3 bool "64-bit kernel" if ARCH = "x86"
6 Say yes to build a 64-bit kernel - formerly known as x86_64
7 Say no to build a 32-bit kernel - formerly known as i386
20 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
21 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
23 select ARCH_CLOCKSOURCE_DATA
24 select ARCH_DISCARD_MEMBLOCK
25 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
26 select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
27 select ARCH_HAS_ELF_RANDOMIZE
28 select ARCH_HAS_FAST_MULTIPLIER
29 select ARCH_HAS_GCOV_PROFILE_ALL
30 select ARCH_HAS_PMEM_API if X86_64
31 select ARCH_HAS_MMIO_FLUSH
32 select ARCH_HAS_SG_CHAIN
33 select ARCH_HAVE_NMI_SAFE_CMPXCHG
34 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
35 select ARCH_MIGHT_HAVE_PC_PARPORT
36 select ARCH_MIGHT_HAVE_PC_SERIO
37 select ARCH_SUPPORTS_ATOMIC_RMW
38 select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
39 select ARCH_SUPPORTS_INT128 if X86_64
40 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
41 select ARCH_USE_BUILTIN_BSWAP
42 select ARCH_USE_CMPXCHG_LOCKREF if X86_64
43 select ARCH_USE_QUEUED_RWLOCKS
44 select ARCH_USE_QUEUED_SPINLOCKS
45 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if SMP
46 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
47 select ARCH_WANT_FRAME_POINTERS
48 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
49 select ARCH_WANT_OPTIONAL_GPIOLIB
50 select BUILDTIME_EXTABLE_SORT
52 select CLKSRC_I8253 if X86_32
53 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
54 select CLOCKSOURCE_WATCHDOG
55 select CLONE_BACKWARDS if X86_32
56 select COMPAT_OLD_SIGACTION if IA32_EMULATION
57 select DCACHE_WORD_ACCESS
58 select EDAC_ATOMIC_SCRUB
60 select GENERIC_CLOCKEVENTS
61 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
62 select GENERIC_CLOCKEVENTS_MIN_ADJUST
63 select GENERIC_CMOS_UPDATE
64 select GENERIC_CPU_AUTOPROBE
65 select GENERIC_EARLY_IOREMAP
66 select GENERIC_FIND_FIRST_BIT
68 select GENERIC_IRQ_PROBE
69 select GENERIC_IRQ_SHOW
70 select GENERIC_PENDING_IRQ if SMP
71 select GENERIC_SMP_IDLE_THREAD
72 select GENERIC_STRNCPY_FROM_USER
73 select GENERIC_STRNLEN_USER
74 select GENERIC_TIME_VSYSCALL
75 select HAVE_ACPI_APEI if ACPI
76 select HAVE_ACPI_APEI_NMI if ACPI
77 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
78 select HAVE_AOUT if X86_32
79 select HAVE_ARCH_AUDITSYSCALL
80 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
81 select HAVE_ARCH_JUMP_LABEL
82 select HAVE_ARCH_KASAN if X86_64 && SPARSEMEM_VMEMMAP
84 select HAVE_ARCH_KMEMCHECK
85 select HAVE_ARCH_SECCOMP_FILTER
86 select HAVE_ARCH_SOFT_DIRTY if X86_64
87 select HAVE_ARCH_TRACEHOOK
88 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
89 select HAVE_BPF_JIT if X86_64
90 select HAVE_CC_STACKPROTECTOR
91 select HAVE_CMPXCHG_DOUBLE
92 select HAVE_CMPXCHG_LOCAL
93 select HAVE_CONTEXT_TRACKING if X86_64
94 select HAVE_COPY_THREAD_TLS
95 select HAVE_C_RECORDMCOUNT
96 select HAVE_DEBUG_KMEMLEAK
97 select HAVE_DEBUG_STACKOVERFLOW
98 select HAVE_DMA_API_DEBUG
100 select HAVE_DMA_CONTIGUOUS
101 select HAVE_DYNAMIC_FTRACE
102 select HAVE_DYNAMIC_FTRACE_WITH_REGS
103 select HAVE_EFFICIENT_UNALIGNED_ACCESS
104 select HAVE_FENTRY if X86_64
105 select HAVE_FTRACE_MCOUNT_RECORD
106 select HAVE_FUNCTION_GRAPH_FP_TEST
107 select HAVE_FUNCTION_GRAPH_TRACER
108 select HAVE_FUNCTION_TRACER
109 select HAVE_GENERIC_DMA_COHERENT if X86_32
110 select HAVE_HW_BREAKPOINT
112 select HAVE_IOREMAP_PROT
113 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
114 select HAVE_IRQ_TIME_ACCOUNTING
115 select HAVE_KERNEL_BZIP2
116 select HAVE_KERNEL_GZIP
117 select HAVE_KERNEL_LZ4
118 select HAVE_KERNEL_LZMA
119 select HAVE_KERNEL_LZO
120 select HAVE_KERNEL_XZ
122 select HAVE_KPROBES_ON_FTRACE
123 select HAVE_KRETPROBES
125 select HAVE_LIVEPATCH if X86_64
127 select HAVE_MEMBLOCK_NODE_MAP
128 select HAVE_MIXED_BREAKPOINTS_REGS
130 select HAVE_OPTPROBES
131 select HAVE_PCSPKR_PLATFORM
132 select HAVE_PERF_EVENTS
133 select HAVE_PERF_EVENTS_NMI
134 select HAVE_PERF_REGS
135 select HAVE_PERF_USER_STACK_DUMP
136 select HAVE_REGS_AND_STACK_ACCESS_API
137 select HAVE_SYSCALL_TRACEPOINTS
138 select HAVE_UID16 if X86_32 || IA32_EMULATION
139 select HAVE_UNSTABLE_SCHED_CLOCK
140 select HAVE_USER_RETURN_NOTIFIER
141 select IRQ_FORCED_THREADING
142 select MODULES_USE_ELF_RELA if X86_64
143 select MODULES_USE_ELF_REL if X86_32
144 select OLD_SIGACTION if X86_32
145 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
150 select SYSCTL_EXCEPTION_TRACE
151 select USER_STACKTRACE_SUPPORT
153 select X86_DEV_DMA_OPS if X86_64
154 select X86_FEATURE_NAMES if PROC_FS
156 config INSTRUCTION_DECODER
158 depends on KPROBES || PERF_EVENTS || UPROBES
160 config PERF_EVENTS_INTEL_UNCORE
162 depends on PERF_EVENTS && CPU_SUP_INTEL && PCI
166 default "elf32-i386" if X86_32
167 default "elf64-x86-64" if X86_64
169 config ARCH_DEFCONFIG
171 default "arch/x86/configs/i386_defconfig" if X86_32
172 default "arch/x86/configs/x86_64_defconfig" if X86_64
174 config LOCKDEP_SUPPORT
177 config STACKTRACE_SUPPORT
180 config HAVE_LATENCYTOP_SUPPORT
189 config NEED_DMA_MAP_STATE
191 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
193 config NEED_SG_DMA_LENGTH
196 config GENERIC_ISA_DMA
198 depends on ISA_DMA_API
203 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
205 config GENERIC_BUG_RELATIVE_POINTERS
208 config GENERIC_HWEIGHT
211 config ARCH_MAY_HAVE_PC_FDC
213 depends on ISA_DMA_API
215 config RWSEM_XCHGADD_ALGORITHM
218 config GENERIC_CALIBRATE_DELAY
221 config ARCH_HAS_CPU_RELAX
224 config ARCH_HAS_CACHE_LINE_SIZE
227 config HAVE_SETUP_PER_CPU_AREA
230 config NEED_PER_CPU_EMBED_FIRST_CHUNK
233 config NEED_PER_CPU_PAGE_FIRST_CHUNK
236 config ARCH_HIBERNATION_POSSIBLE
239 config ARCH_SUSPEND_POSSIBLE
242 config ARCH_WANT_HUGE_PMD_SHARE
245 config ARCH_WANT_GENERAL_HUGETLB
254 config ARCH_SUPPORTS_OPTIMIZED_INLINING
257 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
260 config KASAN_SHADOW_OFFSET
263 default 0xdffffc0000000000
265 config HAVE_INTEL_TXT
267 depends on INTEL_IOMMU && ACPI
271 depends on X86_32 && SMP
275 depends on X86_64 && SMP
277 config X86_32_LAZY_GS
279 depends on X86_32 && !CC_STACKPROTECTOR
281 config ARCH_HWEIGHT_CFLAGS
283 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
284 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
286 config ARCH_SUPPORTS_UPROBES
289 config FIX_EARLYCON_MEM
292 config PGTABLE_LEVELS
298 source "init/Kconfig"
299 source "kernel/Kconfig.freezer"
301 menu "Processor type and features"
304 bool "DMA memory allocation support" if EXPERT
307 DMA memory allocation support allows devices with less than 32-bit
308 addressing to allocate within the first 16MB of address space.
309 Disable if no such devices will be used.
314 bool "Symmetric multi-processing support"
316 This enables support for systems with more than one CPU. If you have
317 a system with only one CPU, say N. If you have a system with more
320 If you say N here, the kernel will run on uni- and multiprocessor
321 machines, but will use only one CPU of a multiprocessor machine. If
322 you say Y here, the kernel will run on many, but not all,
323 uniprocessor machines. On a uniprocessor machine, the kernel
324 will run faster if you say N here.
