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
24 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
25 select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
26 select ARCH_HAS_FAST_MULTIPLIER
27 select ARCH_MIGHT_HAVE_PC_PARPORT
28 select ARCH_MIGHT_HAVE_PC_SERIO
29 select HAVE_AOUT if X86_32
30 select HAVE_UNSTABLE_SCHED_CLOCK
31 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
32 select ARCH_SUPPORTS_INT128 if X86_64
35 select HAVE_PCSPKR_PLATFORM
36 select HAVE_PERF_EVENTS
37 select HAVE_IOREMAP_PROT
40 select HAVE_MEMBLOCK_NODE_MAP
41 select ARCH_DISCARD_MEMBLOCK
42 select ARCH_WANT_OPTIONAL_GPIOLIB
43 select ARCH_WANT_FRAME_POINTERS
45 select HAVE_DMA_CONTIGUOUS
46 select HAVE_KRETPROBES
47 select GENERIC_EARLY_IOREMAP
49 select HAVE_KPROBES_ON_FTRACE
50 select HAVE_FTRACE_MCOUNT_RECORD
51 select HAVE_FENTRY if X86_64
52 select HAVE_C_RECORDMCOUNT
53 select HAVE_DYNAMIC_FTRACE
54 select HAVE_DYNAMIC_FTRACE_WITH_REGS
55 select HAVE_FUNCTION_TRACER
56 select HAVE_FUNCTION_GRAPH_TRACER
57 select HAVE_FUNCTION_GRAPH_FP_TEST
58 select HAVE_SYSCALL_TRACEPOINTS
59 select SYSCTL_EXCEPTION_TRACE
62 select HAVE_ARCH_TRACEHOOK
63 select HAVE_GENERIC_DMA_COHERENT if X86_32
64 select HAVE_EFFICIENT_UNALIGNED_ACCESS
65 select USER_STACKTRACE_SUPPORT
66 select HAVE_REGS_AND_STACK_ACCESS_API
67 select HAVE_DMA_API_DEBUG
68 select HAVE_KERNEL_GZIP
69 select HAVE_KERNEL_BZIP2
70 select HAVE_KERNEL_LZMA
72 select HAVE_KERNEL_LZO
73 select HAVE_KERNEL_LZ4
74 select HAVE_HW_BREAKPOINT
75 select HAVE_MIXED_BREAKPOINTS_REGS
77 select HAVE_PERF_EVENTS_NMI
79 select HAVE_PERF_USER_STACK_DUMP
80 select HAVE_DEBUG_KMEMLEAK
82 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
83 select HAVE_CMPXCHG_LOCAL
84 select HAVE_CMPXCHG_DOUBLE
85 select HAVE_ARCH_KMEMCHECK
86 select HAVE_USER_RETURN_NOTIFIER
87 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
88 select HAVE_ARCH_JUMP_LABEL
89 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
91 select GENERIC_FIND_FIRST_BIT
92 select GENERIC_IRQ_PROBE
93 select GENERIC_PENDING_IRQ if SMP
94 select GENERIC_IRQ_SHOW
95 select GENERIC_CLOCKEVENTS_MIN_ADJUST
96 select IRQ_FORCED_THREADING
97 select HAVE_BPF_JIT if X86_64
98 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
99 select ARCH_HAS_SG_CHAIN
101 select ARCH_HAVE_NMI_SAFE_CMPXCHG
103 select DCACHE_WORD_ACCESS
104 select GENERIC_SMP_IDLE_THREAD
105 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
106 select HAVE_ARCH_SECCOMP_FILTER
107 select BUILDTIME_EXTABLE_SORT
108 select GENERIC_CMOS_UPDATE
109 select HAVE_ARCH_SOFT_DIRTY if X86_64
110 select CLOCKSOURCE_WATCHDOG
111 select GENERIC_CLOCKEVENTS
112 select ARCH_CLOCKSOURCE_DATA
113 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
114 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
115 select GENERIC_TIME_VSYSCALL
116 select GENERIC_STRNCPY_FROM_USER
117 select GENERIC_STRNLEN_USER
118 select HAVE_CONTEXT_TRACKING if X86_64
119 select HAVE_IRQ_TIME_ACCOUNTING
121 select MODULES_USE_ELF_REL if X86_32
122 select MODULES_USE_ELF_RELA if X86_64
123 select CLONE_BACKWARDS if X86_32
124 select ARCH_USE_BUILTIN_BSWAP
125 select ARCH_USE_QUEUE_RWLOCK
126 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
127 select OLD_SIGACTION if X86_32
128 select COMPAT_OLD_SIGACTION if IA32_EMULATION
130 select HAVE_DEBUG_STACKOVERFLOW
131 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
132 select HAVE_CC_STACKPROTECTOR
133 select GENERIC_CPU_AUTOPROBE
134 select HAVE_ARCH_AUDITSYSCALL
135 select ARCH_SUPPORTS_ATOMIC_RMW
136 select HAVE_ACPI_APEI if ACPI
137 select HAVE_ACPI_APEI_NMI if ACPI
138 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
139 select X86_FEATURE_NAMES if PROC_FS
141 config INSTRUCTION_DECODER
143 depends on KPROBES || PERF_EVENTS || UPROBES
145 config PERF_EVENTS_INTEL_UNCORE
147 depends on PERF_EVENTS && CPU_SUP_INTEL && PCI
151 default "elf32-i386" if X86_32
152 default "elf64-x86-64" if X86_64
154 config ARCH_DEFCONFIG
156 default "arch/x86/configs/i386_defconfig" if X86_32
157 default "arch/x86/configs/x86_64_defconfig" if X86_64
159 config LOCKDEP_SUPPORT
162 config STACKTRACE_SUPPORT
165 config HAVE_LATENCYTOP_SUPPORT
174 config NEED_DMA_MAP_STATE
176 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
178 config NEED_SG_DMA_LENGTH
181 config GENERIC_ISA_DMA
183 depends on ISA_DMA_API
188 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
190 config GENERIC_BUG_RELATIVE_POINTERS
193 config GENERIC_HWEIGHT
196 config ARCH_MAY_HAVE_PC_FDC
198 depends on ISA_DMA_API
200 config RWSEM_XCHGADD_ALGORITHM
203 config GENERIC_CALIBRATE_DELAY
206 config ARCH_HAS_CPU_RELAX
209 config ARCH_HAS_CACHE_LINE_SIZE
212 config HAVE_SETUP_PER_CPU_AREA
215 config NEED_PER_CPU_EMBED_FIRST_CHUNK
218 config NEED_PER_CPU_PAGE_FIRST_CHUNK
221 config ARCH_HIBERNATION_POSSIBLE
224 config ARCH_SUSPEND_POSSIBLE
227 config ARCH_WANT_HUGE_PMD_SHARE
230 config ARCH_WANT_GENERAL_HUGETLB
241 config ARCH_SUPPORTS_OPTIMIZED_INLINING
244 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
247 config HAVE_INTEL_TXT
249 depends on INTEL_IOMMU && ACPI
253 depends on CPU_SUP_INTEL
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.
