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_WANT_BATCHED_UNMAP_TLB_FLUSH
45 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
46 select ARCH_WANT_FRAME_POINTERS
47 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
48 select ARCH_WANT_OPTIONAL_GPIOLIB
49 select BUILDTIME_EXTABLE_SORT
51 select CLKSRC_I8253 if X86_32
52 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
53 select CLOCKSOURCE_WATCHDOG
54 select CLONE_BACKWARDS if X86_32
55 select COMPAT_OLD_SIGACTION if IA32_EMULATION
56 select DCACHE_WORD_ACCESS
57 select EDAC_ATOMIC_SCRUB
59 select GENERIC_CLOCKEVENTS
60 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
61 select GENERIC_CLOCKEVENTS_MIN_ADJUST
62 select GENERIC_CMOS_UPDATE
63 select GENERIC_CPU_AUTOPROBE
64 select GENERIC_CPU_VULNERABILITIES
65 select GENERIC_EARLY_IOREMAP
66 select GENERIC_FIND_FIRST_BIT
68 select GENERIC_IRQ_PROBE
69 select GENERIC_IRQ_SHOW
70 select GENERIC_PENDING_IRQ if SMP
71 select GENERIC_SMP_IDLE_THREAD
72 select GENERIC_STRNCPY_FROM_USER
73 select GENERIC_STRNLEN_USER
74 select GENERIC_TIME_VSYSCALL
75 select HAVE_ACPI_APEI if ACPI
76 select HAVE_ACPI_APEI_NMI if ACPI
77 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
78 select HAVE_AOUT if X86_32
79 select HAVE_ARCH_AUDITSYSCALL
80 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
81 select HAVE_ARCH_JUMP_LABEL
82 select HAVE_ARCH_KASAN if X86_64 && SPARSEMEM_VMEMMAP
84 select HAVE_ARCH_KMEMCHECK
85 select HAVE_ARCH_SECCOMP_FILTER
86 select HAVE_ARCH_SOFT_DIRTY if X86_64
87 select HAVE_ARCH_TRACEHOOK
88 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
89 select HAVE_BPF_JIT if X86_64
90 select HAVE_EBPF_JIT if X86_64
91 select HAVE_CC_STACKPROTECTOR
92 select HAVE_CMPXCHG_DOUBLE
93 select HAVE_CMPXCHG_LOCAL
94 select HAVE_CONTEXT_TRACKING if X86_64
95 select HAVE_COPY_THREAD_TLS
96 select HAVE_C_RECORDMCOUNT
97 select HAVE_DEBUG_KMEMLEAK
98 select HAVE_DEBUG_STACKOVERFLOW
99 select HAVE_DMA_API_DEBUG
100 select HAVE_DMA_ATTRS
101 select HAVE_DMA_CONTIGUOUS
102 select HAVE_DYNAMIC_FTRACE
103 select HAVE_DYNAMIC_FTRACE_WITH_REGS
104 select HAVE_EFFICIENT_UNALIGNED_ACCESS
105 select HAVE_FENTRY if X86_64
106 select HAVE_FTRACE_MCOUNT_RECORD
107 select HAVE_FUNCTION_GRAPH_FP_TEST
108 select HAVE_FUNCTION_GRAPH_TRACER
109 select HAVE_FUNCTION_TRACER
110 select HAVE_GENERIC_DMA_COHERENT if X86_32
111 select HAVE_HW_BREAKPOINT
113 select HAVE_IOREMAP_PROT
114 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
115 select HAVE_IRQ_TIME_ACCOUNTING
116 select HAVE_KERNEL_BZIP2
117 select HAVE_KERNEL_GZIP
118 select HAVE_KERNEL_LZ4
119 select HAVE_KERNEL_LZMA
120 select HAVE_KERNEL_LZO
121 select HAVE_KERNEL_XZ
123 select HAVE_KPROBES_ON_FTRACE
124 select HAVE_KRETPROBES
126 select HAVE_LIVEPATCH if X86_64
128 select HAVE_MEMBLOCK_NODE_MAP
129 select HAVE_MIXED_BREAKPOINTS_REGS
131 select HAVE_OPTPROBES
132 select HAVE_PCSPKR_PLATFORM
133 select HAVE_PERF_EVENTS
134 select HAVE_PERF_EVENTS_NMI
135 select HAVE_PERF_REGS
136 select HAVE_PERF_USER_STACK_DUMP
137 select HAVE_REGS_AND_STACK_ACCESS_API
138 select HAVE_SYSCALL_TRACEPOINTS
139 select HAVE_UID16 if X86_32 || IA32_EMULATION
140 select HAVE_UNSTABLE_SCHED_CLOCK
141 select HAVE_USER_RETURN_NOTIFIER
142 select IRQ_FORCED_THREADING
143 select MODULES_USE_ELF_RELA if X86_64
144 select MODULES_USE_ELF_REL if X86_32
145 select OLD_SIGACTION if X86_32
146 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
151 select SYSCTL_EXCEPTION_TRACE
152 select USER_STACKTRACE_SUPPORT
154 select X86_DEV_DMA_OPS if X86_64
155 select X86_FEATURE_NAMES if PROC_FS
157 config INSTRUCTION_DECODER
159 depends on KPROBES || PERF_EVENTS || UPROBES
161 config PERF_EVENTS_INTEL_UNCORE
163 depends on PERF_EVENTS && CPU_SUP_INTEL && PCI
167 default "elf32-i386" if X86_32
168 default "elf64-x86-64" if X86_64
170 config ARCH_DEFCONFIG
172 default "arch/x86/configs/i386_defconfig" if X86_32
173 default "arch/x86/configs/x86_64_defconfig" if X86_64
175 config LOCKDEP_SUPPORT
178 config STACKTRACE_SUPPORT
181 config HAVE_LATENCYTOP_SUPPORT
190 config NEED_DMA_MAP_STATE
192 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
194 config NEED_SG_DMA_LENGTH
197 config GENERIC_ISA_DMA
199 depends on ISA_DMA_API
204 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
206 config GENERIC_BUG_RELATIVE_POINTERS
209 config GENERIC_HWEIGHT
212 config ARCH_MAY_HAVE_PC_FDC
214 depends on ISA_DMA_API
216 config RWSEM_XCHGADD_ALGORITHM
219 config GENERIC_CALIBRATE_DELAY
222 config ARCH_HAS_CPU_RELAX
225 config ARCH_HAS_CACHE_LINE_SIZE
228 config HAVE_SETUP_PER_CPU_AREA
231 config NEED_PER_CPU_EMBED_FIRST_CHUNK
234 config NEED_PER_CPU_PAGE_FIRST_CHUNK
237 config ARCH_HIBERNATION_POSSIBLE
240 config ARCH_SUSPEND_POSSIBLE
243 config ARCH_WANT_HUGE_PMD_SHARE
246 config ARCH_WANT_GENERAL_HUGETLB
255 config ARCH_SUPPORTS_OPTIMIZED_INLINING
258 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
261 config KASAN_SHADOW_OFFSET
264 default 0xdffffc0000000000
266 config HAVE_INTEL_TXT
268 depends on INTEL_IOMMU && ACPI
272 depends on X86_32 && SMP
276 depends on X86_64 && SMP
278 config X86_32_LAZY_GS
280 depends on X86_32 && !CC_STACKPROTECTOR
282 config ARCH_SUPPORTS_UPROBES
285 config FIX_EARLYCON_MEM
288 config PGTABLE_LEVELS
294 source "init/Kconfig"
295 source "kernel/Kconfig.freezer"
297 menu "Processor type and features"
300 bool "DMA memory allocation support" if EXPERT
303 DMA memory allocation support allows devices with less than 32-bit
304 addressing to allocate within the first 16MB of address space.
305 Disable if no such devices will be used.
310 bool "Symmetric multi-processing support"
312 This enables support for systems with more than one CPU. If you have
313 a system with only one CPU, say N. If you have a system with more
316 If you say N here, the kernel will run on uni- and multiprocessor
317 machines, but will use only one CPU of a multiprocessor machine. If
318 you say Y here, the kernel will run on many, but not all,
319 uniprocessor machines. On a uniprocessor machine, the kernel
320 will run faster if you say N here.
322 Note that if you say Y here and choose architecture "586" or
323 "Pentium" under "Processor family", the kernel will not work on 486
324 architectures. Similarly, multiprocessor kernels for the "PPro"
325 architecture may not work on all Pentium based boards.
327 People using multiprocessor machines who say Y here should also say
328 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
329 Management" code will be disabled if you say Y here.
331 See also <file:Documentation/x86/i386/IO-APIC.txt>,
332 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
333 <http://www.tldp.org/docs.html#howto>.
335 If you don't know what to do here, say N.
337 config X86_FEATURE_NAMES
338 bool "Processor feature human-readable names" if EMBEDDED
341 This option compiles in a table of x86 feature bits and corresponding
342 names. This is required to support /proc/cpuinfo and a few kernel
343 messages. You can disable this to save space, at the expense of
344 making those few kernel messages show numeric feature bits instead.
348 config X86_FAST_FEATURE_TESTS
349 bool "Fast CPU feature tests" if EMBEDDED
352 Some fast-paths in the kernel depend on the capabilities of the CPU.
353 Say Y here for the kernel to patch in the appropriate code at runtime
354 based on the capabilities of the CPU. The infrastructure for patching
355 code at runtime takes up some additional space; space-constrained
356 embedded systems may wish to say N here to produce smaller, slightly
360 bool "Support x2apic"
361 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
363 This enables x2apic support on CPUs that have this feature.
365 This allows 32-bit apic IDs (so it can support very large systems),
366 and accesses the local apic via MSRs not via mmio.