326 Note that if you say Y here and choose architecture "586" or
327 "Pentium" under "Processor family", the kernel will not work on 486
328 architectures. Similarly, multiprocessor kernels for the "PPro"
329 architecture may not work on all Pentium based boards.
331 People using multiprocessor machines who say Y here should also say
332 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
333 Management" code will be disabled if you say Y here.
335 See also <file:Documentation/x86/i386/IO-APIC.txt>,
336 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
337 <http://www.tldp.org/docs.html#howto>.
339 If you don't know what to do here, say N.
341 config X86_FEATURE_NAMES
342 bool "Processor feature human-readable names" if EMBEDDED
345 This option compiles in a table of x86 feature bits and corresponding
346 names. This is required to support /proc/cpuinfo and a few kernel
347 messages. You can disable this to save space, at the expense of
348 making those few kernel messages show numeric feature bits instead.
353 bool "Support x2apic"
354 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
356 This enables x2apic support on CPUs that have this feature.
358 This allows 32-bit apic IDs (so it can support very large systems),
359 and accesses the local apic via MSRs not via mmio.
361 If you don't know what to do here, say N.
364 bool "Enable MPS table" if ACPI || SFI
366 depends on X86_LOCAL_APIC
368 For old smp systems that do not have proper acpi support. Newer systems
369 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
372 bool "Support for big SMP systems with more than 8 CPUs"
373 depends on X86_32 && SMP
375 This option is needed for the systems that have more than 8 CPUs
379 depends on X86_GOLDFISH
382 config X86_EXTENDED_PLATFORM
383 bool "Support for extended (non-PC) x86 platforms"
386 If you disable this option then the kernel will only support
387 standard PC platforms. (which covers the vast majority of
390 If you enable this option then you'll be able to select support
391 for the following (non-PC) 32 bit x86 platforms:
392 Goldfish (Android emulator)
395 SGI 320/540 (Visual Workstation)
396 STA2X11-based (e.g. Northville)
397 Moorestown MID devices
399 If you have one of these systems, or if you want to build a
400 generic distribution kernel, say Y here - otherwise say N.
404 config X86_EXTENDED_PLATFORM
405 bool "Support for extended (non-PC) x86 platforms"
408 If you disable this option then the kernel will only support
409 standard PC platforms. (which covers the vast majority of
412 If you enable this option then you'll be able to select support
413 for the following (non-PC) 64 bit x86 platforms:
418 If you have one of these systems, or if you want to build a
419 generic distribution kernel, say Y here - otherwise say N.
421 # This is an alphabetically sorted list of 64 bit extended platforms
422 # Please maintain the alphabetic order if and when there are additions
424 bool "Numascale NumaChip"
426 depends on X86_EXTENDED_PLATFORM
429 depends on X86_X2APIC
430 depends on PCI_MMCONFIG
432 Adds support for Numascale NumaChip large-SMP systems. Needed to
433 enable more than ~168 cores.
434 If you don't have one of these, you should say N here.
438 select HYPERVISOR_GUEST
440 depends on X86_64 && PCI
441 depends on X86_EXTENDED_PLATFORM
444 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
445 supposed to run on these EM64T-based machines. Only choose this option
446 if you have one of these machines.
449 bool "SGI Ultraviolet"
451 depends on X86_EXTENDED_PLATFORM
453 depends on X86_X2APIC
456 This option is needed in order to support SGI Ultraviolet systems.
457 If you don't have one of these, you should say N here.
459 # Following is an alphabetically sorted list of 32 bit extended platforms
460 # Please maintain the alphabetic order if and when there are additions
463 bool "Goldfish (Virtual Platform)"
464 depends on X86_EXTENDED_PLATFORM
466 Enable support for the Goldfish virtual platform used primarily
467 for Android development. Unless you are building for the Android
468 Goldfish emulator say N here.
471 bool "CE4100 TV platform"
473 depends on PCI_GODIRECT
474 depends on X86_IO_APIC
476 depends on X86_EXTENDED_PLATFORM
477 select X86_REBOOTFIXUPS
479 select OF_EARLY_FLATTREE
481 Select for the Intel CE media processor (CE4100) SOC.
482 This option compiles in support for the CE4100 SOC for settop
483 boxes and media devices.
486 bool "Intel MID platform support"
488 depends on X86_EXTENDED_PLATFORM
489 depends on X86_PLATFORM_DEVICES
492 depends on X86_IO_APIC
498 select MFD_INTEL_MSIC
500 Select to build a kernel capable of supporting Intel MID (Mobile
501 Internet Device) platform systems which do not have the PCI legacy
502 interfaces. If you are building for a PC class system say N here.
504 Intel MID platforms are based on an Intel processor and chipset which
505 consume less power than most of the x86 derivatives.
507 config X86_INTEL_QUARK
508 bool "Intel Quark platform support"
510 depends on X86_EXTENDED_PLATFORM
511 depends on X86_PLATFORM_DEVICES
515 depends on X86_IO_APIC
520 Select to include support for Quark X1000 SoC.
521 Say Y here if you have a Quark based system such as the Arduino
522 compatible Intel Galileo.
524 config X86_INTEL_LPSS
525 bool "Intel Low Power Subsystem Support"
530 Select to build support for Intel Low Power Subsystem such as
531 found on Intel Lynxpoint PCH. Selecting this option enables
532 things like clock tree (common clock framework) and pincontrol
533 which are needed by the LPSS peripheral drivers.
535 config X86_AMD_PLATFORM_DEVICE
536 bool "AMD ACPI2Platform devices support"
541 Select to interpret AMD specific ACPI device to platform device
542 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
543 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
544 implemented under PINCTRL subsystem.
547 tristate "Intel SoC IOSF Sideband support for SoC platforms"
550 This option enables sideband register access support for Intel SoC
551 platforms. On these platforms the IOSF sideband is used in lieu of
552 MSR's for some register accesses, mostly but not limited to thermal
553 and power. Drivers may query the availability of this device to
554 determine if they need the sideband in order to work on these
555 platforms. The sideband is available on the following SoC products.
556 This list is not meant to be exclusive.
561 You should say Y if you are running a kernel on one of these SoC's.
563 config IOSF_MBI_DEBUG
564 bool "Enable IOSF sideband access through debugfs"
565 depends on IOSF_MBI && DEBUG_FS
567 Select this option to expose the IOSF sideband access registers (MCR,
568 MDR, MCRX) through debugfs to write and read register information from
569 different units on the SoC. This is most useful for obtaining device
570 state information for debug and analysis. As this is a general access
571 mechanism, users of this option would have specific knowledge of the
572 device they want to access.
574 If you don't require the option or are in doubt, say N.
577 bool "RDC R-321x SoC"
579 depends on X86_EXTENDED_PLATFORM
581 select X86_REBOOTFIXUPS
583 This option is needed for RDC R-321x system-on-chip, also known
585 If you don't have one of these chips, you should say N here.
587 config X86_32_NON_STANDARD
588 bool "Support non-standard 32-bit SMP architectures"
589 depends on X86_32 && SMP
590 depends on X86_EXTENDED_PLATFORM
592 This option compiles in the bigsmp and STA2X11 default
593 subarchitectures. It is intended for a generic binary
594 kernel. If you select them all, kernel will probe it one by
595 one and will fallback to default.
597 # Alphabetically sorted list of Non standard 32 bit platforms
599 config X86_SUPPORTS_MEMORY_FAILURE
601 # MCE code calls memory_failure():
603 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
604 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
605 depends on X86_64 || !SPARSEMEM
606 select ARCH_SUPPORTS_MEMORY_FAILURE
609 bool "STA2X11 Companion Chip Support"
610 depends on X86_32_NON_STANDARD && PCI
611 select X86_DEV_DMA_OPS
615 select ARCH_REQUIRE_GPIOLIB
618 This adds support for boards based on the STA2X11 IO-Hub,
619 a.k.a. "ConneXt". The chip is used in place of the standard
620 PC chipset, so all "standard" peripherals are missing. If this
621 option is selected the kernel will still be able to boot on
622 standard PC machines.
625 tristate "Eurobraille/Iris poweroff module"
628 The Iris machines from EuroBraille do not have APM or ACPI support
629 to shut themselves down properly. A special I/O sequence is
630 needed to do so, which is what this module does at
633 This is only for Iris machines from EuroBraille.
637 config SCHED_OMIT_FRAME_POINTER
639 prompt "Single-depth WCHAN output"
642 Calculate simpler /proc/<PID>/wchan values. If this option
643 is disabled then wchan values will recurse back to the
644 caller function. This provides more accurate wchan values,
645 at the expense of slightly more scheduling overhead.
647 If in doubt, say "Y".
649 menuconfig HYPERVISOR_GUEST
650 bool "Linux guest support"
652 Say Y here to enable options for running Linux under various hyper-
653 visors. This option enables basic hypervisor detection and platform
656 If you say N, all options in this submenu will be skipped and
657 disabled, and Linux guest support won't be built in.
662 bool "Enable paravirtualization code"
664 This changes the kernel so it can modify itself when it is run
665 under a hypervisor, potentially improving performance significantly
666 over full virtualization. However, when run without a hypervisor
667 the kernel is theoretically slower and slightly larger.
669 config PARAVIRT_DEBUG
670 bool "paravirt-ops debugging"
671 depends on PARAVIRT && DEBUG_KERNEL
673 Enable to debug paravirt_ops internals. Specifically, BUG if
674 a paravirt_op is missing when it is called.
