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 if X86_64
31 select ARCH_HAS_MMIO_FLUSH
32 select ARCH_HAS_SG_CHAIN
33 select ARCH_HAVE_NMI_SAFE_CMPXCHG
34 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
35 select ARCH_MIGHT_HAVE_PC_PARPORT
36 select ARCH_MIGHT_HAVE_PC_SERIO
37 select ARCH_SUPPORTS_ATOMIC_RMW
38 select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
39 select ARCH_SUPPORTS_INT128 if X86_64
40 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
41 select ARCH_USE_BUILTIN_BSWAP
42 select ARCH_USE_CMPXCHG_LOCKREF if X86_64
43 select ARCH_USE_QUEUED_RWLOCKS
44 select ARCH_USE_QUEUED_SPINLOCKS
45 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if SMP
46 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
47 select ARCH_WANT_FRAME_POINTERS
48 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
49 select ARCH_WANT_OPTIONAL_GPIOLIB
50 select BUILDTIME_EXTABLE_SORT
52 select CLKSRC_I8253 if X86_32
53 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
54 select CLOCKSOURCE_WATCHDOG
55 select CLONE_BACKWARDS if X86_32
56 select COMPAT_OLD_SIGACTION if IA32_EMULATION
57 select DCACHE_WORD_ACCESS
58 select EDAC_ATOMIC_SCRUB
60 select GENERIC_CLOCKEVENTS
61 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
62 select GENERIC_CLOCKEVENTS_MIN_ADJUST
63 select GENERIC_CMOS_UPDATE
64 select GENERIC_CPU_AUTOPROBE
65 select GENERIC_EARLY_IOREMAP
66 select GENERIC_FIND_FIRST_BIT
68 select GENERIC_IRQ_PROBE
69 select GENERIC_IRQ_SHOW
70 select GENERIC_PENDING_IRQ if SMP
71 select GENERIC_SMP_IDLE_THREAD
72 select GENERIC_STRNCPY_FROM_USER
73 select GENERIC_STRNLEN_USER
74 select GENERIC_TIME_VSYSCALL
75 select HAVE_ACPI_APEI if ACPI
76 select HAVE_ACPI_APEI_NMI if ACPI
77 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
78 select HAVE_AOUT if X86_32
79 select HAVE_ARCH_AUDITSYSCALL
80 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
81 select HAVE_ARCH_JUMP_LABEL
82 select HAVE_ARCH_KASAN if X86_64 && SPARSEMEM_VMEMMAP
84 select HAVE_ARCH_KMEMCHECK
85 select HAVE_ARCH_SECCOMP_FILTER
86 select HAVE_ARCH_SOFT_DIRTY if X86_64
87 select HAVE_ARCH_TRACEHOOK
88 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
89 select HAVE_BPF_JIT if X86_64
90 select HAVE_CC_STACKPROTECTOR
91 select HAVE_CMPXCHG_DOUBLE
92 select HAVE_CMPXCHG_LOCAL
93 select HAVE_CONTEXT_TRACKING if X86_64
94 select HAVE_COPY_THREAD_TLS
95 select HAVE_C_RECORDMCOUNT
96 select HAVE_DEBUG_KMEMLEAK
97 select HAVE_DEBUG_STACKOVERFLOW
98 select HAVE_DMA_API_DEBUG
100 select HAVE_DMA_CONTIGUOUS
101 select HAVE_DYNAMIC_FTRACE
102 select HAVE_DYNAMIC_FTRACE_WITH_REGS
103 select HAVE_EFFICIENT_UNALIGNED_ACCESS
104 select HAVE_FENTRY if X86_64
105 select HAVE_FTRACE_MCOUNT_RECORD
106 select HAVE_FUNCTION_GRAPH_FP_TEST
107 select HAVE_FUNCTION_GRAPH_TRACER
108 select HAVE_FUNCTION_TRACER
109 select HAVE_GENERIC_DMA_COHERENT if X86_32
110 select HAVE_HW_BREAKPOINT
112 select HAVE_IOREMAP_PROT
113 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
114 select HAVE_IRQ_TIME_ACCOUNTING
115 select HAVE_KERNEL_BZIP2
116 select HAVE_KERNEL_GZIP
117 select HAVE_KERNEL_LZ4
118 select HAVE_KERNEL_LZMA
119 select HAVE_KERNEL_LZO
120 select HAVE_KERNEL_XZ
122 select HAVE_KPROBES_ON_FTRACE
123 select HAVE_KRETPROBES
125 select HAVE_LIVEPATCH if X86_64
127 select HAVE_MEMBLOCK_NODE_MAP
128 select HAVE_MIXED_BREAKPOINTS_REGS
130 select HAVE_OPTPROBES
131 select HAVE_PCSPKR_PLATFORM
132 select HAVE_PERF_EVENTS
133 select HAVE_PERF_EVENTS_NMI
134 select HAVE_PERF_REGS
135 select HAVE_PERF_USER_STACK_DUMP
136 select HAVE_REGS_AND_STACK_ACCESS_API
137 select HAVE_SYSCALL_TRACEPOINTS
138 select HAVE_UID16 if X86_32 || IA32_EMULATION
139 select HAVE_UNSTABLE_SCHED_CLOCK
140 select HAVE_USER_RETURN_NOTIFIER
141 select IRQ_FORCED_THREADING
142 select MODULES_USE_ELF_RELA if X86_64
143 select MODULES_USE_ELF_REL if X86_32
144 select OLD_SIGACTION if X86_32
145 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
150 select SYSCTL_EXCEPTION_TRACE
151 select USER_STACKTRACE_SUPPORT
153 select X86_DEV_DMA_OPS if X86_64
154 select X86_FEATURE_NAMES if PROC_FS
156 config INSTRUCTION_DECODER
158 depends on KPROBES || PERF_EVENTS || UPROBES
160 config PERF_EVENTS_INTEL_UNCORE
162 depends on PERF_EVENTS && CPU_SUP_INTEL && PCI
166 default "elf32-i386" if X86_32
167 default "elf64-x86-64" if X86_64
169 config ARCH_DEFCONFIG
171 default "arch/x86/configs/i386_defconfig" if X86_32
172 default "arch/x86/configs/x86_64_defconfig" if X86_64
174 config LOCKDEP_SUPPORT
177 config STACKTRACE_SUPPORT
180 config HAVE_LATENCYTOP_SUPPORT
189 config NEED_DMA_MAP_STATE
191 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
193 config NEED_SG_DMA_LENGTH
196 config GENERIC_ISA_DMA
198 depends on ISA_DMA_API
203 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
205 config GENERIC_BUG_RELATIVE_POINTERS
208 config GENERIC_HWEIGHT
211 config ARCH_MAY_HAVE_PC_FDC
213 depends on ISA_DMA_API
215 config RWSEM_XCHGADD_ALGORITHM
218 config GENERIC_CALIBRATE_DELAY
221 config ARCH_HAS_CPU_RELAX
224 config ARCH_HAS_CACHE_LINE_SIZE
227 config HAVE_SETUP_PER_CPU_AREA
230 config NEED_PER_CPU_EMBED_FIRST_CHUNK
233 config NEED_PER_CPU_PAGE_FIRST_CHUNK
236 config ARCH_HIBERNATION_POSSIBLE
239 config ARCH_SUSPEND_POSSIBLE
242 config ARCH_WANT_HUGE_PMD_SHARE
245 config ARCH_WANT_GENERAL_HUGETLB
254 config ARCH_SUPPORTS_OPTIMIZED_INLINING
257 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
260 config KASAN_SHADOW_OFFSET
263 default 0xdffffc0000000000
265 config HAVE_INTEL_TXT
267 depends on INTEL_IOMMU && ACPI
271 depends on X86_32 && SMP
275 depends on X86_64 && SMP
277 config X86_32_LAZY_GS
279 depends on X86_32 && !CC_STACKPROTECTOR
281 config ARCH_HWEIGHT_CFLAGS
283 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
284 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
286 config ARCH_SUPPORTS_UPROBES
289 config FIX_EARLYCON_MEM
292 config PGTABLE_LEVELS
298 source "init/Kconfig"
299 source "kernel/Kconfig.freezer"
301 menu "Processor type and features"
304 bool "DMA memory allocation support" if EXPERT
307 DMA memory allocation support allows devices with less than 32-bit
308 addressing to allocate within the first 16MB of address space.
309 Disable if no such devices will be used.
314 bool "Symmetric multi-processing support"
316 This enables support for systems with more than one CPU. If you have
317 a system with only one CPU, say N. If you have a system with more
320 If you say N here, the kernel will run on uni- and multiprocessor
321 machines, but will use only one CPU of a multiprocessor machine. If
322 you say Y here, the kernel will run on many, but not all,
323 uniprocessor machines. On a uniprocessor machine, the kernel
324 will run faster if you say N here.
326 Note that if you say Y here and choose architecture "586" or
327 "Pentium" under "Processor family", the kernel will not work on 486
328 architectures. Similarly, multiprocessor kernels for the "PPro"
329 architecture may not work on all Pentium based boards.
331 People using multiprocessor machines who say Y here should also say
332 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
333 Management" code will be disabled if you say Y here.
335 See also <file:Documentation/x86/i386/IO-APIC.txt>,
336 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
337 <http://www.tldp.org/docs.html#howto>.
339 If you don't know what to do here, say N.
341 config X86_FEATURE_NAMES
342 bool "Processor feature human-readable names" if EMBEDDED
345 This option compiles in a table of x86 feature bits and corresponding
346 names. This is required to support /proc/cpuinfo and a few kernel
347 messages. You can disable this to save space, at the expense of
348 making those few kernel messages show numeric feature bits instead.
