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_DEVMEM_IS_ALLOWED
28 select ARCH_HAS_ELF_RANDOMIZE
29 select ARCH_HAS_FAST_MULTIPLIER
30 select ARCH_HAS_GCOV_PROFILE_ALL
31 select ARCH_HAS_KCOV if X86_64
32 select ARCH_HAS_PMEM_API if X86_64
33 select ARCH_HAS_MMIO_FLUSH
34 select ARCH_HAS_SG_CHAIN
35 select ARCH_HAS_UBSAN_SANITIZE_ALL
36 select ARCH_HAVE_NMI_SAFE_CMPXCHG
37 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
38 select ARCH_MIGHT_HAVE_PC_PARPORT
39 select ARCH_MIGHT_HAVE_PC_SERIO
40 select ARCH_SUPPORTS_ATOMIC_RMW
41 select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
42 select ARCH_SUPPORTS_INT128 if X86_64
43 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
44 select ARCH_USE_BUILTIN_BSWAP
45 select ARCH_USE_CMPXCHG_LOCKREF if X86_64
46 select ARCH_USE_QUEUED_RWLOCKS
47 select ARCH_USE_QUEUED_SPINLOCKS
48 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if SMP
49 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
50 select ARCH_WANT_FRAME_POINTERS
51 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
52 select ARCH_WANT_OPTIONAL_GPIOLIB
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_GENERIC_DMA_COHERENT if X86_32
115 select HAVE_HW_BREAKPOINT
117 select HAVE_IOREMAP_PROT
118 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
119 select HAVE_IRQ_TIME_ACCOUNTING
120 select HAVE_KERNEL_BZIP2
121 select HAVE_KERNEL_GZIP
122 select HAVE_KERNEL_LZ4
123 select HAVE_KERNEL_LZMA
124 select HAVE_KERNEL_LZO
125 select HAVE_KERNEL_XZ
127 select HAVE_KPROBES_ON_FTRACE
128 select HAVE_KRETPROBES
130 select HAVE_LIVEPATCH if X86_64
132 select HAVE_MEMBLOCK_NODE_MAP
133 select HAVE_MIXED_BREAKPOINTS_REGS
136 select HAVE_OPTPROBES
137 select HAVE_PCSPKR_PLATFORM
138 select HAVE_PERF_EVENTS
139 select HAVE_PERF_EVENTS_NMI
140 select HAVE_PERF_REGS
141 select HAVE_PERF_USER_STACK_DUMP
142 select HAVE_REGS_AND_STACK_ACCESS_API
143 select HAVE_SYSCALL_TRACEPOINTS
144 select HAVE_UID16 if X86_32 || IA32_EMULATION
145 select HAVE_UNSTABLE_SCHED_CLOCK
146 select HAVE_USER_RETURN_NOTIFIER
147 select IRQ_FORCED_THREADING
148 select MODULES_USE_ELF_RELA if X86_64
149 select MODULES_USE_ELF_REL if X86_32
150 select OLD_SIGACTION if X86_32
151 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
156 select SYSCTL_EXCEPTION_TRACE
157 select USER_STACKTRACE_SUPPORT
159 select X86_DEV_DMA_OPS if X86_64
160 select X86_FEATURE_NAMES if PROC_FS
161 select HAVE_STACK_VALIDATION if X86_64
162 select ARCH_USES_HIGH_VMA_FLAGS if X86_INTEL_MEMORY_PROTECTION_KEYS
163 select ARCH_HAS_PKEYS if X86_INTEL_MEMORY_PROTECTION_KEYS
165 config INSTRUCTION_DECODER
167 depends on KPROBES || PERF_EVENTS || UPROBES
171 default "elf32-i386" if X86_32
172 default "elf64-x86-64" if X86_64
174 config ARCH_DEFCONFIG
176 default "arch/x86/configs/i386_defconfig" if X86_32
177 default "arch/x86/configs/x86_64_defconfig" if X86_64
179 config LOCKDEP_SUPPORT
182 config STACKTRACE_SUPPORT
188 config ARCH_MMAP_RND_BITS_MIN
192 config ARCH_MMAP_RND_BITS_MAX
196 config ARCH_MMAP_RND_COMPAT_BITS_MIN
199 config ARCH_MMAP_RND_COMPAT_BITS_MAX
205 config NEED_DMA_MAP_STATE
207 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
209 config NEED_SG_DMA_LENGTH
212 config GENERIC_ISA_DMA
214 depends on ISA_DMA_API
219 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
221 config GENERIC_BUG_RELATIVE_POINTERS
224 config GENERIC_HWEIGHT
227 config ARCH_MAY_HAVE_PC_FDC
229 depends on ISA_DMA_API
231 config RWSEM_XCHGADD_ALGORITHM
234 config GENERIC_CALIBRATE_DELAY
237 config ARCH_HAS_CPU_RELAX
240 config ARCH_HAS_CACHE_LINE_SIZE
243 config HAVE_SETUP_PER_CPU_AREA
246 config NEED_PER_CPU_EMBED_FIRST_CHUNK
249 config NEED_PER_CPU_PAGE_FIRST_CHUNK
252 config ARCH_HIBERNATION_POSSIBLE
255 config ARCH_SUSPEND_POSSIBLE
258 config ARCH_WANT_HUGE_PMD_SHARE
261 config ARCH_WANT_GENERAL_HUGETLB
270 config ARCH_SUPPORTS_OPTIMIZED_INLINING
273 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
276 config KASAN_SHADOW_OFFSET
279 default 0xdffffc0000000000
281 config HAVE_INTEL_TXT
283 depends on INTEL_IOMMU && ACPI
287 depends on X86_32 && SMP
291 depends on X86_64 && SMP
293 config X86_32_LAZY_GS
295 depends on X86_32 && !CC_STACKPROTECTOR
297 config ARCH_HWEIGHT_CFLAGS
299 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
300 default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64
302 config ARCH_SUPPORTS_UPROBES
305 config FIX_EARLYCON_MEM
311 config PGTABLE_LEVELS
317 source "init/Kconfig"
318 source "kernel/Kconfig.freezer"
320 menu "Processor type and features"
323 bool "DMA memory allocation support" if EXPERT
326 DMA memory allocation support allows devices with less than 32-bit
327 addressing to allocate within the first 16MB of address space.
328 Disable if no such devices will be used.
333 bool "Symmetric multi-processing support"
335 This enables support for systems with more than one CPU. If you have
336 a system with only one CPU, say N. If you have a system with more
339 If you say N here, the kernel will run on uni- and multiprocessor
340 machines, but will use only one CPU of a multiprocessor machine. If
341 you say Y here, the kernel will run on many, but not all,
342 uniprocessor machines. On a uniprocessor machine, the kernel
343 will run faster if you say N here.
345 Note that if you say Y here and choose architecture "586" or
346 "Pentium" under "Processor family", the kernel will not work on 486
347 architectures. Similarly, multiprocessor kernels for the "PPro"
348 architecture may not work on all Pentium based boards.
350 People using multiprocessor machines who say Y here should also say
351 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
352 Management" code will be disabled if you say Y here.
354 See also <file:Documentation/x86/i386/IO-APIC.txt>,
355 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
356 <http://www.tldp.org/docs.html#howto>.
358 If you don't know what to do here, say N.
360 config X86_FEATURE_NAMES
361 bool "Processor feature human-readable names" if EMBEDDED
364 This option compiles in a table of x86 feature bits and corresponding
365 names. This is required to support /proc/cpuinfo and a few kernel
366 messages. You can disable this to save space, at the expense of
367 making those few kernel messages show numeric feature bits instead.
371 config X86_FAST_FEATURE_TESTS
372 bool "Fast CPU feature tests" if EMBEDDED
375 Some fast-paths in the kernel depend on the capabilities of the CPU.
376 Say Y here for the kernel to patch in the appropriate code at runtime
377 based on the capabilities of the CPU. The infrastructure for patching
378 code at runtime takes up some additional space; space-constrained
379 embedded systems may wish to say N here to produce smaller, slightly
383 bool "Support x2apic"
384 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
386 This enables x2apic support on CPUs that have this feature.
388 This allows 32-bit apic IDs (so it can support very large systems),
389 and accesses the local apic via MSRs not via mmio.
391 If you don't know what to do here, say N.
394 bool "Enable MPS table" if ACPI || SFI
396 depends on X86_LOCAL_APIC
398 For old smp systems that do not have proper acpi support. Newer systems
399 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
402 bool "Support for big SMP systems with more than 8 CPUs"
403 depends on X86_32 && SMP
405 This option is needed for the systems that have more than 8 CPUs
409 depends on X86_GOLDFISH
412 config X86_EXTENDED_PLATFORM
413 bool "Support for extended (non-PC) x86 platforms"
416 If you disable this option then the kernel will only support
417 standard PC platforms. (which covers the vast majority of
420 If you enable this option then you'll be able to select support
421 for the following (non-PC) 32 bit x86 platforms:
422 Goldfish (Android emulator)
425 SGI 320/540 (Visual Workstation)
426 STA2X11-based (e.g. Northville)
427 Moorestown MID devices
429 If you have one of these systems, or if you want to build a
430 generic distribution kernel, say Y here - otherwise say N.
434 config X86_EXTENDED_PLATFORM
435 bool "Support for extended (non-PC) x86 platforms"
438 If you disable this option then the kernel will only support
439 standard PC platforms. (which covers the vast majority of
442 If you enable this option then you'll be able to select support
443 for the following (non-PC) 64 bit x86 platforms:
448 If you have one of these systems, or if you want to build a
449 generic distribution kernel, say Y here - otherwise say N.