676 config PARAVIRT_SPINLOCKS
677 bool "Paravirtualization layer for spinlocks"
678 depends on PARAVIRT && SMP
679 select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS
681 Paravirtualized spinlocks allow a pvops backend to replace the
682 spinlock implementation with something virtualization-friendly
683 (for example, block the virtual CPU rather than spinning).
685 It has a minimal impact on native kernels and gives a nice performance
686 benefit on paravirtualized KVM / Xen kernels.
688 If you are unsure how to answer this question, answer Y.
690 source "arch/x86/xen/Kconfig"
693 bool "KVM Guest support (including kvmclock)"
695 select PARAVIRT_CLOCK
698 This option enables various optimizations for running under the KVM
699 hypervisor. It includes a paravirtualized clock, so that instead
700 of relying on a PIT (or probably other) emulation by the
701 underlying device model, the host provides the guest with
702 timing infrastructure such as time of day, and system time
705 bool "Enable debug information for KVM Guests in debugfs"
706 depends on KVM_GUEST && DEBUG_FS
709 This option enables collection of various statistics for KVM guest.
710 Statistics are displayed in debugfs filesystem. Enabling this option
711 may incur significant overhead.
713 source "arch/x86/lguest/Kconfig"
715 config PARAVIRT_TIME_ACCOUNTING
716 bool "Paravirtual steal time accounting"
720 Select this option to enable fine granularity task steal time
721 accounting. Time spent executing other tasks in parallel with
722 the current vCPU is discounted from the vCPU power. To account for
723 that, there can be a small performance impact.
725 If in doubt, say N here.
727 config PARAVIRT_CLOCK
730 endif #HYPERVISOR_GUEST
735 source "arch/x86/Kconfig.cpu"
739 prompt "HPET Timer Support" if X86_32
741 Use the IA-PC HPET (High Precision Event Timer) to manage
742 time in preference to the PIT and RTC, if a HPET is
744 HPET is the next generation timer replacing legacy 8254s.
745 The HPET provides a stable time base on SMP
746 systems, unlike the TSC, but it is more expensive to access,
747 as it is off-chip. You can find the HPET spec at
748 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
750 You can safely choose Y here. However, HPET will only be
751 activated if the platform and the BIOS support this feature.
752 Otherwise the 8254 will be used for timing services.
754 Choose N to continue using the legacy 8254 timer.
756 config HPET_EMULATE_RTC
758 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
761 def_bool y if X86_INTEL_MID
762 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
764 depends on X86_INTEL_MID && SFI
766 APB timer is the replacement for 8254, HPET on X86 MID platforms.
767 The APBT provides a stable time base on SMP
768 systems, unlike the TSC, but it is more expensive to access,
769 as it is off-chip. APB timers are always running regardless of CPU
770 C states, they are used as per CPU clockevent device when possible.
772 # Mark as expert because too many people got it wrong.
773 # The code disables itself when not needed.
776 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
777 bool "Enable DMI scanning" if EXPERT
779 Enabled scanning of DMI to identify machine quirks. Say Y
780 here unless you have verified that your setup is not
781 affected by entries in the DMI blacklist. Required by PNP
785 bool "Old AMD GART IOMMU support"
787 depends on X86_64 && PCI && AMD_NB
789 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
790 GART based hardware IOMMUs.
792 The GART supports full DMA access for devices with 32-bit access
793 limitations, on systems with more than 3 GB. This is usually needed
794 for USB, sound, many IDE/SATA chipsets and some other devices.
796 Newer systems typically have a modern AMD IOMMU, supported via
797 the CONFIG_AMD_IOMMU=y config option.
799 In normal configurations this driver is only active when needed:
800 there's more than 3 GB of memory and the system contains a
801 32-bit limited device.
806 bool "IBM Calgary IOMMU support"
808 depends on X86_64 && PCI
810 Support for hardware IOMMUs in IBM's xSeries x366 and x460
811 systems. Needed to run systems with more than 3GB of memory
812 properly with 32-bit PCI devices that do not support DAC
813 (Double Address Cycle). Calgary also supports bus level
814 isolation, where all DMAs pass through the IOMMU. This
815 prevents them from going anywhere except their intended
816 destination. This catches hard-to-find kernel bugs and
817 mis-behaving drivers and devices that do not use the DMA-API
818 properly to set up their DMA buffers. The IOMMU can be
819 turned off at boot time with the iommu=off parameter.
820 Normally the kernel will make the right choice by itself.
823 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
825 prompt "Should Calgary be enabled by default?"
826 depends on CALGARY_IOMMU
828 Should Calgary be enabled by default? if you choose 'y', Calgary
829 will be used (if it exists). If you choose 'n', Calgary will not be
830 used even if it exists. If you choose 'n' and would like to use
831 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
834 # need this always selected by IOMMU for the VIA workaround
838 Support for software bounce buffers used on x86-64 systems
839 which don't have a hardware IOMMU. Using this PCI devices
840 which can only access 32-bits of memory can be used on systems
841 with more than 3 GB of memory.
846 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
849 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
850 depends on X86_64 && SMP && DEBUG_KERNEL
851 select CPUMASK_OFFSTACK
853 Enable maximum number of CPUS and NUMA Nodes for this architecture.
857 int "Maximum number of CPUs" if SMP && !MAXSMP
858 range 2 8 if SMP && X86_32 && !X86_BIGSMP
859 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
860 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
862 default "8192" if MAXSMP
863 default "32" if SMP && X86_BIGSMP
864 default "8" if SMP && X86_32
867 This allows you to specify the maximum number of CPUs which this
868 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
869 supported value is 8192, otherwise the maximum value is 512. The
870 minimum value which makes sense is 2.
872 This is purely to save memory - each supported CPU adds
873 approximately eight kilobytes to the kernel image.
876 bool "SMT (Hyperthreading) scheduler support"
879 SMT scheduler support improves the CPU scheduler's decision making
880 when dealing with Intel Pentium 4 chips with HyperThreading at a
881 cost of slightly increased overhead in some places. If unsure say
886 prompt "Multi-core scheduler support"
889 Multi-core scheduler support improves the CPU scheduler's decision
890 making when dealing with multi-core CPU chips at a cost of slightly
891 increased overhead in some places. If unsure say N here.
893 source "kernel/Kconfig.preempt"
897 depends on !SMP && X86_LOCAL_APIC
900 bool "Local APIC support on uniprocessors" if !PCI_MSI
902 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
904 A local APIC (Advanced Programmable Interrupt Controller) is an
905 integrated interrupt controller in the CPU. If you have a single-CPU
906 system which has a processor with a local APIC, you can say Y here to
907 enable and use it. If you say Y here even though your machine doesn't
908 have a local APIC, then the kernel will still run with no slowdown at
909 all. The local APIC supports CPU-generated self-interrupts (timer,
910 performance counters), and the NMI watchdog which detects hard
914 bool "IO-APIC support on uniprocessors"
915 depends on X86_UP_APIC
917 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
918 SMP-capable replacement for PC-style interrupt controllers. Most
919 SMP systems and many recent uniprocessor systems have one.
921 If you have a single-CPU system with an IO-APIC, you can say Y here
922 to use it. If you say Y here even though your machine doesn't have
923 an IO-APIC, then the kernel will still run with no slowdown at all.
925 config X86_LOCAL_APIC
927 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
928 select IRQ_DOMAIN_HIERARCHY
929 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
933 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
935 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
936 bool "Reroute for broken boot IRQs"
937 depends on X86_IO_APIC
939 This option enables a workaround that fixes a source of
940 spurious interrupts. This is recommended when threaded
941 interrupt handling is used on systems where the generation of
942 superfluous "boot interrupts" cannot be disabled.
944 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
945 entry in the chipset's IO-APIC is masked (as, e.g. the RT
946 kernel does during interrupt handling). On chipsets where this
947 boot IRQ generation cannot be disabled, this workaround keeps
948 the original IRQ line masked so that only the equivalent "boot
949 IRQ" is delivered to the CPUs. The workaround also tells the
950 kernel to set up the IRQ handler on the boot IRQ line. In this
951 way only one interrupt is delivered to the kernel. Otherwise
952 the spurious second interrupt may cause the kernel to bring
953 down (vital) interrupt lines.
955 Only affects "broken" chipsets. Interrupt sharing may be
956 increased on these systems.
959 bool "Machine Check / overheating reporting"
960 select GENERIC_ALLOCATOR
963 Machine Check support allows the processor to notify the
964 kernel if it detects a problem (e.g. overheating, data corruption).
965 The action the kernel takes depends on the severity of the problem,
966 ranging from warning messages to halting the machine.
970 prompt "Intel MCE features"
971 depends on X86_MCE && X86_LOCAL_APIC
973 Additional support for intel specific MCE features such as
978 prompt "AMD MCE features"
979 depends on X86_MCE && X86_LOCAL_APIC
981 Additional support for AMD specific MCE features such as
982 the DRAM Error Threshold.
984 config X86_ANCIENT_MCE
985 bool "Support for old Pentium 5 / WinChip machine checks"
986 depends on X86_32 && X86_MCE
988 Include support for machine check handling on old Pentium 5 or WinChip
989 systems. These typically need to be enabled explicitly on the command
992 config X86_MCE_THRESHOLD
993 depends on X86_MCE_AMD || X86_MCE_INTEL
996 config X86_MCE_INJECT
998 tristate "Machine check injector support"
1000 Provide support for injecting machine checks for testing purposes.
1001 If you don't know what a machine check is and you don't do kernel
1002 QA it is safe to say n.
1004 config X86_THERMAL_VECTOR
1006 depends on X86_MCE_INTEL
1008 config X86_LEGACY_VM86
1009 bool "Legacy VM86 support (obsolete)"
1013 This option allows user programs to put the CPU into V8086
1014 mode, which is an 80286-era approximation of 16-bit real mode.
