 bool "Intel Quark platform support"
509 depends on X86_EXTENDED_PLATFORM
510 depends on X86_PLATFORM_DEVICES
514 depends on X86_IO_APIC
519 Select to include support for Quark X1000 SoC.
520 Say Y here if you have a Quark based system such as the Arduino
521 compatible Intel Galileo.
523 config X86_INTEL_LPSS
524 bool "Intel Low Power Subsystem Support"
529 Select to build support for Intel Low Power Subsystem such as
530 found on Intel Lynxpoint PCH. Selecting this option enables
531 things like clock tree (common clock framework) and pincontrol
532 which are needed by the LPSS peripheral drivers.
534 config X86_AMD_PLATFORM_DEVICE
535 bool "AMD ACPI2Platform devices support"
540 Select to interpret AMD specific ACPI device to platform device
541 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
542 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
543 implemented under PINCTRL subsystem.
546 tristate "Intel SoC IOSF Sideband support for SoC platforms"
549 This option enables sideband register access support for Intel SoC
550 platforms. On these platforms the IOSF sideband is used in lieu of
551 MSR's for some register accesses, mostly but not limited to thermal
552 and power. Drivers may query the availability of this device to
553 determine if they need the sideband in order to work on these
554 platforms. The sideband is available on the following SoC products.
555 This list is not meant to be exclusive.
560 You should say Y if you are running a kernel on one of these SoC's.
562 config IOSF_MBI_DEBUG
563 bool "Enable IOSF sideband access through debugfs"
564 depends on IOSF_MBI && DEBUG_FS
566 Select this option to expose the IOSF sideband access registers (MCR,
567 MDR, MCRX) through debugfs to write and read register information from
568 different units on the SoC. This is most useful for obtaining device
569 state information for debug and analysis. As this is a general access
570 mechanism, users of this option would have specific knowledge of the
571 device they want to access.
573 If you don't require the option or are in doubt, say N.
576 bool "RDC R-321x SoC"
578 depends on X86_EXTENDED_PLATFORM
580 select X86_REBOOTFIXUPS
582 This option is needed for RDC R-321x system-on-chip, also known
584 If you don't have one of these chips, you should say N here.
586 config X86_32_NON_STANDARD
587 bool "Support non-standard 32-bit SMP architectures"
588 depends on X86_32 && SMP
589 depends on X86_EXTENDED_PLATFORM
591 This option compiles in the bigsmp and STA2X11 default
592 subarchitectures. It is intended for a generic binary
593 kernel. If you select them all, kernel will probe it one by
594 one and will fallback to default.
596 # Alphabetically sorted list of Non standard 32 bit platforms
598 config X86_SUPPORTS_MEMORY_FAILURE
600 # MCE code calls memory_failure():
602 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
603 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
604 depends on X86_64 || !SPARSEMEM
605 select ARCH_SUPPORTS_MEMORY_FAILURE
608 bool "STA2X11 Companion Chip Support"
609 depends on X86_32_NON_STANDARD && PCI
610 select X86_DEV_DMA_OPS
614 select ARCH_REQUIRE_GPIOLIB
617 This adds support for boards based on the STA2X11 IO-Hub,
618 a.k.a. "ConneXt". The chip is used in place of the standard
619 PC chipset, so all "standard" peripherals are missing. If this
620 option is selected the kernel will still be able to boot on
621 standard PC machines.
624 tristate "Eurobraille/Iris poweroff module"
627 The Iris machines from EuroBraille do not have APM or ACPI support
628 to shut themselves down properly. A special I/O sequence is
629 needed to do so, which is what this module does at
632 This is only for Iris machines from EuroBraille.
636 config SCHED_OMIT_FRAME_POINTER
638 prompt "Single-depth WCHAN output"
641 Calculate simpler /proc/<PID>/wchan values. If this option
642 is disabled then wchan values will recurse back to the
643 caller function. This provides more accurate wchan values,
644 at the expense of slightly more scheduling overhead.
646 If in doubt, say "Y".
648 menuconfig HYPERVISOR_GUEST
649 bool "Linux guest support"
651 Say Y here to enable options for running Linux under various hyper-
652 visors. This option enables basic hypervisor detection and platform
655 If you say N, all options in this submenu will be skipped and
656 disabled, and Linux guest support won't be built in.
661 bool "Enable paravirtualization code"
663 This changes the kernel so it can modify itself when it is run
664 under a hypervisor, potentially improving performance significantly
665 over full virtualization. However, when run without a hypervisor
666 the kernel is theoretically slower and slightly larger.
668 config PARAVIRT_DEBUG
669 bool "paravirt-ops debugging"
670 depends on PARAVIRT && DEBUG_KERNEL
672 Enable to debug paravirt_ops internals. Specifically, BUG if
673 a paravirt_op is missing when it is called.
675 config PARAVIRT_SPINLOCKS
676 bool "Paravirtualization layer for spinlocks"
677 depends on PARAVIRT && SMP
678 select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS
680 Paravirtualized spinlocks allow a pvops backend to replace the
681 spinlock implementation with something virtualization-friendly
682 (for example, block the virtual CPU rather than spinning).
684 It has a minimal impact on native kernels and gives a nice performance
685 benefit on paravirtualized KVM / Xen kernels.
687 If you are unsure how to answer this question, answer Y.
689 source "arch/x86/xen/Kconfig"
692 bool "KVM Guest support (including kvmclock)"
694 select PARAVIRT_CLOCK
697 This option enables various optimizations for running under the KVM
698 hypervisor. It includes a paravirtualized clock, so that instead
699 of relying on a PIT (or probably other) emulation by the
700 underlying device model, the host provides the guest with
701 timing infrastructure such as time of day, and system time
704 bool "Enable debug information for KVM Guests in debugfs"
705 depends on KVM_GUEST && DEBUG_FS
708 This option enables collection of various statistics for KVM guest.
709 Statistics are displayed in debugfs filesystem. Enabling this option
710 may incur significant overhead.
712 source "arch/x86/lguest/Kconfig"
714 config PARAVIRT_TIME_ACCOUNTING
715 bool "Paravirtual steal time accounting"
719 Select this option to enable fine granularity task steal time
720 accounting. Time spent executing other tasks in parallel with
721 the current vCPU is discounted from the vCPU power. To account for
722 that, there can be a small performance impact.
724 If in doubt, say N here.
726 config PARAVIRT_CLOCK
729 endif #HYPERVISOR_GUEST
734 source "arch/x86/Kconfig.cpu"
738 prompt "HPET Timer Support" if X86_32
740 Use the IA-PC HPET (High Precision Event Timer) to manage
741 time in preference to the PIT and RTC, if a HPET is
743 HPET is the next generation timer replacing legacy 8254s.
744 The HPET provides a stable time base on SMP
745 systems, unlike the TSC, but it is more expensive to access,
746 as it is off-chip. You can find the HPET spec at
747 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
749 You can safely choose Y here. However, HPET will only be
750 activated if the platform and the BIOS support this feature.
751 Otherwise the 8254 will be used for timing services.
753 Choose N to continue using the legacy 8254 timer.
755 config HPET_EMULATE_RTC
757 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
760 def_bool y if X86_INTEL_MID
761 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
763 depends on X86_INTEL_MID && SFI
765 APB timer is the replacement for 8254, HPET on X86 MID platforms.
766 The APBT provides a stable time base on SMP
767 systems, unlike the TSC, but it is more expensive to access,
768 as it is off-chip. APB timers are always running regardless of CPU
769 C states, they are used as per CPU clockevent device when possible.
771 # Mark as expert because too many people got it wrong.
772 # The code disables itself when not needed.
