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 HAVE_ARCH_MMAP_RND_BITS if MMU
50 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
51 select ARCH_WANT_OPTIONAL_GPIOLIB
52 select BUILDTIME_EXTABLE_SORT
54 select CLKSRC_I8253 if X86_32
55 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
56 select CLOCKSOURCE_WATCHDOG
57 select CLONE_BACKWARDS if X86_32
58 select COMPAT_OLD_SIGACTION if IA32_EMULATION
59 select DCACHE_WORD_ACCESS
60 select EDAC_ATOMIC_SCRUB
62 select GENERIC_CLOCKEVENTS
63 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
64 select GENERIC_CLOCKEVENTS_MIN_ADJUST
65 select GENERIC_CMOS_UPDATE
66 select GENERIC_CPU_AUTOPROBE
67 select GENERIC_EARLY_IOREMAP
68 select GENERIC_FIND_FIRST_BIT
70 select GENERIC_IRQ_PROBE
71 select GENERIC_IRQ_SHOW
72 select GENERIC_PENDING_IRQ if SMP
73 select GENERIC_SMP_IDLE_THREAD
74 select GENERIC_STRNCPY_FROM_USER
75 select GENERIC_STRNLEN_USER
76 select GENERIC_TIME_VSYSCALL
77 select HAVE_ACPI_APEI if ACPI
78 select HAVE_ACPI_APEI_NMI if ACPI
79 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
80 select HAVE_AOUT if X86_32
81 select HAVE_ARCH_AUDITSYSCALL
82 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
83 select HAVE_ARCH_JUMP_LABEL
84 select HAVE_ARCH_KASAN if X86_64 && SPARSEMEM_VMEMMAP
86 select HAVE_ARCH_KMEMCHECK
87 select HAVE_ARCH_SECCOMP_FILTER
88 select HAVE_ARCH_SOFT_DIRTY if X86_64
89 select HAVE_ARCH_TRACEHOOK
90 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
91 select HAVE_BPF_JIT if X86_64
92 select HAVE_CC_STACKPROTECTOR
93 select HAVE_CMPXCHG_DOUBLE
94 select HAVE_CMPXCHG_LOCAL
95 select HAVE_CONTEXT_TRACKING if X86_64
96 select HAVE_COPY_THREAD_TLS
97 select HAVE_C_RECORDMCOUNT
98 select HAVE_DEBUG_KMEMLEAK
99 select HAVE_DEBUG_STACKOVERFLOW
100 select HAVE_DMA_API_DEBUG
101 select HAVE_DMA_ATTRS
102 select HAVE_DMA_CONTIGUOUS
103 select HAVE_DYNAMIC_FTRACE
104 select HAVE_DYNAMIC_FTRACE_WITH_REGS
105 select HAVE_EFFICIENT_UNALIGNED_ACCESS
106 select HAVE_FENTRY if X86_64
107 select HAVE_FTRACE_MCOUNT_RECORD
108 select HAVE_FUNCTION_GRAPH_FP_TEST
109 select HAVE_FUNCTION_GRAPH_TRACER
110 select HAVE_FUNCTION_TRACER
111 select HAVE_GENERIC_DMA_COHERENT if X86_32
112 select HAVE_HW_BREAKPOINT
114 select HAVE_IOREMAP_PROT
115 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
116 select HAVE_IRQ_TIME_ACCOUNTING
117 select HAVE_KERNEL_BZIP2
118 select HAVE_KERNEL_GZIP
119 select HAVE_KERNEL_LZ4
120 select HAVE_KERNEL_LZMA
121 select HAVE_KERNEL_LZO
122 select HAVE_KERNEL_XZ
124 select HAVE_KPROBES_ON_FTRACE
125 select HAVE_KRETPROBES
127 select HAVE_LIVEPATCH if X86_64
129 select HAVE_MEMBLOCK_NODE_MAP
130 select HAVE_MIXED_BREAKPOINTS_REGS
132 select HAVE_OPTPROBES
133 select HAVE_PCSPKR_PLATFORM
134 select HAVE_PERF_EVENTS
135 select HAVE_PERF_EVENTS_NMI
136 select HAVE_PERF_REGS
137 select HAVE_PERF_USER_STACK_DUMP
138 select HAVE_REGS_AND_STACK_ACCESS_API
139 select HAVE_SYSCALL_TRACEPOINTS
140 select HAVE_UID16 if X86_32 || IA32_EMULATION
141 select HAVE_UNSTABLE_SCHED_CLOCK
142 select HAVE_USER_RETURN_NOTIFIER
143 select IRQ_FORCED_THREADING
144 select MODULES_USE_ELF_RELA if X86_64
145 select MODULES_USE_ELF_REL if X86_32
146 select OLD_SIGACTION if X86_32
147 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
152 select SYSCTL_EXCEPTION_TRACE
153 select USER_STACKTRACE_SUPPORT
155 select X86_DEV_DMA_OPS if X86_64
156 select X86_FEATURE_NAMES if PROC_FS
158 config INSTRUCTION_DECODER
160 depends on KPROBES || PERF_EVENTS || UPROBES
162 config PERF_EVENTS_INTEL_UNCORE
164 depends on PERF_EVENTS && CPU_SUP_INTEL && PCI
168 default "elf32-i386" if X86_32
169 default "elf64-x86-64" if X86_64
171 config ARCH_DEFCONFIG
173 default "arch/x86/configs/i386_defconfig" if X86_32
174 default "arch/x86/configs/x86_64_defconfig" if X86_64
176 config LOCKDEP_SUPPORT
179 config STACKTRACE_SUPPORT
182 config HAVE_LATENCYTOP_SUPPORT
188 config ARCH_MMAP_RND_BITS_MIN
192 config ARCH_MMAP_RND_BITS_MAX
196 config ARCH_MMAP_RND_COMPAT_BITS_MIN
199 config ARCH_MMAP_RND_COMPAT_BITS_MAX
205 config NEED_DMA_MAP_STATE
207 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
209 config NEED_SG_DMA_LENGTH
212 config GENERIC_ISA_DMA
214 depends on ISA_DMA_API
219 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
221 config GENERIC_BUG_RELATIVE_POINTERS
224 config GENERIC_HWEIGHT
227 config ARCH_MAY_HAVE_PC_FDC
229 depends on ISA_DMA_API
231 config RWSEM_XCHGADD_ALGORITHM
234 config GENERIC_CALIBRATE_DELAY
237 config ARCH_HAS_CPU_RELAX
240 config ARCH_HAS_CACHE_LINE_SIZE
243 config HAVE_SETUP_PER_CPU_AREA
246 config NEED_PER_CPU_EMBED_FIRST_CHUNK
249 config NEED_PER_CPU_PAGE_FIRST_CHUNK
252 config ARCH_HIBERNATION_POSSIBLE
255 config ARCH_SUSPEND_POSSIBLE
258 config ARCH_WANT_HUGE_PMD_SHARE
261 config ARCH_WANT_GENERAL_HUGETLB
270 config ARCH_SUPPORTS_OPTIMIZED_INLINING
273 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
276 config KASAN_SHADOW_OFFSET
279 default 0xdffffc0000000000
281 config HAVE_INTEL_TXT
283 depends on INTEL_IOMMU && ACPI
287 depends on X86_32 && SMP
291 depends on X86_64 && SMP
293 config X86_32_LAZY_GS
295 depends on X86_32 && !CC_STACKPROTECTOR
297 config ARCH_HWEIGHT_CFLAGS
299 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
300 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
302 config ARCH_SUPPORTS_UPROBES
305 config FIX_EARLYCON_MEM
311 config PGTABLE_LEVELS
317 source "init/Kconfig"
318 source "kernel/Kconfig.freezer"
320 menu "Processor type and features"
323 bool "DMA memory allocation support" if EXPERT
326 DMA memory allocation support allows devices with less than 32-bit
327 addressing to allocate within the first 16MB of address space.
328 Disable if no such devices will be used.
333 bool "Symmetric multi-processing support"
335 This enables support for systems with more than one CPU. If you have
336 a system with only one CPU, say N. If you have a system with more
339 If you say N here, the kernel will run on uni- and multiprocessor
340 machines, but will use only one CPU of a multiprocessor machine. If
341 you say Y here, the kernel will run on many, but not all,
342 uniprocessor machines. On a uniprocessor machine, the kernel
343 will run faster if you say N here.
345 Note that if you say Y here and choose architecture "586" or
346 "Pentium" under "Processor family", the kernel will not work on 486
347 architectures. Similarly, multiprocessor kernels for the "PPro"
348 architecture may not work on all Pentium based boards.
350 People using multiprocessor machines who say Y here should also say
351 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
352 Management" code will be disabled if you say Y here.
354 See also <file:Documentation/x86/i386/IO-APIC.txt>,
355 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
356 <http://www.tldp.org/docs.html#howto>.
358 If you don't know what to do here, say N.
360 config X86_FEATURE_NAMES
361 bool "Processor feature human-readable names" if EMBEDDED
364 This option compiles in a table of x86 feature bits and corresponding
365 names. This is required to support /proc/cpuinfo and a few kernel
366 messages. You can disable this to save space, at the expense of
367 making those few kernel messages show numeric feature bits instead.
372 bool "Support x2apic"
373 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
375 This enables x2apic support on CPUs that have this feature.
377 This allows 32-bit apic IDs (so it can support very large systems),
378 and accesses the local apic via MSRs not via mmio.