368 If you don't know what to do here, say N.
371 bool "Enable MPS table" if ACPI || SFI
373 depends on X86_LOCAL_APIC
375 For old smp systems that do not have proper acpi support. Newer systems
376 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
379 bool "Support for big SMP systems with more than 8 CPUs"
380 depends on X86_32 && SMP
382 This option is needed for the systems that have more than 8 CPUs
386 depends on X86_GOLDFISH
389 bool "Avoid speculative indirect branches in kernel"
392 Compile kernel with the retpoline compiler options to guard against
393 kernel-to-user data leaks by avoiding speculative indirect
394 branches. Requires a compiler with -mindirect-branch=thunk-extern
395 support for full protection. The kernel may run slower.
397 Without compiler support, at least indirect branches in assembler
398 code are eliminated. Since this includes the syscall entry path,
399 it is not entirely pointless.
402 config X86_EXTENDED_PLATFORM
403 bool "Support for extended (non-PC) x86 platforms"
406 If you disable this option then the kernel will only support
407 standard PC platforms. (which covers the vast majority of
410 If you enable this option then you'll be able to select support
411 for the following (non-PC) 32 bit x86 platforms:
412 Goldfish (Android emulator)
415 SGI 320/540 (Visual Workstation)
416 STA2X11-based (e.g. Northville)
417 Moorestown MID devices
419 If you have one of these systems, or if you want to build a
420 generic distribution kernel, say Y here - otherwise say N.
424 config X86_EXTENDED_PLATFORM
425 bool "Support for extended (non-PC) x86 platforms"
428 If you disable this option then the kernel will only support
429 standard PC platforms. (which covers the vast majority of
432 If you enable this option then you'll be able to select support
433 for the following (non-PC) 64 bit x86 platforms:
438 If you have one of these systems, or if you want to build a
439 generic distribution kernel, say Y here - otherwise say N.
441 # This is an alphabetically sorted list of 64 bit extended platforms
442 # Please maintain the alphabetic order if and when there are additions
444 bool "Numascale NumaChip"
446 depends on X86_EXTENDED_PLATFORM
449 depends on X86_X2APIC
450 depends on PCI_MMCONFIG
452 Adds support for Numascale NumaChip large-SMP systems. Needed to
453 enable more than ~168 cores.
454 If you don't have one of these, you should say N here.
458 select HYPERVISOR_GUEST
460 depends on X86_64 && PCI
461 depends on X86_EXTENDED_PLATFORM
464 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
465 supposed to run on these EM64T-based machines. Only choose this option
466 if you have one of these machines.
469 bool "SGI Ultraviolet"
471 depends on X86_EXTENDED_PLATFORM
473 depends on X86_X2APIC
476 This option is needed in order to support SGI Ultraviolet systems.
477 If you don't have one of these, you should say N here.
479 # Following is an alphabetically sorted list of 32 bit extended platforms
480 # Please maintain the alphabetic order if and when there are additions
483 bool "Goldfish (Virtual Platform)"
484 depends on X86_EXTENDED_PLATFORM
486 Enable support for the Goldfish virtual platform used primarily
487 for Android development. Unless you are building for the Android
488 Goldfish emulator say N here.
491 bool "CE4100 TV platform"
493 depends on PCI_GODIRECT
494 depends on X86_IO_APIC
496 depends on X86_EXTENDED_PLATFORM
497 select X86_REBOOTFIXUPS
499 select OF_EARLY_FLATTREE
501 Select for the Intel CE media processor (CE4100) SOC.
502 This option compiles in support for the CE4100 SOC for settop
503 boxes and media devices.
506 bool "Intel MID platform support"
508 depends on X86_EXTENDED_PLATFORM
509 depends on X86_PLATFORM_DEVICES
512 depends on X86_IO_APIC
518 select MFD_INTEL_MSIC
520 Select to build a kernel capable of supporting Intel MID (Mobile
521 Internet Device) platform systems which do not have the PCI legacy
522 interfaces. If you are building for a PC class system say N here.
524 Intel MID platforms are based on an Intel processor and chipset which
525 consume less power than most of the x86 derivatives.
527 config X86_INTEL_QUARK
528 bool "Intel Quark platform support"
530 depends on X86_EXTENDED_PLATFORM
531 depends on X86_PLATFORM_DEVICES
535 depends on X86_IO_APIC
540 Select to include support for Quark X1000 SoC.
541 Say Y here if you have a Quark based system such as the Arduino
542 compatible Intel Galileo.
544 config X86_INTEL_LPSS
545 bool "Intel Low Power Subsystem Support"
550 Select to build support for Intel Low Power Subsystem such as
551 found on Intel Lynxpoint PCH. Selecting this option enables
552 things like clock tree (common clock framework) and pincontrol
553 which are needed by the LPSS peripheral drivers.
555 config X86_AMD_PLATFORM_DEVICE
556 bool "AMD ACPI2Platform devices support"
561 Select to interpret AMD specific ACPI device to platform device
562 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
563 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
564 implemented under PINCTRL subsystem.
567 tristate "Intel SoC IOSF Sideband support for SoC platforms"
570 This option enables sideband register access support for Intel SoC
571 platforms. On these platforms the IOSF sideband is used in lieu of
572 MSR's for some register accesses, mostly but not limited to thermal
573 and power. Drivers may query the availability of this device to
574 determine if they need the sideband in order to work on these
575 platforms. The sideband is available on the following SoC products.
576 This list is not meant to be exclusive.
581 You should say Y if you are running a kernel on one of these SoC's.
583 config IOSF_MBI_DEBUG
584 bool "Enable IOSF sideband access through debugfs"
585 depends on IOSF_MBI && DEBUG_FS
587 Select this option to expose the IOSF sideband access registers (MCR,
588 MDR, MCRX) through debugfs to write and read register information from
589 different units on the SoC. This is most useful for obtaining device
590 state information for debug and analysis. As this is a general access
591 mechanism, users of this option would have specific knowledge of the
592 device they want to access.
594 If you don't require the option or are in doubt, say N.
597 bool "RDC R-321x SoC"
599 depends on X86_EXTENDED_PLATFORM
601 select X86_REBOOTFIXUPS
603 This option is needed for RDC R-321x system-on-chip, also known
605 If you don't have one of these chips, you should say N here.
607 config X86_32_NON_STANDARD
608 bool "Support non-standard 32-bit SMP architectures"
609 depends on X86_32 && SMP
610 depends on X86_EXTENDED_PLATFORM
612 This option compiles in the bigsmp and STA2X11 default
613 subarchitectures. It is intended for a generic binary
614 kernel. If you select them all, kernel will probe it one by
615 one and will fallback to default.
617 # Alphabetically sorted list of Non standard 32 bit platforms
619 config X86_SUPPORTS_MEMORY_FAILURE
621 # MCE code calls memory_failure():
623 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
624 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
625 depends on X86_64 || !SPARSEMEM
626 select ARCH_SUPPORTS_MEMORY_FAILURE
629 bool "STA2X11 Companion Chip Support"
630 depends on X86_32_NON_STANDARD && PCI
631 select X86_DEV_DMA_OPS
635 select ARCH_REQUIRE_GPIOLIB
638 This adds support for boards based on the STA2X11 IO-Hub,
639 a.k.a. "ConneXt". The chip is used in place of the standard
640 PC chipset, so all "standard" peripherals are missing. If this
641 option is selected the kernel will still be able to boot on
642 standard PC machines.
645 tristate "Eurobraille/Iris poweroff module"
648 The Iris machines from EuroBraille do not have APM or ACPI support
649 to shut themselves down properly. A special I/O sequence is
650 needed to do so, which is what this module does at
653 This is only for Iris machines from EuroBraille.
657 config SCHED_OMIT_FRAME_POINTER
659 prompt "Single-depth WCHAN output"
662 Calculate simpler /proc/<PID>/wchan values. If this option
663 is disabled then wchan values will recurse back to the
664 caller function. This provides more accurate wchan values,
665 at the expense of slightly more scheduling overhead.
667 If in doubt, say "Y".
669 menuconfig HYPERVISOR_GUEST
670 bool "Linux guest support"
672 Say Y here to enable options for running Linux under various hyper-
673 visors. This option enables basic hypervisor detection and platform
676 If you say N, all options in this submenu will be skipped and
677 disabled, and Linux guest support won't be built in.
682 bool "Enable paravirtualization code"
684 This changes the kernel so it can modify itself when it is run
685 under a hypervisor, potentially improving performance significantly
686 over full virtualization. However, when run without a hypervisor
687 the kernel is theoretically slower and slightly larger.
689 config PARAVIRT_DEBUG
690 bool "paravirt-ops debugging"
691 depends on PARAVIRT && DEBUG_KERNEL
693 Enable to debug paravirt_ops internals. Specifically, BUG if
694 a paravirt_op is missing when it is called.
696 config PARAVIRT_SPINLOCKS
697 bool "Paravirtualization layer for spinlocks"
698 depends on PARAVIRT && SMP
699 select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS
701 Paravirtualized spinlocks allow a pvops backend to replace the
702 spinlock implementation with something virtualization-friendly
703 (for example, block the virtual CPU rather than spinning).
705 It has a minimal impact on native kernels and gives a nice performance
706 benefit on paravirtualized KVM / Xen kernels.
708 If you are unsure how to answer this question, answer Y.
710 source "arch/x86/xen/Kconfig"
713 bool "KVM Guest support (including kvmclock)"
715 select PARAVIRT_CLOCK
718 This option enables various optimizations for running under the KVM
719 hypervisor. It includes a paravirtualized clock, so that instead
720 of relying on a PIT (or probably other) emulation by the
721 underlying device model, the host provides the guest with
722 timing infrastructure such as time of day, and system time
725 bool "Enable debug information for KVM Guests in debugfs"
726 depends on KVM_GUEST && DEBUG_FS
729 This option enables collection of various statistics for KVM guest.
730 Statistics are displayed in debugfs filesystem. Enabling this option
731 may incur significant overhead.