775 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
776 bool "Enable DMI scanning" if EXPERT
778 Enabled scanning of DMI to identify machine quirks. Say Y
779 here unless you have verified that your setup is not
780 affected by entries in the DMI blacklist. Required by PNP
784 bool "Old AMD GART IOMMU support"
786 depends on X86_64 && PCI && AMD_NB
788 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
789 GART based hardware IOMMUs.
791 The GART supports full DMA access for devices with 32-bit access
792 limitations, on systems with more than 3 GB. This is usually needed
793 for USB, sound, many IDE/SATA chipsets and some other devices.
795 Newer systems typically have a modern AMD IOMMU, supported via
796 the CONFIG_AMD_IOMMU=y config option.
798 In normal configurations this driver is only active when needed:
799 there's more than 3 GB of memory and the system contains a
800 32-bit limited device.
805 bool "IBM Calgary IOMMU support"
807 depends on X86_64 && PCI
809 Support for hardware IOMMUs in IBM's xSeries x366 and x460
810 systems. Needed to run systems with more than 3GB of memory
811 properly with 32-bit PCI devices that do not support DAC
812 (Double Address Cycle). Calgary also supports bus level
813 isolation, where all DMAs pass through the IOMMU. This
814 prevents them from going anywhere except their intended
815 destination. This catches hard-to-find kernel bugs and
816 mis-behaving drivers and devices that do not use the DMA-API
817 properly to set up their DMA buffers. The IOMMU can be
818 turned off at boot time with the iommu=off parameter.
819 Normally the kernel will make the right choice by itself.
822 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
824 prompt "Should Calgary be enabled by default?"
825 depends on CALGARY_IOMMU
827 Should Calgary be enabled by default? if you choose 'y', Calgary
828 will be used (if it exists). If you choose 'n', Calgary will not be
829 used even if it exists. If you choose 'n' and would like to use
830 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
833 # need this always selected by IOMMU for the VIA workaround
837 Support for software bounce buffers used on x86-64 systems
838 which don't have a hardware IOMMU. Using this PCI devices
839 which can only access 32-bits of memory can be used on systems
840 with more than 3 GB of memory.
845 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
848 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
849 depends on X86_64 && SMP && DEBUG_KERNEL
850 select CPUMASK_OFFSTACK
852 Enable maximum number of CPUS and NUMA Nodes for this architecture.
856 int "Maximum number of CPUs" if SMP && !MAXSMP
857 range 2 8 if SMP && X86_32 && !X86_BIGSMP
858 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
859 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
861 default "8192" if MAXSMP
862 default "32" if SMP && X86_BIGSMP
863 default "8" if SMP && X86_32
866 This allows you to specify the maximum number of CPUs which this
867 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
868 supported value is 8192, otherwise the maximum value is 512. The
869 minimum value which makes sense is 2.
871 This is purely to save memory - each supported CPU adds
872 approximately eight kilobytes to the kernel image.
875 bool "SMT (Hyperthreading) scheduler support"
878 SMT scheduler support improves the CPU scheduler's decision making
879 when dealing with Intel Pentium 4 chips with HyperThreading at a
880 cost of slightly increased overhead in some places. If unsure say
885 prompt "Multi-core scheduler support"
888 Multi-core scheduler support improves the CPU scheduler's decision
889 making when dealing with multi-core CPU chips at a cost of slightly
890 increased overhead in some places. If unsure say N here.
892 source "kernel/Kconfig.preempt"
896 depends on !SMP && X86_LOCAL_APIC
899 bool "Local APIC support on uniprocessors" if !PCI_MSI
901 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
903 A local APIC (Advanced Programmable Interrupt Controller) is an
904 integrated interrupt controller in the CPU. If you have a single-CPU
905 system which has a processor with a local APIC, you can say Y here to
906 enable and use it. If you say Y here even though your machine doesn't
907 have a local APIC, then the kernel will still run with no slowdown at
908 all. The local APIC supports CPU-generated self-interrupts (timer,
909 performance counters), and the NMI watchdog which detects hard
913 bool "IO-APIC support on uniprocessors"
914 depends on X86_UP_APIC
916 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
917 SMP-capable replacement for PC-style interrupt controllers. Most
918 SMP systems and many recent uniprocessor systems have one.
920 If you have a single-CPU system with an IO-APIC, you can say Y here
921 to use it. If you say Y here even though your machine doesn't have
922 an IO-APIC, then the kernel will still run with no slowdown at all.
924 config X86_LOCAL_APIC
926 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
927 select IRQ_DOMAIN_HIERARCHY
928 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
932 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
934 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
935 bool "Reroute for broken boot IRQs"
936 depends on X86_IO_APIC
938 This option enables a workaround that fixes a source of
939 spurious interrupts. This is recommended when threaded
940 interrupt handling is used on systems where the generation of
941 superfluous "boot interrupts" cannot be disabled.
943 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
944 entry in the chipset's IO-APIC is masked (as, e.g. the RT
945 kernel does during interrupt handling). On chipsets where this
946 boot IRQ generation cannot be disabled, this workaround keeps
947 the original IRQ line masked so that only the equivalent "boot
948 IRQ" is delivered to the CPUs. The workaround also tells the
949 kernel to set up the IRQ handler on the boot IRQ line. In this
950 way only one interrupt is delivered to the kernel. Otherwise
951 the spurious second interrupt may cause the kernel to bring
952 down (vital) interrupt lines.
954 Only affects "broken" chipsets. Interrupt sharing may be
955 increased on these systems.
958 bool "Machine Check / overheating reporting"
959 select GENERIC_ALLOCATOR
962 Machine Check support allows the processor to notify the
963 kernel if it detects a problem (e.g. overheating, data corruption).
964 The action the kernel takes depends on the severity of the problem,
965 ranging from warning messages to halting the machine.
969 prompt "Intel MCE features"
970 depends on X86_MCE && X86_LOCAL_APIC
972 Additional support for intel specific MCE features such as
977 prompt "AMD MCE features"
978 depends on X86_MCE && X86_LOCAL_APIC
980 Additional support for AMD specific MCE features such as
981 the DRAM Error Threshold.
983 config X86_ANCIENT_MCE
984 bool "Support for old Pentium 5 / WinChip machine checks"
985 depends on X86_32 && X86_MCE
987 Include support for machine check handling on old Pentium 5 or WinChip
988 systems. These typically need to be enabled explicitly on the command
991 config X86_MCE_THRESHOLD
992 depends on X86_MCE_AMD || X86_MCE_INTEL
995 config X86_MCE_INJECT
997 tristate "Machine check injector support"
999 Provide support for injecting machine checks for testing purposes.
1000 If you don't know what a machine check is and you don't do kernel
1001 QA it is safe to say n.
1003 config X86_THERMAL_VECTOR
1005 depends on X86_MCE_INTEL
1007 config X86_LEGACY_VM86
1008 bool "Legacy VM86 support (obsolete)"
1012 This option allows user programs to put the CPU into V8086
1013 mode, which is an 80286-era approximation of 16-bit real mode.
1015 Some very old versions of X and/or vbetool require this option
1016 for user mode setting. Similarly, DOSEMU will use it if
1017 available to accelerate real mode DOS programs. However, any
1018 recent version of DOSEMU, X, or vbetool should be fully
1019 functional even without kernel VM86 support, as they will all
1020 fall back to (pretty well performing) software emulation.
1022 Anything that works on a 64-bit kernel is unlikely to need
1023 this option, as 64-bit kernels don't, and can't, support V8086
1024 mode. This option is also unrelated to 16-bit protected mode
1025 and is not needed to run most 16-bit programs under Wine.
1027 Enabling this option adds considerable attack surface to the
1028 kernel and slows down system calls and exception handling.
