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_ACPI_TABLE_UPGRADE if ACPI
26 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
27 select ARCH_HAS_DEVMEM_IS_ALLOWED
28 select ARCH_HAS_ELF_RANDOMIZE
29 select ARCH_HAS_FAST_MULTIPLIER
30 select ARCH_HAS_GCOV_PROFILE_ALL
31 select ARCH_HAS_GIGANTIC_PAGE if X86_64
32 select ARCH_HAS_KCOV if X86_64
33 select ARCH_HAS_PMEM_API if X86_64
34 select ARCH_HAS_MMIO_FLUSH
35 select ARCH_HAS_SG_CHAIN
36 select ARCH_HAS_UBSAN_SANITIZE_ALL
37 select ARCH_HAVE_NMI_SAFE_CMPXCHG
38 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
39 select ARCH_MIGHT_HAVE_PC_PARPORT
40 select ARCH_MIGHT_HAVE_PC_SERIO
41 select ARCH_SUPPORTS_ATOMIC_RMW
42 select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
43 select ARCH_SUPPORTS_INT128 if X86_64
44 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
45 select ARCH_USE_BUILTIN_BSWAP
46 select ARCH_USE_CMPXCHG_LOCKREF if X86_64
47 select ARCH_USE_QUEUED_RWLOCKS
48 select ARCH_USE_QUEUED_SPINLOCKS
49 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if SMP
50 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
51 select ARCH_WANT_FRAME_POINTERS
52 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
53 select BUILDTIME_EXTABLE_SORT
55 select CLKSRC_I8253 if X86_32
56 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
57 select CLOCKSOURCE_WATCHDOG
58 select CLONE_BACKWARDS if X86_32
59 select COMPAT_OLD_SIGACTION if IA32_EMULATION
60 select DCACHE_WORD_ACCESS
61 select EDAC_ATOMIC_SCRUB
63 select GENERIC_CLOCKEVENTS
64 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
65 select GENERIC_CLOCKEVENTS_MIN_ADJUST
66 select GENERIC_CMOS_UPDATE
67 select GENERIC_CPU_AUTOPROBE
68 select GENERIC_EARLY_IOREMAP
69 select GENERIC_FIND_FIRST_BIT
71 select GENERIC_IRQ_PROBE
72 select GENERIC_IRQ_SHOW
73 select GENERIC_PENDING_IRQ if SMP
74 select GENERIC_SMP_IDLE_THREAD
75 select GENERIC_STRNCPY_FROM_USER
76 select GENERIC_STRNLEN_USER
77 select GENERIC_TIME_VSYSCALL
78 select HAVE_ACPI_APEI if ACPI
79 select HAVE_ACPI_APEI_NMI if ACPI
80 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
81 select HAVE_AOUT if X86_32
82 select HAVE_ARCH_AUDITSYSCALL
83 select HAVE_ARCH_HARDENED_USERCOPY
84 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
85 select HAVE_ARCH_JUMP_LABEL
86 select HAVE_ARCH_KASAN if X86_64 && SPARSEMEM_VMEMMAP
88 select HAVE_ARCH_KMEMCHECK
89 select HAVE_ARCH_MMAP_RND_BITS if MMU
90 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
91 select HAVE_ARCH_SECCOMP_FILTER
92 select HAVE_ARCH_SOFT_DIRTY if X86_64
93 select HAVE_ARCH_TRACEHOOK
94 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
95 select HAVE_ARCH_WITHIN_STACK_FRAMES
96 select HAVE_EBPF_JIT if X86_64
97 select HAVE_ARCH_VMAP_STACK if X86_64
98 select HAVE_CC_STACKPROTECTOR
99 select HAVE_CMPXCHG_DOUBLE
100 select HAVE_CMPXCHG_LOCAL
101 select HAVE_CONTEXT_TRACKING if X86_64
102 select HAVE_COPY_THREAD_TLS
103 select HAVE_C_RECORDMCOUNT
104 select HAVE_DEBUG_KMEMLEAK
105 select HAVE_DEBUG_STACKOVERFLOW
106 select HAVE_DMA_API_DEBUG
107 select HAVE_DMA_CONTIGUOUS
108 select HAVE_DYNAMIC_FTRACE
109 select HAVE_DYNAMIC_FTRACE_WITH_REGS
110 select HAVE_EFFICIENT_UNALIGNED_ACCESS
111 select HAVE_EXIT_THREAD
112 select HAVE_FENTRY if X86_64
113 select HAVE_FTRACE_MCOUNT_RECORD
114 select HAVE_FUNCTION_GRAPH_TRACER
115 select HAVE_FUNCTION_TRACER
116 select HAVE_GCC_PLUGINS
117 select HAVE_GENERIC_DMA_COHERENT if X86_32
118 select HAVE_HW_BREAKPOINT
120 select HAVE_IOREMAP_PROT
121 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
122 select HAVE_IRQ_TIME_ACCOUNTING
123 select HAVE_KERNEL_BZIP2
124 select HAVE_KERNEL_GZIP
125 select HAVE_KERNEL_LZ4
126 select HAVE_KERNEL_LZMA
127 select HAVE_KERNEL_LZO
128 select HAVE_KERNEL_XZ
130 select HAVE_KPROBES_ON_FTRACE
131 select HAVE_KRETPROBES
133 select HAVE_LIVEPATCH if X86_64
135 select HAVE_MEMBLOCK_NODE_MAP
136 select HAVE_MIXED_BREAKPOINTS_REGS
139 select HAVE_OPTPROBES
140 select HAVE_PCSPKR_PLATFORM
141 select HAVE_PERF_EVENTS
142 select HAVE_PERF_EVENTS_NMI
143 select HAVE_PERF_REGS
144 select HAVE_PERF_USER_STACK_DUMP
145 select HAVE_REGS_AND_STACK_ACCESS_API
146 select HAVE_SYSCALL_TRACEPOINTS
147 select HAVE_UID16 if X86_32 || IA32_EMULATION
148 select HAVE_UNSTABLE_SCHED_CLOCK
149 select HAVE_USER_RETURN_NOTIFIER
150 select IRQ_FORCED_THREADING
151 select MODULES_USE_ELF_RELA if X86_64
152 select MODULES_USE_ELF_REL if X86_32
153 select OLD_SIGACTION if X86_32
154 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
157 select RTC_MC146818_LIB
160 select SYSCTL_EXCEPTION_TRACE
161 select THREAD_INFO_IN_TASK
162 select USER_STACKTRACE_SUPPORT
164 select X86_DEV_DMA_OPS if X86_64
165 select X86_FEATURE_NAMES if PROC_FS
166 select HAVE_STACK_VALIDATION if X86_64
167 select ARCH_USES_HIGH_VMA_FLAGS if X86_INTEL_MEMORY_PROTECTION_KEYS
168 select ARCH_HAS_PKEYS if X86_INTEL_MEMORY_PROTECTION_KEYS
170 config INSTRUCTION_DECODER
172 depends on KPROBES || PERF_EVENTS || UPROBES
176 default "elf32-i386" if X86_32
177 default "elf64-x86-64" if X86_64
179 config ARCH_DEFCONFIG
181 default "arch/x86/configs/i386_defconfig" if X86_32
182 default "arch/x86/configs/x86_64_defconfig" if X86_64
184 config LOCKDEP_SUPPORT
187 config STACKTRACE_SUPPORT
193 config ARCH_MMAP_RND_BITS_MIN
197 config ARCH_MMAP_RND_BITS_MAX
201 config ARCH_MMAP_RND_COMPAT_BITS_MIN
204 config ARCH_MMAP_RND_COMPAT_BITS_MAX
210 config NEED_DMA_MAP_STATE
212 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
214 config NEED_SG_DMA_LENGTH
217 config GENERIC_ISA_DMA
219 depends on ISA_DMA_API
224 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
226 config GENERIC_BUG_RELATIVE_POINTERS
229 config GENERIC_HWEIGHT
232 config ARCH_MAY_HAVE_PC_FDC
234 depends on ISA_DMA_API
236 config RWSEM_XCHGADD_ALGORITHM
239 config GENERIC_CALIBRATE_DELAY
242 config ARCH_HAS_CPU_RELAX
245 config ARCH_HAS_CACHE_LINE_SIZE
248 config HAVE_SETUP_PER_CPU_AREA
251 config NEED_PER_CPU_EMBED_FIRST_CHUNK
254 config NEED_PER_CPU_PAGE_FIRST_CHUNK
257 config ARCH_HIBERNATION_POSSIBLE
260 config ARCH_SUSPEND_POSSIBLE
263 config ARCH_WANT_HUGE_PMD_SHARE
266 config ARCH_WANT_GENERAL_HUGETLB
275 config ARCH_SUPPORTS_OPTIMIZED_INLINING
278 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
281 config KASAN_SHADOW_OFFSET
284 default 0xdffffc0000000000
286 config HAVE_INTEL_TXT
288 depends on INTEL_IOMMU && ACPI
292 depends on X86_32 && SMP
296 depends on X86_64 && SMP
298 config X86_32_LAZY_GS
300 depends on X86_32 && !CC_STACKPROTECTOR
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.
371 config X86_FAST_FEATURE_TESTS
372 bool "Fast CPU feature tests" if EMBEDDED
375 Some fast-paths in the kernel depend on the capabilities of the CPU.
376 Say Y here for the kernel to patch in the appropriate code at runtime
377 based on the capabilities of the CPU. The infrastructure for patching
378 code at runtime takes up some additional space; space-constrained
379 embedded systems may wish to say N here to produce smaller, slightly
383 bool "Support x2apic"
384 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
386 This enables x2apic support on CPUs that have this feature.
388 This allows 32-bit apic IDs (so it can support very large systems),
389 and accesses the local apic via MSRs not via mmio.