733 source "arch/x86/lguest/Kconfig"
735 config PARAVIRT_TIME_ACCOUNTING
736 bool "Paravirtual steal time accounting"
740 Select this option to enable fine granularity task steal time
741 accounting. Time spent executing other tasks in parallel with
742 the current vCPU is discounted from the vCPU power. To account for
743 that, there can be a small performance impact.
745 If in doubt, say N here.
747 config PARAVIRT_CLOCK
750 endif #HYPERVISOR_GUEST
755 source "arch/x86/Kconfig.cpu"
759 prompt "HPET Timer Support" if X86_32
761 Use the IA-PC HPET (High Precision Event Timer) to manage
762 time in preference to the PIT and RTC, if a HPET is
764 HPET is the next generation timer replacing legacy 8254s.
765 The HPET provides a stable time base on SMP
766 systems, unlike the TSC, but it is more expensive to access,
767 as it is off-chip. You can find the HPET spec at
768 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
770 You can safely choose Y here. However, HPET will only be
771 activated if the platform and the BIOS support this feature.
772 Otherwise the 8254 will be used for timing services.
774 Choose N to continue using the legacy 8254 timer.
776 config HPET_EMULATE_RTC
778 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
781 def_bool y if X86_INTEL_MID
782 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
784 depends on X86_INTEL_MID && SFI
786 APB timer is the replacement for 8254, HPET on X86 MID platforms.
787 The APBT provides a stable time base on SMP
788 systems, unlike the TSC, but it is more expensive to access,
789 as it is off-chip. APB timers are always running regardless of CPU
790 C states, they are used as per CPU clockevent device when possible.
792 # Mark as expert because too many people got it wrong.
793 # The code disables itself when not needed.
796 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
797 bool "Enable DMI scanning" if EXPERT
799 Enabled scanning of DMI to identify machine quirks. Say Y
800 here unless you have verified that your setup is not
801 affected by entries in the DMI blacklist. Required by PNP
805 bool "Old AMD GART IOMMU support"
807 depends on X86_64 && PCI && AMD_NB
809 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
810 GART based hardware IOMMUs.
812 The GART supports full DMA access for devices with 32-bit access
813 limitations, on systems with more than 3 GB. This is usually needed
814 for USB, sound, many IDE/SATA chipsets and some other devices.
816 Newer systems typically have a modern AMD IOMMU, supported via
817 the CONFIG_AMD_IOMMU=y config option.
819 In normal configurations this driver is only active when needed:
820 there's more than 3 GB of memory and the system contains a
821 32-bit limited device.
826 bool "IBM Calgary IOMMU support"
828 depends on X86_64 && PCI
830 Support for hardware IOMMUs in IBM's xSeries x366 and x460
831 systems. Needed to run systems with more than 3GB of memory
832 properly with 32-bit PCI devices that do not support DAC
833 (Double Address Cycle). Calgary also supports bus level
834 isolation, where all DMAs pass through the IOMMU. This
835 prevents them from going anywhere except their intended
836 destination. This catches hard-to-find kernel bugs and
837 mis-behaving drivers and devices that do not use the DMA-API
838 properly to set up their DMA buffers. The IOMMU can be
839 turned off at boot time with the iommu=off parameter.
840 Normally the kernel will make the right choice by itself.
843 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
845 prompt "Should Calgary be enabled by default?"
846 depends on CALGARY_IOMMU
848 Should Calgary be enabled by default? if you choose 'y', Calgary
849 will be used (if it exists). If you choose 'n', Calgary will not be
850 used even if it exists. If you choose 'n' and would like to use
851 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
854 # need this always selected by IOMMU for the VIA workaround
858 Support for software bounce buffers used on x86-64 systems
859 which don't have a hardware IOMMU. Using this PCI devices
860 which can only access 32-bits of memory can be used on systems
861 with more than 3 GB of memory.
866 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
869 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
870 depends on X86_64 && SMP && DEBUG_KERNEL
871 select CPUMASK_OFFSTACK
873 Enable maximum number of CPUS and NUMA Nodes for this architecture.
877 int "Maximum number of CPUs" if SMP && !MAXSMP
878 range 2 8 if SMP && X86_32 && !X86_BIGSMP
879 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
880 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
882 default "8192" if MAXSMP
883 default "32" if SMP && X86_BIGSMP
884 default "8" if SMP && X86_32
887 This allows you to specify the maximum number of CPUs which this
888 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
889 supported value is 8192, otherwise the maximum value is 512. The
890 minimum value which makes sense is 2.
892 This is purely to save memory - each supported CPU adds
893 approximately eight kilobytes to the kernel image.
900 prompt "Multi-core scheduler support"
903 Multi-core scheduler support improves the CPU scheduler's decision
904 making when dealing with multi-core CPU chips at a cost of slightly
905 increased overhead in some places. If unsure say N here.
907 source "kernel/Kconfig.preempt"
911 depends on !SMP && X86_LOCAL_APIC
914 bool "Local APIC support on uniprocessors" if !PCI_MSI
916 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
918 A local APIC (Advanced Programmable Interrupt Controller) is an
919 integrated interrupt controller in the CPU. If you have a single-CPU
920 system which has a processor with a local APIC, you can say Y here to
921 enable and use it. If you say Y here even though your machine doesn't
922 have a local APIC, then the kernel will still run with no slowdown at
923 all. The local APIC supports CPU-generated self-interrupts (timer,
924 performance counters), and the NMI watchdog which detects hard
928 bool "IO-APIC support on uniprocessors"
929 depends on X86_UP_APIC
931 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
932 SMP-capable replacement for PC-style interrupt controllers. Most
933 SMP systems and many recent uniprocessor systems have one.
935 If you have a single-CPU system with an IO-APIC, you can say Y here
936 to use it. If you say Y here even though your machine doesn't have
937 an IO-APIC, then the kernel will still run with no slowdown at all.
939 config X86_LOCAL_APIC
941 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
942 select IRQ_DOMAIN_HIERARCHY
943 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
947 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
949 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
950 bool "Reroute for broken boot IRQs"
951 depends on X86_IO_APIC
953 This option enables a workaround that fixes a source of
954 spurious interrupts. This is recommended when threaded
955 interrupt handling is used on systems where the generation of
956 superfluous "boot interrupts" cannot be disabled.
958 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
959 entry in the chipset's IO-APIC is masked (as, e.g. the RT
960 kernel does during interrupt handling). On chipsets where this
961 boot IRQ generation cannot be disabled, this workaround keeps
962 the original IRQ line masked so that only the equivalent "boot
963 IRQ" is delivered to the CPUs. The workaround also tells the
964 kernel to set up the IRQ handler on the boot IRQ line. In this
965 way only one interrupt is delivered to the kernel. Otherwise
966 the spurious second interrupt may cause the kernel to bring
967 down (vital) interrupt lines.
969 Only affects "broken" chipsets. Interrupt sharing may be
970 increased on these systems.
973 bool "Machine Check / overheating reporting"
974 select GENERIC_ALLOCATOR
977 Machine Check support allows the processor to notify the
978 kernel if it detects a problem (e.g. overheating, data corruption).
979 The action the kernel takes depends on the severity of the problem,
980 ranging from warning messages to halting the machine.
984 prompt "Intel MCE features"
985 depends on X86_MCE && X86_LOCAL_APIC
987 Additional support for intel specific MCE features such as
992 prompt "AMD MCE features"
993 depends on X86_MCE && X86_LOCAL_APIC
995 Additional support for AMD specific MCE features such as
996 the DRAM Error Threshold.
998 config X86_ANCIENT_MCE
999 bool "Support for old Pentium 5 / WinChip machine checks"
1000 depends on X86_32 && X86_MCE
1002 Include support for machine check handling on old Pentium 5 or WinChip
1003 systems. These typically need to be enabled explicitly on the command
1006 config X86_MCE_THRESHOLD
1007 depends on X86_MCE_AMD || X86_MCE_INTEL
1010 config X86_MCE_INJECT
1011 depends on X86_MCE && X86_LOCAL_APIC
1012 tristate "Machine check injector support"
1014 Provide support for injecting machine checks for testing purposes.
1015 If you don't know what a machine check is and you don't do kernel
1016 QA it is safe to say n.
1018 config X86_THERMAL_VECTOR
1020 depends on X86_MCE_INTEL
1022 config X86_LEGACY_VM86
1023 bool "Legacy VM86 support"
1027 This option allows user programs to put the CPU into V8086
1028 mode, which is an 80286-era approximation of 16-bit real mode.
1030 Some very old versions of X and/or vbetool require this option
1031 for user mode setting. Similarly, DOSEMU will use it if
1032 available to accelerate real mode DOS programs. However, any
1033 recent version of DOSEMU, X, or vbetool should be fully
1034 functional even without kernel VM86 support, as they will all
1035 fall back to software emulation. Nevertheless, if you are using
1036 a 16-bit DOS program where 16-bit performance matters, vm86
1037 mode might be faster than emulation and you might want to
1040 Note that any app that works on a 64-bit kernel is unlikely to
1041 need this option, as 64-bit kernels don't, and can't, support
1042 V8086 mode. This option is also unrelated to 16-bit protected
1043 mode and is not needed to run most 16-bit programs under Wine.
1045 Enabling this option increases the complexity of the kernel
1046 and slows down exception handling a tiny bit.
