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
18 select X86_DEV_DMA_OPS
19 select ARCH_USE_CMPXCHG_LOCKREF
25 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
26 select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
27 select ARCH_HAS_FAST_MULTIPLIER
28 select ARCH_HAS_GCOV_PROFILE_ALL
29 select ARCH_MIGHT_HAVE_PC_PARPORT
30 select ARCH_MIGHT_HAVE_PC_SERIO
31 select HAVE_AOUT if X86_32
32 select HAVE_UNSTABLE_SCHED_CLOCK
33 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
34 select ARCH_SUPPORTS_INT128 if X86_64
37 select HAVE_PCSPKR_PLATFORM
38 select HAVE_PERF_EVENTS
39 select HAVE_IOREMAP_PROT
42 select HAVE_MEMBLOCK_NODE_MAP
43 select ARCH_DISCARD_MEMBLOCK
44 select ARCH_WANT_OPTIONAL_GPIOLIB
45 select ARCH_WANT_FRAME_POINTERS
47 select HAVE_DMA_CONTIGUOUS
48 select HAVE_KRETPROBES
49 select GENERIC_EARLY_IOREMAP
51 select HAVE_KPROBES_ON_FTRACE
52 select HAVE_FTRACE_MCOUNT_RECORD
53 select HAVE_FENTRY if X86_64
54 select HAVE_C_RECORDMCOUNT
55 select HAVE_DYNAMIC_FTRACE
56 select HAVE_DYNAMIC_FTRACE_WITH_REGS
57 select HAVE_FUNCTION_TRACER
58 select HAVE_FUNCTION_GRAPH_TRACER
59 select HAVE_FUNCTION_GRAPH_FP_TEST
60 select HAVE_SYSCALL_TRACEPOINTS
61 select SYSCTL_EXCEPTION_TRACE
64 select HAVE_ARCH_TRACEHOOK
65 select HAVE_GENERIC_DMA_COHERENT if X86_32
66 select HAVE_EFFICIENT_UNALIGNED_ACCESS
67 select USER_STACKTRACE_SUPPORT
68 select HAVE_REGS_AND_STACK_ACCESS_API
69 select HAVE_DMA_API_DEBUG
70 select HAVE_KERNEL_GZIP
71 select HAVE_KERNEL_BZIP2
72 select HAVE_KERNEL_LZMA
74 select HAVE_KERNEL_LZO
75 select HAVE_KERNEL_LZ4
76 select HAVE_HW_BREAKPOINT
77 select HAVE_MIXED_BREAKPOINTS_REGS
79 select HAVE_PERF_EVENTS_NMI
81 select HAVE_PERF_USER_STACK_DUMP
82 select HAVE_DEBUG_KMEMLEAK
84 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
85 select HAVE_CMPXCHG_LOCAL
86 select HAVE_CMPXCHG_DOUBLE
87 select HAVE_ARCH_KMEMCHECK
88 select HAVE_ARCH_KASAN if X86_64 && SPARSEMEM_VMEMMAP
89 select HAVE_USER_RETURN_NOTIFIER
90 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
91 select HAVE_ARCH_JUMP_LABEL
92 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
94 select GENERIC_FIND_FIRST_BIT
95 select GENERIC_IRQ_PROBE
96 select GENERIC_PENDING_IRQ if SMP
97 select GENERIC_IRQ_SHOW
98 select GENERIC_CLOCKEVENTS_MIN_ADJUST
99 select IRQ_FORCED_THREADING
100 select HAVE_BPF_JIT if X86_64
101 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
102 select ARCH_HAS_SG_CHAIN
104 select ARCH_HAVE_NMI_SAFE_CMPXCHG
106 select DCACHE_WORD_ACCESS
107 select GENERIC_SMP_IDLE_THREAD
108 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
109 select HAVE_ARCH_SECCOMP_FILTER
110 select BUILDTIME_EXTABLE_SORT
111 select GENERIC_CMOS_UPDATE
112 select HAVE_ARCH_SOFT_DIRTY if X86_64
113 select CLOCKSOURCE_WATCHDOG
114 select GENERIC_CLOCKEVENTS
115 select ARCH_CLOCKSOURCE_DATA
116 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
117 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
118 select GENERIC_TIME_VSYSCALL
119 select GENERIC_STRNCPY_FROM_USER
120 select GENERIC_STRNLEN_USER
121 select HAVE_CONTEXT_TRACKING if X86_64
122 select HAVE_IRQ_TIME_ACCOUNTING
124 select MODULES_USE_ELF_REL if X86_32
125 select MODULES_USE_ELF_RELA if X86_64
126 select CLONE_BACKWARDS if X86_32
127 select ARCH_USE_BUILTIN_BSWAP
128 select ARCH_USE_QUEUE_RWLOCK
129 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
130 select OLD_SIGACTION if X86_32
131 select COMPAT_OLD_SIGACTION if IA32_EMULATION
133 select HAVE_DEBUG_STACKOVERFLOW
134 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
135 select HAVE_CC_STACKPROTECTOR
136 select GENERIC_CPU_AUTOPROBE
137 select HAVE_ARCH_AUDITSYSCALL
138 select ARCH_SUPPORTS_ATOMIC_RMW
139 select HAVE_ACPI_APEI if ACPI
140 select HAVE_ACPI_APEI_NMI if ACPI
141 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
142 select X86_FEATURE_NAMES if PROC_FS
145 config INSTRUCTION_DECODER
147 depends on KPROBES || PERF_EVENTS || UPROBES
149 config PERF_EVENTS_INTEL_UNCORE
151 depends on PERF_EVENTS && CPU_SUP_INTEL && PCI
155 default "elf32-i386" if X86_32
156 default "elf64-x86-64" if X86_64
158 config ARCH_DEFCONFIG
160 default "arch/x86/configs/i386_defconfig" if X86_32
161 default "arch/x86/configs/x86_64_defconfig" if X86_64
163 config LOCKDEP_SUPPORT
166 config STACKTRACE_SUPPORT
169 config HAVE_LATENCYTOP_SUPPORT
178 config NEED_DMA_MAP_STATE
180 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
182 config NEED_SG_DMA_LENGTH
185 config GENERIC_ISA_DMA
187 depends on ISA_DMA_API
192 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
194 config GENERIC_BUG_RELATIVE_POINTERS
197 config GENERIC_HWEIGHT
200 config ARCH_MAY_HAVE_PC_FDC
202 depends on ISA_DMA_API
204 config RWSEM_XCHGADD_ALGORITHM
207 config GENERIC_CALIBRATE_DELAY
210 config ARCH_HAS_CPU_RELAX
213 config ARCH_HAS_CACHE_LINE_SIZE
216 config HAVE_SETUP_PER_CPU_AREA
219 config NEED_PER_CPU_EMBED_FIRST_CHUNK
222 config NEED_PER_CPU_PAGE_FIRST_CHUNK
225 config ARCH_HIBERNATION_POSSIBLE
228 config ARCH_SUSPEND_POSSIBLE
231 config ARCH_WANT_HUGE_PMD_SHARE
234 config ARCH_WANT_GENERAL_HUGETLB
245 config ARCH_SUPPORTS_OPTIMIZED_INLINING
248 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
251 config HAVE_INTEL_TXT
253 depends on INTEL_IOMMU && ACPI
257 depends on X86_32 && SMP
261 depends on X86_64 && SMP
267 config X86_32_LAZY_GS
269 depends on X86_32 && !CC_STACKPROTECTOR
271 config ARCH_HWEIGHT_CFLAGS
273 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
274 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
276 config ARCH_SUPPORTS_UPROBES
279 config FIX_EARLYCON_MEM
282 source "init/Kconfig"
283 source "kernel/Kconfig.freezer"
285 menu "Processor type and features"
288 bool "DMA memory allocation support" if EXPERT
291 DMA memory allocation support allows devices with less than 32-bit
292 addressing to allocate within the first 16MB of address space.
293 Disable if no such devices will be used.
298 bool "Symmetric multi-processing support"
300 This enables support for systems with more than one CPU. If you have
301 a system with only one CPU, say N. If you have a system with more
304 If you say N here, the kernel will run on uni- and multiprocessor
305 machines, but will use only one CPU of a multiprocessor machine. If
306 you say Y here, the kernel will run on many, but not all,
307 uniprocessor machines. On a uniprocessor machine, the kernel
308 will run faster if you say N here.
310 Note that if you say Y here and choose architecture "586" or
311 "Pentium" under "Processor family", the kernel will not work on 486
312 architectures. Similarly, multiprocessor kernels for the "PPro"
313 architecture may not work on all Pentium based boards.
315 People using multiprocessor machines who say Y here should also say
316 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
317 Management" code will be disabled if you say Y here.
319 See also <file:Documentation/x86/i386/IO-APIC.txt>,
320 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
321 <http://www.tldp.org/docs.html#howto>.
323 If you don't know what to do here, say N.
325 config X86_FEATURE_NAMES
326 bool "Processor feature human-readable names" if EMBEDDED
329 This option compiles in a table of x86 feature bits and corresponding
330 names. This is required to support /proc/cpuinfo and a few kernel
331 messages. You can disable this to save space, at the expense of
332 making those few kernel messages show numeric feature bits instead.
