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
295 config PGTABLE_LEVELS
301 source "init/Kconfig"
302 source "kernel/Kconfig.freezer"
304 menu "Processor type and features"
307 bool "DMA memory allocation support" if EXPERT
310 DMA memory allocation support allows devices with less than 32-bit
311 addressing to allocate within the first 16MB of address space.
312 Disable if no such devices will be used.
317 bool "Symmetric multi-processing support"
319 This enables support for systems with more than one CPU. If you have
320 a system with only one CPU, say N. If you have a system with more
323 If you say N here, the kernel will run on uni- and multiprocessor
324 machines, but will use only one CPU of a multiprocessor machine. If
325 you say Y here, the kernel will run on many, but not all,
326 uniprocessor machines. On a uniprocessor machine, the kernel
327 will run faster if you say N here.
329 Note that if you say Y here and choose architecture "586" or
330 "Pentium" under "Processor family", the kernel will not work on 486
331 architectures. Similarly, multiprocessor kernels for the "PPro"
332 architecture may not work on all Pentium based boards.
334 People using multiprocessor machines who say Y here should also say
335 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
336 Management" code will be disabled if you say Y here.
338 See also <file:Documentation/x86/i386/IO-APIC.txt>,
339 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
340 <http://www.tldp.org/docs.html#howto>.
342 If you don't know what to do here, say N.
344 config X86_FEATURE_NAMES
345 bool "Processor feature human-readable names" if EMBEDDED
348 This option compiles in a table of x86 feature bits and corresponding
349 names. This is required to support /proc/cpuinfo and a few kernel
350 messages. You can disable this to save space, at the expense of
351 making those few kernel messages show numeric feature bits instead.
356 bool "Support x2apic"
357 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
359 This enables x2apic support on CPUs that have this feature.
361 This allows 32-bit apic IDs (so it can support very large systems),
362 and accesses the local apic via MSRs not via mmio.
364 If you don't know what to do here, say N.
367 bool "Enable MPS table" if ACPI || SFI
369 depends on X86_LOCAL_APIC
371 For old smp systems that do not have proper acpi support. Newer systems
372 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
375 bool "Support for big SMP systems with more than 8 CPUs"
376 depends on X86_32 && SMP
378 This option is needed for the systems that have more than 8 CPUs
382 depends on X86_GOLDFISH
385 config X86_EXTENDED_PLATFORM
386 bool "Support for extended (non-PC) x86 platforms"
389 If you disable this option then the kernel will only support
390 standard PC platforms. (which covers the vast majority of
393 If you enable this option then you'll be able to select support
394 for the following (non-PC) 32 bit x86 platforms:
395 Goldfish (Android emulator)
398 SGI 320/540 (Visual Workstation)
399 STA2X11-based (e.g. Northville)
400 Moorestown MID devices
402 If you have one of these systems, or if you want to build a
403 generic distribution kernel, say Y here - otherwise say N.
407 config X86_EXTENDED_PLATFORM
408 bool "Support for extended (non-PC) x86 platforms"
411 If you disable this option then the kernel will only support
412 standard PC platforms. (which covers the vast majority of
415 If you enable this option then you'll be able to select support
416 for the following (non-PC) 64 bit x86 platforms:
421 If you have one of these systems, or if you want to build a
422 generic distribution kernel, say Y here - otherwise say N.
424 # This is an alphabetically sorted list of 64 bit extended platforms
425 # Please maintain the alphabetic order if and when there are additions
427 bool "Numascale NumaChip"
429 depends on X86_EXTENDED_PLATFORM
432 depends on X86_X2APIC
433 depends on PCI_MMCONFIG
435 Adds support for Numascale NumaChip large-SMP systems. Needed to
436 enable more than ~168 cores.
437 If you don't have one of these, you should say N here.
441 select HYPERVISOR_GUEST
443 depends on X86_64 && PCI
444 depends on X86_EXTENDED_PLATFORM
447 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
448 supposed to run on these EM64T-based machines. Only choose this option
449 if you have one of these machines.
452 bool "SGI Ultraviolet"
454 depends on X86_EXTENDED_PLATFORM
456 depends on X86_X2APIC
459 This option is needed in order to support SGI Ultraviolet systems.
460 If you don't have one of these, you should say N here.
462 # Following is an alphabetically sorted list of 32 bit extended platforms
463 # Please maintain the alphabetic order if and when there are additions
466 bool "Goldfish (Virtual Platform)"
467 depends on X86_EXTENDED_PLATFORM
469 Enable support for the Goldfish virtual platform used primarily
470 for Android development. Unless you are building for the Android
471 Goldfish emulator say N here.
474 bool "CE4100 TV platform"
476 depends on PCI_GODIRECT
477 depends on X86_IO_APIC
479 depends on X86_EXTENDED_PLATFORM
480 select X86_REBOOTFIXUPS
482 select OF_EARLY_FLATTREE
484 Select for the Intel CE media processor (CE4100) SOC.
485 This option compiles in support for the CE4100 SOC for settop
486 boxes and media devices.
489 bool "Intel MID platform support"
491 depends on X86_EXTENDED_PLATFORM
492 depends on X86_PLATFORM_DEVICES
495 depends on X86_IO_APIC
501 select MFD_INTEL_MSIC
503 Select to build a kernel capable of supporting Intel MID (Mobile
504 Internet Device) platform systems which do not have the PCI legacy
505 interfaces. If you are building for a PC class system say N here.
507 Intel MID platforms are based on an Intel processor and chipset which
508 consume less power than most of the x86 derivatives.
510 config X86_INTEL_QUARK
511 bool "Intel Quark platform support"
513 depends on X86_EXTENDED_PLATFORM
514 depends on X86_PLATFORM_DEVICES
518 depends on X86_IO_APIC
523 Select to include support for Quark X1000 SoC.
524 Say Y here if you have a Quark based system such as the Arduino
525 compatible Intel Galileo.
527 config X86_INTEL_LPSS
528 bool "Intel Low Power Subsystem Support"
533 Select to build support for Intel Low Power Subsystem such as
534 found on Intel Lynxpoint PCH. Selecting this option enables
535 things like clock tree (common clock framework) and pincontrol
536 which are needed by the LPSS peripheral drivers.
538 config X86_AMD_PLATFORM_DEVICE
539 bool "AMD ACPI2Platform devices support"
544 Select to interpret AMD specific ACPI device to platform device
545 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
546 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
547 implemented under PINCTRL subsystem.
550 tristate "Intel SoC IOSF Sideband support for SoC platforms"
553 This option enables sideband register access support for Intel SoC
554 platforms. On these platforms the IOSF sideband is used in lieu of
555 MSR's for some register accesses, mostly but not limited to thermal
556 and power. Drivers may query the availability of this device to
557 determine if they need the sideband in order to work on these
558 platforms. The sideband is available on the following SoC products.
559 This list is not meant to be exclusive.
564 You should say Y if you are running a kernel on one of these SoC's.
566 config IOSF_MBI_DEBUG
567 bool "Enable IOSF sideband access through debugfs"
568 depends on IOSF_MBI && DEBUG_FS
570 Select this option to expose the IOSF sideband access registers (MCR,
571 MDR, MCRX) through debugfs to write and read register information from
572 different units on the SoC. This is most useful for obtaining device
573 state information for debug and analysis. As this is a general access
574 mechanism, users of this option would have specific knowledge of the
575 device they want to access.
577 If you don't require the option or are in doubt, say N.
580 bool "RDC R-321x SoC"
582 depends on X86_EXTENDED_PLATFORM
584 select X86_REBOOTFIXUPS
586 This option is needed for RDC R-321x system-on-chip, also known
588 If you don't have one of these chips, you should say N here.
590 config X86_32_NON_STANDARD
591 bool "Support non-standard 32-bit SMP architectures"
592 depends on X86_32 && SMP
593 depends on X86_EXTENDED_PLATFORM
595 This option compiles in the bigsmp and STA2X11 default
596 subarchitectures. It is intended for a generic binary
597 kernel. If you select them all, kernel will probe it one by
598 one and will fallback to default.
600 # Alphabetically sorted list of Non standard 32 bit platforms
602 config X86_SUPPORTS_MEMORY_FAILURE
604 # MCE code calls memory_failure():
606 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
607 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
608 depends on X86_64 || !SPARSEMEM
609 select ARCH_SUPPORTS_MEMORY_FAILURE
612 bool "STA2X11 Companion Chip Support"
613 depends on X86_32_NON_STANDARD && PCI
614 select X86_DEV_DMA_OPS
618 select ARCH_REQUIRE_GPIOLIB
621 This adds support for boards based on the STA2X11 IO-Hub,
622 a.k.a. "ConneXt". The chip is used in place of the standard
623 PC chipset, so all "standard" peripherals are missing. If this
624 option is selected the kernel will still be able to boot on
625 standard PC machines.