503 tristate "Intel SoC IOSF Sideband support for SoC platforms"
506 This option enables sideband register access support for Intel SoC
507 platforms. On these platforms the IOSF sideband is used in lieu of
508 MSR's for some register accesses, mostly but not limited to thermal
509 and power. Drivers may query the availability of this device to
510 determine if they need the sideband in order to work on these
511 platforms. The sideband is available on the following SoC products.
512 This list is not meant to be exclusive.
517 You should say Y if you are running a kernel on one of these SoC's.
519 config IOSF_MBI_DEBUG
520 bool "Enable IOSF sideband access through debugfs"
521 depends on IOSF_MBI && DEBUG_FS
523 Select this option to expose the IOSF sideband access registers (MCR,
524 MDR, MCRX) through debugfs to write and read register information from
525 different units on the SoC. This is most useful for obtaining device
526 state information for debug and analysis. As this is a general access
527 mechanism, users of this option would have specific knowledge of the
528 device they want to access.
530 If you don't require the option or are in doubt, say N.
533 bool "RDC R-321x SoC"
535 depends on X86_EXTENDED_PLATFORM
537 select X86_REBOOTFIXUPS
539 This option is needed for RDC R-321x system-on-chip, also known
541 If you don't have one of these chips, you should say N here.
543 config X86_32_NON_STANDARD
544 bool "Support non-standard 32-bit SMP architectures"
545 depends on X86_32 && SMP
546 depends on X86_EXTENDED_PLATFORM
548 This option compiles in the bigsmp and STA2X11 default
549 subarchitectures. It is intended for a generic binary
550 kernel. If you select them all, kernel will probe it one by
551 one and will fallback to default.
553 # Alphabetically sorted list of Non standard 32 bit platforms
555 config X86_SUPPORTS_MEMORY_FAILURE
557 # MCE code calls memory_failure():
559 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
560 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
561 depends on X86_64 || !SPARSEMEM
562 select ARCH_SUPPORTS_MEMORY_FAILURE
565 bool "STA2X11 Companion Chip Support"
566 depends on X86_32_NON_STANDARD && PCI
567 select X86_DEV_DMA_OPS
571 select ARCH_REQUIRE_GPIOLIB
574 This adds support for boards based on the STA2X11 IO-Hub,
575 a.k.a. "ConneXt". The chip is used in place of the standard
576 PC chipset, so all "standard" peripherals are missing. If this
577 option is selected the kernel will still be able to boot on
578 standard PC machines.
581 tristate "Eurobraille/Iris poweroff module"
584 The Iris machines from EuroBraille do not have APM or ACPI support
585 to shut themselves down properly. A special I/O sequence is
586 needed to do so, which is what this module does at
589 This is only for Iris machines from EuroBraille.
593 config SCHED_OMIT_FRAME_POINTER
595 prompt "Single-depth WCHAN output"
598 Calculate simpler /proc/<PID>/wchan values. If this option
599 is disabled then wchan values will recurse back to the
600 caller function. This provides more accurate wchan values,
601 at the expense of slightly more scheduling overhead.
603 If in doubt, say "Y".
605 menuconfig HYPERVISOR_GUEST
606 bool "Linux guest support"
608 Say Y here to enable options for running Linux under various hyper-
609 visors. This option enables basic hypervisor detection and platform
612 If you say N, all options in this submenu will be skipped and
613 disabled, and Linux guest support won't be built in.
618 bool "Enable paravirtualization code"
620 This changes the kernel so it can modify itself when it is run
621 under a hypervisor, potentially improving performance significantly
622 over full virtualization. However, when run without a hypervisor
623 the kernel is theoretically slower and slightly larger.
625 config PARAVIRT_DEBUG
626 bool "paravirt-ops debugging"
627 depends on PARAVIRT && DEBUG_KERNEL
629 Enable to debug paravirt_ops internals. Specifically, BUG if
630 a paravirt_op is missing when it is called.
632 config PARAVIRT_SPINLOCKS
633 bool "Paravirtualization layer for spinlocks"
634 depends on PARAVIRT && SMP
635 select UNINLINE_SPIN_UNLOCK
637 Paravirtualized spinlocks allow a pvops backend to replace the
638 spinlock implementation with something virtualization-friendly
639 (for example, block the virtual CPU rather than spinning).
641 It has a minimal impact on native kernels and gives a nice performance
642 benefit on paravirtualized KVM / Xen kernels.