391 If you don't know what to do here, say N.
394 bool "Enable MPS table" if ACPI || SFI
396 depends on X86_LOCAL_APIC
398 For old smp systems that do not have proper acpi support. Newer systems
399 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
402 bool "Support for big SMP systems with more than 8 CPUs"
403 depends on X86_32 && SMP
405 This option is needed for the systems that have more than 8 CPUs
409 depends on X86_GOLDFISH
412 config X86_EXTENDED_PLATFORM
413 bool "Support for extended (non-PC) x86 platforms"
416 If you disable this option then the kernel will only support
417 standard PC platforms. (which covers the vast majority of
420 If you enable this option then you'll be able to select support
421 for the following (non-PC) 32 bit x86 platforms:
422 Goldfish (Android emulator)
425 SGI 320/540 (Visual Workstation)
426 STA2X11-based (e.g. Northville)
427 Moorestown MID devices
429 If you have one of these systems, or if you want to build a
430 generic distribution kernel, say Y here - otherwise say N.
434 config X86_EXTENDED_PLATFORM
435 bool "Support for extended (non-PC) x86 platforms"
438 If you disable this option then the kernel will only support
439 standard PC platforms. (which covers the vast majority of
442 If you enable this option then you'll be able to select support
443 for the following (non-PC) 64 bit x86 platforms:
448 If you have one of these systems, or if you want to build a
449 generic distribution kernel, say Y here - otherwise say N.
451 # This is an alphabetically sorted list of 64 bit extended platforms
452 # Please maintain the alphabetic order if and when there are additions
454 bool "Numascale NumaChip"
456 depends on X86_EXTENDED_PLATFORM
459 depends on X86_X2APIC
460 depends on PCI_MMCONFIG
462 Adds support for Numascale NumaChip large-SMP systems. Needed to
463 enable more than ~168 cores.
464 If you don't have one of these, you should say N here.
468 select HYPERVISOR_GUEST
470 depends on X86_64 && PCI
471 depends on X86_EXTENDED_PLATFORM
474 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
475 supposed to run on these EM64T-based machines. Only choose this option
476 if you have one of these machines.
479 bool "SGI Ultraviolet"
481 depends on X86_EXTENDED_PLATFORM
484 depends on X86_X2APIC
487 This option is needed in order to support SGI Ultraviolet systems.
488 If you don't have one of these, you should say N here.
490 # Following is an alphabetically sorted list of 32 bit extended platforms
491 # Please maintain the alphabetic order if and when there are additions
494 bool "Goldfish (Virtual Platform)"
495 depends on X86_EXTENDED_PLATFORM
497 Enable support for the Goldfish virtual platform used primarily
498 for Android development. Unless you are building for the Android
499 Goldfish emulator say N here.
502 bool "CE4100 TV platform"
504 depends on PCI_GODIRECT
505 depends on X86_IO_APIC
507 depends on X86_EXTENDED_PLATFORM
508 select X86_REBOOTFIXUPS
510 select OF_EARLY_FLATTREE
512 Select for the Intel CE media processor (CE4100) SOC.
513 This option compiles in support for the CE4100 SOC for settop
514 boxes and media devices.
517 bool "Intel MID platform support"
518 depends on X86_EXTENDED_PLATFORM
519 depends on X86_PLATFORM_DEVICES
521 depends on X86_64 || (PCI_GOANY && X86_32)
522 depends on X86_IO_APIC
528 select MFD_INTEL_MSIC
530 Select to build a kernel capable of supporting Intel MID (Mobile
531 Internet Device) platform systems which do not have the PCI legacy
532 interfaces. If you are building for a PC class system say N here.
534 Intel MID platforms are based on an Intel processor and chipset which
535 consume less power than most of the x86 derivatives.
537 config X86_INTEL_QUARK
538 bool "Intel Quark platform support"
540 depends on X86_EXTENDED_PLATFORM
541 depends on X86_PLATFORM_DEVICES
545 depends on X86_IO_APIC
550 Select to include support for Quark X1000 SoC.
551 Say Y here if you have a Quark based system such as the Arduino
552 compatible Intel Galileo.
555 tristate "Mellanox Technologies platform support"
557 depends on X86_EXTENDED_PLATFORM
559 This option enables system support for the Mellanox Technologies
562 Say Y here if you are building a kernel for Mellanox system.
566 config X86_INTEL_LPSS
567 bool "Intel Low Power Subsystem Support"
568 depends on X86 && ACPI
573 Select to build support for Intel Low Power Subsystem such as
574 found on Intel Lynxpoint PCH. Selecting this option enables
575 things like clock tree (common clock framework) and pincontrol
576 which are needed by the LPSS peripheral drivers.
578 config X86_AMD_PLATFORM_DEVICE
579 bool "AMD ACPI2Platform devices support"
584 Select to interpret AMD specific ACPI device to platform device
585 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
586 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
587 implemented under PINCTRL subsystem.
590 tristate "Intel SoC IOSF Sideband support for SoC platforms"
593 This option enables sideband register access support for Intel SoC
594 platforms. On these platforms the IOSF sideband is used in lieu of
595 MSR's for some register accesses, mostly but not limited to thermal
596 and power. Drivers may query the availability of this device to
597 determine if they need the sideband in order to work on these
598 platforms. The sideband is available on the following SoC products.
599 This list is not meant to be exclusive.
604 You should say Y if you are running a kernel on one of these SoC's.
606 config IOSF_MBI_DEBUG
607 bool "Enable IOSF sideband access through debugfs"
608 depends on IOSF_MBI && DEBUG_FS
610 Select this option to expose the IOSF sideband access registers (MCR,
611 MDR, MCRX) through debugfs to write and read register information from
612 different units on the SoC. This is most useful for obtaining device
613 state information for debug and analysis. As this is a general access
614 mechanism, users of this option would have specific knowledge of the
615 device they want to access.
617 If you don't require the option or are in doubt, say N.
620 bool "RDC R-321x SoC"
622 depends on X86_EXTENDED_PLATFORM
624 select X86_REBOOTFIXUPS
626 This option is needed for RDC R-321x system-on-chip, also known
628 If you don't have one of these chips, you should say N here.
630 config X86_32_NON_STANDARD
631 bool "Support non-standard 32-bit SMP architectures"
632 depends on X86_32 && SMP
633 depends on X86_EXTENDED_PLATFORM
635 This option compiles in the bigsmp and STA2X11 default
636 subarchitectures. It is intended for a generic binary
637 kernel. If you select them all, kernel will probe it one by
638 one and will fallback to default.
640 # Alphabetically sorted list of Non standard 32 bit platforms
642 config X86_SUPPORTS_MEMORY_FAILURE
644 # MCE code calls memory_failure():
646 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
647 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
648 depends on X86_64 || !SPARSEMEM
649 select ARCH_SUPPORTS_MEMORY_FAILURE
652 bool "STA2X11 Companion Chip Support"
653 depends on X86_32_NON_STANDARD && PCI
654 select X86_DEV_DMA_OPS
661 This adds support for boards based on the STA2X11 IO-Hub,
662 a.k.a. "ConneXt". The chip is used in place of the standard
663 PC chipset, so all "standard" peripherals are missing. If this
664 option is selected the kernel will still be able to boot on
665 standard PC machines.
668 tristate "Eurobraille/Iris poweroff module"
671 The Iris machines from EuroBraille do not have APM or ACPI support
672 to shut themselves down properly. A special I/O sequence is
673 needed to do so, which is what this module does at
676 This is only for Iris machines from EuroBraille.
680 config SCHED_OMIT_FRAME_POINTER
682 prompt "Single-depth WCHAN output"
685 Calculate simpler /proc/<PID>/wchan values. If this option
686 is disabled then wchan values will recurse back to the
687 caller function. This provides more accurate wchan values,
688 at the expense of slightly more scheduling overhead.
690 If in doubt, say "Y".
692 menuconfig HYPERVISOR_GUEST
693 bool "Linux guest support"
695 Say Y here to enable options for running Linux under various hyper-
696 visors. This option enables basic hypervisor detection and platform
699 If you say N, all options in this submenu will be skipped and
700 disabled, and Linux guest support won't be built in.
705 bool "Enable paravirtualization code"
707 This changes the kernel so it can modify itself when it is run
708 under a hypervisor, potentially improving performance significantly
709 over full virtualization. However, when run without a hypervisor
710 the kernel is theoretically slower and slightly larger.
712 config PARAVIRT_DEBUG
713 bool "paravirt-ops debugging"
714 depends on PARAVIRT && DEBUG_KERNEL
716 Enable to debug paravirt_ops internals. Specifically, BUG if
717 a paravirt_op is missing when it is called.
719 config PARAVIRT_SPINLOCKS
720 bool "Paravirtualization layer for spinlocks"
721 depends on PARAVIRT && SMP
723 Paravirtualized spinlocks allow a pvops backend to replace the
724 spinlock implementation with something virtualization-friendly
725 (for example, block the virtual CPU rather than spinning).
727 It has a minimal impact on native kernels and gives a nice performance
728 benefit on paravirtualized KVM / Xen kernels.
730 If you are unsure how to answer this question, answer Y.
732 config QUEUED_LOCK_STAT
733 bool "Paravirt queued spinlock statistics"
734 depends on PARAVIRT_SPINLOCKS && DEBUG_FS
736 Enable the collection of statistical data on the slowpath
737 behavior of paravirtualized queued spinlocks and report
740 source "arch/x86/xen/Kconfig"
743 bool "KVM Guest support (including kvmclock)"
745 select PARAVIRT_CLOCK
748 This option enables various optimizations for running under the KVM
749 hypervisor. It includes a paravirtualized clock, so that instead
750 of relying on a PIT (or probably other) emulation by the
751 underlying device model, the host provides the guest with
752 timing infrastructure such as time of day, and system time
755 bool "Enable debug information for KVM Guests in debugfs"
756 depends on KVM_GUEST && DEBUG_FS
759 This option enables collection of various statistics for KVM guest.
760 Statistics are displayed in debugfs filesystem. Enabling this option
761 may incur significant overhead.