628 tristate "Eurobraille/Iris poweroff module"
631 The Iris machines from EuroBraille do not have APM or ACPI support
632 to shut themselves down properly. A special I/O sequence is
633 needed to do so, which is what this module does at
636 This is only for Iris machines from EuroBraille.
640 config SCHED_OMIT_FRAME_POINTER
642 prompt "Single-depth WCHAN output"
645 Calculate simpler /proc/<PID>/wchan values. If this option
646 is disabled then wchan values will recurse back to the
647 caller function. This provides more accurate wchan values,
648 at the expense of slightly more scheduling overhead.
650 If in doubt, say "Y".
652 menuconfig HYPERVISOR_GUEST
653 bool "Linux guest support"
655 Say Y here to enable options for running Linux under various hyper-
656 visors. This option enables basic hypervisor detection and platform
659 If you say N, all options in this submenu will be skipped and
660 disabled, and Linux guest support won't be built in.
665 bool "Enable paravirtualization code"
667 This changes the kernel so it can modify itself when it is run
668 under a hypervisor, potentially improving performance significantly
669 over full virtualization. However, when run without a hypervisor
670 the kernel is theoretically slower and slightly larger.
672 config PARAVIRT_DEBUG
673 bool "paravirt-ops debugging"
674 depends on PARAVIRT && DEBUG_KERNEL
676 Enable to debug paravirt_ops internals. Specifically, BUG if
677 a paravirt_op is missing when it is called.
679 config PARAVIRT_SPINLOCKS
680 bool "Paravirtualization layer for spinlocks"
681 depends on PARAVIRT && SMP
682 select UNINLINE_SPIN_UNLOCK if !QUEUED_SPINLOCKS
684 Paravirtualized spinlocks allow a pvops backend to replace the
685 spinlock implementation with something virtualization-friendly
686 (for example, block the virtual CPU rather than spinning).
688 It has a minimal impact on native kernels and gives a nice performance
689 benefit on paravirtualized KVM / Xen kernels.
691 If you are unsure how to answer this question, answer Y.
693 source "arch/x86/xen/Kconfig"
696 bool "KVM Guest support (including kvmclock)"
698 select PARAVIRT_CLOCK
701 This option enables various optimizations for running under the KVM
702 hypervisor. It includes a paravirtualized clock, so that instead
703 of relying on a PIT (or probably other) emulation by the
704 underlying device model, the host provides the guest with
705 timing infrastructure such as time of day, and system time
708 bool "Enable debug information for KVM Guests in debugfs"
709 depends on KVM_GUEST && DEBUG_FS
712 This option enables collection of various statistics for KVM guest.
713 Statistics are displayed in debugfs filesystem. Enabling this option
714 may incur significant overhead.
716 source "arch/x86/lguest/Kconfig"
718 config PARAVIRT_TIME_ACCOUNTING
719 bool "Paravirtual steal time accounting"
723 Select this option to enable fine granularity task steal time
724 accounting. Time spent executing other tasks in parallel with
725 the current vCPU is discounted from the vCPU power. To account for
726 that, there can be a small performance impact.
728 If in doubt, say N here.
730 config PARAVIRT_CLOCK
733 endif #HYPERVISOR_GUEST
738 source "arch/x86/Kconfig.cpu"
742 prompt "HPET Timer Support" if X86_32
744 Use the IA-PC HPET (High Precision Event Timer) to manage
745 time in preference to the PIT and RTC, if a HPET is
747 HPET is the next generation timer replacing legacy 8254s.
748 The HPET provides a stable time base on SMP
749 systems, unlike the TSC, but it is more expensive to access,
750 as it is off-chip. You can find the HPET spec at
751 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
753 You can safely choose Y here. However, HPET will only be
754 activated if the platform and the BIOS support this feature.
755 Otherwise the 8254 will be used for timing services.
757 Choose N to continue using the legacy 8254 timer.
759 config HPET_EMULATE_RTC
761 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
764 def_bool y if X86_INTEL_MID
765 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
767 depends on X86_INTEL_MID && SFI
769 APB timer is the replacement for 8254, HPET on X86 MID platforms.
770 The APBT provides a stable time base on SMP
771 systems, unlike the TSC, but it is more expensive to access,
772 as it is off-chip. APB timers are always running regardless of CPU
773 C states, they are used as per CPU clockevent device when possible.
775 # Mark as expert because too many people got it wrong.
776 # The code disables itself when not needed.
779 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
780 bool "Enable DMI scanning" if EXPERT
782 Enabled scanning of DMI to identify machine quirks. Say Y
783 here unless you have verified that your setup is not
784 affected by entries in the DMI blacklist. Required by PNP
788 bool "Old AMD GART IOMMU support"
790 depends on X86_64 && PCI && AMD_NB
792 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
793 GART based hardware IOMMUs.
795 The GART supports full DMA access for devices with 32-bit access
796 limitations, on systems with more than 3 GB. This is usually needed
797 for USB, sound, many IDE/SATA chipsets and some other devices.
799 Newer systems typically have a modern AMD IOMMU, supported via
800 the CONFIG_AMD_IOMMU=y config option.
802 In normal configurations this driver is only active when needed:
803 there's more than 3 GB of memory and the system contains a
804 32-bit limited device.
809 bool "IBM Calgary IOMMU support"
811 depends on X86_64 && PCI
813 Support for hardware IOMMUs in IBM's xSeries x366 and x460
814 systems. Needed to run systems with more than 3GB of memory
815 properly with 32-bit PCI devices that do not support DAC
816 (Double Address Cycle). Calgary also supports bus level
817 isolation, where all DMAs pass through the IOMMU. This
818 prevents them from going anywhere except their intended
819 destination. This catches hard-to-find kernel bugs and
820 mis-behaving drivers and devices that do not use the DMA-API
821 properly to set up their DMA buffers. The IOMMU can be
822 turned off at boot time with the iommu=off parameter.
823 Normally the kernel will make the right choice by itself.
826 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
828 prompt "Should Calgary be enabled by default?"
829 depends on CALGARY_IOMMU
831 Should Calgary be enabled by default? if you choose 'y', Calgary
832 will be used (if it exists). If you choose 'n', Calgary will not be
833 used even if it exists. If you choose 'n' and would like to use
834 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
837 # need this always selected by IOMMU for the VIA workaround
841 Support for software bounce buffers used on x86-64 systems
842 which don't have a hardware IOMMU. Using this PCI devices
843 which can only access 32-bits of memory can be used on systems
844 with more than 3 GB of memory.
849 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
852 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
853 depends on X86_64 && SMP && DEBUG_KERNEL
854 select CPUMASK_OFFSTACK
856 Enable maximum number of CPUS and NUMA Nodes for this architecture.
860 int "Maximum number of CPUs" if SMP && !MAXSMP
861 range 2 8 if SMP && X86_32 && !X86_BIGSMP
862 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
863 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
865 default "8192" if MAXSMP
866 default "32" if SMP && X86_BIGSMP
867 default "8" if SMP && X86_32
870 This allows you to specify the maximum number of CPUs which this
871 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
872 supported value is 8192, otherwise the maximum value is 512. The
873 minimum value which makes sense is 2.
875 This is purely to save memory - each supported CPU adds
876 approximately eight kilobytes to the kernel image.
879 bool "SMT (Hyperthreading) scheduler support"
882 SMT scheduler support improves the CPU scheduler's decision making
883 when dealing with Intel Pentium 4 chips with HyperThreading at a
884 cost of slightly increased overhead in some places. If unsure say
889 prompt "Multi-core scheduler support"
892 Multi-core scheduler support improves the CPU scheduler's decision
893 making when dealing with multi-core CPU chips at a cost of slightly
894 increased overhead in some places. If unsure say N here.
896 source "kernel/Kconfig.preempt"
900 depends on !SMP && X86_LOCAL_APIC
903 bool "Local APIC support on uniprocessors" if !PCI_MSI
905 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
907 A local APIC (Advanced Programmable Interrupt Controller) is an
908 integrated interrupt controller in the CPU. If you have a single-CPU
909 system which has a processor with a local APIC, you can say Y here to
910 enable and use it. If you say Y here even though your machine doesn't
911 have a local APIC, then the kernel will still run with no slowdown at
912 all. The local APIC supports CPU-generated self-interrupts (timer,
913 performance counters), and the NMI watchdog which detects hard
917 bool "IO-APIC support on uniprocessors"
918 depends on X86_UP_APIC
920 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
921 SMP-capable replacement for PC-style interrupt controllers. Most
922 SMP systems and many recent uniprocessor systems have one.
924 If you have a single-CPU system with an IO-APIC, you can say Y here
925 to use it. If you say Y here even though your machine doesn't have
926 an IO-APIC, then the kernel will still run with no slowdown at all.
