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_DEBUG_STRICT_USER_COPY_CHECKS
28 select ARCH_HAS_DEVMEM_IS_ALLOWED
29 select ARCH_HAS_ELF_RANDOMIZE
30 select ARCH_HAS_FAST_MULTIPLIER
31 select ARCH_HAS_GCOV_PROFILE_ALL
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_HUGE_VMAP if X86_64 || X86_PAE
84 select HAVE_ARCH_JUMP_LABEL
85 select HAVE_ARCH_KASAN if X86_64 && SPARSEMEM_VMEMMAP
87 select HAVE_ARCH_KMEMCHECK
88 select HAVE_ARCH_MMAP_RND_BITS if MMU
89 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
90 select HAVE_ARCH_SECCOMP_FILTER
91 select HAVE_ARCH_SOFT_DIRTY if X86_64
92 select HAVE_ARCH_TRACEHOOK
93 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
94 select HAVE_EBPF_JIT if X86_64
95 select HAVE_CC_STACKPROTECTOR
96 select HAVE_CMPXCHG_DOUBLE
97 select HAVE_CMPXCHG_LOCAL
98 select HAVE_CONTEXT_TRACKING if X86_64
99 select HAVE_COPY_THREAD_TLS
100 select HAVE_C_RECORDMCOUNT
101 select HAVE_DEBUG_KMEMLEAK
102 select HAVE_DEBUG_STACKOVERFLOW
103 select HAVE_DMA_API_DEBUG
104 select HAVE_DMA_CONTIGUOUS
105 select HAVE_DYNAMIC_FTRACE
106 select HAVE_DYNAMIC_FTRACE_WITH_REGS
107 select HAVE_EFFICIENT_UNALIGNED_ACCESS
108 select HAVE_EXIT_THREAD
109 select HAVE_FENTRY if X86_64
110 select HAVE_FTRACE_MCOUNT_RECORD
111 select HAVE_FUNCTION_GRAPH_FP_TEST
112 select HAVE_FUNCTION_GRAPH_TRACER
113 select HAVE_FUNCTION_TRACER
114 select HAVE_GCC_PLUGINS
115 select HAVE_GENERIC_DMA_COHERENT if X86_32
116 select HAVE_HW_BREAKPOINT
118 select HAVE_IOREMAP_PROT
119 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
120 select HAVE_IRQ_TIME_ACCOUNTING
121 select HAVE_KERNEL_BZIP2
122 select HAVE_KERNEL_GZIP
123 select HAVE_KERNEL_LZ4
124 select HAVE_KERNEL_LZMA
125 select HAVE_KERNEL_LZO
126 select HAVE_KERNEL_XZ
128 select HAVE_KPROBES_ON_FTRACE
129 select HAVE_KRETPROBES
131 select HAVE_LIVEPATCH if X86_64
133 select HAVE_MEMBLOCK_NODE_MAP
134 select HAVE_MIXED_BREAKPOINTS_REGS
137 select HAVE_OPTPROBES
138 select HAVE_PCSPKR_PLATFORM
139 select HAVE_PERF_EVENTS
140 select HAVE_PERF_EVENTS_NMI
141 select HAVE_PERF_REGS
142 select HAVE_PERF_USER_STACK_DUMP
143 select HAVE_REGS_AND_STACK_ACCESS_API
144 select HAVE_SYSCALL_TRACEPOINTS
145 select HAVE_UID16 if X86_32 || IA32_EMULATION
146 select HAVE_UNSTABLE_SCHED_CLOCK
147 select HAVE_USER_RETURN_NOTIFIER
148 select IRQ_FORCED_THREADING
149 select MODULES_USE_ELF_RELA if X86_64
150 select MODULES_USE_ELF_REL if X86_32
151 select OLD_SIGACTION if X86_32
152 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
157 select SYSCTL_EXCEPTION_TRACE
158 select USER_STACKTRACE_SUPPORT
160 select X86_DEV_DMA_OPS if X86_64
161 select X86_FEATURE_NAMES if PROC_FS
162 select HAVE_STACK_VALIDATION if X86_64
163 select ARCH_USES_HIGH_VMA_FLAGS if X86_INTEL_MEMORY_PROTECTION_KEYS
164 select ARCH_HAS_PKEYS if X86_INTEL_MEMORY_PROTECTION_KEYS
166 config INSTRUCTION_DECODER
168 depends on KPROBES || PERF_EVENTS || UPROBES
172 default "elf32-i386" if X86_32
173 default "elf64-x86-64" if X86_64
175 config ARCH_DEFCONFIG
177 default "arch/x86/configs/i386_defconfig" if X86_32
178 default "arch/x86/configs/x86_64_defconfig" if X86_64
180 config LOCKDEP_SUPPORT
183 config STACKTRACE_SUPPORT
189 config ARCH_MMAP_RND_BITS_MIN
193 config ARCH_MMAP_RND_BITS_MAX
197 config ARCH_MMAP_RND_COMPAT_BITS_MIN
200 config ARCH_MMAP_RND_COMPAT_BITS_MAX
206 config NEED_DMA_MAP_STATE
208 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
210 config NEED_SG_DMA_LENGTH
213 config GENERIC_ISA_DMA
215 depends on ISA_DMA_API
220 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
222 config GENERIC_BUG_RELATIVE_POINTERS
225 config GENERIC_HWEIGHT
228 config ARCH_MAY_HAVE_PC_FDC
230 depends on ISA_DMA_API
232 config RWSEM_XCHGADD_ALGORITHM
235 config GENERIC_CALIBRATE_DELAY
238 config ARCH_HAS_CPU_RELAX
241 config ARCH_HAS_CACHE_LINE_SIZE
244 config HAVE_SETUP_PER_CPU_AREA
247 config NEED_PER_CPU_EMBED_FIRST_CHUNK
250 config NEED_PER_CPU_PAGE_FIRST_CHUNK
253 config ARCH_HIBERNATION_POSSIBLE
256 config ARCH_SUSPEND_POSSIBLE
259 config ARCH_WANT_HUGE_PMD_SHARE
262 config ARCH_WANT_GENERAL_HUGETLB
271 config ARCH_SUPPORTS_OPTIMIZED_INLINING
274 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
277 config KASAN_SHADOW_OFFSET
280 default 0xdffffc0000000000
282 config HAVE_INTEL_TXT
284 depends on INTEL_IOMMU && ACPI
288 depends on X86_32 && SMP
292 depends on X86_64 && SMP
294 config X86_32_LAZY_GS
296 depends on X86_32 && !CC_STACKPROTECTOR
298 config ARCH_SUPPORTS_UPROBES
301 config FIX_EARLYCON_MEM
307 config PGTABLE_LEVELS
313 source "init/Kconfig"
314 source "kernel/Kconfig.freezer"
316 menu "Processor type and features"
319 bool "DMA memory allocation support" if EXPERT
322 DMA memory allocation support allows devices with less than 32-bit
323 addressing to allocate within the first 16MB of address space.
324 Disable if no such devices will be used.
329 bool "Symmetric multi-processing support"
331 This enables support for systems with more than one CPU. If you have
332 a system with only one CPU, say N. If you have a system with more
335 If you say N here, the kernel will run on uni- and multiprocessor
336 machines, but will use only one CPU of a multiprocessor machine. If
337 you say Y here, the kernel will run on many, but not all,
338 uniprocessor machines. On a uniprocessor machine, the kernel
339 will run faster if you say N here.
341 Note that if you say Y here and choose architecture "586" or
342 "Pentium" under "Processor family", the kernel will not work on 486
343 architectures. Similarly, multiprocessor kernels for the "PPro"
344 architecture may not work on all Pentium based boards.
346 People using multiprocessor machines who say Y here should also say
347 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
348 Management" code will be disabled if you say Y here.
350 See also <file:Documentation/x86/i386/IO-APIC.txt>,
351 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
352 <http://www.tldp.org/docs.html#howto>.
354 If you don't know what to do here, say N.
356 config X86_FEATURE_NAMES
357 bool "Processor feature human-readable names" if EMBEDDED
360 This option compiles in a table of x86 feature bits and corresponding
361 names. This is required to support /proc/cpuinfo and a few kernel
362 messages. You can disable this to save space, at the expense of
363 making those few kernel messages show numeric feature bits instead.
367 config X86_FAST_FEATURE_TESTS
368 bool "Fast CPU feature tests" if EMBEDDED
371 Some fast-paths in the kernel depend on the capabilities of the CPU.
372 Say Y here for the kernel to patch in the appropriate code at runtime
373 based on the capabilities of the CPU. The infrastructure for patching
374 code at runtime takes up some additional space; space-constrained
375 embedded systems may wish to say N here to produce smaller, slightly
379 bool "Support x2apic"
380 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
382 This enables x2apic support on CPUs that have this feature.
384 This allows 32-bit apic IDs (so it can support very large systems),
385 and accesses the local apic via MSRs not via mmio.
387 If you don't know what to do here, say N.
390 bool "Enable MPS table" if ACPI || SFI
392 depends on X86_LOCAL_APIC
394 For old smp systems that do not have proper acpi support. Newer systems
395 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
398 bool "Support for big SMP systems with more than 8 CPUs"
399 depends on X86_32 && SMP
401 This option is needed for the systems that have more than 8 CPUs
405 depends on X86_GOLDFISH
408 config X86_EXTENDED_PLATFORM
409 bool "Support for extended (non-PC) x86 platforms"
412 If you disable this option then the kernel will only support
413 standard PC platforms. (which covers the vast majority of
416 If you enable this option then you'll be able to select support
417 for the following (non-PC) 32 bit x86 platforms:
418 Goldfish (Android emulator)
421 SGI 320/540 (Visual Workstation)
422 STA2X11-based (e.g. Northville)
423 Moorestown MID devices
425 If you have one of these systems, or if you want to build a
426 generic distribution kernel, say Y here - otherwise say N.