1048 If unsure, say N here.
1052 default X86_LEGACY_VM86
1055 bool "Enable support for 16-bit segments" if EXPERT
1057 depends on MODIFY_LDT_SYSCALL
1059 This option is required by programs like Wine to run 16-bit
1060 protected mode legacy code on x86 processors. Disabling
1061 this option saves about 300 bytes on i386, or around 6K text
1062 plus 16K runtime memory on x86-64,
1066 depends on X86_16BIT && X86_32
1070 depends on X86_16BIT && X86_64
1072 config X86_VSYSCALL_EMULATION
1073 bool "Enable vsyscall emulation" if EXPERT
1077 This enables emulation of the legacy vsyscall page. Disabling
1078 it is roughly equivalent to booting with vsyscall=none, except
1079 that it will also disable the helpful warning if a program
1080 tries to use a vsyscall. With this option set to N, offending
1081 programs will just segfault, citing addresses of the form
1084 This option is required by many programs built before 2013, and
1085 care should be used even with newer programs if set to N.
1087 Disabling this option saves about 7K of kernel size and
1088 possibly 4K of additional runtime pagetable memory.
1091 tristate "Toshiba Laptop support"
1094 This adds a driver to safely access the System Management Mode of
1095 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1096 not work on models with a Phoenix BIOS. The System Management Mode
1097 is used to set the BIOS and power saving options on Toshiba portables.
1099 For information on utilities to make use of this driver see the
1100 Toshiba Linux utilities web site at:
1101 <http://www.buzzard.org.uk/toshiba/>.
1103 Say Y if you intend to run this kernel on a Toshiba portable.
1107 tristate "Dell i8k legacy laptop support"
1109 select SENSORS_DELL_SMM
1111 This option enables legacy /proc/i8k userspace interface in hwmon
1112 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1113 temperature and allows controlling fan speeds of Dell laptops via
1114 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1115 it reports also power and hotkey status. For fan speed control is
1116 needed userspace package i8kutils.
1118 Say Y if you intend to run this kernel on old Dell laptops or want to
1119 use userspace package i8kutils.
1122 config X86_REBOOTFIXUPS
1123 bool "Enable X86 board specific fixups for reboot"
1126 This enables chipset and/or board specific fixups to be done
1127 in order to get reboot to work correctly. This is only needed on
1128 some combinations of hardware and BIOS. The symptom, for which
1129 this config is intended, is when reboot ends with a stalled/hung
1132 Currently, the only fixup is for the Geode machines using
1133 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1135 Say Y if you want to enable the fixup. Currently, it's safe to
1136 enable this option even if you don't need it.
1140 bool "CPU microcode loading support"
1142 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1145 If you say Y here, you will be able to update the microcode on
1146 Intel and AMD processors. The Intel support is for the IA32 family,
1147 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1148 AMD support is for families 0x10 and later. You will obviously need
1149 the actual microcode binary data itself which is not shipped with
1152 The preferred method to load microcode from a detached initrd is described
1153 in Documentation/x86/early-microcode.txt. For that you need to enable
1154 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1155 initrd for microcode blobs.
1157 In addition, you can build-in the microcode into the kernel. For that you
1158 need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
1159 to the CONFIG_EXTRA_FIRMWARE config option.
1161 config MICROCODE_INTEL
1162 bool "Intel microcode loading support"
1163 depends on MICROCODE
1167 This options enables microcode patch loading support for Intel
1170 For the current Intel microcode data package go to
1171 <https://downloadcenter.intel.com> and search for
1172 'Linux Processor Microcode Data File'.
1174 config MICROCODE_AMD
1175 bool "AMD microcode loading support"
1176 depends on MICROCODE
1179 If you select this option, microcode patch loading support for AMD
1180 processors will be enabled.
1182 config MICROCODE_OLD_INTERFACE
1184 depends on MICROCODE
1187 tristate "/dev/cpu/*/msr - Model-specific register support"
1189 This device gives privileged processes access to the x86
1190 Model-Specific Registers (MSRs). It is a character device with
1191 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1192 MSR accesses are directed to a specific CPU on multi-processor
1196 tristate "/dev/cpu/*/cpuid - CPU information support"
1198 This device gives processes access to the x86 CPUID instruction to
1199 be executed on a specific processor. It is a character device
1200 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1204 prompt "High Memory Support"
1211 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1212 However, the address space of 32-bit x86 processors is only 4
1213 Gigabytes large. That means that, if you have a large amount of
1214 physical memory, not all of it can be "permanently mapped" by the
1215 kernel. The physical memory that's not permanently mapped is called
1218 If you are compiling a kernel which will never run on a machine with
1219 more than 1 Gigabyte total physical RAM, answer "off" here (default
1220 choice and suitable for most users). This will result in a "3GB/1GB"
1221 split: 3GB are mapped so that each process sees a 3GB virtual memory
1222 space and the remaining part of the 4GB virtual memory space is used
1223 by the kernel to permanently map as much physical memory as
1226 If the machine has between 1 and 4 Gigabytes physical RAM, then
1229 If more than 4 Gigabytes is used then answer "64GB" here. This
1230 selection turns Intel PAE (Physical Address Extension) mode on.
1231 PAE implements 3-level paging on IA32 processors. PAE is fully
1232 supported by Linux, PAE mode is implemented on all recent Intel
1233 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1234 then the kernel will not boot on CPUs that don't support PAE!
1236 The actual amount of total physical memory will either be
1237 auto detected or can be forced by using a kernel command line option
1238 such as "mem=256M". (Try "man bootparam" or see the documentation of
1239 your boot loader (lilo or loadlin) about how to pass options to the
1240 kernel at boot time.)
1242 If unsure, say "off".
1247 Select this if you have a 32-bit processor and between 1 and 4
1248 gigabytes of physical RAM.
1255 Select this if you have a 32-bit processor and more than 4
1256 gigabytes of physical RAM.
1261 prompt "Memory split" if EXPERT
1265 Select the desired split between kernel and user memory.
1267 If the address range available to the kernel is less than the
1268 physical memory installed, the remaining memory will be available
1269 as "high memory". Accessing high memory is a little more costly
1270 than low memory, as it needs to be mapped into the kernel first.
1271 Note that increasing the kernel address space limits the range
1272 available to user programs, making the address space there
1273 tighter. Selecting anything other than the default 3G/1G split
1274 will also likely make your kernel incompatible with binary-only
1277 If you are not absolutely sure what you are doing, leave this
1281 bool "3G/1G user/kernel split"
1282 config VMSPLIT_3G_OPT
1284 bool "3G/1G user/kernel split (for full 1G low memory)"
1286 bool "2G/2G user/kernel split"
1287 config VMSPLIT_2G_OPT
1289 bool "2G/2G user/kernel split (for full 2G low memory)"
1291 bool "1G/3G user/kernel split"
1296 default 0xB0000000 if VMSPLIT_3G_OPT
1297 default 0x80000000 if VMSPLIT_2G
1298 default 0x78000000 if VMSPLIT_2G_OPT
1299 default 0x40000000 if VMSPLIT_1G
1305 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1308 bool "PAE (Physical Address Extension) Support"
1309 depends on X86_32 && !HIGHMEM4G
1312 PAE is required for NX support, and furthermore enables
1313 larger swapspace support for non-overcommit purposes. It
1314 has the cost of more pagetable lookup overhead, and also
1315 consumes more pagetable space per process.
1317 config ARCH_PHYS_ADDR_T_64BIT
1319 depends on X86_64 || X86_PAE
1321 config ARCH_DMA_ADDR_T_64BIT
1323 depends on X86_64 || HIGHMEM64G
1325 config X86_DIRECT_GBPAGES
1327 depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1329 Certain kernel features effectively disable kernel
1330 linear 1 GB mappings (even if the CPU otherwise
1331 supports them), so don't confuse the user by printing
1332 that we have them enabled.
1334 # Common NUMA Features
1336 bool "Numa Memory Allocation and Scheduler Support"
1338 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1339 default y if X86_BIGSMP
1341 Enable NUMA (Non Uniform Memory Access) support.
1343 The kernel will try to allocate memory used by a CPU on the
1344 local memory controller of the CPU and add some more
1345 NUMA awareness to the kernel.
1347 For 64-bit this is recommended if the system is Intel Core i7
1348 (or later), AMD Opteron, or EM64T NUMA.
1350 For 32-bit this is only needed if you boot a 32-bit
1351 kernel on a 64-bit NUMA platform.
1353 Otherwise, you should say N.
1357 prompt "Old style AMD Opteron NUMA detection"
1358 depends on X86_64 && NUMA && PCI
1360 Enable AMD NUMA node topology detection. You should say Y here if
1361 you have a multi processor AMD system. This uses an old method to
1362 read the NUMA configuration directly from the builtin Northbridge
1363 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1364 which also takes priority if both are compiled in.
1366 config X86_64_ACPI_NUMA
1368 prompt "ACPI NUMA detection"
1369 depends on X86_64 && NUMA && ACPI && PCI
1372 Enable ACPI SRAT based node topology detection.
1374 # Some NUMA nodes have memory ranges that span
1375 # other nodes. Even though a pfn is valid and
1376 # between a node's start and end pfns, it may not
1377 # reside on that node. See memmap_init_zone()
1379 config NODES_SPAN_OTHER_NODES
1381 depends on X86_64_ACPI_NUMA
1384 bool "NUMA emulation"
1387 Enable NUMA emulation. A flat machine will be split
1388 into virtual nodes when booted with "numa=fake=N", where N is the
1389 number of nodes. This is only useful for debugging.