353 bool "Support x2apic"
354 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
356 This enables x2apic support on CPUs that have this feature.
358 This allows 32-bit apic IDs (so it can support very large systems),
359 and accesses the local apic via MSRs not via mmio.
361 If you don't know what to do here, say N.
364 bool "Enable MPS table" if ACPI || SFI
366 depends on X86_LOCAL_APIC
368 For old smp systems that do not have proper acpi support. Newer systems
369 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
372 bool "Support for big SMP systems with more than 8 CPUs"
373 depends on X86_32 && SMP
375 This option is needed for the systems that have more than 8 CPUs
379 depends on X86_GOLDFISH
382 config X86_EXTENDED_PLATFORM
383 bool "Support for extended (non-PC) x86 platforms"
386 If you disable this option then the kernel will only support
387 standard PC platforms. (which covers the vast majority of
390 If you enable this option then you'll be able to select support
391 for the following (non-PC) 32 bit x86 platforms:
392 Goldfish (Android emulator)
395 SGI 320/540 (Visual Workstation)
396 STA2X11-based (e.g. Northville)
397 Moorestown MID devices
399 If you have one of these systems, or if you want to build a
400 generic distribution kernel, say Y here - otherwise say N.
404 config X86_EXTENDED_PLATFORM
405 bool "Support for extended (non-PC) x86 platforms"
408 If you disable this option then the kernel will only support
409 standard PC platforms. (which covers the vast majority of
412 If you enable this option then you'll be able to select support
413 for the following (non-PC) 64 bit x86 platforms:
418 If you have one of these systems, or if you want to build a
419 generic distribution kernel, say Y here - otherwise say N.
421 # This is an alphabetically sorted list of 64 bit extended platforms
422 # Please maintain the alphabetic order if and when there are additions
424 bool "Numascale NumaChip"
426 depends on X86_EXTENDED_PLATFORM
429 depends on X86_X2APIC
430 depends on PCI_MMCONFIG
432 Adds support for Numascale NumaChip large-SMP systems. Needed to
433 enable more than ~168 cores.
434 If you don't have one of these, you should say N here.
438 select HYPERVISOR_GUEST
440 depends on X86_64 && PCI
441 depends on X86_EXTENDED_PLATFORM
444 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
445 supposed to run on these EM64T-based machines. Only choose this option
446 if you have one of these machines.
449 bool "SGI Ultraviolet"
451 depends on X86_EXTENDED_PLATFORM
453 depends on X86_X2APIC
456 This option is needed in order to support SGI Ultraviolet systems.
457 If you don't have one of these, you should say N here.
459 # Following is an alphabetically sorted list of 32 bit extended platforms
460 # Please maintain the alphabetic order if and when there are additions
463 bool "Goldfish (Virtual Platform)"
464 depends on X86_EXTENDED_PLATFORM
466 Enable support for the Goldfish virtual platform used primarily
467 for Android development. Unless you are building for the Android
468 Goldfish emulator say N here.
471 bool "CE4100 TV platform"
473 depends on PCI_GODIRECT
474 depends on X86_IO_APIC
476 depends on X86_EXTENDED_PLATFORM
477 select X86_REBOOTFIXUPS
479 select OF_EARLY_FLATTREE
481 Select for the Intel CE media processor (CE4100) SOC.
482 This option compiles in support for the CE4100 SOC for settop
483 boxes and media devices.
486 bool "Intel MID platform support"
488 depends on X86_EXTENDED_PLATFORM
489 depends on X86_PLATFORM_DEVICES
492 depends on X86_IO_APIC
498 select MFD_INTEL_MSIC
500 Select to build a kernel capable of supporting Intel MID (Mobile
501 Internet Device) platform systems which do not have the PCI legacy
502 interfaces. If you are building for a PC class system say N here.
504 Intel MID platforms are based on an Intel processor and chipset which
505 consume less power than most of the x86 derivatives.
507 config X86_INTEL_QUARK
508 bool "Intel Quark platform support"
510 depends on X86_EXTENDED_PLATFORM
511 depends on X86_PLATFORM_DEVICES
515 depends on X86_IO_APIC
520 Select to include support for Quark X1000 SoC.
521 Say Y here if you have a Quark based system such as the Arduino
522 compatible Intel Galileo.
524 config X86_INTEL_LPSS
525 bool "Intel Low Power Subsystem Support"
530 Select to build support for Intel Low Power Subsystem such as
531 found on Intel Lynxpoint PCH. Selecting this option enables
532 things like clock tree (common clock framework) and pincontrol
533 which are needed by the LPSS peripheral drivers.
535 config X86_AMD_PLATFORM_DEVICE
536 bool "AMD ACPI2Platform devices support"
541 Select to interpret AMD specific ACPI device to platform device
542 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
543 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
544 implemented under PINCTRL subsystem.
547 tristate "Intel SoC IOSF Sideband support for SoC platforms"
550 This option enables sideband register access support for Intel SoC
551 platforms. On these platforms the IOSF sideband is used in lieu of
552 MSR's for some register accesses, mostly but not limited to thermal
553 and power. Drivers may query the availability of this device to
554 determine if they need the sideband in order to work on these
555 platforms. The sideband is available on the following SoC products.
556 This list is not meant to be exclusive.
561 You should say Y if you are running a kernel on one of these SoC's.
563 config IOSF_MBI_DEBUG
564 bool "Enable IOSF sideband access through debugfs"
565 depends on IOSF_MBI && DEBUG_FS
567 Select this option to expose the IOSF sideband access registers (MCR,
568 MDR, MCRX) through debugfs to write and read register information from
569 different units on the SoC. This is most useful for obtaining device
570 state information for debug and analysis. As this is a general access
571 mechanism, users of this option would have specific knowledge of the
572 device they want to access.
574 If you don't require the option or are in doubt, say N.
577 bool "RDC R-321x SoC"
579 depends on X86_EXTENDED_PLATFORM
581 select X86_REBOOTFIXUPS
583 This option is needed for RDC R-321x system-on-chip, also known
585 If you don't have one of these chips, you should say N here.
587 config X86_32_NON_STANDARD
588 bool "Support non-standard 32-bit SMP architectures"
589 depends on X86_32 && SMP
590 depends on X86_EXTENDED_PLATFORM
592 This option compiles in the bigsmp and STA2X11 default
593 subarchitectures. It is intended for a generic binary
594 kernel. If you select them all, kernel will probe it one by
595 one and will fallback to default.
597 # Alphabetically sorted list of Non standard 32 bit platforms
599 config X86_SUPPORTS_MEMORY_FAILURE
601 # MCE code calls memory_failure():
603 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
604 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
605 depends on X86_64 || !SPARSEMEM
606 select ARCH_SUPPORTS_MEMORY_FAILURE
609 bool "STA2X11 Companion Chip Support"
610 depends on X86_32_NON_STANDARD && PCI
611 select X86_DEV_DMA_OPS
615 select ARCH_REQUIRE_GPIOLIB
618 This adds support for boards based on the STA2X11 IO-Hub,
619 a.k.a. "ConneXt". The chip is used in place of the standard
620 PC chipset, so all "standard" peripherals are missing. If this
621 option is selected the kernel will still be able to boot on
622 standard PC machines.
625 tristate "Eurobraille/Iris poweroff module"
628 The Iris machines from EuroBraille do not have APM or ACPI support
629 to shut themselves down properly. A special I/O sequence is
630 needed to do so, which is what this module does at
633 This is only for Iris machines from EuroBraille.
637 config SCHED_OMIT_FRAME_POINTER
639 prompt "Single-depth WCHAN output"
642 Calculate simpler /proc/<PID>/wchan values. If this option
643 is disabled then wchan values will recurse back to the
644 caller function. This provides more accurate wchan values,
645 at the expense of slightly more scheduling overhead.
647 If in doubt, say "Y".
649 menuconfig HYPERVISOR_GUEST
650 bool "Linux guest support"
652 Say Y here to enable options for running Linux under various hyper-
653 visors. This option enables basic hypervisor detection and platform
656 If you say N, all options in this submenu will be skipped and
657 disabled, and Linux guest support won't be built in.
662 bool "Enable paravirtualization code"
664 This changes the kernel so it can modify itself when it is run
665 under a hypervisor, potentially improving performance significantly
666 over full virtualization. However, when run without a hypervisor
667 the kernel is theoretically slower and slightly larger.
669 config PARAVIRT_DEBUG
670 bool "paravirt-ops debugging"
671 depends on PARAVIRT && DEBUG_KERNEL
673 Enable to debug paravirt_ops internals. Specifically, BUG if
674 a paravirt_op is missing when it is called.
676 config PARAVIRT_SPINLOCKS
677 bool "Paravirtualization layer for spinlocks"
678 depends on PARAVIRT && SMP
679 select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS
681 Paravirtualized spinlocks allow a pvops backend to replace the
682 spinlock implementation with something virtualization-friendly
683 (for example, block the virtual CPU rather than spinning).
685 It has a minimal impact on native kernels and gives a nice performance
686 benefit on paravirtualized KVM / Xen kernels.