644 If you are unsure how to answer this question, answer Y.
646 source "arch/x86/xen/Kconfig"
649 bool "KVM Guest support (including kvmclock)"
651 select PARAVIRT_CLOCK
654 This option enables various optimizations for running under the KVM
655 hypervisor. It includes a paravirtualized clock, so that instead
656 of relying on a PIT (or probably other) emulation by the
657 underlying device model, the host provides the guest with
658 timing infrastructure such as time of day, and system time
661 bool "Enable debug information for KVM Guests in debugfs"
662 depends on KVM_GUEST && DEBUG_FS
665 This option enables collection of various statistics for KVM guest.
666 Statistics are displayed in debugfs filesystem. Enabling this option
667 may incur significant overhead.
669 source "arch/x86/lguest/Kconfig"
671 config PARAVIRT_TIME_ACCOUNTING
672 bool "Paravirtual steal time accounting"
676 Select this option to enable fine granularity task steal time
677 accounting. Time spent executing other tasks in parallel with
678 the current vCPU is discounted from the vCPU power. To account for
679 that, there can be a small performance impact.
681 If in doubt, say N here.
683 config PARAVIRT_CLOCK
686 endif #HYPERVISOR_GUEST
694 This option adds a kernel parameter 'memtest', which allows memtest
696 memtest=0, mean disabled; -- default
697 memtest=1, mean do 1 test pattern;
699 memtest=4, mean do 4 test patterns.
700 If you are unsure how to answer this question, answer N.
702 source "arch/x86/Kconfig.cpu"
706 prompt "HPET Timer Support" if X86_32
708 Use the IA-PC HPET (High Precision Event Timer) to manage
709 time in preference to the PIT and RTC, if a HPET is
711 HPET is the next generation timer replacing legacy 8254s.
712 The HPET provides a stable time base on SMP
713 systems, unlike the TSC, but it is more expensive to access,
714 as it is off-chip. You can find the HPET spec at
715 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
717 You can safely choose Y here. However, HPET will only be
718 activated if the platform and the BIOS support this feature.
719 Otherwise the 8254 will be used for timing services.
721 Choose N to continue using the legacy 8254 timer.
723 config HPET_EMULATE_RTC
725 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
728 def_bool y if X86_INTEL_MID
729 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
731 depends on X86_INTEL_MID && SFI
733 APB timer is the replacement for 8254, HPET on X86 MID platforms.
734 The APBT provides a stable time base on SMP
735 systems, unlike the TSC, but it is more expensive to access,
736 as it is off-chip. APB timers are always running regardless of CPU
737 C states, they are used as per CPU clockevent device when possible.
739 # Mark as expert because too many people got it wrong.
740 # The code disables itself when not needed.
743 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
744 bool "Enable DMI scanning" if EXPERT
746 Enabled scanning of DMI to identify machine quirks. Say Y
747 here unless you have verified that your setup is not
748 affected by entries in the DMI blacklist. Required by PNP
752 bool "Old AMD GART IOMMU support"
754 depends on X86_64 && PCI && AMD_NB
756 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
757 GART based hardware IOMMUs.
759 The GART supports full DMA access for devices with 32-bit access
760 limitations, on systems with more than 3 GB. This is usually needed
761 for USB, sound, many IDE/SATA chipsets and some other devices.
763 Newer systems typically have a modern AMD IOMMU, supported via
764 the CONFIG_AMD_IOMMU=y config option.
766 In normal configurations this driver is only active when needed:
767 there's more than 3 GB of memory and the system contains a
768 32-bit limited device.
773 bool "IBM Calgary IOMMU support"
775 depends on X86_64 && PCI
777 Support for hardware IOMMUs in IBM's xSeries x366 and x460
778 systems. Needed to run systems with more than 3GB of memory
779 properly with 32-bit PCI devices that do not support DAC
780 (Double Address Cycle). Calgary also supports bus level
781 isolation, where all DMAs pass through the IOMMU. This
782 prevents them from going anywhere except their intended
783 destination. This catches hard-to-find kernel bugs and
784 mis-behaving drivers and devices that do not use the DMA-API
785 properly to set up their DMA buffers. The IOMMU can be
786 turned off at boot time with the iommu=off parameter.
787 Normally the kernel will make the right choice by itself.
790 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
792 prompt "Should Calgary be enabled by default?"
793 depends on CALGARY_IOMMU
795 Should Calgary be enabled by default? if you choose 'y', Calgary
796 will be used (if it exists). If you choose 'n', Calgary will not be
797 used even if it exists. If you choose 'n' and would like to use
798 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
801 # need this always selected by IOMMU for the VIA workaround
805 Support for software bounce buffers used on x86-64 systems
806 which don't have a hardware IOMMU. Using this PCI devices
807 which can only access 32-bits of memory can be used on systems
808 with more than 3 GB of memory.
813 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
816 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
817 depends on X86_64 && SMP && DEBUG_KERNEL
818 select CPUMASK_OFFSTACK
820 Enable maximum number of CPUS and NUMA Nodes for this architecture.
824 int "Maximum number of CPUs" if SMP && !MAXSMP
825 range 2 8 if SMP && X86_32 && !X86_BIGSMP
826 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
827 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
829 default "8192" if MAXSMP
830 default "32" if SMP && X86_BIGSMP
833 This allows you to specify the maximum number of CPUs which this
834 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
835 supported value is 4096, otherwise the maximum value is 512. The
836 minimum value which makes sense is 2.
838 This is purely to save memory - each supported CPU adds
839 approximately eight kilobytes to the kernel image.
842 bool "SMT (Hyperthreading) scheduler support"
845 SMT scheduler support improves the CPU scheduler's decision making
846 when dealing with Intel Pentium 4 chips with HyperThreading at a
847 cost of slightly increased overhead in some places. If unsure say
852 prompt "Multi-core scheduler support"
855 Multi-core scheduler support improves the CPU scheduler's decision
856 making when dealing with multi-core CPU chips at a cost of slightly
857 increased overhead in some places. If unsure say N here.