763 source "arch/x86/lguest/Kconfig"
765 config PARAVIRT_TIME_ACCOUNTING
766 bool "Paravirtual steal time accounting"
770 Select this option to enable fine granularity task steal time
771 accounting. Time spent executing other tasks in parallel with
772 the current vCPU is discounted from the vCPU power. To account for
773 that, there can be a small performance impact.
775 If in doubt, say N here.
777 config PARAVIRT_CLOCK
780 endif #HYPERVISOR_GUEST
785 source "arch/x86/Kconfig.cpu"
789 prompt "HPET Timer Support" if X86_32
791 Use the IA-PC HPET (High Precision Event Timer) to manage
792 time in preference to the PIT and RTC, if a HPET is
794 HPET is the next generation timer replacing legacy 8254s.
795 The HPET provides a stable time base on SMP
796 systems, unlike the TSC, but it is more expensive to access,
797 as it is off-chip. The interface used is documented
798 in the HPET spec, revision 1.
800 You can safely choose Y here. However, HPET will only be
801 activated if the platform and the BIOS support this feature.
802 Otherwise the 8254 will be used for timing services.
804 Choose N to continue using the legacy 8254 timer.
806 config HPET_EMULATE_RTC
808 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
811 def_bool y if X86_INTEL_MID
812 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
814 depends on X86_INTEL_MID && SFI
816 APB timer is the replacement for 8254, HPET on X86 MID platforms.
817 The APBT provides a stable time base on SMP
818 systems, unlike the TSC, but it is more expensive to access,
819 as it is off-chip. APB timers are always running regardless of CPU
820 C states, they are used as per CPU clockevent device when possible.
822 # Mark as expert because too many people got it wrong.
823 # The code disables itself when not needed.
826 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
827 bool "Enable DMI scanning" if EXPERT
829 Enabled scanning of DMI to identify machine quirks. Say Y
830 here unless you have verified that your setup is not
831 affected by entries in the DMI blacklist. Required by PNP
835 bool "Old AMD GART IOMMU support"
837 depends on X86_64 && PCI && AMD_NB
839 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
840 GART based hardware IOMMUs.
842 The GART supports full DMA access for devices with 32-bit access
843 limitations, on systems with more than 3 GB. This is usually needed
844 for USB, sound, many IDE/SATA chipsets and some other devices.
846 Newer systems typically have a modern AMD IOMMU, supported via
847 the CONFIG_AMD_IOMMU=y config option.
849 In normal configurations this driver is only active when needed:
850 there's more than 3 GB of memory and the system contains a
851 32-bit limited device.
856 bool "IBM Calgary IOMMU support"
858 depends on X86_64 && PCI
860 Support for hardware IOMMUs in IBM's xSeries x366 and x460
861 systems. Needed to run systems with more than 3GB of memory
862 properly with 32-bit PCI devices that do not support DAC
863 (Double Address Cycle). Calgary also supports bus level
864 isolation, where all DMAs pass through the IOMMU. This
865 prevents them from going anywhere except their intended
866 destination. This catches hard-to-find kernel bugs and
867 mis-behaving drivers and devices that do not use the DMA-API
868 properly to set up their DMA buffers. The IOMMU can be
869 turned off at boot time with the iommu=off parameter.
870 Normally the kernel will make the right choice by itself.
873 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
875 prompt "Should Calgary be enabled by default?"
876 depends on CALGARY_IOMMU
878 Should Calgary be enabled by default? if you choose 'y', Calgary
879 will be used (if it exists). If you choose 'n', Calgary will not be
880 used even if it exists. If you choose 'n' and would like to use
881 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
884 # need this always selected by IOMMU for the VIA workaround
888 Support for software bounce buffers used on x86-64 systems
889 which don't have a hardware IOMMU. Using this PCI devices
890 which can only access 32-bits of memory can be used on systems
891 with more than 3 GB of memory.
896 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
899 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
900 depends on X86_64 && SMP && DEBUG_KERNEL
901 select CPUMASK_OFFSTACK
903 Enable maximum number of CPUS and NUMA Nodes for this architecture.
907 int "Maximum number of CPUs" if SMP && !MAXSMP
908 range 2 8 if SMP && X86_32 && !X86_BIGSMP
909 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
910 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
912 default "8192" if MAXSMP
913 default "32" if SMP && X86_BIGSMP
914 default "8" if SMP && X86_32
917 This allows you to specify the maximum number of CPUs which this
918 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
919 supported value is 8192, otherwise the maximum value is 512. The
920 minimum value which makes sense is 2.
922 This is purely to save memory - each supported CPU adds
923 approximately eight kilobytes to the kernel image.
926 bool "SMT (Hyperthreading) scheduler support"
929 SMT scheduler support improves the CPU scheduler's decision making
930 when dealing with Intel Pentium 4 chips with HyperThreading at a
931 cost of slightly increased overhead in some places. If unsure say
936 prompt "Multi-core scheduler support"
939 Multi-core scheduler support improves the CPU scheduler's decision
940 making when dealing with multi-core CPU chips at a cost of slightly
941 increased overhead in some places. If unsure say N here.
943 source "kernel/Kconfig.preempt"
947 depends on !SMP && X86_LOCAL_APIC
950 bool "Local APIC support on uniprocessors" if !PCI_MSI
952 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
954 A local APIC (Advanced Programmable Interrupt Controller) is an
955 integrated interrupt controller in the CPU. If you have a single-CPU
956 system which has a processor with a local APIC, you can say Y here to
957 enable and use it. If you say Y here even though your machine doesn't
958 have a local APIC, then the kernel will still run with no slowdown at
959 all. The local APIC supports CPU-generated self-interrupts (timer,
960 performance counters), and the NMI watchdog which detects hard
964 bool "IO-APIC support on uniprocessors"
965 depends on X86_UP_APIC
967 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
968 SMP-capable replacement for PC-style interrupt controllers. Most
969 SMP systems and many recent uniprocessor systems have one.
971 If you have a single-CPU system with an IO-APIC, you can say Y here
972 to use it. If you say Y here even though your machine doesn't have
973 an IO-APIC, then the kernel will still run with no slowdown at all.
975 config X86_LOCAL_APIC
977 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
978 select IRQ_DOMAIN_HIERARCHY
979 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
983 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
985 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
986 bool "Reroute for broken boot IRQs"
987 depends on X86_IO_APIC
989 This option enables a workaround that fixes a source of
990 spurious interrupts. This is recommended when threaded
991 interrupt handling is used on systems where the generation of
992 superfluous "boot interrupts" cannot be disabled.
994 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
995 entry in the chipset's IO-APIC is masked (as, e.g. the RT
996 kernel does during interrupt handling). On chipsets where this
997 boot IRQ generation cannot be disabled, this workaround keeps
998 the original IRQ line masked so that only the equivalent "boot
999 IRQ" is delivered to the CPUs. The workaround also tells the
1000 kernel to set up the IRQ handler on the boot IRQ line. In this
1001 way only one interrupt is delivered to the kernel. Otherwise
1002 the spurious second interrupt may cause the kernel to bring
1003 down (vital) interrupt lines.
1005 Only affects "broken" chipsets. Interrupt sharing may be
1006 increased on these systems.
1009 bool "Machine Check / overheating reporting"
1010 select GENERIC_ALLOCATOR
1013 Machine Check support allows the processor to notify the
1014 kernel if it detects a problem (e.g. overheating, data corruption).
1015 The action the kernel takes depends on the severity of the problem,
1016 ranging from warning messages to halting the machine.
1018 config X86_MCE_INTEL
1020 prompt "Intel MCE features"
1021 depends on X86_MCE && X86_LOCAL_APIC
1023 Additional support for intel specific MCE features such as
1024 the thermal monitor.
1028 prompt "AMD MCE features"
1029 depends on X86_MCE && X86_LOCAL_APIC
1031 Additional support for AMD specific MCE features such as
1032 the DRAM Error Threshold.
1034 config X86_ANCIENT_MCE
1035 bool "Support for old Pentium 5 / WinChip machine checks"
1036 depends on X86_32 && X86_MCE
1038 Include support for machine check handling on old Pentium 5 or WinChip
1039 systems. These typically need to be enabled explicitly on the command
1042 config X86_MCE_THRESHOLD
1043 depends on X86_MCE_AMD || X86_MCE_INTEL
1046 config X86_MCE_INJECT
1048 tristate "Machine check injector support"
1050 Provide support for injecting machine checks for testing purposes.
1051 If you don't know what a machine check is and you don't do kernel
1052 QA it is safe to say n.
1054 config X86_THERMAL_VECTOR
1056 depends on X86_MCE_INTEL
1058 source "arch/x86/events/Kconfig"
1060 config X86_LEGACY_VM86
1061 bool "Legacy VM86 support"
1065 This option allows user programs to put the CPU into V8086
1066 mode, which is an 80286-era approximation of 16-bit real mode.
1068 Some very old versions of X and/or vbetool require this option
1069 for user mode setting. Similarly, DOSEMU will use it if
1070 available to accelerate real mode DOS programs. However, any
1071 recent version of DOSEMU, X, or vbetool should be fully
1072 functional even without kernel VM86 support, as they will all
1073 fall back to software emulation. Nevertheless, if you are using
1074 a 16-bit DOS program where 16-bit performance matters, vm86
1075 mode might be faster than emulation and you might want to
1078 Note that any app that works on a 64-bit kernel is unlikely to
1079 need this option, as 64-bit kernels don't, and can't, support
1080 V8086 mode. This option is also unrelated to 16-bit protected
1081 mode and is not needed to run most 16-bit programs under Wine.