1030 Unless you use very old userspace or need the last drop of
1031 performance in your real mode DOS games and can't use KVM,
1036 default X86_LEGACY_VM86
1039 bool "Enable support for 16-bit segments" if EXPERT
1041 depends on MODIFY_LDT_SYSCALL
1043 This option is required by programs like Wine to run 16-bit
1044 protected mode legacy code on x86 processors. Disabling
1045 this option saves about 300 bytes on i386, or around 6K text
1046 plus 16K runtime memory on x86-64,
1050 depends on X86_16BIT && X86_32
1054 depends on X86_16BIT && X86_64
1056 config X86_VSYSCALL_EMULATION
1057 bool "Enable vsyscall emulation" if EXPERT
1061 This enables emulation of the legacy vsyscall page. Disabling
1062 it is roughly equivalent to booting with vsyscall=none, except
1063 that it will also disable the helpful warning if a program
1064 tries to use a vsyscall. With this option set to N, offending
1065 programs will just segfault, citing addresses of the form
1068 This option is required by many programs built before 2013, and
1069 care should be used even with newer programs if set to N.
1071 Disabling this option saves about 7K of kernel size and
1072 possibly 4K of additional runtime pagetable memory.
1075 tristate "Toshiba Laptop support"
1078 This adds a driver to safely access the System Management Mode of
1079 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1080 not work on models with a Phoenix BIOS. The System Management Mode
1081 is used to set the BIOS and power saving options on Toshiba portables.
1083 For information on utilities to make use of this driver see the
1084 Toshiba Linux utilities web site at:
1085 <http://www.buzzard.org.uk/toshiba/>.
1087 Say Y if you intend to run this kernel on a Toshiba portable.
1091 tristate "Dell i8k legacy laptop support"
1093 select SENSORS_DELL_SMM
1095 This option enables legacy /proc/i8k userspace interface in hwmon
1096 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1097 temperature and allows controlling fan speeds of Dell laptops via
1098 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1099 it reports also power and hotkey status. For fan speed control is
1100 needed userspace package i8kutils.
1102 Say Y if you intend to run this kernel on old Dell laptops or want to
1103 use userspace package i8kutils.
1106 config X86_REBOOTFIXUPS
1107 bool "Enable X86 board specific fixups for reboot"
1110 This enables chipset and/or board specific fixups to be done
1111 in order to get reboot to work correctly. This is only needed on
1112 some combinations of hardware and BIOS. The symptom, for which
1113 this config is intended, is when reboot ends with a stalled/hung
1116 Currently, the only fixup is for the Geode machines using
1117 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1119 Say Y if you want to enable the fixup. Currently, it's safe to
1120 enable this option even if you don't need it.
1124 tristate "CPU microcode loading support"
1125 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1129 If you say Y here, you will be able to update the microcode on
1130 certain Intel and AMD processors. The Intel support is for the
1131 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1132 Xeon etc. The AMD support is for families 0x10 and later. You will
1133 obviously need the actual microcode binary data itself which is not
1134 shipped with the Linux kernel.
1136 This option selects the general module only, you need to select
1137 at least one vendor specific module as well.
1139 To compile this driver as a module, choose M here: the module
1140 will be called microcode.
1142 config MICROCODE_INTEL
1143 bool "Intel microcode loading support"
1144 depends on MICROCODE
1148 This options enables microcode patch loading support for Intel
1151 For the current Intel microcode data package go to
1152 <https://downloadcenter.intel.com> and search for
1153 'Linux Processor Microcode Data File'.
1155 config MICROCODE_AMD
1156 bool "AMD microcode loading support"
1157 depends on MICROCODE
1160 If you select this option, microcode patch loading support for AMD
1161 processors will be enabled.
1163 config MICROCODE_OLD_INTERFACE
1165 depends on MICROCODE
1167 config MICROCODE_INTEL_EARLY
1170 config MICROCODE_AMD_EARLY
1173 config MICROCODE_EARLY
1174 bool "Early load microcode"
1175 depends on MICROCODE=y && BLK_DEV_INITRD
1176 select MICROCODE_INTEL_EARLY if MICROCODE_INTEL
1177 select MICROCODE_AMD_EARLY if MICROCODE_AMD
1180 This option provides functionality to read additional microcode data
1181 at the beginning of initrd image. The data tells kernel to load
1182 microcode to CPU's as early as possible. No functional change if no
1183 microcode data is glued to the initrd, therefore it's safe to say Y.
1186 tristate "/dev/cpu/*/msr - Model-specific register support"
1188 This device gives privileged processes access to the x86
1189 Model-Specific Registers (MSRs). It is a character device with
1190 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1191 MSR accesses are directed to a specific CPU on multi-processor
1195 tristate "/dev/cpu/*/cpuid - CPU information support"
1197 This device gives processes access to the x86 CPUID instruction to
1198 be executed on a specific processor. It is a character device
1199 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1203 prompt "High Memory Support"
1210 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1211 However, the address space of 32-bit x86 processors is only 4
1212 Gigabytes large. That means that, if you have a large amount of
1213 physical memory, not all of it can be "permanently mapped" by the
1214 kernel. The physical memory that's not permanently mapped is called
1217 If you are compiling a kernel which will never run on a machine with
1218 more than 1 Gigabyte total physical RAM, answer "off" here (default
1219 choice and suitable for most users). This will result in a "3GB/1GB"
1220 split: 3GB are mapped so that each process sees a 3GB virtual memory
1221 space and the remaining part of the 4GB virtual memory space is used
1222 by the kernel to permanently map as much physical memory as
1225 If the machine has between 1 and 4 Gigabytes physical RAM, then
1228 If more than 4 Gigabytes is used then answer "64GB" here. This
1229 selection turns Intel PAE (Physical Address Extension) mode on.
1230 PAE implements 3-level paging on IA32 processors. PAE is fully
1231 supported by Linux, PAE mode is implemented on all recent Intel
1232 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1233 then the kernel will not boot on CPUs that don't support PAE!
1235 The actual amount of total physical memory will either be
1236 auto detected or can be forced by using a kernel command line option
1237 such as "mem=256M". (Try "man bootparam" or see the documentation of
1238 your boot loader (lilo or loadlin) about how to pass options to the
1239 kernel at boot time.)
1241 If unsure, say "off".
1246 Select this if you have a 32-bit processor and between 1 and 4
1247 gigabytes of physical RAM.
1254 Select this if you have a 32-bit processor and more than 4
1255 gigabytes of physical RAM.
1260 prompt "Memory split" if EXPERT
1264 Select the desired split between kernel and user memory.
1266 If the address range available to the kernel is less than the
1267 physical memory installed, the remaining memory will be available
1268 as "high memory". Accessing high memory is a little more costly
1269 than low memory, as it needs to be mapped into the kernel first.
1270 Note that increasing the kernel address space limits the range
1271 available to user programs, making the address space there
1272 tighter. Selecting anything other than the default 3G/1G split
1273 will also likely make your kernel incompatible with binary-only
1276 If you are not absolutely sure what you are doing, leave this
1280 bool "3G/1G user/kernel split"
1281 config VMSPLIT_3G_OPT
1283 bool "3G/1G user/kernel split (for full 1G low memory)"
1285 bool "2G/2G user/kernel split"
1286 config VMSPLIT_2G_OPT
1288 bool "2G/2G user/kernel split (for full 2G low memory)"
1290 bool "1G/3G user/kernel split"
1295 default 0xB0000000 if VMSPLIT_3G_OPT
1296 default 0x80000000 if VMSPLIT_2G
1297 default 0x78000000 if VMSPLIT_2G_OPT
1298 default 0x40000000 if VMSPLIT_1G
1304 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1307 bool "PAE (Physical Address Extension) Support"
1308 depends on X86_32 && !HIGHMEM4G
1310 PAE is required for NX support, and furthermore enables
1311 larger swapspace support for non-overcommit purposes. It
1312 has the cost of more pagetable lookup overhead, and also
1313 consumes more pagetable space per process.