337 bool "Support x2apic"
338 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
340 This enables x2apic support on CPUs that have this feature.
342 This allows 32-bit apic IDs (so it can support very large systems),
343 and accesses the local apic via MSRs not via mmio.
345 If you don't know what to do here, say N.
348 bool "Enable MPS table" if ACPI || SFI
350 depends on X86_LOCAL_APIC
352 For old smp systems that do not have proper acpi support. Newer systems
353 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
356 bool "Support for big SMP systems with more than 8 CPUs"
357 depends on X86_32 && SMP
359 This option is needed for the systems that have more than 8 CPUs
363 depends on X86_GOLDFISH
366 config X86_EXTENDED_PLATFORM
367 bool "Support for extended (non-PC) x86 platforms"
370 If you disable this option then the kernel will only support
371 standard PC platforms. (which covers the vast majority of
374 If you enable this option then you'll be able to select support
375 for the following (non-PC) 32 bit x86 platforms:
376 Goldfish (Android emulator)
379 SGI 320/540 (Visual Workstation)
380 STA2X11-based (e.g. Northville)
381 Moorestown MID devices
383 If you have one of these systems, or if you want to build a
384 generic distribution kernel, say Y here - otherwise say N.
388 config X86_EXTENDED_PLATFORM
389 bool "Support for extended (non-PC) x86 platforms"
392 If you disable this option then the kernel will only support
393 standard PC platforms. (which covers the vast majority of
396 If you enable this option then you'll be able to select support
397 for the following (non-PC) 64 bit x86 platforms:
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.
405 # This is an alphabetically sorted list of 64 bit extended platforms
406 # Please maintain the alphabetic order if and when there are additions
408 bool "Numascale NumaChip"
410 depends on X86_EXTENDED_PLATFORM
413 depends on X86_X2APIC
414 depends on PCI_MMCONFIG
416 Adds support for Numascale NumaChip large-SMP systems. Needed to
417 enable more than ~168 cores.
418 If you don't have one of these, you should say N here.
422 select HYPERVISOR_GUEST
424 depends on X86_64 && PCI
425 depends on X86_EXTENDED_PLATFORM
428 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
429 supposed to run on these EM64T-based machines. Only choose this option
430 if you have one of these machines.
433 bool "SGI Ultraviolet"
435 depends on X86_EXTENDED_PLATFORM
437 depends on X86_X2APIC
439 This option is needed in order to support SGI Ultraviolet systems.
440 If you don't have one of these, you should say N here.
442 # Following is an alphabetically sorted list of 32 bit extended platforms
443 # Please maintain the alphabetic order if and when there are additions
446 bool "Goldfish (Virtual Platform)"
447 depends on X86_EXTENDED_PLATFORM
449 Enable support for the Goldfish virtual platform used primarily
450 for Android development. Unless you are building for the Android
451 Goldfish emulator say N here.
454 bool "CE4100 TV platform"
456 depends on PCI_GODIRECT
457 depends on X86_IO_APIC
459 depends on X86_EXTENDED_PLATFORM
460 select X86_REBOOTFIXUPS
462 select OF_EARLY_FLATTREE
465 Select for the Intel CE media processor (CE4100) SOC.
466 This option compiles in support for the CE4100 SOC for settop
467 boxes and media devices.
470 bool "Intel MID platform support"
472 depends on X86_EXTENDED_PLATFORM
473 depends on X86_PLATFORM_DEVICES
476 depends on X86_IO_APIC
482 select MFD_INTEL_MSIC
484 Select to build a kernel capable of supporting Intel MID (Mobile
485 Internet Device) platform systems which do not have the PCI legacy
486 interfaces. If you are building for a PC class system say N here.
488 Intel MID platforms are based on an Intel processor and chipset which
489 consume less power than most of the x86 derivatives.
491 config X86_INTEL_LPSS
492 bool "Intel Low Power Subsystem Support"
497 Select to build support for Intel Low Power Subsystem such as
498 found on Intel Lynxpoint PCH. Selecting this option enables
499 things like clock tree (common clock framework) and pincontrol
500 which are needed by the LPSS peripheral drivers.
502 config X86_AMD_PLATFORM_DEVICE
503 bool "AMD ACPI2Platform devices support"
508 Select to interpret AMD specific ACPI device to platform device
509 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
510 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
511 implemented under PINCTRL subsystem.
514 tristate "Intel SoC IOSF Sideband support for SoC platforms"
517 This option enables sideband register access support for Intel SoC
518 platforms. On these platforms the IOSF sideband is used in lieu of
519 MSR's for some register accesses, mostly but not limited to thermal
520 and power. Drivers may query the availability of this device to
521 determine if they need the sideband in order to work on these
522 platforms. The sideband is available on the following SoC products.
523 This list is not meant to be exclusive.
528 You should say Y if you are running a kernel on one of these SoC's.
530 config IOSF_MBI_DEBUG
531 bool "Enable IOSF sideband access through debugfs"
532 depends on IOSF_MBI && DEBUG_FS
534 Select this option to expose the IOSF sideband access registers (MCR,
535 MDR, MCRX) through debugfs to write and read register information from
536 different units on the SoC. This is most useful for obtaining device
537 state information for debug and analysis. As this is a general access
538 mechanism, users of this option would have specific knowledge of the
539 device they want to access.
541 If you don't require the option or are in doubt, say N.
544 bool "RDC R-321x SoC"
546 depends on X86_EXTENDED_PLATFORM
548 select X86_REBOOTFIXUPS
550 This option is needed for RDC R-321x system-on-chip, also known
552 If you don't have one of these chips, you should say N here.
554 config X86_32_NON_STANDARD
555 bool "Support non-standard 32-bit SMP architectures"
556 depends on X86_32 && SMP
557 depends on X86_EXTENDED_PLATFORM
559 This option compiles in the bigsmp and STA2X11 default
560 subarchitectures. It is intended for a generic binary
561 kernel. If you select them all, kernel will probe it one by
562 one and will fallback to default.
564 # Alphabetically sorted list of Non standard 32 bit platforms
566 config X86_SUPPORTS_MEMORY_FAILURE
568 # MCE code calls memory_failure():
570 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
571 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
572 depends on X86_64 || !SPARSEMEM
573 select ARCH_SUPPORTS_MEMORY_FAILURE
576 bool "STA2X11 Companion Chip Support"
577 depends on X86_32_NON_STANDARD && PCI
578 select X86_DEV_DMA_OPS
582 select ARCH_REQUIRE_GPIOLIB
585 This adds support for boards based on the STA2X11 IO-Hub,
586 a.k.a. "ConneXt". The chip is used in place of the standard
587 PC chipset, so all "standard" peripherals are missing. If this
588 option is selected the kernel will still be able to boot on
589 standard PC machines.
592 tristate "Eurobraille/Iris poweroff module"
595 The Iris machines from EuroBraille do not have APM or ACPI support
596 to shut themselves down properly. A special I/O sequence is
597 needed to do so, which is what this module does at
600 This is only for Iris machines from EuroBraille.
604 config SCHED_OMIT_FRAME_POINTER
606 prompt "Single-depth WCHAN output"
609 Calculate simpler /proc/<PID>/wchan values. If this option
610 is disabled then wchan values will recurse back to the
611 caller function. This provides more accurate wchan values,
612 at the expense of slightly more scheduling overhead.
614 If in doubt, say "Y".
616 menuconfig HYPERVISOR_GUEST
617 bool "Linux guest support"
619 Say Y here to enable options for running Linux under various hyper-
620 visors. This option enables basic hypervisor detection and platform
623 If you say N, all options in this submenu will be skipped and
624 disabled, and Linux guest support won't be built in.
629 bool "Enable paravirtualization code"
631 This changes the kernel so it can modify itself when it is run
632 under a hypervisor, potentially improving performance significantly
633 over full virtualization. However, when run without a hypervisor
634 the kernel is theoretically slower and slightly larger.
636 config PARAVIRT_DEBUG
637 bool "paravirt-ops debugging"
638 depends on PARAVIRT && DEBUG_KERNEL
640 Enable to debug paravirt_ops internals. Specifically, BUG if
641 a paravirt_op is missing when it is called.
643 config PARAVIRT_SPINLOCKS
644 bool "Paravirtualization layer for spinlocks"
645 depends on PARAVIRT && SMP
646 select UNINLINE_SPIN_UNLOCK
648 Paravirtualized spinlocks allow a pvops backend to replace the
649 spinlock implementation with something virtualization-friendly
650 (for example, block the virtual CPU rather than spinning).
652 It has a minimal impact on native kernels and gives a nice performance
653 benefit on paravirtualized KVM / Xen kernels.
655 If you are unsure how to answer this question, answer Y.
657 source "arch/x86/xen/Kconfig"
660 bool "KVM Guest support (including kvmclock)"
662 select PARAVIRT_CLOCK
665 This option enables various optimizations for running under the KVM
666 hypervisor. It includes a paravirtualized clock, so that instead
667 of relying on a PIT (or probably other) emulation by the
668 underlying device model, the host provides the guest with
669 timing infrastructure such as time of day, and system time
672 bool "Enable debug information for KVM Guests in debugfs"
673 depends on KVM_GUEST && DEBUG_FS
676 This option enables collection of various statistics for KVM guest.
677 Statistics are displayed in debugfs filesystem. Enabling this option
678 may incur significant overhead.