1016 Some very old versions of X and/or vbetool require this option
1017 for user mode setting. Similarly, DOSEMU will use it if
1018 available to accelerate real mode DOS programs. However, any
1019 recent version of DOSEMU, X, or vbetool should be fully
1020 functional even without kernel VM86 support, as they will all
1021 fall back to (pretty well performing) software emulation.
1023 Anything that works on a 64-bit kernel is unlikely to need
1024 this option, as 64-bit kernels don't, and can't, support V8086
1025 mode. This option is also unrelated to 16-bit protected mode
1026 and is not needed to run most 16-bit programs under Wine.
1028 Enabling this option adds considerable attack surface to the
1029 kernel and slows down system calls and exception handling.
1031 Unless you use very old userspace or need the last drop of
1032 performance in your real mode DOS games and can't use KVM,
1037 default X86_LEGACY_VM86
1040 bool "Enable support for 16-bit segments" if EXPERT
1042 depends on MODIFY_LDT_SYSCALL
1044 This option is required by programs like Wine to run 16-bit
1045 protected mode legacy code on x86 processors. Disabling
1046 this option saves about 300 bytes on i386, or around 6K text
1047 plus 16K runtime memory on x86-64,
1051 depends on X86_16BIT && X86_32
1055 depends on X86_16BIT && X86_64
1057 config X86_VSYSCALL_EMULATION
1058 bool "Enable vsyscall emulation" if EXPERT
1062 This enables emulation of the legacy vsyscall page. Disabling
1063 it is roughly equivalent to booting with vsyscall=none, except
1064 that it will also disable the helpful warning if a program
1065 tries to use a vsyscall. With this option set to N, offending
1066 programs will just segfault, citing addresses of the form
1069 This option is required by many programs built before 2013, and
1070 care should be used even with newer programs if set to N.
1072 Disabling this option saves about 7K of kernel size and
1073 possibly 4K of additional runtime pagetable memory.
1076 tristate "Toshiba Laptop support"
1079 This adds a driver to safely access the System Management Mode of
1080 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1081 not work on models with a Phoenix BIOS. The System Management Mode
1082 is used to set the BIOS and power saving options on Toshiba portables.
1084 For information on utilities to make use of this driver see the
1085 Toshiba Linux utilities web site at:
1086 <http://www.buzzard.org.uk/toshiba/>.
1088 Say Y if you intend to run this kernel on a Toshiba portable.
1092 tristate "Dell i8k legacy laptop support"
1094 select SENSORS_DELL_SMM
1096 This option enables legacy /proc/i8k userspace interface in hwmon
1097 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1098 temperature and allows controlling fan speeds of Dell laptops via
1099 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1100 it reports also power and hotkey status. For fan speed control is
1101 needed userspace package i8kutils.
1103 Say Y if you intend to run this kernel on old Dell laptops or want to
1104 use userspace package i8kutils.
1107 config X86_REBOOTFIXUPS
1108 bool "Enable X86 board specific fixups for reboot"
1111 This enables chipset and/or board specific fixups to be done
1112 in order to get reboot to work correctly. This is only needed on
1113 some combinations of hardware and BIOS. The symptom, for which
1114 this config is intended, is when reboot ends with a stalled/hung
1117 Currently, the only fixup is for the Geode machines using
1118 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1120 Say Y if you want to enable the fixup. Currently, it's safe to
1121 enable this option even if you don't need it.
1125 tristate "CPU microcode loading support"
1126 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1130 If you say Y here, you will be able to update the microcode on
1131 certain Intel and AMD processors. The Intel support is for the
1132 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1133 Xeon etc. The AMD support is for families 0x10 and later. You will
1134 obviously need the actual microcode binary data itself which is not
1135 shipped with the Linux kernel.
1137 This option selects the general module only, you need to select
1138 at least one vendor specific module as well.
1140 To compile this driver as a module, choose M here: the module
1141 will be called microcode.
1143 config MICROCODE_INTEL
1144 bool "Intel microcode loading support"
1145 depends on MICROCODE
1149 This options enables microcode patch loading support for Intel
1152 For the current Intel microcode data package go to
1153 <https://downloadcenter.intel.com> and search for
1154 'Linux Processor Microcode Data File'.
1156 config MICROCODE_AMD
1157 bool "AMD microcode loading support"
1158 depends on MICROCODE
1161 If you select this option, microcode patch loading support for AMD
1162 processors will be enabled.
1164 config MICROCODE_OLD_INTERFACE
1166 depends on MICROCODE
1168 config MICROCODE_INTEL_EARLY
1171 config MICROCODE_AMD_EARLY
1174 config MICROCODE_EARLY
1175 bool "Early load microcode"
1176 depends on MICROCODE=y && BLK_DEV_INITRD
1177 select MICROCODE_INTEL_EARLY if MICROCODE_INTEL
1178 select MICROCODE_AMD_EARLY if MICROCODE_AMD
1181 This option provides functionality to read additional microcode data
1182 at the beginning of initrd image. The data tells kernel to load
1183 microcode to CPU's as early as possible. No functional change if no
1184 microcode data is glued to the initrd, therefore it's safe to say Y.
1187 tristate "/dev/cpu/*/msr - Model-specific register support"
1189 This device gives privileged processes access to the x86
1190 Model-Specific Registers (MSRs). It is a character device with
1191 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1192 MSR accesses are directed to a specific CPU on multi-processor
1196 tristate "/dev/cpu/*/cpuid - CPU information support"
1198 This device gives processes access to the x86 CPUID instruction to
1199 be executed on a specific processor. It is a character device
1200 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1204 prompt "High Memory Support"
1211 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1212 However, the address space of 32-bit x86 processors is only 4
1213 Gigabytes large. That means that, if you have a large amount of
1214 physical memory, not all of it can be "permanently mapped" by the
1215 kernel. The physical memory that's not permanently mapped is called
1218 If you are compiling a kernel which will never run on a machine with
1219 more than 1 Gigabyte total physical RAM, answer "off" here (default
1220 choice and suitable for most users). This will result in a "3GB/1GB"
1221 split: 3GB are mapped so that each process sees a 3GB virtual memory
1222 space and the remaining part of the 4GB virtual memory space is used
1223 by the kernel to permanently map as much physical memory as
1226 If the machine has between 1 and 4 Gigabytes physical RAM, then
1229 If more than 4 Gigabytes is used then answer "64GB" here. This
1230 selection turns Intel PAE (Physical Address Extension) mode on.
1231 PAE implements 3-level paging on IA32 processors. PAE is fully
1232 supported by Linux, PAE mode is implemented on all recent Intel
1233 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1234 then the kernel will not boot on CPUs that don't support PAE!
1236 The actual amount of total physical memory will either be
1237 auto detected or can be forced by using a kernel command line option
1238 such as "mem=256M". (Try "man bootparam" or see the documentation of
1239 your boot loader (lilo or loadlin) about how to pass options to the
1240 kernel at boot time.)
1242 If unsure, say "off".
1247 Select this if you have a 32-bit processor and between 1 and 4
1248 gigabytes of physical RAM.
1255 Select this if you have a 32-bit processor and more than 4
1256 gigabytes of physical RAM.
1261 prompt "Memory split" if EXPERT
1265 Select the desired split between kernel and user memory.
1267 If the address range available to the kernel is less than the
1268 physical memory installed, the remaining memory will be available
1269 as "high memory". Accessing high memory is a little more costly
1270 than low memory, as it needs to be mapped into the kernel first.
1271 Note that increasing the kernel address space limits the range
1272 available to user programs, making the address space there
1273 tighter. Selecting anything other than the default 3G/1G split
1274 will also likely make your kernel incompatible with binary-only
1277 If you are not absolutely sure what you are doing, leave this
1281 bool "3G/1G user/kernel split"
1282 config VMSPLIT_3G_OPT
1284 bool "3G/1G user/kernel split (for full 1G low memory)"
1286 bool "2G/2G user/kernel split"
1287 config VMSPLIT_2G_OPT
1289 bool "2G/2G user/kernel split (for full 2G low memory)"
1291 bool "1G/3G user/kernel split"
1296 default 0xB0000000 if VMSPLIT_3G_OPT
1297 default 0x80000000 if VMSPLIT_2G
1298 default 0x78000000 if VMSPLIT_2G_OPT
1299 default 0x40000000 if VMSPLIT_1G
1305 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1308 bool "PAE (Physical Address Extension) Support"
1309 depends on X86_32 && !HIGHMEM4G
1311 PAE is required for NX support, and furthermore enables
1312 larger swapspace support for non-overcommit purposes. It
1313 has the cost of more pagetable lookup overhead, and also
1314 consumes more pagetable space per process.
1316 config ARCH_PHYS_ADDR_T_64BIT
1318 depends on X86_64 || X86_PAE
1320 config ARCH_DMA_ADDR_T_64BIT
1322 depends on X86_64 || HIGHMEM64G
1324 config X86_DIRECT_GBPAGES
1326 depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1328 Certain kernel features effectively disable kernel
1329 linear 1 GB mappings (even if the CPU otherwise
1330 supports them), so don't confuse the user by printing
1331 that we have them enabled.