1083 Enabling this option increases the complexity of the kernel
1084 and slows down exception handling a tiny bit.
1086 If unsure, say N here.
1090 default X86_LEGACY_VM86
1093 bool "Enable support for 16-bit segments" if EXPERT
1095 depends on MODIFY_LDT_SYSCALL
1097 This option is required by programs like Wine to run 16-bit
1098 protected mode legacy code on x86 processors. Disabling
1099 this option saves about 300 bytes on i386, or around 6K text
1100 plus 16K runtime memory on x86-64,
1104 depends on X86_16BIT && X86_32
1108 depends on X86_16BIT && X86_64
1110 config X86_VSYSCALL_EMULATION
1111 bool "Enable vsyscall emulation" if EXPERT
1115 This enables emulation of the legacy vsyscall page. Disabling
1116 it is roughly equivalent to booting with vsyscall=none, except
1117 that it will also disable the helpful warning if a program
1118 tries to use a vsyscall. With this option set to N, offending
1119 programs will just segfault, citing addresses of the form
1122 This option is required by many programs built before 2013, and
1123 care should be used even with newer programs if set to N.
1125 Disabling this option saves about 7K of kernel size and
1126 possibly 4K of additional runtime pagetable memory.
1129 tristate "Toshiba Laptop support"
1132 This adds a driver to safely access the System Management Mode of
1133 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1134 not work on models with a Phoenix BIOS. The System Management Mode
1135 is used to set the BIOS and power saving options on Toshiba portables.
1137 For information on utilities to make use of this driver see the
1138 Toshiba Linux utilities web site at:
1139 <http://www.buzzard.org.uk/toshiba/>.
1141 Say Y if you intend to run this kernel on a Toshiba portable.
1145 tristate "Dell i8k legacy laptop support"
1147 select SENSORS_DELL_SMM
1149 This option enables legacy /proc/i8k userspace interface in hwmon
1150 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1151 temperature and allows controlling fan speeds of Dell laptops via
1152 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1153 it reports also power and hotkey status. For fan speed control is
1154 needed userspace package i8kutils.
1156 Say Y if you intend to run this kernel on old Dell laptops or want to
1157 use userspace package i8kutils.
1160 config X86_REBOOTFIXUPS
1161 bool "Enable X86 board specific fixups for reboot"
1164 This enables chipset and/or board specific fixups to be done
1165 in order to get reboot to work correctly. This is only needed on
1166 some combinations of hardware and BIOS. The symptom, for which
1167 this config is intended, is when reboot ends with a stalled/hung
1170 Currently, the only fixup is for the Geode machines using
1171 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1173 Say Y if you want to enable the fixup. Currently, it's safe to
1174 enable this option even if you don't need it.
1178 bool "CPU microcode loading support"
1180 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1183 If you say Y here, you will be able to update the microcode on
1184 Intel and AMD processors. The Intel support is for the IA32 family,
1185 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1186 AMD support is for families 0x10 and later. You will obviously need
1187 the actual microcode binary data itself which is not shipped with
1190 The preferred method to load microcode from a detached initrd is described
1191 in Documentation/x86/early-microcode.txt. For that you need to enable
1192 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1193 initrd for microcode blobs.
1195 In addition, you can build-in the microcode into the kernel. For that you
1196 need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
1197 to the CONFIG_EXTRA_FIRMWARE config option.
1199 config MICROCODE_INTEL
1200 bool "Intel microcode loading support"
1201 depends on MICROCODE
1205 This options enables microcode patch loading support for Intel
1208 For the current Intel microcode data package go to
1209 <https://downloadcenter.intel.com> and search for
1210 'Linux Processor Microcode Data File'.
1212 config MICROCODE_AMD
1213 bool "AMD microcode loading support"
1214 depends on MICROCODE
1217 If you select this option, microcode patch loading support for AMD
1218 processors will be enabled.
1220 config MICROCODE_OLD_INTERFACE
1222 depends on MICROCODE
1225 tristate "/dev/cpu/*/msr - Model-specific register support"
1227 This device gives privileged processes access to the x86
1228 Model-Specific Registers (MSRs). It is a character device with
1229 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1230 MSR accesses are directed to a specific CPU on multi-processor
1234 tristate "/dev/cpu/*/cpuid - CPU information support"
1236 This device gives processes access to the x86 CPUID instruction to
1237 be executed on a specific processor. It is a character device
1238 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1242 prompt "High Memory Support"
1249 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1250 However, the address space of 32-bit x86 processors is only 4
1251 Gigabytes large. That means that, if you have a large amount of
1252 physical memory, not all of it can be "permanently mapped" by the
1253 kernel. The physical memory that's not permanently mapped is called
1256 If you are compiling a kernel which will never run on a machine with
1257 more than 1 Gigabyte total physical RAM, answer "off" here (default
1258 choice and suitable for most users). This will result in a "3GB/1GB"
1259 split: 3GB are mapped so that each process sees a 3GB virtual memory
1260 space and the remaining part of the 4GB virtual memory space is used
1261 by the kernel to permanently map as much physical memory as
1264 If the machine has between 1 and 4 Gigabytes physical RAM, then
1267 If more than 4 Gigabytes is used then answer "64GB" here. This
1268 selection turns Intel PAE (Physical Address Extension) mode on.
1269 PAE implements 3-level paging on IA32 processors. PAE is fully
1270 supported by Linux, PAE mode is implemented on all recent Intel
1271 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1272 then the kernel will not boot on CPUs that don't support PAE!
1274 The actual amount of total physical memory will either be
1275 auto detected or can be forced by using a kernel command line option
1276 such as "mem=256M". (Try "man bootparam" or see the documentation of
1277 your boot loader (lilo or loadlin) about how to pass options to the
1278 kernel at boot time.)
1280 If unsure, say "off".
1285 Select this if you have a 32-bit processor and between 1 and 4
1286 gigabytes of physical RAM.
1293 Select this if you have a 32-bit processor and more than 4
1294 gigabytes of physical RAM.
1299 prompt "Memory split" if EXPERT
1303 Select the desired split between kernel and user memory.
1305 If the address range available to the kernel is less than the
1306 physical memory installed, the remaining memory will be available
1307 as "high memory". Accessing high memory is a little more costly
1308 than low memory, as it needs to be mapped into the kernel first.
1309 Note that increasing the kernel address space limits the range
1310 available to user programs, making the address space there
1311 tighter. Selecting anything other than the default 3G/1G split
1312 will also likely make your kernel incompatible with binary-only
1315 If you are not absolutely sure what you are doing, leave this
1319 bool "3G/1G user/kernel split"
1320 config VMSPLIT_3G_OPT
1322 bool "3G/1G user/kernel split (for full 1G low memory)"
1324 bool "2G/2G user/kernel split"
1325 config VMSPLIT_2G_OPT
1327 bool "2G/2G user/kernel split (for full 2G low memory)"
1329 bool "1G/3G user/kernel split"
1334 default 0xB0000000 if VMSPLIT_3G_OPT
1335 default 0x80000000 if VMSPLIT_2G
1336 default 0x78000000 if VMSPLIT_2G_OPT
1337 default 0x40000000 if VMSPLIT_1G
1343 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1346 bool "PAE (Physical Address Extension) Support"
1347 depends on X86_32 && !HIGHMEM4G
1350 PAE is required for NX support, and furthermore enables
1351 larger swapspace support for non-overcommit purposes. It
1352 has the cost of more pagetable lookup overhead, and also
1353 consumes more pagetable space per process.
1355 config ARCH_PHYS_ADDR_T_64BIT
1357 depends on X86_64 || X86_PAE
1359 config ARCH_DMA_ADDR_T_64BIT
1361 depends on X86_64 || HIGHMEM64G
1363 config X86_DIRECT_GBPAGES
1365 depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1367 Certain kernel features effectively disable kernel
1368 linear 1 GB mappings (even if the CPU otherwise
1369 supports them), so don't confuse the user by printing
1370 that we have them enabled.
1372 # Common NUMA Features
1374 bool "Numa Memory Allocation and Scheduler Support"
1376 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1377 default y if X86_BIGSMP
1379 Enable NUMA (Non Uniform Memory Access) support.
1381 The kernel will try to allocate memory used by a CPU on the
1382 local memory controller of the CPU and add some more
1383 NUMA awareness to the kernel.
1385 For 64-bit this is recommended if the system is Intel Core i7
1386 (or later), AMD Opteron, or EM64T NUMA.
1388 For 32-bit this is only needed if you boot a 32-bit
1389 kernel on a 64-bit NUMA platform.
1391 Otherwise, you should say N.
1395 prompt "Old style AMD Opteron NUMA detection"
1396 depends on X86_64 && NUMA && PCI
1398 Enable AMD NUMA node topology detection. You should say Y here if
1399 you have a multi processor AMD system. This uses an old method to
1400 read the NUMA configuration directly from the builtin Northbridge
1401 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1402 which also takes priority if both are compiled in.
1404 config X86_64_ACPI_NUMA
1406 prompt "ACPI NUMA detection"
1407 depends on X86_64 && NUMA && ACPI && PCI
1410 Enable ACPI SRAT based node topology detection.
1412 # Some NUMA nodes have memory ranges that span
1413 # other nodes. Even though a pfn is valid and
1414 # between a node's start and end pfns, it may not
1415 # reside on that node. See memmap_init_zone()
1417 config NODES_SPAN_OTHER_NODES
1419 depends on X86_64_ACPI_NUMA
1422 bool "NUMA emulation"
1425 Enable NUMA emulation. A flat machine will be split
1426 into virtual nodes when booted with "numa=fake=N", where N is the
1427 number of nodes. This is only useful for debugging.