380 If you don't know what to do here, say N.
383 bool "Enable MPS table" if ACPI || SFI
385 depends on X86_LOCAL_APIC
387 For old smp systems that do not have proper acpi support. Newer systems
388 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
391 bool "Support for big SMP systems with more than 8 CPUs"
392 depends on X86_32 && SMP
394 This option is needed for the systems that have more than 8 CPUs
398 depends on X86_GOLDFISH
401 config X86_EXTENDED_PLATFORM
402 bool "Support for extended (non-PC) x86 platforms"
405 If you disable this option then the kernel will only support
406 standard PC platforms. (which covers the vast majority of
409 If you enable this option then you'll be able to select support
410 for the following (non-PC) 32 bit x86 platforms:
411 Goldfish (Android emulator)
414 SGI 320/540 (Visual Workstation)
415 STA2X11-based (e.g. Northville)
416 Moorestown MID devices
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.
423 config X86_EXTENDED_PLATFORM
424 bool "Support for extended (non-PC) x86 platforms"
427 If you disable this option then the kernel will only support
428 standard PC platforms. (which covers the vast majority of
431 If you enable this option then you'll be able to select support
432 for the following (non-PC) 64 bit x86 platforms:
437 If you have one of these systems, or if you want to build a
438 generic distribution kernel, say Y here - otherwise say N.
440 # This is an alphabetically sorted list of 64 bit extended platforms
441 # Please maintain the alphabetic order if and when there are additions
443 bool "Numascale NumaChip"
445 depends on X86_EXTENDED_PLATFORM
448 depends on X86_X2APIC
449 depends on PCI_MMCONFIG
451 Adds support for Numascale NumaChip large-SMP systems. Needed to
452 enable more than ~168 cores.
453 If you don't have one of these, you should say N here.
457 select HYPERVISOR_GUEST
459 depends on X86_64 && PCI
460 depends on X86_EXTENDED_PLATFORM
463 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
464 supposed to run on these EM64T-based machines. Only choose this option
465 if you have one of these machines.
468 bool "SGI Ultraviolet"
470 depends on X86_EXTENDED_PLATFORM
472 depends on X86_X2APIC
475 This option is needed in order to support SGI Ultraviolet systems.
476 If you don't have one of these, you should say N here.
478 # Following is an alphabetically sorted list of 32 bit extended platforms
479 # Please maintain the alphabetic order if and when there are additions
482 bool "Goldfish (Virtual Platform)"
483 depends on X86_EXTENDED_PLATFORM
485 Enable support for the Goldfish virtual platform used primarily
486 for Android development. Unless you are building for the Android
487 Goldfish emulator say N here.
490 bool "CE4100 TV platform"
492 depends on PCI_GODIRECT
493 depends on X86_IO_APIC
495 depends on X86_EXTENDED_PLATFORM
496 select X86_REBOOTFIXUPS
498 select OF_EARLY_FLATTREE
500 Select for the Intel CE media processor (CE4100) SOC.
501 This option compiles in support for the CE4100 SOC for settop
502 boxes and media devices.
505 bool "Intel MID platform support"
507 depends on X86_EXTENDED_PLATFORM
508 depends on X86_PLATFORM_DEVICES
511 depends on X86_IO_APIC
517 select MFD_INTEL_MSIC
519 Select to build a kernel capable of supporting Intel MID (Mobile
520 Internet Device) platform systems which do not have the PCI legacy
521 interfaces. If you are building for a PC class system say N here.
523 Intel MID platforms are based on an Intel processor and chipset which
524 consume less power than most of the x86 derivatives.
526 config X86_INTEL_QUARK
527 bool "Intel Quark platform support"
529 depends on X86_EXTENDED_PLATFORM
530 depends on X86_PLATFORM_DEVICES
534 depends on X86_IO_APIC
539 Select to include support for Quark X1000 SoC.
540 Say Y here if you have a Quark based system such as the Arduino
541 compatible Intel Galileo.
543 config X86_INTEL_LPSS
544 bool "Intel Low Power Subsystem Support"
549 Select to build support for Intel Low Power Subsystem such as
550 found on Intel Lynxpoint PCH. Selecting this option enables
551 things like clock tree (common clock framework) and pincontrol
552 which are needed by the LPSS peripheral drivers.
554 config X86_AMD_PLATFORM_DEVICE
555 bool "AMD ACPI2Platform devices support"
560 Select to interpret AMD specific ACPI device to platform device
561 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
562 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
563 implemented under PINCTRL subsystem.
566 tristate "Intel SoC IOSF Sideband support for SoC platforms"
569 This option enables sideband register access support for Intel SoC
570 platforms. On these platforms the IOSF sideband is used in lieu of
571 MSR's for some register accesses, mostly but not limited to thermal
572 and power. Drivers may query the availability of this device to
573 determine if they need the sideband in order to work on these
574 platforms. The sideband is available on the following SoC products.
575 This list is not meant to be exclusive.
580 You should say Y if you are running a kernel on one of these SoC's.
582 config IOSF_MBI_DEBUG
583 bool "Enable IOSF sideband access through debugfs"
584 depends on IOSF_MBI && DEBUG_FS
586 Select this option to expose the IOSF sideband access registers (MCR,
587 MDR, MCRX) through debugfs to write and read register information from
588 different units on the SoC. This is most useful for obtaining device
589 state information for debug and analysis. As this is a general access
590 mechanism, users of this option would have specific knowledge of the
591 device they want to access.
593 If you don't require the option or are in doubt, say N.
596 bool "RDC R-321x SoC"
598 depends on X86_EXTENDED_PLATFORM
600 select X86_REBOOTFIXUPS
602 This option is needed for RDC R-321x system-on-chip, also known
604 If you don't have one of these chips, you should say N here.
606 config X86_32_NON_STANDARD
607 bool "Support non-standard 32-bit SMP architectures"
608 depends on X86_32 && SMP
609 depends on X86_EXTENDED_PLATFORM
611 This option compiles in the bigsmp and STA2X11 default
612 subarchitectures. It is intended for a generic binary
613 kernel. If you select them all, kernel will probe it one by
614 one and will fallback to default.
616 # Alphabetically sorted list of Non standard 32 bit platforms
618 config X86_SUPPORTS_MEMORY_FAILURE
620 # MCE code calls memory_failure():
622 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
623 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
624 depends on X86_64 || !SPARSEMEM
625 select ARCH_SUPPORTS_MEMORY_FAILURE
628 bool "STA2X11 Companion Chip Support"
629 depends on X86_32_NON_STANDARD && PCI
630 select X86_DEV_DMA_OPS
634 select ARCH_REQUIRE_GPIOLIB
637 This adds support for boards based on the STA2X11 IO-Hub,
638 a.k.a. "ConneXt". The chip is used in place of the standard
639 PC chipset, so all "standard" peripherals are missing. If this
640 option is selected the kernel will still be able to boot on
641 standard PC machines.
644 tristate "Eurobraille/Iris poweroff module"
647 The Iris machines from EuroBraille do not have APM or ACPI support
648 to shut themselves down properly. A special I/O sequence is
649 needed to do so, which is what this module does at
652 This is only for Iris machines from EuroBraille.
656 config SCHED_OMIT_FRAME_POINTER
658 prompt "Single-depth WCHAN output"
661 Calculate simpler /proc/<PID>/wchan values. If this option
662 is disabled then wchan values will recurse back to the
663 caller function. This provides more accurate wchan values,
664 at the expense of slightly more scheduling overhead.
666 If in doubt, say "Y".
668 menuconfig HYPERVISOR_GUEST
669 bool "Linux guest support"
671 Say Y here to enable options for running Linux under various hyper-
672 visors. This option enables basic hypervisor detection and platform
675 If you say N, all options in this submenu will be skipped and
676 disabled, and Linux guest support won't be built in.
681 bool "Enable paravirtualization code"
683 This changes the kernel so it can modify itself when it is run
684 under a hypervisor, potentially improving performance significantly
685 over full virtualization. However, when run without a hypervisor
686 the kernel is theoretically slower and slightly larger.
688 config PARAVIRT_DEBUG
689 bool "paravirt-ops debugging"
690 depends on PARAVIRT && DEBUG_KERNEL
692 Enable to debug paravirt_ops internals. Specifically, BUG if
693 a paravirt_op is missing when it is called.
695 config PARAVIRT_SPINLOCKS
696 bool "Paravirtualization layer for spinlocks"
697 depends on PARAVIRT && SMP
698 select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS
700 Paravirtualized spinlocks allow a pvops backend to replace the
701 spinlock implementation with something virtualization-friendly
702 (for example, block the virtual CPU rather than spinning).
704 It has a minimal impact on native kernels and gives a nice performance
705 benefit on paravirtualized KVM / Xen kernels.
707 If you are unsure how to answer this question, answer Y.
709 source "arch/x86/xen/Kconfig"
712 bool "KVM Guest support (including kvmclock)"
714 select PARAVIRT_CLOCK
717 This option enables various optimizations for running under the KVM
718 hypervisor. It includes a paravirtualized clock, so that instead
719 of relying on a PIT (or probably other) emulation by the
720 underlying device model, the host provides the guest with
721 timing infrastructure such as time of day, and system time
724 bool "Enable debug information for KVM Guests in debugfs"
725 depends on KVM_GUEST && DEBUG_FS
728 This option enables collection of various statistics for KVM guest.
729 Statistics are displayed in debugfs filesystem. Enabling this option
730 may incur significant overhead.