688 If you are unsure how to answer this question, answer Y.
690 source "arch/x86/xen/Kconfig"
693 bool "KVM Guest support (including kvmclock)"
695 select PARAVIRT_CLOCK
698 This option enables various optimizations for running under the KVM
699 hypervisor. It includes a paravirtualized clock, so that instead
700 of relying on a PIT (or probably other) emulation by the
701 underlying device model, the host provides the guest with
702 timing infrastructure such as time of day, and system time
705 bool "Enable debug information for KVM Guests in debugfs"
706 depends on KVM_GUEST && DEBUG_FS
709 This option enables collection of various statistics for KVM guest.
710 Statistics are displayed in debugfs filesystem. Enabling this option
711 may incur significant overhead.
713 source "arch/x86/lguest/Kconfig"
715 config PARAVIRT_TIME_ACCOUNTING
716 bool "Paravirtual steal time accounting"
720 Select this option to enable fine granularity task steal time
721 accounting. Time spent executing other tasks in parallel with
722 the current vCPU is discounted from the vCPU power. To account for
723 that, there can be a small performance impact.
725 If in doubt, say N here.
727 config PARAVIRT_CLOCK
730 endif #HYPERVISOR_GUEST
735 source "arch/x86/Kconfig.cpu"
739 prompt "HPET Timer Support" if X86_32
741 Use the IA-PC HPET (High Precision Event Timer) to manage
742 time in preference to the PIT and RTC, if a HPET is
744 HPET is the next generation timer replacing legacy 8254s.
745 The HPET provides a stable time base on SMP
746 systems, unlike the TSC, but it is more expensive to access,
747 as it is off-chip. You can find the HPET spec at
748 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
750 You can safely choose Y here. However, HPET will only be
751 activated if the platform and the BIOS support this feature.
752 Otherwise the 8254 will be used for timing services.
754 Choose N to continue using the legacy 8254 timer.
756 config HPET_EMULATE_RTC
758 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
761 def_bool y if X86_INTEL_MID
762 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
764 depends on X86_INTEL_MID && SFI
766 APB timer is the replacement for 8254, HPET on X86 MID platforms.
767 The APBT provides a stable time base on SMP
768 systems, unlike the TSC, but it is more expensive to access,
769 as it is off-chip. APB timers are always running regardless of CPU
770 C states, they are used as per CPU clockevent device when possible.
772 # Mark as expert because too many people got it wrong.
773 # The code disables itself when not needed.
776 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
777 bool "Enable DMI scanning" if EXPERT
779 Enabled scanning of DMI to identify machine quirks. Say Y
780 here unless you have verified that your setup is not
781 affected by entries in the DMI blacklist. Required by PNP
785 bool "Old AMD GART IOMMU support"
787 depends on X86_64 && PCI && AMD_NB
789 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
790 GART based hardware IOMMUs.
792 The GART supports full DMA access for devices with 32-bit access
793 limitations, on systems with more than 3 GB. This is usually needed
794 for USB, sound, many IDE/SATA chipsets and some other devices.
796 Newer systems typically have a modern AMD IOMMU, supported via
797 the CONFIG_AMD_IOMMU=y config option.
799 In normal configurations this driver is only active when needed:
800 there's more than 3 GB of memory and the system contains a
801 32-bit limited device.
806 bool "IBM Calgary IOMMU support"
808 depends on X86_64 && PCI
810 Support for hardware IOMMUs in IBM's xSeries x366 and x460
811 systems. Needed to run systems with more than 3GB of memory
812 properly with 32-bit PCI devices that do not support DAC
813 (Double Address Cycle). Calgary also supports bus level
814 isolation, where all DMAs pass through the IOMMU. This
815 prevents them from going anywhere except their intended
816 destination. This catches hard-to-find kernel bugs and
817 mis-behaving drivers and devices that do not use the DMA-API
818 properly to set up their DMA buffers. The IOMMU can be
819 turned off at boot time with the iommu=off parameter.
820 Normally the kernel will make the right choice by itself.
823 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
825 prompt "Should Calgary be enabled by default?"
826 depends on CALGARY_IOMMU
828 Should Calgary be enabled by default? if you choose 'y', Calgary
829 will be used (if it exists). If you choose 'n', Calgary will not be
830 used even if it exists. If you choose 'n' and would like to use
831 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
834 # need this always selected by IOMMU for the VIA workaround
838 Support for software bounce buffers used on x86-64 systems
839 which don't have a hardware IOMMU. Using this PCI devices
840 which can only access 32-bits of memory can be used on systems
841 with more than 3 GB of memory.
846 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
849 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
850 depends on X86_64 && SMP && DEBUG_KERNEL
851 select CPUMASK_OFFSTACK
853 Enable maximum number of CPUS and NUMA Nodes for this architecture.
857 int "Maximum number of CPUs" if SMP && !MAXSMP
858 range 2 8 if SMP && X86_32 && !X86_BIGSMP
859 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
860 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
862 default "8192" if MAXSMP
863 default "32" if SMP && X86_BIGSMP
864 default "8" if SMP && X86_32
867 This allows you to specify the maximum number of CPUs which this
868 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
869 supported value is 8192, otherwise the maximum value is 512. The
870 minimum value which makes sense is 2.
872 This is purely to save memory - each supported CPU adds
873 approximately eight kilobytes to the kernel image.
876 bool "SMT (Hyperthreading) scheduler support"
879 SMT scheduler support improves the CPU scheduler's decision making
880 when dealing with Intel Pentium 4 chips with HyperThreading at a
881 cost of slightly increased overhead in some places. If unsure say
886 prompt "Multi-core scheduler support"
889 Multi-core scheduler support improves the CPU scheduler's decision
890 making when dealing with multi-core CPU chips at a cost of slightly
891 increased overhead in some places. If unsure say N here.
893 source "kernel/Kconfig.preempt"
897 depends on !SMP && X86_LOCAL_APIC
900 bool "Local APIC support on uniprocessors" if !PCI_MSI
902 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
904 A local APIC (Advanced Programmable Interrupt Controller) is an
905 integrated interrupt controller in the CPU. If you have a single-CPU
906 system which has a processor with a local APIC, you can say Y here to
907 enable and use it. If you say Y here even though your machine doesn't
908 have a local APIC, then the kernel will still run with no slowdown at
909 all. The local APIC supports CPU-generated self-interrupts (timer,
910 performance counters), and the NMI watchdog which detects hard
914 bool "IO-APIC support on uniprocessors"
915 depends on X86_UP_APIC
917 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
918 SMP-capable replacement for PC-style interrupt controllers. Most
919 SMP systems and many recent uniprocessor systems have one.
921 If you have a single-CPU system with an IO-APIC, you can say Y here
922 to use it. If you say Y here even though your machine doesn't have
923 an IO-APIC, then the kernel will still run with no slowdown at all.
925 config X86_LOCAL_APIC
927 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
928 select IRQ_DOMAIN_HIERARCHY
929 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
933 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
935 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
936 bool "Reroute for broken boot IRQs"
937 depends on X86_IO_APIC
939 This option enables a workaround that fixes a source of
940 spurious interrupts. This is recommended when threaded
941 interrupt handling is used on systems where the generation of
942 superfluous "boot interrupts" cannot be disabled.
944 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
945 entry in the chipset's IO-APIC is masked (as, e.g. the RT
946 kernel does during interrupt handling). On chipsets where this
947 boot IRQ generation cannot be disabled, this workaround keeps
948 the original IRQ line masked so that only the equivalent "boot
949 IRQ" is delivered to the CPUs. The workaround also tells the
950 kernel to set up the IRQ handler on the boot IRQ line. In this
951 way only one interrupt is delivered to the kernel. Otherwise
952 the spurious second interrupt may cause the kernel to bring
953 down (vital) interrupt lines.
955 Only affects "broken" chipsets. Interrupt sharing may be
956 increased on these systems.
959 bool "Machine Check / overheating reporting"
960 select GENERIC_ALLOCATOR
963 Machine Check support allows the processor to notify the
964 kernel if it detects a problem (e.g. overheating, data corruption).
965 The action the kernel takes depends on the severity of the problem,
966 ranging from warning messages to halting the machine.
970 prompt "Intel MCE features"
971 depends on X86_MCE && X86_LOCAL_APIC
973 Additional support for intel specific MCE features such as
978 prompt "AMD MCE features"
979 depends on X86_MCE && X86_LOCAL_APIC
981 Additional support for AMD specific MCE features such as
982 the DRAM Error Threshold.
984 config X86_ANCIENT_MCE
985 bool "Support for old Pentium 5 / WinChip machine checks"
986 depends on X86_32 && X86_MCE
988 Include support for machine check handling on old Pentium 5 or WinChip
989 systems. These typically need to be enabled explicitly on the command
992 config X86_MCE_THRESHOLD
993 depends on X86_MCE_AMD || X86_MCE_INTEL
996 config X86_MCE_INJECT
998 tristate "Machine check injector support"
1000 Provide support for injecting machine checks for testing purposes.
1001 If you don't know what a machine check is and you don't do kernel
1002 QA it is safe to say n.
1004 config X86_THERMAL_VECTOR
1006 depends on X86_MCE_INTEL
1008 config X86_LEGACY_VM86
1009 bool "Legacy VM86 support"
1013 This option allows user programs to put the CPU into V8086
1014 mode, which is an 80286-era approximation of 16-bit real mode.
1016 Some very old versions of X and/or vbetool require this option
1017 for user mode setting. Similarly, DOSEMU will use it if
1018 available to accelerate real mode DOS programs. However, any
1019 recent version of DOSEMU, X, or vbetool should be fully
1020 functional even without kernel VM86 support, as they will all
1021 fall back to software emulation. Nevertheless, if you are using
1022 a 16-bit DOS program where 16-bit performance matters, vm86
1023 mode might be faster than emulation and you might want to
1026 Note that any app that works on a 64-bit kernel is unlikely to
1027 need this option, as 64-bit kernels don't, and can't, support
1028 V8086 mode. This option is also unrelated to 16-bit protected
1029 mode and is not needed to run most 16-bit programs under Wine.