451 # This is an alphabetically sorted list of 64 bit extended platforms
452 # Please maintain the alphabetic order if and when there are additions
454 bool "Numascale NumaChip"
456 depends on X86_EXTENDED_PLATFORM
459 depends on X86_X2APIC
460 depends on PCI_MMCONFIG
462 Adds support for Numascale NumaChip large-SMP systems. Needed to
463 enable more than ~168 cores.
464 If you don't have one of these, you should say N here.
468 select HYPERVISOR_GUEST
470 depends on X86_64 && PCI
471 depends on X86_EXTENDED_PLATFORM
474 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
475 supposed to run on these EM64T-based machines. Only choose this option
476 if you have one of these machines.
479 bool "SGI Ultraviolet"
481 depends on X86_EXTENDED_PLATFORM
484 depends on X86_X2APIC
487 This option is needed in order to support SGI Ultraviolet systems.
488 If you don't have one of these, you should say N here.
490 # Following is an alphabetically sorted list of 32 bit extended platforms
491 # Please maintain the alphabetic order if and when there are additions
494 bool "Goldfish (Virtual Platform)"
495 depends on X86_EXTENDED_PLATFORM
497 Enable support for the Goldfish virtual platform used primarily
498 for Android development. Unless you are building for the Android
499 Goldfish emulator say N here.
502 bool "CE4100 TV platform"
504 depends on PCI_GODIRECT
505 depends on X86_IO_APIC
507 depends on X86_EXTENDED_PLATFORM
508 select X86_REBOOTFIXUPS
510 select OF_EARLY_FLATTREE
512 Select for the Intel CE media processor (CE4100) SOC.
513 This option compiles in support for the CE4100 SOC for settop
514 boxes and media devices.
517 bool "Intel MID platform support"
518 depends on X86_EXTENDED_PLATFORM
519 depends on X86_PLATFORM_DEVICES
521 depends on X86_64 || (PCI_GOANY && X86_32)
522 depends on X86_IO_APIC
528 select MFD_INTEL_MSIC
530 Select to build a kernel capable of supporting Intel MID (Mobile
531 Internet Device) platform systems which do not have the PCI legacy
532 interfaces. If you are building for a PC class system say N here.
534 Intel MID platforms are based on an Intel processor and chipset which
535 consume less power than most of the x86 derivatives.
537 config X86_INTEL_QUARK
538 bool "Intel Quark platform support"
540 depends on X86_EXTENDED_PLATFORM
541 depends on X86_PLATFORM_DEVICES
545 depends on X86_IO_APIC
550 Select to include support for Quark X1000 SoC.
551 Say Y here if you have a Quark based system such as the Arduino
552 compatible Intel Galileo.
554 config X86_INTEL_LPSS
555 bool "Intel Low Power Subsystem Support"
556 depends on X86 && ACPI
561 Select to build support for Intel Low Power Subsystem such as
562 found on Intel Lynxpoint PCH. Selecting this option enables
563 things like clock tree (common clock framework) and pincontrol
564 which are needed by the LPSS peripheral drivers.
566 config X86_AMD_PLATFORM_DEVICE
567 bool "AMD ACPI2Platform devices support"
572 Select to interpret AMD specific ACPI device to platform device
573 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
574 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
575 implemented under PINCTRL subsystem.
578 tristate "Intel SoC IOSF Sideband support for SoC platforms"
581 This option enables sideband register access support for Intel SoC
582 platforms. On these platforms the IOSF sideband is used in lieu of
583 MSR's for some register accesses, mostly but not limited to thermal
584 and power. Drivers may query the availability of this device to
585 determine if they need the sideband in order to work on these
586 platforms. The sideband is available on the following SoC products.
587 This list is not meant to be exclusive.
592 You should say Y if you are running a kernel on one of these SoC's.
594 config IOSF_MBI_DEBUG
595 bool "Enable IOSF sideband access through debugfs"
596 depends on IOSF_MBI && DEBUG_FS
598 Select this option to expose the IOSF sideband access registers (MCR,
599 MDR, MCRX) through debugfs to write and read register information from
600 different units on the SoC. This is most useful for obtaining device
601 state information for debug and analysis. As this is a general access
602 mechanism, users of this option would have specific knowledge of the
603 device they want to access.
605 If you don't require the option or are in doubt, say N.
608 bool "RDC R-321x SoC"
610 depends on X86_EXTENDED_PLATFORM
612 select X86_REBOOTFIXUPS
614 This option is needed for RDC R-321x system-on-chip, also known
616 If you don't have one of these chips, you should say N here.
618 config X86_32_NON_STANDARD
619 bool "Support non-standard 32-bit SMP architectures"
620 depends on X86_32 && SMP
621 depends on X86_EXTENDED_PLATFORM
623 This option compiles in the bigsmp and STA2X11 default
624 subarchitectures. It is intended for a generic binary
625 kernel. If you select them all, kernel will probe it one by
626 one and will fallback to default.
628 # Alphabetically sorted list of Non standard 32 bit platforms
630 config X86_SUPPORTS_MEMORY_FAILURE
632 # MCE code calls memory_failure():
634 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
635 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
636 depends on X86_64 || !SPARSEMEM
637 select ARCH_SUPPORTS_MEMORY_FAILURE
640 bool "STA2X11 Companion Chip Support"
641 depends on X86_32_NON_STANDARD && PCI
642 select X86_DEV_DMA_OPS
646 select ARCH_REQUIRE_GPIOLIB
649 This adds support for boards based on the STA2X11 IO-Hub,
650 a.k.a. "ConneXt". The chip is used in place of the standard
651 PC chipset, so all "standard" peripherals are missing. If this
652 option is selected the kernel will still be able to boot on
653 standard PC machines.
656 tristate "Eurobraille/Iris poweroff module"
659 The Iris machines from EuroBraille do not have APM or ACPI support
660 to shut themselves down properly. A special I/O sequence is
661 needed to do so, which is what this module does at
664 This is only for Iris machines from EuroBraille.
668 config SCHED_OMIT_FRAME_POINTER
670 prompt "Single-depth WCHAN output"
673 Calculate simpler /proc/<PID>/wchan values. If this option
674 is disabled then wchan values will recurse back to the
675 caller function. This provides more accurate wchan values,
676 at the expense of slightly more scheduling overhead.
678 If in doubt, say "Y".
680 menuconfig HYPERVISOR_GUEST
681 bool "Linux guest support"
683 Say Y here to enable options for running Linux under various hyper-
684 visors. This option enables basic hypervisor detection and platform
687 If you say N, all options in this submenu will be skipped and
688 disabled, and Linux guest support won't be built in.
693 bool "Enable paravirtualization code"
695 This changes the kernel so it can modify itself when it is run
696 under a hypervisor, potentially improving performance significantly
697 over full virtualization. However, when run without a hypervisor
698 the kernel is theoretically slower and slightly larger.
700 config PARAVIRT_DEBUG
701 bool "paravirt-ops debugging"
702 depends on PARAVIRT && DEBUG_KERNEL
704 Enable to debug paravirt_ops internals. Specifically, BUG if
705 a paravirt_op is missing when it is called.
707 config PARAVIRT_SPINLOCKS
708 bool "Paravirtualization layer for spinlocks"
709 depends on PARAVIRT && SMP
710 select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS
712 Paravirtualized spinlocks allow a pvops backend to replace the
713 spinlock implementation with something virtualization-friendly
714 (for example, block the virtual CPU rather than spinning).
716 It has a minimal impact on native kernels and gives a nice performance
717 benefit on paravirtualized KVM / Xen kernels.
719 If you are unsure how to answer this question, answer Y.
721 config QUEUED_LOCK_STAT
722 bool "Paravirt queued spinlock statistics"
723 depends on PARAVIRT_SPINLOCKS && DEBUG_FS && QUEUED_SPINLOCKS
725 Enable the collection of statistical data on the slowpath
726 behavior of paravirtualized queued spinlocks and report
729 source "arch/x86/xen/Kconfig"
732 bool "KVM Guest support (including kvmclock)"
734 select PARAVIRT_CLOCK
737 This option enables various optimizations for running under the KVM
738 hypervisor. It includes a paravirtualized clock, so that instead
739 of relying on a PIT (or probably other) emulation by the
740 underlying device model, the host provides the guest with
741 timing infrastructure such as time of day, and system time
744 bool "Enable debug information for KVM Guests in debugfs"
745 depends on KVM_GUEST && DEBUG_FS
748 This option enables collection of various statistics for KVM guest.
749 Statistics are displayed in debugfs filesystem. Enabling this option
750 may incur significant overhead.
752 source "arch/x86/lguest/Kconfig"
754 config PARAVIRT_TIME_ACCOUNTING
755 bool "Paravirtual steal time accounting"
759 Select this option to enable fine granularity task steal time
760 accounting. Time spent executing other tasks in parallel with
761 the current vCPU is discounted from the vCPU power. To account for
762 that, there can be a small performance impact.
764 If in doubt, say N here.
766 config PARAVIRT_CLOCK
769 endif #HYPERVISOR_GUEST
774 source "arch/x86/Kconfig.cpu"
778 prompt "HPET Timer Support" if X86_32
780 Use the IA-PC HPET (High Precision Event Timer) to manage
781 time in preference to the PIT and RTC, if a HPET is
783 HPET is the next generation timer replacing legacy 8254s.
784 The HPET provides a stable time base on SMP
785 systems, unlike the TSC, but it is more expensive to access,
786 as it is off-chip. The interface used is documented
787 in the HPET spec, revision 1.