680 source "arch/x86/lguest/Kconfig"
682 config PARAVIRT_TIME_ACCOUNTING
683 bool "Paravirtual steal time accounting"
687 Select this option to enable fine granularity task steal time
688 accounting. Time spent executing other tasks in parallel with
689 the current vCPU is discounted from the vCPU power. To account for
690 that, there can be a small performance impact.
692 If in doubt, say N here.
694 config PARAVIRT_CLOCK
697 endif #HYPERVISOR_GUEST
705 This option adds a kernel parameter 'memtest', which allows memtest
707 memtest=0, mean disabled; -- default
708 memtest=1, mean do 1 test pattern;
710 memtest=4, mean do 4 test patterns.
711 If you are unsure how to answer this question, answer N.
713 source "arch/x86/Kconfig.cpu"
717 prompt "HPET Timer Support" if X86_32
719 Use the IA-PC HPET (High Precision Event Timer) to manage
720 time in preference to the PIT and RTC, if a HPET is
722 HPET is the next generation timer replacing legacy 8254s.
723 The HPET provides a stable time base on SMP
724 systems, unlike the TSC, but it is more expensive to access,
725 as it is off-chip. You can find the HPET spec at
726 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
728 You can safely choose Y here. However, HPET will only be
729 activated if the platform and the BIOS support this feature.
730 Otherwise the 8254 will be used for timing services.
732 Choose N to continue using the legacy 8254 timer.
734 config HPET_EMULATE_RTC
736 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
739 def_bool y if X86_INTEL_MID
740 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
742 depends on X86_INTEL_MID && SFI
744 APB timer is the replacement for 8254, HPET on X86 MID platforms.
745 The APBT 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. APB timers are always running regardless of CPU
748 C states, they are used as per CPU clockevent device when possible.
750 # Mark as expert because too many people got it wrong.
751 # The code disables itself when not needed.
754 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
755 bool "Enable DMI scanning" if EXPERT
757 Enabled scanning of DMI to identify machine quirks. Say Y
758 here unless you have verified that your setup is not
759 affected by entries in the DMI blacklist. Required by PNP
763 bool "Old AMD GART IOMMU support"
765 depends on X86_64 && PCI && AMD_NB
767 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
768 GART based hardware IOMMUs.
770 The GART supports full DMA access for devices with 32-bit access
771 limitations, on systems with more than 3 GB. This is usually needed
772 for USB, sound, many IDE/SATA chipsets and some other devices.
774 Newer systems typically have a modern AMD IOMMU, supported via
775 the CONFIG_AMD_IOMMU=y config option.
777 In normal configurations this driver is only active when needed:
778 there's more than 3 GB of memory and the system contains a
779 32-bit limited device.
784 bool "IBM Calgary IOMMU support"
786 depends on X86_64 && PCI
788 Support for hardware IOMMUs in IBM's xSeries x366 and x460
789 systems. Needed to run systems with more than 3GB of memory
790 properly with 32-bit PCI devices that do not support DAC
791 (Double Address Cycle). Calgary also supports bus level
792 isolation, where all DMAs pass through the IOMMU. This
793 prevents them from going anywhere except their intended
794 destination. This catches hard-to-find kernel bugs and
795 mis-behaving drivers and devices that do not use the DMA-API
796 properly to set up their DMA buffers. The IOMMU can be
797 turned off at boot time with the iommu=off parameter.
798 Normally the kernel will make the right choice by itself.
801 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
803 prompt "Should Calgary be enabled by default?"
804 depends on CALGARY_IOMMU
806 Should Calgary be enabled by default? if you choose 'y', Calgary
807 will be used (if it exists). If you choose 'n', Calgary will not be
808 used even if it exists. If you choose 'n' and would like to use
809 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
812 # need this always selected by IOMMU for the VIA workaround
816 Support for software bounce buffers used on x86-64 systems
817 which don't have a hardware IOMMU. Using this PCI devices
818 which can only access 32-bits of memory can be used on systems
819 with more than 3 GB of memory.
824 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
827 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
828 depends on X86_64 && SMP && DEBUG_KERNEL
829 select CPUMASK_OFFSTACK
831 Enable maximum number of CPUS and NUMA Nodes for this architecture.
835 int "Maximum number of CPUs" if SMP && !MAXSMP
836 range 2 8 if SMP && X86_32 && !X86_BIGSMP
837 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
838 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
840 default "8192" if MAXSMP
841 default "32" if SMP && X86_BIGSMP
844 This allows you to specify the maximum number of CPUs which this
845 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
846 supported value is 4096, otherwise the maximum value is 512. The
847 minimum value which makes sense is 2.
849 This is purely to save memory - each supported CPU adds
850 approximately eight kilobytes to the kernel image.
853 bool "SMT (Hyperthreading) scheduler support"
856 SMT scheduler support improves the CPU scheduler's decision making
857 when dealing with Intel Pentium 4 chips with HyperThreading at a
858 cost of slightly increased overhead in some places. If unsure say
863 prompt "Multi-core scheduler support"
866 Multi-core scheduler support improves the CPU scheduler's decision
867 making when dealing with multi-core CPU chips at a cost of slightly
868 increased overhead in some places. If unsure say N here.
870 source "kernel/Kconfig.preempt"
874 depends on !SMP && X86_LOCAL_APIC
877 bool "Local APIC support on uniprocessors"
878 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
880 A local APIC (Advanced Programmable Interrupt Controller) is an
881 integrated interrupt controller in the CPU. If you have a single-CPU
882 system which has a processor with a local APIC, you can say Y here to
883 enable and use it. If you say Y here even though your machine doesn't
884 have a local APIC, then the kernel will still run with no slowdown at
885 all. The local APIC supports CPU-generated self-interrupts (timer,
886 performance counters), and the NMI watchdog which detects hard
889 config X86_UP_APIC_MSI
891 select X86_UP_APIC if X86_32 && !SMP && !X86_32_NON_STANDARD && PCI_MSI
894 bool "IO-APIC support on uniprocessors"
895 depends on X86_UP_APIC
897 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
898 SMP-capable replacement for PC-style interrupt controllers. Most
899 SMP systems and many recent uniprocessor systems have one.
901 If you have a single-CPU system with an IO-APIC, you can say Y here
902 to use it. If you say Y here even though your machine doesn't have
903 an IO-APIC, then the kernel will still run with no slowdown at all.
905 config X86_LOCAL_APIC
907 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
908 select GENERIC_IRQ_LEGACY_ALLOC_HWIRQ
911 def_bool X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
912 depends on X86_LOCAL_APIC
915 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
916 bool "Reroute for broken boot IRQs"
917 depends on X86_IO_APIC
919 This option enables a workaround that fixes a source of
920 spurious interrupts. This is recommended when threaded
921 interrupt handling is used on systems where the generation of
922 superfluous "boot interrupts" cannot be disabled.
924 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
925 entry in the chipset's IO-APIC is masked (as, e.g. the RT
926 kernel does during interrupt handling). On chipsets where this
927 boot IRQ generation cannot be disabled, this workaround keeps
928 the original IRQ line masked so that only the equivalent "boot
929 IRQ" is delivered to the CPUs. The workaround also tells the
930 kernel to set up the IRQ handler on the boot IRQ line. In this
931 way only one interrupt is delivered to the kernel. Otherwise
932 the spurious second interrupt may cause the kernel to bring
933 down (vital) interrupt lines.
935 Only affects "broken" chipsets. Interrupt sharing may be
936 increased on these systems.
939 bool "Machine Check / overheating reporting"
942 Machine Check support allows the processor to notify the
943 kernel if it detects a problem (e.g. overheating, data corruption).
944 The action the kernel takes depends on the severity of the problem,
945 ranging from warning messages to halting the machine.
949 prompt "Intel MCE features"
950 depends on X86_MCE && X86_LOCAL_APIC
952 Additional support for intel specific MCE features such as
957 prompt "AMD MCE features"
958 depends on X86_MCE && X86_LOCAL_APIC
960 Additional support for AMD specific MCE features such as
961 the DRAM Error Threshold.
963 config X86_ANCIENT_MCE
964 bool "Support for old Pentium 5 / WinChip machine checks"
965 depends on X86_32 && X86_MCE
967 Include support for machine check handling on old Pentium 5 or WinChip
968 systems. These typically need to be enabled explicitly on the command
971 config X86_MCE_THRESHOLD
972 depends on X86_MCE_AMD || X86_MCE_INTEL
975 config X86_MCE_INJECT
977 tristate "Machine check injector support"
979 Provide support for injecting machine checks for testing purposes.
980 If you don't know what a machine check is and you don't do kernel
981 QA it is safe to say n.
983 config X86_THERMAL_VECTOR
985 depends on X86_MCE_INTEL
988 bool "Enable VM86 support" if EXPERT
992 This option is required by programs like DOSEMU to run
993 16-bit real mode legacy code on x86 processors. It also may
994 be needed by software like XFree86 to initialize some video
995 cards via BIOS. Disabling this option saves about 6K.