1031 Enabling this option increases the complexity of the kernel
1032 and slows down exception handling a tiny bit.
1034 If unsure, say N here.
1038 default X86_LEGACY_VM86
1041 bool "Enable support for 16-bit segments" if EXPERT
1043 depends on MODIFY_LDT_SYSCALL
1045 This option is required by programs like Wine to run 16-bit
1046 protected mode legacy code on x86 processors. Disabling
1047 this option saves about 300 bytes on i386, or around 6K text
1048 plus 16K runtime memory on x86-64,
1052 depends on X86_16BIT && X86_32
1056 depends on X86_16BIT && X86_64
1058 config X86_VSYSCALL_EMULATION
1059 bool "Enable vsyscall emulation" if EXPERT
1063 This enables emulation of the legacy vsyscall page. Disabling
1064 it is roughly equivalent to booting with vsyscall=none, except
1065 that it will also disable the helpful warning if a program
1066 tries to use a vsyscall. With this option set to N, offending
1067 programs will just segfault, citing addresses of the form
1070 This option is required by many programs built before 2013, and
1071 care should be used even with newer programs if set to N.
1073 Disabling this option saves about 7K of kernel size and
1074 possibly 4K of additional runtime pagetable memory.
1077 tristate "Toshiba Laptop support"
1080 This adds a driver to safely access the System Management Mode of
1081 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1082 not work on models with a Phoenix BIOS. The System Management Mode
1083 is used to set the BIOS and power saving options on Toshiba portables.
1085 For information on utilities to make use of this driver see the
1086 Toshiba Linux utilities web site at:
1087 <http://www.buzzard.org.uk/toshiba/>.
1089 Say Y if you intend to run this kernel on a Toshiba portable.
1093 tristate "Dell i8k legacy laptop support"
1095 select SENSORS_DELL_SMM
1097 This option enables legacy /proc/i8k userspace interface in hwmon
1098 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1099 temperature and allows controlling fan speeds of Dell laptops via
1100 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1101 it reports also power and hotkey status. For fan speed control is
1102 needed userspace package i8kutils.
1104 Say Y if you intend to run this kernel on old Dell laptops or want to
1105 use userspace package i8kutils.
1108 config X86_REBOOTFIXUPS
1109 bool "Enable X86 board specific fixups for reboot"
1112 This enables chipset and/or board specific fixups to be done
1113 in order to get reboot to work correctly. This is only needed on
1114 some combinations of hardware and BIOS. The symptom, for which
1115 this config is intended, is when reboot ends with a stalled/hung
1118 Currently, the only fixup is for the Geode machines using
1119 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1121 Say Y if you want to enable the fixup. Currently, it's safe to
1122 enable this option even if you don't need it.
1126 bool "CPU microcode loading support"
1128 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1129 depends on BLK_DEV_INITRD
1133 If you say Y here, you will be able to update the microcode on
1134 certain Intel and AMD processors. The Intel support is for the
1135 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1136 Xeon etc. The AMD support is for families 0x10 and later. You will
1137 obviously need the actual microcode binary data itself which is not
1138 shipped with the Linux kernel.
1140 This option selects the general module only, you need to select
1141 at least one vendor specific module as well.
1143 To compile this driver as a module, choose M here: the module
1144 will be called microcode.
1146 config MICROCODE_INTEL
1147 bool "Intel microcode loading support"
1148 depends on MICROCODE
1152 This options enables microcode patch loading support for Intel
1155 For the current Intel microcode data package go to
1156 <https://downloadcenter.intel.com> and search for
1157 'Linux Processor Microcode Data File'.
1159 config MICROCODE_AMD
1160 bool "AMD microcode loading support"
1161 depends on MICROCODE
1164 If you select this option, microcode patch loading support for AMD
1165 processors will be enabled.
1167 config MICROCODE_OLD_INTERFACE
1169 depends on MICROCODE
1172 tristate "/dev/cpu/*/msr - Model-specific register support"
1174 This device gives privileged processes access to the x86
1175 Model-Specific Registers (MSRs). It is a character device with
1176 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1177 MSR accesses are directed to a specific CPU on multi-processor
1181 tristate "/dev/cpu/*/cpuid - CPU information support"
1183 This device gives processes access to the x86 CPUID instruction to
1184 be executed on a specific processor. It is a character device
1185 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1189 prompt "High Memory Support"
1196 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1197 However, the address space of 32-bit x86 processors is only 4
1198 Gigabytes large. That means that, if you have a large amount of
1199 physical memory, not all of it can be "permanently mapped" by the
1200 kernel. The physical memory that's not permanently mapped is called
1203 If you are compiling a kernel which will never run on a machine with
1204 more than 1 Gigabyte total physical RAM, answer "off" here (default
1205 choice and suitable for most users). This will result in a "3GB/1GB"
1206 split: 3GB are mapped so that each process sees a 3GB virtual memory
1207 space and the remaining part of the 4GB virtual memory space is used
1208 by the kernel to permanently map as much physical memory as
1211 If the machine has between 1 and 4 Gigabytes physical RAM, then
1214 If more than 4 Gigabytes is used then answer "64GB" here. This
1215 selection turns Intel PAE (Physical Address Extension) mode on.
1216 PAE implements 3-level paging on IA32 processors. PAE is fully
1217 supported by Linux, PAE mode is implemented on all recent Intel
1218 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1219 then the kernel will not boot on CPUs that don't support PAE!
1221 The actual amount of total physical memory will either be
1222 auto detected or can be forced by using a kernel command line option
1223 such as "mem=256M". (Try "man bootparam" or see the documentation of
1224 your boot loader (lilo or loadlin) about how to pass options to the
1225 kernel at boot time.)
1227 If unsure, say "off".
1232 Select this if you have a 32-bit processor and between 1 and 4
1233 gigabytes of physical RAM.
1240 Select this if you have a 32-bit processor and more than 4
1241 gigabytes of physical RAM.
1246 prompt "Memory split" if EXPERT
1250 Select the desired split between kernel and user memory.
1252 If the address range available to the kernel is less than the
1253 physical memory installed, the remaining memory will be available
1254 as "high memory". Accessing high memory is a little more costly
1255 than low memory, as it needs to be mapped into the kernel first.
1256 Note that increasing the kernel address space limits the range
1257 available to user programs, making the address space there
1258 tighter. Selecting anything other than the default 3G/1G split
1259 will also likely make your kernel incompatible with binary-only
1262 If you are not absolutely sure what you are doing, leave this
1266 bool "3G/1G user/kernel split"
1267 config VMSPLIT_3G_OPT
1269 bool "3G/1G user/kernel split (for full 1G low memory)"
1271 bool "2G/2G user/kernel split"
1272 config VMSPLIT_2G_OPT
1274 bool "2G/2G user/kernel split (for full 2G low memory)"
1276 bool "1G/3G user/kernel split"
1281 default 0xB0000000 if VMSPLIT_3G_OPT
1282 default 0x80000000 if VMSPLIT_2G
1283 default 0x78000000 if VMSPLIT_2G_OPT
1284 default 0x40000000 if VMSPLIT_1G
1290 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1293 bool "PAE (Physical Address Extension) Support"
1294 depends on X86_32 && !HIGHMEM4G
1297 PAE is required for NX support, and furthermore enables
1298 larger swapspace support for non-overcommit purposes. It
1299 has the cost of more pagetable lookup overhead, and also
1300 consumes more pagetable space per process.
1302 config ARCH_PHYS_ADDR_T_64BIT
1304 depends on X86_64 || X86_PAE
1306 config ARCH_DMA_ADDR_T_64BIT
1308 depends on X86_64 || HIGHMEM64G
1310 config X86_DIRECT_GBPAGES
1312 depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1314 Certain kernel features effectively disable kernel
1315 linear 1 GB mappings (even if the CPU otherwise
1316 supports them), so don't confuse the user by printing
1317 that we have them enabled.
1319 # Common NUMA Features
1321 bool "Numa Memory Allocation and Scheduler Support"
1323 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1324 default y if X86_BIGSMP
1326 Enable NUMA (Non Uniform Memory Access) support.
1328 The kernel will try to allocate memory used by a CPU on the
1329 local memory controller of the CPU and add some more
1330 NUMA awareness to the kernel.
1332 For 64-bit this is recommended if the system is Intel Core i7
1333 (or later), AMD Opteron, or EM64T NUMA.
1335 For 32-bit this is only needed if you boot a 32-bit
1336 kernel on a 64-bit NUMA platform.
1338 Otherwise, you should say N.
1342 prompt "Old style AMD Opteron NUMA detection"
1343 depends on X86_64 && NUMA && PCI
1345 Enable AMD NUMA node topology detection. You should say Y here if
1346 you have a multi processor AMD system. This uses an old method to
1347 read the NUMA configuration directly from the builtin Northbridge
1348 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1349 which also takes priority if both are compiled in.