928 config X86_LOCAL_APIC
930 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
931 select IRQ_DOMAIN_HIERARCHY
932 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
936 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
938 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
939 bool "Reroute for broken boot IRQs"
940 depends on X86_IO_APIC
942 This option enables a workaround that fixes a source of
943 spurious interrupts. This is recommended when threaded
944 interrupt handling is used on systems where the generation of
945 superfluous "boot interrupts" cannot be disabled.
947 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
948 entry in the chipset's IO-APIC is masked (as, e.g. the RT
949 kernel does during interrupt handling). On chipsets where this
950 boot IRQ generation cannot be disabled, this workaround keeps
951 the original IRQ line masked so that only the equivalent "boot
952 IRQ" is delivered to the CPUs. The workaround also tells the
953 kernel to set up the IRQ handler on the boot IRQ line. In this
954 way only one interrupt is delivered to the kernel. Otherwise
955 the spurious second interrupt may cause the kernel to bring
956 down (vital) interrupt lines.
958 Only affects "broken" chipsets. Interrupt sharing may be
959 increased on these systems.
962 bool "Machine Check / overheating reporting"
963 select GENERIC_ALLOCATOR
966 Machine Check support allows the processor to notify the
967 kernel if it detects a problem (e.g. overheating, data corruption).
968 The action the kernel takes depends on the severity of the problem,
969 ranging from warning messages to halting the machine.
973 prompt "Intel MCE features"
974 depends on X86_MCE && X86_LOCAL_APIC
976 Additional support for intel specific MCE features such as
981 prompt "AMD MCE features"
982 depends on X86_MCE && X86_LOCAL_APIC
984 Additional support for AMD specific MCE features such as
985 the DRAM Error Threshold.
987 config X86_ANCIENT_MCE
988 bool "Support for old Pentium 5 / WinChip machine checks"
989 depends on X86_32 && X86_MCE
991 Include support for machine check handling on old Pentium 5 or WinChip
992 systems. These typically need to be enabled explicitly on the command
995 config X86_MCE_THRESHOLD
996 depends on X86_MCE_AMD || X86_MCE_INTEL
999 config X86_MCE_INJECT
1001 tristate "Machine check injector support"
1003 Provide support for injecting machine checks for testing purposes.
1004 If you don't know what a machine check is and you don't do kernel
1005 QA it is safe to say n.
1007 config X86_THERMAL_VECTOR
1009 depends on X86_MCE_INTEL
1011 config X86_LEGACY_VM86
1012 bool "Legacy VM86 support"
1016 This option allows user programs to put the CPU into V8086
1017 mode, which is an 80286-era approximation of 16-bit real mode.
1019 Some very old versions of X and/or vbetool require this option
1020 for user mode setting. Similarly, DOSEMU will use it if
1021 available to accelerate real mode DOS programs. However, any
1022 recent version of DOSEMU, X, or vbetool should be fully
1023 functional even without kernel VM86 support, as they will all
1024 fall back to software emulation. Nevertheless, if you are using
1025 a 16-bit DOS program where 16-bit performance matters, vm86
1026 mode might be faster than emulation and you might want to
1029 Note that any app that works on a 64-bit kernel is unlikely to
1030 need this option, as 64-bit kernels don't, and can't, support
1031 V8086 mode. This option is also unrelated to 16-bit protected
1032 mode and is not needed to run most 16-bit programs under Wine.
1034 Enabling this option increases the complexity of the kernel
1035 and slows down exception handling a tiny bit.
1037 If unsure, say N here.
1041 default X86_LEGACY_VM86
1044 bool "Enable support for 16-bit segments" if EXPERT
1046 depends on MODIFY_LDT_SYSCALL
1048 This option is required by programs like Wine to run 16-bit
1049 protected mode legacy code on x86 processors. Disabling
1050 this option saves about 300 bytes on i386, or around 6K text
1051 plus 16K runtime memory on x86-64,
1055 depends on X86_16BIT && X86_32
1059 depends on X86_16BIT && X86_64
1061 config X86_VSYSCALL_EMULATION
1062 bool "Enable vsyscall emulation" if EXPERT
1066 This enables emulation of the legacy vsyscall page. Disabling
1067 it is roughly equivalent to booting with vsyscall=none, except
1068 that it will also disable the helpful warning if a program
1069 tries to use a vsyscall. With this option set to N, offending
1070 programs will just segfault, citing addresses of the form
1073 This option is required by many programs built before 2013, and
1074 care should be used even with newer programs if set to N.
1076 Disabling this option saves about 7K of kernel size and
1077 possibly 4K of additional runtime pagetable memory.
1080 tristate "Toshiba Laptop support"
1083 This adds a driver to safely access the System Management Mode of
1084 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1085 not work on models with a Phoenix BIOS. The System Management Mode
1086 is used to set the BIOS and power saving options on Toshiba portables.
1088 For information on utilities to make use of this driver see the
1089 Toshiba Linux utilities web site at:
1090 <http://www.buzzard.org.uk/toshiba/>.
1092 Say Y if you intend to run this kernel on a Toshiba portable.
1096 tristate "Dell i8k legacy laptop support"
1098 select SENSORS_DELL_SMM
1100 This option enables legacy /proc/i8k userspace interface in hwmon
1101 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1102 temperature and allows controlling fan speeds of Dell laptops via
1103 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1104 it reports also power and hotkey status. For fan speed control is
1105 needed userspace package i8kutils.
1107 Say Y if you intend to run this kernel on old Dell laptops or want to
1108 use userspace package i8kutils.
1111 config X86_REBOOTFIXUPS
1112 bool "Enable X86 board specific fixups for reboot"
1115 This enables chipset and/or board specific fixups to be done
1116 in order to get reboot to work correctly. This is only needed on
1117 some combinations of hardware and BIOS. The symptom, for which
1118 this config is intended, is when reboot ends with a stalled/hung
1121 Currently, the only fixup is for the Geode machines using
1122 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1124 Say Y if you want to enable the fixup. Currently, it's safe to
1125 enable this option even if you don't need it.
1129 bool "CPU microcode loading support"
1131 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1134 If you say Y here, you will be able to update the microcode on
1135 Intel and AMD processors. The Intel support is for the IA32 family,
1136 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1137 AMD support is for families 0x10 and later. You will obviously need
1138 the actual microcode binary data itself which is not shipped with
1141 The preferred method to load microcode from a detached initrd is described
1142 in Documentation/x86/early-microcode.txt. For that you need to enable
1143 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1144 initrd for microcode blobs.
1146 In addition, you can build-in the microcode into the kernel. For that you
1147 need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
1148 to the CONFIG_EXTRA_FIRMWARE config option.
1150 config MICROCODE_INTEL
1151 bool "Intel microcode loading support"
1152 depends on MICROCODE
1156 This options enables microcode patch loading support for Intel
1159 For the current Intel microcode data package go to
1160 <https://downloadcenter.intel.com> and search for
1161 'Linux Processor Microcode Data File'.
1163 config MICROCODE_AMD
1164 bool "AMD microcode loading support"
1165 depends on MICROCODE
1168 If you select this option, microcode patch loading support for AMD
1169 processors will be enabled.
1171 config MICROCODE_OLD_INTERFACE
1173 depends on MICROCODE
1176 tristate "/dev/cpu/*/msr - Model-specific register support"
1178 This device gives privileged processes access to the x86
1179 Model-Specific Registers (MSRs). It is a character device with
1180 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1181 MSR accesses are directed to a specific CPU on multi-processor
1185 tristate "/dev/cpu/*/cpuid - CPU information support"
1187 This device gives processes access to the x86 CPUID instruction to
1188 be executed on a specific processor. It is a character device
1189 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1193 prompt "High Memory Support"
1200 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1201 However, the address space of 32-bit x86 processors is only 4
1202 Gigabytes large. That means that, if you have a large amount of
1203 physical memory, not all of it can be "permanently mapped" by the
1204 kernel. The physical memory that's not permanently mapped is called
1207 If you are compiling a kernel which will never run on a machine with
1208 more than 1 Gigabyte total physical RAM, answer "off" here (default
1209 choice and suitable for most users). This will result in a "3GB/1GB"
1210 split: 3GB are mapped so that each process sees a 3GB virtual memory
1211 space and the remaining part of the 4GB virtual memory space is used
1212 by the kernel to permanently map as much physical memory as
1215 If the machine has between 1 and 4 Gigabytes physical RAM, then
1218 If more than 4 Gigabytes is used then answer "64GB" here. This
1219 selection turns Intel PAE (Physical Address Extension) mode on.