430 config X86_EXTENDED_PLATFORM
431 bool "Support for extended (non-PC) x86 platforms"
434 If you disable this option then the kernel will only support
435 standard PC platforms. (which covers the vast majority of
438 If you enable this option then you'll be able to select support
439 for the following (non-PC) 64 bit x86 platforms:
444 If you have one of these systems, or if you want to build a
445 generic distribution kernel, say Y here - otherwise say N.
447 # This is an alphabetically sorted list of 64 bit extended platforms
448 # Please maintain the alphabetic order if and when there are additions
450 bool "Numascale NumaChip"
452 depends on X86_EXTENDED_PLATFORM
455 depends on X86_X2APIC
456 depends on PCI_MMCONFIG
458 Adds support for Numascale NumaChip large-SMP systems. Needed to
459 enable more than ~168 cores.
460 If you don't have one of these, you should say N here.
464 select HYPERVISOR_GUEST
466 depends on X86_64 && PCI
467 depends on X86_EXTENDED_PLATFORM
470 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
471 supposed to run on these EM64T-based machines. Only choose this option
472 if you have one of these machines.
475 bool "SGI Ultraviolet"
477 depends on X86_EXTENDED_PLATFORM
480 depends on X86_X2APIC
483 This option is needed in order to support SGI Ultraviolet systems.
484 If you don't have one of these, you should say N here.
486 # Following is an alphabetically sorted list of 32 bit extended platforms
487 # Please maintain the alphabetic order if and when there are additions
490 bool "Goldfish (Virtual Platform)"
491 depends on X86_EXTENDED_PLATFORM
493 Enable support for the Goldfish virtual platform used primarily
494 for Android development. Unless you are building for the Android
495 Goldfish emulator say N here.
498 bool "CE4100 TV platform"
500 depends on PCI_GODIRECT
501 depends on X86_IO_APIC
503 depends on X86_EXTENDED_PLATFORM
504 select X86_REBOOTFIXUPS
506 select OF_EARLY_FLATTREE
508 Select for the Intel CE media processor (CE4100) SOC.
509 This option compiles in support for the CE4100 SOC for settop
510 boxes and media devices.
513 bool "Intel MID platform support"
514 depends on X86_EXTENDED_PLATFORM
515 depends on X86_PLATFORM_DEVICES
517 depends on X86_64 || (PCI_GOANY && X86_32)
518 depends on X86_IO_APIC
524 select MFD_INTEL_MSIC
526 Select to build a kernel capable of supporting Intel MID (Mobile
527 Internet Device) platform systems which do not have the PCI legacy
528 interfaces. If you are building for a PC class system say N here.
530 Intel MID platforms are based on an Intel processor and chipset which
531 consume less power than most of the x86 derivatives.
533 config X86_INTEL_QUARK
534 bool "Intel Quark platform support"
536 depends on X86_EXTENDED_PLATFORM
537 depends on X86_PLATFORM_DEVICES
541 depends on X86_IO_APIC
546 Select to include support for Quark X1000 SoC.
547 Say Y here if you have a Quark based system such as the Arduino
548 compatible Intel Galileo.
550 config X86_INTEL_LPSS
551 bool "Intel Low Power Subsystem Support"
552 depends on X86 && ACPI
557 Select to build support for Intel Low Power Subsystem such as
558 found on Intel Lynxpoint PCH. Selecting this option enables
559 things like clock tree (common clock framework) and pincontrol
560 which are needed by the LPSS peripheral drivers.
562 config X86_AMD_PLATFORM_DEVICE
563 bool "AMD ACPI2Platform devices support"
568 Select to interpret AMD specific ACPI device to platform device
569 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
570 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
571 implemented under PINCTRL subsystem.
574 tristate "Intel SoC IOSF Sideband support for SoC platforms"
577 This option enables sideband register access support for Intel SoC
578 platforms. On these platforms the IOSF sideband is used in lieu of
579 MSR's for some register accesses, mostly but not limited to thermal
580 and power. Drivers may query the availability of this device to
581 determine if they need the sideband in order to work on these
582 platforms. The sideband is available on the following SoC products.
583 This list is not meant to be exclusive.
588 You should say Y if you are running a kernel on one of these SoC's.
590 config IOSF_MBI_DEBUG
591 bool "Enable IOSF sideband access through debugfs"
592 depends on IOSF_MBI && DEBUG_FS
594 Select this option to expose the IOSF sideband access registers (MCR,
595 MDR, MCRX) through debugfs to write and read register information from
596 different units on the SoC. This is most useful for obtaining device
597 state information for debug and analysis. As this is a general access
598 mechanism, users of this option would have specific knowledge of the
599 device they want to access.
601 If you don't require the option or are in doubt, say N.
604 bool "RDC R-321x SoC"
606 depends on X86_EXTENDED_PLATFORM
608 select X86_REBOOTFIXUPS
610 This option is needed for RDC R-321x system-on-chip, also known
612 If you don't have one of these chips, you should say N here.
614 config X86_32_NON_STANDARD
615 bool "Support non-standard 32-bit SMP architectures"
616 depends on X86_32 && SMP
617 depends on X86_EXTENDED_PLATFORM
619 This option compiles in the bigsmp and STA2X11 default
620 subarchitectures. It is intended for a generic binary
621 kernel. If you select them all, kernel will probe it one by
622 one and will fallback to default.
624 # Alphabetically sorted list of Non standard 32 bit platforms
626 config X86_SUPPORTS_MEMORY_FAILURE
628 # MCE code calls memory_failure():
630 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
631 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
632 depends on X86_64 || !SPARSEMEM
633 select ARCH_SUPPORTS_MEMORY_FAILURE
636 bool "STA2X11 Companion Chip Support"
637 depends on X86_32_NON_STANDARD && PCI
638 select X86_DEV_DMA_OPS
645 This adds support for boards based on the STA2X11 IO-Hub,
646 a.k.a. "ConneXt". The chip is used in place of the standard
647 PC chipset, so all "standard" peripherals are missing. If this
648 option is selected the kernel will still be able to boot on
649 standard PC machines.
652 tristate "Eurobraille/Iris poweroff module"
655 The Iris machines from EuroBraille do not have APM or ACPI support
656 to shut themselves down properly. A special I/O sequence is
657 needed to do so, which is what this module does at
660 This is only for Iris machines from EuroBraille.
664 config SCHED_OMIT_FRAME_POINTER
666 prompt "Single-depth WCHAN output"
669 Calculate simpler /proc/<PID>/wchan values. If this option
670 is disabled then wchan values will recurse back to the
671 caller function. This provides more accurate wchan values,
672 at the expense of slightly more scheduling overhead.
674 If in doubt, say "Y".
676 menuconfig HYPERVISOR_GUEST
677 bool "Linux guest support"
679 Say Y here to enable options for running Linux under various hyper-
680 visors. This option enables basic hypervisor detection and platform
683 If you say N, all options in this submenu will be skipped and
684 disabled, and Linux guest support won't be built in.
689 bool "Enable paravirtualization code"
691 This changes the kernel so it can modify itself when it is run
692 under a hypervisor, potentially improving performance significantly
693 over full virtualization. However, when run without a hypervisor
694 the kernel is theoretically slower and slightly larger.
696 config PARAVIRT_DEBUG
697 bool "paravirt-ops debugging"
698 depends on PARAVIRT && DEBUG_KERNEL
700 Enable to debug paravirt_ops internals. Specifically, BUG if
701 a paravirt_op is missing when it is called.
703 config PARAVIRT_SPINLOCKS
704 bool "Paravirtualization layer for spinlocks"
705 depends on PARAVIRT && SMP
706 select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS
708 Paravirtualized spinlocks allow a pvops backend to replace the
709 spinlock implementation with something virtualization-friendly
710 (for example, block the virtual CPU rather than spinning).
712 It has a minimal impact on native kernels and gives a nice performance
713 benefit on paravirtualized KVM / Xen kernels.
715 If you are unsure how to answer this question, answer Y.
717 config QUEUED_LOCK_STAT
718 bool "Paravirt queued spinlock statistics"
719 depends on PARAVIRT_SPINLOCKS && DEBUG_FS && QUEUED_SPINLOCKS
721 Enable the collection of statistical data on the slowpath
722 behavior of paravirtualized queued spinlocks and report
725 source "arch/x86/xen/Kconfig"
728 bool "KVM Guest support (including kvmclock)"
730 select PARAVIRT_CLOCK
733 This option enables various optimizations for running under the KVM
734 hypervisor. It includes a paravirtualized clock, so that instead
735 of relying on a PIT (or probably other) emulation by the
736 underlying device model, the host provides the guest with
737 timing infrastructure such as time of day, and system time
740 bool "Enable debug information for KVM Guests in debugfs"
741 depends on KVM_GUEST && DEBUG_FS
744 This option enables collection of various statistics for KVM guest.
745 Statistics are displayed in debugfs filesystem. Enabling this option
746 may incur significant overhead.
748 source "arch/x86/lguest/Kconfig"
750 config PARAVIRT_TIME_ACCOUNTING
751 bool "Paravirtual steal time accounting"
755 Select this option to enable fine granularity task steal time
756 accounting. Time spent executing other tasks in parallel with
757 the current vCPU is discounted from the vCPU power. To account for
758 that, there can be a small performance impact.