859 source "kernel/Kconfig.preempt"
862 bool "Local APIC support on uniprocessors"
863 depends on X86_32 && !SMP && !X86_32_NON_STANDARD && !PCI_MSI
865 A local APIC (Advanced Programmable Interrupt Controller) is an
866 integrated interrupt controller in the CPU. If you have a single-CPU
867 system which has a processor with a local APIC, you can say Y here to
868 enable and use it. If you say Y here even though your machine doesn't
869 have a local APIC, then the kernel will still run with no slowdown at
870 all. The local APIC supports CPU-generated self-interrupts (timer,
871 performance counters), and the NMI watchdog which detects hard
875 bool "IO-APIC support on uniprocessors"
876 depends on X86_UP_APIC
878 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
879 SMP-capable replacement for PC-style interrupt controllers. Most
880 SMP systems and many recent uniprocessor systems have one.
882 If you have a single-CPU system with an IO-APIC, you can say Y here
883 to use it. If you say Y here even though your machine doesn't have
884 an IO-APIC, then the kernel will still run with no slowdown at all.
886 config X86_LOCAL_APIC
888 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
892 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC || PCI_MSI
893 select GENERIC_IRQ_LEGACY_ALLOC_HWIRQ
896 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
897 bool "Reroute for broken boot IRQs"
898 depends on X86_IO_APIC
900 This option enables a workaround that fixes a source of
901 spurious interrupts. This is recommended when threaded
902 interrupt handling is used on systems where the generation of
903 superfluous "boot interrupts" cannot be disabled.
905 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
906 entry in the chipset's IO-APIC is masked (as, e.g. the RT
907 kernel does during interrupt handling). On chipsets where this
908 boot IRQ generation cannot be disabled, this workaround keeps
909 the original IRQ line masked so that only the equivalent "boot
910 IRQ" is delivered to the CPUs. The workaround also tells the
911 kernel to set up the IRQ handler on the boot IRQ line. In this
912 way only one interrupt is delivered to the kernel. Otherwise
913 the spurious second interrupt may cause the kernel to bring
914 down (vital) interrupt lines.
916 Only affects "broken" chipsets. Interrupt sharing may be
917 increased on these systems.
920 bool "Machine Check / overheating reporting"
923 Machine Check support allows the processor to notify the
924 kernel if it detects a problem (e.g. overheating, data corruption).
925 The action the kernel takes depends on the severity of the problem,
926 ranging from warning messages to halting the machine.
930 prompt "Intel MCE features"
931 depends on X86_MCE && X86_LOCAL_APIC
933 Additional support for intel specific MCE features such as
938 prompt "AMD MCE features"
939 depends on X86_MCE && X86_LOCAL_APIC
941 Additional support for AMD specific MCE features such as
942 the DRAM Error Threshold.
944 config X86_ANCIENT_MCE
945 bool "Support for old Pentium 5 / WinChip machine checks"
946 depends on X86_32 && X86_MCE
948 Include support for machine check handling on old Pentium 5 or WinChip
949 systems. These typically need to be enabled explicitly on the command
952 config X86_MCE_THRESHOLD
953 depends on X86_MCE_AMD || X86_MCE_INTEL
956 config X86_MCE_INJECT
958 tristate "Machine check injector support"
960 Provide support for injecting machine checks for testing purposes.
961 If you don't know what a machine check is and you don't do kernel
962 QA it is safe to say n.
964 config X86_THERMAL_VECTOR
966 depends on X86_MCE_INTEL
969 bool "Enable VM86 support" if EXPERT
973 This option is required by programs like DOSEMU to run
974 16-bit real mode legacy code on x86 processors. It also may
975 be needed by software like XFree86 to initialize some video
976 cards via BIOS. Disabling this option saves about 6K.
979 bool "Enable support for 16-bit segments" if EXPERT
982 This option is required by programs like Wine to run 16-bit
983 protected mode legacy code on x86 processors. Disabling
984 this option saves about 300 bytes on i386, or around 6K text
985 plus 16K runtime memory on x86-64,
989 depends on X86_16BIT && X86_32
993 depends on X86_16BIT && X86_64
995 config X86_VSYSCALL_EMULATION
996 bool "Enable vsyscall emulation" if EXPERT
1000 This enables emulation of the legacy vsyscall page. Disabling
1001 it is roughly equivalent to booting with vsyscall=none, except
1002 that it will also disable the helpful warning if a program
1003 tries to use a vsyscall. With this option set to N, offending
1004 programs will just segfault, citing addresses of the form
1007 This option is required by many programs built before 2013, and
1008 care should be used even with newer programs if set to N.
1010 Disabling this option saves about 7K of kernel size and
1011 possibly 4K of additional runtime pagetable memory.
1014 tristate "Toshiba Laptop support"
1017 This adds a driver to safely access the System Management Mode of
1018 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1019 not work on models with a Phoenix BIOS. The System Management Mode
1020 is used to set the BIOS and power saving options on Toshiba portables.
1022 For information on utilities to make use of this driver see the
1023 Toshiba Linux utilities web site at:
1024 <http://www.buzzard.org.uk/toshiba/>.
1026 Say Y if you intend to run this kernel on a Toshiba portable.
1030 tristate "Dell laptop support"
1033 This adds a driver to safely access the System Management Mode
1034 of the CPU on the Dell Inspiron 8000. The System Management Mode
1035 is used to read cpu temperature and cooling fan status and to
1036 control the fans on the I8K portables.
1038 This driver has been tested only on the Inspiron 8000 but it may
1039 also work with other Dell laptops. You can force loading on other
1040 models by passing the parameter `force=1' to the module. Use at
1043 For information on utilities to make use of this driver see the
1044 I8K Linux utilities web site at:
1045 <http://people.debian.org/~dz/i8k/>
1047 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
1050 config X86_REBOOTFIXUPS
1051 bool "Enable X86 board specific fixups for reboot"
1054 This enables chipset and/or board specific fixups to be done
1055 in order to get reboot to work correctly. This is only needed on
1056 some combinations of hardware and BIOS. The symptom, for which
1057 this config is intended, is when reboot ends with a stalled/hung
1060 Currently, the only fixup is for the Geode machines using
1061 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1063 Say Y if you want to enable the fixup. Currently, it's safe to
1064 enable this option even if you don't need it.