1220 PAE implements 3-level paging on IA32 processors. PAE is fully
1221 supported by Linux, PAE mode is implemented on all recent Intel
1222 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1223 then the kernel will not boot on CPUs that don't support PAE!
1225 The actual amount of total physical memory will either be
1226 auto detected or can be forced by using a kernel command line option
1227 such as "mem=256M". (Try "man bootparam" or see the documentation of
1228 your boot loader (lilo or loadlin) about how to pass options to the
1229 kernel at boot time.)
1231 If unsure, say "off".
1236 Select this if you have a 32-bit processor and between 1 and 4
1237 gigabytes of physical RAM.
1244 Select this if you have a 32-bit processor and more than 4
1245 gigabytes of physical RAM.
1250 prompt "Memory split" if EXPERT
1254 Select the desired split between kernel and user memory.
1256 If the address range available to the kernel is less than the
1257 physical memory installed, the remaining memory will be available
1258 as "high memory". Accessing high memory is a little more costly
1259 than low memory, as it needs to be mapped into the kernel first.
1260 Note that increasing the kernel address space limits the range
1261 available to user programs, making the address space there
1262 tighter. Selecting anything other than the default 3G/1G split
1263 will also likely make your kernel incompatible with binary-only
1266 If you are not absolutely sure what you are doing, leave this
1270 bool "3G/1G user/kernel split"
1271 config VMSPLIT_3G_OPT
1273 bool "3G/1G user/kernel split (for full 1G low memory)"
1275 bool "2G/2G user/kernel split"
1276 config VMSPLIT_2G_OPT
1278 bool "2G/2G user/kernel split (for full 2G low memory)"
1280 bool "1G/3G user/kernel split"
1285 default 0xB0000000 if VMSPLIT_3G_OPT
1286 default 0x80000000 if VMSPLIT_2G
1287 default 0x78000000 if VMSPLIT_2G_OPT
1288 default 0x40000000 if VMSPLIT_1G
1294 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1297 bool "PAE (Physical Address Extension) Support"
1298 depends on X86_32 && !HIGHMEM4G
1301 PAE is required for NX support, and furthermore enables
1302 larger swapspace support for non-overcommit purposes. It
1303 has the cost of more pagetable lookup overhead, and also
1304 consumes more pagetable space per process.
1306 config ARCH_PHYS_ADDR_T_64BIT
1308 depends on X86_64 || X86_PAE
1310 config ARCH_DMA_ADDR_T_64BIT
1312 depends on X86_64 || HIGHMEM64G
1314 config X86_DIRECT_GBPAGES
1316 depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
1318 Certain kernel features effectively disable kernel
1319 linear 1 GB mappings (even if the CPU otherwise
1320 supports them), so don't confuse the user by printing
1321 that we have them enabled.
1323 # Common NUMA Features
1325 bool "Numa Memory Allocation and Scheduler Support"
1327 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1328 default y if X86_BIGSMP
1330 Enable NUMA (Non Uniform Memory Access) support.
1332 The kernel will try to allocate memory used by a CPU on the
1333 local memory controller of the CPU and add some more
1334 NUMA awareness to the kernel.
1336 For 64-bit this is recommended if the system is Intel Core i7
1337 (or later), AMD Opteron, or EM64T NUMA.
1339 For 32-bit this is only needed if you boot a 32-bit
1340 kernel on a 64-bit NUMA platform.
1342 Otherwise, you should say N.
1346 prompt "Old style AMD Opteron NUMA detection"
1347 depends on X86_64 && NUMA && PCI
1349 Enable AMD NUMA node topology detection. You should say Y here if
1350 you have a multi processor AMD system. This uses an old method to
1351 read the NUMA configuration directly from the builtin Northbridge
1352 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1353 which also takes priority if both are compiled in.
1355 config X86_64_ACPI_NUMA
1357 prompt "ACPI NUMA detection"
1358 depends on X86_64 && NUMA && ACPI && PCI
1361 Enable ACPI SRAT based node topology detection.
1363 # Some NUMA nodes have memory ranges that span
1364 # other nodes. Even though a pfn is valid and
1365 # between a node's start and end pfns, it may not
1366 # reside on that node. See memmap_init_zone()
1368 config NODES_SPAN_OTHER_NODES
1370 depends on X86_64_ACPI_NUMA
1373 bool "NUMA emulation"
1376 Enable NUMA emulation. A flat machine will be split
1377 into virtual nodes when booted with "numa=fake=N", where N is the
1378 number of nodes. This is only useful for debugging.
1381 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1383 default "10" if MAXSMP
1384 default "6" if X86_64
1386 depends on NEED_MULTIPLE_NODES
1388 Specify the maximum number of NUMA Nodes available on the target
1389 system. Increases memory reserved to accommodate various tables.
1391 config ARCH_HAVE_MEMORY_PRESENT
1393 depends on X86_32 && DISCONTIGMEM
1395 config NEED_NODE_MEMMAP_SIZE
1397 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1399 config ARCH_FLATMEM_ENABLE
1401 depends on X86_32 && !NUMA
1403 config ARCH_DISCONTIGMEM_ENABLE
1405 depends on NUMA && X86_32
1407 config ARCH_DISCONTIGMEM_DEFAULT
1409 depends on NUMA && X86_32
1411 config ARCH_SPARSEMEM_ENABLE
1413 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1414 select SPARSEMEM_STATIC if X86_32
1415 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1417 config ARCH_SPARSEMEM_DEFAULT
1421 config ARCH_SELECT_MEMORY_MODEL
1423 depends on ARCH_SPARSEMEM_ENABLE
1425 config ARCH_MEMORY_PROBE
1426 bool "Enable sysfs memory/probe interface"
1427 depends on X86_64 && MEMORY_HOTPLUG
1429 This option enables a sysfs memory/probe interface for testing.
1430 See Documentation/memory-hotplug.txt for more information.
1431 If you are unsure how to answer this question, answer N.
1433 config ARCH_PROC_KCORE_TEXT
1435 depends on X86_64 && PROC_KCORE
1437 config ILLEGAL_POINTER_VALUE
1440 default 0xdead000000000000 if X86_64
1444 config X86_PMEM_LEGACY_DEVICE
1447 config X86_PMEM_LEGACY
1448 tristate "Support non-standard NVDIMMs and ADR protected memory"
1449 depends on PHYS_ADDR_T_64BIT
1451 select X86_PMEM_LEGACY_DEVICE
1454 Treat memory marked using the non-standard e820 type of 12 as used
1455 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1456 The kernel will offer these regions to the 'pmem' driver so
1457 they can be used for persistent storage.
1462 bool "Allocate 3rd-level pagetables from highmem"
1465 The VM uses one page table entry for each page of physical memory.
1466 For systems with a lot of RAM, this can be wasteful of precious
1467 low memory. Setting this option will put user-space page table
1468 entries in high memory.
1470 config X86_CHECK_BIOS_CORRUPTION
1471 bool "Check for low memory corruption"
1473 Periodically check for memory corruption in low memory, which
1474 is suspected to be caused by BIOS. Even when enabled in the
1475 configuration, it is disabled at runtime. Enable it by
1476 setting "memory_corruption_check=1" on the kernel command
1477 line. By default it scans the low 64k of memory every 60
1478 seconds; see the memory_corruption_check_size and
1479 memory_corruption_check_period parameters in
1480 Documentation/kernel-parameters.txt to adjust this.
1482 When enabled with the default parameters, this option has
1483 almost no overhead, as it reserves a relatively small amount
1484 of memory and scans it infrequently. It both detects corruption
1485 and prevents it from affecting the running system.
1487 It is, however, intended as a diagnostic tool; if repeatable
1488 BIOS-originated corruption always affects the same memory,
1489 you can use memmap= to prevent the kernel from using that
1492 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1493 bool "Set the default setting of memory_corruption_check"
1494 depends on X86_CHECK_BIOS_CORRUPTION
1497 Set whether the default state of memory_corruption_check is
1500 config X86_RESERVE_LOW
1501 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1505 Specify the amount of low memory to reserve for the BIOS.