760 If in doubt, say N here.
762 config PARAVIRT_CLOCK
765 endif #HYPERVISOR_GUEST
770 source "arch/x86/Kconfig.cpu"
774 prompt "HPET Timer Support" if X86_32
776 Use the IA-PC HPET (High Precision Event Timer) to manage
777 time in preference to the PIT and RTC, if a HPET is
779 HPET is the next generation timer replacing legacy 8254s.
780 The HPET provides a stable time base on SMP
781 systems, unlike the TSC, but it is more expensive to access,
782 as it is off-chip. The interface used is documented
783 in the HPET spec, revision 1.
785 You can safely choose Y here. However, HPET will only be
786 activated if the platform and the BIOS support this feature.
787 Otherwise the 8254 will be used for timing services.
789 Choose N to continue using the legacy 8254 timer.
791 config HPET_EMULATE_RTC
793 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
796 def_bool y if X86_INTEL_MID
797 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
799 depends on X86_INTEL_MID && SFI
801 APB timer is the replacement for 8254, HPET on X86 MID platforms.
802 The APBT provides a stable time base on SMP
803 systems, unlike the TSC, but it is more expensive to access,
804 as it is off-chip. APB timers are always running regardless of CPU
805 C states, they are used as per CPU clockevent device when possible.
807 # Mark as expert because too many people got it wrong.
808 # The code disables itself when not needed.
811 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
812 bool "Enable DMI scanning" if EXPERT
814 Enabled scanning of DMI to identify machine quirks. Say Y
815 here unless you have verified that your setup is not
816 affected by entries in the DMI blacklist. Required by PNP
820 bool "Old AMD GART IOMMU support"
822 depends on X86_64 && PCI && AMD_NB
824 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
825 GART based hardware IOMMUs.
827 The GART supports full DMA access for devices with 32-bit access
828 limitations, on systems with more than 3 GB. This is usually needed
829 for USB, sound, many IDE/SATA chipsets and some other devices.
831 Newer systems typically have a modern AMD IOMMU, supported via
832 the CONFIG_AMD_IOMMU=y config option.
834 In normal configurations this driver is only active when needed:
835 there's more than 3 GB of memory and the system contains a
836 32-bit limited device.
841 bool "IBM Calgary IOMMU support"
843 depends on X86_64 && PCI
845 Support for hardware IOMMUs in IBM's xSeries x366 and x460
846 systems. Needed to run systems with more than 3GB of memory
847 properly with 32-bit PCI devices that do not support DAC
848 (Double Address Cycle). Calgary also supports bus level
849 isolation, where all DMAs pass through the IOMMU. This
850 prevents them from going anywhere except their intended
851 destination. This catches hard-to-find kernel bugs and
852 mis-behaving drivers and devices that do not use the DMA-API
853 properly to set up their DMA buffers. The IOMMU can be
854 turned off at boot time with the iommu=off parameter.
855 Normally the kernel will make the right choice by itself.
858 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
860 prompt "Should Calgary be enabled by default?"
861 depends on CALGARY_IOMMU
863 Should Calgary be enabled by default? if you choose 'y', Calgary
864 will be used (if it exists). If you choose 'n', Calgary will not be
865 used even if it exists. If you choose 'n' and would like to use
866 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
869 # need this always selected by IOMMU for the VIA workaround
873 Support for software bounce buffers used on x86-64 systems
874 which don't have a hardware IOMMU. Using this PCI devices
875 which can only access 32-bits of memory can be used on systems
876 with more than 3 GB of memory.
881 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
884 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
885 depends on X86_64 && SMP && DEBUG_KERNEL
886 select CPUMASK_OFFSTACK
888 Enable maximum number of CPUS and NUMA Nodes for this architecture.
892 int "Maximum number of CPUs" if SMP && !MAXSMP
893 range 2 8 if SMP && X86_32 && !X86_BIGSMP
894 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
895 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
897 default "8192" if MAXSMP
898 default "32" if SMP && X86_BIGSMP
899 default "8" if SMP && X86_32
902 This allows you to specify the maximum number of CPUs which this
903 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
904 supported value is 8192, otherwise the maximum value is 512. The
905 minimum value which makes sense is 2.
907 This is purely to save memory - each supported CPU adds
908 approximately eight kilobytes to the kernel image.
911 bool "SMT (Hyperthreading) scheduler support"
914 SMT scheduler support improves the CPU scheduler's decision making
915 when dealing with Intel Pentium 4 chips with HyperThreading at a
916 cost of slightly increased overhead in some places. If unsure say
921 prompt "Multi-core scheduler support"
924 Multi-core scheduler support improves the CPU scheduler's decision
925 making when dealing with multi-core CPU chips at a cost of slightly
926 increased overhead in some places. If unsure say N here.
928 source "kernel/Kconfig.preempt"
932 depends on !SMP && X86_LOCAL_APIC
935 bool "Local APIC support on uniprocessors" if !PCI_MSI
937 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
939 A local APIC (Advanced Programmable Interrupt Controller) is an
940 integrated interrupt controller in the CPU. If you have a single-CPU
941 system which has a processor with a local APIC, you can say Y here to
942 enable and use it. If you say Y here even though your machine doesn't
943 have a local APIC, then the kernel will still run with no slowdown at
944 all. The local APIC supports CPU-generated self-interrupts (timer,
945 performance counters), and the NMI watchdog which detects hard
949 bool "IO-APIC support on uniprocessors"
950 depends on X86_UP_APIC
952 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
953 SMP-capable replacement for PC-style interrupt controllers. Most
954 SMP systems and many recent uniprocessor systems have one.
956 If you have a single-CPU system with an IO-APIC, you can say Y here
957 to use it. If you say Y here even though your machine doesn't have
958 an IO-APIC, then the kernel will still run with no slowdown at all.
960 config X86_LOCAL_APIC
962 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
963 select IRQ_DOMAIN_HIERARCHY
964 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
968 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
970 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
971 bool "Reroute for broken boot IRQs"
972 depends on X86_IO_APIC
974 This option enables a workaround that fixes a source of
975 spurious interrupts. This is recommended when threaded
976 interrupt handling is used on systems where the generation of
977 superfluous "boot interrupts" cannot be disabled.
979 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
980 entry in the chipset's IO-APIC is masked (as, e.g. the RT
981 kernel does during interrupt handling). On chipsets where this
982 boot IRQ generation cannot be disabled, this workaround keeps
983 the original IRQ line masked so that only the equivalent "boot
984 IRQ" is delivered to the CPUs. The workaround also tells the
985 kernel to set up the IRQ handler on the boot IRQ line. In this
986 way only one interrupt is delivered to the kernel. Otherwise
987 the spurious second interrupt may cause the kernel to bring
988 down (vital) interrupt lines.
990 Only affects "broken" chipsets. Interrupt sharing may be
991 increased on these systems.
994 bool "Machine Check / overheating reporting"
995 select GENERIC_ALLOCATOR
998 Machine Check support allows the processor to notify the
999 kernel if it detects a problem (e.g. overheating, data corruption).
1000 The action the kernel takes depends on the severity of the problem,
1001 ranging from warning messages to halting the machine.
1003 config X86_MCE_INTEL
1005 prompt "Intel MCE features"
1006 depends on X86_MCE && X86_LOCAL_APIC
1008 Additional support for intel specific MCE features such as
1009 the thermal monitor.
1013 prompt "AMD MCE features"
1014 depends on X86_MCE && X86_LOCAL_APIC
1016 Additional support for AMD specific MCE features such as
1017 the DRAM Error Threshold.
1019 config X86_ANCIENT_MCE
1020 bool "Support for old Pentium 5 / WinChip machine checks"
1021 depends on X86_32 && X86_MCE
1023 Include support for machine check handling on old Pentium 5 or WinChip
1024 systems. These typically need to be enabled explicitly on the command
1027 config X86_MCE_THRESHOLD
1028 depends on X86_MCE_AMD || X86_MCE_INTEL
1031 config X86_MCE_INJECT
1033 tristate "Machine check injector support"
1035 Provide support for injecting machine checks for testing purposes.
1036 If you don't know what a machine check is and you don't do kernel
1037 QA it is safe to say n.
1039 config X86_THERMAL_VECTOR
1041 depends on X86_MCE_INTEL
1043 source "arch/x86/events/Kconfig"
1045 config X86_LEGACY_VM86
1046 bool "Legacy VM86 support"
1050 This option allows user programs to put the CPU into V8086
1051 mode, which is an 80286-era approximation of 16-bit real mode.
1053 Some very old versions of X and/or vbetool require this option
1054 for user mode setting. Similarly, DOSEMU will use it if
1055 available to accelerate real mode DOS programs. However, any
1056 recent version of DOSEMU, X, or vbetool should be fully
1057 functional even without kernel VM86 support, as they will all
1058 fall back to software emulation. Nevertheless, if you are using
1059 a 16-bit DOS program where 16-bit performance matters, vm86
1060 mode might be faster than emulation and you might want to
1063 Note that any app that works on a 64-bit kernel is unlikely to
1064 need this option, as 64-bit kernels don't, and can't, support
1065 V8086 mode. This option is also unrelated to 16-bit protected
1066 mode and is not needed to run most 16-bit programs under Wine.
1068 Enabling this option increases the complexity of the kernel
1069 and slows down exception handling a tiny bit.
1071 If unsure, say N here.
1075 default X86_LEGACY_VM86
1078 bool "Enable support for 16-bit segments" if EXPERT
1080 depends on MODIFY_LDT_SYSCALL
1082 This option is required by programs like Wine to run 16-bit
1083 protected mode legacy code on x86 processors. Disabling
1084 this option saves about 300 bytes on i386, or around 6K text
1085 plus 16K runtime memory on x86-64,
1089 depends on X86_16BIT && X86_32
1093 depends on X86_16BIT && X86_64
1095 config X86_VSYSCALL_EMULATION
1096 bool "Enable vsyscall emulation" if EXPERT
1100 This enables emulation of the legacy vsyscall page. Disabling
1101 it is roughly equivalent to booting with vsyscall=none, except
1102 that it will also disable the helpful warning if a program
1103 tries to use a vsyscall. With this option set to N, offending
1104 programs will just segfault, citing addresses of the form
1107 This option is required by many programs built before 2013, and
1108 care should be used even with newer programs if set to N.