998 bool "Enable support for 16-bit segments" if EXPERT
1001 This option is required by programs like Wine to run 16-bit
1002 protected mode legacy code on x86 processors. Disabling
1003 this option saves about 300 bytes on i386, or around 6K text
1004 plus 16K runtime memory on x86-64,
1008 depends on X86_16BIT && X86_32
1012 depends on X86_16BIT && X86_64
1014 config X86_VSYSCALL_EMULATION
1015 bool "Enable vsyscall emulation" if EXPERT
1019 This enables emulation of the legacy vsyscall page. Disabling
1020 it is roughly equivalent to booting with vsyscall=none, except
1021 that it will also disable the helpful warning if a program
1022 tries to use a vsyscall. With this option set to N, offending
1023 programs will just segfault, citing addresses of the form
1026 This option is required by many programs built before 2013, and
1027 care should be used even with newer programs if set to N.
1029 Disabling this option saves about 7K of kernel size and
1030 possibly 4K of additional runtime pagetable memory.
1033 tristate "Toshiba Laptop support"
1036 This adds a driver to safely access the System Management Mode of
1037 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1038 not work on models with a Phoenix BIOS. The System Management Mode
1039 is used to set the BIOS and power saving options on Toshiba portables.
1041 For information on utilities to make use of this driver see the
1042 Toshiba Linux utilities web site at:
1043 <http://www.buzzard.org.uk/toshiba/>.
1045 Say Y if you intend to run this kernel on a Toshiba portable.
1049 tristate "Dell laptop support"
1052 This adds a driver to safely access the System Management Mode
1053 of the CPU on the Dell Inspiron 8000. The System Management Mode
1054 is used to read cpu temperature and cooling fan status and to
1055 control the fans on the I8K portables.
1057 This driver has been tested only on the Inspiron 8000 but it may
1058 also work with other Dell laptops. You can force loading on other
1059 models by passing the parameter `force=1' to the module. Use at
1062 For information on utilities to make use of this driver see the
1063 I8K Linux utilities web site at:
1064 <http://people.debian.org/~dz/i8k/>
1066 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
1069 config X86_REBOOTFIXUPS
1070 bool "Enable X86 board specific fixups for reboot"
1073 This enables chipset and/or board specific fixups to be done
1074 in order to get reboot to work correctly. This is only needed on
1075 some combinations of hardware and BIOS. The symptom, for which
1076 this config is intended, is when reboot ends with a stalled/hung
1079 Currently, the only fixup is for the Geode machines using
1080 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1082 Say Y if you want to enable the fixup. Currently, it's safe to
1083 enable this option even if you don't need it.
1087 tristate "CPU microcode loading support"
1088 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1092 If you say Y here, you will be able to update the microcode on
1093 certain Intel and AMD processors. The Intel support is for the
1094 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1095 Xeon etc. The AMD support is for families 0x10 and later. You will
1096 obviously need the actual microcode binary data itself which is not
1097 shipped with the Linux kernel.
1099 This option selects the general module only, you need to select
1100 at least one vendor specific module as well.
1102 To compile this driver as a module, choose M here: the module
1103 will be called microcode.
1105 config MICROCODE_INTEL
1106 bool "Intel microcode loading support"
1107 depends on MICROCODE
1111 This options enables microcode patch loading support for Intel
1114 For the current Intel microcode data package go to
1115 <https://downloadcenter.intel.com> and search for
1116 'Linux Processor Microcode Data File'.
1118 config MICROCODE_AMD
1119 bool "AMD microcode loading support"
1120 depends on MICROCODE
1123 If you select this option, microcode patch loading support for AMD
1124 processors will be enabled.
1126 config MICROCODE_OLD_INTERFACE
1128 depends on MICROCODE
1130 config MICROCODE_INTEL_EARLY
1133 config MICROCODE_AMD_EARLY
1136 config MICROCODE_EARLY
1137 bool "Early load microcode"
1138 depends on MICROCODE=y && BLK_DEV_INITRD
1139 select MICROCODE_INTEL_EARLY if MICROCODE_INTEL
1140 select MICROCODE_AMD_EARLY if MICROCODE_AMD
1143 This option provides functionality to read additional microcode data
1144 at the beginning of initrd image. The data tells kernel to load
1145 microcode to CPU's as early as possible. No functional change if no
1146 microcode data is glued to the initrd, therefore it's safe to say Y.
1149 tristate "/dev/cpu/*/msr - Model-specific register support"
1151 This device gives privileged processes access to the x86
1152 Model-Specific Registers (MSRs). It is a character device with
1153 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1154 MSR accesses are directed to a specific CPU on multi-processor
1158 tristate "/dev/cpu/*/cpuid - CPU information support"
1160 This device gives processes access to the x86 CPUID instruction to
1161 be executed on a specific processor. It is a character device
1162 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1166 prompt "High Memory Support"
1173 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1174 However, the address space of 32-bit x86 processors is only 4
1175 Gigabytes large. That means that, if you have a large amount of
1176 physical memory, not all of it can be "permanently mapped" by the
1177 kernel. The physical memory that's not permanently mapped is called
1180 If you are compiling a kernel which will never run on a machine with
1181 more than 1 Gigabyte total physical RAM, answer "off" here (default
1182 choice and suitable for most users). This will result in a "3GB/1GB"
1183 split: 3GB are mapped so that each process sees a 3GB virtual memory
1184 space and the remaining part of the 4GB virtual memory space is used
1185 by the kernel to permanently map as much physical memory as
1188 If the machine has between 1 and 4 Gigabytes physical RAM, then
1191 If more than 4 Gigabytes is used then answer "64GB" here. This
1192 selection turns Intel PAE (Physical Address Extension) mode on.
1193 PAE implements 3-level paging on IA32 processors. PAE is fully
1194 supported by Linux, PAE mode is implemented on all recent Intel
1195 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1196 then the kernel will not boot on CPUs that don't support PAE!
1198 The actual amount of total physical memory will either be
1199 auto detected or can be forced by using a kernel command line option
1200 such as "mem=256M". (Try "man bootparam" or see the documentation of
1201 your boot loader (lilo or loadlin) about how to pass options to the
1202 kernel at boot time.)
1204 If unsure, say "off".
1209 Select this if you have a 32-bit processor and between 1 and 4
1210 gigabytes of physical RAM.
1217 Select this if you have a 32-bit processor and more than 4
1218 gigabytes of physical RAM.
1223 prompt "Memory split" if EXPERT
1227 Select the desired split between kernel and user memory.
1229 If the address range available to the kernel is less than the
1230 physical memory installed, the remaining memory will be available
1231 as "high memory". Accessing high memory is a little more costly
1232 than low memory, as it needs to be mapped into the kernel first.
1233 Note that increasing the kernel address space limits the range
1234 available to user programs, making the address space there
1235 tighter. Selecting anything other than the default 3G/1G split
1236 will also likely make your kernel incompatible with binary-only
1239 If you are not absolutely sure what you are doing, leave this
1243 bool "3G/1G user/kernel split"
1244 config VMSPLIT_3G_OPT
1246 bool "3G/1G user/kernel split (for full 1G low memory)"
1248 bool "2G/2G user/kernel split"
1249 config VMSPLIT_2G_OPT
1251 bool "2G/2G user/kernel split (for full 2G low memory)"
1253 bool "1G/3G user/kernel split"
1258 default 0xB0000000 if VMSPLIT_3G_OPT
1259 default 0x80000000 if VMSPLIT_2G
1260 default 0x78000000 if VMSPLIT_2G_OPT
1261 default 0x40000000 if VMSPLIT_1G
1267 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1270 bool "PAE (Physical Address Extension) Support"
1271 depends on X86_32 && !HIGHMEM4G
1273 PAE is required for NX support, and furthermore enables
1274 larger swapspace support for non-overcommit purposes. It
1275 has the cost of more pagetable lookup overhead, and also
1276 consumes more pagetable space per process.
1278 config ARCH_PHYS_ADDR_T_64BIT
1280 depends on X86_64 || X86_PAE
1282 config ARCH_DMA_ADDR_T_64BIT
1284 depends on X86_64 || HIGHMEM64G
1286 config DIRECT_GBPAGES
1287 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1291 Allow the kernel linear mapping to use 1GB pages on CPUs that
1292 support it. This can improve the kernel's performance a tiny bit by
1293 reducing TLB pressure. If in doubt, say "Y".
1295 # Common NUMA Features
1297 bool "Numa Memory Allocation and Scheduler Support"
1299 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1300 default y if X86_BIGSMP
1302 Enable NUMA (Non Uniform Memory Access) support.
1304 The kernel will try to allocate memory used by a CPU on the
1305 local memory controller of the CPU and add some more
1306 NUMA awareness to the kernel.
1308 For 64-bit this is recommended if the system is Intel Core i7
1309 (or later), AMD Opteron, or EM64T NUMA.