1392 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1394 default "10" if MAXSMP
1395 default "6" if X86_64
1397 depends on NEED_MULTIPLE_NODES
1399 Specify the maximum number of NUMA Nodes available on the target
1400 system. Increases memory reserved to accommodate various tables.
1402 config ARCH_HAVE_MEMORY_PRESENT
1404 depends on X86_32 && DISCONTIGMEM
1406 config NEED_NODE_MEMMAP_SIZE
1408 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1410 config ARCH_FLATMEM_ENABLE
1412 depends on X86_32 && !NUMA
1414 config ARCH_DISCONTIGMEM_ENABLE
1416 depends on NUMA && X86_32
1418 config ARCH_DISCONTIGMEM_DEFAULT
1420 depends on NUMA && X86_32
1422 config ARCH_SPARSEMEM_ENABLE
1424 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1425 select SPARSEMEM_STATIC if X86_32
1426 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1428 config ARCH_SPARSEMEM_DEFAULT
1432 config ARCH_SELECT_MEMORY_MODEL
1434 depends on ARCH_SPARSEMEM_ENABLE
1436 config ARCH_MEMORY_PROBE
1437 bool "Enable sysfs memory/probe interface"
1438 depends on X86_64 && MEMORY_HOTPLUG
1440 This option enables a sysfs memory/probe interface for testing.
1441 See Documentation/memory-hotplug.txt for more information.
1442 If you are unsure how to answer this question, answer N.
1444 config ARCH_PROC_KCORE_TEXT
1446 depends on X86_64 && PROC_KCORE
1448 config ILLEGAL_POINTER_VALUE
1451 default 0xdead000000000000 if X86_64
1455 config X86_PMEM_LEGACY_DEVICE
1458 config X86_PMEM_LEGACY
1459 tristate "Support non-standard NVDIMMs and ADR protected memory"
1460 depends on PHYS_ADDR_T_64BIT
1462 select X86_PMEM_LEGACY_DEVICE
1465 Treat memory marked using the non-standard e820 type of 12 as used
1466 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1467 The kernel will offer these regions to the 'pmem' driver so
1468 they can be used for persistent storage.
1473 bool "Allocate 3rd-level pagetables from highmem"
1476 The VM uses one page table entry for each page of physical memory.
1477 For systems with a lot of RAM, this can be wasteful of precious
1478 low memory. Setting this option will put user-space page table
1479 entries in high memory.
1481 config X86_CHECK_BIOS_CORRUPTION
1482 bool "Check for low memory corruption"
1484 Periodically check for memory corruption in low memory, which
1485 is suspected to be caused by BIOS. Even when enabled in the
1486 configuration, it is disabled at runtime. Enable it by
1487 setting "memory_corruption_check=1" on the kernel command
1488 line. By default it scans the low 64k of memory every 60
1489 seconds; see the memory_corruption_check_size and
1490 memory_corruption_check_period parameters in
1491 Documentation/kernel-parameters.txt to adjust this.
1493 When enabled with the default parameters, this option has
1494 almost no overhead, as it reserves a relatively small amount
1495 of memory and scans it infrequently. It both detects corruption
1496 and prevents it from affecting the running system.
1498 It is, however, intended as a diagnostic tool; if repeatable
1499 BIOS-originated corruption always affects the same memory,
1500 you can use memmap= to prevent the kernel from using that
1503 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1504 bool "Set the default setting of memory_corruption_check"
1505 depends on X86_CHECK_BIOS_CORRUPTION
1508 Set whether the default state of memory_corruption_check is
1511 config X86_RESERVE_LOW
1512 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1516 Specify the amount of low memory to reserve for the BIOS.
1518 The first page contains BIOS data structures that the kernel
1519 must not use, so that page must always be reserved.
1521 By default we reserve the first 64K of physical RAM, as a
1522 number of BIOSes are known to corrupt that memory range
1523 during events such as suspend/resume or monitor cable
1524 insertion, so it must not be used by the kernel.
1526 You can set this to 4 if you are absolutely sure that you
1527 trust the BIOS to get all its memory reservations and usages
1528 right. If you know your BIOS have problems beyond the
1529 default 64K area, you can set this to 640 to avoid using the
1530 entire low memory range.
1532 If you have doubts about the BIOS (e.g. suspend/resume does
1533 not work or there's kernel crashes after certain hardware
1534 hotplug events) then you might want to enable
1535 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1536 typical corruption patterns.
1538 Leave this to the default value of 64 if you are unsure.
1540 config MATH_EMULATION
1542 depends on MODIFY_LDT_SYSCALL
1543 prompt "Math emulation" if X86_32
1545 Linux can emulate a math coprocessor (used for floating point
1546 operations) if you don't have one. 486DX and Pentium processors have
1547 a math coprocessor built in, 486SX and 386 do not, unless you added
1548 a 487DX or 387, respectively. (The messages during boot time can
1549 give you some hints here ["man dmesg"].) Everyone needs either a
1550 coprocessor or this emulation.
1552 If you don't have a math coprocessor, you need to say Y here; if you
1553 say Y here even though you have a coprocessor, the coprocessor will
1554 be used nevertheless. (This behavior can be changed with the kernel
1555 command line option "no387", which comes handy if your coprocessor
1556 is broken. Try "man bootparam" or see the documentation of your boot
1557 loader (lilo or loadlin) about how to pass options to the kernel at
1558 boot time.) This means that it is a good idea to say Y here if you
1559 intend to use this kernel on different machines.
1561 More information about the internals of the Linux math coprocessor
1562 emulation can be found in <file:arch/x86/math-emu/README>.
1564 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1565 kernel, it won't hurt.
1569 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1571 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1572 the Memory Type Range Registers (MTRRs) may be used to control
1573 processor access to memory ranges. This is most useful if you have
1574 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1575 allows bus write transfers to be combined into a larger transfer
1576 before bursting over the PCI/AGP bus. This can increase performance
1577 of image write operations 2.5 times or more. Saying Y here creates a
1578 /proc/mtrr file which may be used to manipulate your processor's
1579 MTRRs. Typically the X server should use this.
1581 This code has a reasonably generic interface so that similar
1582 control registers on other processors can be easily supported
1585 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1586 Registers (ARRs) which provide a similar functionality to MTRRs. For
1587 these, the ARRs are used to emulate the MTRRs.
1588 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1589 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1590 write-combining. All of these processors are supported by this code
1591 and it makes sense to say Y here if you have one of them.
1593 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1594 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1595 can lead to all sorts of problems, so it's good to say Y here.
1597 You can safely say Y even if your machine doesn't have MTRRs, you'll
1598 just add about 9 KB to your kernel.
1600 See <file:Documentation/x86/mtrr.txt> for more information.
1602 config MTRR_SANITIZER
1604 prompt "MTRR cleanup support"
1607 Convert MTRR layout from continuous to discrete, so X drivers can
1608 add writeback entries.
1610 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1611 The largest mtrr entry size for a continuous block can be set with
1616 config MTRR_SANITIZER_ENABLE_DEFAULT
1617 int "MTRR cleanup enable value (0-1)"
1620 depends on MTRR_SANITIZER
1622 Enable mtrr cleanup default value
1624 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1625 int "MTRR cleanup spare reg num (0-7)"
1628 depends on MTRR_SANITIZER
1630 mtrr cleanup spare entries default, it can be changed via
1631 mtrr_spare_reg_nr=N on the kernel command line.
1635 prompt "x86 PAT support" if EXPERT
1638 Use PAT attributes to setup page level cache control.
1640 PATs are the modern equivalents of MTRRs and are much more
1641 flexible than MTRRs.
1643 Say N here if you see bootup problems (boot crash, boot hang,
1644 spontaneous reboots) or a non-working video driver.
1648 config ARCH_USES_PG_UNCACHED
1654 prompt "x86 architectural random number generator" if EXPERT
1656 Enable the x86 architectural RDRAND instruction
1657 (Intel Bull Mountain technology) to generate random numbers.
1658 If supported, this is a high bandwidth, cryptographically
1659 secure hardware random number generator.
1663 prompt "Supervisor Mode Access Prevention" if EXPERT
1665 Supervisor Mode Access Prevention (SMAP) is a security
1666 feature in newer Intel processors. There is a small
1667 performance cost if this enabled and turned on; there is
1668 also a small increase in the kernel size if this is enabled.
1672 config X86_INTEL_MPX
1673 prompt "Intel MPX (Memory Protection Extensions)"
1675 depends on CPU_SUP_INTEL
1677 MPX provides hardware features that can be used in
1678 conjunction with compiler-instrumented code to check
1679 memory references. It is designed to detect buffer
1680 overflow or underflow bugs.
1682 This option enables running applications which are
1683 instrumented or otherwise use MPX. It does not use MPX
1684 itself inside the kernel or to protect the kernel
1685 against bad memory references.
1687 Enabling this option will make the kernel larger:
1688 ~8k of kernel text and 36 bytes of data on a 64-bit
1689 defconfig. It adds a long to the 'mm_struct' which
1690 will increase the kernel memory overhead of each
1691 process and adds some branches to paths used during
1692 exec() and munmap().
1694 For details, see Documentation/x86/intel_mpx.txt
1699 prompt "TSX enable mode"
1700 depends on CPU_SUP_INTEL
1701 default X86_INTEL_TSX_MODE_OFF
1703 Intel's TSX (Transactional Synchronization Extensions) feature
1704 allows to optimize locking protocols through lock elision which
1705 can lead to a noticeable performance boost.
1707 On the other hand it has been shown that TSX can be exploited
1708 to form side channel attacks (e.g. TAA) and chances are there
1709 will be more of those attacks discovered in the future.
1711 Therefore TSX is not enabled by default (aka tsx=off). An admin
1712 might override this decision by tsx=on the command line parameter.