1333 # Common NUMA Features
1335 bool "Numa Memory Allocation and Scheduler Support"
1337 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1338 default y if X86_BIGSMP
1340 Enable NUMA (Non Uniform Memory Access) support.
1342 The kernel will try to allocate memory used by a CPU on the
1343 local memory controller of the CPU and add some more
1344 NUMA awareness to the kernel.
1346 For 64-bit this is recommended if the system is Intel Core i7
1347 (or later), AMD Opteron, or EM64T NUMA.
1349 For 32-bit this is only needed if you boot a 32-bit
1350 kernel on a 64-bit NUMA platform.
1352 Otherwise, you should say N.
1356 prompt "Old style AMD Opteron NUMA detection"
1357 depends on X86_64 && NUMA && PCI
1359 Enable AMD NUMA node topology detection. You should say Y here if
1360 you have a multi processor AMD system. This uses an old method to
1361 read the NUMA configuration directly from the builtin Northbridge
1362 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1363 which also takes priority if both are compiled in.
1365 config X86_64_ACPI_NUMA
1367 prompt "ACPI NUMA detection"
1368 depends on X86_64 && NUMA && ACPI && PCI
1371 Enable ACPI SRAT based node topology detection.
1373 # Some NUMA nodes have memory ranges that span
1374 # other nodes. Even though a pfn is valid and
1375 # between a node's start and end pfns, it may not
1376 # reside on that node. See memmap_init_zone()
1378 config NODES_SPAN_OTHER_NODES
1380 depends on X86_64_ACPI_NUMA
1383 bool "NUMA emulation"
1386 Enable NUMA emulation. A flat machine will be split
1387 into virtual nodes when booted with "numa=fake=N", where N is the
1388 number of nodes. This is only useful for debugging.
1391 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1393 default "10" if MAXSMP
1394 default "6" if X86_64
1396 depends on NEED_MULTIPLE_NODES
1398 Specify the maximum number of NUMA Nodes available on the target
1399 system. Increases memory reserved to accommodate various tables.
1401 config ARCH_HAVE_MEMORY_PRESENT
1403 depends on X86_32 && DISCONTIGMEM
1405 config NEED_NODE_MEMMAP_SIZE
1407 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1409 config ARCH_FLATMEM_ENABLE
1411 depends on X86_32 && !NUMA
1413 config ARCH_DISCONTIGMEM_ENABLE
1415 depends on NUMA && X86_32
1417 config ARCH_DISCONTIGMEM_DEFAULT
1419 depends on NUMA && X86_32
1421 config ARCH_SPARSEMEM_ENABLE
1423 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1424 select SPARSEMEM_STATIC if X86_32
1425 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1427 config ARCH_SPARSEMEM_DEFAULT
1431 config ARCH_SELECT_MEMORY_MODEL
1433 depends on ARCH_SPARSEMEM_ENABLE
1435 config ARCH_MEMORY_PROBE
1436 bool "Enable sysfs memory/probe interface"
1437 depends on X86_64 && MEMORY_HOTPLUG
1439 This option enables a sysfs memory/probe interface for testing.
1440 See Documentation/memory-hotplug.txt for more information.
1441 If you are unsure how to answer this question, answer N.
1443 config ARCH_PROC_KCORE_TEXT
1445 depends on X86_64 && PROC_KCORE
1447 config ILLEGAL_POINTER_VALUE
1450 default 0xdead000000000000 if X86_64
1454 config X86_PMEM_LEGACY_DEVICE
1457 config X86_PMEM_LEGACY
1458 tristate "Support non-standard NVDIMMs and ADR protected memory"
1459 depends on PHYS_ADDR_T_64BIT
1461 select X86_PMEM_LEGACY_DEVICE
1464 Treat memory marked using the non-standard e820 type of 12 as used
1465 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1466 The kernel will offer these regions to the 'pmem' driver so
1467 they can be used for persistent storage.
1472 bool "Allocate 3rd-level pagetables from highmem"
1475 The VM uses one page table entry for each page of physical memory.
1476 For systems with a lot of RAM, this can be wasteful of precious
1477 low memory. Setting this option will put user-space page table
1478 entries in high memory.
1480 config X86_CHECK_BIOS_CORRUPTION
1481 bool "Check for low memory corruption"
1483 Periodically check for memory corruption in low memory, which
1484 is suspected to be caused by BIOS. Even when enabled in the
1485 configuration, it is disabled at runtime. Enable it by
1486 setting "memory_corruption_check=1" on the kernel command
1487 line. By default it scans the low 64k of memory every 60
1488 seconds; see the memory_corruption_check_size and
1489 memory_corruption_check_period parameters in
1490 Documentation/kernel-parameters.txt to adjust this.
1492 When enabled with the default parameters, this option has
1493 almost no overhead, as it reserves a relatively small amount
1494 of memory and scans it infrequently. It both detects corruption
1495 and prevents it from affecting the running system.
1497 It is, however, intended as a diagnostic tool; if repeatable
1498 BIOS-originated corruption always affects the same memory,
1499 you can use memmap= to prevent the kernel from using that
1502 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1503 bool "Set the default setting of memory_corruption_check"
1504 depends on X86_CHECK_BIOS_CORRUPTION
1507 Set whether the default state of memory_corruption_check is
1510 config X86_RESERVE_LOW
1511 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1515 Specify the amount of low memory to reserve for the BIOS.
1517 The first page contains BIOS data structures that the kernel
1518 must not use, so that page must always be reserved.
1520 By default we reserve the first 64K of physical RAM, as a
1521 number of BIOSes are known to corrupt that memory range
1522 during events such as suspend/resume or monitor cable
1523 insertion, so it must not be used by the kernel.
1525 You can set this to 4 if you are absolutely sure that you
1526 trust the BIOS to get all its memory reservations and usages
1527 right. If you know your BIOS have problems beyond the
1528 default 64K area, you can set this to 640 to avoid using the
1529 entire low memory range.
1531 If you have doubts about the BIOS (e.g. suspend/resume does
1532 not work or there's kernel crashes after certain hardware
1533 hotplug events) then you might want to enable
1534 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1535 typical corruption patterns.
1537 Leave this to the default value of 64 if you are unsure.
1539 config MATH_EMULATION
1541 depends on MODIFY_LDT_SYSCALL
1542 prompt "Math emulation" if X86_32
1544 Linux can emulate a math coprocessor (used for floating point
1545 operations) if you don't have one. 486DX and Pentium processors have
1546 a math coprocessor built in, 486SX and 386 do not, unless you added
1547 a 487DX or 387, respectively. (The messages during boot time can
1548 give you some hints here ["man dmesg"].) Everyone needs either a
1549 coprocessor or this emulation.
1551 If you don't have a math coprocessor, you need to say Y here; if you
1552 say Y here even though you have a coprocessor, the coprocessor will
1553 be used nevertheless. (This behavior can be changed with the kernel
1554 command line option "no387", which comes handy if your coprocessor
1555 is broken. Try "man bootparam" or see the documentation of your boot
1556 loader (lilo or loadlin) about how to pass options to the kernel at
1557 boot time.) This means that it is a good idea to say Y here if you
1558 intend to use this kernel on different machines.
1560 More information about the internals of the Linux math coprocessor
1561 emulation can be found in <file:arch/x86/math-emu/README>.
1563 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1564 kernel, it won't hurt.
1568 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1570 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1571 the Memory Type Range Registers (MTRRs) may be used to control
1572 processor access to memory ranges. This is most useful if you have
1573 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1574 allows bus write transfers to be combined into a larger transfer
1575 before bursting over the PCI/AGP bus. This can increase performance
1576 of image write operations 2.5 times or more. Saying Y here creates a
1577 /proc/mtrr file which may be used to manipulate your processor's
1578 MTRRs. Typically the X server should use this.
1580 This code has a reasonably generic interface so that similar
1581 control registers on other processors can be easily supported
1584 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1585 Registers (ARRs) which provide a similar functionality to MTRRs. For
1586 these, the ARRs are used to emulate the MTRRs.
1587 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1588 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1589 write-combining. All of these processors are supported by this code
1590 and it makes sense to say Y here if you have one of them.
1592 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1593 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1594 can lead to all sorts of problems, so it's good to say Y here.
1596 You can safely say Y even if your machine doesn't have MTRRs, you'll
1597 just add about 9 KB to your kernel.
1599 See <file:Documentation/x86/mtrr.txt> for more information.
1601 config MTRR_SANITIZER
1603 prompt "MTRR cleanup support"
1606 Convert MTRR layout from continuous to discrete, so X drivers can
1607 add writeback entries.
1609 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1610 The largest mtrr entry size for a continuous block can be set with
1615 config MTRR_SANITIZER_ENABLE_DEFAULT
1616 int "MTRR cleanup enable value (0-1)"
1619 depends on MTRR_SANITIZER
1621 Enable mtrr cleanup default value
1623 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1624 int "MTRR cleanup spare reg num (0-7)"
1627 depends on MTRR_SANITIZER
1629 mtrr cleanup spare entries default, it can be changed via
1630 mtrr_spare_reg_nr=N on the kernel command line.
1634 prompt "x86 PAT support" if EXPERT
1637 Use PAT attributes to setup page level cache control.
1639 PATs are the modern equivalents of MTRRs and are much more
1640 flexible than MTRRs.
1642 Say N here if you see bootup problems (boot crash, boot hang,
1643 spontaneous reboots) or a non-working video driver.