1068 tristate "CPU microcode loading support"
1069 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1073 If you say Y here, you will be able to update the microcode on
1074 certain Intel and AMD processors. The Intel support is for the
1075 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1076 Xeon etc. The AMD support is for families 0x10 and later. You will
1077 obviously need the actual microcode binary data itself which is not
1078 shipped with the Linux kernel.
1080 This option selects the general module only, you need to select
1081 at least one vendor specific module as well.
1083 To compile this driver as a module, choose M here: the module
1084 will be called microcode.
1086 config MICROCODE_INTEL
1087 bool "Intel microcode loading support"
1088 depends on MICROCODE
1092 This options enables microcode patch loading support for Intel
1095 For the current Intel microcode data package go to
1096 <https://downloadcenter.intel.com> and search for
1097 'Linux Processor Microcode Data File'.
1099 config MICROCODE_AMD
1100 bool "AMD microcode loading support"
1101 depends on MICROCODE
1104 If you select this option, microcode patch loading support for AMD
1105 processors will be enabled.
1107 config MICROCODE_OLD_INTERFACE
1109 depends on MICROCODE
1111 config MICROCODE_INTEL_EARLY
1114 config MICROCODE_AMD_EARLY
1117 config MICROCODE_EARLY
1118 bool "Early load microcode"
1119 depends on MICROCODE=y && BLK_DEV_INITRD
1120 select MICROCODE_INTEL_EARLY if MICROCODE_INTEL
1121 select MICROCODE_AMD_EARLY if MICROCODE_AMD
1124 This option provides functionality to read additional microcode data
1125 at the beginning of initrd image. The data tells kernel to load
1126 microcode to CPU's as early as possible. No functional change if no
1127 microcode data is glued to the initrd, therefore it's safe to say Y.
1130 tristate "/dev/cpu/*/msr - Model-specific register support"
1132 This device gives privileged processes access to the x86
1133 Model-Specific Registers (MSRs). It is a character device with
1134 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1135 MSR accesses are directed to a specific CPU on multi-processor
1139 tristate "/dev/cpu/*/cpuid - CPU information support"
1141 This device gives processes access to the x86 CPUID instruction to
1142 be executed on a specific processor. It is a character device
1143 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1147 prompt "High Memory Support"
1154 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1155 However, the address space of 32-bit x86 processors is only 4
1156 Gigabytes large. That means that, if you have a large amount of
1157 physical memory, not all of it can be "permanently mapped" by the
1158 kernel. The physical memory that's not permanently mapped is called
1161 If you are compiling a kernel which will never run on a machine with
1162 more than 1 Gigabyte total physical RAM, answer "off" here (default
1163 choice and suitable for most users). This will result in a "3GB/1GB"
1164 split: 3GB are mapped so that each process sees a 3GB virtual memory
1165 space and the remaining part of the 4GB virtual memory space is used
1166 by the kernel to permanently map as much physical memory as
1169 If the machine has between 1 and 4 Gigabytes physical RAM, then
1172 If more than 4 Gigabytes is used then answer "64GB" here. This
1173 selection turns Intel PAE (Physical Address Extension) mode on.
1174 PAE implements 3-level paging on IA32 processors. PAE is fully
1175 supported by Linux, PAE mode is implemented on all recent Intel
1176 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1177 then the kernel will not boot on CPUs that don't support PAE!
1179 The actual amount of total physical memory will either be
1180 auto detected or can be forced by using a kernel command line option
1181 such as "mem=256M". (Try "man bootparam" or see the documentation of
1182 your boot loader (lilo or loadlin) about how to pass options to the
1183 kernel at boot time.)
1185 If unsure, say "off".
1190 Select this if you have a 32-bit processor and between 1 and 4
1191 gigabytes of physical RAM.
1198 Select this if you have a 32-bit processor and more than 4
1199 gigabytes of physical RAM.
1204 prompt "Memory split" if EXPERT
1208 Select the desired split between kernel and user memory.
1210 If the address range available to the kernel is less than the
1211 physical memory installed, the remaining memory will be available
1212 as "high memory". Accessing high memory is a little more costly
1213 than low memory, as it needs to be mapped into the kernel first.
1214 Note that increasing the kernel address space limits the range
1215 available to user programs, making the address space there
1216 tighter. Selecting anything other than the default 3G/1G split
1217 will also likely make your kernel incompatible with binary-only
1220 If you are not absolutely sure what you are doing, leave this
1224 bool "3G/1G user/kernel split"
1225 config VMSPLIT_3G_OPT
1227 bool "3G/1G user/kernel split (for full 1G low memory)"
1229 bool "2G/2G user/kernel split"
1230 config VMSPLIT_2G_OPT
1232 bool "2G/2G user/kernel split (for full 2G low memory)"
1234 bool "1G/3G user/kernel split"
1239 default 0xB0000000 if VMSPLIT_3G_OPT
1240 default 0x80000000 if VMSPLIT_2G
1241 default 0x78000000 if VMSPLIT_2G_OPT
1242 default 0x40000000 if VMSPLIT_1G
1248 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1251 bool "PAE (Physical Address Extension) Support"
1252 depends on X86_32 && !HIGHMEM4G
1254 PAE is required for NX support, and furthermore enables
1255 larger swapspace support for non-overcommit purposes. It
1256 has the cost of more pagetable lookup overhead, and also
1257 consumes more pagetable space per process.