1315 config ARCH_PHYS_ADDR_T_64BIT
1317 depends on X86_64 || X86_PAE
1319 config ARCH_DMA_ADDR_T_64BIT
1321 depends on X86_64 || HIGHMEM64G
1323 config X86_DIRECT_GBPAGES
1325 depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1327 Certain kernel features effectively disable kernel
1328 linear 1 GB mappings (even if the CPU otherwise
1329 supports them), so don't confuse the user by printing
1330 that we have them enabled.
1332 # Common NUMA Features
1334 bool "Numa Memory Allocation and Scheduler Support"
1336 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1337 default y if X86_BIGSMP
1339 Enable NUMA (Non Uniform Memory Access) support.
1341 The kernel will try to allocate memory used by a CPU on the
1342 local memory controller of the CPU and add some more
1343 NUMA awareness to the kernel.
1345 For 64-bit this is recommended if the system is Intel Core i7
1346 (or later), AMD Opteron, or EM64T NUMA.
1348 For 32-bit this is only needed if you boot a 32-bit
1349 kernel on a 64-bit NUMA platform.
1351 Otherwise, you should say N.
1355 prompt "Old style AMD Opteron NUMA detection"
1356 depends on X86_64 && NUMA && PCI
1358 Enable AMD NUMA node topology detection. You should say Y here if
1359 you have a multi processor AMD system. This uses an old method to
1360 read the NUMA configuration directly from the builtin Northbridge
1361 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1362 which also takes priority if both are compiled in.
1364 config X86_64_ACPI_NUMA
1366 prompt "ACPI NUMA detection"
1367 depends on X86_64 && NUMA && ACPI && PCI
1370 Enable ACPI SRAT based node topology detection.
1372 # Some NUMA nodes have memory ranges that span
1373 # other nodes. Even though a pfn is valid and
1374 # between a node's start and end pfns, it may not
1375 # reside on that node. See memmap_init_zone()
1377 config NODES_SPAN_OTHER_NODES
1379 depends on X86_64_ACPI_NUMA
1382 bool "NUMA emulation"
1385 Enable NUMA emulation. A flat machine will be split
1386 into virtual nodes when booted with "numa=fake=N", where N is the
1387 number of nodes. This is only useful for debugging.
1390 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1392 default "10" if MAXSMP
1393 default "6" if X86_64
1395 depends on NEED_MULTIPLE_NODES
1397 Specify the maximum number of NUMA Nodes available on the target
1398 system. Increases memory reserved to accommodate various tables.
1400 config ARCH_HAVE_MEMORY_PRESENT
1402 depends on X86_32 && DISCONTIGMEM
1404 config NEED_NODE_MEMMAP_SIZE
1406 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1408 config ARCH_FLATMEM_ENABLE
1410 depends on X86_32 && !NUMA
1412 config ARCH_DISCONTIGMEM_ENABLE
1414 depends on NUMA && X86_32
1416 config ARCH_DISCONTIGMEM_DEFAULT
1418 depends on NUMA && X86_32
1420 config ARCH_SPARSEMEM_ENABLE
1422 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1423 select SPARSEMEM_STATIC if X86_32
1424 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1426 config ARCH_SPARSEMEM_DEFAULT
1430 config ARCH_SELECT_MEMORY_MODEL
1432 depends on ARCH_SPARSEMEM_ENABLE
1434 config ARCH_MEMORY_PROBE
1435 bool "Enable sysfs memory/probe interface"
1436 depends on X86_64 && MEMORY_HOTPLUG
1438 This option enables a sysfs memory/probe interface for testing.
1439 See Documentation/memory-hotplug.txt for more information.
1440 If you are unsure how to answer this question, answer N.
1442 config ARCH_PROC_KCORE_TEXT
1444 depends on X86_64 && PROC_KCORE
1446 config ILLEGAL_POINTER_VALUE
1449 default 0xdead000000000000 if X86_64
1453 config X86_PMEM_LEGACY
1454 bool "Support non-standard NVDIMMs and ADR protected memory"
1455 depends on PHYS_ADDR_T_64BIT
1459 Treat memory marked using the non-standard e820 type of 12 as used
1460 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1461 The kernel will offer these regions to the 'pmem' driver so
1462 they can be used for persistent storage.
1467 bool "Allocate 3rd-level pagetables from highmem"
1470 The VM uses one page table entry for each page of physical memory.
1471 For systems with a lot of RAM, this can be wasteful of precious
1472 low memory. Setting this option will put user-space page table
1473 entries in high memory.
1475 config X86_CHECK_BIOS_CORRUPTION
1476 bool "Check for low memory corruption"
1478 Periodically check for memory corruption in low memory, which
1479 is suspected to be caused by BIOS. Even when enabled in the
1480 configuration, it is disabled at runtime. Enable it by
1481 setting "memory_corruption_check=1" on the kernel command
1482 line. By default it scans the low 64k of memory every 60
1483 seconds; see the memory_corruption_check_size and
1484 memory_corruption_check_period parameters in
1485 Documentation/kernel-parameters.txt to adjust this.
1487 When enabled with the default parameters, this option has
1488 almost no overhead, as it reserves a relatively small amount
1489 of memory and scans it infrequently. It both detects corruption
1490 and prevents it from affecting the running system.
1492 It is, however, intended as a diagnostic tool; if repeatable
1493 BIOS-originated corruption always affects the same memory,
1494 you can use memmap= to prevent the kernel from using that
1497 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1498 bool "Set the default setting of memory_corruption_check"
1499 depends on X86_CHECK_BIOS_CORRUPTION
1502 Set whether the default state of memory_corruption_check is
1505 config X86_RESERVE_LOW
1506 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1510 Specify the amount of low memory to reserve for the BIOS.
1512 The first page contains BIOS data structures that the kernel
1513 must not use, so that page must always be reserved.
1515 By default we reserve the first 64K of physical RAM, as a
1516 number of BIOSes are known to corrupt that memory range
1517 during events such as suspend/resume or monitor cable
1518 insertion, so it must not be used by the kernel.
1520 You can set this to 4 if you are absolutely sure that you
1521 trust the BIOS to get all its memory reservations and usages
1522 right. If you know your BIOS have problems beyond the
1523 default 64K area, you can set this to 640 to avoid using the
1524 entire low memory range.
1526 If you have doubts about the BIOS (e.g. suspend/resume does
1527 not work or there's kernel crashes after certain hardware
1528 hotplug events) then you might want to enable
1529 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1530 typical corruption patterns.
1532 Leave this to the default value of 64 if you are unsure.
1534 config MATH_EMULATION
1536 depends on MODIFY_LDT_SYSCALL
1537 prompt "Math emulation" if X86_32
1539 Linux can emulate a math coprocessor (used for floating point
1540 operations) if you don't have one. 486DX and Pentium processors have
1541 a math coprocessor built in, 486SX and 386 do not, unless you added
1542 a 487DX or 387, respectively. (The messages during boot time can
1543 give you some hints here ["man dmesg"].) Everyone needs either a
1544 coprocessor or this emulation.
1546 If you don't have a math coprocessor, you need to say Y here; if you
1547 say Y here even though you have a coprocessor, the coprocessor will
1548 be used nevertheless. (This behavior can be changed with the kernel
1549 command line option "no387", which comes handy if your coprocessor
1550 is broken. Try "man bootparam" or see the documentation of your boot
1551 loader (lilo or loadlin) about how to pass options to the kernel at
1552 boot time.) This means that it is a good idea to say Y here if you
1553 intend to use this kernel on different machines.