1110 Disabling this option saves about 7K of kernel size and
1111 possibly 4K of additional runtime pagetable memory.
1114 tristate "Toshiba Laptop support"
1117 This adds a driver to safely access the System Management Mode of
1118 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1119 not work on models with a Phoenix BIOS. The System Management Mode
1120 is used to set the BIOS and power saving options on Toshiba portables.
1122 For information on utilities to make use of this driver see the
1123 Toshiba Linux utilities web site at:
1124 <http://www.buzzard.org.uk/toshiba/>.
1126 Say Y if you intend to run this kernel on a Toshiba portable.
1130 tristate "Dell i8k legacy laptop support"
1132 select SENSORS_DELL_SMM
1134 This option enables legacy /proc/i8k userspace interface in hwmon
1135 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1136 temperature and allows controlling fan speeds of Dell laptops via
1137 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1138 it reports also power and hotkey status. For fan speed control is
1139 needed userspace package i8kutils.
1141 Say Y if you intend to run this kernel on old Dell laptops or want to
1142 use userspace package i8kutils.
1145 config X86_REBOOTFIXUPS
1146 bool "Enable X86 board specific fixups for reboot"
1149 This enables chipset and/or board specific fixups to be done
1150 in order to get reboot to work correctly. This is only needed on
1151 some combinations of hardware and BIOS. The symptom, for which
1152 this config is intended, is when reboot ends with a stalled/hung
1155 Currently, the only fixup is for the Geode machines using
1156 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1158 Say Y if you want to enable the fixup. Currently, it's safe to
1159 enable this option even if you don't need it.
1163 bool "CPU microcode loading support"
1165 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1168 If you say Y here, you will be able to update the microcode on
1169 Intel and AMD processors. The Intel support is for the IA32 family,
1170 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1171 AMD support is for families 0x10 and later. You will obviously need
1172 the actual microcode binary data itself which is not shipped with
1175 The preferred method to load microcode from a detached initrd is described
1176 in Documentation/x86/early-microcode.txt. For that you need to enable
1177 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1178 initrd for microcode blobs.
1180 In addition, you can build-in the microcode into the kernel. For that you
1181 need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
1182 to the CONFIG_EXTRA_FIRMWARE config option.
1184 config MICROCODE_INTEL
1185 bool "Intel microcode loading support"
1186 depends on MICROCODE
1190 This options enables microcode patch loading support for Intel
1193 For the current Intel microcode data package go to
1194 <https://downloadcenter.intel.com> and search for
1195 'Linux Processor Microcode Data File'.
1197 config MICROCODE_AMD
1198 bool "AMD microcode loading support"
1199 depends on MICROCODE
1202 If you select this option, microcode patch loading support for AMD
1203 processors will be enabled.
1205 config MICROCODE_OLD_INTERFACE
1207 depends on MICROCODE
1210 tristate "/dev/cpu/*/msr - Model-specific register support"
1212 This device gives privileged processes access to the x86
1213 Model-Specific Registers (MSRs). It is a character device with
1214 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1215 MSR accesses are directed to a specific CPU on multi-processor
1219 tristate "/dev/cpu/*/cpuid - CPU information support"
1221 This device gives processes access to the x86 CPUID instruction to
1222 be executed on a specific processor. It is a character device
1223 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1227 prompt "High Memory Support"
1234 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1235 However, the address space of 32-bit x86 processors is only 4
1236 Gigabytes large. That means that, if you have a large amount of
1237 physical memory, not all of it can be "permanently mapped" by the
1238 kernel. The physical memory that's not permanently mapped is called
1241 If you are compiling a kernel which will never run on a machine with
1242 more than 1 Gigabyte total physical RAM, answer "off" here (default
1243 choice and suitable for most users). This will result in a "3GB/1GB"
1244 split: 3GB are mapped so that each process sees a 3GB virtual memory
1245 space and the remaining part of the 4GB virtual memory space is used
1246 by the kernel to permanently map as much physical memory as
1249 If the machine has between 1 and 4 Gigabytes physical RAM, then
1252 If more than 4 Gigabytes is used then answer "64GB" here. This
1253 selection turns Intel PAE (Physical Address Extension) mode on.
1254 PAE implements 3-level paging on IA32 processors. PAE is fully
1255 supported by Linux, PAE mode is implemented on all recent Intel
1256 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1257 then the kernel will not boot on CPUs that don't support PAE!
1259 The actual amount of total physical memory will either be
1260 auto detected or can be forced by using a kernel command line option
1261 such as "mem=256M". (Try "man bootparam" or see the documentation of
1262 your boot loader (lilo or loadlin) about how to pass options to the
1263 kernel at boot time.)
1265 If unsure, say "off".
1270 Select this if you have a 32-bit processor and between 1 and 4
1271 gigabytes of physical RAM.
1278 Select this if you have a 32-bit processor and more than 4
1279 gigabytes of physical RAM.
1284 prompt "Memory split" if EXPERT
1288 Select the desired split between kernel and user memory.
1290 If the address range available to the kernel is less than the
1291 physical memory installed, the remaining memory will be available
1292 as "high memory". Accessing high memory is a little more costly
1293 than low memory, as it needs to be mapped into the kernel first.
1294 Note that increasing the kernel address space limits the range
1295 available to user programs, making the address space there
1296 tighter. Selecting anything other than the default 3G/1G split
1297 will also likely make your kernel incompatible with binary-only
1300 If you are not absolutely sure what you are doing, leave this
1304 bool "3G/1G user/kernel split"
1305 config VMSPLIT_3G_OPT
1307 bool "3G/1G user/kernel split (for full 1G low memory)"
1309 bool "2G/2G user/kernel split"
1310 config VMSPLIT_2G_OPT
1312 bool "2G/2G user/kernel split (for full 2G low memory)"
1314 bool "1G/3G user/kernel split"
1319 default 0xB0000000 if VMSPLIT_3G_OPT
1320 default 0x80000000 if VMSPLIT_2G
1321 default 0x78000000 if VMSPLIT_2G_OPT
1322 default 0x40000000 if VMSPLIT_1G
1328 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1331 bool "PAE (Physical Address Extension) Support"
1332 depends on X86_32 && !HIGHMEM4G
1335 PAE is required for NX support, and furthermore enables
1336 larger swapspace support for non-overcommit purposes. It
1337 has the cost of more pagetable lookup overhead, and also
1338 consumes more pagetable space per process.
1340 config ARCH_PHYS_ADDR_T_64BIT
1342 depends on X86_64 || X86_PAE
1344 config ARCH_DMA_ADDR_T_64BIT
1346 depends on X86_64 || HIGHMEM64G
1348 config X86_DIRECT_GBPAGES
1350 depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1352 Certain kernel features effectively disable kernel
1353 linear 1 GB mappings (even if the CPU otherwise
1354 supports them), so don't confuse the user by printing
1355 that we have them enabled.
1357 # Common NUMA Features
1359 bool "Numa Memory Allocation and Scheduler Support"
1361 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1362 default y if X86_BIGSMP
1364 Enable NUMA (Non Uniform Memory Access) support.
1366 The kernel will try to allocate memory used by a CPU on the
1367 local memory controller of the CPU and add some more
1368 NUMA awareness to the kernel.
1370 For 64-bit this is recommended if the system is Intel Core i7
1371 (or later), AMD Opteron, or EM64T NUMA.
1373 For 32-bit this is only needed if you boot a 32-bit
1374 kernel on a 64-bit NUMA platform.
1376 Otherwise, you should say N.
1380 prompt "Old style AMD Opteron NUMA detection"
1381 depends on X86_64 && NUMA && PCI
1383 Enable AMD NUMA node topology detection. You should say Y here if
1384 you have a multi processor AMD system. This uses an old method to
1385 read the NUMA configuration directly from the builtin Northbridge
1386 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1387 which also takes priority if both are compiled in.
1389 config X86_64_ACPI_NUMA
1391 prompt "ACPI NUMA detection"
1392 depends on X86_64 && NUMA && ACPI && PCI
1395 Enable ACPI SRAT based node topology detection.
1397 # Some NUMA nodes have memory ranges that span
1398 # other nodes. Even though a pfn is valid and
1399 # between a node's start and end pfns, it may not
1400 # reside on that node. See memmap_init_zone()
1402 config NODES_SPAN_OTHER_NODES
1404 depends on X86_64_ACPI_NUMA
1407 bool "NUMA emulation"
1410 Enable NUMA emulation. A flat machine will be split
1411 into virtual nodes when booted with "numa=fake=N", where N is the
1412 number of nodes. This is only useful for debugging.
1415 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1417 default "10" if MAXSMP
1418 default "6" if X86_64
1420 depends on NEED_MULTIPLE_NODES
1422 Specify the maximum number of NUMA Nodes available on the target
1423 system. Increases memory reserved to accommodate various tables.