1311 For 32-bit this is only needed if you boot a 32-bit
1312 kernel on a 64-bit NUMA platform.
1314 Otherwise, you should say N.
1318 prompt "Old style AMD Opteron NUMA detection"
1319 depends on X86_64 && NUMA && PCI
1321 Enable AMD NUMA node topology detection. You should say Y here if
1322 you have a multi processor AMD system. This uses an old method to
1323 read the NUMA configuration directly from the builtin Northbridge
1324 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1325 which also takes priority if both are compiled in.
1327 config X86_64_ACPI_NUMA
1329 prompt "ACPI NUMA detection"
1330 depends on X86_64 && NUMA && ACPI && PCI
1333 Enable ACPI SRAT based node topology detection.
1335 # Some NUMA nodes have memory ranges that span
1336 # other nodes. Even though a pfn is valid and
1337 # between a node's start and end pfns, it may not
1338 # reside on that node. See memmap_init_zone()
1340 config NODES_SPAN_OTHER_NODES
1342 depends on X86_64_ACPI_NUMA
1345 bool "NUMA emulation"
1348 Enable NUMA emulation. A flat machine will be split
1349 into virtual nodes when booted with "numa=fake=N", where N is the
1350 number of nodes. This is only useful for debugging.
1353 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1355 default "10" if MAXSMP
1356 default "6" if X86_64
1358 depends on NEED_MULTIPLE_NODES
1360 Specify the maximum number of NUMA Nodes available on the target
1361 system. Increases memory reserved to accommodate various tables.
1363 config ARCH_HAVE_MEMORY_PRESENT
1365 depends on X86_32 && DISCONTIGMEM
1367 config NEED_NODE_MEMMAP_SIZE
1369 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1371 config ARCH_FLATMEM_ENABLE
1373 depends on X86_32 && !NUMA
1375 config ARCH_DISCONTIGMEM_ENABLE
1377 depends on NUMA && X86_32
1379 config ARCH_DISCONTIGMEM_DEFAULT
1381 depends on NUMA && X86_32
1383 config ARCH_SPARSEMEM_ENABLE
1385 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1386 select SPARSEMEM_STATIC if X86_32
1387 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1389 config ARCH_SPARSEMEM_DEFAULT
1393 config ARCH_SELECT_MEMORY_MODEL
1395 depends on ARCH_SPARSEMEM_ENABLE
1397 config ARCH_MEMORY_PROBE
1398 bool "Enable sysfs memory/probe interface"
1399 depends on X86_64 && MEMORY_HOTPLUG
1401 This option enables a sysfs memory/probe interface for testing.
1402 See Documentation/memory-hotplug.txt for more information.
1403 If you are unsure how to answer this question, answer N.
1405 config ARCH_PROC_KCORE_TEXT
1407 depends on X86_64 && PROC_KCORE
1409 config ILLEGAL_POINTER_VALUE
1412 default 0xdead000000000000 if X86_64
1417 bool "Allocate 3rd-level pagetables from highmem"
1420 The VM uses one page table entry for each page of physical memory.
1421 For systems with a lot of RAM, this can be wasteful of precious
1422 low memory. Setting this option will put user-space page table
1423 entries in high memory.
1425 config X86_CHECK_BIOS_CORRUPTION
1426 bool "Check for low memory corruption"
1428 Periodically check for memory corruption in low memory, which
1429 is suspected to be caused by BIOS. Even when enabled in the
1430 configuration, it is disabled at runtime. Enable it by
1431 setting "memory_corruption_check=1" on the kernel command
1432 line. By default it scans the low 64k of memory every 60
1433 seconds; see the memory_corruption_check_size and
1434 memory_corruption_check_period parameters in
1435 Documentation/kernel-parameters.txt to adjust this.
1437 When enabled with the default parameters, this option has
1438 almost no overhead, as it reserves a relatively small amount
1439 of memory and scans it infrequently. It both detects corruption
1440 and prevents it from affecting the running system.
1442 It is, however, intended as a diagnostic tool; if repeatable
1443 BIOS-originated corruption always affects the same memory,
1444 you can use memmap= to prevent the kernel from using that
1447 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1448 bool "Set the default setting of memory_corruption_check"
1449 depends on X86_CHECK_BIOS_CORRUPTION
1452 Set whether the default state of memory_corruption_check is
1455 config X86_RESERVE_LOW
1456 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1460 Specify the amount of low memory to reserve for the BIOS.
1462 The first page contains BIOS data structures that the kernel
1463 must not use, so that page must always be reserved.
1465 By default we reserve the first 64K of physical RAM, as a
1466 number of BIOSes are known to corrupt that memory range
1467 during events such as suspend/resume or monitor cable
1468 insertion, so it must not be used by the kernel.
1470 You can set this to 4 if you are absolutely sure that you
1471 trust the BIOS to get all its memory reservations and usages
1472 right. If you know your BIOS have problems beyond the
1473 default 64K area, you can set this to 640 to avoid using the
1474 entire low memory range.
1476 If you have doubts about the BIOS (e.g. suspend/resume does
1477 not work or there's kernel crashes after certain hardware
1478 hotplug events) then you might want to enable
1479 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1480 typical corruption patterns.
1482 Leave this to the default value of 64 if you are unsure.
1484 config MATH_EMULATION
1486 prompt "Math emulation" if X86_32
1488 Linux can emulate a math coprocessor (used for floating point
1489 operations) if you don't have one. 486DX and Pentium processors have
1490 a math coprocessor built in, 486SX and 386 do not, unless you added
1491 a 487DX or 387, respectively. (The messages during boot time can
1492 give you some hints here ["man dmesg"].) Everyone needs either a
1493 coprocessor or this emulation.
1495 If you don't have a math coprocessor, you need to say Y here; if you
1496 say Y here even though you have a coprocessor, the coprocessor will
1497 be used nevertheless. (This behavior can be changed with the kernel
1498 command line option "no387", which comes handy if your coprocessor
1499 is broken. Try "man bootparam" or see the documentation of your boot
1500 loader (lilo or loadlin) about how to pass options to the kernel at
1501 boot time.) This means that it is a good idea to say Y here if you
1502 intend to use this kernel on different machines.
1504 More information about the internals of the Linux math coprocessor
1505 emulation can be found in <file:arch/x86/math-emu/README>.
1507 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1508 kernel, it won't hurt.
1512 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1514 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1515 the Memory Type Range Registers (MTRRs) may be used to control
1516 processor access to memory ranges. This is most useful if you have
1517 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1518 allows bus write transfers to be combined into a larger transfer
1519 before bursting over the PCI/AGP bus. This can increase performance
1520 of image write operations 2.5 times or more. Saying Y here creates a
1521 /proc/mtrr file which may be used to manipulate your processor's
1522 MTRRs. Typically the X server should use this.
1524 This code has a reasonably generic interface so that similar
1525 control registers on other processors can be easily supported
1528 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1529 Registers (ARRs) which provide a similar functionality to MTRRs. For
1530 these, the ARRs are used to emulate the MTRRs.
1531 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1532 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1533 write-combining. All of these processors are supported by this code
1534 and it makes sense to say Y here if you have one of them.
1536 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1537 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1538 can lead to all sorts of problems, so it's good to say Y here.
1540 You can safely say Y even if your machine doesn't have MTRRs, you'll
1541 just add about 9 KB to your kernel.
1543 See <file:Documentation/x86/mtrr.txt> for more information.
1545 config MTRR_SANITIZER
1547 prompt "MTRR cleanup support"
1550 Convert MTRR layout from continuous to discrete, so X drivers can
1551 add writeback entries.
1553 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1554 The largest mtrr entry size for a continuous block can be set with
1559 config MTRR_SANITIZER_ENABLE_DEFAULT
1560 int "MTRR cleanup enable value (0-1)"
1563 depends on MTRR_SANITIZER
1565 Enable mtrr cleanup default value
1567 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1568 int "MTRR cleanup spare reg num (0-7)"
1571 depends on MTRR_SANITIZER
1573 mtrr cleanup spare entries default, it can be changed via
1574 mtrr_spare_reg_nr=N on the kernel command line.
1578 prompt "x86 PAT support" if EXPERT
1581 Use PAT attributes to setup page level cache control.
1583 PATs are the modern equivalents of MTRRs and are much more
1584 flexible than MTRRs.
1586 Say N here if you see bootup problems (boot crash, boot hang,
1587 spontaneous reboots) or a non-working video driver.
1591 config ARCH_USES_PG_UNCACHED
1597 prompt "x86 architectural random number generator" if EXPERT
1599 Enable the x86 architectural RDRAND instruction
1600 (Intel Bull Mountain technology) to generate random numbers.
1601 If supported, this is a high bandwidth, cryptographically
1602 secure hardware random number generator.
1606 prompt "Supervisor Mode Access Prevention" if EXPERT
1608 Supervisor Mode Access Prevention (SMAP) is a security
1609 feature in newer Intel processors. There is a small
1610 performance cost if this enabled and turned on; there is
1611 also a small increase in the kernel size if this is enabled.