732 source "arch/x86/lguest/Kconfig"
734 config PARAVIRT_TIME_ACCOUNTING
735 bool "Paravirtual steal time accounting"
739 Select this option to enable fine granularity task steal time
740 accounting. Time spent executing other tasks in parallel with
741 the current vCPU is discounted from the vCPU power. To account for
742 that, there can be a small performance impact.
744 If in doubt, say N here.
746 config PARAVIRT_CLOCK
749 endif #HYPERVISOR_GUEST
754 source "arch/x86/Kconfig.cpu"
758 prompt "HPET Timer Support" if X86_32
760 Use the IA-PC HPET (High Precision Event Timer) to manage
761 time in preference to the PIT and RTC, if a HPET is
763 HPET is the next generation timer replacing legacy 8254s.
764 The HPET provides a stable time base on SMP
765 systems, unlike the TSC, but it is more expensive to access,
766 as it is off-chip. You can find the HPET spec at
767 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
769 You can safely choose Y here. However, HPET will only be
770 activated if the platform and the BIOS support this feature.
771 Otherwise the 8254 will be used for timing services.
773 Choose N to continue using the legacy 8254 timer.
775 config HPET_EMULATE_RTC
777 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
780 def_bool y if X86_INTEL_MID
781 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
783 depends on X86_INTEL_MID && SFI
785 APB timer is the replacement for 8254, HPET on X86 MID platforms.
786 The APBT provides a stable time base on SMP
787 systems, unlike the TSC, but it is more expensive to access,
788 as it is off-chip. APB timers are always running regardless of CPU
789 C states, they are used as per CPU clockevent device when possible.
791 # Mark as expert because too many people got it wrong.
792 # The code disables itself when not needed.
795 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
796 bool "Enable DMI scanning" if EXPERT
798 Enabled scanning of DMI to identify machine quirks. Say Y
799 here unless you have verified that your setup is not
800 affected by entries in the DMI blacklist. Required by PNP
804 bool "Old AMD GART IOMMU support"
806 depends on X86_64 && PCI && AMD_NB
808 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
809 GART based hardware IOMMUs.
811 The GART supports full DMA access for devices with 32-bit access
812 limitations, on systems with more than 3 GB. This is usually needed
813 for USB, sound, many IDE/SATA chipsets and some other devices.
815 Newer systems typically have a modern AMD IOMMU, supported via
816 the CONFIG_AMD_IOMMU=y config option.
818 In normal configurations this driver is only active when needed:
819 there's more than 3 GB of memory and the system contains a
820 32-bit limited device.
825 bool "IBM Calgary IOMMU support"
827 depends on X86_64 && PCI
829 Support for hardware IOMMUs in IBM's xSeries x366 and x460
830 systems. Needed to run systems with more than 3GB of memory
831 properly with 32-bit PCI devices that do not support DAC
832 (Double Address Cycle). Calgary also supports bus level
833 isolation, where all DMAs pass through the IOMMU. This
834 prevents them from going anywhere except their intended
835 destination. This catches hard-to-find kernel bugs and
836 mis-behaving drivers and devices that do not use the DMA-API
837 properly to set up their DMA buffers. The IOMMU can be
838 turned off at boot time with the iommu=off parameter.
839 Normally the kernel will make the right choice by itself.
842 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
844 prompt "Should Calgary be enabled by default?"
845 depends on CALGARY_IOMMU
847 Should Calgary be enabled by default? if you choose 'y', Calgary
848 will be used (if it exists). If you choose 'n', Calgary will not be
849 used even if it exists. If you choose 'n' and would like to use
850 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
853 # need this always selected by IOMMU for the VIA workaround
857 Support for software bounce buffers used on x86-64 systems
858 which don't have a hardware IOMMU. Using this PCI devices
859 which can only access 32-bits of memory can be used on systems
860 with more than 3 GB of memory.
865 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
868 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
869 depends on X86_64 && SMP && DEBUG_KERNEL
870 select CPUMASK_OFFSTACK
872 Enable maximum number of CPUS and NUMA Nodes for this architecture.
876 int "Maximum number of CPUs" if SMP && !MAXSMP
877 range 2 8 if SMP && X86_32 && !X86_BIGSMP
878 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
879 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
881 default "8192" if MAXSMP
882 default "32" if SMP && X86_BIGSMP
883 default "8" if SMP && X86_32
886 This allows you to specify the maximum number of CPUs which this
887 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
888 supported value is 8192, otherwise the maximum value is 512. The
889 minimum value which makes sense is 2.
891 This is purely to save memory - each supported CPU adds
892 approximately eight kilobytes to the kernel image.
895 bool "SMT (Hyperthreading) scheduler support"
898 SMT scheduler support improves the CPU scheduler's decision making
899 when dealing with Intel Pentium 4 chips with HyperThreading at a
900 cost of slightly increased overhead in some places. If unsure say
905 prompt "Multi-core scheduler support"
908 Multi-core scheduler support improves the CPU scheduler's decision
909 making when dealing with multi-core CPU chips at a cost of slightly
910 increased overhead in some places. If unsure say N here.
912 source "kernel/Kconfig.preempt"
916 depends on !SMP && X86_LOCAL_APIC
919 bool "Local APIC support on uniprocessors" if !PCI_MSI
921 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
923 A local APIC (Advanced Programmable Interrupt Controller) is an
924 integrated interrupt controller in the CPU. If you have a single-CPU
925 system which has a processor with a local APIC, you can say Y here to
926 enable and use it. If you say Y here even though your machine doesn't
927 have a local APIC, then the kernel will still run with no slowdown at
928 all. The local APIC supports CPU-generated self-interrupts (timer,
929 performance counters), and the NMI watchdog which detects hard
933 bool "IO-APIC support on uniprocessors"
934 depends on X86_UP_APIC
936 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
937 SMP-capable replacement for PC-style interrupt controllers. Most
938 SMP systems and many recent uniprocessor systems have one.
940 If you have a single-CPU system with an IO-APIC, you can say Y here
941 to use it. If you say Y here even though your machine doesn't have
942 an IO-APIC, then the kernel will still run with no slowdown at all.
944 config X86_LOCAL_APIC
946 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
947 select IRQ_DOMAIN_HIERARCHY
948 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
952 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
954 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
955 bool "Reroute for broken boot IRQs"
956 depends on X86_IO_APIC
958 This option enables a workaround that fixes a source of
959 spurious interrupts. This is recommended when threaded
960 interrupt handling is used on systems where the generation of
961 superfluous "boot interrupts" cannot be disabled.
963 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
964 entry in the chipset's IO-APIC is masked (as, e.g. the RT
965 kernel does during interrupt handling). On chipsets where this
966 boot IRQ generation cannot be disabled, this workaround keeps
967 the original IRQ line masked so that only the equivalent "boot
968 IRQ" is delivered to the CPUs. The workaround also tells the
969 kernel to set up the IRQ handler on the boot IRQ line. In this
970 way only one interrupt is delivered to the kernel. Otherwise
971 the spurious second interrupt may cause the kernel to bring
972 down (vital) interrupt lines.
974 Only affects "broken" chipsets. Interrupt sharing may be
975 increased on these systems.
978 bool "Machine Check / overheating reporting"
979 select GENERIC_ALLOCATOR
982 Machine Check support allows the processor to notify the
983 kernel if it detects a problem (e.g. overheating, data corruption).
984 The action the kernel takes depends on the severity of the problem,
985 ranging from warning messages to halting the machine.
989 prompt "Intel MCE features"
990 depends on X86_MCE && X86_LOCAL_APIC
992 Additional support for intel specific MCE features such as
997 prompt "AMD MCE features"
998 depends on X86_MCE && X86_LOCAL_APIC
1000 Additional support for AMD specific MCE features such as
1001 the DRAM Error Threshold.
1003 config X86_ANCIENT_MCE
1004 bool "Support for old Pentium 5 / WinChip machine checks"
1005 depends on X86_32 && X86_MCE
1007 Include support for machine check handling on old Pentium 5 or WinChip
1008 systems. These typically need to be enabled explicitly on the command
1011 config X86_MCE_THRESHOLD
1012 depends on X86_MCE_AMD || X86_MCE_INTEL
1015 config X86_MCE_INJECT
1017 tristate "Machine check injector support"
1019 Provide support for injecting machine checks for testing purposes.
1020 If you don't know what a machine check is and you don't do kernel
1021 QA it is safe to say n.
1023 config X86_THERMAL_VECTOR
1025 depends on X86_MCE_INTEL
1027 config X86_LEGACY_VM86
1028 bool "Legacy VM86 support"
1032 This option allows user programs to put the CPU into V8086
1033 mode, which is an 80286-era approximation of 16-bit real mode.
1035 Some very old versions of X and/or vbetool require this option
1036 for user mode setting. Similarly, DOSEMU will use it if
1037 available to accelerate real mode DOS programs. However, any
1038 recent version of DOSEMU, X, or vbetool should be fully
1039 functional even without kernel VM86 support, as they will all
1040 fall back to software emulation. Nevertheless, if you are using
1041 a 16-bit DOS program where 16-bit performance matters, vm86
1042 mode might be faster than emulation and you might want to
1045 Note that any app that works on a 64-bit kernel is unlikely to
1046 need this option, as 64-bit kernels don't, and can't, support
1047 V8086 mode. This option is also unrelated to 16-bit protected
1048 mode and is not needed to run most 16-bit programs under Wine.