1430 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1432 default "10" if MAXSMP
1433 default "6" if X86_64
1435 depends on NEED_MULTIPLE_NODES
1437 Specify the maximum number of NUMA Nodes available on the target
1438 system. Increases memory reserved to accommodate various tables.
1440 config ARCH_HAVE_MEMORY_PRESENT
1442 depends on X86_32 && DISCONTIGMEM
1444 config NEED_NODE_MEMMAP_SIZE
1446 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1448 config ARCH_FLATMEM_ENABLE
1450 depends on X86_32 && !NUMA
1452 config ARCH_DISCONTIGMEM_ENABLE
1454 depends on NUMA && X86_32
1456 config ARCH_DISCONTIGMEM_DEFAULT
1458 depends on NUMA && X86_32
1460 config ARCH_SPARSEMEM_ENABLE
1462 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1463 select SPARSEMEM_STATIC if X86_32
1464 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1466 config ARCH_SPARSEMEM_DEFAULT
1470 config ARCH_SELECT_MEMORY_MODEL
1472 depends on ARCH_SPARSEMEM_ENABLE
1474 config ARCH_MEMORY_PROBE
1475 bool "Enable sysfs memory/probe interface"
1476 depends on X86_64 && MEMORY_HOTPLUG
1478 This option enables a sysfs memory/probe interface for testing.
1479 See Documentation/memory-hotplug.txt for more information.
1480 If you are unsure how to answer this question, answer N.
1482 config ARCH_PROC_KCORE_TEXT
1484 depends on X86_64 && PROC_KCORE
1486 config ILLEGAL_POINTER_VALUE
1489 default 0xdead000000000000 if X86_64
1493 config X86_PMEM_LEGACY_DEVICE
1496 config X86_PMEM_LEGACY
1497 tristate "Support non-standard NVDIMMs and ADR protected memory"
1498 depends on PHYS_ADDR_T_64BIT
1500 select X86_PMEM_LEGACY_DEVICE
1503 Treat memory marked using the non-standard e820 type of 12 as used
1504 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1505 The kernel will offer these regions to the 'pmem' driver so
1506 they can be used for persistent storage.
1511 bool "Allocate 3rd-level pagetables from highmem"
1514 The VM uses one page table entry for each page of physical memory.
1515 For systems with a lot of RAM, this can be wasteful of precious
1516 low memory. Setting this option will put user-space page table
1517 entries in high memory.
1519 config X86_CHECK_BIOS_CORRUPTION
1520 bool "Check for low memory corruption"
1522 Periodically check for memory corruption in low memory, which
1523 is suspected to be caused by BIOS. Even when enabled in the
1524 configuration, it is disabled at runtime. Enable it by
1525 setting "memory_corruption_check=1" on the kernel command
1526 line. By default it scans the low 64k of memory every 60
1527 seconds; see the memory_corruption_check_size and
1528 memory_corruption_check_period parameters in
1529 Documentation/kernel-parameters.txt to adjust this.
1531 When enabled with the default parameters, this option has
1532 almost no overhead, as it reserves a relatively small amount
1533 of memory and scans it infrequently. It both detects corruption
1534 and prevents it from affecting the running system.
1536 It is, however, intended as a diagnostic tool; if repeatable
1537 BIOS-originated corruption always affects the same memory,
1538 you can use memmap= to prevent the kernel from using that
1541 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1542 bool "Set the default setting of memory_corruption_check"
1543 depends on X86_CHECK_BIOS_CORRUPTION
1546 Set whether the default state of memory_corruption_check is
1549 config X86_RESERVE_LOW
1550 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1554 Specify the amount of low memory to reserve for the BIOS.
1556 The first page contains BIOS data structures that the kernel
1557 must not use, so that page must always be reserved.
1559 By default we reserve the first 64K of physical RAM, as a
1560 number of BIOSes are known to corrupt that memory range
1561 during events such as suspend/resume or monitor cable
1562 insertion, so it must not be used by the kernel.
1564 You can set this to 4 if you are absolutely sure that you
1565 trust the BIOS to get all its memory reservations and usages
1566 right. If you know your BIOS have problems beyond the
1567 default 64K area, you can set this to 640 to avoid using the
1568 entire low memory range.
1570 If you have doubts about the BIOS (e.g. suspend/resume does
1571 not work or there's kernel crashes after certain hardware
1572 hotplug events) then you might want to enable
1573 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1574 typical corruption patterns.
1576 Leave this to the default value of 64 if you are unsure.
1578 config MATH_EMULATION
1580 depends on MODIFY_LDT_SYSCALL
1581 prompt "Math emulation" if X86_32
1583 Linux can emulate a math coprocessor (used for floating point
1584 operations) if you don't have one. 486DX and Pentium processors have
1585 a math coprocessor built in, 486SX and 386 do not, unless you added
1586 a 487DX or 387, respectively. (The messages during boot time can
1587 give you some hints here ["man dmesg"].) Everyone needs either a
1588 coprocessor or this emulation.
1590 If you don't have a math coprocessor, you need to say Y here; if you
1591 say Y here even though you have a coprocessor, the coprocessor will
1592 be used nevertheless. (This behavior can be changed with the kernel
1593 command line option "no387", which comes handy if your coprocessor
1594 is broken. Try "man bootparam" or see the documentation of your boot
1595 loader (lilo or loadlin) about how to pass options to the kernel at
1596 boot time.) This means that it is a good idea to say Y here if you
1597 intend to use this kernel on different machines.
1599 More information about the internals of the Linux math coprocessor
1600 emulation can be found in <file:arch/x86/math-emu/README>.
1602 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1603 kernel, it won't hurt.
1607 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1609 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1610 the Memory Type Range Registers (MTRRs) may be used to control
1611 processor access to memory ranges. This is most useful if you have
1612 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1613 allows bus write transfers to be combined into a larger transfer
1614 before bursting over the PCI/AGP bus. This can increase performance
1615 of image write operations 2.5 times or more. Saying Y here creates a
1616 /proc/mtrr file which may be used to manipulate your processor's
1617 MTRRs. Typically the X server should use this.
1619 This code has a reasonably generic interface so that similar
1620 control registers on other processors can be easily supported
1623 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1624 Registers (ARRs) which provide a similar functionality to MTRRs. For
1625 these, the ARRs are used to emulate the MTRRs.
1626 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1627 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1628 write-combining. All of these processors are supported by this code
1629 and it makes sense to say Y here if you have one of them.
1631 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1632 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1633 can lead to all sorts of problems, so it's good to say Y here.
1635 You can safely say Y even if your machine doesn't have MTRRs, you'll
1636 just add about 9 KB to your kernel.
1638 See <file:Documentation/x86/mtrr.txt> for more information.
1640 config MTRR_SANITIZER
1642 prompt "MTRR cleanup support"
1645 Convert MTRR layout from continuous to discrete, so X drivers can
1646 add writeback entries.
1648 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1649 The largest mtrr entry size for a continuous block can be set with
1654 config MTRR_SANITIZER_ENABLE_DEFAULT
1655 int "MTRR cleanup enable value (0-1)"
1658 depends on MTRR_SANITIZER
1660 Enable mtrr cleanup default value
1662 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1663 int "MTRR cleanup spare reg num (0-7)"
1666 depends on MTRR_SANITIZER
1668 mtrr cleanup spare entries default, it can be changed via
1669 mtrr_spare_reg_nr=N on the kernel command line.
1673 prompt "x86 PAT support" if EXPERT
1676 Use PAT attributes to setup page level cache control.
1678 PATs are the modern equivalents of MTRRs and are much more
1679 flexible than MTRRs.
1681 Say N here if you see bootup problems (boot crash, boot hang,
1682 spontaneous reboots) or a non-working video driver.
1686 config ARCH_USES_PG_UNCACHED
1692 prompt "x86 architectural random number generator" if EXPERT
1694 Enable the x86 architectural RDRAND instruction
1695 (Intel Bull Mountain technology) to generate random numbers.
1696 If supported, this is a high bandwidth, cryptographically
1697 secure hardware random number generator.
1701 prompt "Supervisor Mode Access Prevention" if EXPERT
1703 Supervisor Mode Access Prevention (SMAP) is a security
1704 feature in newer Intel processors. There is a small
1705 performance cost if this enabled and turned on; there is
1706 also a small increase in the kernel size if this is enabled.
1710 config X86_INTEL_MPX
1711 prompt "Intel MPX (Memory Protection Extensions)"
1713 depends on CPU_SUP_INTEL
1715 MPX provides hardware features that can be used in
1716 conjunction with compiler-instrumented code to check
1717 memory references. It is designed to detect buffer
1718 overflow or underflow bugs.
1720 This option enables running applications which are
1721 instrumented or otherwise use MPX. It does not use MPX
1722 itself inside the kernel or to protect the kernel
1723 against bad memory references.
1725 Enabling this option will make the kernel larger:
1726 ~8k of kernel text and 36 bytes of data on a 64-bit
1727 defconfig. It adds a long to the 'mm_struct' which
1728 will increase the kernel memory overhead of each
1729 process and adds some branches to paths used during
1730 exec() and munmap().
1732 For details, see Documentation/x86/intel_mpx.txt
1736 config X86_INTEL_MEMORY_PROTECTION_KEYS
1737 prompt "Intel Memory Protection Keys"
1739 # Note: only available in 64-bit mode
1740 depends on CPU_SUP_INTEL && X86_64
1742 Memory Protection Keys provides a mechanism for enforcing
1743 page-based protections, but without requiring modification of the
1744 page tables when an application changes protection domains.
1746 For details, see Documentation/x86/protection-keys.txt
1751 bool "EFI runtime service support"
1754 select EFI_RUNTIME_WRAPPERS
1756 This enables the kernel to use EFI runtime services that are
1757 available (such as the EFI variable services).