1507 The first page contains BIOS data structures that the kernel
1508 must not use, so that page must always be reserved.
1510 By default we reserve the first 64K of physical RAM, as a
1511 number of BIOSes are known to corrupt that memory range
1512 during events such as suspend/resume or monitor cable
1513 insertion, so it must not be used by the kernel.
1515 You can set this to 4 if you are absolutely sure that you
1516 trust the BIOS to get all its memory reservations and usages
1517 right. If you know your BIOS have problems beyond the
1518 default 64K area, you can set this to 640 to avoid using the
1519 entire low memory range.
1521 If you have doubts about the BIOS (e.g. suspend/resume does
1522 not work or there's kernel crashes after certain hardware
1523 hotplug events) then you might want to enable
1524 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1525 typical corruption patterns.
1527 Leave this to the default value of 64 if you are unsure.
1529 config MATH_EMULATION
1531 depends on MODIFY_LDT_SYSCALL
1532 prompt "Math emulation" if X86_32
1534 Linux can emulate a math coprocessor (used for floating point
1535 operations) if you don't have one. 486DX and Pentium processors have
1536 a math coprocessor built in, 486SX and 386 do not, unless you added
1537 a 487DX or 387, respectively. (The messages during boot time can
1538 give you some hints here ["man dmesg"].) Everyone needs either a
1539 coprocessor or this emulation.
1541 If you don't have a math coprocessor, you need to say Y here; if you
1542 say Y here even though you have a coprocessor, the coprocessor will
1543 be used nevertheless. (This behavior can be changed with the kernel
1544 command line option "no387", which comes handy if your coprocessor
1545 is broken. Try "man bootparam" or see the documentation of your boot
1546 loader (lilo or loadlin) about how to pass options to the kernel at
1547 boot time.) This means that it is a good idea to say Y here if you
1548 intend to use this kernel on different machines.
1550 More information about the internals of the Linux math coprocessor
1551 emulation can be found in <file:arch/x86/math-emu/README>.
1553 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1554 kernel, it won't hurt.
1558 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1560 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1561 the Memory Type Range Registers (MTRRs) may be used to control
1562 processor access to memory ranges. This is most useful if you have
1563 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1564 allows bus write transfers to be combined into a larger transfer
1565 before bursting over the PCI/AGP bus. This can increase performance
1566 of image write operations 2.5 times or more. Saying Y here creates a
1567 /proc/mtrr file which may be used to manipulate your processor's
1568 MTRRs. Typically the X server should use this.
1570 This code has a reasonably generic interface so that similar
1571 control registers on other processors can be easily supported
1574 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1575 Registers (ARRs) which provide a similar functionality to MTRRs. For
1576 these, the ARRs are used to emulate the MTRRs.
1577 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1578 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1579 write-combining. All of these processors are supported by this code
1580 and it makes sense to say Y here if you have one of them.
1582 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1583 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1584 can lead to all sorts of problems, so it's good to say Y here.
1586 You can safely say Y even if your machine doesn't have MTRRs, you'll
1587 just add about 9 KB to your kernel.
1589 See <file:Documentation/x86/mtrr.txt> for more information.
1591 config MTRR_SANITIZER
1593 prompt "MTRR cleanup support"
1596 Convert MTRR layout from continuous to discrete, so X drivers can
1597 add writeback entries.
1599 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1600 The largest mtrr entry size for a continuous block can be set with
1605 config MTRR_SANITIZER_ENABLE_DEFAULT
1606 int "MTRR cleanup enable value (0-1)"
1609 depends on MTRR_SANITIZER
1611 Enable mtrr cleanup default value
1613 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1614 int "MTRR cleanup spare reg num (0-7)"
1617 depends on MTRR_SANITIZER
1619 mtrr cleanup spare entries default, it can be changed via
1620 mtrr_spare_reg_nr=N on the kernel command line.
1624 prompt "x86 PAT support" if EXPERT
1627 Use PAT attributes to setup page level cache control.
1629 PATs are the modern equivalents of MTRRs and are much more
1630 flexible than MTRRs.
1632 Say N here if you see bootup problems (boot crash, boot hang,
1633 spontaneous reboots) or a non-working video driver.
1637 config ARCH_USES_PG_UNCACHED
1643 prompt "x86 architectural random number generator" if EXPERT
1645 Enable the x86 architectural RDRAND instruction
1646 (Intel Bull Mountain technology) to generate random numbers.
1647 If supported, this is a high bandwidth, cryptographically
1648 secure hardware random number generator.
1652 prompt "Supervisor Mode Access Prevention" if EXPERT
1654 Supervisor Mode Access Prevention (SMAP) is a security
1655 feature in newer Intel processors. There is a small
1656 performance cost if this enabled and turned on; there is
1657 also a small increase in the kernel size if this is enabled.
1661 config X86_INTEL_MPX
1662 prompt "Intel MPX (Memory Protection Extensions)"
1664 depends on CPU_SUP_INTEL
1666 MPX provides hardware features that can be used in
1667 conjunction with compiler-instrumented code to check
1668 memory references. It is designed to detect buffer
1669 overflow or underflow bugs.
1671 This option enables running applications which are
1672 instrumented or otherwise use MPX. It does not use MPX
1673 itself inside the kernel or to protect the kernel
1674 against bad memory references.
1676 Enabling this option will make the kernel larger:
1677 ~8k of kernel text and 36 bytes of data on a 64-bit
1678 defconfig. It adds a long to the 'mm_struct' which
1679 will increase the kernel memory overhead of each
1680 process and adds some branches to paths used during
1681 exec() and munmap().
1683 For details, see Documentation/x86/intel_mpx.txt
1688 bool "EFI runtime service support"
1691 select EFI_RUNTIME_WRAPPERS
1693 This enables the kernel to use EFI runtime services that are
1694 available (such as the EFI variable services).
1696 This option is only useful on systems that have EFI firmware.
1697 In addition, you should use the latest ELILO loader available
1698 at <http://elilo.sourceforge.net> in order to take advantage
1699 of EFI runtime services. However, even with this option, the
1700 resultant kernel should continue to boot on existing non-EFI
1704 bool "EFI stub support"
1705 depends on EFI && !X86_USE_3DNOW
1708 This kernel feature allows a bzImage to be loaded directly
1709 by EFI firmware without the use of a bootloader.
1711 See Documentation/efi-stub.txt for more information.
1714 bool "EFI mixed-mode support"
1715 depends on EFI_STUB && X86_64
1717 Enabling this feature allows a 64-bit kernel to be booted
1718 on a 32-bit firmware, provided that your CPU supports 64-bit
1721 Note that it is not possible to boot a mixed-mode enabled
1722 kernel via the EFI boot stub - a bootloader that supports
1723 the EFI handover protocol must be used.
1729 prompt "Enable seccomp to safely compute untrusted bytecode"
1731 This kernel feature is useful for number crunching applications
1732 that may need to compute untrusted bytecode during their
1733 execution. By using pipes or other transports made available to
1734 the process as file descriptors supporting the read/write
1735 syscalls, it's possible to isolate those applications in
1736 their own address space using seccomp. Once seccomp is
1737 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1738 and the task is only allowed to execute a few safe syscalls
1739 defined by each seccomp mode.
1741 If unsure, say Y. Only embedded should say N here.
1743 source kernel/Kconfig.hz
1746 bool "kexec system call"
1749 kexec is a system call that implements the ability to shutdown your
1750 current kernel, and to start another kernel. It is like a reboot
1751 but it is independent of the system firmware. And like a reboot
1752 you can start any kernel with it, not just Linux.
1754 The name comes from the similarity to the exec system call.
1756 It is an ongoing process to be certain the hardware in a machine
1757 is properly shutdown, so do not be surprised if this code does not
1758 initially work for you. As of this writing the exact hardware
1759 interface is strongly in flux, so no good recommendation can be
1763 bool "kexec file based system call"
1768 depends on CRYPTO_SHA256=y
1770 This is new version of kexec system call. This system call is
1771 file based and takes file descriptors as system call argument
1772 for kernel and initramfs as opposed to list of segments as
1773 accepted by previous system call.
1775 config KEXEC_VERIFY_SIG
1776 bool "Verify kernel signature during kexec_file_load() syscall"
1777 depends on KEXEC_FILE
1779 This option makes kernel signature verification mandatory for
1780 the kexec_file_load() syscall.
1782 In addition to that option, you need to enable signature
1783 verification for the corresponding kernel image type being
1784 loaded in order for this to work.