789 You can safely choose Y here. However, HPET will only be
790 activated if the platform and the BIOS support this feature.
791 Otherwise the 8254 will be used for timing services.
793 Choose N to continue using the legacy 8254 timer.
795 config HPET_EMULATE_RTC
797 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
800 def_bool y if X86_INTEL_MID
801 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
803 depends on X86_INTEL_MID && SFI
805 APB timer is the replacement for 8254, HPET on X86 MID platforms.
806 The APBT provides a stable time base on SMP
807 systems, unlike the TSC, but it is more expensive to access,
808 as it is off-chip. APB timers are always running regardless of CPU
809 C states, they are used as per CPU clockevent device when possible.
811 # Mark as expert because too many people got it wrong.
812 # The code disables itself when not needed.
815 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
816 bool "Enable DMI scanning" if EXPERT
818 Enabled scanning of DMI to identify machine quirks. Say Y
819 here unless you have verified that your setup is not
820 affected by entries in the DMI blacklist. Required by PNP
824 bool "Old AMD GART IOMMU support"
826 depends on X86_64 && PCI && AMD_NB
828 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
829 GART based hardware IOMMUs.
831 The GART supports full DMA access for devices with 32-bit access
832 limitations, on systems with more than 3 GB. This is usually needed
833 for USB, sound, many IDE/SATA chipsets and some other devices.
835 Newer systems typically have a modern AMD IOMMU, supported via
836 the CONFIG_AMD_IOMMU=y config option.
838 In normal configurations this driver is only active when needed:
839 there's more than 3 GB of memory and the system contains a
840 32-bit limited device.
845 bool "IBM Calgary IOMMU support"
847 depends on X86_64 && PCI
849 Support for hardware IOMMUs in IBM's xSeries x366 and x460
850 systems. Needed to run systems with more than 3GB of memory
851 properly with 32-bit PCI devices that do not support DAC
852 (Double Address Cycle). Calgary also supports bus level
853 isolation, where all DMAs pass through the IOMMU. This
854 prevents them from going anywhere except their intended
855 destination. This catches hard-to-find kernel bugs and
856 mis-behaving drivers and devices that do not use the DMA-API
857 properly to set up their DMA buffers. The IOMMU can be
858 turned off at boot time with the iommu=off parameter.
859 Normally the kernel will make the right choice by itself.
862 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
864 prompt "Should Calgary be enabled by default?"
865 depends on CALGARY_IOMMU
867 Should Calgary be enabled by default? if you choose 'y', Calgary
868 will be used (if it exists). If you choose 'n', Calgary will not be
869 used even if it exists. If you choose 'n' and would like to use
870 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
873 # need this always selected by IOMMU for the VIA workaround
877 Support for software bounce buffers used on x86-64 systems
878 which don't have a hardware IOMMU. Using this PCI devices
879 which can only access 32-bits of memory can be used on systems
880 with more than 3 GB of memory.
885 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
888 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
889 depends on X86_64 && SMP && DEBUG_KERNEL
890 select CPUMASK_OFFSTACK
892 Enable maximum number of CPUS and NUMA Nodes for this architecture.
896 int "Maximum number of CPUs" if SMP && !MAXSMP
897 range 2 8 if SMP && X86_32 && !X86_BIGSMP
898 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
899 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
901 default "8192" if MAXSMP
902 default "32" if SMP && X86_BIGSMP
903 default "8" if SMP && X86_32
906 This allows you to specify the maximum number of CPUs which this
907 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
908 supported value is 8192, otherwise the maximum value is 512. The
909 minimum value which makes sense is 2.
911 This is purely to save memory - each supported CPU adds
912 approximately eight kilobytes to the kernel image.
915 bool "SMT (Hyperthreading) scheduler support"
918 SMT scheduler support improves the CPU scheduler's decision making
919 when dealing with Intel Pentium 4 chips with HyperThreading at a
920 cost of slightly increased overhead in some places. If unsure say
925 prompt "Multi-core scheduler support"
928 Multi-core scheduler support improves the CPU scheduler's decision
929 making when dealing with multi-core CPU chips at a cost of slightly
930 increased overhead in some places. If unsure say N here.
932 source "kernel/Kconfig.preempt"
936 depends on !SMP && X86_LOCAL_APIC
939 bool "Local APIC support on uniprocessors" if !PCI_MSI
941 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
943 A local APIC (Advanced Programmable Interrupt Controller) is an
944 integrated interrupt controller in the CPU. If you have a single-CPU
945 system which has a processor with a local APIC, you can say Y here to
946 enable and use it. If you say Y here even though your machine doesn't
947 have a local APIC, then the kernel will still run with no slowdown at
948 all. The local APIC supports CPU-generated self-interrupts (timer,
949 performance counters), and the NMI watchdog which detects hard
953 bool "IO-APIC support on uniprocessors"
954 depends on X86_UP_APIC
956 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
957 SMP-capable replacement for PC-style interrupt controllers. Most
958 SMP systems and many recent uniprocessor systems have one.
960 If you have a single-CPU system with an IO-APIC, you can say Y here
961 to use it. If you say Y here even though your machine doesn't have
962 an IO-APIC, then the kernel will still run with no slowdown at all.
964 config X86_LOCAL_APIC
966 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
967 select IRQ_DOMAIN_HIERARCHY
968 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
972 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
974 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
975 bool "Reroute for broken boot IRQs"
976 depends on X86_IO_APIC
978 This option enables a workaround that fixes a source of
979 spurious interrupts. This is recommended when threaded
980 interrupt handling is used on systems where the generation of
981 superfluous "boot interrupts" cannot be disabled.
983 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
984 entry in the chipset's IO-APIC is masked (as, e.g. the RT
985 kernel does during interrupt handling). On chipsets where this
986 boot IRQ generation cannot be disabled, this workaround keeps
987 the original IRQ line masked so that only the equivalent "boot
988 IRQ" is delivered to the CPUs. The workaround also tells the
989 kernel to set up the IRQ handler on the boot IRQ line. In this
990 way only one interrupt is delivered to the kernel. Otherwise
991 the spurious second interrupt may cause the kernel to bring
992 down (vital) interrupt lines.
994 Only affects "broken" chipsets. Interrupt sharing may be
995 increased on these systems.
998 bool "Machine Check / overheating reporting"
999 select GENERIC_ALLOCATOR
1002 Machine Check support allows the processor to notify the
1003 kernel if it detects a problem (e.g. overheating, data corruption).
1004 The action the kernel takes depends on the severity of the problem,
1005 ranging from warning messages to halting the machine.
1007 config X86_MCE_INTEL
1009 prompt "Intel MCE features"
1010 depends on X86_MCE && X86_LOCAL_APIC
1012 Additional support for intel specific MCE features such as
1013 the thermal monitor.
1017 prompt "AMD MCE features"
1018 depends on X86_MCE && X86_LOCAL_APIC
1020 Additional support for AMD specific MCE features such as
1021 the DRAM Error Threshold.
1023 config X86_ANCIENT_MCE
1024 bool "Support for old Pentium 5 / WinChip machine checks"
1025 depends on X86_32 && X86_MCE
1027 Include support for machine check handling on old Pentium 5 or WinChip
1028 systems. These typically need to be enabled explicitly on the command
1031 config X86_MCE_THRESHOLD
1032 depends on X86_MCE_AMD || X86_MCE_INTEL
1035 config X86_MCE_INJECT
1037 tristate "Machine check injector support"
1039 Provide support for injecting machine checks for testing purposes.
1040 If you don't know what a machine check is and you don't do kernel
1041 QA it is safe to say n.
1043 config X86_THERMAL_VECTOR
1045 depends on X86_MCE_INTEL
1047 source "arch/x86/events/Kconfig"
1049 config X86_LEGACY_VM86
1050 bool "Legacy VM86 support"
1054 This option allows user programs to put the CPU into V8086
1055 mode, which is an 80286-era approximation of 16-bit real mode.
1057 Some very old versions of X and/or vbetool require this option
1058 for user mode setting. Similarly, DOSEMU will use it if
1059 available to accelerate real mode DOS programs. However, any
1060 recent version of DOSEMU, X, or vbetool should be fully
1061 functional even without kernel VM86 support, as they will all
1062 fall back to software emulation. Nevertheless, if you are using
1063 a 16-bit DOS program where 16-bit performance matters, vm86
1064 mode might be faster than emulation and you might want to
1067 Note that any app that works on a 64-bit kernel is unlikely to
1068 need this option, as 64-bit kernels don't, and can't, support
1069 V8086 mode. This option is also unrelated to 16-bit protected
1070 mode and is not needed to run most 16-bit programs under Wine.
1072 Enabling this option increases the complexity of the kernel
1073 and slows down exception handling a tiny bit.
1075 If unsure, say N here.
1079 default X86_LEGACY_VM86
1082 bool "Enable support for 16-bit segments" if EXPERT
1084 depends on MODIFY_LDT_SYSCALL
1086 This option is required by programs like Wine to run 16-bit
1087 protected mode legacy code on x86 processors. Disabling
1088 this option saves about 300 bytes on i386, or around 6K text
1089 plus 16K runtime memory on x86-64,
1093 depends on X86_16BIT && X86_32
1097 depends on X86_16BIT && X86_64
1099 config X86_VSYSCALL_EMULATION
1100 bool "Enable vsyscall emulation" if EXPERT
1104 This enables emulation of the legacy vsyscall page. Disabling
1105 it is roughly equivalent to booting with vsyscall=none, except
1106 that it will also disable the helpful warning if a program
1107 tries to use a vsyscall. With this option set to N, offending
1108 programs will just segfault, citing addresses of the form
1111 This option is required by many programs built before 2013, and
1112 care should be used even with newer programs if set to N.