1615 config X86_INTEL_MPX
1616 prompt "Intel MPX (Memory Protection Extensions)"
1618 depends on CPU_SUP_INTEL
1620 MPX provides hardware features that can be used in
1621 conjunction with compiler-instrumented code to check
1622 memory references. It is designed to detect buffer
1623 overflow or underflow bugs.
1625 This option enables running applications which are
1626 instrumented or otherwise use MPX. It does not use MPX
1627 itself inside the kernel or to protect the kernel
1628 against bad memory references.
1630 Enabling this option will make the kernel larger:
1631 ~8k of kernel text and 36 bytes of data on a 64-bit
1632 defconfig. It adds a long to the 'mm_struct' which
1633 will increase the kernel memory overhead of each
1634 process and adds some branches to paths used during
1635 exec() and munmap().
1637 For details, see Documentation/x86/intel_mpx.txt
1642 bool "EFI runtime service support"
1645 select EFI_RUNTIME_WRAPPERS
1647 This enables the kernel to use EFI runtime services that are
1648 available (such as the EFI variable services).
1650 This option is only useful on systems that have EFI firmware.
1651 In addition, you should use the latest ELILO loader available
1652 at <http://elilo.sourceforge.net> in order to take advantage
1653 of EFI runtime services. However, even with this option, the
1654 resultant kernel should continue to boot on existing non-EFI
1658 bool "EFI stub support"
1659 depends on EFI && !X86_USE_3DNOW
1662 This kernel feature allows a bzImage to be loaded directly
1663 by EFI firmware without the use of a bootloader.
1665 See Documentation/efi-stub.txt for more information.
1668 bool "EFI mixed-mode support"
1669 depends on EFI_STUB && X86_64
1671 Enabling this feature allows a 64-bit kernel to be booted
1672 on a 32-bit firmware, provided that your CPU supports 64-bit
1675 Note that it is not possible to boot a mixed-mode enabled
1676 kernel via the EFI boot stub - a bootloader that supports
1677 the EFI handover protocol must be used.
1683 prompt "Enable seccomp to safely compute untrusted bytecode"
1685 This kernel feature is useful for number crunching applications
1686 that may need to compute untrusted bytecode during their
1687 execution. By using pipes or other transports made available to
1688 the process as file descriptors supporting the read/write
1689 syscalls, it's possible to isolate those applications in
1690 their own address space using seccomp. Once seccomp is
1691 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1692 and the task is only allowed to execute a few safe syscalls
1693 defined by each seccomp mode.
1695 If unsure, say Y. Only embedded should say N here.
1697 source kernel/Kconfig.hz
1700 bool "kexec system call"
1702 kexec is a system call that implements the ability to shutdown your
1703 current kernel, and to start another kernel. It is like a reboot
1704 but it is independent of the system firmware. And like a reboot
1705 you can start any kernel with it, not just Linux.
1707 The name comes from the similarity to the exec system call.
1709 It is an ongoing process to be certain the hardware in a machine
1710 is properly shutdown, so do not be surprised if this code does not
1711 initially work for you. As of this writing the exact hardware
1712 interface is strongly in flux, so no good recommendation can be
1716 bool "kexec file based system call"
1721 depends on CRYPTO_SHA256=y
1723 This is new version of kexec system call. This system call is
1724 file based and takes file descriptors as system call argument
1725 for kernel and initramfs as opposed to list of segments as
1726 accepted by previous system call.
1728 config KEXEC_VERIFY_SIG
1729 bool "Verify kernel signature during kexec_file_load() syscall"
1730 depends on KEXEC_FILE
1732 This option makes kernel signature verification mandatory for
1733 kexec_file_load() syscall. If kernel is signature can not be
1734 verified, kexec_file_load() will fail.
1736 This option enforces signature verification at generic level.
1737 One needs to enable signature verification for type of kernel
1738 image being loaded to make sure it works. For example, enable
1739 bzImage signature verification option to be able to load and
1740 verify signatures of bzImage. Otherwise kernel loading will fail.
1742 config KEXEC_BZIMAGE_VERIFY_SIG
1743 bool "Enable bzImage signature verification support"
1744 depends on KEXEC_VERIFY_SIG
1745 depends on SIGNED_PE_FILE_VERIFICATION
1746 select SYSTEM_TRUSTED_KEYRING
1748 Enable bzImage signature verification support.
1751 bool "kernel crash dumps"
1752 depends on X86_64 || (X86_32 && HIGHMEM)
1754 Generate crash dump after being started by kexec.
1755 This should be normally only set in special crash dump kernels
1756 which are loaded in the main kernel with kexec-tools into
1757 a specially reserved region and then later executed after
1758 a crash by kdump/kexec. The crash dump kernel must be compiled
1759 to a memory address not used by the main kernel or BIOS using
1760 PHYSICAL_START, or it must be built as a relocatable image
1761 (CONFIG_RELOCATABLE=y).
1762 For more details see Documentation/kdump/kdump.txt
1766 depends on KEXEC && HIBERNATION
1768 Jump between original kernel and kexeced kernel and invoke
1769 code in physical address mode via KEXEC
1771 config PHYSICAL_START
1772 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1775 This gives the physical address where the kernel is loaded.
1777 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1778 bzImage will decompress itself to above physical address and
1779 run from there. Otherwise, bzImage will run from the address where
1780 it has been loaded by the boot loader and will ignore above physical
1783 In normal kdump cases one does not have to set/change this option
1784 as now bzImage can be compiled as a completely relocatable image
1785 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1786 address. This option is mainly useful for the folks who don't want
1787 to use a bzImage for capturing the crash dump and want to use a
1788 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1789 to be specifically compiled to run from a specific memory area
1790 (normally a reserved region) and this option comes handy.
1792 So if you are using bzImage for capturing the crash dump,
1793 leave the value here unchanged to 0x1000000 and set
1794 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1795 for capturing the crash dump change this value to start of
1796 the reserved region. In other words, it can be set based on
1797 the "X" value as specified in the "crashkernel=YM@XM"
1798 command line boot parameter passed to the panic-ed
1799 kernel. Please take a look at Documentation/kdump/kdump.txt
1800 for more details about crash dumps.
1802 Usage of bzImage for capturing the crash dump is recommended as
1803 one does not have to build two kernels. Same kernel can be used
1804 as production kernel and capture kernel. Above option should have
1805 gone away after relocatable bzImage support is introduced. But it
1806 is present because there are users out there who continue to use
1807 vmlinux for dump capture. This option should go away down the
1810 Don't change this unless you know what you are doing.
1813 bool "Build a relocatable kernel"
1816 This builds a kernel image that retains relocation information
1817 so it can be loaded someplace besides the default 1MB.
1818 The relocations tend to make the kernel binary about 10% larger,
1819 but are discarded at runtime.
1821 One use is for the kexec on panic case where the recovery kernel
1822 must live at a different physical address than the primary
1825 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1826 it has been loaded at and the compile time physical address
1827 (CONFIG_PHYSICAL_START) is used as the minimum location.
1829 config RANDOMIZE_BASE
1830 bool "Randomize the address of the kernel image"
1831 depends on RELOCATABLE
1834 Randomizes the physical and virtual address at which the
1835 kernel image is decompressed, as a security feature that
1836 deters exploit attempts relying on knowledge of the location
1837 of kernel internals.
1839 Entropy is generated using the RDRAND instruction if it is
1840 supported. If RDTSC is supported, it is used as well. If
1841 neither RDRAND nor RDTSC are supported, then randomness is
1842 read from the i8254 timer.
1844 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1845 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1846 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1847 minimum of 2MiB, only 10 bits of entropy is theoretically
1848 possible. At best, due to page table layouts, 64-bit can use
1849 9 bits of entropy and 32-bit uses 8 bits.
1853 config RANDOMIZE_BASE_MAX_OFFSET
1854 hex "Maximum kASLR offset allowed" if EXPERT
1855 depends on RANDOMIZE_BASE
1856 range 0x0 0x20000000 if X86_32
1857 default "0x20000000" if X86_32
1858 range 0x0 0x40000000 if X86_64
1859 default "0x40000000" if X86_64
1861 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1862 memory is used to determine the maximal offset in bytes that will
1863 be applied to the kernel when kernel Address Space Layout
1864 Randomization (kASLR) is active. This must be a multiple of
1867 On 32-bit this is limited to 512MiB by page table layouts. The
1870 On 64-bit this is limited by how the kernel fixmap page table is
1871 positioned, so this cannot be larger than 1GiB currently. Without
1872 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1873 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1874 modules area will shrink to compensate, up to the current maximum
1875 1GiB to 1GiB split. The default is 1GiB.
1877 If unsure, leave at the default value.
1879 # Relocation on x86 needs some additional build support
1880 config X86_NEED_RELOCS
1882 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1884 config PHYSICAL_ALIGN
1885 hex "Alignment value to which kernel should be aligned"
1887 range 0x2000 0x1000000 if X86_32
1888 range 0x200000 0x1000000 if X86_64
1890 This value puts the alignment restrictions on physical address
1891 where kernel is loaded and run from. Kernel is compiled for an
1892 address which meets above alignment restriction.
1894 If bootloader loads the kernel at a non-aligned address and
1895 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1896 address aligned to above value and run from there.