1786 config KEXEC_BZIMAGE_VERIFY_SIG
1787 bool "Enable bzImage signature verification support"
1788 depends on KEXEC_VERIFY_SIG
1789 depends on SIGNED_PE_FILE_VERIFICATION
1790 select SYSTEM_TRUSTED_KEYRING
1792 Enable bzImage signature verification support.
1795 bool "kernel crash dumps"
1796 depends on X86_64 || (X86_32 && HIGHMEM)
1798 Generate crash dump after being started by kexec.
1799 This should be normally only set in special crash dump kernels
1800 which are loaded in the main kernel with kexec-tools into
1801 a specially reserved region and then later executed after
1802 a crash by kdump/kexec. The crash dump kernel must be compiled
1803 to a memory address not used by the main kernel or BIOS using
1804 PHYSICAL_START, or it must be built as a relocatable image
1805 (CONFIG_RELOCATABLE=y).
1806 For more details see Documentation/kdump/kdump.txt
1810 depends on KEXEC && HIBERNATION
1812 Jump between original kernel and kexeced kernel and invoke
1813 code in physical address mode via KEXEC
1815 config PHYSICAL_START
1816 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1819 This gives the physical address where the kernel is loaded.
1821 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1822 bzImage will decompress itself to above physical address and
1823 run from there. Otherwise, bzImage will run from the address where
1824 it has been loaded by the boot loader and will ignore above physical
1827 In normal kdump cases one does not have to set/change this option
1828 as now bzImage can be compiled as a completely relocatable image
1829 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1830 address. This option is mainly useful for the folks who don't want
1831 to use a bzImage for capturing the crash dump and want to use a
1832 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1833 to be specifically compiled to run from a specific memory area
1834 (normally a reserved region) and this option comes handy.
1836 So if you are using bzImage for capturing the crash dump,
1837 leave the value here unchanged to 0x1000000 and set
1838 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1839 for capturing the crash dump change this value to start of
1840 the reserved region. In other words, it can be set based on
1841 the "X" value as specified in the "crashkernel=YM@XM"
1842 command line boot parameter passed to the panic-ed
1843 kernel. Please take a look at Documentation/kdump/kdump.txt
1844 for more details about crash dumps.
1846 Usage of bzImage for capturing the crash dump is recommended as
1847 one does not have to build two kernels. Same kernel can be used
1848 as production kernel and capture kernel. Above option should have
1849 gone away after relocatable bzImage support is introduced. But it
1850 is present because there are users out there who continue to use
1851 vmlinux for dump capture. This option should go away down the
1854 Don't change this unless you know what you are doing.
1857 bool "Build a relocatable kernel"
1860 This builds a kernel image that retains relocation information
1861 so it can be loaded someplace besides the default 1MB.
1862 The relocations tend to make the kernel binary about 10% larger,
1863 but are discarded at runtime.
1865 One use is for the kexec on panic case where the recovery kernel
1866 must live at a different physical address than the primary
1869 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1870 it has been loaded at and the compile time physical address
1871 (CONFIG_PHYSICAL_START) is used as the minimum location.
1873 config RANDOMIZE_BASE
1874 bool "Randomize the address of the kernel image"
1875 depends on RELOCATABLE
1878 Randomizes the physical and virtual address at which the
1879 kernel image is decompressed, as a security feature that
1880 deters exploit attempts relying on knowledge of the location
1881 of kernel internals.
1883 Entropy is generated using the RDRAND instruction if it is
1884 supported. If RDTSC is supported, it is used as well. If
1885 neither RDRAND nor RDTSC are supported, then randomness is
1886 read from the i8254 timer.
1888 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1889 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1890 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1891 minimum of 2MiB, only 10 bits of entropy is theoretically
1892 possible. At best, due to page table layouts, 64-bit can use
1893 9 bits of entropy and 32-bit uses 8 bits.
1897 config RANDOMIZE_BASE_MAX_OFFSET
1898 hex "Maximum kASLR offset allowed" if EXPERT
1899 depends on RANDOMIZE_BASE
1900 range 0x0 0x20000000 if X86_32
1901 default "0x20000000" if X86_32
1902 range 0x0 0x40000000 if X86_64
1903 default "0x40000000" if X86_64
1905 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1906 memory is used to determine the maximal offset in bytes that will
1907 be applied to the kernel when kernel Address Space Layout
1908 Randomization (kASLR) is active. This must be a multiple of
1911 On 32-bit this is limited to 512MiB by page table layouts. The
1914 On 64-bit this is limited by how the kernel fixmap page table is
1915 positioned, so this cannot be larger than 1GiB currently. Without
1916 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1917 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1918 modules area will shrink to compensate, up to the current maximum
1919 1GiB to 1GiB split. The default is 1GiB.
1921 If unsure, leave at the default value.
1923 # Relocation on x86 needs some additional build support
1924 config X86_NEED_RELOCS
1926 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1928 config PHYSICAL_ALIGN
1929 hex "Alignment value to which kernel should be aligned"
1931 range 0x2000 0x1000000 if X86_32
1932 range 0x200000 0x1000000 if X86_64
1934 This value puts the alignment restrictions on physical address
1935 where kernel is loaded and run from. Kernel is compiled for an
1936 address which meets above alignment restriction.
1938 If bootloader loads the kernel at a non-aligned address and
1939 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1940 address aligned to above value and run from there.
1942 If bootloader loads the kernel at a non-aligned address and
1943 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1944 load address and decompress itself to the address it has been
1945 compiled for and run from there. The address for which kernel is
1946 compiled already meets above alignment restrictions. Hence the
1947 end result is that kernel runs from a physical address meeting
1948 above alignment restrictions.
1950 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1951 this value must be a multiple of 0x200000.
1953 Don't change this unless you know what you are doing.
1956 bool "Support for hot-pluggable CPUs"
1959 Say Y here to allow turning CPUs off and on. CPUs can be
1960 controlled through /sys/devices/system/cpu.
1961 ( Note: power management support will enable this option
1962 automatically on SMP systems. )
1963 Say N if you want to disable CPU hotplug.
1965 config BOOTPARAM_HOTPLUG_CPU0
1966 bool "Set default setting of cpu0_hotpluggable"
1968 depends on HOTPLUG_CPU
1970 Set whether default state of cpu0_hotpluggable is on or off.
1972 Say Y here to enable CPU0 hotplug by default. If this switch
1973 is turned on, there is no need to give cpu0_hotplug kernel
1974 parameter and the CPU0 hotplug feature is enabled by default.
1976 Please note: there are two known CPU0 dependencies if you want
1977 to enable the CPU0 hotplug feature either by this switch or by
1978 cpu0_hotplug kernel parameter.
1980 First, resume from hibernate or suspend always starts from CPU0.
1981 So hibernate and suspend are prevented if CPU0 is offline.
1983 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1984 offline if any interrupt can not migrate out of CPU0. There may
1985 be other CPU0 dependencies.
1987 Please make sure the dependencies are under your control before
1988 you enable this feature.
1990 Say N if you don't want to enable CPU0 hotplug feature by default.
1991 You still can enable the CPU0 hotplug feature at boot by kernel
1992 parameter cpu0_hotplug.
1994 config DEBUG_HOTPLUG_CPU0
1996 prompt "Debug CPU0 hotplug"
1997 depends on HOTPLUG_CPU
1999 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2000 soon as possible and boots up userspace with CPU0 offlined. User
2001 can online CPU0 back after boot time.
2003 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2004 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2005 compilation or giving cpu0_hotplug kernel parameter at boot.
2011 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2012 depends on X86_32 || IA32_EMULATION
2014 Certain buggy versions of glibc will crash if they are
2015 presented with a 32-bit vDSO that is not mapped at the address
2016 indicated in its segment table.
2018 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2019 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2020 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2021 the only released version with the bug, but OpenSUSE 9
2022 contains a buggy "glibc 2.3.2".
2024 The symptom of the bug is that everything crashes on startup, saying:
2025 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2027 Saying Y here changes the default value of the vdso32 boot
2028 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2029 This works around the glibc bug but hurts performance.
2031 If unsure, say N: if you are compiling your own kernel, you
2032 are unlikely to be using a buggy version of glibc.
2035 prompt "vsyscall table for legacy applications"
2037 default LEGACY_VSYSCALL_EMULATE
2039 Legacy user code that does not know how to find the vDSO expects
2040 to be able to issue three syscalls by calling fixed addresses in
2041 kernel space. Since this location is not randomized with ASLR,
2042 it can be used to assist security vulnerability exploitation.