1114 Disabling this option saves about 7K of kernel size and
1115 possibly 4K of additional runtime pagetable memory.
1118 tristate "Toshiba Laptop support"
1121 This adds a driver to safely access the System Management Mode of
1122 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1123 not work on models with a Phoenix BIOS. The System Management Mode
1124 is used to set the BIOS and power saving options on Toshiba portables.
1126 For information on utilities to make use of this driver see the
1127 Toshiba Linux utilities web site at:
1128 <http://www.buzzard.org.uk/toshiba/>.
1130 Say Y if you intend to run this kernel on a Toshiba portable.
1134 tristate "Dell i8k legacy laptop support"
1136 select SENSORS_DELL_SMM
1138 This option enables legacy /proc/i8k userspace interface in hwmon
1139 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1140 temperature and allows controlling fan speeds of Dell laptops via
1141 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1142 it reports also power and hotkey status. For fan speed control is
1143 needed userspace package i8kutils.
1145 Say Y if you intend to run this kernel on old Dell laptops or want to
1146 use userspace package i8kutils.
1149 config X86_REBOOTFIXUPS
1150 bool "Enable X86 board specific fixups for reboot"
1153 This enables chipset and/or board specific fixups to be done
1154 in order to get reboot to work correctly. This is only needed on
1155 some combinations of hardware and BIOS. The symptom, for which
1156 this config is intended, is when reboot ends with a stalled/hung
1159 Currently, the only fixup is for the Geode machines using
1160 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1162 Say Y if you want to enable the fixup. Currently, it's safe to
1163 enable this option even if you don't need it.
1167 bool "CPU microcode loading support"
1169 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1172 If you say Y here, you will be able to update the microcode on
1173 Intel and AMD processors. The Intel support is for the IA32 family,
1174 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1175 AMD support is for families 0x10 and later. You will obviously need
1176 the actual microcode binary data itself which is not shipped with
1179 The preferred method to load microcode from a detached initrd is described
1180 in Documentation/x86/early-microcode.txt. For that you need to enable
1181 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1182 initrd for microcode blobs.
1184 In addition, you can build-in the microcode into the kernel. For that you
1185 need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
1186 to the CONFIG_EXTRA_FIRMWARE config option.
1188 config MICROCODE_INTEL
1189 bool "Intel microcode loading support"
1190 depends on MICROCODE
1194 This options enables microcode patch loading support for Intel
1197 For the current Intel microcode data package go to
1198 <https://downloadcenter.intel.com> and search for
1199 'Linux Processor Microcode Data File'.
1201 config MICROCODE_AMD
1202 bool "AMD microcode loading support"
1203 depends on MICROCODE
1206 If you select this option, microcode patch loading support for AMD
1207 processors will be enabled.
1209 config MICROCODE_OLD_INTERFACE
1211 depends on MICROCODE
1214 tristate "/dev/cpu/*/msr - Model-specific register support"
1216 This device gives privileged processes access to the x86
1217 Model-Specific Registers (MSRs). It is a character device with
1218 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1219 MSR accesses are directed to a specific CPU on multi-processor
1223 tristate "/dev/cpu/*/cpuid - CPU information support"
1225 This device gives processes access to the x86 CPUID instruction to
1226 be executed on a specific processor. It is a character device
1227 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1231 prompt "High Memory Support"
1238 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1239 However, the address space of 32-bit x86 processors is only 4
1240 Gigabytes large. That means that, if you have a large amount of
1241 physical memory, not all of it can be "permanently mapped" by the
1242 kernel. The physical memory that's not permanently mapped is called
1245 If you are compiling a kernel which will never run on a machine with
1246 more than 1 Gigabyte total physical RAM, answer "off" here (default
1247 choice and suitable for most users). This will result in a "3GB/1GB"
1248 split: 3GB are mapped so that each process sees a 3GB virtual memory
1249 space and the remaining part of the 4GB virtual memory space is used
1250 by the kernel to permanently map as much physical memory as
1253 If the machine has between 1 and 4 Gigabytes physical RAM, then
1256 If more than 4 Gigabytes is used then answer "64GB" here. This
1257 selection turns Intel PAE (Physical Address Extension) mode on.
1258 PAE implements 3-level paging on IA32 processors. PAE is fully
1259 supported by Linux, PAE mode is implemented on all recent Intel
1260 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1261 then the kernel will not boot on CPUs that don't support PAE!
1263 The actual amount of total physical memory will either be
1264 auto detected or can be forced by using a kernel command line option
1265 such as "mem=256M". (Try "man bootparam" or see the documentation of
1266 your boot loader (lilo or loadlin) about how to pass options to the
1267 kernel at boot time.)
1269 If unsure, say "off".
1274 Select this if you have a 32-bit processor and between 1 and 4
1275 gigabytes of physical RAM.
1282 Select this if you have a 32-bit processor and more than 4
1283 gigabytes of physical RAM.
1288 prompt "Memory split" if EXPERT
1292 Select the desired split between kernel and user memory.
1294 If the address range available to the kernel is less than the
1295 physical memory installed, the remaining memory will be available
1296 as "high memory". Accessing high memory is a little more costly
1297 than low memory, as it needs to be mapped into the kernel first.
1298 Note that increasing the kernel address space limits the range
1299 available to user programs, making the address space there
1300 tighter. Selecting anything other than the default 3G/1G split
1301 will also likely make your kernel incompatible with binary-only
1304 If you are not absolutely sure what you are doing, leave this
1308 bool "3G/1G user/kernel split"
1309 config VMSPLIT_3G_OPT
1311 bool "3G/1G user/kernel split (for full 1G low memory)"
1313 bool "2G/2G user/kernel split"
1314 config VMSPLIT_2G_OPT
1316 bool "2G/2G user/kernel split (for full 2G low memory)"
1318 bool "1G/3G user/kernel split"
1323 default 0xB0000000 if VMSPLIT_3G_OPT
1324 default 0x80000000 if VMSPLIT_2G
1325 default 0x78000000 if VMSPLIT_2G_OPT
1326 default 0x40000000 if VMSPLIT_1G
1332 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1335 bool "PAE (Physical Address Extension) Support"
1336 depends on X86_32 && !HIGHMEM4G
1339 PAE is required for NX support, and furthermore enables
1340 larger swapspace support for non-overcommit purposes. It
1341 has the cost of more pagetable lookup overhead, and also
1342 consumes more pagetable space per process.
1344 config ARCH_PHYS_ADDR_T_64BIT
1346 depends on X86_64 || X86_PAE
1348 config ARCH_DMA_ADDR_T_64BIT
1350 depends on X86_64 || HIGHMEM64G
1352 config X86_DIRECT_GBPAGES
1354 depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1356 Certain kernel features effectively disable kernel
1357 linear 1 GB mappings (even if the CPU otherwise
1358 supports them), so don't confuse the user by printing
1359 that we have them enabled.
1361 # Common NUMA Features
1363 bool "Numa Memory Allocation and Scheduler Support"
1365 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1366 default y if X86_BIGSMP
1368 Enable NUMA (Non Uniform Memory Access) support.
1370 The kernel will try to allocate memory used by a CPU on the
1371 local memory controller of the CPU and add some more
1372 NUMA awareness to the kernel.
1374 For 64-bit this is recommended if the system is Intel Core i7
1375 (or later), AMD Opteron, or EM64T NUMA.
1377 For 32-bit this is only needed if you boot a 32-bit
1378 kernel on a 64-bit NUMA platform.
1380 Otherwise, you should say N.
1384 prompt "Old style AMD Opteron NUMA detection"
1385 depends on X86_64 && NUMA && PCI
1387 Enable AMD NUMA node topology detection. You should say Y here if
1388 you have a multi processor AMD system. This uses an old method to
1389 read the NUMA configuration directly from the builtin Northbridge
1390 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1391 which also takes priority if both are compiled in.
1393 config X86_64_ACPI_NUMA
1395 prompt "ACPI NUMA detection"
1396 depends on X86_64 && NUMA && ACPI && PCI
1399 Enable ACPI SRAT based node topology detection.
1401 # Some NUMA nodes have memory ranges that span
1402 # other nodes. Even though a pfn is valid and
1403 # between a node's start and end pfns, it may not
1404 # reside on that node. See memmap_init_zone()
1406 config NODES_SPAN_OTHER_NODES
1408 depends on X86_64_ACPI_NUMA
1411 bool "NUMA emulation"
1414 Enable NUMA emulation. A flat machine will be split
1415 into virtual nodes when booted with "numa=fake=N", where N is the
1416 number of nodes. This is only useful for debugging.
1419 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1421 default "10" if MAXSMP
1422 default "6" if X86_64
1424 depends on NEED_MULTIPLE_NODES
1426 Specify the maximum number of NUMA Nodes available on the target
1427 system. Increases memory reserved to accommodate various tables.