1351 config X86_64_ACPI_NUMA
1353 prompt "ACPI NUMA detection"
1354 depends on X86_64 && NUMA && ACPI && PCI
1357 Enable ACPI SRAT based node topology detection.
1359 # Some NUMA nodes have memory ranges that span
1360 # other nodes. Even though a pfn is valid and
1361 # between a node's start and end pfns, it may not
1362 # reside on that node. See memmap_init_zone()
1364 config NODES_SPAN_OTHER_NODES
1366 depends on X86_64_ACPI_NUMA
1369 bool "NUMA emulation"
1372 Enable NUMA emulation. A flat machine will be split
1373 into virtual nodes when booted with "numa=fake=N", where N is the
1374 number of nodes. This is only useful for debugging.
1377 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1379 default "10" if MAXSMP
1380 default "6" if X86_64
1382 depends on NEED_MULTIPLE_NODES
1384 Specify the maximum number of NUMA Nodes available on the target
1385 system. Increases memory reserved to accommodate various tables.
1387 config ARCH_HAVE_MEMORY_PRESENT
1389 depends on X86_32 && DISCONTIGMEM
1391 config NEED_NODE_MEMMAP_SIZE
1393 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1395 config ARCH_FLATMEM_ENABLE
1397 depends on X86_32 && !NUMA
1399 config ARCH_DISCONTIGMEM_ENABLE
1401 depends on NUMA && X86_32
1403 config ARCH_DISCONTIGMEM_DEFAULT
1405 depends on NUMA && X86_32
1407 config ARCH_SPARSEMEM_ENABLE
1409 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1410 select SPARSEMEM_STATIC if X86_32
1411 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1413 config ARCH_SPARSEMEM_DEFAULT
1417 config ARCH_SELECT_MEMORY_MODEL
1419 depends on ARCH_SPARSEMEM_ENABLE
1421 config ARCH_MEMORY_PROBE
1422 bool "Enable sysfs memory/probe interface"
1423 depends on X86_64 && MEMORY_HOTPLUG
1425 This option enables a sysfs memory/probe interface for testing.
1426 See Documentation/memory-hotplug.txt for more information.
1427 If you are unsure how to answer this question, answer N.
1429 config ARCH_PROC_KCORE_TEXT
1431 depends on X86_64 && PROC_KCORE
1433 config ILLEGAL_POINTER_VALUE
1436 default 0xdead000000000000 if X86_64
1440 config X86_PMEM_LEGACY_DEVICE
1443 config X86_PMEM_LEGACY
1444 tristate "Support non-standard NVDIMMs and ADR protected memory"
1445 depends on PHYS_ADDR_T_64BIT
1447 select X86_PMEM_LEGACY_DEVICE
1450 Treat memory marked using the non-standard e820 type of 12 as used
1451 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1452 The kernel will offer these regions to the 'pmem' driver so
1453 they can be used for persistent storage.
1458 bool "Allocate 3rd-level pagetables from highmem"
1461 The VM uses one page table entry for each page of physical memory.
1462 For systems with a lot of RAM, this can be wasteful of precious
1463 low memory. Setting this option will put user-space page table
1464 entries in high memory.
1466 config X86_CHECK_BIOS_CORRUPTION
1467 bool "Check for low memory corruption"
1469 Periodically check for memory corruption in low memory, which
1470 is suspected to be caused by BIOS. Even when enabled in the
1471 configuration, it is disabled at runtime. Enable it by
1472 setting "memory_corruption_check=1" on the kernel command
1473 line. By default it scans the low 64k of memory every 60
1474 seconds; see the memory_corruption_check_size and
1475 memory_corruption_check_period parameters in
1476 Documentation/kernel-parameters.txt to adjust this.
1478 When enabled with the default parameters, this option has
1479 almost no overhead, as it reserves a relatively small amount
1480 of memory and scans it infrequently. It both detects corruption
1481 and prevents it from affecting the running system.
1483 It is, however, intended as a diagnostic tool; if repeatable
1484 BIOS-originated corruption always affects the same memory,
1485 you can use memmap= to prevent the kernel from using that
1488 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1489 bool "Set the default setting of memory_corruption_check"
1490 depends on X86_CHECK_BIOS_CORRUPTION
1493 Set whether the default state of memory_corruption_check is
1496 config X86_RESERVE_LOW
1497 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1501 Specify the amount of low memory to reserve for the BIOS.
1503 The first page contains BIOS data structures that the kernel
1504 must not use, so that page must always be reserved.
1506 By default we reserve the first 64K of physical RAM, as a
1507 number of BIOSes are known to corrupt that memory range
1508 during events such as suspend/resume or monitor cable
1509 insertion, so it must not be used by the kernel.
1511 You can set this to 4 if you are absolutely sure that you
1512 trust the BIOS to get all its memory reservations and usages
1513 right. If you know your BIOS have problems beyond the
1514 default 64K area, you can set this to 640 to avoid using the
1515 entire low memory range.
1517 If you have doubts about the BIOS (e.g. suspend/resume does
1518 not work or there's kernel crashes after certain hardware
1519 hotplug events) then you might want to enable
1520 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1521 typical corruption patterns.
1523 Leave this to the default value of 64 if you are unsure.
1525 config MATH_EMULATION
1527 depends on MODIFY_LDT_SYSCALL
1528 prompt "Math emulation" if X86_32
1530 Linux can emulate a math coprocessor (used for floating point
1531 operations) if you don't have one. 486DX and Pentium processors have
1532 a math coprocessor built in, 486SX and 386 do not, unless you added
1533 a 487DX or 387, respectively. (The messages during boot time can
1534 give you some hints here ["man dmesg"].) Everyone needs either a
1535 coprocessor or this emulation.
1537 If you don't have a math coprocessor, you need to say Y here; if you
1538 say Y here even though you have a coprocessor, the coprocessor will
1539 be used nevertheless. (This behavior can be changed with the kernel
1540 command line option "no387", which comes handy if your coprocessor
1541 is broken. Try "man bootparam" or see the documentation of your boot
1542 loader (lilo or loadlin) about how to pass options to the kernel at
1543 boot time.) This means that it is a good idea to say Y here if you
1544 intend to use this kernel on different machines.
1546 More information about the internals of the Linux math coprocessor
1547 emulation can be found in <file:arch/x86/math-emu/README>.
1549 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1550 kernel, it won't hurt.
1554 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1556 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1557 the Memory Type Range Registers (MTRRs) may be used to control
1558 processor access to memory ranges. This is most useful if you have
1559 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1560 allows bus write transfers to be combined into a larger transfer
1561 before bursting over the PCI/AGP bus. This can increase performance
1562 of image write operations 2.5 times or more. Saying Y here creates a
1563 /proc/mtrr file which may be used to manipulate your processor's
1564 MTRRs. Typically the X server should use this.
1566 This code has a reasonably generic interface so that similar
1567 control registers on other processors can be easily supported
1570 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1571 Registers (ARRs) which provide a similar functionality to MTRRs. For
1572 these, the ARRs are used to emulate the MTRRs.
1573 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1574 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1575 write-combining. All of these processors are supported by this code
1576 and it makes sense to say Y here if you have one of them.
1578 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1579 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1580 can lead to all sorts of problems, so it's good to say Y here.
1582 You can safely say Y even if your machine doesn't have MTRRs, you'll
1583 just add about 9 KB to your kernel.
1585 See <file:Documentation/x86/mtrr.txt> for more information.
1587 config MTRR_SANITIZER
1589 prompt "MTRR cleanup support"
1592 Convert MTRR layout from continuous to discrete, so X drivers can
1593 add writeback entries.
1595 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1596 The largest mtrr entry size for a continuous block can be set with
1601 config MTRR_SANITIZER_ENABLE_DEFAULT
1602 int "MTRR cleanup enable value (0-1)"
1605 depends on MTRR_SANITIZER
1607 Enable mtrr cleanup default value
1609 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1610 int "MTRR cleanup spare reg num (0-7)"
1613 depends on MTRR_SANITIZER
1615 mtrr cleanup spare entries default, it can be changed via
1616 mtrr_spare_reg_nr=N on the kernel command line.
1620 prompt "x86 PAT support" if EXPERT
1623 Use PAT attributes to setup page level cache control.
1625 PATs are the modern equivalents of MTRRs and are much more
1626 flexible than MTRRs.
1628 Say N here if you see bootup problems (boot crash, boot hang,
1629 spontaneous reboots) or a non-working video driver.
1633 config ARCH_USES_PG_UNCACHED
1639 prompt "x86 architectural random number generator" if EXPERT
1641 Enable the x86 architectural RDRAND instruction
1642 (Intel Bull Mountain technology) to generate random numbers.
1643 If supported, this is a high bandwidth, cryptographically
1644 secure hardware random number generator.
1648 prompt "Supervisor Mode Access Prevention" if EXPERT
1650 Supervisor Mode Access Prevention (SMAP) is a security
1651 feature in newer Intel processors. There is a small
1652 performance cost if this enabled and turned on; there is
1653 also a small increase in the kernel size if this is enabled.
1657 config X86_INTEL_MPX
1658 prompt "Intel MPX (Memory Protection Extensions)"
1660 depends on CPU_SUP_INTEL
1662 MPX provides hardware features that can be used in
1663 conjunction with compiler-instrumented code to check
1664 memory references. It is designed to detect buffer
1665 overflow or underflow bugs.
1667 This option enables running applications which are
1668 instrumented or otherwise use MPX. It does not use MPX
1669 itself inside the kernel or to protect the kernel
1670 against bad memory references.
1672 Enabling this option will make the kernel larger:
1673 ~8k of kernel text and 36 bytes of data on a 64-bit
1674 defconfig. It adds a long to the 'mm_struct' which
1675 will increase the kernel memory overhead of each
1676 process and adds some branches to paths used during
1677 exec() and munmap().