1647 config ARCH_USES_PG_UNCACHED
1653 prompt "x86 architectural random number generator" if EXPERT
1655 Enable the x86 architectural RDRAND instruction
1656 (Intel Bull Mountain technology) to generate random numbers.
1657 If supported, this is a high bandwidth, cryptographically
1658 secure hardware random number generator.
1662 prompt "Supervisor Mode Access Prevention" if EXPERT
1664 Supervisor Mode Access Prevention (SMAP) is a security
1665 feature in newer Intel processors. There is a small
1666 performance cost if this enabled and turned on; there is
1667 also a small increase in the kernel size if this is enabled.
1671 config X86_INTEL_MPX
1672 prompt "Intel MPX (Memory Protection Extensions)"
1674 depends on CPU_SUP_INTEL
1676 MPX provides hardware features that can be used in
1677 conjunction with compiler-instrumented code to check
1678 memory references. It is designed to detect buffer
1679 overflow or underflow bugs.
1681 This option enables running applications which are
1682 instrumented or otherwise use MPX. It does not use MPX
1683 itself inside the kernel or to protect the kernel
1684 against bad memory references.
1686 Enabling this option will make the kernel larger:
1687 ~8k of kernel text and 36 bytes of data on a 64-bit
1688 defconfig. It adds a long to the 'mm_struct' which
1689 will increase the kernel memory overhead of each
1690 process and adds some branches to paths used during
1691 exec() and munmap().
1693 For details, see Documentation/x86/intel_mpx.txt
1698 bool "EFI runtime service support"
1701 select EFI_RUNTIME_WRAPPERS
1703 This enables the kernel to use EFI runtime services that are
1704 available (such as the EFI variable services).
1706 This option is only useful on systems that have EFI firmware.
1707 In addition, you should use the latest ELILO loader available
1708 at <http://elilo.sourceforge.net> in order to take advantage
1709 of EFI runtime services. However, even with this option, the
1710 resultant kernel should continue to boot on existing non-EFI
1714 bool "EFI stub support"
1715 depends on EFI && !X86_USE_3DNOW
1718 This kernel feature allows a bzImage to be loaded directly
1719 by EFI firmware without the use of a bootloader.
1721 See Documentation/efi-stub.txt for more information.
1724 bool "EFI mixed-mode support"
1725 depends on EFI_STUB && X86_64
1727 Enabling this feature allows a 64-bit kernel to be booted
1728 on a 32-bit firmware, provided that your CPU supports 64-bit
1731 Note that it is not possible to boot a mixed-mode enabled
1732 kernel via the EFI boot stub - a bootloader that supports
1733 the EFI handover protocol must be used.
1739 prompt "Enable seccomp to safely compute untrusted bytecode"
1741 This kernel feature is useful for number crunching applications
1742 that may need to compute untrusted bytecode during their
1743 execution. By using pipes or other transports made available to
1744 the process as file descriptors supporting the read/write
1745 syscalls, it's possible to isolate those applications in
1746 their own address space using seccomp. Once seccomp is
1747 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1748 and the task is only allowed to execute a few safe syscalls
1749 defined by each seccomp mode.
1751 If unsure, say Y. Only embedded should say N here.
1753 source kernel/Kconfig.hz
1756 bool "kexec system call"
1758 kexec is a system call that implements the ability to shutdown your
1759 current kernel, and to start another kernel. It is like a reboot
1760 but it is independent of the system firmware. And like a reboot
1761 you can start any kernel with it, not just Linux.
1763 The name comes from the similarity to the exec system call.
1765 It is an ongoing process to be certain the hardware in a machine
1766 is properly shutdown, so do not be surprised if this code does not
1767 initially work for you. As of this writing the exact hardware
1768 interface is strongly in flux, so no good recommendation can be
1772 bool "kexec file based system call"
1777 depends on CRYPTO_SHA256=y
1779 This is new version of kexec system call. This system call is
1780 file based and takes file descriptors as system call argument
1781 for kernel and initramfs as opposed to list of segments as
1782 accepted by previous system call.
1784 config KEXEC_VERIFY_SIG
1785 bool "Verify kernel signature during kexec_file_load() syscall"
1786 depends on KEXEC_FILE
1788 This option makes kernel signature verification mandatory for
1789 the kexec_file_load() syscall.
1791 In addition to that option, you need to enable signature
1792 verification for the corresponding kernel image type being
1793 loaded in order for this to work.
1795 config KEXEC_BZIMAGE_VERIFY_SIG
1796 bool "Enable bzImage signature verification support"
1797 depends on KEXEC_VERIFY_SIG
1798 depends on SIGNED_PE_FILE_VERIFICATION
1799 select SYSTEM_TRUSTED_KEYRING
1801 Enable bzImage signature verification support.
1804 bool "kernel crash dumps"
1805 depends on X86_64 || (X86_32 && HIGHMEM)
1807 Generate crash dump after being started by kexec.
1808 This should be normally only set in special crash dump kernels
1809 which are loaded in the main kernel with kexec-tools into
1810 a specially reserved region and then later executed after
1811 a crash by kdump/kexec. The crash dump kernel must be compiled
1812 to a memory address not used by the main kernel or BIOS using
1813 PHYSICAL_START, or it must be built as a relocatable image
1814 (CONFIG_RELOCATABLE=y).
1815 For more details see Documentation/kdump/kdump.txt
1819 depends on KEXEC && HIBERNATION
1821 Jump between original kernel and kexeced kernel and invoke
1822 code in physical address mode via KEXEC
1824 config PHYSICAL_START
1825 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1828 This gives the physical address where the kernel is loaded.
1830 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1831 bzImage will decompress itself to above physical address and
1832 run from there. Otherwise, bzImage will run from the address where
1833 it has been loaded by the boot loader and will ignore above physical
1836 In normal kdump cases one does not have to set/change this option
1837 as now bzImage can be compiled as a completely relocatable image
1838 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1839 address. This option is mainly useful for the folks who don't want
1840 to use a bzImage for capturing the crash dump and want to use a
1841 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1842 to be specifically compiled to run from a specific memory area
1843 (normally a reserved region) and this option comes handy.
1845 So if you are using bzImage for capturing the crash dump,
1846 leave the value here unchanged to 0x1000000 and set
1847 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1848 for capturing the crash dump change this value to start of
1849 the reserved region. In other words, it can be set based on
1850 the "X" value as specified in the "crashkernel=YM@XM"
1851 command line boot parameter passed to the panic-ed
1852 kernel. Please take a look at Documentation/kdump/kdump.txt
1853 for more details about crash dumps.
1855 Usage of bzImage for capturing the crash dump is recommended as
1856 one does not have to build two kernels. Same kernel can be used
1857 as production kernel and capture kernel. Above option should have
1858 gone away after relocatable bzImage support is introduced. But it
1859 is present because there are users out there who continue to use
1860 vmlinux for dump capture. This option should go away down the
1863 Don't change this unless you know what you are doing.
1866 bool "Build a relocatable kernel"
1869 This builds a kernel image that retains relocation information
1870 so it can be loaded someplace besides the default 1MB.
1871 The relocations tend to make the kernel binary about 10% larger,
1872 but are discarded at runtime.
1874 One use is for the kexec on panic case where the recovery kernel
1875 must live at a different physical address than the primary
1878 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1879 it has been loaded at and the compile time physical address
1880 (CONFIG_PHYSICAL_START) is used as the minimum location.
1882 config RANDOMIZE_BASE
1883 bool "Randomize the address of the kernel image"
1884 depends on RELOCATABLE
1887 Randomizes the physical and virtual address at which the
1888 kernel image is decompressed, as a security feature that
1889 deters exploit attempts relying on knowledge of the location
1890 of kernel internals.
1892 Entropy is generated using the RDRAND instruction if it is
1893 supported. If RDTSC is supported, it is used as well. If
1894 neither RDRAND nor RDTSC are supported, then randomness is
1895 read from the i8254 timer.
1897 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1898 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1899 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1900 minimum of 2MiB, only 10 bits of entropy is theoretically
1901 possible. At best, due to page table layouts, 64-bit can use
1902 9 bits of entropy and 32-bit uses 8 bits.
1906 config RANDOMIZE_BASE_MAX_OFFSET
1907 hex "Maximum kASLR offset allowed" if EXPERT
1908 depends on RANDOMIZE_BASE
1909 range 0x0 0x20000000 if X86_32
1910 default "0x20000000" if X86_32
1911 range 0x0 0x40000000 if X86_64
1912 default "0x40000000" if X86_64
1914 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1915 memory is used to determine the maximal offset in bytes that will
1916 be applied to the kernel when kernel Address Space Layout
1917 Randomization (kASLR) is active. This must be a multiple of
1920 On 32-bit this is limited to 512MiB by page table layouts. The
1923 On 64-bit this is limited by how the kernel fixmap page table is
1924 positioned, so this cannot be larger than 1GiB currently. Without
1925 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1926 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1927 modules area will shrink to compensate, up to the current maximum
1928 1GiB to 1GiB split. The default is 1GiB.
1930 If unsure, leave at the default value.
1932 # Relocation on x86 needs some additional build support
1933 config X86_NEED_RELOCS
1935 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1937 config PHYSICAL_ALIGN
1938 hex "Alignment value to which kernel should be aligned"
1940 range 0x2000 0x1000000 if X86_32
1941 range 0x200000 0x1000000 if X86_64
1943 This value puts the alignment restrictions on physical address
1944 where kernel is loaded and run from. Kernel is compiled for an
1945 address which meets above alignment restriction.