1759 This option is only useful on systems that have EFI firmware.
1760 In addition, you should use the latest ELILO loader available
1761 at <http://elilo.sourceforge.net> in order to take advantage
1762 of EFI runtime services. However, even with this option, the
1763 resultant kernel should continue to boot on existing non-EFI
1767 bool "EFI stub support"
1768 depends on EFI && !X86_USE_3DNOW
1771 This kernel feature allows a bzImage to be loaded directly
1772 by EFI firmware without the use of a bootloader.
1774 See Documentation/efi-stub.txt for more information.
1777 bool "EFI mixed-mode support"
1778 depends on EFI_STUB && X86_64
1780 Enabling this feature allows a 64-bit kernel to be booted
1781 on a 32-bit firmware, provided that your CPU supports 64-bit
1784 Note that it is not possible to boot a mixed-mode enabled
1785 kernel via the EFI boot stub - a bootloader that supports
1786 the EFI handover protocol must be used.
1792 prompt "Enable seccomp to safely compute untrusted bytecode"
1794 This kernel feature is useful for number crunching applications
1795 that may need to compute untrusted bytecode during their
1796 execution. By using pipes or other transports made available to
1797 the process as file descriptors supporting the read/write
1798 syscalls, it's possible to isolate those applications in
1799 their own address space using seccomp. Once seccomp is
1800 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1801 and the task is only allowed to execute a few safe syscalls
1802 defined by each seccomp mode.
1804 If unsure, say Y. Only embedded should say N here.
1806 source kernel/Kconfig.hz
1809 bool "kexec system call"
1812 kexec is a system call that implements the ability to shutdown your
1813 current kernel, and to start another kernel. It is like a reboot
1814 but it is independent of the system firmware. And like a reboot
1815 you can start any kernel with it, not just Linux.
1817 The name comes from the similarity to the exec system call.
1819 It is an ongoing process to be certain the hardware in a machine
1820 is properly shutdown, so do not be surprised if this code does not
1821 initially work for you. As of this writing the exact hardware
1822 interface is strongly in flux, so no good recommendation can be
1826 bool "kexec file based system call"
1831 depends on CRYPTO_SHA256=y
1833 This is new version of kexec system call. This system call is
1834 file based and takes file descriptors as system call argument
1835 for kernel and initramfs as opposed to list of segments as
1836 accepted by previous system call.
1838 config KEXEC_VERIFY_SIG
1839 bool "Verify kernel signature during kexec_file_load() syscall"
1840 depends on KEXEC_FILE
1842 This option makes kernel signature verification mandatory for
1843 the kexec_file_load() syscall.
1845 In addition to that option, you need to enable signature
1846 verification for the corresponding kernel image type being
1847 loaded in order for this to work.
1849 config KEXEC_BZIMAGE_VERIFY_SIG
1850 bool "Enable bzImage signature verification support"
1851 depends on KEXEC_VERIFY_SIG
1852 depends on SIGNED_PE_FILE_VERIFICATION
1853 select SYSTEM_TRUSTED_KEYRING
1855 Enable bzImage signature verification support.
1858 bool "kernel crash dumps"
1859 depends on X86_64 || (X86_32 && HIGHMEM)
1861 Generate crash dump after being started by kexec.
1862 This should be normally only set in special crash dump kernels
1863 which are loaded in the main kernel with kexec-tools into
1864 a specially reserved region and then later executed after
1865 a crash by kdump/kexec. The crash dump kernel must be compiled
1866 to a memory address not used by the main kernel or BIOS using
1867 PHYSICAL_START, or it must be built as a relocatable image
1868 (CONFIG_RELOCATABLE=y).
1869 For more details see Documentation/kdump/kdump.txt
1873 depends on KEXEC && HIBERNATION
1875 Jump between original kernel and kexeced kernel and invoke
1876 code in physical address mode via KEXEC
1878 config PHYSICAL_START
1879 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1882 This gives the physical address where the kernel is loaded.
1884 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1885 bzImage will decompress itself to above physical address and
1886 run from there. Otherwise, bzImage will run from the address where
1887 it has been loaded by the boot loader and will ignore above physical
1890 In normal kdump cases one does not have to set/change this option
1891 as now bzImage can be compiled as a completely relocatable image
1892 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1893 address. This option is mainly useful for the folks who don't want
1894 to use a bzImage for capturing the crash dump and want to use a
1895 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1896 to be specifically compiled to run from a specific memory area
1897 (normally a reserved region) and this option comes handy.
1899 So if you are using bzImage for capturing the crash dump,
1900 leave the value here unchanged to 0x1000000 and set
1901 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1902 for capturing the crash dump change this value to start of
1903 the reserved region. In other words, it can be set based on
1904 the "X" value as specified in the "crashkernel=YM@XM"
1905 command line boot parameter passed to the panic-ed
1906 kernel. Please take a look at Documentation/kdump/kdump.txt
1907 for more details about crash dumps.
1909 Usage of bzImage for capturing the crash dump is recommended as
1910 one does not have to build two kernels. Same kernel can be used
1911 as production kernel and capture kernel. Above option should have
1912 gone away after relocatable bzImage support is introduced. But it
1913 is present because there are users out there who continue to use
1914 vmlinux for dump capture. This option should go away down the
1917 Don't change this unless you know what you are doing.
1920 bool "Build a relocatable kernel"
1923 This builds a kernel image that retains relocation information
1924 so it can be loaded someplace besides the default 1MB.
1925 The relocations tend to make the kernel binary about 10% larger,
1926 but are discarded at runtime.
1928 One use is for the kexec on panic case where the recovery kernel
1929 must live at a different physical address than the primary
1932 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1933 it has been loaded at and the compile time physical address
1934 (CONFIG_PHYSICAL_START) is used as the minimum location.
1936 config RANDOMIZE_BASE
1937 bool "Randomize the address of the kernel image (KASLR)"
1938 depends on RELOCATABLE
1941 In support of Kernel Address Space Layout Randomization (KASLR),
1942 this randomizes the physical address at which the kernel image
1943 is decompressed and the virtual address where the kernel
1944 image is mapped, as a security feature that deters exploit
1945 attempts relying on knowledge of the location of kernel
1948 On 64-bit, the kernel physical and virtual addresses are
1949 randomized separately. The physical address will be anywhere
1950 between 16MB and the top of physical memory (up to 64TB). The
1951 virtual address will be randomized from 16MB up to 1GB (9 bits
1952 of entropy). Note that this also reduces the memory space
1953 available to kernel modules from 1.5GB to 1GB.
1955 On 32-bit, the kernel physical and virtual addresses are
1956 randomized together. They will be randomized from 16MB up to
1957 512MB (8 bits of entropy).
1959 Entropy is generated using the RDRAND instruction if it is
1960 supported. If RDTSC is supported, its value is mixed into
1961 the entropy pool as well. If neither RDRAND nor RDTSC are
1962 supported, then entropy is read from the i8254 timer. The
1963 usable entropy is limited by the kernel being built using
1964 2GB addressing, and that PHYSICAL_ALIGN must be at a
1965 minimum of 2MB. As a result, only 10 bits of entropy are
1966 theoretically possible, but the implementations are further
1967 limited due to memory layouts.
1969 If CONFIG_HIBERNATE is also enabled, KASLR is disabled at boot
1970 time. To enable it, boot with "kaslr" on the kernel command
1971 line (which will also disable hibernation).
1975 # Relocation on x86 needs some additional build support
1976 config X86_NEED_RELOCS
1978 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1980 config PHYSICAL_ALIGN
1981 hex "Alignment value to which kernel should be aligned"
1983 range 0x2000 0x1000000 if X86_32
1984 range 0x200000 0x1000000 if X86_64
1986 This value puts the alignment restrictions on physical address
1987 where kernel is loaded and run from. Kernel is compiled for an
1988 address which meets above alignment restriction.
1990 If bootloader loads the kernel at a non-aligned address and
1991 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1992 address aligned to above value and run from there.
1994 If bootloader loads the kernel at a non-aligned address and
1995 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1996 load address and decompress itself to the address it has been
1997 compiled for and run from there. The address for which kernel is
1998 compiled already meets above alignment restrictions. Hence the
1999 end result is that kernel runs from a physical address meeting
2000 above alignment restrictions.
2002 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2003 this value must be a multiple of 0x200000.
2005 Don't change this unless you know what you are doing.
2007 config RANDOMIZE_MEMORY
2008 bool "Randomize the kernel memory sections"
2010 depends on RANDOMIZE_BASE
2011 default RANDOMIZE_BASE
2013 Randomizes the base virtual address of kernel memory sections
2014 (physical memory mapping, vmalloc & vmemmap). This security feature
2015 makes exploits relying on predictable memory locations less reliable.
2017 The order of allocations remains unchanged. Entropy is generated in
2018 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2019 configuration have in average 30,000 different possible virtual
2020 addresses for each memory section.
2024 config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2025 hex "Physical memory mapping padding" if EXPERT
2026 depends on RANDOMIZE_MEMORY
2027 default "0xa" if MEMORY_HOTPLUG
2029 range 0x1 0x40 if MEMORY_HOTPLUG
2032 Define the padding in terabytes added to the existing physical
2033 memory size during kernel memory randomization. It is useful
2034 for memory hotplug support but reduces the entropy available for
2035 address randomization.
2037 If unsure, leave at the default value.
2040 bool "Support for hot-pluggable CPUs"
2043 Say Y here to allow turning CPUs off and on. CPUs can be
2044 controlled through /sys/devices/system/cpu.