1555 More information about the internals of the Linux math coprocessor
1556 emulation can be found in <file:arch/x86/math-emu/README>.
1558 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1559 kernel, it won't hurt.
1563 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1565 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1566 the Memory Type Range Registers (MTRRs) may be used to control
1567 processor access to memory ranges. This is most useful if you have
1568 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1569 allows bus write transfers to be combined into a larger transfer
1570 before bursting over the PCI/AGP bus. This can increase performance
1571 of image write operations 2.5 times or more. Saying Y here creates a
1572 /proc/mtrr file which may be used to manipulate your processor's
1573 MTRRs. Typically the X server should use this.
1575 This code has a reasonably generic interface so that similar
1576 control registers on other processors can be easily supported
1579 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1580 Registers (ARRs) which provide a similar functionality to MTRRs. For
1581 these, the ARRs are used to emulate the MTRRs.
1582 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1583 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1584 write-combining. All of these processors are supported by this code
1585 and it makes sense to say Y here if you have one of them.
1587 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1588 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1589 can lead to all sorts of problems, so it's good to say Y here.
1591 You can safely say Y even if your machine doesn't have MTRRs, you'll
1592 just add about 9 KB to your kernel.
1594 See <file:Documentation/x86/mtrr.txt> for more information.
1596 config MTRR_SANITIZER
1598 prompt "MTRR cleanup support"
1601 Convert MTRR layout from continuous to discrete, so X drivers can
1602 add writeback entries.
1604 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1605 The largest mtrr entry size for a continuous block can be set with
1610 config MTRR_SANITIZER_ENABLE_DEFAULT
1611 int "MTRR cleanup enable value (0-1)"
1614 depends on MTRR_SANITIZER
1616 Enable mtrr cleanup default value
1618 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1619 int "MTRR cleanup spare reg num (0-7)"
1622 depends on MTRR_SANITIZER
1624 mtrr cleanup spare entries default, it can be changed via
1625 mtrr_spare_reg_nr=N on the kernel command line.
1629 prompt "x86 PAT support" if EXPERT
1632 Use PAT attributes to setup page level cache control.
1634 PATs are the modern equivalents of MTRRs and are much more
1635 flexible than MTRRs.
1637 Say N here if you see bootup problems (boot crash, boot hang,
1638 spontaneous reboots) or a non-working video driver.
1642 config ARCH_USES_PG_UNCACHED
1648 prompt "x86 architectural random number generator" if EXPERT
1650 Enable the x86 architectural RDRAND instruction
1651 (Intel Bull Mountain technology) to generate random numbers.
1652 If supported, this is a high bandwidth, cryptographically
1653 secure hardware random number generator.
1657 prompt "Supervisor Mode Access Prevention" if EXPERT
1659 Supervisor Mode Access Prevention (SMAP) is a security
1660 feature in newer Intel processors. There is a small
1661 performance cost if this enabled and turned on; there is
1662 also a small increase in the kernel size if this is enabled.
1666 config X86_INTEL_MPX
1667 prompt "Intel MPX (Memory Protection Extensions)"
1669 depends on CPU_SUP_INTEL
1671 MPX provides hardware features that can be used in
1672 conjunction with compiler-instrumented code to check
1673 memory references. It is designed to detect buffer
1674 overflow or underflow bugs.
1676 This option enables running applications which are
1677 instrumented or otherwise use MPX. It does not use MPX
1678 itself inside the kernel or to protect the kernel
1679 against bad memory references.
1681 Enabling this option will make the kernel larger:
1682 ~8k of kernel text and 36 bytes of data on a 64-bit
1683 defconfig. It adds a long to the 'mm_struct' which
1684 will increase the kernel memory overhead of each
1685 process and adds some branches to paths used during
1686 exec() and munmap().
1688 For details, see Documentation/x86/intel_mpx.txt
1693 bool "EFI runtime service support"
1696 select EFI_RUNTIME_WRAPPERS
1698 This enables the kernel to use EFI runtime services that are
1699 available (such as the EFI variable services).
1701 This option is only useful on systems that have EFI firmware.
1702 In addition, you should use the latest ELILO loader available
1703 at <http://elilo.sourceforge.net> in order to take advantage
1704 of EFI runtime services. However, even with this option, the
1705 resultant kernel should continue to boot on existing non-EFI
1709 bool "EFI stub support"
1710 depends on EFI && !X86_USE_3DNOW
1713 This kernel feature allows a bzImage to be loaded directly
1714 by EFI firmware without the use of a bootloader.
1716 See Documentation/efi-stub.txt for more information.
1719 bool "EFI mixed-mode support"
1720 depends on EFI_STUB && X86_64
1722 Enabling this feature allows a 64-bit kernel to be booted
1723 on a 32-bit firmware, provided that your CPU supports 64-bit
1726 Note that it is not possible to boot a mixed-mode enabled
1727 kernel via the EFI boot stub - a bootloader that supports
1728 the EFI handover protocol must be used.
1734 prompt "Enable seccomp to safely compute untrusted bytecode"
1736 This kernel feature is useful for number crunching applications
1737 that may need to compute untrusted bytecode during their
1738 execution. By using pipes or other transports made available to
1739 the process as file descriptors supporting the read/write
1740 syscalls, it's possible to isolate those applications in
1741 their own address space using seccomp. Once seccomp is
1742 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1743 and the task is only allowed to execute a few safe syscalls
1744 defined by each seccomp mode.
1746 If unsure, say Y. Only embedded should say N here.
1748 source kernel/Kconfig.hz
1751 bool "kexec system call"
1753 kexec is a system call that implements the ability to shutdown your
1754 current kernel, and to start another kernel. It is like a reboot
1755 but it is independent of the system firmware. And like a reboot
1756 you can start any kernel with it, not just Linux.
1758 The name comes from the similarity to the exec system call.
1760 It is an ongoing process to be certain the hardware in a machine
1761 is properly shutdown, so do not be surprised if this code does not
1762 initially work for you. As of this writing the exact hardware
1763 interface is strongly in flux, so no good recommendation can be
1767 bool "kexec file based system call"
1772 depends on CRYPTO_SHA256=y
1774 This is new version of kexec system call. This system call is
1775 file based and takes file descriptors as system call argument
1776 for kernel and initramfs as opposed to list of segments as
1777 accepted by previous system call.
1779 config KEXEC_VERIFY_SIG
1780 bool "Verify kernel signature during kexec_file_load() syscall"
1781 depends on KEXEC_FILE
1783 This option makes kernel signature verification mandatory for
1784 the kexec_file_load() syscall.
1786 In addition to that option, you need to enable signature
1787 verification for the corresponding kernel image type being
1788 loaded in order for this to work.
1790 config KEXEC_BZIMAGE_VERIFY_SIG
1791 bool "Enable bzImage signature verification support"
1792 depends on KEXEC_VERIFY_SIG
1793 depends on SIGNED_PE_FILE_VERIFICATION
1794 select SYSTEM_TRUSTED_KEYRING
1796 Enable bzImage signature verification support.
1799 bool "kernel crash dumps"
1800 depends on X86_64 || (X86_32 && HIGHMEM)
1802 Generate crash dump after being started by kexec.
1803 This should be normally only set in special crash dump kernels
1804 which are loaded in the main kernel with kexec-tools into
1805 a specially reserved region and then later executed after
1806 a crash by kdump/kexec. The crash dump kernel must be compiled
1807 to a memory address not used by the main kernel or BIOS using
1808 PHYSICAL_START, or it must be built as a relocatable image
1809 (CONFIG_RELOCATABLE=y).