1429 config ARCH_HAVE_MEMORY_PRESENT
1431 depends on X86_32 && DISCONTIGMEM
1433 config NEED_NODE_MEMMAP_SIZE
1435 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1437 config ARCH_FLATMEM_ENABLE
1439 depends on X86_32 && !NUMA
1441 config ARCH_DISCONTIGMEM_ENABLE
1443 depends on NUMA && X86_32
1445 config ARCH_DISCONTIGMEM_DEFAULT
1447 depends on NUMA && X86_32
1449 config ARCH_SPARSEMEM_ENABLE
1451 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1452 select SPARSEMEM_STATIC if X86_32
1453 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1455 config ARCH_SPARSEMEM_DEFAULT
1459 config ARCH_SELECT_MEMORY_MODEL
1461 depends on ARCH_SPARSEMEM_ENABLE
1463 config ARCH_MEMORY_PROBE
1464 bool "Enable sysfs memory/probe interface"
1465 depends on X86_64 && MEMORY_HOTPLUG
1467 This option enables a sysfs memory/probe interface for testing.
1468 See Documentation/memory-hotplug.txt for more information.
1469 If you are unsure how to answer this question, answer N.
1471 config ARCH_PROC_KCORE_TEXT
1473 depends on X86_64 && PROC_KCORE
1475 config ILLEGAL_POINTER_VALUE
1478 default 0xdead000000000000 if X86_64
1482 config X86_PMEM_LEGACY_DEVICE
1485 config X86_PMEM_LEGACY
1486 tristate "Support non-standard NVDIMMs and ADR protected memory"
1487 depends on PHYS_ADDR_T_64BIT
1489 select X86_PMEM_LEGACY_DEVICE
1492 Treat memory marked using the non-standard e820 type of 12 as used
1493 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1494 The kernel will offer these regions to the 'pmem' driver so
1495 they can be used for persistent storage.
1500 bool "Allocate 3rd-level pagetables from highmem"
1503 The VM uses one page table entry for each page of physical memory.
1504 For systems with a lot of RAM, this can be wasteful of precious
1505 low memory. Setting this option will put user-space page table
1506 entries in high memory.
1508 config X86_CHECK_BIOS_CORRUPTION
1509 bool "Check for low memory corruption"
1511 Periodically check for memory corruption in low memory, which
1512 is suspected to be caused by BIOS. Even when enabled in the
1513 configuration, it is disabled at runtime. Enable it by
1514 setting "memory_corruption_check=1" on the kernel command
1515 line. By default it scans the low 64k of memory every 60
1516 seconds; see the memory_corruption_check_size and
1517 memory_corruption_check_period parameters in
1518 Documentation/kernel-parameters.txt to adjust this.
1520 When enabled with the default parameters, this option has
1521 almost no overhead, as it reserves a relatively small amount
1522 of memory and scans it infrequently. It both detects corruption
1523 and prevents it from affecting the running system.
1525 It is, however, intended as a diagnostic tool; if repeatable
1526 BIOS-originated corruption always affects the same memory,
1527 you can use memmap= to prevent the kernel from using that
1530 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1531 bool "Set the default setting of memory_corruption_check"
1532 depends on X86_CHECK_BIOS_CORRUPTION
1535 Set whether the default state of memory_corruption_check is
1538 config X86_RESERVE_LOW
1539 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1543 Specify the amount of low memory to reserve for the BIOS.
1545 The first page contains BIOS data structures that the kernel
1546 must not use, so that page must always be reserved.
1548 By default we reserve the first 64K of physical RAM, as a
1549 number of BIOSes are known to corrupt that memory range
1550 during events such as suspend/resume or monitor cable
1551 insertion, so it must not be used by the kernel.
1553 You can set this to 4 if you are absolutely sure that you
1554 trust the BIOS to get all its memory reservations and usages
1555 right. If you know your BIOS have problems beyond the
1556 default 64K area, you can set this to 640 to avoid using the
1557 entire low memory range.
1559 If you have doubts about the BIOS (e.g. suspend/resume does
1560 not work or there's kernel crashes after certain hardware
1561 hotplug events) then you might want to enable
1562 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1563 typical corruption patterns.
1565 Leave this to the default value of 64 if you are unsure.
1567 config MATH_EMULATION
1569 depends on MODIFY_LDT_SYSCALL
1570 prompt "Math emulation" if X86_32
1572 Linux can emulate a math coprocessor (used for floating point
1573 operations) if you don't have one. 486DX and Pentium processors have
1574 a math coprocessor built in, 486SX and 386 do not, unless you added
1575 a 487DX or 387, respectively. (The messages during boot time can
1576 give you some hints here ["man dmesg"].) Everyone needs either a
1577 coprocessor or this emulation.
1579 If you don't have a math coprocessor, you need to say Y here; if you
1580 say Y here even though you have a coprocessor, the coprocessor will
1581 be used nevertheless. (This behavior can be changed with the kernel
1582 command line option "no387", which comes handy if your coprocessor
1583 is broken. Try "man bootparam" or see the documentation of your boot
1584 loader (lilo or loadlin) about how to pass options to the kernel at
1585 boot time.) This means that it is a good idea to say Y here if you
1586 intend to use this kernel on different machines.
1588 More information about the internals of the Linux math coprocessor
1589 emulation can be found in <file:arch/x86/math-emu/README>.
1591 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1592 kernel, it won't hurt.
1596 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1598 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1599 the Memory Type Range Registers (MTRRs) may be used to control
1600 processor access to memory ranges. This is most useful if you have
1601 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1602 allows bus write transfers to be combined into a larger transfer
1603 before bursting over the PCI/AGP bus. This can increase performance
1604 of image write operations 2.5 times or more. Saying Y here creates a
1605 /proc/mtrr file which may be used to manipulate your processor's
1606 MTRRs. Typically the X server should use this.
1608 This code has a reasonably generic interface so that similar
1609 control registers on other processors can be easily supported
1612 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1613 Registers (ARRs) which provide a similar functionality to MTRRs. For
1614 these, the ARRs are used to emulate the MTRRs.
1615 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1616 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1617 write-combining. All of these processors are supported by this code
1618 and it makes sense to say Y here if you have one of them.
1620 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1621 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1622 can lead to all sorts of problems, so it's good to say Y here.
1624 You can safely say Y even if your machine doesn't have MTRRs, you'll
1625 just add about 9 KB to your kernel.
1627 See <file:Documentation/x86/mtrr.txt> for more information.
1629 config MTRR_SANITIZER
1631 prompt "MTRR cleanup support"
1634 Convert MTRR layout from continuous to discrete, so X drivers can
1635 add writeback entries.
1637 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1638 The largest mtrr entry size for a continuous block can be set with
1643 config MTRR_SANITIZER_ENABLE_DEFAULT
1644 int "MTRR cleanup enable value (0-1)"
1647 depends on MTRR_SANITIZER
1649 Enable mtrr cleanup default value
1651 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1652 int "MTRR cleanup spare reg num (0-7)"
1655 depends on MTRR_SANITIZER
1657 mtrr cleanup spare entries default, it can be changed via
1658 mtrr_spare_reg_nr=N on the kernel command line.
1662 prompt "x86 PAT support" if EXPERT
1665 Use PAT attributes to setup page level cache control.
1667 PATs are the modern equivalents of MTRRs and are much more
1668 flexible than MTRRs.
1670 Say N here if you see bootup problems (boot crash, boot hang,
1671 spontaneous reboots) or a non-working video driver.
1675 config ARCH_USES_PG_UNCACHED
1681 prompt "x86 architectural random number generator" if EXPERT
1683 Enable the x86 architectural RDRAND instruction
1684 (Intel Bull Mountain technology) to generate random numbers.
1685 If supported, this is a high bandwidth, cryptographically
1686 secure hardware random number generator.
1690 prompt "Supervisor Mode Access Prevention" if EXPERT
1692 Supervisor Mode Access Prevention (SMAP) is a security
1693 feature in newer Intel processors. There is a small
1694 performance cost if this enabled and turned on; there is
1695 also a small increase in the kernel size if this is enabled.
1699 config X86_INTEL_MPX
1700 prompt "Intel MPX (Memory Protection Extensions)"
1702 depends on CPU_SUP_INTEL
1704 MPX provides hardware features that can be used in
1705 conjunction with compiler-instrumented code to check
1706 memory references. It is designed to detect buffer
1707 overflow or underflow bugs.
1709 This option enables running applications which are
1710 instrumented or otherwise use MPX. It does not use MPX
1711 itself inside the kernel or to protect the kernel
1712 against bad memory references.
1714 Enabling this option will make the kernel larger:
1715 ~8k of kernel text and 36 bytes of data on a 64-bit
1716 defconfig. It adds a long to the 'mm_struct' which
1717 will increase the kernel memory overhead of each
1718 process and adds some branches to paths used during
1719 exec() and munmap().
1721 For details, see Documentation/x86/intel_mpx.txt
1725 config X86_INTEL_MEMORY_PROTECTION_KEYS
1726 prompt "Intel Memory Protection Keys"
1728 # Note: only available in 64-bit mode
1729 depends on CPU_SUP_INTEL && X86_64
1731 Memory Protection Keys provides a mechanism for enforcing
1732 page-based protections, but without requiring modification of the
1733 page tables when an application changes protection domains.
1735 For details, see Documentation/x86/protection-keys.txt
1740 bool "EFI runtime service support"
1743 select EFI_RUNTIME_WRAPPERS
1745 This enables the kernel to use EFI runtime services that are
1746 available (such as the EFI variable services).