1050 Enabling this option increases the complexity of the kernel
1051 and slows down exception handling a tiny bit.
1053 If unsure, say N here.
1057 default X86_LEGACY_VM86
1060 bool "Enable support for 16-bit segments" if EXPERT
1062 depends on MODIFY_LDT_SYSCALL
1064 This option is required by programs like Wine to run 16-bit
1065 protected mode legacy code on x86 processors. Disabling
1066 this option saves about 300 bytes on i386, or around 6K text
1067 plus 16K runtime memory on x86-64,
1071 depends on X86_16BIT && X86_32
1075 depends on X86_16BIT && X86_64
1077 config X86_VSYSCALL_EMULATION
1078 bool "Enable vsyscall emulation" if EXPERT
1082 This enables emulation of the legacy vsyscall page. Disabling
1083 it is roughly equivalent to booting with vsyscall=none, except
1084 that it will also disable the helpful warning if a program
1085 tries to use a vsyscall. With this option set to N, offending
1086 programs will just segfault, citing addresses of the form
1089 This option is required by many programs built before 2013, and
1090 care should be used even with newer programs if set to N.
1092 Disabling this option saves about 7K of kernel size and
1093 possibly 4K of additional runtime pagetable memory.
1096 tristate "Toshiba Laptop support"
1099 This adds a driver to safely access the System Management Mode of
1100 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1101 not work on models with a Phoenix BIOS. The System Management Mode
1102 is used to set the BIOS and power saving options on Toshiba portables.
1104 For information on utilities to make use of this driver see the
1105 Toshiba Linux utilities web site at:
1106 <http://www.buzzard.org.uk/toshiba/>.
1108 Say Y if you intend to run this kernel on a Toshiba portable.
1112 tristate "Dell i8k legacy laptop support"
1114 select SENSORS_DELL_SMM
1116 This option enables legacy /proc/i8k userspace interface in hwmon
1117 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1118 temperature and allows controlling fan speeds of Dell laptops via
1119 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1120 it reports also power and hotkey status. For fan speed control is
1121 needed userspace package i8kutils.
1123 Say Y if you intend to run this kernel on old Dell laptops or want to
1124 use userspace package i8kutils.
1127 config X86_REBOOTFIXUPS
1128 bool "Enable X86 board specific fixups for reboot"
1131 This enables chipset and/or board specific fixups to be done
1132 in order to get reboot to work correctly. This is only needed on
1133 some combinations of hardware and BIOS. The symptom, for which
1134 this config is intended, is when reboot ends with a stalled/hung
1137 Currently, the only fixup is for the Geode machines using
1138 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1140 Say Y if you want to enable the fixup. Currently, it's safe to
1141 enable this option even if you don't need it.
1145 bool "CPU microcode loading support"
1147 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1150 If you say Y here, you will be able to update the microcode on
1151 Intel and AMD processors. The Intel support is for the IA32 family,
1152 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1153 AMD support is for families 0x10 and later. You will obviously need
1154 the actual microcode binary data itself which is not shipped with
1157 The preferred method to load microcode from a detached initrd is described
1158 in Documentation/x86/early-microcode.txt. For that you need to enable
1159 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1160 initrd for microcode blobs.
1162 In addition, you can build-in the microcode into the kernel. For that you
1163 need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
1164 to the CONFIG_EXTRA_FIRMWARE config option.
1166 config MICROCODE_INTEL
1167 bool "Intel microcode loading support"
1168 depends on MICROCODE
1172 This options enables microcode patch loading support for Intel
1175 For the current Intel microcode data package go to
1176 <https://downloadcenter.intel.com> and search for
1177 'Linux Processor Microcode Data File'.
1179 config MICROCODE_AMD
1180 bool "AMD microcode loading support"
1181 depends on MICROCODE
1184 If you select this option, microcode patch loading support for AMD
1185 processors will be enabled.
1187 config MICROCODE_OLD_INTERFACE
1189 depends on MICROCODE
1192 tristate "/dev/cpu/*/msr - Model-specific register support"
1194 This device gives privileged processes access to the x86
1195 Model-Specific Registers (MSRs). It is a character device with
1196 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1197 MSR accesses are directed to a specific CPU on multi-processor
1201 tristate "/dev/cpu/*/cpuid - CPU information support"
1203 This device gives processes access to the x86 CPUID instruction to
1204 be executed on a specific processor. It is a character device
1205 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1209 prompt "High Memory Support"
1216 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1217 However, the address space of 32-bit x86 processors is only 4
1218 Gigabytes large. That means that, if you have a large amount of
1219 physical memory, not all of it can be "permanently mapped" by the
1220 kernel. The physical memory that's not permanently mapped is called
1223 If you are compiling a kernel which will never run on a machine with
1224 more than 1 Gigabyte total physical RAM, answer "off" here (default
1225 choice and suitable for most users). This will result in a "3GB/1GB"
1226 split: 3GB are mapped so that each process sees a 3GB virtual memory
1227 space and the remaining part of the 4GB virtual memory space is used
1228 by the kernel to permanently map as much physical memory as
1231 If the machine has between 1 and 4 Gigabytes physical RAM, then
1234 If more than 4 Gigabytes is used then answer "64GB" here. This
1235 selection turns Intel PAE (Physical Address Extension) mode on.
1236 PAE implements 3-level paging on IA32 processors. PAE is fully
1237 supported by Linux, PAE mode is implemented on all recent Intel
1238 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1239 then the kernel will not boot on CPUs that don't support PAE!
1241 The actual amount of total physical memory will either be
1242 auto detected or can be forced by using a kernel command line option
1243 such as "mem=256M". (Try "man bootparam" or see the documentation of
1244 your boot loader (lilo or loadlin) about how to pass options to the
1245 kernel at boot time.)
1247 If unsure, say "off".
1252 Select this if you have a 32-bit processor and between 1 and 4
1253 gigabytes of physical RAM.
1260 Select this if you have a 32-bit processor and more than 4
1261 gigabytes of physical RAM.
1266 prompt "Memory split" if EXPERT
1270 Select the desired split between kernel and user memory.
1272 If the address range available to the kernel is less than the
1273 physical memory installed, the remaining memory will be available
1274 as "high memory". Accessing high memory is a little more costly
1275 than low memory, as it needs to be mapped into the kernel first.
1276 Note that increasing the kernel address space limits the range
1277 available to user programs, making the address space there
1278 tighter. Selecting anything other than the default 3G/1G split
1279 will also likely make your kernel incompatible with binary-only
1282 If you are not absolutely sure what you are doing, leave this
1286 bool "3G/1G user/kernel split"
1287 config VMSPLIT_3G_OPT
1289 bool "3G/1G user/kernel split (for full 1G low memory)"
1291 bool "2G/2G user/kernel split"
1292 config VMSPLIT_2G_OPT
1294 bool "2G/2G user/kernel split (for full 2G low memory)"
1296 bool "1G/3G user/kernel split"
1301 default 0xB0000000 if VMSPLIT_3G_OPT
1302 default 0x80000000 if VMSPLIT_2G
1303 default 0x78000000 if VMSPLIT_2G_OPT
1304 default 0x40000000 if VMSPLIT_1G
1310 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1313 bool "PAE (Physical Address Extension) Support"
1314 depends on X86_32 && !HIGHMEM4G
1317 PAE is required for NX support, and furthermore enables
1318 larger swapspace support for non-overcommit purposes. It
1319 has the cost of more pagetable lookup overhead, and also
1320 consumes more pagetable space per process.
1322 config ARCH_PHYS_ADDR_T_64BIT
1324 depends on X86_64 || X86_PAE
1326 config ARCH_DMA_ADDR_T_64BIT
1328 depends on X86_64 || HIGHMEM64G
1330 config X86_DIRECT_GBPAGES
1332 depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1334 Certain kernel features effectively disable kernel
1335 linear 1 GB mappings (even if the CPU otherwise
1336 supports them), so don't confuse the user by printing
1337 that we have them enabled.
1339 # Common NUMA Features
1341 bool "Numa Memory Allocation and Scheduler Support"
1343 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1344 default y if X86_BIGSMP
1346 Enable NUMA (Non Uniform Memory Access) support.
1348 The kernel will try to allocate memory used by a CPU on the
1349 local memory controller of the CPU and add some more
1350 NUMA awareness to the kernel.
1352 For 64-bit this is recommended if the system is Intel Core i7
1353 (or later), AMD Opteron, or EM64T NUMA.
1355 For 32-bit this is only needed if you boot a 32-bit
1356 kernel on a 64-bit NUMA platform.
1358 Otherwise, you should say N.
1362 prompt "Old style AMD Opteron NUMA detection"
1363 depends on X86_64 && NUMA && PCI
1365 Enable AMD NUMA node topology detection. You should say Y here if
1366 you have a multi processor AMD system. This uses an old method to
1367 read the NUMA configuration directly from the builtin Northbridge
1368 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1369 which also takes priority if both are compiled in.
1371 config X86_64_ACPI_NUMA
1373 prompt "ACPI NUMA detection"
1374 depends on X86_64 && NUMA && ACPI && PCI
1377 Enable ACPI SRAT based node topology detection.
1379 # Some NUMA nodes have memory ranges that span
1380 # other nodes. Even though a pfn is valid and
1381 # between a node's start and end pfns, it may not
1382 # reside on that node. See memmap_init_zone()
1384 config NODES_SPAN_OTHER_NODES
1386 depends on X86_64_ACPI_NUMA
1389 bool "NUMA emulation"
1392 Enable NUMA emulation. A flat machine will be split
1393 into virtual nodes when booted with "numa=fake=N", where N is the
1394 number of nodes. This is only useful for debugging.