2044 This setting can be changed at boot time via the kernel command
2045 line parameter vsyscall=[native|emulate|none].
2047 On a system with recent enough glibc (2.14 or newer) and no
2048 static binaries, you can say None without a performance penalty
2049 to improve security.
2051 If unsure, select "Emulate".
2053 config LEGACY_VSYSCALL_NATIVE
2056 Actual executable code is located in the fixed vsyscall
2057 address mapping, implementing time() efficiently. Since
2058 this makes the mapping executable, it can be used during
2059 security vulnerability exploitation (traditionally as
2060 ROP gadgets). This configuration is not recommended.
2062 config LEGACY_VSYSCALL_EMULATE
2065 The kernel traps and emulates calls into the fixed
2066 vsyscall address mapping. This makes the mapping
2067 non-executable, but it still contains known contents,
2068 which could be used in certain rare security vulnerability
2069 exploits. This configuration is recommended when userspace
2070 still uses the vsyscall area.
2072 config LEGACY_VSYSCALL_NONE
2075 There will be no vsyscall mapping at all. This will
2076 eliminate any risk of ASLR bypass due to the vsyscall
2077 fixed address mapping. Attempts to use the vsyscalls
2078 will be reported to dmesg, so that either old or
2079 malicious userspace programs can be identified.
2084 bool "Built-in kernel command line"
2086 Allow for specifying boot arguments to the kernel at
2087 build time. On some systems (e.g. embedded ones), it is
2088 necessary or convenient to provide some or all of the
2089 kernel boot arguments with the kernel itself (that is,
2090 to not rely on the boot loader to provide them.)
2092 To compile command line arguments into the kernel,
2093 set this option to 'Y', then fill in the
2094 boot arguments in CONFIG_CMDLINE.
2096 Systems with fully functional boot loaders (i.e. non-embedded)
2097 should leave this option set to 'N'.
2100 string "Built-in kernel command string"
2101 depends on CMDLINE_BOOL
2104 Enter arguments here that should be compiled into the kernel
2105 image and used at boot time. If the boot loader provides a
2106 command line at boot time, it is appended to this string to
2107 form the full kernel command line, when the system boots.
2109 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2110 change this behavior.
2112 In most cases, the command line (whether built-in or provided
2113 by the boot loader) should specify the device for the root
2116 config CMDLINE_OVERRIDE
2117 bool "Built-in command line overrides boot loader arguments"
2118 depends on CMDLINE_BOOL
2120 Set this option to 'Y' to have the kernel ignore the boot loader
2121 command line, and use ONLY the built-in command line.
2123 This is used to work around broken boot loaders. This should
2124 be set to 'N' under normal conditions.
2126 config MODIFY_LDT_SYSCALL
2127 bool "Enable the LDT (local descriptor table)" if EXPERT
2130 Linux can allow user programs to install a per-process x86
2131 Local Descriptor Table (LDT) using the modify_ldt(2) system
2132 call. This is required to run 16-bit or segmented code such as
2133 DOSEMU or some Wine programs. It is also used by some very old
2134 threading libraries.
2136 Enabling this feature adds a small amount of overhead to
2137 context switches and increases the low-level kernel attack
2138 surface. Disabling it removes the modify_ldt(2) system call.
2140 Saying 'N' here may make sense for embedded or server kernels.
2142 source "kernel/livepatch/Kconfig"
2146 config ARCH_ENABLE_MEMORY_HOTPLUG
2148 depends on X86_64 || (X86_32 && HIGHMEM)
2150 config ARCH_ENABLE_MEMORY_HOTREMOVE
2152 depends on MEMORY_HOTPLUG
2154 config USE_PERCPU_NUMA_NODE_ID
2158 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2160 depends on X86_64 || X86_PAE
2162 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2164 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2166 menu "Power management and ACPI options"
2168 config ARCH_HIBERNATION_HEADER
2170 depends on X86_64 && HIBERNATION
2172 source "kernel/power/Kconfig"
2174 source "drivers/acpi/Kconfig"
2176 source "drivers/sfi/Kconfig"
2183 tristate "APM (Advanced Power Management) BIOS support"
2184 depends on X86_32 && PM_SLEEP
2186 APM is a BIOS specification for saving power using several different
2187 techniques. This is mostly useful for battery powered laptops with
2188 APM compliant BIOSes. If you say Y here, the system time will be
2189 reset after a RESUME operation, the /proc/apm device will provide
2190 battery status information, and user-space programs will receive
2191 notification of APM "events" (e.g. battery status change).
2193 If you select "Y" here, you can disable actual use of the APM
2194 BIOS by passing the "apm=off" option to the kernel at boot time.
2196 Note that the APM support is almost completely disabled for
2197 machines with more than one CPU.
2199 In order to use APM, you will need supporting software. For location
2200 and more information, read <file:Documentation/power/apm-acpi.txt>
2201 and the Battery Powered Linux mini-HOWTO, available from
2202 <http://www.tldp.org/docs.html#howto>.
2204 This driver does not spin down disk drives (see the hdparm(8)
2205 manpage ("man 8 hdparm") for that), and it doesn't turn off
2206 VESA-compliant "green" monitors.
2208 This driver does not support the TI 4000M TravelMate and the ACER
2209 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2210 desktop machines also don't have compliant BIOSes, and this driver
2211 may cause those machines to panic during the boot phase.
2213 Generally, if you don't have a battery in your machine, there isn't
2214 much point in using this driver and you should say N. If you get
2215 random kernel OOPSes or reboots that don't seem to be related to
2216 anything, try disabling/enabling this option (or disabling/enabling
2219 Some other things you should try when experiencing seemingly random,
2222 1) make sure that you have enough swap space and that it is
2224 2) pass the "no-hlt" option to the kernel
2225 3) switch on floating point emulation in the kernel and pass
2226 the "no387" option to the kernel
2227 4) pass the "floppy=nodma" option to the kernel
2228 5) pass the "mem=4M" option to the kernel (thereby disabling
2229 all but the first 4 MB of RAM)
2230 6) make sure that the CPU is not over clocked.
2231 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2232 8) disable the cache from your BIOS settings
2233 9) install a fan for the video card or exchange video RAM
2234 10) install a better fan for the CPU
2235 11) exchange RAM chips
2236 12) exchange the motherboard.
2238 To compile this driver as a module, choose M here: the
2239 module will be called apm.
2243 config APM_IGNORE_USER_SUSPEND
2244 bool "Ignore USER SUSPEND"
2246 This option will ignore USER SUSPEND requests. On machines with a
2247 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2248 series notebooks, it is necessary to say Y because of a BIOS bug.
2250 config APM_DO_ENABLE
2251 bool "Enable PM at boot time"
2253 Enable APM features at boot time. From page 36 of the APM BIOS
2254 specification: "When disabled, the APM BIOS does not automatically
2255 power manage devices, enter the Standby State, enter the Suspend
2256 State, or take power saving steps in response to CPU Idle calls."
2257 This driver will make CPU Idle calls when Linux is idle (unless this
2258 feature is turned off -- see "Do CPU IDLE calls", below). This
2259 should always save battery power, but more complicated APM features
2260 will be dependent on your BIOS implementation. You may need to turn
2261 this option off if your computer hangs at boot time when using APM
2262 support, or if it beeps continuously instead of suspending. Turn
2263 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2264 T400CDT. This is off by default since most machines do fine without
2269 bool "Make CPU Idle calls when idle"
2271 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2272 On some machines, this can activate improved power savings, such as
2273 a slowed CPU clock rate, when the machine is idle. These idle calls
2274 are made after the idle loop has run for some length of time (e.g.,
2275 333 mS). On some machines, this will cause a hang at boot time or
2276 whenever the CPU becomes idle. (On machines with more than one CPU,
2277 this option does nothing.)
2279 config APM_DISPLAY_BLANK
2280 bool "Enable console blanking using APM"
2282 Enable console blanking using the APM. Some laptops can use this to
2283 turn off the LCD backlight when the screen blanker of the Linux
2284 virtual console blanks the screen. Note that this is only used by
2285 the virtual console screen blanker, and won't turn off the backlight
2286 when using the X Window system. This also doesn't have anything to
2287 do with your VESA-compliant power-saving monitor. Further, this
2288 option doesn't work for all laptops -- it might not turn off your
2289 backlight at all, or it might print a lot of errors to the console,
2290 especially if you are using gpm.