1810 For more details see Documentation/kdump/kdump.txt
1814 depends on KEXEC && HIBERNATION
1816 Jump between original kernel and kexeced kernel and invoke
1817 code in physical address mode via KEXEC
1819 config PHYSICAL_START
1820 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1823 This gives the physical address where the kernel is loaded.
1825 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1826 bzImage will decompress itself to above physical address and
1827 run from there. Otherwise, bzImage will run from the address where
1828 it has been loaded by the boot loader and will ignore above physical
1831 In normal kdump cases one does not have to set/change this option
1832 as now bzImage can be compiled as a completely relocatable image
1833 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1834 address. This option is mainly useful for the folks who don't want
1835 to use a bzImage for capturing the crash dump and want to use a
1836 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1837 to be specifically compiled to run from a specific memory area
1838 (normally a reserved region) and this option comes handy.
1840 So if you are using bzImage for capturing the crash dump,
1841 leave the value here unchanged to 0x1000000 and set
1842 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1843 for capturing the crash dump change this value to start of
1844 the reserved region. In other words, it can be set based on
1845 the "X" value as specified in the "crashkernel=YM@XM"
1846 command line boot parameter passed to the panic-ed
1847 kernel. Please take a look at Documentation/kdump/kdump.txt
1848 for more details about crash dumps.
1850 Usage of bzImage for capturing the crash dump is recommended as
1851 one does not have to build two kernels. Same kernel can be used
1852 as production kernel and capture kernel. Above option should have
1853 gone away after relocatable bzImage support is introduced. But it
1854 is present because there are users out there who continue to use
1855 vmlinux for dump capture. This option should go away down the
1858 Don't change this unless you know what you are doing.
1861 bool "Build a relocatable kernel"
1864 This builds a kernel image that retains relocation information
1865 so it can be loaded someplace besides the default 1MB.
1866 The relocations tend to make the kernel binary about 10% larger,
1867 but are discarded at runtime.
1869 One use is for the kexec on panic case where the recovery kernel
1870 must live at a different physical address than the primary
1873 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1874 it has been loaded at and the compile time physical address
1875 (CONFIG_PHYSICAL_START) is used as the minimum location.
1877 config RANDOMIZE_BASE
1878 bool "Randomize the address of the kernel image"
1879 depends on RELOCATABLE
1882 Randomizes the physical and virtual address at which the
1883 kernel image is decompressed, as a security feature that
1884 deters exploit attempts relying on knowledge of the location
1885 of kernel internals.
1887 Entropy is generated using the RDRAND instruction if it is
1888 supported. If RDTSC is supported, it is used as well. If
1889 neither RDRAND nor RDTSC are supported, then randomness is
1890 read from the i8254 timer.
1892 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1893 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1894 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1895 minimum of 2MiB, only 10 bits of entropy is theoretically
1896 possible. At best, due to page table layouts, 64-bit can use
1897 9 bits of entropy and 32-bit uses 8 bits.
1901 config RANDOMIZE_BASE_MAX_OFFSET
1902 hex "Maximum kASLR offset allowed" if EXPERT
1903 depends on RANDOMIZE_BASE
1904 range 0x0 0x20000000 if X86_32
1905 default "0x20000000" if X86_32
1906 range 0x0 0x40000000 if X86_64
1907 default "0x40000000" if X86_64
1909 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1910 memory is used to determine the maximal offset in bytes that will
1911 be applied to the kernel when kernel Address Space Layout
1912 Randomization (kASLR) is active. This must be a multiple of
1915 On 32-bit this is limited to 512MiB by page table layouts. The
1918 On 64-bit this is limited by how the kernel fixmap page table is
1919 positioned, so this cannot be larger than 1GiB currently. Without
1920 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1921 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1922 modules area will shrink to compensate, up to the current maximum
1923 1GiB to 1GiB split. The default is 1GiB.
1925 If unsure, leave at the default value.
1927 # Relocation on x86 needs some additional build support
1928 config X86_NEED_RELOCS
1930 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1932 config PHYSICAL_ALIGN
1933 hex "Alignment value to which kernel should be aligned"
1935 range 0x2000 0x1000000 if X86_32
1936 range 0x200000 0x1000000 if X86_64
1938 This value puts the alignment restrictions on physical address
1939 where kernel is loaded and run from. Kernel is compiled for an
1940 address which meets above alignment restriction.
1942 If bootloader loads the kernel at a non-aligned address and
1943 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1944 address aligned to above value and run from there.
1946 If bootloader loads the kernel at a non-aligned address and
1947 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1948 load address and decompress itself to the address it has been
1949 compiled for and run from there. The address for which kernel is
1950 compiled already meets above alignment restrictions. Hence the
1951 end result is that kernel runs from a physical address meeting
1952 above alignment restrictions.
1954 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1955 this value must be a multiple of 0x200000.
1957 Don't change this unless you know what you are doing.
1960 bool "Support for hot-pluggable CPUs"
1963 Say Y here to allow turning CPUs off and on. CPUs can be
1964 controlled through /sys/devices/system/cpu.
1965 ( Note: power management support will enable this option
1966 automatically on SMP systems. )
1967 Say N if you want to disable CPU hotplug.
1969 config BOOTPARAM_HOTPLUG_CPU0
1970 bool "Set default setting of cpu0_hotpluggable"
1972 depends on HOTPLUG_CPU
1974 Set whether default state of cpu0_hotpluggable is on or off.
1976 Say Y here to enable CPU0 hotplug by default. If this switch
1977 is turned on, there is no need to give cpu0_hotplug kernel
1978 parameter and the CPU0 hotplug feature is enabled by default.
1980 Please note: there are two known CPU0 dependencies if you want
1981 to enable the CPU0 hotplug feature either by this switch or by
1982 cpu0_hotplug kernel parameter.
1984 First, resume from hibernate or suspend always starts from CPU0.
1985 So hibernate and suspend are prevented if CPU0 is offline.
1987 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1988 offline if any interrupt can not migrate out of CPU0. There may
1989 be other CPU0 dependencies.
1991 Please make sure the dependencies are under your control before
1992 you enable this feature.
1994 Say N if you don't want to enable CPU0 hotplug feature by default.
1995 You still can enable the CPU0 hotplug feature at boot by kernel
1996 parameter cpu0_hotplug.
1998 config DEBUG_HOTPLUG_CPU0
2000 prompt "Debug CPU0 hotplug"
2001 depends on HOTPLUG_CPU
2003 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2004 soon as possible and boots up userspace with CPU0 offlined. User
2005 can online CPU0 back after boot time.
2007 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2008 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2009 compilation or giving cpu0_hotplug kernel parameter at boot.
2015 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2016 depends on X86_32 || IA32_EMULATION
2018 Certain buggy versions of glibc will crash if they are
2019 presented with a 32-bit vDSO that is not mapped at the address
2020 indicated in its segment table.
2022 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2023 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2024 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2025 the only released version with the bug, but OpenSUSE 9
2026 contains a buggy "glibc 2.3.2".
2028 The symptom of the bug is that everything crashes on startup, saying:
2029 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2031 Saying Y here changes the default value of the vdso32 boot
2032 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2033 This works around the glibc bug but hurts performance.
2035 If unsure, say N: if you are compiling your own kernel, you
2036 are unlikely to be using a buggy version of glibc.
2039 bool "Built-in kernel command line"
2041 Allow for specifying boot arguments to the kernel at
2042 build time. On some systems (e.g. embedded ones), it is
2043 necessary or convenient to provide some or all of the
2044 kernel boot arguments with the kernel itself (that is,
2045 to not rely on the boot loader to provide them.)
2047 To compile command line arguments into the kernel,
2048 set this option to 'Y', then fill in the
2049 boot arguments in CONFIG_CMDLINE.