1397 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1399 default "10" if MAXSMP
1400 default "6" if X86_64
1402 depends on NEED_MULTIPLE_NODES
1404 Specify the maximum number of NUMA Nodes available on the target
1405 system. Increases memory reserved to accommodate various tables.
1407 config ARCH_HAVE_MEMORY_PRESENT
1409 depends on X86_32 && DISCONTIGMEM
1411 config NEED_NODE_MEMMAP_SIZE
1413 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1415 config ARCH_FLATMEM_ENABLE
1417 depends on X86_32 && !NUMA
1419 config ARCH_DISCONTIGMEM_ENABLE
1421 depends on NUMA && X86_32
1423 config ARCH_DISCONTIGMEM_DEFAULT
1425 depends on NUMA && X86_32
1427 config ARCH_SPARSEMEM_ENABLE
1429 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1430 select SPARSEMEM_STATIC if X86_32
1431 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1433 config ARCH_SPARSEMEM_DEFAULT
1437 config ARCH_SELECT_MEMORY_MODEL
1439 depends on ARCH_SPARSEMEM_ENABLE
1441 config ARCH_MEMORY_PROBE
1442 bool "Enable sysfs memory/probe interface"
1443 depends on X86_64 && MEMORY_HOTPLUG
1445 This option enables a sysfs memory/probe interface for testing.
1446 See Documentation/memory-hotplug.txt for more information.
1447 If you are unsure how to answer this question, answer N.
1449 config ARCH_PROC_KCORE_TEXT
1451 depends on X86_64 && PROC_KCORE
1453 config ILLEGAL_POINTER_VALUE
1456 default 0xdead000000000000 if X86_64
1460 config X86_PMEM_LEGACY_DEVICE
1463 config X86_PMEM_LEGACY
1464 tristate "Support non-standard NVDIMMs and ADR protected memory"
1465 depends on PHYS_ADDR_T_64BIT
1467 select X86_PMEM_LEGACY_DEVICE
1470 Treat memory marked using the non-standard e820 type of 12 as used
1471 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1472 The kernel will offer these regions to the 'pmem' driver so
1473 they can be used for persistent storage.
1478 bool "Allocate 3rd-level pagetables from highmem"
1481 The VM uses one page table entry for each page of physical memory.
1482 For systems with a lot of RAM, this can be wasteful of precious
1483 low memory. Setting this option will put user-space page table
1484 entries in high memory.
1486 config X86_CHECK_BIOS_CORRUPTION
1487 bool "Check for low memory corruption"
1489 Periodically check for memory corruption in low memory, which
1490 is suspected to be caused by BIOS. Even when enabled in the
1491 configuration, it is disabled at runtime. Enable it by
1492 setting "memory_corruption_check=1" on the kernel command
1493 line. By default it scans the low 64k of memory every 60
1494 seconds; see the memory_corruption_check_size and
1495 memory_corruption_check_period parameters in
1496 Documentation/kernel-parameters.txt to adjust this.
1498 When enabled with the default parameters, this option has
1499 almost no overhead, as it reserves a relatively small amount
1500 of memory and scans it infrequently. It both detects corruption
1501 and prevents it from affecting the running system.
1503 It is, however, intended as a diagnostic tool; if repeatable
1504 BIOS-originated corruption always affects the same memory,
1505 you can use memmap= to prevent the kernel from using that
1508 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1509 bool "Set the default setting of memory_corruption_check"
1510 depends on X86_CHECK_BIOS_CORRUPTION
1513 Set whether the default state of memory_corruption_check is
1516 config X86_RESERVE_LOW
1517 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1521 Specify the amount of low memory to reserve for the BIOS.
1523 The first page contains BIOS data structures that the kernel
1524 must not use, so that page must always be reserved.
1526 By default we reserve the first 64K of physical RAM, as a
1527 number of BIOSes are known to corrupt that memory range
1528 during events such as suspend/resume or monitor cable
1529 insertion, so it must not be used by the kernel.
1531 You can set this to 4 if you are absolutely sure that you
1532 trust the BIOS to get all its memory reservations and usages
1533 right. If you know your BIOS have problems beyond the
1534 default 64K area, you can set this to 640 to avoid using the
1535 entire low memory range.
1537 If you have doubts about the BIOS (e.g. suspend/resume does
1538 not work or there's kernel crashes after certain hardware
1539 hotplug events) then you might want to enable
1540 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1541 typical corruption patterns.
1543 Leave this to the default value of 64 if you are unsure.
1545 config MATH_EMULATION
1547 depends on MODIFY_LDT_SYSCALL
1548 prompt "Math emulation" if X86_32
1550 Linux can emulate a math coprocessor (used for floating point
1551 operations) if you don't have one. 486DX and Pentium processors have
1552 a math coprocessor built in, 486SX and 386 do not, unless you added
1553 a 487DX or 387, respectively. (The messages during boot time can
1554 give you some hints here ["man dmesg"].) Everyone needs either a
1555 coprocessor or this emulation.
1557 If you don't have a math coprocessor, you need to say Y here; if you
1558 say Y here even though you have a coprocessor, the coprocessor will
1559 be used nevertheless. (This behavior can be changed with the kernel
1560 command line option "no387", which comes handy if your coprocessor
1561 is broken. Try "man bootparam" or see the documentation of your boot
1562 loader (lilo or loadlin) about how to pass options to the kernel at
1563 boot time.) This means that it is a good idea to say Y here if you
1564 intend to use this kernel on different machines.
1566 More information about the internals of the Linux math coprocessor
1567 emulation can be found in <file:arch/x86/math-emu/README>.
1569 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1570 kernel, it won't hurt.
1574 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1576 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1577 the Memory Type Range Registers (MTRRs) may be used to control
1578 processor access to memory ranges. This is most useful if you have
1579 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1580 allows bus write transfers to be combined into a larger transfer
1581 before bursting over the PCI/AGP bus. This can increase performance
1582 of image write operations 2.5 times or more. Saying Y here creates a
1583 /proc/mtrr file which may be used to manipulate your processor's
1584 MTRRs. Typically the X server should use this.
1586 This code has a reasonably generic interface so that similar
1587 control registers on other processors can be easily supported
1590 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1591 Registers (ARRs) which provide a similar functionality to MTRRs. For
1592 these, the ARRs are used to emulate the MTRRs.
1593 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1594 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1595 write-combining. All of these processors are supported by this code
1596 and it makes sense to say Y here if you have one of them.
1598 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1599 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1600 can lead to all sorts of problems, so it's good to say Y here.
1602 You can safely say Y even if your machine doesn't have MTRRs, you'll
1603 just add about 9 KB to your kernel.
1605 See <file:Documentation/x86/mtrr.txt> for more information.
1607 config MTRR_SANITIZER
1609 prompt "MTRR cleanup support"
1612 Convert MTRR layout from continuous to discrete, so X drivers can
1613 add writeback entries.
1615 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1616 The largest mtrr entry size for a continuous block can be set with
1621 config MTRR_SANITIZER_ENABLE_DEFAULT
1622 int "MTRR cleanup enable value (0-1)"
1625 depends on MTRR_SANITIZER
1627 Enable mtrr cleanup default value
1629 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1630 int "MTRR cleanup spare reg num (0-7)"
1633 depends on MTRR_SANITIZER
1635 mtrr cleanup spare entries default, it can be changed via
1636 mtrr_spare_reg_nr=N on the kernel command line.
1640 prompt "x86 PAT support" if EXPERT
1643 Use PAT attributes to setup page level cache control.
1645 PATs are the modern equivalents of MTRRs and are much more
1646 flexible than MTRRs.
1648 Say N here if you see bootup problems (boot crash, boot hang,
1649 spontaneous reboots) or a non-working video driver.
1653 config ARCH_USES_PG_UNCACHED
1659 prompt "x86 architectural random number generator" if EXPERT
1661 Enable the x86 architectural RDRAND instruction
1662 (Intel Bull Mountain technology) to generate random numbers.
1663 If supported, this is a high bandwidth, cryptographically
1664 secure hardware random number generator.
1668 prompt "Supervisor Mode Access Prevention" if EXPERT
1670 Supervisor Mode Access Prevention (SMAP) is a security
1671 feature in newer Intel processors. There is a small
1672 performance cost if this enabled and turned on; there is
1673 also a small increase in the kernel size if this is enabled.
1677 config X86_INTEL_MPX
1678 prompt "Intel MPX (Memory Protection Extensions)"
1680 depends on CPU_SUP_INTEL
1682 MPX provides hardware features that can be used in
1683 conjunction with compiler-instrumented code to check
1684 memory references. It is designed to detect buffer
1685 overflow or underflow bugs.
1687 This option enables running applications which are
1688 instrumented or otherwise use MPX. It does not use MPX
1689 itself inside the kernel or to protect the kernel
1690 against bad memory references.
1692 Enabling this option will make the kernel larger:
1693 ~8k of kernel text and 36 bytes of data on a 64-bit
1694 defconfig. It adds a long to the 'mm_struct' which
1695 will increase the kernel memory overhead of each
1696 process and adds some branches to paths used during
1697 exec() and munmap().
1699 For details, see Documentation/x86/intel_mpx.txt
1704 bool "EFI runtime service support"
1707 select EFI_RUNTIME_WRAPPERS
1709 This enables the kernel to use EFI runtime services that are
1710 available (such as the EFI variable services).