2292 config APM_ALLOW_INTS
2293 bool "Allow interrupts during APM BIOS calls"
2295 Normally we disable external interrupts while we are making calls to
2296 the APM BIOS as a measure to lessen the effects of a badly behaving
2297 BIOS implementation. The BIOS should reenable interrupts if it
2298 needs to. Unfortunately, some BIOSes do not -- especially those in
2299 many of the newer IBM Thinkpads. If you experience hangs when you
2300 suspend, try setting this to Y. Otherwise, say N.
2304 source "drivers/cpufreq/Kconfig"
2306 source "drivers/cpuidle/Kconfig"
2308 source "drivers/idle/Kconfig"
2313 menu "Bus options (PCI etc.)"
2319 Find out whether you have a PCI motherboard. PCI is the name of a
2320 bus system, i.e. the way the CPU talks to the other stuff inside
2321 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2322 VESA. If you have PCI, say Y, otherwise N.
2325 prompt "PCI access mode"
2326 depends on X86_32 && PCI
2329 On PCI systems, the BIOS can be used to detect the PCI devices and
2330 determine their configuration. However, some old PCI motherboards
2331 have BIOS bugs and may crash if this is done. Also, some embedded
2332 PCI-based systems don't have any BIOS at all. Linux can also try to
2333 detect the PCI hardware directly without using the BIOS.
2335 With this option, you can specify how Linux should detect the
2336 PCI devices. If you choose "BIOS", the BIOS will be used,
2337 if you choose "Direct", the BIOS won't be used, and if you
2338 choose "MMConfig", then PCI Express MMCONFIG will be used.
2339 If you choose "Any", the kernel will try MMCONFIG, then the
2340 direct access method and falls back to the BIOS if that doesn't
2341 work. If unsure, go with the default, which is "Any".
2346 config PCI_GOMMCONFIG
2363 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2365 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2368 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2372 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2376 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2380 depends on PCI && XEN
2388 bool "Support mmconfig PCI config space access"
2389 depends on X86_64 && PCI && ACPI
2391 config PCI_CNB20LE_QUIRK
2392 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2395 Read the PCI windows out of the CNB20LE host bridge. This allows
2396 PCI hotplug to work on systems with the CNB20LE chipset which do
2399 There's no public spec for this chipset, and this functionality
2400 is known to be incomplete.
2402 You should say N unless you know you need this.
2404 source "drivers/pci/pcie/Kconfig"
2406 source "drivers/pci/Kconfig"
2408 # x86_64 have no ISA slots, but can have ISA-style DMA.
2410 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2413 Enables ISA-style DMA support for devices requiring such controllers.
2421 Find out whether you have ISA slots on your motherboard. ISA is the
2422 name of a bus system, i.e. the way the CPU talks to the other stuff
2423 inside your box. Other bus systems are PCI, EISA, MicroChannel
2424 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2425 newer boards don't support it. If you have ISA, say Y, otherwise N.
2431 The Extended Industry Standard Architecture (EISA) bus was
2432 developed as an open alternative to the IBM MicroChannel bus.
2434 The EISA bus provided some of the features of the IBM MicroChannel
2435 bus while maintaining backward compatibility with cards made for
2436 the older ISA bus. The EISA bus saw limited use between 1988 and
2437 1995 when it was made obsolete by the PCI bus.
2439 Say Y here if you are building a kernel for an EISA-based machine.
2443 source "drivers/eisa/Kconfig"
2446 tristate "NatSemi SCx200 support"
2448 This provides basic support for National Semiconductor's
2449 (now AMD's) Geode processors. The driver probes for the
2450 PCI-IDs of several on-chip devices, so its a good dependency
2451 for other scx200_* drivers.
2453 If compiled as a module, the driver is named scx200.
2455 config SCx200HR_TIMER
2456 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2460 This driver provides a clocksource built upon the on-chip
2461 27MHz high-resolution timer. Its also a workaround for
2462 NSC Geode SC-1100's buggy TSC, which loses time when the
2463 processor goes idle (as is done by the scheduler). The
2464 other workaround is idle=poll boot option.
2467 bool "One Laptop Per Child support"
2474 Add support for detecting the unique features of the OLPC
2478 bool "OLPC XO-1 Power Management"
2479 depends on OLPC && MFD_CS5535 && PM_SLEEP
2482 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2485 bool "OLPC XO-1 Real Time Clock"
2486 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2488 Add support for the XO-1 real time clock, which can be used as a
2489 programmable wakeup source.
2492 bool "OLPC XO-1 SCI extras"
2493 depends on OLPC && OLPC_XO1_PM
2499 Add support for SCI-based features of the OLPC XO-1 laptop:
2500 - EC-driven system wakeups
2504 - AC adapter status updates
2505 - Battery status updates
2507 config OLPC_XO15_SCI
2508 bool "OLPC XO-1.5 SCI extras"
2509 depends on OLPC && ACPI
2512 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2513 - EC-driven system wakeups
2514 - AC adapter status updates
2515 - Battery status updates
2518 bool "PCEngines ALIX System Support (LED setup)"
2521 This option enables system support for the PCEngines ALIX.
2522 At present this just sets up LEDs for GPIO control on
2523 ALIX2/3/6 boards. However, other system specific setup should
2526 Note: You must still enable the drivers for GPIO and LED support
2527 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2529 Note: You have to set alix.force=1 for boards with Award BIOS.
2532 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2535 This option enables system support for the Soekris Engineering net5501.
2538 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2542 This option enables system support for the Traverse Technologies GEOS.
2545 bool "Technologic Systems TS-5500 platform support"
2547 select CHECK_SIGNATURE
2551 This option enables system support for the Technologic Systems TS-5500.
2557 depends on CPU_SUP_AMD && PCI
2559 source "drivers/pcmcia/Kconfig"
2561 source "drivers/pci/hotplug/Kconfig"
2564 tristate "RapidIO support"
2568 If enabled this option will include drivers and the core
2569 infrastructure code to support RapidIO interconnect devices.
2571 source "drivers/rapidio/Kconfig"
2574 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2576 Firmwares often provide initial graphics framebuffers so the BIOS,
2577 bootloader or kernel can show basic video-output during boot for
2578 user-guidance and debugging. Historically, x86 used the VESA BIOS
2579 Extensions and EFI-framebuffers for this, which are mostly limited
2581 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2582 framebuffers so the new generic system-framebuffer drivers can be
2583 used on x86. If the framebuffer is not compatible with the generic
2584 modes, it is adverticed as fallback platform framebuffer so legacy
2585 drivers like efifb, vesafb and uvesafb can pick it up.
2586 If this option is not selected, all system framebuffers are always
2587 marked as fallback platform framebuffers as usual.
2589 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2590 not be able to pick up generic system framebuffers if this option
2591 is selected. You are highly encouraged to enable simplefb as
2592 replacement if you select this option. simplefb can correctly deal
2593 with generic system framebuffers. But you should still keep vesafb
2594 and others enabled as fallback if a system framebuffer is
2595 incompatible with simplefb.
2602 menu "Executable file formats / Emulations"
2604 source "fs/Kconfig.binfmt"
2606 config IA32_EMULATION
2607 bool "IA32 Emulation"
2610 select COMPAT_BINFMT_ELF
2611 select ARCH_WANT_OLD_COMPAT_IPC
2613 Include code to run legacy 32-bit programs under a
2614 64-bit kernel. You should likely turn this on, unless you're
2615 100% sure that you don't have any 32-bit programs left.
2618 tristate "IA32 a.out support"
2619 depends on IA32_EMULATION
2621 Support old a.out binaries in the 32bit emulation.
2624 bool "x32 ABI for 64-bit mode"
2627 Include code to run binaries for the x32 native 32-bit ABI
2628 for 64-bit processors. An x32 process gets access to the
2629 full 64-bit register file and wide data path while leaving
2630 pointers at 32 bits for smaller memory footprint.
2632 You will need a recent binutils (2.22 or later) with
2633 elf32_x86_64 support enabled to compile a kernel with this
2638 depends on IA32_EMULATION || X86_X32
2641 config COMPAT_FOR_U64_ALIGNMENT
2644 config SYSVIPC_COMPAT
2656 config HAVE_ATOMIC_IOMAP
2660 config X86_DEV_DMA_OPS
2662 depends on X86_64 || STA2X11
2664 config X86_DMA_REMAP
2672 source "net/Kconfig"
2674 source "drivers/Kconfig"
2676 source "drivers/firmware/Kconfig"
2680 source "arch/x86/Kconfig.debug"
2682 source "security/Kconfig"
2684 source "crypto/Kconfig"
2686 source "arch/x86/kvm/Kconfig"
2688 source "lib/Kconfig"
projects / firefly-linux-kernel-4.4.55.git / blob