1898 If bootloader loads the kernel at a non-aligned address and
1899 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1900 load address and decompress itself to the address it has been
1901 compiled for and run from there. The address for which kernel is
1902 compiled already meets above alignment restrictions. Hence the
1903 end result is that kernel runs from a physical address meeting
1904 above alignment restrictions.
1906 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1907 this value must be a multiple of 0x200000.
1909 Don't change this unless you know what you are doing.
1912 bool "Support for hot-pluggable CPUs"
1915 Say Y here to allow turning CPUs off and on. CPUs can be
1916 controlled through /sys/devices/system/cpu.
1917 ( Note: power management support will enable this option
1918 automatically on SMP systems. )
1919 Say N if you want to disable CPU hotplug.
1921 config BOOTPARAM_HOTPLUG_CPU0
1922 bool "Set default setting of cpu0_hotpluggable"
1924 depends on HOTPLUG_CPU
1926 Set whether default state of cpu0_hotpluggable is on or off.
1928 Say Y here to enable CPU0 hotplug by default. If this switch
1929 is turned on, there is no need to give cpu0_hotplug kernel
1930 parameter and the CPU0 hotplug feature is enabled by default.
1932 Please note: there are two known CPU0 dependencies if you want
1933 to enable the CPU0 hotplug feature either by this switch or by
1934 cpu0_hotplug kernel parameter.
1936 First, resume from hibernate or suspend always starts from CPU0.
1937 So hibernate and suspend are prevented if CPU0 is offline.
1939 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1940 offline if any interrupt can not migrate out of CPU0. There may
1941 be other CPU0 dependencies.
1943 Please make sure the dependencies are under your control before
1944 you enable this feature.
1946 Say N if you don't want to enable CPU0 hotplug feature by default.
1947 You still can enable the CPU0 hotplug feature at boot by kernel
1948 parameter cpu0_hotplug.
1950 config DEBUG_HOTPLUG_CPU0
1952 prompt "Debug CPU0 hotplug"
1953 depends on HOTPLUG_CPU
1955 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1956 soon as possible and boots up userspace with CPU0 offlined. User
1957 can online CPU0 back after boot time.
1959 To debug CPU0 hotplug, you need to enable CPU0 offline/online
1960 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1961 compilation or giving cpu0_hotplug kernel parameter at boot.
1967 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
1968 depends on X86_32 || IA32_EMULATION
1970 Certain buggy versions of glibc will crash if they are
1971 presented with a 32-bit vDSO that is not mapped at the address
1972 indicated in its segment table.
1974 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
1975 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
1976 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
1977 the only released version with the bug, but OpenSUSE 9
1978 contains a buggy "glibc 2.3.2".
1980 The symptom of the bug is that everything crashes on startup, saying:
1981 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
1983 Saying Y here changes the default value of the vdso32 boot
1984 option from 1 to 0, which turns off the 32-bit vDSO entirely.
1985 This works around the glibc bug but hurts performance.
1987 If unsure, say N: if you are compiling your own kernel, you
1988 are unlikely to be using a buggy version of glibc.
1991 bool "Built-in kernel command line"
1993 Allow for specifying boot arguments to the kernel at
1994 build time. On some systems (e.g. embedded ones), it is
1995 necessary or convenient to provide some or all of the
1996 kernel boot arguments with the kernel itself (that is,
1997 to not rely on the boot loader to provide them.)
1999 To compile command line arguments into the kernel,
2000 set this option to 'Y', then fill in the
2001 the boot arguments in CONFIG_CMDLINE.
2003 Systems with fully functional boot loaders (i.e. non-embedded)
2004 should leave this option set to 'N'.
2007 string "Built-in kernel command string"
2008 depends on CMDLINE_BOOL
2011 Enter arguments here that should be compiled into the kernel
2012 image and used at boot time. If the boot loader provides a
2013 command line at boot time, it is appended to this string to
2014 form the full kernel command line, when the system boots.
2016 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2017 change this behavior.
2019 In most cases, the command line (whether built-in or provided
2020 by the boot loader) should specify the device for the root
2023 config CMDLINE_OVERRIDE
2024 bool "Built-in command line overrides boot loader arguments"
2025 depends on CMDLINE_BOOL
2027 Set this option to 'Y' to have the kernel ignore the boot loader
2028 command line, and use ONLY the built-in command line.
2030 This is used to work around broken boot loaders. This should
2031 be set to 'N' under normal conditions.
2033 source "kernel/livepatch/Kconfig"
2037 config ARCH_ENABLE_MEMORY_HOTPLUG
2039 depends on X86_64 || (X86_32 && HIGHMEM)
2041 config ARCH_ENABLE_MEMORY_HOTREMOVE
2043 depends on MEMORY_HOTPLUG
2045 config USE_PERCPU_NUMA_NODE_ID
2049 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2051 depends on X86_64 || X86_PAE
2053 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2055 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2057 menu "Power management and ACPI options"
2059 config ARCH_HIBERNATION_HEADER
2061 depends on X86_64 && HIBERNATION
2063 source "kernel/power/Kconfig"
2065 source "drivers/acpi/Kconfig"
2067 source "drivers/sfi/Kconfig"
2074 tristate "APM (Advanced Power Management) BIOS support"
2075 depends on X86_32 && PM_SLEEP
2077 APM is a BIOS specification for saving power using several different
2078 techniques. This is mostly useful for battery powered laptops with
2079 APM compliant BIOSes. If you say Y here, the system time will be
2080 reset after a RESUME operation, the /proc/apm device will provide
2081 battery status information, and user-space programs will receive
2082 notification of APM "events" (e.g. battery status change).
2084 If you select "Y" here, you can disable actual use of the APM
2085 BIOS by passing the "apm=off" option to the kernel at boot time.
2087 Note that the APM support is almost completely disabled for
2088 machines with more than one CPU.
2090 In order to use APM, you will need supporting software. For location
2091 and more information, read <file:Documentation/power/apm-acpi.txt>
2092 and the Battery Powered Linux mini-HOWTO, available from
2093 <http://www.tldp.org/docs.html#howto>.
2095 This driver does not spin down disk drives (see the hdparm(8)
2096 manpage ("man 8 hdparm") for that), and it doesn't turn off
2097 VESA-compliant "green" monitors.
2099 This driver does not support the TI 4000M TravelMate and the ACER
2100 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2101 desktop machines also don't have compliant BIOSes, and this driver
2102 may cause those machines to panic during the boot phase.
2104 Generally, if you don't have a battery in your machine, there isn't
2105 much point in using this driver and you should say N. If you get
2106 random kernel OOPSes or reboots that don't seem to be related to
2107 anything, try disabling/enabling this option (or disabling/enabling
2110 Some other things you should try when experiencing seemingly random,
2113 1) make sure that you have enough swap space and that it is
2115 2) pass the "no-hlt" option to the kernel
2116 3) switch on floating point emulation in the kernel and pass
2117 the "no387" option to the kernel
2118 4) pass the "floppy=nodma" option to the kernel
2119 5) pass the "mem=4M" option to the kernel (thereby disabling
2120 all but the first 4 MB of RAM)
2121 6) make sure that the CPU is not over clocked.
2122 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2123 8) disable the cache from your BIOS settings
2124 9) install a fan for the video card or exchange video RAM
2125 10) install a better fan for the CPU
2126 11) exchange RAM chips
2127 12) exchange the motherboard.
2129 To compile this driver as a module, choose M here: the
2130 module will be called apm.
2134 config APM_IGNORE_USER_SUSPEND
2135 bool "Ignore USER SUSPEND"
2137 This option will ignore USER SUSPEND requests. On machines with a
2138 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2139 series notebooks, it is necessary to say Y because of a BIOS bug.
2141 config APM_DO_ENABLE
2142 bool "Enable PM at boot time"
2144 Enable APM features at boot time. From page 36 of the APM BIOS
2145 specification: "When disabled, the APM BIOS does not automatically
2146 power manage devices, enter the Standby State, enter the Suspend
2147 State, or take power saving steps in response to CPU Idle calls."
2148 This driver will make CPU Idle calls when Linux is idle (unless this
2149 feature is turned off -- see "Do CPU IDLE calls", below). This
2150 should always save battery power, but more complicated APM features
2151 will be dependent on your BIOS implementation. You may need to turn
2152 this option off if your computer hangs at boot time when using APM
2153 support, or if it beeps continuously instead of suspending. Turn
2154 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2155 T400CDT. This is off by default since most machines do fine without
2160 bool "Make CPU Idle calls when idle"
2162 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2163 On some machines, this can activate improved power savings, such as
2164 a slowed CPU clock rate, when the machine is idle. These idle calls
2165 are made after the idle loop has run for some length of time (e.g.,
2166 333 mS). On some machines, this will cause a hang at boot time or
2167 whenever the CPU becomes idle. (On machines with more than one CPU,
2168 this option does nothing.)