1712 This option is only useful on systems that have EFI firmware.
1713 In addition, you should use the latest ELILO loader available
1714 at <http://elilo.sourceforge.net> in order to take advantage
1715 of EFI runtime services. However, even with this option, the
1716 resultant kernel should continue to boot on existing non-EFI
1720 bool "EFI stub support"
1721 depends on EFI && !X86_USE_3DNOW
1724 This kernel feature allows a bzImage to be loaded directly
1725 by EFI firmware without the use of a bootloader.
1727 See Documentation/efi-stub.txt for more information.
1730 bool "EFI mixed-mode support"
1731 depends on EFI_STUB && X86_64
1733 Enabling this feature allows a 64-bit kernel to be booted
1734 on a 32-bit firmware, provided that your CPU supports 64-bit
1737 Note that it is not possible to boot a mixed-mode enabled
1738 kernel via the EFI boot stub - a bootloader that supports
1739 the EFI handover protocol must be used.
1745 prompt "Enable seccomp to safely compute untrusted bytecode"
1747 This kernel feature is useful for number crunching applications
1748 that may need to compute untrusted bytecode during their
1749 execution. By using pipes or other transports made available to
1750 the process as file descriptors supporting the read/write
1751 syscalls, it's possible to isolate those applications in
1752 their own address space using seccomp. Once seccomp is
1753 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1754 and the task is only allowed to execute a few safe syscalls
1755 defined by each seccomp mode.
1757 If unsure, say Y. Only embedded should say N here.
1759 source kernel/Kconfig.hz
1762 bool "kexec system call"
1765 kexec is a system call that implements the ability to shutdown your
1766 current kernel, and to start another kernel. It is like a reboot
1767 but it is independent of the system firmware. And like a reboot
1768 you can start any kernel with it, not just Linux.
1770 The name comes from the similarity to the exec system call.
1772 It is an ongoing process to be certain the hardware in a machine
1773 is properly shutdown, so do not be surprised if this code does not
1774 initially work for you. As of this writing the exact hardware
1775 interface is strongly in flux, so no good recommendation can be
1779 bool "kexec file based system call"
1784 depends on CRYPTO_SHA256=y
1786 This is new version of kexec system call. This system call is
1787 file based and takes file descriptors as system call argument
1788 for kernel and initramfs as opposed to list of segments as
1789 accepted by previous system call.
1791 config KEXEC_VERIFY_SIG
1792 bool "Verify kernel signature during kexec_file_load() syscall"
1793 depends on KEXEC_FILE
1795 This option makes kernel signature verification mandatory for
1796 the kexec_file_load() syscall.
1798 In addition to that option, you need to enable signature
1799 verification for the corresponding kernel image type being
1800 loaded in order for this to work.
1802 config KEXEC_BZIMAGE_VERIFY_SIG
1803 bool "Enable bzImage signature verification support"
1804 depends on KEXEC_VERIFY_SIG
1805 depends on SIGNED_PE_FILE_VERIFICATION
1806 select SYSTEM_TRUSTED_KEYRING
1808 Enable bzImage signature verification support.
1811 bool "kernel crash dumps"
1812 depends on X86_64 || (X86_32 && HIGHMEM)
1814 Generate crash dump after being started by kexec.
1815 This should be normally only set in special crash dump kernels
1816 which are loaded in the main kernel with kexec-tools into
1817 a specially reserved region and then later executed after
1818 a crash by kdump/kexec. The crash dump kernel must be compiled
1819 to a memory address not used by the main kernel or BIOS using
1820 PHYSICAL_START, or it must be built as a relocatable image
1821 (CONFIG_RELOCATABLE=y).
1822 For more details see Documentation/kdump/kdump.txt
1826 depends on KEXEC && HIBERNATION
1828 Jump between original kernel and kexeced kernel and invoke
1829 code in physical address mode via KEXEC
1831 config PHYSICAL_START
1832 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1835 This gives the physical address where the kernel is loaded.
1837 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1838 bzImage will decompress itself to above physical address and
1839 run from there. Otherwise, bzImage will run from the address where
1840 it has been loaded by the boot loader and will ignore above physical
1843 In normal kdump cases one does not have to set/change this option
1844 as now bzImage can be compiled as a completely relocatable image
1845 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1846 address. This option is mainly useful for the folks who don't want
1847 to use a bzImage for capturing the crash dump and want to use a
1848 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1849 to be specifically compiled to run from a specific memory area
1850 (normally a reserved region) and this option comes handy.
1852 So if you are using bzImage for capturing the crash dump,
1853 leave the value here unchanged to 0x1000000 and set
1854 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1855 for capturing the crash dump change this value to start of
1856 the reserved region. In other words, it can be set based on
1857 the "X" value as specified in the "crashkernel=YM@XM"
1858 command line boot parameter passed to the panic-ed
1859 kernel. Please take a look at Documentation/kdump/kdump.txt
1860 for more details about crash dumps.
1862 Usage of bzImage for capturing the crash dump is recommended as
1863 one does not have to build two kernels. Same kernel can be used
1864 as production kernel and capture kernel. Above option should have
1865 gone away after relocatable bzImage support is introduced. But it
1866 is present because there are users out there who continue to use
1867 vmlinux for dump capture. This option should go away down the
1870 Don't change this unless you know what you are doing.
1873 bool "Build a relocatable kernel"
1876 This builds a kernel image that retains relocation information
1877 so it can be loaded someplace besides the default 1MB.
1878 The relocations tend to make the kernel binary about 10% larger,
1879 but are discarded at runtime.
1881 One use is for the kexec on panic case where the recovery kernel
1882 must live at a different physical address than the primary
1885 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1886 it has been loaded at and the compile time physical address
1887 (CONFIG_PHYSICAL_START) is used as the minimum location.
1889 config RANDOMIZE_BASE
1890 bool "Randomize the address of the kernel image"
1891 depends on RELOCATABLE
1894 Randomizes the physical and virtual address at which the
1895 kernel image is decompressed, as a security feature that
1896 deters exploit attempts relying on knowledge of the location
1897 of kernel internals.
1899 Entropy is generated using the RDRAND instruction if it is
1900 supported. If RDTSC is supported, it is used as well. If
1901 neither RDRAND nor RDTSC are supported, then randomness is
1902 read from the i8254 timer.
1904 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1905 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1906 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1907 minimum of 2MiB, only 10 bits of entropy is theoretically
1908 possible. At best, due to page table layouts, 64-bit can use
1909 9 bits of entropy and 32-bit uses 8 bits.
1913 config RANDOMIZE_BASE_MAX_OFFSET
1914 hex "Maximum kASLR offset allowed" if EXPERT
1915 depends on RANDOMIZE_BASE
1916 range 0x0 0x20000000 if X86_32
1917 default "0x20000000" if X86_32
1918 range 0x0 0x40000000 if X86_64
1919 default "0x40000000" if X86_64
1921 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1922 memory is used to determine the maximal offset in bytes that will
1923 be applied to the kernel when kernel Address Space Layout
1924 Randomization (kASLR) is active. This must be a multiple of
1927 On 32-bit this is limited to 512MiB by page table layouts. The
1930 On 64-bit this is limited by how the kernel fixmap page table is
1931 positioned, so this cannot be larger than 1GiB currently. Without
1932 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1933 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1934 modules area will shrink to compensate, up to the current maximum
1935 1GiB to 1GiB split. The default is 1GiB.
1937 If unsure, leave at the default value.
1939 # Relocation on x86 needs some additional build support
1940 config X86_NEED_RELOCS
1942 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1944 config PHYSICAL_ALIGN
1945 hex "Alignment value to which kernel should be aligned"
1947 range 0x2000 0x1000000 if X86_32
1948 range 0x200000 0x1000000 if X86_64
1950 This value puts the alignment restrictions on physical address
1951 where kernel is loaded and run from. Kernel is compiled for an
1952 address which meets above alignment restriction.
1954 If bootloader loads the kernel at a non-aligned address and
1955 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1956 address aligned to above value and run from there.
1958 If bootloader loads the kernel at a non-aligned address and
1959 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1960 load address and decompress itself to the address it has been
1961 compiled for and run from there. The address for which kernel is
1962 compiled already meets above alignment restrictions. Hence the
1963 end result is that kernel runs from a physical address meeting
1964 above alignment restrictions.
1966 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1967 this value must be a multiple of 0x200000.
1969 Don't change this unless you know what you are doing.
1972 bool "Support for hot-pluggable CPUs"
1975 Say Y here to allow turning CPUs off and on. CPUs can be
1976 controlled through /sys/devices/system/cpu.
1977 ( Note: power management support will enable this option
1978 automatically on SMP systems. )
1979 Say N if you want to disable CPU hotplug.
1981 config BOOTPARAM_HOTPLUG_CPU0
1982 bool "Set default setting of cpu0_hotpluggable"
1984 depends on HOTPLUG_CPU
1986 Set whether default state of cpu0_hotpluggable is on or off.
1988 Say Y here to enable CPU0 hotplug by default. If this switch
1989 is turned on, there is no need to give cpu0_hotplug kernel
1990 parameter and the CPU0 hotplug feature is enabled by default.
1992 Please note: there are two known CPU0 dependencies if you want
1993 to enable the CPU0 hotplug feature either by this switch or by
1994 cpu0_hotplug kernel parameter.