2045 ( Note: power management support will enable this option
2046 automatically on SMP systems. )
2047 Say N if you want to disable CPU hotplug.
2049 config BOOTPARAM_HOTPLUG_CPU0
2050 bool "Set default setting of cpu0_hotpluggable"
2052 depends on HOTPLUG_CPU
2054 Set whether default state of cpu0_hotpluggable is on or off.
2056 Say Y here to enable CPU0 hotplug by default. If this switch
2057 is turned on, there is no need to give cpu0_hotplug kernel
2058 parameter and the CPU0 hotplug feature is enabled by default.
2060 Please note: there are two known CPU0 dependencies if you want
2061 to enable the CPU0 hotplug feature either by this switch or by
2062 cpu0_hotplug kernel parameter.
2064 First, resume from hibernate or suspend always starts from CPU0.
2065 So hibernate and suspend are prevented if CPU0 is offline.
2067 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2068 offline if any interrupt can not migrate out of CPU0. There may
2069 be other CPU0 dependencies.
2071 Please make sure the dependencies are under your control before
2072 you enable this feature.
2074 Say N if you don't want to enable CPU0 hotplug feature by default.
2075 You still can enable the CPU0 hotplug feature at boot by kernel
2076 parameter cpu0_hotplug.
2078 config DEBUG_HOTPLUG_CPU0
2080 prompt "Debug CPU0 hotplug"
2081 depends on HOTPLUG_CPU
2083 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2084 soon as possible and boots up userspace with CPU0 offlined. User
2085 can online CPU0 back after boot time.
2087 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2088 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2089 compilation or giving cpu0_hotplug kernel parameter at boot.
2095 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2096 depends on X86_32 || IA32_EMULATION
2098 Certain buggy versions of glibc will crash if they are
2099 presented with a 32-bit vDSO that is not mapped at the address
2100 indicated in its segment table.
2102 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2103 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2104 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2105 the only released version with the bug, but OpenSUSE 9
2106 contains a buggy "glibc 2.3.2".
2108 The symptom of the bug is that everything crashes on startup, saying:
2109 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2111 Saying Y here changes the default value of the vdso32 boot
2112 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2113 This works around the glibc bug but hurts performance.
2115 If unsure, say N: if you are compiling your own kernel, you
2116 are unlikely to be using a buggy version of glibc.
2119 prompt "vsyscall table for legacy applications"
2121 default LEGACY_VSYSCALL_EMULATE
2123 Legacy user code that does not know how to find the vDSO expects
2124 to be able to issue three syscalls by calling fixed addresses in
2125 kernel space. Since this location is not randomized with ASLR,
2126 it can be used to assist security vulnerability exploitation.
2128 This setting can be changed at boot time via the kernel command
2129 line parameter vsyscall=[native|emulate|none].
2131 On a system with recent enough glibc (2.14 or newer) and no
2132 static binaries, you can say None without a performance penalty
2133 to improve security.
2135 If unsure, select "Emulate".
2137 config LEGACY_VSYSCALL_NATIVE
2140 Actual executable code is located in the fixed vsyscall
2141 address mapping, implementing time() efficiently. Since
2142 this makes the mapping executable, it can be used during
2143 security vulnerability exploitation (traditionally as
2144 ROP gadgets). This configuration is not recommended.
2146 config LEGACY_VSYSCALL_EMULATE
2149 The kernel traps and emulates calls into the fixed
2150 vsyscall address mapping. This makes the mapping
2151 non-executable, but it still contains known contents,
2152 which could be used in certain rare security vulnerability
2153 exploits. This configuration is recommended when userspace
2154 still uses the vsyscall area.
2156 config LEGACY_VSYSCALL_NONE
2159 There will be no vsyscall mapping at all. This will
2160 eliminate any risk of ASLR bypass due to the vsyscall
2161 fixed address mapping. Attempts to use the vsyscalls
2162 will be reported to dmesg, so that either old or
2163 malicious userspace programs can be identified.
2168 bool "Built-in kernel command line"
2170 Allow for specifying boot arguments to the kernel at
2171 build time. On some systems (e.g. embedded ones), it is
2172 necessary or convenient to provide some or all of the
2173 kernel boot arguments with the kernel itself (that is,
2174 to not rely on the boot loader to provide them.)
2176 To compile command line arguments into the kernel,
2177 set this option to 'Y', then fill in the
2178 boot arguments in CONFIG_CMDLINE.
2180 Systems with fully functional boot loaders (i.e. non-embedded)
2181 should leave this option set to 'N'.
2184 string "Built-in kernel command string"
2185 depends on CMDLINE_BOOL
2188 Enter arguments here that should be compiled into the kernel
2189 image and used at boot time. If the boot loader provides a
2190 command line at boot time, it is appended to this string to
2191 form the full kernel command line, when the system boots.
2193 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2194 change this behavior.
2196 In most cases, the command line (whether built-in or provided
2197 by the boot loader) should specify the device for the root
2200 config CMDLINE_OVERRIDE
2201 bool "Built-in command line overrides boot loader arguments"
2202 depends on CMDLINE_BOOL
2204 Set this option to 'Y' to have the kernel ignore the boot loader
2205 command line, and use ONLY the built-in command line.
2207 This is used to work around broken boot loaders. This should
2208 be set to 'N' under normal conditions.
2210 config MODIFY_LDT_SYSCALL
2211 bool "Enable the LDT (local descriptor table)" if EXPERT
2214 Linux can allow user programs to install a per-process x86
2215 Local Descriptor Table (LDT) using the modify_ldt(2) system
2216 call. This is required to run 16-bit or segmented code such as
2217 DOSEMU or some Wine programs. It is also used by some very old
2218 threading libraries.
2220 Enabling this feature adds a small amount of overhead to
2221 context switches and increases the low-level kernel attack
2222 surface. Disabling it removes the modify_ldt(2) system call.
2224 Saying 'N' here may make sense for embedded or server kernels.
2226 source "kernel/livepatch/Kconfig"
2230 config ARCH_ENABLE_MEMORY_HOTPLUG
2232 depends on X86_64 || (X86_32 && HIGHMEM)
2234 config ARCH_ENABLE_MEMORY_HOTREMOVE
2236 depends on MEMORY_HOTPLUG
2238 config USE_PERCPU_NUMA_NODE_ID
2242 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2244 depends on X86_64 || X86_PAE
2246 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2248 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2250 menu "Power management and ACPI options"
2252 config ARCH_HIBERNATION_HEADER
2254 depends on X86_64 && HIBERNATION
2256 source "kernel/power/Kconfig"
2258 source "drivers/acpi/Kconfig"
2260 source "drivers/sfi/Kconfig"
2267 tristate "APM (Advanced Power Management) BIOS support"
2268 depends on X86_32 && PM_SLEEP
2270 APM is a BIOS specification for saving power using several different
2271 techniques. This is mostly useful for battery powered laptops with
2272 APM compliant BIOSes. If you say Y here, the system time will be
2273 reset after a RESUME operation, the /proc/apm device will provide
2274 battery status information, and user-space programs will receive
2275 notification of APM "events" (e.g. battery status change).
2277 If you select "Y" here, you can disable actual use of the APM
2278 BIOS by passing the "apm=off" option to the kernel at boot time.
2280 Note that the APM support is almost completely disabled for
2281 machines with more than one CPU.
2283 In order to use APM, you will need supporting software. For location
2284 and more information, read <file:Documentation/power/apm-acpi.txt>
2285 and the Battery Powered Linux mini-HOWTO, available from
2286 <http://www.tldp.org/docs.html#howto>.
2288 This driver does not spin down disk drives (see the hdparm(8)
2289 manpage ("man 8 hdparm") for that), and it doesn't turn off
2290 VESA-compliant "green" monitors.
2292 This driver does not support the TI 4000M TravelMate and the ACER
2293 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2294 desktop machines also don't have compliant BIOSes, and this driver
2295 may cause those machines to panic during the boot phase.
2297 Generally, if you don't have a battery in your machine, there isn't
2298 much point in using this driver and you should say N. If you get
2299 random kernel OOPSes or reboots that don't seem to be related to
2300 anything, try disabling/enabling this option (or disabling/enabling
2303 Some other things you should try when experiencing seemingly random,
2306 1) make sure that you have enough swap space and that it is
2308 2) pass the "no-hlt" option to the kernel
2309 3) switch on floating point emulation in the kernel and pass
2310 the "no387" option to the kernel
2311 4) pass the "floppy=nodma" option to the kernel
2312 5) pass the "mem=4M" option to the kernel (thereby disabling
2313 all but the first 4 MB of RAM)
2314 6) make sure that the CPU is not over clocked.
2315 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2316 8) disable the cache from your BIOS settings
2317 9) install a fan for the video card or exchange video RAM
2318 10) install a better fan for the CPU
2319 11) exchange RAM chips
2320 12) exchange the motherboard.
2322 To compile this driver as a module, choose M here: the
2323 module will be called apm.
2327 config APM_IGNORE_USER_SUSPEND
2328 bool "Ignore USER SUSPEND"
2330 This option will ignore USER SUSPEND requests. On machines with a
2331 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2332 series notebooks, it is necessary to say Y because of a BIOS bug.
2334 config APM_DO_ENABLE
2335 bool "Enable PM at boot time"
2337 Enable APM features at boot time. From page 36 of the APM BIOS
2338 specification: "When disabled, the APM BIOS does not automatically
2339 power manage devices, enter the Standby State, enter the Suspend
2340 State, or take power saving steps in response to CPU Idle calls."
2341 This driver will make CPU Idle calls when Linux is idle (unless this
2342 feature is turned off -- see "Do CPU IDLE calls", below). This
2343 should always save battery power, but more complicated APM features
2344 will be dependent on your BIOS implementation. You may need to turn
2345 this option off if your computer hangs at boot time when using APM
2346 support, or if it beeps continuously instead of suspending. Turn
2347 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2348 T400CDT. This is off by default since most machines do fine without
2353 bool "Make CPU Idle calls when idle"
2355 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2356 On some machines, this can activate improved power savings, such as
2357 a slowed CPU clock rate, when the machine is idle. These idle calls
2358 are made after the idle loop has run for some length of time (e.g.,
2359 333 mS). On some machines, this will cause a hang at boot time or
2360 whenever the CPU becomes idle. (On machines with more than one CPU,
2361 this option does nothing.)