2170 config APM_DISPLAY_BLANK
2171 bool "Enable console blanking using APM"
2173 Enable console blanking using the APM. Some laptops can use this to
2174 turn off the LCD backlight when the screen blanker of the Linux
2175 virtual console blanks the screen. Note that this is only used by
2176 the virtual console screen blanker, and won't turn off the backlight
2177 when using the X Window system. This also doesn't have anything to
2178 do with your VESA-compliant power-saving monitor. Further, this
2179 option doesn't work for all laptops -- it might not turn off your
2180 backlight at all, or it might print a lot of errors to the console,
2181 especially if you are using gpm.
2183 config APM_ALLOW_INTS
2184 bool "Allow interrupts during APM BIOS calls"
2186 Normally we disable external interrupts while we are making calls to
2187 the APM BIOS as a measure to lessen the effects of a badly behaving
2188 BIOS implementation. The BIOS should reenable interrupts if it
2189 needs to. Unfortunately, some BIOSes do not -- especially those in
2190 many of the newer IBM Thinkpads. If you experience hangs when you
2191 suspend, try setting this to Y. Otherwise, say N.
2195 source "drivers/cpufreq/Kconfig"
2197 source "drivers/cpuidle/Kconfig"
2199 source "drivers/idle/Kconfig"
2204 menu "Bus options (PCI etc.)"
2210 Find out whether you have a PCI motherboard. PCI is the name of a
2211 bus system, i.e. the way the CPU talks to the other stuff inside
2212 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2213 VESA. If you have PCI, say Y, otherwise N.
2216 prompt "PCI access mode"
2217 depends on X86_32 && PCI
2220 On PCI systems, the BIOS can be used to detect the PCI devices and
2221 determine their configuration. However, some old PCI motherboards
2222 have BIOS bugs and may crash if this is done. Also, some embedded
2223 PCI-based systems don't have any BIOS at all. Linux can also try to
2224 detect the PCI hardware directly without using the BIOS.
2226 With this option, you can specify how Linux should detect the
2227 PCI devices. If you choose "BIOS", the BIOS will be used,
2228 if you choose "Direct", the BIOS won't be used, and if you
2229 choose "MMConfig", then PCI Express MMCONFIG will be used.
2230 If you choose "Any", the kernel will try MMCONFIG, then the
2231 direct access method and falls back to the BIOS if that doesn't
2232 work. If unsure, go with the default, which is "Any".
2237 config PCI_GOMMCONFIG
2254 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2256 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2259 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2263 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2267 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2271 depends on PCI && XEN
2279 bool "Support mmconfig PCI config space access"
2280 depends on X86_64 && PCI && ACPI
2282 config PCI_CNB20LE_QUIRK
2283 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2286 Read the PCI windows out of the CNB20LE host bridge. This allows
2287 PCI hotplug to work on systems with the CNB20LE chipset which do
2290 There's no public spec for this chipset, and this functionality
2291 is known to be incomplete.
2293 You should say N unless you know you need this.
2295 source "drivers/pci/pcie/Kconfig"
2297 source "drivers/pci/Kconfig"
2299 # x86_64 have no ISA slots, but can have ISA-style DMA.
2301 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2304 Enables ISA-style DMA support for devices requiring such controllers.
2312 Find out whether you have ISA slots on your motherboard. ISA is the
2313 name of a bus system, i.e. the way the CPU talks to the other stuff
2314 inside your box. Other bus systems are PCI, EISA, MicroChannel
2315 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2316 newer boards don't support it. If you have ISA, say Y, otherwise N.
2322 The Extended Industry Standard Architecture (EISA) bus was
2323 developed as an open alternative to the IBM MicroChannel bus.
2325 The EISA bus provided some of the features of the IBM MicroChannel
2326 bus while maintaining backward compatibility with cards made for
2327 the older ISA bus. The EISA bus saw limited use between 1988 and
2328 1995 when it was made obsolete by the PCI bus.
2330 Say Y here if you are building a kernel for an EISA-based machine.
2334 source "drivers/eisa/Kconfig"
2337 tristate "NatSemi SCx200 support"
2339 This provides basic support for National Semiconductor's
2340 (now AMD's) Geode processors. The driver probes for the
2341 PCI-IDs of several on-chip devices, so its a good dependency
2342 for other scx200_* drivers.
2344 If compiled as a module, the driver is named scx200.
2346 config SCx200HR_TIMER
2347 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2351 This driver provides a clocksource built upon the on-chip
2352 27MHz high-resolution timer. Its also a workaround for
2353 NSC Geode SC-1100's buggy TSC, which loses time when the
2354 processor goes idle (as is done by the scheduler). The
2355 other workaround is idle=poll boot option.
2358 bool "One Laptop Per Child support"
2365 Add support for detecting the unique features of the OLPC
2369 bool "OLPC XO-1 Power Management"
2370 depends on OLPC && MFD_CS5535 && PM_SLEEP
2373 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2376 bool "OLPC XO-1 Real Time Clock"
2377 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2379 Add support for the XO-1 real time clock, which can be used as a
2380 programmable wakeup source.
2383 bool "OLPC XO-1 SCI extras"
2384 depends on OLPC && OLPC_XO1_PM
2390 Add support for SCI-based features of the OLPC XO-1 laptop:
2391 - EC-driven system wakeups
2395 - AC adapter status updates
2396 - Battery status updates
2398 config OLPC_XO15_SCI
2399 bool "OLPC XO-1.5 SCI extras"
2400 depends on OLPC && ACPI
2403 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2404 - EC-driven system wakeups
2405 - AC adapter status updates
2406 - Battery status updates
2409 bool "PCEngines ALIX System Support (LED setup)"
2412 This option enables system support for the PCEngines ALIX.
2413 At present this just sets up LEDs for GPIO control on
2414 ALIX2/3/6 boards. However, other system specific setup should
2417 Note: You must still enable the drivers for GPIO and LED support
2418 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2420 Note: You have to set alix.force=1 for boards with Award BIOS.
2423 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2426 This option enables system support for the Soekris Engineering net5501.
2429 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2433 This option enables system support for the Traverse Technologies GEOS.
2436 bool "Technologic Systems TS-5500 platform support"
2438 select CHECK_SIGNATURE
2442 This option enables system support for the Technologic Systems TS-5500.
2448 depends on CPU_SUP_AMD && PCI
2450 source "drivers/pcmcia/Kconfig"
2452 source "drivers/pci/hotplug/Kconfig"
2455 tristate "RapidIO support"
2459 If enabled this option will include drivers and the core
2460 infrastructure code to support RapidIO interconnect devices.
2462 source "drivers/rapidio/Kconfig"
2465 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2467 Firmwares often provide initial graphics framebuffers so the BIOS,
2468 bootloader or kernel can show basic video-output during boot for
2469 user-guidance and debugging. Historically, x86 used the VESA BIOS
2470 Extensions and EFI-framebuffers for this, which are mostly limited
2472 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2473 framebuffers so the new generic system-framebuffer drivers can be
2474 used on x86. If the framebuffer is not compatible with the generic
2475 modes, it is adverticed as fallback platform framebuffer so legacy
2476 drivers like efifb, vesafb and uvesafb can pick it up.
2477 If this option is not selected, all system framebuffers are always
2478 marked as fallback platform framebuffers as usual.
2480 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2481 not be able to pick up generic system framebuffers if this option
2482 is selected. You are highly encouraged to enable simplefb as
2483 replacement if you select this option. simplefb can correctly deal
2484 with generic system framebuffers. But you should still keep vesafb
2485 and others enabled as fallback if a system framebuffer is
2486 incompatible with simplefb.
2493 menu "Executable file formats / Emulations"
2495 source "fs/Kconfig.binfmt"
2497 config IA32_EMULATION
2498 bool "IA32 Emulation"
2501 select COMPAT_BINFMT_ELF
2504 Include code to run legacy 32-bit programs under a
2505 64-bit kernel. You should likely turn this on, unless you're
2506 100% sure that you don't have any 32-bit programs left.
2509 tristate "IA32 a.out support"
2510 depends on IA32_EMULATION
2512 Support old a.out binaries in the 32bit emulation.
2515 bool "x32 ABI for 64-bit mode"
2516 depends on X86_64 && IA32_EMULATION
2518 Include code to run binaries for the x32 native 32-bit ABI
2519 for 64-bit processors. An x32 process gets access to the
2520 full 64-bit register file and wide data path while leaving
2521 pointers at 32 bits for smaller memory footprint.
2523 You will need a recent binutils (2.22 or later) with
2524 elf32_x86_64 support enabled to compile a kernel with this
2529 depends on IA32_EMULATION || X86_X32
2530 select ARCH_WANT_OLD_COMPAT_IPC
2533 config COMPAT_FOR_U64_ALIGNMENT
2536 config SYSVIPC_COMPAT
2548 config HAVE_ATOMIC_IOMAP
2552 config X86_DEV_DMA_OPS
2554 depends on X86_64 || STA2X11
2556 config X86_DMA_REMAP
2564 source "net/Kconfig"
2566 source "drivers/Kconfig"
2568 source "drivers/firmware/Kconfig"
2572 source "arch/x86/Kconfig.debug"
2574 source "security/Kconfig"
2576 source "crypto/Kconfig"
2578 source "arch/x86/kvm/Kconfig"
2580 source "lib/Kconfig"