1713 Even with TSX enabled, the kernel will attempt to enable the best
1714 possible TAA mitigation setting depending on the microcode available
1715 for the particular machine.
1717 This option allows to set the default tsx mode between tsx=on, =off
1718 and =auto. See Documentation/kernel-parameters.txt for more
1721 Say off if not sure, auto if TSX is in use but it should be used on safe
1722 platforms or on if TSX is in use and the security aspect of tsx is not
1725 config X86_INTEL_TSX_MODE_OFF
1728 TSX is disabled if possible - equals to tsx=off command line parameter.
1730 config X86_INTEL_TSX_MODE_ON
1733 TSX is always enabled on TSX capable HW - equals the tsx=on command
1736 config X86_INTEL_TSX_MODE_AUTO
1739 TSX is enabled on TSX capable HW that is believed to be safe against
1740 side channel attacks- equals the tsx=auto command line parameter.
1744 bool "EFI runtime service support"
1747 select EFI_RUNTIME_WRAPPERS
1749 This enables the kernel to use EFI runtime services that are
1750 available (such as the EFI variable services).
1752 This option is only useful on systems that have EFI firmware.
1753 In addition, you should use the latest ELILO loader available
1754 at <http://elilo.sourceforge.net> in order to take advantage
1755 of EFI runtime services. However, even with this option, the
1756 resultant kernel should continue to boot on existing non-EFI
1760 bool "EFI stub support"
1761 depends on EFI && !X86_USE_3DNOW
1764 This kernel feature allows a bzImage to be loaded directly
1765 by EFI firmware without the use of a bootloader.
1767 See Documentation/efi-stub.txt for more information.
1770 bool "EFI mixed-mode support"
1771 depends on EFI_STUB && X86_64
1773 Enabling this feature allows a 64-bit kernel to be booted
1774 on a 32-bit firmware, provided that your CPU supports 64-bit
1777 Note that it is not possible to boot a mixed-mode enabled
1778 kernel via the EFI boot stub - a bootloader that supports
1779 the EFI handover protocol must be used.
1785 prompt "Enable seccomp to safely compute untrusted bytecode"
1787 This kernel feature is useful for number crunching applications
1788 that may need to compute untrusted bytecode during their
1789 execution. By using pipes or other transports made available to
1790 the process as file descriptors supporting the read/write
1791 syscalls, it's possible to isolate those applications in
1792 their own address space using seccomp. Once seccomp is
1793 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1794 and the task is only allowed to execute a few safe syscalls
1795 defined by each seccomp mode.
1797 If unsure, say Y. Only embedded should say N here.
1799 source kernel/Kconfig.hz
1802 bool "kexec system call"
1805 kexec is a system call that implements the ability to shutdown your
1806 current kernel, and to start another kernel. It is like a reboot
1807 but it is independent of the system firmware. And like a reboot
1808 you can start any kernel with it, not just Linux.
1810 The name comes from the similarity to the exec system call.
1812 It is an ongoing process to be certain the hardware in a machine
1813 is properly shutdown, so do not be surprised if this code does not
1814 initially work for you. As of this writing the exact hardware
1815 interface is strongly in flux, so no good recommendation can be
1819 bool "kexec file based system call"
1824 depends on CRYPTO_SHA256=y
1826 This is new version of kexec system call. This system call is
1827 file based and takes file descriptors as system call argument
1828 for kernel and initramfs as opposed to list of segments as
1829 accepted by previous system call.
1831 config KEXEC_VERIFY_SIG
1832 bool "Verify kernel signature during kexec_file_load() syscall"
1833 depends on KEXEC_FILE
1835 This option makes kernel signature verification mandatory for
1836 the kexec_file_load() syscall.
1838 In addition to that option, you need to enable signature
1839 verification for the corresponding kernel image type being
1840 loaded in order for this to work.
1842 config KEXEC_BZIMAGE_VERIFY_SIG
1843 bool "Enable bzImage signature verification support"
1844 depends on KEXEC_VERIFY_SIG
1845 depends on SIGNED_PE_FILE_VERIFICATION
1846 select SYSTEM_TRUSTED_KEYRING
1848 Enable bzImage signature verification support.
1851 bool "kernel crash dumps"
1852 depends on X86_64 || (X86_32 && HIGHMEM)
1854 Generate crash dump after being started by kexec.
1855 This should be normally only set in special crash dump kernels
1856 which are loaded in the main kernel with kexec-tools into
1857 a specially reserved region and then later executed after
1858 a crash by kdump/kexec. The crash dump kernel must be compiled
1859 to a memory address not used by the main kernel or BIOS using
1860 PHYSICAL_START, or it must be built as a relocatable image
1861 (CONFIG_RELOCATABLE=y).
1862 For more details see Documentation/kdump/kdump.txt
1866 depends on KEXEC && HIBERNATION
1868 Jump between original kernel and kexeced kernel and invoke
1869 code in physical address mode via KEXEC
1871 config PHYSICAL_START
1872 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1875 This gives the physical address where the kernel is loaded.
1877 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1878 bzImage will decompress itself to above physical address and
1879 run from there. Otherwise, bzImage will run from the address where
1880 it has been loaded by the boot loader and will ignore above physical
1883 In normal kdump cases one does not have to set/change this option
1884 as now bzImage can be compiled as a completely relocatable image
1885 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1886 address. This option is mainly useful for the folks who don't want
1887 to use a bzImage for capturing the crash dump and want to use a
1888 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1889 to be specifically compiled to run from a specific memory area
1890 (normally a reserved region) and this option comes handy.
1892 So if you are using bzImage for capturing the crash dump,
1893 leave the value here unchanged to 0x1000000 and set
1894 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1895 for capturing the crash dump change this value to start of
1896 the reserved region. In other words, it can be set based on
1897 the "X" value as specified in the "crashkernel=YM@XM"
1898 command line boot parameter passed to the panic-ed
1899 kernel. Please take a look at Documentation/kdump/kdump.txt
1900 for more details about crash dumps.
1902 Usage of bzImage for capturing the crash dump is recommended as
1903 one does not have to build two kernels. Same kernel can be used
1904 as production kernel and capture kernel. Above option should have
1905 gone away after relocatable bzImage support is introduced. But it
1906 is present because there are users out there who continue to use
1907 vmlinux for dump capture. This option should go away down the
1910 Don't change this unless you know what you are doing.
1913 bool "Build a relocatable kernel"
1916 This builds a kernel image that retains relocation information
1917 so it can be loaded someplace besides the default 1MB.
1918 The relocations tend to make the kernel binary about 10% larger,
1919 but are discarded at runtime.
1921 One use is for the kexec on panic case where the recovery kernel
1922 must live at a different physical address than the primary
1925 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1926 it has been loaded at and the compile time physical address
1927 (CONFIG_PHYSICAL_START) is used as the minimum location.
1929 config RANDOMIZE_BASE
1930 bool "Randomize the address of the kernel image"
1931 depends on RELOCATABLE
1934 Randomizes the physical and virtual address at which the
1935 kernel image is decompressed, as a security feature that
1936 deters exploit attempts relying on knowledge of the location
1937 of kernel internals.
1939 Entropy is generated using the RDRAND instruction if it is
1940 supported. If RDTSC is supported, it is used as well. If
1941 neither RDRAND nor RDTSC are supported, then randomness is
1942 read from the i8254 timer.
1944 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1945 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1946 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1947 minimum of 2MiB, only 10 bits of entropy is theoretically
1948 possible. At best, due to page table layouts, 64-bit can use
1949 9 bits of entropy and 32-bit uses 8 bits.
1953 config RANDOMIZE_BASE_MAX_OFFSET
1954 hex "Maximum kASLR offset allowed" if EXPERT
1955 depends on RANDOMIZE_BASE
1956 range 0x0 0x20000000 if X86_32
1957 default "0x20000000" if X86_32
1958 range 0x0 0x40000000 if X86_64
1959 default "0x40000000" if X86_64
1961 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1962 memory is used to determine the maximal offset in bytes that will
1963 be applied to the kernel when kernel Address Space Layout
1964 Randomization (kASLR) is active. This must be a multiple of
1967 On 32-bit this is limited to 512MiB by page table layouts. The
1970 On 64-bit this is limited by how the kernel fixmap page table is
1971 positioned, so this cannot be larger than 1GiB currently. Without
1972 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1973 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1974 modules area will shrink to compensate, up to the current maximum
1975 1GiB to 1GiB split. The default is 1GiB.
1977 If unsure, leave at the default value.
1979 # Relocation on x86 needs some additional build support
1980 config X86_NEED_RELOCS
1982 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1984 config PHYSICAL_ALIGN
1985 hex "Alignment value to which kernel should be aligned"
1987 range 0x2000 0x1000000 if X86_32
1988 range 0x200000 0x1000000 if X86_64
1990 This value puts the alignment restrictions on physical address
1991 where kernel is loaded and run from. Kernel is compiled for an
1992 address which meets above alignment restriction.
1994 If bootloader loads the kernel at a non-aligned address and
1995 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1996 address aligned to above value and run from there.
1998 If bootloader loads the kernel at a non-aligned address and
1999 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2000 load address and decompress itself to the address it has been
2001 compiled for and run from there. The address for which kernel is
2002 compiled already meets above alignment restrictions. Hence the
2003 end result is that kernel runs from a physical address meeting
2004 above alignment restrictions.
2006 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2007 this value must be a multiple of 0x200000.