2051 Systems with fully functional boot loaders (i.e. non-embedded)
2052 should leave this option set to 'N'.
2055 string "Built-in kernel command string"
2056 depends on CMDLINE_BOOL
2059 Enter arguments here that should be compiled into the kernel
2060 image and used at boot time. If the boot loader provides a
2061 command line at boot time, it is appended to this string to
2062 form the full kernel command line, when the system boots.
2064 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2065 change this behavior.
2067 In most cases, the command line (whether built-in or provided
2068 by the boot loader) should specify the device for the root
2071 config CMDLINE_OVERRIDE
2072 bool "Built-in command line overrides boot loader arguments"
2073 depends on CMDLINE_BOOL
2075 Set this option to 'Y' to have the kernel ignore the boot loader
2076 command line, and use ONLY the built-in command line.
2078 This is used to work around broken boot loaders. This should
2079 be set to 'N' under normal conditions.
2081 config MODIFY_LDT_SYSCALL
2082 bool "Enable the LDT (local descriptor table)" if EXPERT
2085 Linux can allow user programs to install a per-process x86
2086 Local Descriptor Table (LDT) using the modify_ldt(2) system
2087 call. This is required to run 16-bit or segmented code such as
2088 DOSEMU or some Wine programs. It is also used by some very old
2089 threading libraries.
2091 Enabling this feature adds a small amount of overhead to
2092 context switches and increases the low-level kernel attack
2093 surface. Disabling it removes the modify_ldt(2) system call.
2095 Saying 'N' here may make sense for embedded or server kernels.
2097 source "kernel/livepatch/Kconfig"
2101 config ARCH_ENABLE_MEMORY_HOTPLUG
2103 depends on X86_64 || (X86_32 && HIGHMEM)
2105 config ARCH_ENABLE_MEMORY_HOTREMOVE
2107 depends on MEMORY_HOTPLUG
2109 config USE_PERCPU_NUMA_NODE_ID
2113 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2115 depends on X86_64 || X86_PAE
2117 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2119 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2121 menu "Power management and ACPI options"
2123 config ARCH_HIBERNATION_HEADER
2125 depends on X86_64 && HIBERNATION
2127 source "kernel/power/Kconfig"
2129 source "drivers/acpi/Kconfig"
2131 source "drivers/sfi/Kconfig"
2138 tristate "APM (Advanced Power Management) BIOS support"
2139 depends on X86_32 && PM_SLEEP
2141 APM is a BIOS specification for saving power using several different
2142 techniques. This is mostly useful for battery powered laptops with
2143 APM compliant BIOSes. If you say Y here, the system time will be
2144 reset after a RESUME operation, the /proc/apm device will provide
2145 battery status information, and user-space programs will receive
2146 notification of APM "events" (e.g. battery status change).
2148 If you select "Y" here, you can disable actual use of the APM
2149 BIOS by passing the "apm=off" option to the kernel at boot time.
2151 Note that the APM support is almost completely disabled for
2152 machines with more than one CPU.
2154 In order to use APM, you will need supporting software. For location
2155 and more information, read <file:Documentation/power/apm-acpi.txt>
2156 and the Battery Powered Linux mini-HOWTO, available from
2157 <http://www.tldp.org/docs.html#howto>.
2159 This driver does not spin down disk drives (see the hdparm(8)
2160 manpage ("man 8 hdparm") for that), and it doesn't turn off
2161 VESA-compliant "green" monitors.
2163 This driver does not support the TI 4000M TravelMate and the ACER
2164 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2165 desktop machines also don't have compliant BIOSes, and this driver
2166 may cause those machines to panic during the boot phase.
2168 Generally, if you don't have a battery in your machine, there isn't
2169 much point in using this driver and you should say N. If you get
2170 random kernel OOPSes or reboots that don't seem to be related to
2171 anything, try disabling/enabling this option (or disabling/enabling
2174 Some other things you should try when experiencing seemingly random,
2177 1) make sure that you have enough swap space and that it is
2179 2) pass the "no-hlt" option to the kernel
2180 3) switch on floating point emulation in the kernel and pass
2181 the "no387" option to the kernel
2182 4) pass the "floppy=nodma" option to the kernel
2183 5) pass the "mem=4M" option to the kernel (thereby disabling
2184 all but the first 4 MB of RAM)
2185 6) make sure that the CPU is not over clocked.
2186 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2187 8) disable the cache from your BIOS settings
2188 9) install a fan for the video card or exchange video RAM
2189 10) install a better fan for the CPU
2190 11) exchange RAM chips
2191 12) exchange the motherboard.
2193 To compile this driver as a module, choose M here: the
2194 module will be called apm.
2198 config APM_IGNORE_USER_SUSPEND
2199 bool "Ignore USER SUSPEND"
2201 This option will ignore USER SUSPEND requests. On machines with a
2202 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2203 series notebooks, it is necessary to say Y because of a BIOS bug.
2205 config APM_DO_ENABLE
2206 bool "Enable PM at boot time"
2208 Enable APM features at boot time. From page 36 of the APM BIOS
2209 specification: "When disabled, the APM BIOS does not automatically
2210 power manage devices, enter the Standby State, enter the Suspend
2211 State, or take power saving steps in response to CPU Idle calls."
2212 This driver will make CPU Idle calls when Linux is idle (unless this
2213 feature is turned off -- see "Do CPU IDLE calls", below). This
2214 should always save battery power, but more complicated APM features
2215 will be dependent on your BIOS implementation. You may need to turn
2216 this option off if your computer hangs at boot time when using APM
2217 support, or if it beeps continuously instead of suspending. Turn
2218 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2219 T400CDT. This is off by default since most machines do fine without
2224 bool "Make CPU Idle calls when idle"
2226 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2227 On some machines, this can activate improved power savings, such as
2228 a slowed CPU clock rate, when the machine is idle. These idle calls
2229 are made after the idle loop has run for some length of time (e.g.,
2230 333 mS). On some machines, this will cause a hang at boot time or
2231 whenever the CPU becomes idle. (On machines with more than one CPU,
2232 this option does nothing.)
2234 config APM_DISPLAY_BLANK
2235 bool "Enable console blanking using APM"
2237 Enable console blanking using the APM. Some laptops can use this to
2238 turn off the LCD backlight when the screen blanker of the Linux
2239 virtual console blanks the screen. Note that this is only used by
2240 the virtual console screen blanker, and won't turn off the backlight
2241 when using the X Window system. This also doesn't have anything to
2242 do with your VESA-compliant power-saving monitor. Further, this
2243 option doesn't work for all laptops -- it might not turn off your
2244 backlight at all, or it might print a lot of errors to the console,
2245 especially if you are using gpm.
2247 config APM_ALLOW_INTS
2248 bool "Allow interrupts during APM BIOS calls"
2250 Normally we disable external interrupts while we are making calls to
2251 the APM BIOS as a measure to lessen the effects of a badly behaving
2252 BIOS implementation. The BIOS should reenable interrupts if it
2253 needs to. Unfortunately, some BIOSes do not -- especially those in
2254 many of the newer IBM Thinkpads. If you experience hangs when you
2255 suspend, try setting this to Y. Otherwise, say N.
2259 source "drivers/cpufreq/Kconfig"
2261 source "drivers/cpuidle/Kconfig"
2263 source "drivers/idle/Kconfig"
2268 menu "Bus options (PCI etc.)"
2274 Find out whether you have a PCI motherboard. PCI is the name of a
2275 bus system, i.e. the way the CPU talks to the other stuff inside
2276 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2277 VESA. If you have PCI, say Y, otherwise N.