1996 First, resume from hibernate or suspend always starts from CPU0.
1997 So hibernate and suspend are prevented if CPU0 is offline.
1999 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2000 offline if any interrupt can not migrate out of CPU0. There may
2001 be other CPU0 dependencies.
2003 Please make sure the dependencies are under your control before
2004 you enable this feature.
2006 Say N if you don't want to enable CPU0 hotplug feature by default.
2007 You still can enable the CPU0 hotplug feature at boot by kernel
2008 parameter cpu0_hotplug.
2010 config DEBUG_HOTPLUG_CPU0
2012 prompt "Debug CPU0 hotplug"
2013 depends on HOTPLUG_CPU
2015 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2016 soon as possible and boots up userspace with CPU0 offlined. User
2017 can online CPU0 back after boot time.
2019 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2020 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2021 compilation or giving cpu0_hotplug kernel parameter at boot.
2027 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2028 depends on X86_32 || IA32_EMULATION
2030 Certain buggy versions of glibc will crash if they are
2031 presented with a 32-bit vDSO that is not mapped at the address
2032 indicated in its segment table.
2034 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2035 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2036 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2037 the only released version with the bug, but OpenSUSE 9
2038 contains a buggy "glibc 2.3.2".
2040 The symptom of the bug is that everything crashes on startup, saying:
2041 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2043 Saying Y here changes the default value of the vdso32 boot
2044 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2045 This works around the glibc bug but hurts performance.
2047 If unsure, say N: if you are compiling your own kernel, you
2048 are unlikely to be using a buggy version of glibc.
2051 prompt "vsyscall table for legacy applications"
2053 default LEGACY_VSYSCALL_EMULATE
2055 Legacy user code that does not know how to find the vDSO expects
2056 to be able to issue three syscalls by calling fixed addresses in
2057 kernel space. Since this location is not randomized with ASLR,
2058 it can be used to assist security vulnerability exploitation.
2060 This setting can be changed at boot time via the kernel command
2061 line parameter vsyscall=[native|emulate|none].
2063 On a system with recent enough glibc (2.14 or newer) and no
2064 static binaries, you can say None without a performance penalty
2065 to improve security.
2067 If unsure, select "Emulate".
2069 config LEGACY_VSYSCALL_NATIVE
2072 Actual executable code is located in the fixed vsyscall
2073 address mapping, implementing time() efficiently. Since
2074 this makes the mapping executable, it can be used during
2075 security vulnerability exploitation (traditionally as
2076 ROP gadgets). This configuration is not recommended.
2078 config LEGACY_VSYSCALL_EMULATE
2081 The kernel traps and emulates calls into the fixed
2082 vsyscall address mapping. This makes the mapping
2083 non-executable, but it still contains known contents,
2084 which could be used in certain rare security vulnerability
2085 exploits. This configuration is recommended when userspace
2086 still uses the vsyscall area.
2088 config LEGACY_VSYSCALL_NONE
2091 There will be no vsyscall mapping at all. This will
2092 eliminate any risk of ASLR bypass due to the vsyscall
2093 fixed address mapping. Attempts to use the vsyscalls
2094 will be reported to dmesg, so that either old or
2095 malicious userspace programs can be identified.
2100 bool "Built-in kernel command line"
2102 Allow for specifying boot arguments to the kernel at
2103 build time. On some systems (e.g. embedded ones), it is
2104 necessary or convenient to provide some or all of the
2105 kernel boot arguments with the kernel itself (that is,
2106 to not rely on the boot loader to provide them.)
2108 To compile command line arguments into the kernel,
2109 set this option to 'Y', then fill in the
2110 boot arguments in CONFIG_CMDLINE.
2112 Systems with fully functional boot loaders (i.e. non-embedded)
2113 should leave this option set to 'N'.
2116 string "Built-in kernel command string"
2117 depends on CMDLINE_BOOL
2120 Enter arguments here that should be compiled into the kernel
2121 image and used at boot time. If the boot loader provides a
2122 command line at boot time, it is appended to this string to
2123 form the full kernel command line, when the system boots.
2125 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2126 change this behavior.
2128 In most cases, the command line (whether built-in or provided
2129 by the boot loader) should specify the device for the root
2132 config CMDLINE_OVERRIDE
2133 bool "Built-in command line overrides boot loader arguments"
2134 depends on CMDLINE_BOOL
2136 Set this option to 'Y' to have the kernel ignore the boot loader
2137 command line, and use ONLY the built-in command line.
2139 This is used to work around broken boot loaders. This should
2140 be set to 'N' under normal conditions.
2142 config MODIFY_LDT_SYSCALL
2143 bool "Enable the LDT (local descriptor table)" if EXPERT
2146 Linux can allow user programs to install a per-process x86
2147 Local Descriptor Table (LDT) using the modify_ldt(2) system
2148 call. This is required to run 16-bit or segmented code such as
2149 DOSEMU or some Wine programs. It is also used by some very old
2150 threading libraries.
2152 Enabling this feature adds a small amount of overhead to
2153 context switches and increases the low-level kernel attack
2154 surface. Disabling it removes the modify_ldt(2) system call.
2156 Saying 'N' here may make sense for embedded or server kernels.
2158 source "kernel/livepatch/Kconfig"
2162 config ARCH_ENABLE_MEMORY_HOTPLUG
2164 depends on X86_64 || (X86_32 && HIGHMEM)
2166 config ARCH_ENABLE_MEMORY_HOTREMOVE
2168 depends on MEMORY_HOTPLUG
2170 config USE_PERCPU_NUMA_NODE_ID
2174 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2176 depends on X86_64 || X86_PAE
2178 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2180 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2182 menu "Power management and ACPI options"
2184 config ARCH_HIBERNATION_HEADER
2186 depends on X86_64 && HIBERNATION
2188 source "kernel/power/Kconfig"
2190 source "drivers/acpi/Kconfig"
2192 source "drivers/sfi/Kconfig"
2199 tristate "APM (Advanced Power Management) BIOS support"
2200 depends on X86_32 && PM_SLEEP
2202 APM is a BIOS specification for saving power using several different
2203 techniques. This is mostly useful for battery powered laptops with
2204 APM compliant BIOSes. If you say Y here, the system time will be
2205 reset after a RESUME operation, the /proc/apm device will provide
2206 battery status information, and user-space programs will receive
2207 notification of APM "events" (e.g. battery status change).
2209 If you select "Y" here, you can disable actual use of the APM
2210 BIOS by passing the "apm=off" option to the kernel at boot time.
2212 Note that the APM support is almost completely disabled for
2213 machines with more than one CPU.
2215 In order to use APM, you will need supporting software. For location
2216 and more information, read <file:Documentation/power/apm-acpi.txt>
2217 and the Battery Powered Linux mini-HOWTO, available from
2218 <http://www.tldp.org/docs.html#howto>.
2220 This driver does not spin down disk drives (see the hdparm(8)
2221 manpage ("man 8 hdparm") for that), and it doesn't turn off
2222 VESA-compliant "green" monitors.
2224 This driver does not support the TI 4000M TravelMate and the ACER
2225 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2226 desktop machines also don't have compliant BIOSes, and this driver
2227 may cause those machines to panic during the boot phase.
2229 Generally, if you don't have a battery in your machine, there isn't
2230 much point in using this driver and you should say N. If you get
2231 random kernel OOPSes or reboots that don't seem to be related to
2232 anything, try disabling/enabling this option (or disabling/enabling
2235 Some other things you should try when experiencing seemingly random,
2238 1) make sure that you have enough swap space and that it is
2240 2) pass the "no-hlt" option to the kernel
2241 3) switch on floating point emulation in the kernel and pass
2242 the "no387" option to the kernel
2243 4) pass the "floppy=nodma" option to the kernel
2244 5) pass the "mem=4M" option to the kernel (thereby disabling
2245 all but the first 4 MB of RAM)
2246 6) make sure that the CPU is not over clocked.
2247 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2248 8) disable the cache from your BIOS settings
2249 9) install a fan for the video card or exchange video RAM
2250 10) install a better fan for the CPU
2251 11) exchange RAM chips
2252 12) exchange the motherboard.
2254 To compile this driver as a module, choose M here: the
2255 module will be called apm.
2259 config APM_IGNORE_USER_SUSPEND
2260 bool "Ignore USER SUSPEND"
2262 This option will ignore USER SUSPEND requests. On machines with a
2263 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2264 series notebooks, it is necessary to say Y because of a BIOS bug.
2266 config APM_DO_ENABLE
2267 bool "Enable PM at boot time"
2269 Enable APM features at boot time. From page 36 of the APM BIOS
2270 specification: "When disabled, the APM BIOS does not automatically
2271 power manage devices, enter the Standby State, enter the Suspend
2272 State, or take power saving steps in response to CPU Idle calls."
2273 This driver will make CPU Idle calls when Linux is idle (unless this
2274 feature is turned off -- see "Do CPU IDLE calls", below). This
2275 should always save battery power, but more complicated APM features
2276 will be dependent on your BIOS implementation. You may need to turn
2277 this option off if your computer hangs at boot time when using APM
2278 support, or if it beeps continuously instead of suspending. Turn
2279 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2280 T400CDT. This is off by default since most machines do fine without
2285 bool "Make CPU Idle calls when idle"
2287 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2288 On some machines, this can activate improved power savings, such as
2289 a slowed CPU clock rate, when the machine is idle. These idle calls
2290 are made after the idle loop has run for some length of time (e.g.,
2291 333 mS). On some machines, this will cause a hang at boot time or
2292 whenever the CPU becomes idle. (On machines with more than one CPU,
2293 this option does nothing.)