1679 For details, see Documentation/x86/intel_mpx.txt
1684 bool "EFI runtime service support"
1687 select EFI_RUNTIME_WRAPPERS
1689 This enables the kernel to use EFI runtime services that are
1690 available (such as the EFI variable services).
1692 This option is only useful on systems that have EFI firmware.
1693 In addition, you should use the latest ELILO loader available
1694 at <http://elilo.sourceforge.net> in order to take advantage
1695 of EFI runtime services. However, even with this option, the
1696 resultant kernel should continue to boot on existing non-EFI
1700 bool "EFI stub support"
1701 depends on EFI && !X86_USE_3DNOW
1704 This kernel feature allows a bzImage to be loaded directly
1705 by EFI firmware without the use of a bootloader.
1707 See Documentation/efi-stub.txt for more information.
1710 bool "EFI mixed-mode support"
1711 depends on EFI_STUB && X86_64
1713 Enabling this feature allows a 64-bit kernel to be booted
1714 on a 32-bit firmware, provided that your CPU supports 64-bit
1717 Note that it is not possible to boot a mixed-mode enabled
1718 kernel via the EFI boot stub - a bootloader that supports
1719 the EFI handover protocol must be used.
1725 prompt "Enable seccomp to safely compute untrusted bytecode"
1727 This kernel feature is useful for number crunching applications
1728 that may need to compute untrusted bytecode during their
1729 execution. By using pipes or other transports made available to
1730 the process as file descriptors supporting the read/write
1731 syscalls, it's possible to isolate those applications in
1732 their own address space using seccomp. Once seccomp is
1733 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1734 and the task is only allowed to execute a few safe syscalls
1735 defined by each seccomp mode.
1737 If unsure, say Y. Only embedded should say N here.
1739 source kernel/Kconfig.hz
1742 bool "kexec system call"
1745 kexec is a system call that implements the ability to shutdown your
1746 current kernel, and to start another kernel. It is like a reboot
1747 but it is independent of the system firmware. And like a reboot
1748 you can start any kernel with it, not just Linux.
1750 The name comes from the similarity to the exec system call.
1752 It is an ongoing process to be certain the hardware in a machine
1753 is properly shutdown, so do not be surprised if this code does not
1754 initially work for you. As of this writing the exact hardware
1755 interface is strongly in flux, so no good recommendation can be
1759 bool "kexec file based system call"
1764 depends on CRYPTO_SHA256=y
1766 This is new version of kexec system call. This system call is
1767 file based and takes file descriptors as system call argument
1768 for kernel and initramfs as opposed to list of segments as
1769 accepted by previous system call.
1771 config KEXEC_VERIFY_SIG
1772 bool "Verify kernel signature during kexec_file_load() syscall"
1773 depends on KEXEC_FILE
1775 This option makes kernel signature verification mandatory for
1776 the kexec_file_load() syscall.
1778 In addition to that option, you need to enable signature
1779 verification for the corresponding kernel image type being
1780 loaded in order for this to work.
1782 config KEXEC_BZIMAGE_VERIFY_SIG
1783 bool "Enable bzImage signature verification support"
1784 depends on KEXEC_VERIFY_SIG
1785 depends on SIGNED_PE_FILE_VERIFICATION
1786 select SYSTEM_TRUSTED_KEYRING
1788 Enable bzImage signature verification support.
1791 bool "kernel crash dumps"
1792 depends on X86_64 || (X86_32 && HIGHMEM)
1794 Generate crash dump after being started by kexec.
1795 This should be normally only set in special crash dump kernels
1796 which are loaded in the main kernel with kexec-tools into
1797 a specially reserved region and then later executed after
1798 a crash by kdump/kexec. The crash dump kernel must be compiled
1799 to a memory address not used by the main kernel or BIOS using
1800 PHYSICAL_START, or it must be built as a relocatable image
1801 (CONFIG_RELOCATABLE=y).
1802 For more details see Documentation/kdump/kdump.txt
1806 depends on KEXEC && HIBERNATION
1808 Jump between original kernel and kexeced kernel and invoke
1809 code in physical address mode via KEXEC
1811 config PHYSICAL_START
1812 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1815 This gives the physical address where the kernel is loaded.
1817 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1818 bzImage will decompress itself to above physical address and
1819 run from there. Otherwise, bzImage will run from the address where
1820 it has been loaded by the boot loader and will ignore above physical
1823 In normal kdump cases one does not have to set/change this option
1824 as now bzImage can be compiled as a completely relocatable image
1825 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1826 address. This option is mainly useful for the folks who don't want
1827 to use a bzImage for capturing the crash dump and want to use a
1828 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1829 to be specifically compiled to run from a specific memory area
1830 (normally a reserved region) and this option comes handy.
1832 So if you are using bzImage for capturing the crash dump,
1833 leave the value here unchanged to 0x1000000 and set
1834 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1835 for capturing the crash dump change this value to start of
1836 the reserved region. In other words, it can be set based on
1837 the "X" value as specified in the "crashkernel=YM@XM"
1838 command line boot parameter passed to the panic-ed
1839 kernel. Please take a look at Documentation/kdump/kdump.txt
1840 for more details about crash dumps.
1842 Usage of bzImage for capturing the crash dump is recommended as
1843 one does not have to build two kernels. Same kernel can be used
1844 as production kernel and capture kernel. Above option should have
1845 gone away after relocatable bzImage support is introduced. But it
1846 is present because there are users out there who continue to use
1847 vmlinux for dump capture. This option should go away down the
1850 Don't change this unless you know what you are doing.
1853 bool "Build a relocatable kernel"
1856 This builds a kernel image that retains relocation information
1857 so it can be loaded someplace besides the default 1MB.
1858 The relocations tend to make the kernel binary about 10% larger,
1859 but are discarded at runtime.
1861 One use is for the kexec on panic case where the recovery kernel
1862 must live at a different physical address than the primary
1865 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1866 it has been loaded at and the compile time physical address
1867 (CONFIG_PHYSICAL_START) is used as the minimum location.
1869 config RANDOMIZE_BASE
1870 bool "Randomize the address of the kernel image"
1871 depends on RELOCATABLE
1874 Randomizes the physical and virtual address at which the
1875 kernel image is decompressed, as a security feature that
1876 deters exploit attempts relying on knowledge of the location
1877 of kernel internals.
1879 Entropy is generated using the RDRAND instruction if it is
1880 supported. If RDTSC is supported, it is used as well. If
1881 neither RDRAND nor RDTSC are supported, then randomness is
1882 read from the i8254 timer.
1884 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1885 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1886 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1887 minimum of 2MiB, only 10 bits of entropy is theoretically
1888 possible. At best, due to page table layouts, 64-bit can use
1889 9 bits of entropy and 32-bit uses 8 bits.
1893 config RANDOMIZE_BASE_MAX_OFFSET
1894 hex "Maximum kASLR offset allowed" if EXPERT
1895 depends on RANDOMIZE_BASE
1896 range 0x0 0x20000000 if X86_32
1897 default "0x20000000" if X86_32
1898 range 0x0 0x40000000 if X86_64
1899 default "0x40000000" if X86_64
1901 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1902 memory is used to determine the maximal offset in bytes that will
1903 be applied to the kernel when kernel Address Space Layout
1904 Randomization (kASLR) is active. This must be a multiple of
1907 On 32-bit this is limited to 512MiB by page table layouts. The
1910 On 64-bit this is limited by how the kernel fixmap page table is
1911 positioned, so this cannot be larger than 1GiB currently. Without
1912 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1913 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1914 modules area will shrink to compensate, up to the current maximum
1915 1GiB to 1GiB split. The default is 1GiB.
1917 If unsure, leave at the default value.
1919 # Relocation on x86 needs some additional build support
1920 config X86_NEED_RELOCS
1922 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1924 config PHYSICAL_ALIGN
1925 hex "Alignment value to which kernel should be aligned"
1927 range 0x2000 0x1000000 if X86_32
1928 range 0x200000 0x1000000 if X86_64
1930 This value puts the alignment restrictions on physical address
1931 where kernel is loaded and run from. Kernel is compiled for an
1932 address which meets above alignment restriction.
1934 If bootloader loads the kernel at a non-aligned address and
1935 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1936 address aligned to above value and run from there.
1938 If bootloader loads the kernel at a non-aligned address and
1939 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1940 load address and decompress itself to the address it has been
1941 compiled for and run from there. The address for which kernel is
1942 compiled already meets above alignment restrictions. Hence the
1943 end result is that kernel runs from a physical address meeting
1944 above alignment restrictions.
1946 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1947 this value must be a multiple of 0x200000.
1949 Don't change this unless you know what you are doing.
1952 bool "Support for hot-pluggable CPUs"
1955 Say Y here to allow turning CPUs off and on. CPUs can be
1956 controlled through /sys/devices/system/cpu.
1957 ( Note: power management support will enable this option
1958 automatically on SMP systems. )
1959 Say N if you want to disable CPU hotplug.
1961 config BOOTPARAM_HOTPLUG_CPU0
1962 bool "Set default setting of cpu0_hotpluggable"
1964 depends on HOTPLUG_CPU
1966 Set whether default state of cpu0_hotpluggable is on or off.
1968 Say Y here to enable CPU0 hotplug by default. If this switch
1969 is turned on, there is no need to give cpu0_hotplug kernel
1970 parameter and the CPU0 hotplug feature is enabled by default.