1425 config ARCH_HAVE_MEMORY_PRESENT
1427 depends on X86_32 && DISCONTIGMEM
1429 config NEED_NODE_MEMMAP_SIZE
1431 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1433 config ARCH_FLATMEM_ENABLE
1435 depends on X86_32 && !NUMA
1437 config ARCH_DISCONTIGMEM_ENABLE
1439 depends on NUMA && X86_32
1441 config ARCH_DISCONTIGMEM_DEFAULT
1443 depends on NUMA && X86_32
1445 config ARCH_SPARSEMEM_ENABLE
1447 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1448 select SPARSEMEM_STATIC if X86_32
1449 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1451 config ARCH_SPARSEMEM_DEFAULT
1455 config ARCH_SELECT_MEMORY_MODEL
1457 depends on ARCH_SPARSEMEM_ENABLE
1459 config ARCH_MEMORY_PROBE
1460 bool "Enable sysfs memory/probe interface"
1461 depends on X86_64 && MEMORY_HOTPLUG
1463 This option enables a sysfs memory/probe interface for testing.
1464 See Documentation/memory-hotplug.txt for more information.
1465 If you are unsure how to answer this question, answer N.
1467 config ARCH_PROC_KCORE_TEXT
1469 depends on X86_64 && PROC_KCORE
1471 config ILLEGAL_POINTER_VALUE
1474 default 0xdead000000000000 if X86_64
1478 config X86_PMEM_LEGACY_DEVICE
1481 config X86_PMEM_LEGACY
1482 tristate "Support non-standard NVDIMMs and ADR protected memory"
1483 depends on PHYS_ADDR_T_64BIT
1485 select X86_PMEM_LEGACY_DEVICE
1488 Treat memory marked using the non-standard e820 type of 12 as used
1489 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1490 The kernel will offer these regions to the 'pmem' driver so
1491 they can be used for persistent storage.
1496 bool "Allocate 3rd-level pagetables from highmem"
1499 The VM uses one page table entry for each page of physical memory.
1500 For systems with a lot of RAM, this can be wasteful of precious
1501 low memory. Setting this option will put user-space page table
1502 entries in high memory.
1504 config X86_CHECK_BIOS_CORRUPTION
1505 bool "Check for low memory corruption"
1507 Periodically check for memory corruption in low memory, which
1508 is suspected to be caused by BIOS. Even when enabled in the
1509 configuration, it is disabled at runtime. Enable it by
1510 setting "memory_corruption_check=1" on the kernel command
1511 line. By default it scans the low 64k of memory every 60
1512 seconds; see the memory_corruption_check_size and
1513 memory_corruption_check_period parameters in
1514 Documentation/kernel-parameters.txt to adjust this.
1516 When enabled with the default parameters, this option has
1517 almost no overhead, as it reserves a relatively small amount
1518 of memory and scans it infrequently. It both detects corruption
1519 and prevents it from affecting the running system.
1521 It is, however, intended as a diagnostic tool; if repeatable
1522 BIOS-originated corruption always affects the same memory,
1523 you can use memmap= to prevent the kernel from using that
1526 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1527 bool "Set the default setting of memory_corruption_check"
1528 depends on X86_CHECK_BIOS_CORRUPTION
1531 Set whether the default state of memory_corruption_check is
1534 config X86_RESERVE_LOW
1535 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1539 Specify the amount of low memory to reserve for the BIOS.
1541 The first page contains BIOS data structures that the kernel
1542 must not use, so that page must always be reserved.
1544 By default we reserve the first 64K of physical RAM, as a
1545 number of BIOSes are known to corrupt that memory range
1546 during events such as suspend/resume or monitor cable
1547 insertion, so it must not be used by the kernel.
1549 You can set this to 4 if you are absolutely sure that you
1550 trust the BIOS to get all its memory reservations and usages
1551 right. If you know your BIOS have problems beyond the
1552 default 64K area, you can set this to 640 to avoid using the
1553 entire low memory range.
1555 If you have doubts about the BIOS (e.g. suspend/resume does
1556 not work or there's kernel crashes after certain hardware
1557 hotplug events) then you might want to enable
1558 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1559 typical corruption patterns.
1561 Leave this to the default value of 64 if you are unsure.
1563 config MATH_EMULATION
1565 depends on MODIFY_LDT_SYSCALL
1566 prompt "Math emulation" if X86_32
1568 Linux can emulate a math coprocessor (used for floating point
1569 operations) if you don't have one. 486DX and Pentium processors have
1570 a math coprocessor built in, 486SX and 386 do not, unless you added
1571 a 487DX or 387, respectively. (The messages during boot time can
1572 give you some hints here ["man dmesg"].) Everyone needs either a
1573 coprocessor or this emulation.
1575 If you don't have a math coprocessor, you need to say Y here; if you
1576 say Y here even though you have a coprocessor, the coprocessor will
1577 be used nevertheless. (This behavior can be changed with the kernel
1578 command line option "no387", which comes handy if your coprocessor
1579 is broken. Try "man bootparam" or see the documentation of your boot
1580 loader (lilo or loadlin) about how to pass options to the kernel at
1581 boot time.) This means that it is a good idea to say Y here if you
1582 intend to use this kernel on different machines.
1584 More information about the internals of the Linux math coprocessor
1585 emulation can be found in <file:arch/x86/math-emu/README>.
1587 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1588 kernel, it won't hurt.
1592 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1594 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1595 the Memory Type Range Registers (MTRRs) may be used to control
1596 processor access to memory ranges. This is most useful if you have
1597 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1598 allows bus write transfers to be combined into a larger transfer
1599 before bursting over the PCI/AGP bus. This can increase performance
1600 of image write operations 2.5 times or more. Saying Y here creates a
1601 /proc/mtrr file which may be used to manipulate your processor's
1602 MTRRs. Typically the X server should use this.
1604 This code has a reasonably generic interface so that similar
1605 control registers on other processors can be easily supported
1608 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1609 Registers (ARRs) which provide a similar functionality to MTRRs. For
1610 these, the ARRs are used to emulate the MTRRs.
1611 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1612 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1613 write-combining. All of these processors are supported by this code
1614 and it makes sense to say Y here if you have one of them.
1616 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1617 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1618 can lead to all sorts of problems, so it's good to say Y here.
1620 You can safely say Y even if your machine doesn't have MTRRs, you'll
1621 just add about 9 KB to your kernel.
1623 See <file:Documentation/x86/mtrr.txt> for more information.
1625 config MTRR_SANITIZER
1627 prompt "MTRR cleanup support"
1630 Convert MTRR layout from continuous to discrete, so X drivers can
1631 add writeback entries.
1633 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1634 The largest mtrr entry size for a continuous block can be set with
1639 config MTRR_SANITIZER_ENABLE_DEFAULT
1640 int "MTRR cleanup enable value (0-1)"
1643 depends on MTRR_SANITIZER
1645 Enable mtrr cleanup default value
1647 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1648 int "MTRR cleanup spare reg num (0-7)"
1651 depends on MTRR_SANITIZER
1653 mtrr cleanup spare entries default, it can be changed via
1654 mtrr_spare_reg_nr=N on the kernel command line.
1658 prompt "x86 PAT support" if EXPERT
1661 Use PAT attributes to setup page level cache control.
1663 PATs are the modern equivalents of MTRRs and are much more
1664 flexible than MTRRs.
1666 Say N here if you see bootup problems (boot crash, boot hang,
1667 spontaneous reboots) or a non-working video driver.
1671 config ARCH_USES_PG_UNCACHED
1677 prompt "x86 architectural random number generator" if EXPERT
1679 Enable the x86 architectural RDRAND instruction
1680 (Intel Bull Mountain technology) to generate random numbers.
1681 If supported, this is a high bandwidth, cryptographically
1682 secure hardware random number generator.
1686 prompt "Supervisor Mode Access Prevention" if EXPERT
1688 Supervisor Mode Access Prevention (SMAP) is a security
1689 feature in newer Intel processors. There is a small
1690 performance cost if this enabled and turned on; there is
1691 also a small increase in the kernel size if this is enabled.
1695 config X86_INTEL_MPX
1696 prompt "Intel MPX (Memory Protection Extensions)"
1698 depends on CPU_SUP_INTEL
1700 MPX provides hardware features that can be used in
1701 conjunction with compiler-instrumented code to check
1702 memory references. It is designed to detect buffer
1703 overflow or underflow bugs.
1705 This option enables running applications which are
1706 instrumented or otherwise use MPX. It does not use MPX
1707 itself inside the kernel or to protect the kernel
1708 against bad memory references.
1710 Enabling this option will make the kernel larger:
1711 ~8k of kernel text and 36 bytes of data on a 64-bit
1712 defconfig. It adds a long to the 'mm_struct' which
1713 will increase the kernel memory overhead of each
1714 process and adds some branches to paths used during
1715 exec() and munmap().
1717 For details, see Documentation/x86/intel_mpx.txt
1721 config X86_INTEL_MEMORY_PROTECTION_KEYS
1722 prompt "Intel Memory Protection Keys"
1724 # Note: only available in 64-bit mode
1725 depends on CPU_SUP_INTEL && X86_64
1727 Memory Protection Keys provides a mechanism for enforcing
1728 page-based protections, but without requiring modification of the
1729 page tables when an application changes protection domains.
1731 For details, see Documentation/x86/protection-keys.txt
1736 bool "EFI runtime service support"
1739 select EFI_RUNTIME_WRAPPERS
1741 This enables the kernel to use EFI runtime services that are
1742 available (such as the EFI variable services).
1744 This option is only useful on systems that have EFI firmware.
1745 In addition, you should use the latest ELILO loader available
1746 at <http://elilo.sourceforge.net> in order to take advantage
1747 of EFI runtime services. However, even with this option, the
1748 resultant kernel should continue to boot on existing non-EFI
1752 bool "EFI stub support"
1753 depends on EFI && !X86_USE_3DNOW
1756 This kernel feature allows a bzImage to be loaded directly
1757 by EFI firmware without the use of a bootloader.