2363 config APM_DISPLAY_BLANK
2364 bool "Enable console blanking using APM"
2366 Enable console blanking using the APM. Some laptops can use this to
2367 turn off the LCD backlight when the screen blanker of the Linux
2368 virtual console blanks the screen. Note that this is only used by
2369 the virtual console screen blanker, and won't turn off the backlight
2370 when using the X Window system. This also doesn't have anything to
2371 do with your VESA-compliant power-saving monitor. Further, this
2372 option doesn't work for all laptops -- it might not turn off your
2373 backlight at all, or it might print a lot of errors to the console,
2374 especially if you are using gpm.
2376 config APM_ALLOW_INTS
2377 bool "Allow interrupts during APM BIOS calls"
2379 Normally we disable external interrupts while we are making calls to
2380 the APM BIOS as a measure to lessen the effects of a badly behaving
2381 BIOS implementation. The BIOS should reenable interrupts if it
2382 needs to. Unfortunately, some BIOSes do not -- especially those in
2383 many of the newer IBM Thinkpads. If you experience hangs when you
2384 suspend, try setting this to Y. Otherwise, say N.
2388 source "drivers/cpufreq/Kconfig"
2390 source "drivers/cpuidle/Kconfig"
2392 source "drivers/idle/Kconfig"
2397 menu "Bus options (PCI etc.)"
2403 Find out whether you have a PCI motherboard. PCI is the name of a
2404 bus system, i.e. the way the CPU talks to the other stuff inside
2405 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2406 VESA. If you have PCI, say Y, otherwise N.
2409 prompt "PCI access mode"
2410 depends on X86_32 && PCI
2413 On PCI systems, the BIOS can be used to detect the PCI devices and
2414 determine their configuration. However, some old PCI motherboards
2415 have BIOS bugs and may crash if this is done. Also, some embedded
2416 PCI-based systems don't have any BIOS at all. Linux can also try to
2417 detect the PCI hardware directly without using the BIOS.
2419 With this option, you can specify how Linux should detect the
2420 PCI devices. If you choose "BIOS", the BIOS will be used,
2421 if you choose "Direct", the BIOS won't be used, and if you
2422 choose "MMConfig", then PCI Express MMCONFIG will be used.
2423 If you choose "Any", the kernel will try MMCONFIG, then the
2424 direct access method and falls back to the BIOS if that doesn't
2425 work. If unsure, go with the default, which is "Any".
2430 config PCI_GOMMCONFIG
2447 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2449 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2452 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2456 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2460 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2464 depends on PCI && XEN
2472 bool "Support mmconfig PCI config space access"
2473 depends on X86_64 && PCI && ACPI
2475 config PCI_CNB20LE_QUIRK
2476 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2479 Read the PCI windows out of the CNB20LE host bridge. This allows
2480 PCI hotplug to work on systems with the CNB20LE chipset which do
2483 There's no public spec for this chipset, and this functionality
2484 is known to be incomplete.
2486 You should say N unless you know you need this.
2488 source "drivers/pci/Kconfig"
2491 bool "ISA-style bus support on modern systems" if EXPERT
2494 Enables ISA-style drivers on modern systems. This is necessary to
2495 support PC/104 devices on X86_64 platforms.
2499 # x86_64 have no ISA slots, but can have ISA-style DMA.
2501 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2504 Enables ISA-style DMA support for devices requiring such controllers.
2512 Find out whether you have ISA slots on your motherboard. ISA is the
2513 name of a bus system, i.e. the way the CPU talks to the other stuff
2514 inside your box. Other bus systems are PCI, EISA, MicroChannel
2515 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2516 newer boards don't support it. If you have ISA, say Y, otherwise N.
2522 The Extended Industry Standard Architecture (EISA) bus was
2523 developed as an open alternative to the IBM MicroChannel bus.
2525 The EISA bus provided some of the features of the IBM MicroChannel
2526 bus while maintaining backward compatibility with cards made for
2527 the older ISA bus. The EISA bus saw limited use between 1988 and
2528 1995 when it was made obsolete by the PCI bus.
2530 Say Y here if you are building a kernel for an EISA-based machine.
2534 source "drivers/eisa/Kconfig"
2537 tristate "NatSemi SCx200 support"
2539 This provides basic support for National Semiconductor's
2540 (now AMD's) Geode processors. The driver probes for the
2541 PCI-IDs of several on-chip devices, so its a good dependency
2542 for other scx200_* drivers.
2544 If compiled as a module, the driver is named scx200.
2546 config SCx200HR_TIMER
2547 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2551 This driver provides a clocksource built upon the on-chip
2552 27MHz high-resolution timer. Its also a workaround for
2553 NSC Geode SC-1100's buggy TSC, which loses time when the
2554 processor goes idle (as is done by the scheduler). The
2555 other workaround is idle=poll boot option.
2558 bool "One Laptop Per Child support"
2565 Add support for detecting the unique features of the OLPC
2569 bool "OLPC XO-1 Power Management"
2570 depends on OLPC && MFD_CS5535 && PM_SLEEP
2573 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2576 bool "OLPC XO-1 Real Time Clock"
2577 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2579 Add support for the XO-1 real time clock, which can be used as a
2580 programmable wakeup source.
2583 bool "OLPC XO-1 SCI extras"
2584 depends on OLPC && OLPC_XO1_PM
2590 Add support for SCI-based features of the OLPC XO-1 laptop:
2591 - EC-driven system wakeups
2595 - AC adapter status updates
2596 - Battery status updates
2598 config OLPC_XO15_SCI
2599 bool "OLPC XO-1.5 SCI extras"
2600 depends on OLPC && ACPI
2603 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2604 - EC-driven system wakeups
2605 - AC adapter status updates
2606 - Battery status updates
2609 bool "PCEngines ALIX System Support (LED setup)"
2612 This option enables system support for the PCEngines ALIX.
2613 At present this just sets up LEDs for GPIO control on
2614 ALIX2/3/6 boards. However, other system specific setup should
2617 Note: You must still enable the drivers for GPIO and LED support
2618 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2620 Note: You have to set alix.force=1 for boards with Award BIOS.
2623 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2626 This option enables system support for the Soekris Engineering net5501.
2629 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2633 This option enables system support for the Traverse Technologies GEOS.
2636 bool "Technologic Systems TS-5500 platform support"
2638 select CHECK_SIGNATURE
2642 This option enables system support for the Technologic Systems TS-5500.
2648 depends on CPU_SUP_AMD && PCI
2650 source "drivers/pcmcia/Kconfig"
2653 tristate "RapidIO support"
2657 If enabled this option will include drivers and the core
2658 infrastructure code to support RapidIO interconnect devices.
2660 source "drivers/rapidio/Kconfig"
2663 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2665 Firmwares often provide initial graphics framebuffers so the BIOS,
2666 bootloader or kernel can show basic video-output during boot for
2667 user-guidance and debugging. Historically, x86 used the VESA BIOS
2668 Extensions and EFI-framebuffers for this, which are mostly limited
2670 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2671 framebuffers so the new generic system-framebuffer drivers can be
2672 used on x86. If the framebuffer is not compatible with the generic
2673 modes, it is adverticed as fallback platform framebuffer so legacy
2674 drivers like efifb, vesafb and uvesafb can pick it up.
2675 If this option is not selected, all system framebuffers are always
2676 marked as fallback platform framebuffers as usual.
2678 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2679 not be able to pick up generic system framebuffers if this option
2680 is selected. You are highly encouraged to enable simplefb as
2681 replacement if you select this option. simplefb can correctly deal
2682 with generic system framebuffers. But you should still keep vesafb
2683 and others enabled as fallback if a system framebuffer is
2684 incompatible with simplefb.
2691 menu "Executable file formats / Emulations"
2693 source "fs/Kconfig.binfmt"
2695 config IA32_EMULATION
2696 bool "IA32 Emulation"
2699 select COMPAT_BINFMT_ELF
2700 select ARCH_WANT_OLD_COMPAT_IPC
2702 Include code to run legacy 32-bit programs under a
2703 64-bit kernel. You should likely turn this on, unless you're
2704 100% sure that you don't have any 32-bit programs left.
2707 tristate "IA32 a.out support"
2708 depends on IA32_EMULATION
2710 Support old a.out binaries in the 32bit emulation.
2713 bool "x32 ABI for 64-bit mode"
2716 Include code to run binaries for the x32 native 32-bit ABI
2717 for 64-bit processors. An x32 process gets access to the
2718 full 64-bit register file and wide data path while leaving
2719 pointers at 32 bits for smaller memory footprint.
2721 You will need a recent binutils (2.22 or later) with
2722 elf32_x86_64 support enabled to compile a kernel with this
2727 depends on IA32_EMULATION || X86_X32
2730 config COMPAT_FOR_U64_ALIGNMENT
2733 config SYSVIPC_COMPAT
2745 config HAVE_ATOMIC_IOMAP
2749 config X86_DEV_DMA_OPS
2751 depends on X86_64 || STA2X11
2753 config X86_DMA_REMAP
2761 source "net/Kconfig"
2763 source "drivers/Kconfig"
2765 source "drivers/firmware/Kconfig"
2769 source "arch/x86/Kconfig.debug"
2771 source "security/Kconfig"
2773 source "crypto/Kconfig"
2775 source "arch/x86/kvm/Kconfig"
2777 source "lib/Kconfig"