1947 If bootloader loads the kernel at a non-aligned address and
1948 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1949 address aligned to above value and run from there.
1951 If bootloader loads the kernel at a non-aligned address and
1952 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1953 load address and decompress itself to the address it has been
1954 compiled for and run from there. The address for which kernel is
1955 compiled already meets above alignment restrictions. Hence the
1956 end result is that kernel runs from a physical address meeting
1957 above alignment restrictions.
1959 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1960 this value must be a multiple of 0x200000.
1962 Don't change this unless you know what you are doing.
1965 bool "Support for hot-pluggable CPUs"
1968 Say Y here to allow turning CPUs off and on. CPUs can be
1969 controlled through /sys/devices/system/cpu.
1970 ( Note: power management support will enable this option
1971 automatically on SMP systems. )
1972 Say N if you want to disable CPU hotplug.
1974 config BOOTPARAM_HOTPLUG_CPU0
1975 bool "Set default setting of cpu0_hotpluggable"
1977 depends on HOTPLUG_CPU
1979 Set whether default state of cpu0_hotpluggable is on or off.
1981 Say Y here to enable CPU0 hotplug by default. If this switch
1982 is turned on, there is no need to give cpu0_hotplug kernel
1983 parameter and the CPU0 hotplug feature is enabled by default.
1985 Please note: there are two known CPU0 dependencies if you want
1986 to enable the CPU0 hotplug feature either by this switch or by
1987 cpu0_hotplug kernel parameter.
1989 First, resume from hibernate or suspend always starts from CPU0.
1990 So hibernate and suspend are prevented if CPU0 is offline.
1992 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1993 offline if any interrupt can not migrate out of CPU0. There may
1994 be other CPU0 dependencies.
1996 Please make sure the dependencies are under your control before
1997 you enable this feature.
1999 Say N if you don't want to enable CPU0 hotplug feature by default.
2000 You still can enable the CPU0 hotplug feature at boot by kernel
2001 parameter cpu0_hotplug.
2003 config DEBUG_HOTPLUG_CPU0
2005 prompt "Debug CPU0 hotplug"
2006 depends on HOTPLUG_CPU
2008 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2009 soon as possible and boots up userspace with CPU0 offlined. User
2010 can online CPU0 back after boot time.
2012 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2013 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2014 compilation or giving cpu0_hotplug kernel parameter at boot.
2020 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2021 depends on X86_32 || IA32_EMULATION
2023 Certain buggy versions of glibc will crash if they are
2024 presented with a 32-bit vDSO that is not mapped at the address
2025 indicated in its segment table.
2027 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2028 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2029 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2030 the only released version with the bug, but OpenSUSE 9
2031 contains a buggy "glibc 2.3.2".
2033 The symptom of the bug is that everything crashes on startup, saying:
2034 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2036 Saying Y here changes the default value of the vdso32 boot
2037 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2038 This works around the glibc bug but hurts performance.
2040 If unsure, say N: if you are compiling your own kernel, you
2041 are unlikely to be using a buggy version of glibc.
2044 bool "Built-in kernel command line"
2046 Allow for specifying boot arguments to the kernel at
2047 build time. On some systems (e.g. embedded ones), it is
2048 necessary or convenient to provide some or all of the
2049 kernel boot arguments with the kernel itself (that is,
2050 to not rely on the boot loader to provide them.)
2052 To compile command line arguments into the kernel,
2053 set this option to 'Y', then fill in the
2054 boot arguments in CONFIG_CMDLINE.
2056 Systems with fully functional boot loaders (i.e. non-embedded)
2057 should leave this option set to 'N'.
2060 string "Built-in kernel command string"
2061 depends on CMDLINE_BOOL
2064 Enter arguments here that should be compiled into the kernel
2065 image and used at boot time. If the boot loader provides a
2066 command line at boot time, it is appended to this string to
2067 form the full kernel command line, when the system boots.
2069 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2070 change this behavior.
2072 In most cases, the command line (whether built-in or provided
2073 by the boot loader) should specify the device for the root
2076 config CMDLINE_OVERRIDE
2077 bool "Built-in command line overrides boot loader arguments"
2078 depends on CMDLINE_BOOL
2080 Set this option to 'Y' to have the kernel ignore the boot loader
2081 command line, and use ONLY the built-in command line.
2083 This is used to work around broken boot loaders. This should
2084 be set to 'N' under normal conditions.
2086 config MODIFY_LDT_SYSCALL
2087 bool "Enable the LDT (local descriptor table)" if EXPERT
2090 Linux can allow user programs to install a per-process x86
2091 Local Descriptor Table (LDT) using the modify_ldt(2) system
2092 call. This is required to run 16-bit or segmented code such as
2093 DOSEMU or some Wine programs. It is also used by some very old
2094 threading libraries.
2096 Enabling this feature adds a small amount of overhead to
2097 context switches and increases the low-level kernel attack
2098 surface. Disabling it removes the modify_ldt(2) system call.
2100 Saying 'N' here may make sense for embedded or server kernels.
2102 source "kernel/livepatch/Kconfig"
2106 config ARCH_ENABLE_MEMORY_HOTPLUG
2108 depends on X86_64 || (X86_32 && HIGHMEM)
2110 config ARCH_ENABLE_MEMORY_HOTREMOVE
2112 depends on MEMORY_HOTPLUG
2114 config USE_PERCPU_NUMA_NODE_ID
2118 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2120 depends on X86_64 || X86_PAE
2122 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2124 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2126 menu "Power management and ACPI options"
2128 config ARCH_HIBERNATION_HEADER
2130 depends on X86_64 && HIBERNATION
2132 source "kernel/power/Kconfig"
2134 source "drivers/acpi/Kconfig"
2136 source "drivers/sfi/Kconfig"
2143 tristate "APM (Advanced Power Management) BIOS support"
2144 depends on X86_32 && PM_SLEEP
2146 APM is a BIOS specification for saving power using several different
2147 techniques. This is mostly useful for battery powered laptops with
2148 APM compliant BIOSes. If you say Y here, the system time will be
2149 reset after a RESUME operation, the /proc/apm device will provide
2150 battery status information, and user-space programs will receive
2151 notification of APM "events" (e.g. battery status change).
2153 If you select "Y" here, you can disable actual use of the APM
2154 BIOS by passing the "apm=off" option to the kernel at boot time.
2156 Note that the APM support is almost completely disabled for
2157 machines with more than one CPU.
2159 In order to use APM, you will need supporting software. For location
2160 and more information, read <file:Documentation/power/apm-acpi.txt>
2161 and the Battery Powered Linux mini-HOWTO, available from
2162 <http://www.tldp.org/docs.html#howto>.
2164 This driver does not spin down disk drives (see the hdparm(8)
2165 manpage ("man 8 hdparm") for that), and it doesn't turn off
2166 VESA-compliant "green" monitors.
2168 This driver does not support the TI 4000M TravelMate and the ACER
2169 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2170 desktop machines also don't have compliant BIOSes, and this driver
2171 may cause those machines to panic during the boot phase.
2173 Generally, if you don't have a battery in your machine, there isn't
2174 much point in using this driver and you should say N. If you get
2175 random kernel OOPSes or reboots that don't seem to be related to
2176 anything, try disabling/enabling this option (or disabling/enabling
2179 Some other things you should try when experiencing seemingly random,
2182 1) make sure that you have enough swap space and that it is
2184 2) pass the "no-hlt" option to the kernel
2185 3) switch on floating point emulation in the kernel and pass
2186 the "no387" option to the kernel
2187 4) pass the "floppy=nodma" option to the kernel
2188 5) pass the "mem=4M" option to the kernel (thereby disabling
2189 all but the first 4 MB of RAM)
2190 6) make sure that the CPU is not over clocked.
2191 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2192 8) disable the cache from your BIOS settings
2193 9) install a fan for the video card or exchange video RAM
2194 10) install a better fan for the CPU
2195 11) exchange RAM chips
2196 12) exchange the motherboard.
2198 To compile this driver as a module, choose M here: the
2199 module will be called apm.
2203 config APM_IGNORE_USER_SUSPEND
2204 bool "Ignore USER SUSPEND"
2206 This option will ignore USER SUSPEND requests. On machines with a
2207 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2208 series notebooks, it is necessary to say Y because of a BIOS bug.
2210 config APM_DO_ENABLE
2211 bool "Enable PM at boot time"
2213 Enable APM features at boot time. From page 36 of the APM BIOS
2214 specification: "When disabled, the APM BIOS does not automatically
2215 power manage devices, enter the Standby State, enter the Suspend
2216 State, or take power saving steps in response to CPU Idle calls."
2217 This driver will make CPU Idle calls when Linux is idle (unless this
2218 feature is turned off -- see "Do CPU IDLE calls", below). This
2219 should always save battery power, but more complicated APM features
2220 will be dependent on your BIOS implementation. You may need to turn
2221 this option off if your computer hangs at boot time when using APM
2222 support, or if it beeps continuously instead of suspending. Turn
2223 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2224 T400CDT. This is off by default since most machines do fine without
2229 bool "Make CPU Idle calls when idle"
2231 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2232 On some machines, this can activate improved power savings, such as
2233 a slowed CPU clock rate, when the machine is idle. These idle calls
2234 are made after the idle loop has run for some length of time (e.g.,
2235 333 mS). On some machines, this will cause a hang at boot time or
2236 whenever the CPU becomes idle. (On machines with more than one CPU,
2237 this option does nothing.)