1259 config ARCH_PHYS_ADDR_T_64BIT
1261 depends on X86_64 || X86_PAE
1263 config ARCH_DMA_ADDR_T_64BIT
1265 depends on X86_64 || HIGHMEM64G
1267 config DIRECT_GBPAGES
1268 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1272 Allow the kernel linear mapping to use 1GB pages on CPUs that
1273 support it. This can improve the kernel's performance a tiny bit by
1274 reducing TLB pressure. If in doubt, say "Y".
1276 # Common NUMA Features
1278 bool "Numa Memory Allocation and Scheduler Support"
1280 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1281 default y if X86_BIGSMP
1283 Enable NUMA (Non Uniform Memory Access) support.
1285 The kernel will try to allocate memory used by a CPU on the
1286 local memory controller of the CPU and add some more
1287 NUMA awareness to the kernel.
1289 For 64-bit this is recommended if the system is Intel Core i7
1290 (or later), AMD Opteron, or EM64T NUMA.
1292 For 32-bit this is only needed if you boot a 32-bit
1293 kernel on a 64-bit NUMA platform.
1295 Otherwise, you should say N.
1299 prompt "Old style AMD Opteron NUMA detection"
1300 depends on X86_64 && NUMA && PCI
1302 Enable AMD NUMA node topology detection. You should say Y here if
1303 you have a multi processor AMD system. This uses an old method to
1304 read the NUMA configuration directly from the builtin Northbridge
1305 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1306 which also takes priority if both are compiled in.
1308 config X86_64_ACPI_NUMA
1310 prompt "ACPI NUMA detection"
1311 depends on X86_64 && NUMA && ACPI && PCI
1314 Enable ACPI SRAT based node topology detection.
1316 # Some NUMA nodes have memory ranges that span
1317 # other nodes. Even though a pfn is valid and
1318 # between a node's start and end pfns, it may not
1319 # reside on that node. See memmap_init_zone()
1321 config NODES_SPAN_OTHER_NODES
1323 depends on X86_64_ACPI_NUMA
1326 bool "NUMA emulation"
1329 Enable NUMA emulation. A flat machine will be split
1330 into virtual nodes when booted with "numa=fake=N", where N is the
1331 number of nodes. This is only useful for debugging.
1334 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1336 default "10" if MAXSMP
1337 default "6" if X86_64
1339 depends on NEED_MULTIPLE_NODES
1341 Specify the maximum number of NUMA Nodes available on the target
1342 system. Increases memory reserved to accommodate various tables.
1344 config ARCH_HAVE_MEMORY_PRESENT
1346 depends on X86_32 && DISCONTIGMEM
1348 config NEED_NODE_MEMMAP_SIZE
1350 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1352 config ARCH_FLATMEM_ENABLE
1354 depends on X86_32 && !NUMA
1356 config ARCH_DISCONTIGMEM_ENABLE
1358 depends on NUMA && X86_32
1360 config ARCH_DISCONTIGMEM_DEFAULT
1362 depends on NUMA && X86_32
1364 config ARCH_SPARSEMEM_ENABLE
1366 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1367 select SPARSEMEM_STATIC if X86_32
1368 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1370 config ARCH_SPARSEMEM_DEFAULT
1374 config ARCH_SELECT_MEMORY_MODEL
1376 depends on ARCH_SPARSEMEM_ENABLE
1378 config ARCH_MEMORY_PROBE
1379 bool "Enable sysfs memory/probe interface"
1380 depends on X86_64 && MEMORY_HOTPLUG
1382 This option enables a sysfs memory/probe interface for testing.
1383 See Documentation/memory-hotplug.txt for more information.
1384 If you are unsure how to answer this question, answer N.
1386 config ARCH_PROC_KCORE_TEXT
1388 depends on X86_64 && PROC_KCORE
1390 config ILLEGAL_POINTER_VALUE
1393 default 0xdead000000000000 if X86_64
1398 bool "Allocate 3rd-level pagetables from highmem"
1401 The VM uses one page table entry for each page of physical memory.
1402 For systems with a lot of RAM, this can be wasteful of precious
1403 low memory. Setting this option will put user-space page table
1404 entries in high memory.
1406 config X86_CHECK_BIOS_CORRUPTION
1407 bool "Check for low memory corruption"
1409 Periodically check for memory corruption in low memory, which
1410 is suspected to be caused by BIOS. Even when enabled in the
1411 configuration, it is disabled at runtime. Enable it by
1412 setting "memory_corruption_check=1" on the kernel command
1413 line. By default it scans the low 64k of memory every 60
1414 seconds; see the memory_corruption_check_size and
1415 memory_corruption_check_period parameters in
1416 Documentation/kernel-parameters.txt to adjust this.
1418 When enabled with the default parameters, this option has
1419 almost no overhead, as it reserves a relatively small amount
1420 of memory and scans it infrequently. It both detects corruption
1421 and prevents it from affecting the running system.
1423 It is, however, intended as a diagnostic tool; if repeatable
1424 BIOS-originated corruption always affects the same memory,
1425 you can use memmap= to prevent the kernel from using that
1428 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1429 bool "Set the default setting of memory_corruption_check"
1430 depends on X86_CHECK_BIOS_CORRUPTION
1433 Set whether the default state of memory_corruption_check is
1436 config X86_RESERVE_LOW
1437 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1441 Specify the amount of low memory to reserve for the BIOS.
1443 The first page contains BIOS data structures that the kernel
1444 must not use, so that page must always be reserved.
1446 By default we reserve the first 64K of physical RAM, as a
1447 number of BIOSes are known to corrupt that memory range
1448 during events such as suspend/resume or monitor cable
1449 insertion, so it must not be used by the kernel.
1451 You can set this to 4 if you are absolutely sure that you
1452 trust the BIOS to get all its memory reservations and usages
1453 right. If you know your BIOS have problems beyond the
1454 default 64K area, you can set this to 640 to avoid using the
1455 entire low memory range.