1759 See Documentation/efi-stub.txt for more information.
1762 bool "EFI mixed-mode support"
1763 depends on EFI_STUB && X86_64
1765 Enabling this feature allows a 64-bit kernel to be booted
1766 on a 32-bit firmware, provided that your CPU supports 64-bit
1769 Note that it is not possible to boot a mixed-mode enabled
1770 kernel via the EFI boot stub - a bootloader that supports
1771 the EFI handover protocol must be used.
1777 prompt "Enable seccomp to safely compute untrusted bytecode"
1779 This kernel feature is useful for number crunching applications
1780 that may need to compute untrusted bytecode during their
1781 execution. By using pipes or other transports made available to
1782 the process as file descriptors supporting the read/write
1783 syscalls, it's possible to isolate those applications in
1784 their own address space using seccomp. Once seccomp is
1785 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1786 and the task is only allowed to execute a few safe syscalls
1787 defined by each seccomp mode.
1789 If unsure, say Y. Only embedded should say N here.
1791 source kernel/Kconfig.hz
1794 bool "kexec system call"
1797 kexec is a system call that implements the ability to shutdown your
1798 current kernel, and to start another kernel. It is like a reboot
1799 but it is independent of the system firmware. And like a reboot
1800 you can start any kernel with it, not just Linux.
1802 The name comes from the similarity to the exec system call.
1804 It is an ongoing process to be certain the hardware in a machine
1805 is properly shutdown, so do not be surprised if this code does not
1806 initially work for you. As of this writing the exact hardware
1807 interface is strongly in flux, so no good recommendation can be
1811 bool "kexec file based system call"
1816 depends on CRYPTO_SHA256=y
1818 This is new version of kexec system call. This system call is
1819 file based and takes file descriptors as system call argument
1820 for kernel and initramfs as opposed to list of segments as
1821 accepted by previous system call.
1823 config KEXEC_VERIFY_SIG
1824 bool "Verify kernel signature during kexec_file_load() syscall"
1825 depends on KEXEC_FILE
1827 This option makes kernel signature verification mandatory for
1828 the kexec_file_load() syscall.
1830 In addition to that option, you need to enable signature
1831 verification for the corresponding kernel image type being
1832 loaded in order for this to work.
1834 config KEXEC_BZIMAGE_VERIFY_SIG
1835 bool "Enable bzImage signature verification support"
1836 depends on KEXEC_VERIFY_SIG
1837 depends on SIGNED_PE_FILE_VERIFICATION
1838 select SYSTEM_TRUSTED_KEYRING
1840 Enable bzImage signature verification support.
1843 bool "kernel crash dumps"
1844 depends on X86_64 || (X86_32 && HIGHMEM)
1846 Generate crash dump after being started by kexec.
1847 This should be normally only set in special crash dump kernels
1848 which are loaded in the main kernel with kexec-tools into
1849 a specially reserved region and then later executed after
1850 a crash by kdump/kexec. The crash dump kernel must be compiled
1851 to a memory address not used by the main kernel or BIOS using
1852 PHYSICAL_START, or it must be built as a relocatable image
1853 (CONFIG_RELOCATABLE=y).
1854 For more details see Documentation/kdump/kdump.txt
1858 depends on KEXEC && HIBERNATION
1860 Jump between original kernel and kexeced kernel and invoke
1861 code in physical address mode via KEXEC
1863 config PHYSICAL_START
1864 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1867 This gives the physical address where the kernel is loaded.
1869 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1870 bzImage will decompress itself to above physical address and
1871 run from there. Otherwise, bzImage will run from the address where
1872 it has been loaded by the boot loader and will ignore above physical
1875 In normal kdump cases one does not have to set/change this option
1876 as now bzImage can be compiled as a completely relocatable image
1877 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1878 address. This option is mainly useful for the folks who don't want
1879 to use a bzImage for capturing the crash dump and want to use a
1880 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1881 to be specifically compiled to run from a specific memory area
1882 (normally a reserved region) and this option comes handy.
1884 So if you are using bzImage for capturing the crash dump,
1885 leave the value here unchanged to 0x1000000 and set
1886 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1887 for capturing the crash dump change this value to start of
1888 the reserved region. In other words, it can be set based on
1889 the "X" value as specified in the "crashkernel=YM@XM"
1890 command line boot parameter passed to the panic-ed
1891 kernel. Please take a look at Documentation/kdump/kdump.txt
1892 for more details about crash dumps.
1894 Usage of bzImage for capturing the crash dump is recommended as
1895 one does not have to build two kernels. Same kernel can be used
1896 as production kernel and capture kernel. Above option should have
1897 gone away after relocatable bzImage support is introduced. But it
1898 is present because there are users out there who continue to use
1899 vmlinux for dump capture. This option should go away down the
1902 Don't change this unless you know what you are doing.
1905 bool "Build a relocatable kernel"
1908 This builds a kernel image that retains relocation information
1909 so it can be loaded someplace besides the default 1MB.
1910 The relocations tend to make the kernel binary about 10% larger,
1911 but are discarded at runtime.
1913 One use is for the kexec on panic case where the recovery kernel
1914 must live at a different physical address than the primary
1917 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1918 it has been loaded at and the compile time physical address
1919 (CONFIG_PHYSICAL_START) is used as the minimum location.
1921 config RANDOMIZE_BASE
1922 bool "Randomize the address of the kernel image (KASLR)"
1923 depends on RELOCATABLE
1926 In support of Kernel Address Space Layout Randomization (KASLR),
1927 this randomizes the physical address at which the kernel image
1928 is decompressed and the virtual address where the kernel
1929 image is mapped, as a security feature that deters exploit
1930 attempts relying on knowledge of the location of kernel
1933 On 64-bit, the kernel physical and virtual addresses are
1934 randomized separately. The physical address will be anywhere
1935 between 16MB and the top of physical memory (up to 64TB). The
1936 virtual address will be randomized from 16MB up to 1GB (9 bits
1937 of entropy). Note that this also reduces the memory space
1938 available to kernel modules from 1.5GB to 1GB.
1940 On 32-bit, the kernel physical and virtual addresses are
1941 randomized together. They will be randomized from 16MB up to
1942 512MB (8 bits of entropy).
1944 Entropy is generated using the RDRAND instruction if it is
1945 supported. If RDTSC is supported, its value is mixed into
1946 the entropy pool as well. If neither RDRAND nor RDTSC are
1947 supported, then entropy is read from the i8254 timer. The
1948 usable entropy is limited by the kernel being built using
1949 2GB addressing, and that PHYSICAL_ALIGN must be at a
1950 minimum of 2MB. As a result, only 10 bits of entropy are
1951 theoretically possible, but the implementations are further
1952 limited due to memory layouts.
1954 If CONFIG_HIBERNATE is also enabled, KASLR is disabled at boot
1955 time. To enable it, boot with "kaslr" on the kernel command
1956 line (which will also disable hibernation).
1960 # Relocation on x86 needs some additional build support
1961 config X86_NEED_RELOCS
1963 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1965 config PHYSICAL_ALIGN
1966 hex "Alignment value to which kernel should be aligned"
1968 range 0x2000 0x1000000 if X86_32
1969 range 0x200000 0x1000000 if X86_64
1971 This value puts the alignment restrictions on physical address
1972 where kernel is loaded and run from. Kernel is compiled for an
1973 address which meets above alignment restriction.
1975 If bootloader loads the kernel at a non-aligned address and
1976 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1977 address aligned to above value and run from there.
1979 If bootloader loads the kernel at a non-aligned address and
1980 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1981 load address and decompress itself to the address it has been
1982 compiled for and run from there. The address for which kernel is
1983 compiled already meets above alignment restrictions. Hence the
1984 end result is that kernel runs from a physical address meeting
1985 above alignment restrictions.
1987 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1988 this value must be a multiple of 0x200000.
1990 Don't change this unless you know what you are doing.
1992 config RANDOMIZE_MEMORY
1993 bool "Randomize the kernel memory sections"
1995 depends on RANDOMIZE_BASE
1996 default RANDOMIZE_BASE
1998 Randomizes the base virtual address of kernel memory sections
1999 (physical memory mapping, vmalloc & vmemmap). This security feature
2000 makes exploits relying on predictable memory locations less reliable.
2002 The order of allocations remains unchanged. Entropy is generated in
2003 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2004 configuration have in average 30,000 different possible virtual
2005 addresses for each memory section.
2009 config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2010 hex "Physical memory mapping padding" if EXPERT
2011 depends on RANDOMIZE_MEMORY
2012 default "0xa" if MEMORY_HOTPLUG
2014 range 0x1 0x40 if MEMORY_HOTPLUG
2017 Define the padding in terabytes added to the existing physical
2018 memory size during kernel memory randomization. It is useful
2019 for memory hotplug support but reduces the entropy available for
2020 address randomization.
2022 If unsure, leave at the default value.
2025 bool "Support for hot-pluggable CPUs"
2028 Say Y here to allow turning CPUs off and on. CPUs can be
2029 controlled through /sys/devices/system/cpu.
2030 ( Note: power management support will enable this option
2031 automatically on SMP systems. )
2032 Say N if you want to disable CPU hotplug.
2034 config BOOTPARAM_HOTPLUG_CPU0
2035 bool "Set default setting of cpu0_hotpluggable"
2037 depends on HOTPLUG_CPU
2039 Set whether default state of cpu0_hotpluggable is on or off.
2041 Say Y here to enable CPU0 hotplug by default. If this switch
2042 is turned on, there is no need to give cpu0_hotplug kernel
2043 parameter and the CPU0 hotplug feature is enabled by default.
2045 Please note: there are two known CPU0 dependencies if you want
2046 to enable the CPU0 hotplug feature either by this switch or by
2047 cpu0_hotplug kernel parameter.