2295 config APM_DISPLAY_BLANK
2296 bool "Enable console blanking using APM"
2298 Enable console blanking using the APM. Some laptops can use this to
2299 turn off the LCD backlight when the screen blanker of the Linux
2300 virtual console blanks the screen. Note that this is only used by
2301 the virtual console screen blanker, and won't turn off the backlight
2302 when using the X Window system. This also doesn't have anything to
2303 do with your VESA-compliant power-saving monitor. Further, this
2304 option doesn't work for all laptops -- it might not turn off your
2305 backlight at all, or it might print a lot of errors to the console,
2306 especially if you are using gpm.
2308 config APM_ALLOW_INTS
2309 bool "Allow interrupts during APM BIOS calls"
2311 Normally we disable external interrupts while we are making calls to
2312 the APM BIOS as a measure to lessen the effects of a badly behaving
2313 BIOS implementation. The BIOS should reenable interrupts if it
2314 needs to. Unfortunately, some BIOSes do not -- especially those in
2315 many of the newer IBM Thinkpads. If you experience hangs when you
2316 suspend, try setting this to Y. Otherwise, say N.
2320 source "drivers/cpufreq/Kconfig"
2322 source "drivers/cpuidle/Kconfig"
2324 source "drivers/idle/Kconfig"
2329 menu "Bus options (PCI etc.)"
2335 Find out whether you have a PCI motherboard. PCI is the name of a
2336 bus system, i.e. the way the CPU talks to the other stuff inside
2337 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2338 VESA. If you have PCI, say Y, otherwise N.
2341 prompt "PCI access mode"
2342 depends on X86_32 && PCI
2345 On PCI systems, the BIOS can be used to detect the PCI devices and
2346 determine their configuration. However, some old PCI motherboards
2347 have BIOS bugs and may crash if this is done. Also, some embedded
2348 PCI-based systems don't have any BIOS at all. Linux can also try to
2349 detect the PCI hardware directly without using the BIOS.
2351 With this option, you can specify how Linux should detect the
2352 PCI devices. If you choose "BIOS", the BIOS will be used,
2353 if you choose "Direct", the BIOS won't be used, and if you
2354 choose "MMConfig", then PCI Express MMCONFIG will be used.
2355 If you choose "Any", the kernel will try MMCONFIG, then the
2356 direct access method and falls back to the BIOS if that doesn't
2357 work. If unsure, go with the default, which is "Any".
2362 config PCI_GOMMCONFIG
2379 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2381 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2384 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2388 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2392 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2396 depends on PCI && XEN
2404 bool "Support mmconfig PCI config space access"
2405 depends on X86_64 && PCI && ACPI
2407 config PCI_CNB20LE_QUIRK
2408 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2411 Read the PCI windows out of the CNB20LE host bridge. This allows
2412 PCI hotplug to work on systems with the CNB20LE chipset which do
2415 There's no public spec for this chipset, and this functionality
2416 is known to be incomplete.
2418 You should say N unless you know you need this.
2420 source "drivers/pci/pcie/Kconfig"
2422 source "drivers/pci/Kconfig"
2424 # x86_64 have no ISA slots, but can have ISA-style DMA.
2426 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2429 Enables ISA-style DMA support for devices requiring such controllers.
2437 Find out whether you have ISA slots on your motherboard. ISA is the
2438 name of a bus system, i.e. the way the CPU talks to the other stuff
2439 inside your box. Other bus systems are PCI, EISA, MicroChannel
2440 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2441 newer boards don't support it. If you have ISA, say Y, otherwise N.
2447 The Extended Industry Standard Architecture (EISA) bus was
2448 developed as an open alternative to the IBM MicroChannel bus.
2450 The EISA bus provided some of the features of the IBM MicroChannel
2451 bus while maintaining backward compatibility with cards made for
2452 the older ISA bus. The EISA bus saw limited use between 1988 and
2453 1995 when it was made obsolete by the PCI bus.
2455 Say Y here if you are building a kernel for an EISA-based machine.
2459 source "drivers/eisa/Kconfig"
2462 tristate "NatSemi SCx200 support"
2464 This provides basic support for National Semiconductor's
2465 (now AMD's) Geode processors. The driver probes for the
2466 PCI-IDs of several on-chip devices, so its a good dependency
2467 for other scx200_* drivers.
2469 If compiled as a module, the driver is named scx200.
2471 config SCx200HR_TIMER
2472 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2476 This driver provides a clocksource built upon the on-chip
2477 27MHz high-resolution timer. Its also a workaround for
2478 NSC Geode SC-1100's buggy TSC, which loses time when the
2479 processor goes idle (as is done by the scheduler). The
2480 other workaround is idle=poll boot option.
2483 bool "One Laptop Per Child support"
2490 Add support for detecting the unique features of the OLPC
2494 bool "OLPC XO-1 Power Management"
2495 depends on OLPC && MFD_CS5535 && PM_SLEEP
2498 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2501 bool "OLPC XO-1 Real Time Clock"
2502 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2504 Add support for the XO-1 real time clock, which can be used as a
2505 programmable wakeup source.
2508 bool "OLPC XO-1 SCI extras"
2509 depends on OLPC && OLPC_XO1_PM
2515 Add support for SCI-based features of the OLPC XO-1 laptop:
2516 - EC-driven system wakeups
2520 - AC adapter status updates
2521 - Battery status updates
2523 config OLPC_XO15_SCI
2524 bool "OLPC XO-1.5 SCI extras"
2525 depends on OLPC && ACPI
2528 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2529 - EC-driven system wakeups
2530 - AC adapter status updates
2531 - Battery status updates
2534 bool "PCEngines ALIX System Support (LED setup)"
2537 This option enables system support for the PCEngines ALIX.
2538 At present this just sets up LEDs for GPIO control on
2539 ALIX2/3/6 boards. However, other system specific setup should
2542 Note: You must still enable the drivers for GPIO and LED support
2543 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2545 Note: You have to set alix.force=1 for boards with Award BIOS.
2548 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2551 This option enables system support for the Soekris Engineering net5501.
2554 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2558 This option enables system support for the Traverse Technologies GEOS.
2561 bool "Technologic Systems TS-5500 platform support"
2563 select CHECK_SIGNATURE
2567 This option enables system support for the Technologic Systems TS-5500.
2573 depends on CPU_SUP_AMD && PCI
2575 source "drivers/pcmcia/Kconfig"
2577 source "drivers/pci/hotplug/Kconfig"
2580 tristate "RapidIO support"
2584 If enabled this option will include drivers and the core
2585 infrastructure code to support RapidIO interconnect devices.
2587 source "drivers/rapidio/Kconfig"
2590 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2592 Firmwares often provide initial graphics framebuffers so the BIOS,
2593 bootloader or kernel can show basic video-output during boot for
2594 user-guidance and debugging. Historically, x86 used the VESA BIOS
2595 Extensions and EFI-framebuffers for this, which are mostly limited
2597 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2598 framebuffers so the new generic system-framebuffer drivers can be
2599 used on x86. If the framebuffer is not compatible with the generic
2600 modes, it is adverticed as fallback platform framebuffer so legacy
2601 drivers like efifb, vesafb and uvesafb can pick it up.
2602 If this option is not selected, all system framebuffers are always
2603 marked as fallback platform framebuffers as usual.
2605 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2606 not be able to pick up generic system framebuffers if this option
2607 is selected. You are highly encouraged to enable simplefb as
2608 replacement if you select this option. simplefb can correctly deal
2609 with generic system framebuffers. But you should still keep vesafb
2610 and others enabled as fallback if a system framebuffer is
2611 incompatible with simplefb.
2618 menu "Executable file formats / Emulations"
2620 source "fs/Kconfig.binfmt"
2622 config IA32_EMULATION
2623 bool "IA32 Emulation"
2626 select COMPAT_BINFMT_ELF
2627 select ARCH_WANT_OLD_COMPAT_IPC
2629 Include code to run legacy 32-bit programs under a
2630 64-bit kernel. You should likely turn this on, unless you're
2631 100% sure that you don't have any 32-bit programs left.
2634 tristate "IA32 a.out support"
2635 depends on IA32_EMULATION
2637 Support old a.out binaries in the 32bit emulation.
2640 bool "x32 ABI for 64-bit mode"
2643 Include code to run binaries for the x32 native 32-bit ABI
2644 for 64-bit processors. An x32 process gets access to the
2645 full 64-bit register file and wide data path while leaving
2646 pointers at 32 bits for smaller memory footprint.
2648 You will need a recent binutils (2.22 or later) with
2649 elf32_x86_64 support enabled to compile a kernel with this
2654 depends on IA32_EMULATION || X86_X32
2657 config COMPAT_FOR_U64_ALIGNMENT
2660 config SYSVIPC_COMPAT
2672 config HAVE_ATOMIC_IOMAP
2676 config X86_DEV_DMA_OPS
2678 depends on X86_64 || STA2X11
2680 config X86_DMA_REMAP
2688 source "net/Kconfig"
2690 source "drivers/Kconfig"
2692 source "drivers/firmware/Kconfig"
2696 source "arch/x86/Kconfig.debug"
2698 source "security/Kconfig"
2700 source "crypto/Kconfig"
2702 source "arch/x86/kvm/Kconfig"
2704 source "lib/Kconfig"