2239 config APM_DISPLAY_BLANK
2240 bool "Enable console blanking using APM"
2242 Enable console blanking using the APM. Some laptops can use this to
2243 turn off the LCD backlight when the screen blanker of the Linux
2244 virtual console blanks the screen. Note that this is only used by
2245 the virtual console screen blanker, and won't turn off the backlight
2246 when using the X Window system. This also doesn't have anything to
2247 do with your VESA-compliant power-saving monitor. Further, this
2248 option doesn't work for all laptops -- it might not turn off your
2249 backlight at all, or it might print a lot of errors to the console,
2250 especially if you are using gpm.
2252 config APM_ALLOW_INTS
2253 bool "Allow interrupts during APM BIOS calls"
2255 Normally we disable external interrupts while we are making calls to
2256 the APM BIOS as a measure to lessen the effects of a badly behaving
2257 BIOS implementation. The BIOS should reenable interrupts if it
2258 needs to. Unfortunately, some BIOSes do not -- especially those in
2259 many of the newer IBM Thinkpads. If you experience hangs when you
2260 suspend, try setting this to Y. Otherwise, say N.
2264 source "drivers/cpufreq/Kconfig"
2266 source "drivers/cpuidle/Kconfig"
2268 source "drivers/idle/Kconfig"
2273 menu "Bus options (PCI etc.)"
2279 Find out whether you have a PCI motherboard. PCI is the name of a
2280 bus system, i.e. the way the CPU talks to the other stuff inside
2281 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2282 VESA. If you have PCI, say Y, otherwise N.
2285 prompt "PCI access mode"
2286 depends on X86_32 && PCI
2289 On PCI systems, the BIOS can be used to detect the PCI devices and
2290 determine their configuration. However, some old PCI motherboards
2291 have BIOS bugs and may crash if this is done. Also, some embedded
2292 PCI-based systems don't have any BIOS at all. Linux can also try to
2293 detect the PCI hardware directly without using the BIOS.
2295 With this option, you can specify how Linux should detect the
2296 PCI devices. If you choose "BIOS", the BIOS will be used,
2297 if you choose "Direct", the BIOS won't be used, and if you
2298 choose "MMConfig", then PCI Express MMCONFIG will be used.
2299 If you choose "Any", the kernel will try MMCONFIG, then the
2300 direct access method and falls back to the BIOS if that doesn't
2301 work. If unsure, go with the default, which is "Any".
2306 config PCI_GOMMCONFIG
2323 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2325 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2328 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2332 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2336 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2340 depends on PCI && XEN
2348 bool "Support mmconfig PCI config space access"
2349 depends on X86_64 && PCI && ACPI
2351 config PCI_CNB20LE_QUIRK
2352 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2355 Read the PCI windows out of the CNB20LE host bridge. This allows
2356 PCI hotplug to work on systems with the CNB20LE chipset which do
2359 There's no public spec for this chipset, and this functionality
2360 is known to be incomplete.
2362 You should say N unless you know you need this.
2364 source "drivers/pci/pcie/Kconfig"
2366 source "drivers/pci/Kconfig"
2368 # x86_64 have no ISA slots, but can have ISA-style DMA.
2370 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2373 Enables ISA-style DMA support for devices requiring such controllers.
2381 Find out whether you have ISA slots on your motherboard. ISA is the
2382 name of a bus system, i.e. the way the CPU talks to the other stuff
2383 inside your box. Other bus systems are PCI, EISA, MicroChannel
2384 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2385 newer boards don't support it. If you have ISA, say Y, otherwise N.
2391 The Extended Industry Standard Architecture (EISA) bus was
2392 developed as an open alternative to the IBM MicroChannel bus.
2394 The EISA bus provided some of the features of the IBM MicroChannel
2395 bus while maintaining backward compatibility with cards made for
2396 the older ISA bus. The EISA bus saw limited use between 1988 and
2397 1995 when it was made obsolete by the PCI bus.
2399 Say Y here if you are building a kernel for an EISA-based machine.
2403 source "drivers/eisa/Kconfig"
2406 tristate "NatSemi SCx200 support"
2408 This provides basic support for National Semiconductor's
2409 (now AMD's) Geode processors. The driver probes for the
2410 PCI-IDs of several on-chip devices, so its a good dependency
2411 for other scx200_* drivers.
2413 If compiled as a module, the driver is named scx200.
2415 config SCx200HR_TIMER
2416 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2420 This driver provides a clocksource built upon the on-chip
2421 27MHz high-resolution timer. Its also a workaround for
2422 NSC Geode SC-1100's buggy TSC, which loses time when the
2423 processor goes idle (as is done by the scheduler). The
2424 other workaround is idle=poll boot option.
2427 bool "One Laptop Per Child support"
2434 Add support for detecting the unique features of the OLPC
2438 bool "OLPC XO-1 Power Management"
2439 depends on OLPC && MFD_CS5535 && PM_SLEEP
2442 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2445 bool "OLPC XO-1 Real Time Clock"
2446 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2448 Add support for the XO-1 real time clock, which can be used as a
2449 programmable wakeup source.
2452 bool "OLPC XO-1 SCI extras"
2453 depends on OLPC && OLPC_XO1_PM
2459 Add support for SCI-based features of the OLPC XO-1 laptop:
2460 - EC-driven system wakeups
2464 - AC adapter status updates
2465 - Battery status updates
2467 config OLPC_XO15_SCI
2468 bool "OLPC XO-1.5 SCI extras"
2469 depends on OLPC && ACPI
2472 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2473 - EC-driven system wakeups
2474 - AC adapter status updates
2475 - Battery status updates
2478 bool "PCEngines ALIX System Support (LED setup)"
2481 This option enables system support for the PCEngines ALIX.
2482 At present this just sets up LEDs for GPIO control on
2483 ALIX2/3/6 boards. However, other system specific setup should
2486 Note: You must still enable the drivers for GPIO and LED support
2487 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2489 Note: You have to set alix.force=1 for boards with Award BIOS.
2492 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2495 This option enables system support for the Soekris Engineering net5501.
2498 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2502 This option enables system support for the Traverse Technologies GEOS.
2505 bool "Technologic Systems TS-5500 platform support"
2507 select CHECK_SIGNATURE
2511 This option enables system support for the Technologic Systems TS-5500.
2517 depends on CPU_SUP_AMD && PCI
2519 source "drivers/pcmcia/Kconfig"
2521 source "drivers/pci/hotplug/Kconfig"
2524 tristate "RapidIO support"
2528 If enabled this option will include drivers and the core
2529 infrastructure code to support RapidIO interconnect devices.
2531 source "drivers/rapidio/Kconfig"
2534 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2536 Firmwares often provide initial graphics framebuffers so the BIOS,
2537 bootloader or kernel can show basic video-output during boot for
2538 user-guidance and debugging. Historically, x86 used the VESA BIOS
2539 Extensions and EFI-framebuffers for this, which are mostly limited
2541 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2542 framebuffers so the new generic system-framebuffer drivers can be
2543 used on x86. If the framebuffer is not compatible with the generic
2544 modes, it is adverticed as fallback platform framebuffer so legacy
2545 drivers like efifb, vesafb and uvesafb can pick it up.
2546 If this option is not selected, all system framebuffers are always
2547 marked as fallback platform framebuffers as usual.
2549 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2550 not be able to pick up generic system framebuffers if this option
2551 is selected. You are highly encouraged to enable simplefb as
2552 replacement if you select this option. simplefb can correctly deal
2553 with generic system framebuffers. But you should still keep vesafb
2554 and others enabled as fallback if a system framebuffer is
2555 incompatible with simplefb.
2562 menu "Executable file formats / Emulations"
2564 source "fs/Kconfig.binfmt"
2566 config IA32_EMULATION
2567 bool "IA32 Emulation"
2570 select COMPAT_BINFMT_ELF
2571 select ARCH_WANT_OLD_COMPAT_IPC
2573 Include code to run legacy 32-bit programs under a
2574 64-bit kernel. You should likely turn this on, unless you're
2575 100% sure that you don't have any 32-bit programs left.
2578 tristate "IA32 a.out support"
2579 depends on IA32_EMULATION
2581 Support old a.out binaries in the 32bit emulation.
2584 bool "x32 ABI for 64-bit mode"
2587 Include code to run binaries for the x32 native 32-bit ABI
2588 for 64-bit processors. An x32 process gets access to the
2589 full 64-bit register file and wide data path while leaving
2590 pointers at 32 bits for smaller memory footprint.
2592 You will need a recent binutils (2.22 or later) with
2593 elf32_x86_64 support enabled to compile a kernel with this
2598 depends on IA32_EMULATION || X86_X32
2601 config COMPAT_FOR_U64_ALIGNMENT
2604 config SYSVIPC_COMPAT
2616 config HAVE_ATOMIC_IOMAP
2620 config X86_DEV_DMA_OPS
2622 depends on X86_64 || STA2X11
2624 config X86_DMA_REMAP
2632 source "net/Kconfig"
2634 source "drivers/Kconfig"
2636 source "drivers/firmware/Kconfig"
2640 source "arch/x86/Kconfig.debug"
2642 source "security/Kconfig"
2644 source "crypto/Kconfig"
2646 source "arch/x86/kvm/Kconfig"
2648 source "lib/Kconfig"