1972 Please note: there are two known CPU0 dependencies if you want
1973 to enable the CPU0 hotplug feature either by this switch or by
1974 cpu0_hotplug kernel parameter.
1976 First, resume from hibernate or suspend always starts from CPU0.
1977 So hibernate and suspend are prevented if CPU0 is offline.
1979 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1980 offline if any interrupt can not migrate out of CPU0. There may
1981 be other CPU0 dependencies.
1983 Please make sure the dependencies are under your control before
1984 you enable this feature.
1986 Say N if you don't want to enable CPU0 hotplug feature by default.
1987 You still can enable the CPU0 hotplug feature at boot by kernel
1988 parameter cpu0_hotplug.
1990 config DEBUG_HOTPLUG_CPU0
1992 prompt "Debug CPU0 hotplug"
1993 depends on HOTPLUG_CPU
1995 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1996 soon as possible and boots up userspace with CPU0 offlined. User
1997 can online CPU0 back after boot time.
1999 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2000 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2001 compilation or giving cpu0_hotplug kernel parameter at boot.
2007 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2008 depends on X86_32 || IA32_EMULATION
2010 Certain buggy versions of glibc will crash if they are
2011 presented with a 32-bit vDSO that is not mapped at the address
2012 indicated in its segment table.
2014 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2015 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2016 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2017 the only released version with the bug, but OpenSUSE 9
2018 contains a buggy "glibc 2.3.2".
2020 The symptom of the bug is that everything crashes on startup, saying:
2021 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2023 Saying Y here changes the default value of the vdso32 boot
2024 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2025 This works around the glibc bug but hurts performance.
2027 If unsure, say N: if you are compiling your own kernel, you
2028 are unlikely to be using a buggy version of glibc.
2031 prompt "vsyscall table for legacy applications"
2033 default LEGACY_VSYSCALL_EMULATE
2035 Legacy user code that does not know how to find the vDSO expects
2036 to be able to issue three syscalls by calling fixed addresses in
2037 kernel space. Since this location is not randomized with ASLR,
2038 it can be used to assist security vulnerability exploitation.
2040 This setting can be changed at boot time via the kernel command
2041 line parameter vsyscall=[native|emulate|none].
2043 On a system with recent enough glibc (2.14 or newer) and no
2044 static binaries, you can say None without a performance penalty
2045 to improve security.
2047 If unsure, select "Emulate".
2049 config LEGACY_VSYSCALL_NATIVE
2052 Actual executable code is located in the fixed vsyscall
2053 address mapping, implementing time() efficiently. Since
2054 this makes the mapping executable, it can be used during
2055 security vulnerability exploitation (traditionally as
2056 ROP gadgets). This configuration is not recommended.
2058 config LEGACY_VSYSCALL_EMULATE
2061 The kernel traps and emulates calls into the fixed
2062 vsyscall address mapping. This makes the mapping
2063 non-executable, but it still contains known contents,
2064 which could be used in certain rare security vulnerability
2065 exploits. This configuration is recommended when userspace
2066 still uses the vsyscall area.
2068 config LEGACY_VSYSCALL_NONE
2071 There will be no vsyscall mapping at all. This will
2072 eliminate any risk of ASLR bypass due to the vsyscall
2073 fixed address mapping. Attempts to use the vsyscalls
2074 will be reported to dmesg, so that either old or
2075 malicious userspace programs can be identified.
2080 bool "Built-in kernel command line"
2082 Allow for specifying boot arguments to the kernel at
2083 build time. On some systems (e.g. embedded ones), it is
2084 necessary or convenient to provide some or all of the
2085 kernel boot arguments with the kernel itself (that is,
2086 to not rely on the boot loader to provide them.)
2088 To compile command line arguments into the kernel,
2089 set this option to 'Y', then fill in the
2090 boot arguments in CONFIG_CMDLINE.
2092 Systems with fully functional boot loaders (i.e. non-embedded)
2093 should leave this option set to 'N'.
2096 string "Built-in kernel command string"
2097 depends on CMDLINE_BOOL
2100 Enter arguments here that should be compiled into the kernel
2101 image and used at boot time. If the boot loader provides a
2102 command line at boot time, it is appended to this string to
2103 form the full kernel command line, when the system boots.
2105 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2106 change this behavior.
2108 In most cases, the command line (whether built-in or provided
2109 by the boot loader) should specify the device for the root
2112 config CMDLINE_OVERRIDE
2113 bool "Built-in command line overrides boot loader arguments"
2114 depends on CMDLINE_BOOL
2116 Set this option to 'Y' to have the kernel ignore the boot loader
2117 command line, and use ONLY the built-in command line.
2119 This is used to work around broken boot loaders. This should
2120 be set to 'N' under normal conditions.
2122 config MODIFY_LDT_SYSCALL
2123 bool "Enable the LDT (local descriptor table)" if EXPERT
2126 Linux can allow user programs to install a per-process x86
2127 Local Descriptor Table (LDT) using the modify_ldt(2) system
2128 call. This is required to run 16-bit or segmented code such as
2129 DOSEMU or some Wine programs. It is also used by some very old
2130 threading libraries.
2132 Enabling this feature adds a small amount of overhead to
2133 context switches and increases the low-level kernel attack
2134 surface. Disabling it removes the modify_ldt(2) system call.
2136 Saying 'N' here may make sense for embedded or server kernels.
2138 source "kernel/livepatch/Kconfig"
2142 config ARCH_ENABLE_MEMORY_HOTPLUG
2144 depends on X86_64 || (X86_32 && HIGHMEM)
2146 config ARCH_ENABLE_MEMORY_HOTREMOVE
2148 depends on MEMORY_HOTPLUG
2150 config USE_PERCPU_NUMA_NODE_ID
2154 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2156 depends on X86_64 || X86_PAE
2158 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2160 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2162 menu "Power management and ACPI options"
2164 config ARCH_HIBERNATION_HEADER
2166 depends on X86_64 && HIBERNATION
2168 source "kernel/power/Kconfig"
2170 source "drivers/acpi/Kconfig"
2172 source "drivers/sfi/Kconfig"
2179 tristate "APM (Advanced Power Management) BIOS support"
2180 depends on X86_32 && PM_SLEEP
2182 APM is a BIOS specification for saving power using several different
2183 techniques. This is mostly useful for battery powered laptops with
2184 APM compliant BIOSes. If you say Y here, the system time will be
2185 reset after a RESUME operation, the /proc/apm device will provide
2186 battery status information, and user-space programs will receive
2187 notification of APM "events" (e.g. battery status change).
2189 If you select "Y" here, you can disable actual use of the APM
2190 BIOS by passing the "apm=off" option to the kernel at boot time.
2192 Note that the APM support is almost completely disabled for
2193 machines with more than one CPU.
2195 In order to use APM, you will need supporting software. For location
2196 and more information, read <file:Documentation/power/apm-acpi.txt>
2197 and the Battery Powered Linux mini-HOWTO, available from
2198 <http://www.tldp.org/docs.html#howto>.
2200 This driver does not spin down disk drives (see the hdparm(8)
2201 manpage ("man 8 hdparm") for that), and it doesn't turn off
2202 VESA-compliant "green" monitors.
2204 This driver does not support the TI 4000M TravelMate and the ACER
2205 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2206 desktop machines also don't have compliant BIOSes, and this driver
2207 may cause those machines to panic during the boot phase.
2209 Generally, if you don't have a battery in your machine, there isn't
2210 much point in using this driver and you should say N. If you get
2211 random kernel OOPSes or reboots that don't seem to be related to
2212 anything, try disabling/enabling this option (or disabling/enabling
2215 Some other things you should try when experiencing seemingly random,
2218 1) make sure that you have enough swap space and that it is
2220 2) pass the "no-hlt" option to the kernel
2221 3) switch on floating point emulation in the kernel and pass
2222 the "no387" option to the kernel
2223 4) pass the "floppy=nodma" option to the kernel
2224 5) pass the "mem=4M" option to the kernel (thereby disabling
2225 all but the first 4 MB of RAM)
2226 6) make sure that the CPU is not over clocked.
2227 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2228 8) disable the cache from your BIOS settings
2229 9) install a fan for the video card or exchange video RAM
2230 10) install a better fan for the CPU
2231 11) exchange RAM chips
2232 12) exchange the motherboard.
2234 To compile this driver as a module, choose M here: the
2235 module will be called apm.
2239 config APM_IGNORE_USER_SUSPEND
2240 bool "Ignore USER SUSPEND"
2242 This option will ignore USER SUSPEND requests. On machines with a
2243 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2244 series notebooks, it is necessary to say Y because of a BIOS bug.
2246 config APM_DO_ENABLE
2247 bool "Enable PM at boot time"
2249 Enable APM features at boot time. From page 36 of the APM BIOS
2250 specification: "When disabled, the APM BIOS does not automatically
2251 power manage devices, enter the Standby State, enter the Suspend
2252 State, or take power saving steps in response to CPU Idle calls."
2253 This driver will make CPU Idle calls when Linux is idle (unless this
2254 feature is turned off -- see "Do CPU IDLE calls", below). This
2255 should always save battery power, but more complicated APM features
2256 will be dependent on your BIOS implementation. You may need to turn
2257 this option off if your computer hangs at boot time when using APM
2258 support, or if it beeps continuously instead of suspending. Turn
2259 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2260 T400CDT. This is off by default since most machines do fine without
2265 bool "Make CPU Idle calls when idle"
2267 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2268 On some machines, this can activate improved power savings, such as
2269 a slowed CPU clock rate, when the machine is idle. These idle calls
2270 are made after the idle loop has run for some length of time (e.g.,
2271 333 mS). On some machines, this will cause a hang at boot time or
2272 whenever the CPU becomes idle. (On machines with more than one CPU,
2273 this option does nothing.)