1748 This option is only useful on systems that have EFI firmware.
1749 In addition, you should use the latest ELILO loader available
1750 at <http://elilo.sourceforge.net> in order to take advantage
1751 of EFI runtime services. However, even with this option, the
1752 resultant kernel should continue to boot on existing non-EFI
1756 bool "EFI stub support"
1757 depends on EFI && !X86_USE_3DNOW
1760 This kernel feature allows a bzImage to be loaded directly
1761 by EFI firmware without the use of a bootloader.
1763 See Documentation/efi-stub.txt for more information.
1766 bool "EFI mixed-mode support"
1767 depends on EFI_STUB && X86_64
1769 Enabling this feature allows a 64-bit kernel to be booted
1770 on a 32-bit firmware, provided that your CPU supports 64-bit
1773 Note that it is not possible to boot a mixed-mode enabled
1774 kernel via the EFI boot stub - a bootloader that supports
1775 the EFI handover protocol must be used.
1781 prompt "Enable seccomp to safely compute untrusted bytecode"
1783 This kernel feature is useful for number crunching applications
1784 that may need to compute untrusted bytecode during their
1785 execution. By using pipes or other transports made available to
1786 the process as file descriptors supporting the read/write
1787 syscalls, it's possible to isolate those applications in
1788 their own address space using seccomp. Once seccomp is
1789 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1790 and the task is only allowed to execute a few safe syscalls
1791 defined by each seccomp mode.
1793 If unsure, say Y. Only embedded should say N here.
1795 source kernel/Kconfig.hz
1798 bool "kexec system call"
1801 kexec is a system call that implements the ability to shutdown your
1802 current kernel, and to start another kernel. It is like a reboot
1803 but it is independent of the system firmware. And like a reboot
1804 you can start any kernel with it, not just Linux.
1806 The name comes from the similarity to the exec system call.
1808 It is an ongoing process to be certain the hardware in a machine
1809 is properly shutdown, so do not be surprised if this code does not
1810 initially work for you. As of this writing the exact hardware
1811 interface is strongly in flux, so no good recommendation can be
1815 bool "kexec file based system call"
1820 depends on CRYPTO_SHA256=y
1822 This is new version of kexec system call. This system call is
1823 file based and takes file descriptors as system call argument
1824 for kernel and initramfs as opposed to list of segments as
1825 accepted by previous system call.
1827 config KEXEC_VERIFY_SIG
1828 bool "Verify kernel signature during kexec_file_load() syscall"
1829 depends on KEXEC_FILE
1831 This option makes kernel signature verification mandatory for
1832 the kexec_file_load() syscall.
1834 In addition to that option, you need to enable signature
1835 verification for the corresponding kernel image type being
1836 loaded in order for this to work.
1838 config KEXEC_BZIMAGE_VERIFY_SIG
1839 bool "Enable bzImage signature verification support"
1840 depends on KEXEC_VERIFY_SIG
1841 depends on SIGNED_PE_FILE_VERIFICATION
1842 select SYSTEM_TRUSTED_KEYRING
1844 Enable bzImage signature verification support.
1847 bool "kernel crash dumps"
1848 depends on X86_64 || (X86_32 && HIGHMEM)
1850 Generate crash dump after being started by kexec.
1851 This should be normally only set in special crash dump kernels
1852 which are loaded in the main kernel with kexec-tools into
1853 a specially reserved region and then later executed after
1854 a crash by kdump/kexec. The crash dump kernel must be compiled
1855 to a memory address not used by the main kernel or BIOS using
1856 PHYSICAL_START, or it must be built as a relocatable image
1857 (CONFIG_RELOCATABLE=y).
1858 For more details see Documentation/kdump/kdump.txt
1862 depends on KEXEC && HIBERNATION
1864 Jump between original kernel and kexeced kernel and invoke
1865 code in physical address mode via KEXEC
1867 config PHYSICAL_START
1868 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1871 This gives the physical address where the kernel is loaded.
1873 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1874 bzImage will decompress itself to above physical address and
1875 run from there. Otherwise, bzImage will run from the address where
1876 it has been loaded by the boot loader and will ignore above physical
1879 In normal kdump cases one does not have to set/change this option
1880 as now bzImage can be compiled as a completely relocatable image
1881 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1882 address. This option is mainly useful for the folks who don't want
1883 to use a bzImage for capturing the crash dump and want to use a
1884 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1885 to be specifically compiled to run from a specific memory area
1886 (normally a reserved region) and this option comes handy.
1888 So if you are using bzImage for capturing the crash dump,
1889 leave the value here unchanged to 0x1000000 and set
1890 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1891 for capturing the crash dump change this value to start of
1892 the reserved region. In other words, it can be set based on
1893 the "X" value as specified in the "crashkernel=YM@XM"
1894 command line boot parameter passed to the panic-ed
1895 kernel. Please take a look at Documentation/kdump/kdump.txt
1896 for more details about crash dumps.
1898 Usage of bzImage for capturing the crash dump is recommended as
1899 one does not have to build two kernels. Same kernel can be used
1900 as production kernel and capture kernel. Above option should have
1901 gone away after relocatable bzImage support is introduced. But it
1902 is present because there are users out there who continue to use
1903 vmlinux for dump capture. This option should go away down the
1906 Don't change this unless you know what you are doing.
1909 bool "Build a relocatable kernel"
1912 This builds a kernel image that retains relocation information
1913 so it can be loaded someplace besides the default 1MB.
1914 The relocations tend to make the kernel binary about 10% larger,
1915 but are discarded at runtime.
1917 One use is for the kexec on panic case where the recovery kernel
1918 must live at a different physical address than the primary
1921 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1922 it has been loaded at and the compile time physical address
1923 (CONFIG_PHYSICAL_START) is used as the minimum location.
1925 config RANDOMIZE_BASE
1926 bool "Randomize the address of the kernel image (KASLR)"
1927 depends on RELOCATABLE
1930 In support of Kernel Address Space Layout Randomization (KASLR),
1931 this randomizes the physical address at which the kernel image
1932 is decompressed and the virtual address where the kernel
1933 image is mapped, as a security feature that deters exploit
1934 attempts relying on knowledge of the location of kernel
1937 On 64-bit, the kernel physical and virtual addresses are
1938 randomized separately. The physical address will be anywhere
1939 between 16MB and the top of physical memory (up to 64TB). The
1940 virtual address will be randomized from 16MB up to 1GB (9 bits
1941 of entropy). Note that this also reduces the memory space
1942 available to kernel modules from 1.5GB to 1GB.
1944 On 32-bit, the kernel physical and virtual addresses are
1945 randomized together. They will be randomized from 16MB up to
1946 512MB (8 bits of entropy).
1948 Entropy is generated using the RDRAND instruction if it is
1949 supported. If RDTSC is supported, its value is mixed into
1950 the entropy pool as well. If neither RDRAND nor RDTSC are
1951 supported, then entropy is read from the i8254 timer. The
1952 usable entropy is limited by the kernel being built using
1953 2GB addressing, and that PHYSICAL_ALIGN must be at a
1954 minimum of 2MB. As a result, only 10 bits of entropy are
1955 theoretically possible, but the implementations are further
1956 limited due to memory layouts.
1958 If CONFIG_HIBERNATE is also enabled, KASLR is disabled at boot
1959 time. To enable it, boot with "kaslr" on the kernel command
1960 line (which will also disable hibernation).
1964 # Relocation on x86 needs some additional build support
1965 config X86_NEED_RELOCS
1967 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1969 config PHYSICAL_ALIGN
1970 hex "Alignment value to which kernel should be aligned"
1972 range 0x2000 0x1000000 if X86_32
1973 range 0x200000 0x1000000 if X86_64
1975 This value puts the alignment restrictions on physical address
1976 where kernel is loaded and run from. Kernel is compiled for an
1977 address which meets above alignment restriction.
1979 If bootloader loads the kernel at a non-aligned address and
1980 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1981 address aligned to above value and run from there.
1983 If bootloader loads the kernel at a non-aligned address and
1984 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1985 load address and decompress itself to the address it has been
1986 compiled for and run from there. The address for which kernel is
1987 compiled already meets above alignment restrictions. Hence the
1988 end result is that kernel runs from a physical address meeting
1989 above alignment restrictions.
1991 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1992 this value must be a multiple of 0x200000.
1994 Don't change this unless you know what you are doing.
1997 bool "Support for hot-pluggable CPUs"
2000 Say Y here to allow turning CPUs off and on. CPUs can be
2001 controlled through /sys/devices/system/cpu.
2002 ( Note: power management support will enable this option
2003 automatically on SMP systems. )
2004 Say N if you want to disable CPU hotplug.
2006 config BOOTPARAM_HOTPLUG_CPU0
2007 bool "Set default setting of cpu0_hotpluggable"
2009 depends on HOTPLUG_CPU
2011 Set whether default state of cpu0_hotpluggable is on or off.
2013 Say Y here to enable CPU0 hotplug by default. If this switch
2014 is turned on, there is no need to give cpu0_hotplug kernel
2015 parameter and the CPU0 hotplug feature is enabled by default.
2017 Please note: there are two known CPU0 dependencies if you want
2018 to enable the CPU0 hotplug feature either by this switch or by
2019 cpu0_hotplug kernel parameter.
2021 First, resume from hibernate or suspend always starts from CPU0.
2022 So hibernate and suspend are prevented if CPU0 is offline.
2024 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2025 offline if any interrupt can not migrate out of CPU0. There may
2026 be other CPU0 dependencies.
2028 Please make sure the dependencies are under your control before
2029 you enable this feature.
2031 Say N if you don't want to enable CPU0 hotplug feature by default.
2032 You still can enable the CPU0 hotplug feature at boot by kernel
2033 parameter cpu0_hotplug.