2009 Don't change this unless you know what you are doing.
2015 config BOOTPARAM_HOTPLUG_CPU0
2016 bool "Set default setting of cpu0_hotpluggable"
2018 depends on HOTPLUG_CPU
2020 Set whether default state of cpu0_hotpluggable is on or off.
2022 Say Y here to enable CPU0 hotplug by default. If this switch
2023 is turned on, there is no need to give cpu0_hotplug kernel
2024 parameter and the CPU0 hotplug feature is enabled by default.
2026 Please note: there are two known CPU0 dependencies if you want
2027 to enable the CPU0 hotplug feature either by this switch or by
2028 cpu0_hotplug kernel parameter.
2030 First, resume from hibernate or suspend always starts from CPU0.
2031 So hibernate and suspend are prevented if CPU0 is offline.
2033 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2034 offline if any interrupt can not migrate out of CPU0. There may
2035 be other CPU0 dependencies.
2037 Please make sure the dependencies are under your control before
2038 you enable this feature.
2040 Say N if you don't want to enable CPU0 hotplug feature by default.
2041 You still can enable the CPU0 hotplug feature at boot by kernel
2042 parameter cpu0_hotplug.
2044 config DEBUG_HOTPLUG_CPU0
2046 prompt "Debug CPU0 hotplug"
2047 depends on HOTPLUG_CPU
2049 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2050 soon as possible and boots up userspace with CPU0 offlined. User
2051 can online CPU0 back after boot time.
2053 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2054 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2055 compilation or giving cpu0_hotplug kernel parameter at boot.
2061 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2062 depends on X86_32 || IA32_EMULATION
2064 Certain buggy versions of glibc will crash if they are
2065 presented with a 32-bit vDSO that is not mapped at the address
2066 indicated in its segment table.
2068 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2069 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2070 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2071 the only released version with the bug, but OpenSUSE 9
2072 contains a buggy "glibc 2.3.2".
2074 The symptom of the bug is that everything crashes on startup, saying:
2075 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2077 Saying Y here changes the default value of the vdso32 boot
2078 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2079 This works around the glibc bug but hurts performance.
2081 If unsure, say N: if you are compiling your own kernel, you
2082 are unlikely to be using a buggy version of glibc.
2085 prompt "vsyscall table for legacy applications"
2087 default LEGACY_VSYSCALL_EMULATE
2089 Legacy user code that does not know how to find the vDSO expects
2090 to be able to issue three syscalls by calling fixed addresses in
2091 kernel space. Since this location is not randomized with ASLR,
2092 it can be used to assist security vulnerability exploitation.
2094 This setting can be changed at boot time via the kernel command
2095 line parameter vsyscall=[native|emulate|none].
2097 On a system with recent enough glibc (2.14 or newer) and no
2098 static binaries, you can say None without a performance penalty
2099 to improve security.
2101 If unsure, select "Emulate".
2103 config LEGACY_VSYSCALL_NATIVE
2106 Actual executable code is located in the fixed vsyscall
2107 address mapping, implementing time() efficiently. Since
2108 this makes the mapping executable, it can be used during
2109 security vulnerability exploitation (traditionally as
2110 ROP gadgets). This configuration is not recommended.
2112 config LEGACY_VSYSCALL_EMULATE
2115 The kernel traps and emulates calls into the fixed
2116 vsyscall address mapping. This makes the mapping
2117 non-executable, but it still contains known contents,
2118 which could be used in certain rare security vulnerability
2119 exploits. This configuration is recommended when userspace
2120 still uses the vsyscall area.
2122 config LEGACY_VSYSCALL_NONE
2125 There will be no vsyscall mapping at all. This will
2126 eliminate any risk of ASLR bypass due to the vsyscall
2127 fixed address mapping. Attempts to use the vsyscalls
2128 will be reported to dmesg, so that either old or
2129 malicious userspace programs can be identified.
2134 bool "Built-in kernel command line"
2136 Allow for specifying boot arguments to the kernel at
2137 build time. On some systems (e.g. embedded ones), it is
2138 necessary or convenient to provide some or all of the
2139 kernel boot arguments with the kernel itself (that is,
2140 to not rely on the boot loader to provide them.)
2142 To compile command line arguments into the kernel,
2143 set this option to 'Y', then fill in the
2144 boot arguments in CONFIG_CMDLINE.
2146 Systems with fully functional boot loaders (i.e. non-embedded)
2147 should leave this option set to 'N'.
2150 string "Built-in kernel command string"
2151 depends on CMDLINE_BOOL
2154 Enter arguments here that should be compiled into the kernel
2155 image and used at boot time. If the boot loader provides a
2156 command line at boot time, it is appended to this string to
2157 form the full kernel command line, when the system boots.
2159 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2160 change this behavior.
2162 In most cases, the command line (whether built-in or provided
2163 by the boot loader) should specify the device for the root
2166 config CMDLINE_OVERRIDE
2167 bool "Built-in command line overrides boot loader arguments"
2168 depends on CMDLINE_BOOL
2170 Set this option to 'Y' to have the kernel ignore the boot loader
2171 command line, and use ONLY the built-in command line.
2173 This is used to work around broken boot loaders. This should
2174 be set to 'N' under normal conditions.
2176 config MODIFY_LDT_SYSCALL
2177 bool "Enable the LDT (local descriptor table)" if EXPERT
2180 Linux can allow user programs to install a per-process x86
2181 Local Descriptor Table (LDT) using the modify_ldt(2) system
2182 call. This is required to run 16-bit or segmented code such as
2183 DOSEMU or some Wine programs. It is also used by some very old
2184 threading libraries.
2186 Enabling this feature adds a small amount of overhead to
2187 context switches and increases the low-level kernel attack
2188 surface. Disabling it removes the modify_ldt(2) system call.
2190 Saying 'N' here may make sense for embedded or server kernels.
2192 source "kernel/livepatch/Kconfig"
2196 config ARCH_ENABLE_MEMORY_HOTPLUG
2198 depends on X86_64 || (X86_32 && HIGHMEM)
2200 config ARCH_ENABLE_MEMORY_HOTREMOVE
2202 depends on MEMORY_HOTPLUG
2204 config USE_PERCPU_NUMA_NODE_ID
2208 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2210 depends on X86_64 || X86_PAE
2212 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2214 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2216 menu "Power management and ACPI options"
2218 config ARCH_HIBERNATION_HEADER
2220 depends on X86_64 && HIBERNATION
2222 source "kernel/power/Kconfig"
2224 source "drivers/acpi/Kconfig"
2226 source "drivers/sfi/Kconfig"
2233 tristate "APM (Advanced Power Management) BIOS support"
2234 depends on X86_32 && PM_SLEEP
2236 APM is a BIOS specification for saving power using several different
2237 techniques. This is mostly useful for battery powered laptops with
2238 APM compliant BIOSes. If you say Y here, the system time will be
2239 reset after a RESUME operation, the /proc/apm device will provide
2240 battery status information, and user-space programs will receive
2241 notification of APM "events" (e.g. battery status change).
2243 If you select "Y" here, you can disable actual use of the APM
2244 BIOS by passing the "apm=off" option to the kernel at boot time.
2246 Note that the APM support is almost completely disabled for
2247 machines with more than one CPU.
2249 In order to use APM, you will need supporting software. For location
2250 and more information, read <file:Documentation/power/apm-acpi.txt>
2251 and the Battery Powered Linux mini-HOWTO, available from
2252 <http://www.tldp.org/docs.html#howto>.
2254 This driver does not spin down disk drives (see the hdparm(8)
2255 manpage ("man 8 hdparm") for that), and it doesn't turn off
2256 VESA-compliant "green" monitors.
2258 This driver does not support the TI 4000M TravelMate and the ACER
2259 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2260 desktop machines also don't have compliant BIOSes, and this driver
2261 may cause those machines to panic during the boot phase.
2263 Generally, if you don't have a battery in your machine, there isn't
2264 much point in using this driver and you should say N. If you get
2265 random kernel OOPSes or reboots that don't seem to be related to
2266 anything, try disabling/enabling this option (or disabling/enabling
2269 Some other things you should try when experiencing seemingly random,
2272 1) make sure that you have enough swap space and that it is
2274 2) pass the "no-hlt" option to the kernel
2275 3) switch on floating point emulation in the kernel and pass
2276 the "no387" option to the kernel
2277 4) pass the "floppy=nodma" option to the kernel
2278 5) pass the "mem=4M" option to the kernel (thereby disabling
2279 all but the first 4 MB of RAM)
2280 6) make sure that the CPU is not over clocked.
2281 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2282 8) disable the cache from your BIOS settings
2283 9) install a fan for the video card or exchange video RAM
2284 10) install a better fan for the CPU
2285 11) exchange RAM chips
2286 12) exchange the motherboard.
2288 To compile this driver as a module, choose M here: the
2289 module will be called apm.
2293 config APM_IGNORE_USER_SUSPEND
2294 bool "Ignore USER SUSPEND"
2296 This option will ignore USER SUSPEND requests. On machines with a
2297 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2298 series notebooks, it is necessary to say Y because of a BIOS bug.
2300 config APM_DO_ENABLE
2301 bool "Enable PM at boot time"
2303 Enable APM features at boot time. From page 36 of the APM BIOS
2304 specification: "When disabled, the APM BIOS does not automatically
2305 power manage devices, enter the Standby State, enter the Suspend
2306 State, or take power saving steps in response to CPU Idle calls."
2307 This driver will make CPU Idle calls when Linux is idle (unless this
2308 feature is turned off -- see "Do CPU IDLE calls", below). This
2309 should always save battery power, but more complicated APM features
2310 will be dependent on your BIOS implementation. You may need to turn
2311 this option off if your computer hangs at boot time when using APM
2312 support, or if it beeps continuously instead of suspending. Turn
2313 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2314 T400CDT. This is off by default since most machines do fine without
2319 bool "Make CPU Idle calls when idle"
2321 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2322 On some machines, this can activate improved power savings, such as
2323 a slowed CPU clock rate, when the machine is idle. These idle calls
2324 are made after the idle loop has run for some length of time (e.g.,
2325 333 mS). On some machines, this will cause a hang at boot time or
2326 whenever the CPU becomes idle. (On machines with more than one CPU,
2327 this option does nothing.)