2049 First, resume from hibernate or suspend always starts from CPU0.
2050 So hibernate and suspend are prevented if CPU0 is offline.
2052 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2053 offline if any interrupt can not migrate out of CPU0. There may
2054 be other CPU0 dependencies.
2056 Please make sure the dependencies are under your control before
2057 you enable this feature.
2059 Say N if you don't want to enable CPU0 hotplug feature by default.
2060 You still can enable the CPU0 hotplug feature at boot by kernel
2061 parameter cpu0_hotplug.
2063 config DEBUG_HOTPLUG_CPU0
2065 prompt "Debug CPU0 hotplug"
2066 depends on HOTPLUG_CPU
2068 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2069 soon as possible and boots up userspace with CPU0 offlined. User
2070 can online CPU0 back after boot time.
2072 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2073 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2074 compilation or giving cpu0_hotplug kernel parameter at boot.
2080 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2081 depends on X86_32 || IA32_EMULATION
2083 Certain buggy versions of glibc will crash if they are
2084 presented with a 32-bit vDSO that is not mapped at the address
2085 indicated in its segment table.
2087 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2088 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2089 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2090 the only released version with the bug, but OpenSUSE 9
2091 contains a buggy "glibc 2.3.2".
2093 The symptom of the bug is that everything crashes on startup, saying:
2094 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2096 Saying Y here changes the default value of the vdso32 boot
2097 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2098 This works around the glibc bug but hurts performance.
2100 If unsure, say N: if you are compiling your own kernel, you
2101 are unlikely to be using a buggy version of glibc.
2104 prompt "vsyscall table for legacy applications"
2106 default LEGACY_VSYSCALL_EMULATE
2108 Legacy user code that does not know how to find the vDSO expects
2109 to be able to issue three syscalls by calling fixed addresses in
2110 kernel space. Since this location is not randomized with ASLR,
2111 it can be used to assist security vulnerability exploitation.
2113 This setting can be changed at boot time via the kernel command
2114 line parameter vsyscall=[native|emulate|none].
2116 On a system with recent enough glibc (2.14 or newer) and no
2117 static binaries, you can say None without a performance penalty
2118 to improve security.
2120 If unsure, select "Emulate".
2122 config LEGACY_VSYSCALL_NATIVE
2125 Actual executable code is located in the fixed vsyscall
2126 address mapping, implementing time() efficiently. Since
2127 this makes the mapping executable, it can be used during
2128 security vulnerability exploitation (traditionally as
2129 ROP gadgets). This configuration is not recommended.
2131 config LEGACY_VSYSCALL_EMULATE
2134 The kernel traps and emulates calls into the fixed
2135 vsyscall address mapping. This makes the mapping
2136 non-executable, but it still contains known contents,
2137 which could be used in certain rare security vulnerability
2138 exploits. This configuration is recommended when userspace
2139 still uses the vsyscall area.
2141 config LEGACY_VSYSCALL_NONE
2144 There will be no vsyscall mapping at all. This will
2145 eliminate any risk of ASLR bypass due to the vsyscall
2146 fixed address mapping. Attempts to use the vsyscalls
2147 will be reported to dmesg, so that either old or
2148 malicious userspace programs can be identified.
2153 bool "Built-in kernel command line"
2155 Allow for specifying boot arguments to the kernel at
2156 build time. On some systems (e.g. embedded ones), it is
2157 necessary or convenient to provide some or all of the
2158 kernel boot arguments with the kernel itself (that is,
2159 to not rely on the boot loader to provide them.)
2161 To compile command line arguments into the kernel,
2162 set this option to 'Y', then fill in the
2163 boot arguments in CONFIG_CMDLINE.
2165 Systems with fully functional boot loaders (i.e. non-embedded)
2166 should leave this option set to 'N'.
2169 string "Built-in kernel command string"
2170 depends on CMDLINE_BOOL
2173 Enter arguments here that should be compiled into the kernel
2174 image and used at boot time. If the boot loader provides a
2175 command line at boot time, it is appended to this string to
2176 form the full kernel command line, when the system boots.
2178 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2179 change this behavior.
2181 In most cases, the command line (whether built-in or provided
2182 by the boot loader) should specify the device for the root
2185 config CMDLINE_OVERRIDE
2186 bool "Built-in command line overrides boot loader arguments"
2187 depends on CMDLINE_BOOL
2189 Set this option to 'Y' to have the kernel ignore the boot loader
2190 command line, and use ONLY the built-in command line.
2192 This is used to work around broken boot loaders. This should
2193 be set to 'N' under normal conditions.
2195 config MODIFY_LDT_SYSCALL
2196 bool "Enable the LDT (local descriptor table)" if EXPERT
2199 Linux can allow user programs to install a per-process x86
2200 Local Descriptor Table (LDT) using the modify_ldt(2) system
2201 call. This is required to run 16-bit or segmented code such as
2202 DOSEMU or some Wine programs. It is also used by some very old
2203 threading libraries.
2205 Enabling this feature adds a small amount of overhead to
2206 context switches and increases the low-level kernel attack
2207 surface. Disabling it removes the modify_ldt(2) system call.
2209 Saying 'N' here may make sense for embedded or server kernels.
2211 source "kernel/livepatch/Kconfig"
2215 config ARCH_ENABLE_MEMORY_HOTPLUG
2217 depends on X86_64 || (X86_32 && HIGHMEM)
2219 config ARCH_ENABLE_MEMORY_HOTREMOVE
2221 depends on MEMORY_HOTPLUG
2223 config USE_PERCPU_NUMA_NODE_ID
2227 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2229 depends on X86_64 || X86_PAE
2231 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2233 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2235 menu "Power management and ACPI options"
2237 config ARCH_HIBERNATION_HEADER
2239 depends on X86_64 && HIBERNATION
2241 source "kernel/power/Kconfig"
2243 source "drivers/acpi/Kconfig"
2245 source "drivers/sfi/Kconfig"
2252 tristate "APM (Advanced Power Management) BIOS support"
2253 depends on X86_32 && PM_SLEEP
2255 APM is a BIOS specification for saving power using several different
2256 techniques. This is mostly useful for battery powered laptops with
2257 APM compliant BIOSes. If you say Y here, the system time will be
2258 reset after a RESUME operation, the /proc/apm device will provide
2259 battery status information, and user-space programs will receive
2260 notification of APM "events" (e.g. battery status change).
2262 If you select "Y" here, you can disable actual use of the APM
2263 BIOS by passing the "apm=off" option to the kernel at boot time.
2265 Note that the APM support is almost completely disabled for
2266 machines with more than one CPU.
2268 In order to use APM, you will need supporting software. For location
2269 and more information, read <file:Documentation/power/apm-acpi.txt>
2270 and the Battery Powered Linux mini-HOWTO, available from
2271 <http://www.tldp.org/docs.html#howto>.
2273 This driver does not spin down disk drives (see the hdparm(8)
2274 manpage ("man 8 hdparm") for that), and it doesn't turn off
2275 VESA-compliant "green" monitors.
2277 This driver does not support the TI 4000M TravelMate and the ACER
2278 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2279 desktop machines also don't have compliant BIOSes, and this driver
2280 may cause those machines to panic during the boot phase.
2282 Generally, if you don't have a battery in your machine, there isn't
2283 much point in using this driver and you should say N. If you get
2284 random kernel OOPSes or reboots that don't seem to be related to
2285 anything, try disabling/enabling this option (or disabling/enabling
2288 Some other things you should try when experiencing seemingly random,
2291 1) make sure that you have enough swap space and that it is
2293 2) pass the "no-hlt" option to the kernel
2294 3) switch on floating point emulation in the kernel and pass
2295 the "no387" option to the kernel
2296 4) pass the "floppy=nodma" option to the kernel
2297 5) pass the "mem=4M" option to the kernel (thereby disabling
2298 all but the first 4 MB of RAM)
2299 6) make sure that the CPU is not over clocked.
2300 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2301 8) disable the cache from your BIOS settings
2302 9) install a fan for the video card or exchange video RAM
2303 10) install a better fan for the CPU
2304 11) exchange RAM chips
2305 12) exchange the motherboard.
2307 To compile this driver as a module, choose M here: the
2308 module will be called apm.
2312 config APM_IGNORE_USER_SUSPEND
2313 bool "Ignore USER SUSPEND"
2315 This option will ignore USER SUSPEND requests. On machines with a
2316 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2317 series notebooks, it is necessary to say Y because of a BIOS bug.
2319 config APM_DO_ENABLE
2320 bool "Enable PM at boot time"
2322 Enable APM features at boot time. From page 36 of the APM BIOS
2323 specification: "When disabled, the APM BIOS does not automatically
2324 power manage devices, enter the Standby State, enter the Suspend
2325 State, or take power saving steps in response to CPU Idle calls."
2326 This driver will make CPU Idle calls when Linux is idle (unless this
2327 feature is turned off -- see "Do CPU IDLE calls", below). This
2328 should always save battery power, but more complicated APM features
2329 will be dependent on your BIOS implementation. You may need to turn
2330 this option off if your computer hangs at boot time when using APM
2331 support, or if it beeps continuously instead of suspending. Turn
2332 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2333 T400CDT. This is off by default since most machines do fine without
2338 bool "Make CPU Idle calls when idle"
2340 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2341 On some machines, this can activate improved power savings, such as
2342 a slowed CPU clock rate, when the machine is idle. These idle calls
2343 are made after the idle loop has run for some length of time (e.g.,
2344 333 mS). On some machines, this will cause a hang at boot time or
2345 whenever the CPU becomes idle. (On machines with more than one CPU,
2346 this option does nothing.)