2035 config DEBUG_HOTPLUG_CPU0
2037 prompt "Debug CPU0 hotplug"
2038 depends on HOTPLUG_CPU
2040 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2041 soon as possible and boots up userspace with CPU0 offlined. User
2042 can online CPU0 back after boot time.
2044 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2045 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2046 compilation or giving cpu0_hotplug kernel parameter at boot.
2052 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2053 depends on X86_32 || IA32_EMULATION
2055 Certain buggy versions of glibc will crash if they are
2056 presented with a 32-bit vDSO that is not mapped at the address
2057 indicated in its segment table.
2059 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2060 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2061 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2062 the only released version with the bug, but OpenSUSE 9
2063 contains a buggy "glibc 2.3.2".
2065 The symptom of the bug is that everything crashes on startup, saying:
2066 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2068 Saying Y here changes the default value of the vdso32 boot
2069 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2070 This works around the glibc bug but hurts performance.
2072 If unsure, say N: if you are compiling your own kernel, you
2073 are unlikely to be using a buggy version of glibc.
2076 prompt "vsyscall table for legacy applications"
2078 default LEGACY_VSYSCALL_EMULATE
2080 Legacy user code that does not know how to find the vDSO expects
2081 to be able to issue three syscalls by calling fixed addresses in
2082 kernel space. Since this location is not randomized with ASLR,
2083 it can be used to assist security vulnerability exploitation.
2085 This setting can be changed at boot time via the kernel command
2086 line parameter vsyscall=[native|emulate|none].
2088 On a system with recent enough glibc (2.14 or newer) and no
2089 static binaries, you can say None without a performance penalty
2090 to improve security.
2092 If unsure, select "Emulate".
2094 config LEGACY_VSYSCALL_NATIVE
2097 Actual executable code is located in the fixed vsyscall
2098 address mapping, implementing time() efficiently. Since
2099 this makes the mapping executable, it can be used during
2100 security vulnerability exploitation (traditionally as
2101 ROP gadgets). This configuration is not recommended.
2103 config LEGACY_VSYSCALL_EMULATE
2106 The kernel traps and emulates calls into the fixed
2107 vsyscall address mapping. This makes the mapping
2108 non-executable, but it still contains known contents,
2109 which could be used in certain rare security vulnerability
2110 exploits. This configuration is recommended when userspace
2111 still uses the vsyscall area.
2113 config LEGACY_VSYSCALL_NONE
2116 There will be no vsyscall mapping at all. This will
2117 eliminate any risk of ASLR bypass due to the vsyscall
2118 fixed address mapping. Attempts to use the vsyscalls
2119 will be reported to dmesg, so that either old or
2120 malicious userspace programs can be identified.
2125 bool "Built-in kernel command line"
2127 Allow for specifying boot arguments to the kernel at
2128 build time. On some systems (e.g. embedded ones), it is
2129 necessary or convenient to provide some or all of the
2130 kernel boot arguments with the kernel itself (that is,
2131 to not rely on the boot loader to provide them.)
2133 To compile command line arguments into the kernel,
2134 set this option to 'Y', then fill in the
2135 boot arguments in CONFIG_CMDLINE.
2137 Systems with fully functional boot loaders (i.e. non-embedded)
2138 should leave this option set to 'N'.
2141 string "Built-in kernel command string"
2142 depends on CMDLINE_BOOL
2145 Enter arguments here that should be compiled into the kernel
2146 image and used at boot time. If the boot loader provides a
2147 command line at boot time, it is appended to this string to
2148 form the full kernel command line, when the system boots.
2150 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2151 change this behavior.
2153 In most cases, the command line (whether built-in or provided
2154 by the boot loader) should specify the device for the root
2157 config CMDLINE_OVERRIDE
2158 bool "Built-in command line overrides boot loader arguments"
2159 depends on CMDLINE_BOOL
2161 Set this option to 'Y' to have the kernel ignore the boot loader
2162 command line, and use ONLY the built-in command line.
2164 This is used to work around broken boot loaders. This should
2165 be set to 'N' under normal conditions.
2167 config MODIFY_LDT_SYSCALL
2168 bool "Enable the LDT (local descriptor table)" if EXPERT
2171 Linux can allow user programs to install a per-process x86
2172 Local Descriptor Table (LDT) using the modify_ldt(2) system
2173 call. This is required to run 16-bit or segmented code such as
2174 DOSEMU or some Wine programs. It is also used by some very old
2175 threading libraries.
2177 Enabling this feature adds a small amount of overhead to
2178 context switches and increases the low-level kernel attack
2179 surface. Disabling it removes the modify_ldt(2) system call.
2181 Saying 'N' here may make sense for embedded or server kernels.
2183 source "kernel/livepatch/Kconfig"
2187 config ARCH_ENABLE_MEMORY_HOTPLUG
2189 depends on X86_64 || (X86_32 && HIGHMEM)
2191 config ARCH_ENABLE_MEMORY_HOTREMOVE
2193 depends on MEMORY_HOTPLUG
2195 config USE_PERCPU_NUMA_NODE_ID
2199 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2201 depends on X86_64 || X86_PAE
2203 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2205 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2207 menu "Power management and ACPI options"
2209 config ARCH_HIBERNATION_HEADER
2211 depends on X86_64 && HIBERNATION
2213 source "kernel/power/Kconfig"
2215 source "drivers/acpi/Kconfig"
2217 source "drivers/sfi/Kconfig"
2224 tristate "APM (Advanced Power Management) BIOS support"
2225 depends on X86_32 && PM_SLEEP
2227 APM is a BIOS specification for saving power using several different
2228 techniques. This is mostly useful for battery powered laptops with
2229 APM compliant BIOSes. If you say Y here, the system time will be
2230 reset after a RESUME operation, the /proc/apm device will provide
2231 battery status information, and user-space programs will receive
2232 notification of APM "events" (e.g. battery status change).
2234 If you select "Y" here, you can disable actual use of the APM
2235 BIOS by passing the "apm=off" option to the kernel at boot time.
2237 Note that the APM support is almost completely disabled for
2238 machines with more than one CPU.
2240 In order to use APM, you will need supporting software. For location
2241 and more information, read <file:Documentation/power/apm-acpi.txt>
2242 and the Battery Powered Linux mini-HOWTO, available from
2243 <http://www.tldp.org/docs.html#howto>.
2245 This driver does not spin down disk drives (see the hdparm(8)
2246 manpage ("man 8 hdparm") for that), and it doesn't turn off
2247 VESA-compliant "green" monitors.
2249 This driver does not support the TI 4000M TravelMate and the ACER
2250 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2251 desktop machines also don't have compliant BIOSes, and this driver
2252 may cause those machines to panic during the boot phase.
2254 Generally, if you don't have a battery in your machine, there isn't
2255 much point in using this driver and you should say N. If you get
2256 random kernel OOPSes or reboots that don't seem to be related to
2257 anything, try disabling/enabling this option (or disabling/enabling
2260 Some other things you should try when experiencing seemingly random,
2263 1) make sure that you have enough swap space and that it is
2265 2) pass the "no-hlt" option to the kernel
2266 3) switch on floating point emulation in the kernel and pass
2267 the "no387" option to the kernel
2268 4) pass the "floppy=nodma" option to the kernel
2269 5) pass the "mem=4M" option to the kernel (thereby disabling
2270 all but the first 4 MB of RAM)
2271 6) make sure that the CPU is not over clocked.
2272 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2273 8) disable the cache from your BIOS settings
2274 9) install a fan for the video card or exchange video RAM
2275 10) install a better fan for the CPU
2276 11) exchange RAM chips
2277 12) exchange the motherboard.
2279 To compile this driver as a module, choose M here: the
2280 module will be called apm.
2284 config APM_IGNORE_USER_SUSPEND
2285 bool "Ignore USER SUSPEND"
2287 This option will ignore USER SUSPEND requests. On machines with a
2288 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2289 series notebooks, it is necessary to say Y because of a BIOS bug.
2291 config APM_DO_ENABLE
2292 bool "Enable PM at boot time"
2294 Enable APM features at boot time. From page 36 of the APM BIOS
2295 specification: "When disabled, the APM BIOS does not automatically
2296 power manage devices, enter the Standby State, enter the Suspend
2297 State, or take power saving steps in response to CPU Idle calls."
2298 This driver will make CPU Idle calls when Linux is idle (unless this
2299 feature is turned off -- see "Do CPU IDLE calls", below). This
2300 should always save battery power, but more complicated APM features
2301 will be dependent on your BIOS implementation. You may need to turn
2302 this option off if your computer hangs at boot time when using APM
2303 support, or if it beeps continuously instead of suspending. Turn
2304 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2305 T400CDT. This is off by default since most machines do fine without
2310 bool "Make CPU Idle calls when idle"
2312 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2313 On some machines, this can activate improved power savings, such as
2314 a slowed CPU clock rate, when the machine is idle. These idle calls
2315 are made after the idle loop has run for some length of time (e.g.,
2316 333 mS). On some machines, this will cause a hang at boot time or
2317 whenever the CPU becomes idle. (On machines with more than one CPU,
2318 this option does nothing.)
2320 config APM_DISPLAY_BLANK
2321 bool "Enable console blanking using APM"
2323 Enable console blanking using the APM. Some laptops can use this to
2324 turn off the LCD backlight when the screen blanker of the Linux
2325 virtual console blanks the screen. Note that this is only used by
2326 the virtual console screen blanker, and won't turn off the backlight
2327 when using the X Window system. This also doesn't have anything to
2328 do with your VESA-compliant power-saving monitor. Further, this
2329 option doesn't work for all laptops -- it might not turn off your
2330 backlight at all, or it might print a lot of errors to the console,
2331 especially if you are using gpm.