1457 If you have doubts about the BIOS (e.g. suspend/resume does
1458 not work or there's kernel crashes after certain hardware
1459 hotplug events) then you might want to enable
1460 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1461 typical corruption patterns.
1463 Leave this to the default value of 64 if you are unsure.
1465 config MATH_EMULATION
1467 prompt "Math emulation" if X86_32
1469 Linux can emulate a math coprocessor (used for floating point
1470 operations) if you don't have one. 486DX and Pentium processors have
1471 a math coprocessor built in, 486SX and 386 do not, unless you added
1472 a 487DX or 387, respectively. (The messages during boot time can
1473 give you some hints here ["man dmesg"].) Everyone needs either a
1474 coprocessor or this emulation.
1476 If you don't have a math coprocessor, you need to say Y here; if you
1477 say Y here even though you have a coprocessor, the coprocessor will
1478 be used nevertheless. (This behavior can be changed with the kernel
1479 command line option "no387", which comes handy if your coprocessor
1480 is broken. Try "man bootparam" or see the documentation of your boot
1481 loader (lilo or loadlin) about how to pass options to the kernel at
1482 boot time.) This means that it is a good idea to say Y here if you
1483 intend to use this kernel on different machines.
1485 More information about the internals of the Linux math coprocessor
1486 emulation can be found in <file:arch/x86/math-emu/README>.
1488 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1489 kernel, it won't hurt.
1493 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1495 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1496 the Memory Type Range Registers (MTRRs) may be used to control
1497 processor access to memory ranges. This is most useful if you have
1498 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1499 allows bus write transfers to be combined into a larger transfer
1500 before bursting over the PCI/AGP bus. This can increase performance
1501 of image write operations 2.5 times or more. Saying Y here creates a
1502 /proc/mtrr file which may be used to manipulate your processor's
1503 MTRRs. Typically the X server should use this.
1505 This code has a reasonably generic interface so that similar
1506 control registers on other processors can be easily supported
1509 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1510 Registers (ARRs) which provide a similar functionality to MTRRs. For
1511 these, the ARRs are used to emulate the MTRRs.
1512 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1513 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1514 write-combining. All of these processors are supported by this code
1515 and it makes sense to say Y here if you have one of them.
1517 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1518 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1519 can lead to all sorts of problems, so it's good to say Y here.
1521 You can safely say Y even if your machine doesn't have MTRRs, you'll
1522 just add about 9 KB to your kernel.
1524 See <file:Documentation/x86/mtrr.txt> for more information.
1526 config MTRR_SANITIZER
1528 prompt "MTRR cleanup support"
1531 Convert MTRR layout from continuous to discrete, so X drivers can
1532 add writeback entries.
1534 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1535 The largest mtrr entry size for a continuous block can be set with
1540 config MTRR_SANITIZER_ENABLE_DEFAULT
1541 int "MTRR cleanup enable value (0-1)"
1544 depends on MTRR_SANITIZER
1546 Enable mtrr cleanup default value
1548 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1549 int "MTRR cleanup spare reg num (0-7)"
1552 depends on MTRR_SANITIZER
1554 mtrr cleanup spare entries default, it can be changed via
1555 mtrr_spare_reg_nr=N on the kernel command line.
1559 prompt "x86 PAT support" if EXPERT
1562 Use PAT attributes to setup page level cache control.
1564 PATs are the modern equivalents of MTRRs and are much more
1565 flexible than MTRRs.
1567 Say N here if you see bootup problems (boot crash, boot hang,
1568 spontaneous reboots) or a non-working video driver.
1572 config ARCH_USES_PG_UNCACHED
1578 prompt "x86 architectural random number generator" if EXPERT
1580 Enable the x86 architectural RDRAND instruction
1581 (Intel Bull Mountain technology) to generate random numbers.
1582 If supported, this is a high bandwidth, cryptographically
1583 secure hardware random number generator.
1587 prompt "Supervisor Mode Access Prevention" if EXPERT
1589 Supervisor Mode Access Prevention (SMAP) is a security
1590 feature in newer Intel processors. There is a small
1591 performance cost if this enabled and turned on; there is
1592 also a small increase in the kernel size if this is enabled.
1597 bool "EFI runtime service support"
1600 select EFI_RUNTIME_WRAPPERS
1602 This enables the kernel to use EFI runtime services that are
1603 available (such as the EFI variable services).
1605 This option is only useful on systems that have EFI firmware.
1606 In addition, you should use the latest ELILO loader available
1607 at <http://elilo.sourceforge.net> in order to take advantage
1608 of EFI runtime services. However, even with this option, the
1609 resultant kernel should continue to boot on existing non-EFI
1613 bool "EFI stub support"
1614 depends on EFI && !X86_USE_3DNOW
1617 This kernel feature allows a bzImage to be loaded directly
1618 by EFI firmware without the use of a bootloader.
1620 See Documentation/efi-stub.txt for more information.
1623 bool "EFI mixed-mode support"
1624 depends on EFI_STUB && X86_64
1626 Enabling this feature allows a 64-bit kernel to be booted
1627 on a 32-bit firmware, provided that your CPU supports 64-bit
1630 Note that it is not possible to boot a mixed-mode enabled
1631 kernel via the EFI boot stub - a bootloader that supports
1632 the EFI handover protocol must be used.
1638 prompt "Enable seccomp to safely compute untrusted bytecode"
1640 This kernel feature is useful for number crunching applications
1641 that may need to compute untrusted bytecode during their
1642 execution. By using pipes or other transports made available to
1643 the process as file descriptors supporting the read/write
1644 syscalls, it's possible to isolate those applications in
1645 their own address space using seccomp. Once seccomp is
1646 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1647 and the task is only allowed to execute a few safe syscalls
1648 defined by each seccomp mode.