2348 config APM_DISPLAY_BLANK
2349 bool "Enable console blanking using APM"
2351 Enable console blanking using the APM. Some laptops can use this to
2352 turn off the LCD backlight when the screen blanker of the Linux
2353 virtual console blanks the screen. Note that this is only used by
2354 the virtual console screen blanker, and won't turn off the backlight
2355 when using the X Window system. This also doesn't have anything to
2356 do with your VESA-compliant power-saving monitor. Further, this
2357 option doesn't work for all laptops -- it might not turn off your
2358 backlight at all, or it might print a lot of errors to the console,
2359 especially if you are using gpm.
2361 config APM_ALLOW_INTS
2362 bool "Allow interrupts during APM BIOS calls"
2364 Normally we disable external interrupts while we are making calls to
2365 the APM BIOS as a measure to lessen the effects of a badly behaving
2366 BIOS implementation. The BIOS should reenable interrupts if it
2367 needs to. Unfortunately, some BIOSes do not -- especially those in
2368 many of the newer IBM Thinkpads. If you experience hangs when you
2369 suspend, try setting this to Y. Otherwise, say N.
2373 source "drivers/cpufreq/Kconfig"
2375 source "drivers/cpuidle/Kconfig"
2377 source "drivers/idle/Kconfig"
2382 menu "Bus options (PCI etc.)"
2388 Find out whether you have a PCI motherboard. PCI is the name of a
2389 bus system, i.e. the way the CPU talks to the other stuff inside
2390 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2391 VESA. If you have PCI, say Y, otherwise N.
2394 prompt "PCI access mode"
2395 depends on X86_32 && PCI
2398 On PCI systems, the BIOS can be used to detect the PCI devices and
2399 determine their configuration. However, some old PCI motherboards
2400 have BIOS bugs and may crash if this is done. Also, some embedded
2401 PCI-based systems don't have any BIOS at all. Linux can also try to
2402 detect the PCI hardware directly without using the BIOS.
2404 With this option, you can specify how Linux should detect the
2405 PCI devices. If you choose "BIOS", the BIOS will be used,
2406 if you choose "Direct", the BIOS won't be used, and if you
2407 choose "MMConfig", then PCI Express MMCONFIG will be used.
2408 If you choose "Any", the kernel will try MMCONFIG, then the
2409 direct access method and falls back to the BIOS if that doesn't
2410 work. If unsure, go with the default, which is "Any".
2415 config PCI_GOMMCONFIG
2432 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2434 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2437 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2441 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2445 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2449 depends on PCI && XEN
2457 bool "Support mmconfig PCI config space access"
2458 depends on X86_64 && PCI && ACPI
2460 config PCI_CNB20LE_QUIRK
2461 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2464 Read the PCI windows out of the CNB20LE host bridge. This allows
2465 PCI hotplug to work on systems with the CNB20LE chipset which do
2468 There's no public spec for this chipset, and this functionality
2469 is known to be incomplete.
2471 You should say N unless you know you need this.
2473 source "drivers/pci/Kconfig"
2476 bool "ISA-style bus support on modern systems" if EXPERT
2479 Enables ISA-style drivers on modern systems. This is necessary to
2480 support PC/104 devices on X86_64 platforms.
2484 # x86_64 have no ISA slots, but can have ISA-style DMA.
2486 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2489 Enables ISA-style DMA support for devices requiring such controllers.
2497 Find out whether you have ISA slots on your motherboard. ISA is the
2498 name of a bus system, i.e. the way the CPU talks to the other stuff
2499 inside your box. Other bus systems are PCI, EISA, MicroChannel
2500 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2501 newer boards don't support it. If you have ISA, say Y, otherwise N.
2507 The Extended Industry Standard Architecture (EISA) bus was
2508 developed as an open alternative to the IBM MicroChannel bus.
2510 The EISA bus provided some of the features of the IBM MicroChannel
2511 bus while maintaining backward compatibility with cards made for
2512 the older ISA bus. The EISA bus saw limited use between 1988 and
2513 1995 when it was made obsolete by the PCI bus.
2515 Say Y here if you are building a kernel for an EISA-based machine.
2519 source "drivers/eisa/Kconfig"
2522 tristate "NatSemi SCx200 support"
2524 This provides basic support for National Semiconductor's
2525 (now AMD's) Geode processors. The driver probes for the
2526 PCI-IDs of several on-chip devices, so its a good dependency
2527 for other scx200_* drivers.
2529 If compiled as a module, the driver is named scx200.
2531 config SCx200HR_TIMER
2532 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2536 This driver provides a clocksource built upon the on-chip
2537 27MHz high-resolution timer. Its also a workaround for
2538 NSC Geode SC-1100's buggy TSC, which loses time when the
2539 processor goes idle (as is done by the scheduler). The
2540 other workaround is idle=poll boot option.
2543 bool "One Laptop Per Child support"
2550 Add support for detecting the unique features of the OLPC
2554 bool "OLPC XO-1 Power Management"
2555 depends on OLPC && MFD_CS5535 && PM_SLEEP
2558 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2561 bool "OLPC XO-1 Real Time Clock"
2562 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2564 Add support for the XO-1 real time clock, which can be used as a
2565 programmable wakeup source.
2568 bool "OLPC XO-1 SCI extras"
2569 depends on OLPC && OLPC_XO1_PM
2575 Add support for SCI-based features of the OLPC XO-1 laptop:
2576 - EC-driven system wakeups
2580 - AC adapter status updates
2581 - Battery status updates
2583 config OLPC_XO15_SCI
2584 bool "OLPC XO-1.5 SCI extras"
2585 depends on OLPC && ACPI
2588 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2589 - EC-driven system wakeups
2590 - AC adapter status updates
2591 - Battery status updates
2594 bool "PCEngines ALIX System Support (LED setup)"
2597 This option enables system support for the PCEngines ALIX.
2598 At present this just sets up LEDs for GPIO control on
2599 ALIX2/3/6 boards. However, other system specific setup should
2602 Note: You must still enable the drivers for GPIO and LED support
2603 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2605 Note: You have to set alix.force=1 for boards with Award BIOS.
2608 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2611 This option enables system support for the Soekris Engineering net5501.
2614 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2618 This option enables system support for the Traverse Technologies GEOS.
2621 bool "Technologic Systems TS-5500 platform support"
2623 select CHECK_SIGNATURE
2627 This option enables system support for the Technologic Systems TS-5500.
2633 depends on CPU_SUP_AMD && PCI
2635 source "drivers/pcmcia/Kconfig"
2638 tristate "RapidIO support"
2642 If enabled this option will include drivers and the core
2643 infrastructure code to support RapidIO interconnect devices.
2645 source "drivers/rapidio/Kconfig"
2648 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2650 Firmwares often provide initial graphics framebuffers so the BIOS,
2651 bootloader or kernel can show basic video-output during boot for
2652 user-guidance and debugging. Historically, x86 used the VESA BIOS
2653 Extensions and EFI-framebuffers for this, which are mostly limited
2655 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2656 framebuffers so the new generic system-framebuffer drivers can be
2657 used on x86. If the framebuffer is not compatible with the generic
2658 modes, it is adverticed as fallback platform framebuffer so legacy
2659 drivers like efifb, vesafb and uvesafb can pick it up.
2660 If this option is not selected, all system framebuffers are always
2661 marked as fallback platform framebuffers as usual.
2663 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2664 not be able to pick up generic system framebuffers if this option
2665 is selected. You are highly encouraged to enable simplefb as
2666 replacement if you select this option. simplefb can correctly deal
2667 with generic system framebuffers. But you should still keep vesafb
2668 and others enabled as fallback if a system framebuffer is
2669 incompatible with simplefb.
2676 menu "Executable file formats / Emulations"
2678 source "fs/Kconfig.binfmt"
2680 config IA32_EMULATION
2681 bool "IA32 Emulation"
2684 select COMPAT_BINFMT_ELF
2685 select ARCH_WANT_OLD_COMPAT_IPC
2687 Include code to run legacy 32-bit programs under a
2688 64-bit kernel. You should likely turn this on, unless you're
2689 100% sure that you don't have any 32-bit programs left.
2692 tristate "IA32 a.out support"
2693 depends on IA32_EMULATION
2695 Support old a.out binaries in the 32bit emulation.
2698 bool "x32 ABI for 64-bit mode"
2701 Include code to run binaries for the x32 native 32-bit ABI
2702 for 64-bit processors. An x32 process gets access to the
2703 full 64-bit register file and wide data path while leaving
2704 pointers at 32 bits for smaller memory footprint.
2706 You will need a recent binutils (2.22 or later) with
2707 elf32_x86_64 support enabled to compile a kernel with this
2712 depends on IA32_EMULATION || X86_X32
2715 config COMPAT_FOR_U64_ALIGNMENT
2718 config SYSVIPC_COMPAT
2730 config HAVE_ATOMIC_IOMAP
2734 config X86_DEV_DMA_OPS
2736 depends on X86_64 || STA2X11
2738 config X86_DMA_REMAP
2748 tristate "Volume Management Device Driver"
2751 Adds support for the Intel Volume Management Device (VMD). VMD is a
2752 secondary PCI host bridge that allows PCI Express root ports,
2753 and devices attached to them, to be removed from the default
2754 PCI domain and placed within the VMD domain. This provides
2755 more bus resources than are otherwise possible with a
2756 single domain. If you know your system provides one of these and
2757 has devices attached to it, say Y; if you are not sure, say N.
2759 source "net/Kconfig"
2761 source "drivers/Kconfig"
2763 source "drivers/firmware/Kconfig"
2767 source "arch/x86/Kconfig.debug"
2769 source "security/Kconfig"
2771 source "crypto/Kconfig"
2773 source "arch/x86/kvm/Kconfig"
2775 source "lib/Kconfig"