2280 prompt "PCI access mode"
2281 depends on X86_32 && PCI
2284 On PCI systems, the BIOS can be used to detect the PCI devices and
2285 determine their configuration. However, some old PCI motherboards
2286 have BIOS bugs and may crash if this is done. Also, some embedded
2287 PCI-based systems don't have any BIOS at all. Linux can also try to
2288 detect the PCI hardware directly without using the BIOS.
2290 With this option, you can specify how Linux should detect the
2291 PCI devices. If you choose "BIOS", the BIOS will be used,
2292 if you choose "Direct", the BIOS won't be used, and if you
2293 choose "MMConfig", then PCI Express MMCONFIG will be used.
2294 If you choose "Any", the kernel will try MMCONFIG, then the
2295 direct access method and falls back to the BIOS if that doesn't
2296 work. If unsure, go with the default, which is "Any".
2301 config PCI_GOMMCONFIG
2318 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2320 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2323 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2327 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2331 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2335 depends on PCI && XEN
2343 bool "Support mmconfig PCI config space access"
2344 depends on X86_64 && PCI && ACPI
2346 config PCI_CNB20LE_QUIRK
2347 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2350 Read the PCI windows out of the CNB20LE host bridge. This allows
2351 PCI hotplug to work on systems with the CNB20LE chipset which do
2354 There's no public spec for this chipset, and this functionality
2355 is known to be incomplete.
2357 You should say N unless you know you need this.
2359 source "drivers/pci/pcie/Kconfig"
2361 source "drivers/pci/Kconfig"
2363 # x86_64 have no ISA slots, but can have ISA-style DMA.
2365 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2368 Enables ISA-style DMA support for devices requiring such controllers.
2376 Find out whether you have ISA slots on your motherboard. ISA is the
2377 name of a bus system, i.e. the way the CPU talks to the other stuff
2378 inside your box. Other bus systems are PCI, EISA, MicroChannel
2379 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2380 newer boards don't support it. If you have ISA, say Y, otherwise N.
2386 The Extended Industry Standard Architecture (EISA) bus was
2387 developed as an open alternative to the IBM MicroChannel bus.
2389 The EISA bus provided some of the features of the IBM MicroChannel
2390 bus while maintaining backward compatibility with cards made for
2391 the older ISA bus. The EISA bus saw limited use between 1988 and
2392 1995 when it was made obsolete by the PCI bus.
2394 Say Y here if you are building a kernel for an EISA-based machine.
2398 source "drivers/eisa/Kconfig"
2401 tristate "NatSemi SCx200 support"
2403 This provides basic support for National Semiconductor's
2404 (now AMD's) Geode processors. The driver probes for the
2405 PCI-IDs of several on-chip devices, so its a good dependency
2406 for other scx200_* drivers.
2408 If compiled as a module, the driver is named scx200.
2410 config SCx200HR_TIMER
2411 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2415 This driver provides a clocksource built upon the on-chip
2416 27MHz high-resolution timer. Its also a workaround for
2417 NSC Geode SC-1100's buggy TSC, which loses time when the
2418 processor goes idle (as is done by the scheduler). The
2419 other workaround is idle=poll boot option.
2422 bool "One Laptop Per Child support"
2429 Add support for detecting the unique features of the OLPC
2433 bool "OLPC XO-1 Power Management"
2434 depends on OLPC && MFD_CS5535 && PM_SLEEP
2437 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2440 bool "OLPC XO-1 Real Time Clock"
2441 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2443 Add support for the XO-1 real time clock, which can be used as a
2444 programmable wakeup source.
2447 bool "OLPC XO-1 SCI extras"
2448 depends on OLPC && OLPC_XO1_PM
2454 Add support for SCI-based features of the OLPC XO-1 laptop:
2455 - EC-driven system wakeups
2459 - AC adapter status updates
2460 - Battery status updates
2462 config OLPC_XO15_SCI
2463 bool "OLPC XO-1.5 SCI extras"
2464 depends on OLPC && ACPI
2467 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2468 - EC-driven system wakeups
2469 - AC adapter status updates
2470 - Battery status updates
2473 bool "PCEngines ALIX System Support (LED setup)"
2476 This option enables system support for the PCEngines ALIX.
2477 At present this just sets up LEDs for GPIO control on
2478 ALIX2/3/6 boards. However, other system specific setup should
2481 Note: You must still enable the drivers for GPIO and LED support
2482 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2484 Note: You have to set alix.force=1 for boards with Award BIOS.
2487 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2490 This option enables system support for the Soekris Engineering net5501.
2493 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2497 This option enables system support for the Traverse Technologies GEOS.
2500 bool "Technologic Systems TS-5500 platform support"
2502 select CHECK_SIGNATURE
2506 This option enables system support for the Technologic Systems TS-5500.
2512 depends on CPU_SUP_AMD && PCI
2514 source "drivers/pcmcia/Kconfig"
2516 source "drivers/pci/hotplug/Kconfig"
2519 tristate "RapidIO support"
2523 If enabled this option will include drivers and the core
2524 infrastructure code to support RapidIO interconnect devices.
2526 source "drivers/rapidio/Kconfig"
2529 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2531 Firmwares often provide initial graphics framebuffers so the BIOS,
2532 bootloader or kernel can show basic video-output during boot for
2533 user-guidance and debugging. Historically, x86 used the VESA BIOS
2534 Extensions and EFI-framebuffers for this, which are mostly limited
2536 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2537 framebuffers so the new generic system-framebuffer drivers can be
2538 used on x86. If the framebuffer is not compatible with the generic
2539 modes, it is adverticed as fallback platform framebuffer so legacy
2540 drivers like efifb, vesafb and uvesafb can pick it up.
2541 If this option is not selected, all system framebuffers are always
2542 marked as fallback platform framebuffers as usual.
2544 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2545 not be able to pick up generic system framebuffers if this option
2546 is selected. You are highly encouraged to enable simplefb as
2547 replacement if you select this option. simplefb can correctly deal
2548 with generic system framebuffers. But you should still keep vesafb
2549 and others enabled as fallback if a system framebuffer is
2550 incompatible with simplefb.
2557 menu "Executable file formats / Emulations"
2559 source "fs/Kconfig.binfmt"
2561 config IA32_EMULATION
2562 bool "IA32 Emulation"
2565 select COMPAT_BINFMT_ELF
2566 select ARCH_WANT_OLD_COMPAT_IPC
2568 Include code to run legacy 32-bit programs under a
2569 64-bit kernel. You should likely turn this on, unless you're
2570 100% sure that you don't have any 32-bit programs left.
2573 tristate "IA32 a.out support"
2574 depends on IA32_EMULATION
2576 Support old a.out binaries in the 32bit emulation.
2579 bool "x32 ABI for 64-bit mode"
2582 Include code to run binaries for the x32 native 32-bit ABI
2583 for 64-bit processors. An x32 process gets access to the
2584 full 64-bit register file and wide data path while leaving
2585 pointers at 32 bits for smaller memory footprint.
2587 You will need a recent binutils (2.22 or later) with
2588 elf32_x86_64 support enabled to compile a kernel with this
2593 depends on IA32_EMULATION || X86_X32
2596 config COMPAT_FOR_U64_ALIGNMENT
2599 config SYSVIPC_COMPAT
2611 config HAVE_ATOMIC_IOMAP
2615 config X86_DEV_DMA_OPS
2617 depends on X86_64 || STA2X11
2619 config X86_DMA_REMAP
2627 source "net/Kconfig"
2629 source "drivers/Kconfig"
2631 source "drivers/firmware/Kconfig"
2635 source "arch/x86/Kconfig.debug"
2637 source "security/Kconfig"
2639 source "crypto/Kconfig"
2641 source "arch/x86/kvm/Kconfig"
2643 source "lib/Kconfig"