2329 config APM_DISPLAY_BLANK
2330 bool "Enable console blanking using APM"
2332 Enable console blanking using the APM. Some laptops can use this to
2333 turn off the LCD backlight when the screen blanker of the Linux
2334 virtual console blanks the screen. Note that this is only used by
2335 the virtual console screen blanker, and won't turn off the backlight
2336 when using the X Window system. This also doesn't have anything to
2337 do with your VESA-compliant power-saving monitor. Further, this
2338 option doesn't work for all laptops -- it might not turn off your
2339 backlight at all, or it might print a lot of errors to the console,
2340 especially if you are using gpm.
2342 config APM_ALLOW_INTS
2343 bool "Allow interrupts during APM BIOS calls"
2345 Normally we disable external interrupts while we are making calls to
2346 the APM BIOS as a measure to lessen the effects of a badly behaving
2347 BIOS implementation. The BIOS should reenable interrupts if it
2348 needs to. Unfortunately, some BIOSes do not -- especially those in
2349 many of the newer IBM Thinkpads. If you experience hangs when you
2350 suspend, try setting this to Y. Otherwise, say N.
2354 source "drivers/cpufreq/Kconfig"
2356 source "drivers/cpuidle/Kconfig"
2358 source "drivers/idle/Kconfig"
2363 menu "Bus options (PCI etc.)"
2369 Find out whether you have a PCI motherboard. PCI is the name of a
2370 bus system, i.e. the way the CPU talks to the other stuff inside
2371 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2372 VESA. If you have PCI, say Y, otherwise N.
2375 prompt "PCI access mode"
2376 depends on X86_32 && PCI
2379 On PCI systems, the BIOS can be used to detect the PCI devices and
2380 determine their configuration. However, some old PCI motherboards
2381 have BIOS bugs and may crash if this is done. Also, some embedded
2382 PCI-based systems don't have any BIOS at all. Linux can also try to
2383 detect the PCI hardware directly without using the BIOS.
2385 With this option, you can specify how Linux should detect the
2386 PCI devices. If you choose "BIOS", the BIOS will be used,
2387 if you choose "Direct", the BIOS won't be used, and if you
2388 choose "MMConfig", then PCI Express MMCONFIG will be used.
2389 If you choose "Any", the kernel will try MMCONFIG, then the
2390 direct access method and falls back to the BIOS if that doesn't
2391 work. If unsure, go with the default, which is "Any".
2396 config PCI_GOMMCONFIG
2413 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2415 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2418 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2422 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2426 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2430 depends on PCI && XEN
2438 bool "Support mmconfig PCI config space access"
2439 depends on X86_64 && PCI && ACPI
2441 config PCI_CNB20LE_QUIRK
2442 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2445 Read the PCI windows out of the CNB20LE host bridge. This allows
2446 PCI hotplug to work on systems with the CNB20LE chipset which do
2449 There's no public spec for this chipset, and this functionality
2450 is known to be incomplete.
2452 You should say N unless you know you need this.
2454 source "drivers/pci/pcie/Kconfig"
2456 source "drivers/pci/Kconfig"
2458 # x86_64 have no ISA slots, but can have ISA-style DMA.
2460 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2463 Enables ISA-style DMA support for devices requiring such controllers.
2471 Find out whether you have ISA slots on your motherboard. ISA is the
2472 name of a bus system, i.e. the way the CPU talks to the other stuff
2473 inside your box. Other bus systems are PCI, EISA, MicroChannel
2474 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2475 newer boards don't support it. If you have ISA, say Y, otherwise N.
2481 The Extended Industry Standard Architecture (EISA) bus was
2482 developed as an open alternative to the IBM MicroChannel bus.
2484 The EISA bus provided some of the features of the IBM MicroChannel
2485 bus while maintaining backward compatibility with cards made for
2486 the older ISA bus. The EISA bus saw limited use between 1988 and
2487 1995 when it was made obsolete by the PCI bus.
2489 Say Y here if you are building a kernel for an EISA-based machine.
2493 source "drivers/eisa/Kconfig"
2496 tristate "NatSemi SCx200 support"
2498 This provides basic support for National Semiconductor's
2499 (now AMD's) Geode processors. The driver probes for the
2500 PCI-IDs of several on-chip devices, so its a good dependency
2501 for other scx200_* drivers.
2503 If compiled as a module, the driver is named scx200.
2505 config SCx200HR_TIMER
2506 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2510 This driver provides a clocksource built upon the on-chip
2511 27MHz high-resolution timer. Its also a workaround for
2512 NSC Geode SC-1100's buggy TSC, which loses time when the
2513 processor goes idle (as is done by the scheduler). The
2514 other workaround is idle=poll boot option.
2517 bool "One Laptop Per Child support"
2524 Add support for detecting the unique features of the OLPC
2528 bool "OLPC XO-1 Power Management"
2529 depends on OLPC && MFD_CS5535=y && PM_SLEEP
2531 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2534 bool "OLPC XO-1 Real Time Clock"
2535 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2537 Add support for the XO-1 real time clock, which can be used as a
2538 programmable wakeup source.
2541 bool "OLPC XO-1 SCI extras"
2542 depends on OLPC && OLPC_XO1_PM
2548 Add support for SCI-based features of the OLPC XO-1 laptop:
2549 - EC-driven system wakeups
2553 - AC adapter status updates
2554 - Battery status updates
2556 config OLPC_XO15_SCI
2557 bool "OLPC XO-1.5 SCI extras"
2558 depends on OLPC && ACPI
2561 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2562 - EC-driven system wakeups
2563 - AC adapter status updates
2564 - Battery status updates
2567 bool "PCEngines ALIX System Support (LED setup)"
2570 This option enables system support for the PCEngines ALIX.
2571 At present this just sets up LEDs for GPIO control on
2572 ALIX2/3/6 boards. However, other system specific setup should
2575 Note: You must still enable the drivers for GPIO and LED support
2576 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2578 Note: You have to set alix.force=1 for boards with Award BIOS.
2581 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2584 This option enables system support for the Soekris Engineering net5501.
2587 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2591 This option enables system support for the Traverse Technologies GEOS.
2594 bool "Technologic Systems TS-5500 platform support"
2596 select CHECK_SIGNATURE
2600 This option enables system support for the Technologic Systems TS-5500.
2606 depends on CPU_SUP_AMD && PCI
2608 source "drivers/pcmcia/Kconfig"
2610 source "drivers/pci/hotplug/Kconfig"
2613 tristate "RapidIO support"
2617 If enabled this option will include drivers and the core
2618 infrastructure code to support RapidIO interconnect devices.
2620 source "drivers/rapidio/Kconfig"
2623 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2625 Firmwares often provide initial graphics framebuffers so the BIOS,
2626 bootloader or kernel can show basic video-output during boot for
2627 user-guidance and debugging. Historically, x86 used the VESA BIOS
2628 Extensions and EFI-framebuffers for this, which are mostly limited
2630 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2631 framebuffers so the new generic system-framebuffer drivers can be
2632 used on x86. If the framebuffer is not compatible with the generic
2633 modes, it is adverticed as fallback platform framebuffer so legacy
2634 drivers like efifb, vesafb and uvesafb can pick it up.
2635 If this option is not selected, all system framebuffers are always
2636 marked as fallback platform framebuffers as usual.
2638 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2639 not be able to pick up generic system framebuffers if this option
2640 is selected. You are highly encouraged to enable simplefb as
2641 replacement if you select this option. simplefb can correctly deal
2642 with generic system framebuffers. But you should still keep vesafb
2643 and others enabled as fallback if a system framebuffer is
2644 incompatible with simplefb.
2651 menu "Executable file formats / Emulations"
2653 source "fs/Kconfig.binfmt"
2655 config IA32_EMULATION
2656 bool "IA32 Emulation"
2659 select COMPAT_BINFMT_ELF
2660 select ARCH_WANT_OLD_COMPAT_IPC
2662 Include code to run legacy 32-bit programs under a
2663 64-bit kernel. You should likely turn this on, unless you're
2664 100% sure that you don't have any 32-bit programs left.
2667 tristate "IA32 a.out support"
2668 depends on IA32_EMULATION
2670 Support old a.out binaries in the 32bit emulation.
2673 bool "x32 ABI for 64-bit mode"
2676 Include code to run binaries for the x32 native 32-bit ABI
2677 for 64-bit processors. An x32 process gets access to the
2678 full 64-bit register file and wide data path while leaving
2679 pointers at 32 bits for smaller memory footprint.
2681 You will need a recent binutils (2.22 or later) with
2682 elf32_x86_64 support enabled to compile a kernel with this
2687 depends on IA32_EMULATION || X86_X32
2690 config COMPAT_FOR_U64_ALIGNMENT
2693 config SYSVIPC_COMPAT
2701 config HAVE_ATOMIC_IOMAP
2705 config X86_DEV_DMA_OPS
2707 depends on X86_64 || STA2X11
2709 config X86_DMA_REMAP
2717 source "net/Kconfig"
2719 source "drivers/Kconfig"
2721 source "drivers/firmware/Kconfig"
2725 source "arch/x86/Kconfig.debug"
2727 source "security/Kconfig"
2729 source "crypto/Kconfig"
2731 source "arch/x86/kvm/Kconfig"
2733 source "lib/Kconfig"