2275 config APM_DISPLAY_BLANK
2276 bool "Enable console blanking using APM"
2278 Enable console blanking using the APM. Some laptops can use this to
2279 turn off the LCD backlight when the screen blanker of the Linux
2280 virtual console blanks the screen. Note that this is only used by
2281 the virtual console screen blanker, and won't turn off the backlight
2282 when using the X Window system. This also doesn't have anything to
2283 do with your VESA-compliant power-saving monitor. Further, this
2284 option doesn't work for all laptops -- it might not turn off your
2285 backlight at all, or it might print a lot of errors to the console,
2286 especially if you are using gpm.
2288 config APM_ALLOW_INTS
2289 bool "Allow interrupts during APM BIOS calls"
2291 Normally we disable external interrupts while we are making calls to
2292 the APM BIOS as a measure to lessen the effects of a badly behaving
2293 BIOS implementation. The BIOS should reenable interrupts if it
2294 needs to. Unfortunately, some BIOSes do not -- especially those in
2295 many of the newer IBM Thinkpads. If you experience hangs when you
2296 suspend, try setting this to Y. Otherwise, say N.
2300 source "drivers/cpufreq/Kconfig"
2302 source "drivers/cpuidle/Kconfig"
2304 source "drivers/idle/Kconfig"
2309 menu "Bus options (PCI etc.)"
2315 Find out whether you have a PCI motherboard. PCI is the name of a
2316 bus system, i.e. the way the CPU talks to the other stuff inside
2317 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2318 VESA. If you have PCI, say Y, otherwise N.
2321 prompt "PCI access mode"
2322 depends on X86_32 && PCI
2325 On PCI systems, the BIOS can be used to detect the PCI devices and
2326 determine their configuration. However, some old PCI motherboards
2327 have BIOS bugs and may crash if this is done. Also, some embedded
2328 PCI-based systems don't have any BIOS at all. Linux can also try to
2329 detect the PCI hardware directly without using the BIOS.
2331 With this option, you can specify how Linux should detect the
2332 PCI devices. If you choose "BIOS", the BIOS will be used,
2333 if you choose "Direct", the BIOS won't be used, and if you
2334 choose "MMConfig", then PCI Express MMCONFIG will be used.
2335 If you choose "Any", the kernel will try MMCONFIG, then the
2336 direct access method and falls back to the BIOS if that doesn't
2337 work. If unsure, go with the default, which is "Any".
2342 config PCI_GOMMCONFIG
2359 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2361 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2364 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2368 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2372 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2376 depends on PCI && XEN
2384 bool "Support mmconfig PCI config space access"
2385 depends on X86_64 && PCI && ACPI
2387 config PCI_CNB20LE_QUIRK
2388 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2391 Read the PCI windows out of the CNB20LE host bridge. This allows
2392 PCI hotplug to work on systems with the CNB20LE chipset which do
2395 There's no public spec for this chipset, and this functionality
2396 is known to be incomplete.
2398 You should say N unless you know you need this.
2400 source "drivers/pci/pcie/Kconfig"
2402 source "drivers/pci/Kconfig"
2404 # x86_64 have no ISA slots, but can have ISA-style DMA.
2406 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2409 Enables ISA-style DMA support for devices requiring such controllers.
2417 Find out whether you have ISA slots on your motherboard. ISA is the
2418 name of a bus system, i.e. the way the CPU talks to the other stuff
2419 inside your box. Other bus systems are PCI, EISA, MicroChannel
2420 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2421 newer boards don't support it. If you have ISA, say Y, otherwise N.
2427 The Extended Industry Standard Architecture (EISA) bus was
2428 developed as an open alternative to the IBM MicroChannel bus.
2430 The EISA bus provided some of the features of the IBM MicroChannel
2431 bus while maintaining backward compatibility with cards made for
2432 the older ISA bus. The EISA bus saw limited use between 1988 and
2433 1995 when it was made obsolete by the PCI bus.
2435 Say Y here if you are building a kernel for an EISA-based machine.
2439 source "drivers/eisa/Kconfig"
2442 tristate "NatSemi SCx200 support"
2444 This provides basic support for National Semiconductor's
2445 (now AMD's) Geode processors. The driver probes for the
2446 PCI-IDs of several on-chip devices, so its a good dependency
2447 for other scx200_* drivers.
2449 If compiled as a module, the driver is named scx200.
2451 config SCx200HR_TIMER
2452 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2456 This driver provides a clocksource built upon the on-chip
2457 27MHz high-resolution timer. Its also a workaround for
2458 NSC Geode SC-1100's buggy TSC, which loses time when the
2459 processor goes idle (as is done by the scheduler). The
2460 other workaround is idle=poll boot option.
2463 bool "One Laptop Per Child support"
2470 Add support for detecting the unique features of the OLPC
2474 bool "OLPC XO-1 Power Management"
2475 depends on OLPC && MFD_CS5535 && PM_SLEEP
2478 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2481 bool "OLPC XO-1 Real Time Clock"
2482 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2484 Add support for the XO-1 real time clock, which can be used as a
2485 programmable wakeup source.
2488 bool "OLPC XO-1 SCI extras"
2489 depends on OLPC && OLPC_XO1_PM
2495 Add support for SCI-based features of the OLPC XO-1 laptop:
2496 - EC-driven system wakeups
2500 - AC adapter status updates
2501 - Battery status updates
2503 config OLPC_XO15_SCI
2504 bool "OLPC XO-1.5 SCI extras"
2505 depends on OLPC && ACPI
2508 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2509 - EC-driven system wakeups
2510 - AC adapter status updates
2511 - Battery status updates
2514 bool "PCEngines ALIX System Support (LED setup)"
2517 This option enables system support for the PCEngines ALIX.
2518 At present this just sets up LEDs for GPIO control on
2519 ALIX2/3/6 boards. However, other system specific setup should
2522 Note: You must still enable the drivers for GPIO and LED support
2523 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2525 Note: You have to set alix.force=1 for boards with Award BIOS.
2528 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2531 This option enables system support for the Soekris Engineering net5501.
2534 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2538 This option enables system support for the Traverse Technologies GEOS.
2541 bool "Technologic Systems TS-5500 platform support"
2543 select CHECK_SIGNATURE
2547 This option enables system support for the Technologic Systems TS-5500.
2553 depends on CPU_SUP_AMD && PCI
2555 source "drivers/pcmcia/Kconfig"
2557 source "drivers/pci/hotplug/Kconfig"
2560 tristate "RapidIO support"
2564 If enabled this option will include drivers and the core
2565 infrastructure code to support RapidIO interconnect devices.
2567 source "drivers/rapidio/Kconfig"
2570 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2572 Firmwares often provide initial graphics framebuffers so the BIOS,
2573 bootloader or kernel can show basic video-output during boot for
2574 user-guidance and debugging. Historically, x86 used the VESA BIOS
2575 Extensions and EFI-framebuffers for this, which are mostly limited
2577 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2578 framebuffers so the new generic system-framebuffer drivers can be
2579 used on x86. If the framebuffer is not compatible with the generic
2580 modes, it is adverticed as fallback platform framebuffer so legacy
2581 drivers like efifb, vesafb and uvesafb can pick it up.
2582 If this option is not selected, all system framebuffers are always
2583 marked as fallback platform framebuffers as usual.
2585 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2586 not be able to pick up generic system framebuffers if this option
2587 is selected. You are highly encouraged to enable simplefb as
2588 replacement if you select this option. simplefb can correctly deal
2589 with generic system framebuffers. But you should still keep vesafb
2590 and others enabled as fallback if a system framebuffer is
2591 incompatible with simplefb.
2598 menu "Executable file formats / Emulations"
2600 source "fs/Kconfig.binfmt"
2602 config IA32_EMULATION
2603 bool "IA32 Emulation"
2606 select COMPAT_BINFMT_ELF
2607 select ARCH_WANT_OLD_COMPAT_IPC
2609 Include code to run legacy 32-bit programs under a
2610 64-bit kernel. You should likely turn this on, unless you're
2611 100% sure that you don't have any 32-bit programs left.
2614 tristate "IA32 a.out support"
2615 depends on IA32_EMULATION
2617 Support old a.out binaries in the 32bit emulation.
2620 bool "x32 ABI for 64-bit mode"
2623 Include code to run binaries for the x32 native 32-bit ABI
2624 for 64-bit processors. An x32 process gets access to the
2625 full 64-bit register file and wide data path while leaving
2626 pointers at 32 bits for smaller memory footprint.
2628 You will need a recent binutils (2.22 or later) with
2629 elf32_x86_64 support enabled to compile a kernel with this
2634 depends on IA32_EMULATION || X86_X32
2637 config COMPAT_FOR_U64_ALIGNMENT
2640 config SYSVIPC_COMPAT
2652 config HAVE_ATOMIC_IOMAP
2656 config X86_DEV_DMA_OPS
2658 depends on X86_64 || STA2X11
2660 config X86_DMA_REMAP
2668 source "net/Kconfig"
2670 source "drivers/Kconfig"
2672 source "drivers/firmware/Kconfig"
2676 source "arch/x86/Kconfig.debug"
2678 source "security/Kconfig"
2680 source "crypto/Kconfig"
2682 source "arch/x86/kvm/Kconfig"
2684 source "lib/Kconfig"
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