2333 config APM_ALLOW_INTS
2334 bool "Allow interrupts during APM BIOS calls"
2336 Normally we disable external interrupts while we are making calls to
2337 the APM BIOS as a measure to lessen the effects of a badly behaving
2338 BIOS implementation. The BIOS should reenable interrupts if it
2339 needs to. Unfortunately, some BIOSes do not -- especially those in
2340 many of the newer IBM Thinkpads. If you experience hangs when you
2341 suspend, try setting this to Y. Otherwise, say N.
2345 source "drivers/cpufreq/Kconfig"
2347 source "drivers/cpuidle/Kconfig"
2349 source "drivers/idle/Kconfig"
2354 menu "Bus options (PCI etc.)"
2360 Find out whether you have a PCI motherboard. PCI is the name of a
2361 bus system, i.e. the way the CPU talks to the other stuff inside
2362 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2363 VESA. If you have PCI, say Y, otherwise N.
2366 prompt "PCI access mode"
2367 depends on X86_32 && PCI
2370 On PCI systems, the BIOS can be used to detect the PCI devices and
2371 determine their configuration. However, some old PCI motherboards
2372 have BIOS bugs and may crash if this is done. Also, some embedded
2373 PCI-based systems don't have any BIOS at all. Linux can also try to
2374 detect the PCI hardware directly without using the BIOS.
2376 With this option, you can specify how Linux should detect the
2377 PCI devices. If you choose "BIOS", the BIOS will be used,
2378 if you choose "Direct", the BIOS won't be used, and if you
2379 choose "MMConfig", then PCI Express MMCONFIG will be used.
2380 If you choose "Any", the kernel will try MMCONFIG, then the
2381 direct access method and falls back to the BIOS if that doesn't
2382 work. If unsure, go with the default, which is "Any".
2387 config PCI_GOMMCONFIG
2404 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2406 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2409 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2413 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2417 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2421 depends on PCI && XEN
2429 bool "Support mmconfig PCI config space access"
2430 depends on X86_64 && PCI && ACPI
2432 config PCI_CNB20LE_QUIRK
2433 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2436 Read the PCI windows out of the CNB20LE host bridge. This allows
2437 PCI hotplug to work on systems with the CNB20LE chipset which do
2440 There's no public spec for this chipset, and this functionality
2441 is known to be incomplete.
2443 You should say N unless you know you need this.
2445 source "drivers/pci/Kconfig"
2448 bool "ISA-style bus support on modern systems" if EXPERT
2451 Enables ISA-style drivers on modern systems. This is necessary to
2452 support PC/104 devices on X86_64 platforms.
2456 # x86_64 have no ISA slots, but can have ISA-style DMA.
2458 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2461 Enables ISA-style DMA support for devices requiring such controllers.
2469 Find out whether you have ISA slots on your motherboard. ISA is the
2470 name of a bus system, i.e. the way the CPU talks to the other stuff
2471 inside your box. Other bus systems are PCI, EISA, MicroChannel
2472 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2473 newer boards don't support it. If you have ISA, say Y, otherwise N.
2479 The Extended Industry Standard Architecture (EISA) bus was
2480 developed as an open alternative to the IBM MicroChannel bus.
2482 The EISA bus provided some of the features of the IBM MicroChannel
2483 bus while maintaining backward compatibility with cards made for
2484 the older ISA bus. The EISA bus saw limited use between 1988 and
2485 1995 when it was made obsolete by the PCI bus.
2487 Say Y here if you are building a kernel for an EISA-based machine.
2491 source "drivers/eisa/Kconfig"
2494 tristate "NatSemi SCx200 support"
2496 This provides basic support for National Semiconductor's
2497 (now AMD's) Geode processors. The driver probes for the
2498 PCI-IDs of several on-chip devices, so its a good dependency
2499 for other scx200_* drivers.
2501 If compiled as a module, the driver is named scx200.
2503 config SCx200HR_TIMER
2504 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2508 This driver provides a clocksource built upon the on-chip
2509 27MHz high-resolution timer. Its also a workaround for
2510 NSC Geode SC-1100's buggy TSC, which loses time when the
2511 processor goes idle (as is done by the scheduler). The
2512 other workaround is idle=poll boot option.
2515 bool "One Laptop Per Child support"
2522 Add support for detecting the unique features of the OLPC
2526 bool "OLPC XO-1 Power Management"
2527 depends on OLPC && MFD_CS5535 && PM_SLEEP
2530 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2533 bool "OLPC XO-1 Real Time Clock"
2534 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2536 Add support for the XO-1 real time clock, which can be used as a
2537 programmable wakeup source.
2540 bool "OLPC XO-1 SCI extras"
2541 depends on OLPC && OLPC_XO1_PM
2547 Add support for SCI-based features of the OLPC XO-1 laptop:
2548 - EC-driven system wakeups
2552 - AC adapter status updates
2553 - Battery status updates
2555 config OLPC_XO15_SCI
2556 bool "OLPC XO-1.5 SCI extras"
2557 depends on OLPC && ACPI
2560 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2561 - EC-driven system wakeups
2562 - AC adapter status updates
2563 - Battery status updates
2566 bool "PCEngines ALIX System Support (LED setup)"
2569 This option enables system support for the PCEngines ALIX.
2570 At present this just sets up LEDs for GPIO control on
2571 ALIX2/3/6 boards. However, other system specific setup should
2574 Note: You must still enable the drivers for GPIO and LED support
2575 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2577 Note: You have to set alix.force=1 for boards with Award BIOS.
2580 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2583 This option enables system support for the Soekris Engineering net5501.
2586 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2590 This option enables system support for the Traverse Technologies GEOS.
2593 bool "Technologic Systems TS-5500 platform support"
2595 select CHECK_SIGNATURE
2599 This option enables system support for the Technologic Systems TS-5500.
2605 depends on CPU_SUP_AMD && PCI
2607 source "drivers/pcmcia/Kconfig"
2610 tristate "RapidIO support"
2614 If enabled this option will include drivers and the core
2615 infrastructure code to support RapidIO interconnect devices.
2617 source "drivers/rapidio/Kconfig"
2620 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2622 Firmwares often provide initial graphics framebuffers so the BIOS,
2623 bootloader or kernel can show basic video-output during boot for
2624 user-guidance and debugging. Historically, x86 used the VESA BIOS
2625 Extensions and EFI-framebuffers for this, which are mostly limited
2627 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2628 framebuffers so the new generic system-framebuffer drivers can be
2629 used on x86. If the framebuffer is not compatible with the generic
2630 modes, it is adverticed as fallback platform framebuffer so legacy
2631 drivers like efifb, vesafb and uvesafb can pick it up.
2632 If this option is not selected, all system framebuffers are always
2633 marked as fallback platform framebuffers as usual.
2635 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2636 not be able to pick up generic system framebuffers if this option
2637 is selected. You are highly encouraged to enable simplefb as
2638 replacement if you select this option. simplefb can correctly deal
2639 with generic system framebuffers. But you should still keep vesafb
2640 and others enabled as fallback if a system framebuffer is
2641 incompatible with simplefb.
2648 menu "Executable file formats / Emulations"
2650 source "fs/Kconfig.binfmt"
2652 config IA32_EMULATION
2653 bool "IA32 Emulation"
2656 select COMPAT_BINFMT_ELF
2657 select ARCH_WANT_OLD_COMPAT_IPC
2659 Include code to run legacy 32-bit programs under a
2660 64-bit kernel. You should likely turn this on, unless you're
2661 100% sure that you don't have any 32-bit programs left.
2664 tristate "IA32 a.out support"
2665 depends on IA32_EMULATION
2667 Support old a.out binaries in the 32bit emulation.
2670 bool "x32 ABI for 64-bit mode"
2673 Include code to run binaries for the x32 native 32-bit ABI
2674 for 64-bit processors. An x32 process gets access to the
2675 full 64-bit register file and wide data path while leaving
2676 pointers at 32 bits for smaller memory footprint.
2678 You will need a recent binutils (2.22 or later) with
2679 elf32_x86_64 support enabled to compile a kernel with this
2684 depends on IA32_EMULATION || X86_X32
2687 config COMPAT_FOR_U64_ALIGNMENT
2690 config SYSVIPC_COMPAT
2702 config HAVE_ATOMIC_IOMAP
2706 config X86_DEV_DMA_OPS
2708 depends on X86_64 || STA2X11
2710 config X86_DMA_REMAP
2720 tristate "Volume Management Device Driver"
2723 Adds support for the Intel Volume Management Device (VMD). VMD is a
2724 secondary PCI host bridge that allows PCI Express root ports,
2725 and devices attached to them, to be removed from the default
2726 PCI domain and placed within the VMD domain. This provides
2727 more bus resources than are otherwise possible with a
2728 single domain. If you know your system provides one of these and
2729 has devices attached to it, say Y; if you are not sure, say N.
2731 source "net/Kconfig"
2733 source "drivers/Kconfig"
2735 source "drivers/firmware/Kconfig"
2739 source "arch/x86/Kconfig.debug"
2741 source "security/Kconfig"
2743 source "crypto/Kconfig"
2745 source "arch/x86/kvm/Kconfig"
2747 source "lib/Kconfig"
projects / cascardo / linux.git / blob