1650 If unsure, say Y. Only embedded should say N here.
1652 source kernel/Kconfig.hz
1655 bool "kexec system call"
1657 kexec is a system call that implements the ability to shutdown your
1658 current kernel, and to start another kernel. It is like a reboot
1659 but it is independent of the system firmware. And like a reboot
1660 you can start any kernel with it, not just Linux.
1662 The name comes from the similarity to the exec system call.
1664 It is an ongoing process to be certain the hardware in a machine
1665 is properly shutdown, so do not be surprised if this code does not
1666 initially work for you. As of this writing the exact hardware
1667 interface is strongly in flux, so no good recommendation can be
1671 bool "kexec file based system call"
1676 depends on CRYPTO_SHA256=y
1678 This is new version of kexec system call. This system call is
1679 file based and takes file descriptors as system call argument
1680 for kernel and initramfs as opposed to list of segments as
1681 accepted by previous system call.
1683 config KEXEC_VERIFY_SIG
1684 bool "Verify kernel signature during kexec_file_load() syscall"
1685 depends on KEXEC_FILE
1687 This option makes kernel signature verification mandatory for
1688 kexec_file_load() syscall. If kernel is signature can not be
1689 verified, kexec_file_load() will fail.
1691 This option enforces signature verification at generic level.
1692 One needs to enable signature verification for type of kernel
1693 image being loaded to make sure it works. For example, enable
1694 bzImage signature verification option to be able to load and
1695 verify signatures of bzImage. Otherwise kernel loading will fail.
1697 config KEXEC_BZIMAGE_VERIFY_SIG
1698 bool "Enable bzImage signature verification support"
1699 depends on KEXEC_VERIFY_SIG
1700 depends on SIGNED_PE_FILE_VERIFICATION
1701 select SYSTEM_TRUSTED_KEYRING
1703 Enable bzImage signature verification support.
1706 bool "kernel crash dumps"
1707 depends on X86_64 || (X86_32 && HIGHMEM)
1709 Generate crash dump after being started by kexec.
1710 This should be normally only set in special crash dump kernels
1711 which are loaded in the main kernel with kexec-tools into
1712 a specially reserved region and then later executed after
1713 a crash by kdump/kexec. The crash dump kernel must be compiled
1714 to a memory address not used by the main kernel or BIOS using
1715 PHYSICAL_START, or it must be built as a relocatable image
1716 (CONFIG_RELOCATABLE=y).
1717 For more details see Documentation/kdump/kdump.txt
1721 depends on KEXEC && HIBERNATION
1723 Jump between original kernel and kexeced kernel and invoke
1724 code in physical address mode via KEXEC
1726 config PHYSICAL_START
1727 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1730 This gives the physical address where the kernel is loaded.
1732 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1733 bzImage will decompress itself to above physical address and
1734 run from there. Otherwise, bzImage will run from the address where
1735 it has been loaded by the boot loader and will ignore above physical
1738 In normal kdump cases one does not have to set/change this option
1739 as now bzImage can be compiled as a completely relocatable image
1740 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1741 address. This option is mainly useful for the folks who don't want
1742 to use a bzImage for capturing the crash dump and want to use a
1743 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1744 to be specifically compiled to run from a specific memory area
1745 (normally a reserved region) and this option comes handy.
1747 So if you are using bzImage for capturing the crash dump,
1748 leave the value here unchanged to 0x1000000 and set
1749 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1750 for capturing the crash dump change this value to start of
1751 the reserved region. In other words, it can be set based on
1752 the "X" value as specified in the "crashkernel=YM@XM"
1753 command line boot parameter passed to the panic-ed
1754 kernel. Please take a look at Documentation/kdump/kdump.txt
1755 for more details about crash dumps.
1757 Usage of bzImage for capturing the crash dump is recommended as
1758 one does not have to build two kernels. Same kernel can be used
1759 as production kernel and capture kernel. Above option should have
1760 gone away after relocatable bzImage support is introduced. But it
1761 is present because there are users out there who continue to use
1762 vmlinux for dump capture. This option should go away down the
1765 Don't change this unless you know what you are doing.
1768 bool "Build a relocatable kernel"
1771 This builds a kernel image that retains relocation information
1772 so it can be loaded someplace besides the default 1MB.
1773 The relocations tend to make the kernel binary about 10% larger,
1774 but are discarded at runtime.
1776 One use is for the kexec on panic case where the recovery kernel
1777 must live at a different physical address than the primary
1780 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1781 it has been loaded at and the compile time physical address
1782 (CONFIG_PHYSICAL_START) is used as the minimum location.
1784 config RANDOMIZE_BASE
1785 bool "Randomize the address of the kernel image"
1786 depends on RELOCATABLE
1789 Randomizes the physical and virtual address at which the
1790 kernel image is decompressed, as a security feature that
1791 deters exploit attempts relying on knowledge of the location
1792 of kernel internals.
1794 Entropy is generated using the RDRAND instruction if it is
1795 supported. If RDTSC is supported, it is used as well. If
1796 neither RDRAND nor RDTSC are supported, then randomness is
1797 read from the i8254 timer.
1799 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1800 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1801 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1802 minimum of 2MiB, only 10 bits of entropy is theoretically
1803 possible. At best, due to page table layouts, 64-bit can use
1804 9 bits of entropy and 32-bit uses 8 bits.
1808 config RANDOMIZE_BASE_MAX_OFFSET
1809 hex "Maximum kASLR offset allowed" if EXPERT
1810 depends on RANDOMIZE_BASE
1811 range 0x0 0x20000000 if X86_32
1812 default "0x20000000" if X86_32
1813 range 0x0 0x40000000 if X86_64
1814 default "0x40000000" if X86_64
1816 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1817 memory is used to determine the maximal offset in bytes that will
1818 be applied to the kernel when kernel Address Space Layout
1819 Randomization (kASLR) is active. This must be a multiple of
1822 On 32-bit this is limited to 512MiB by page table layouts. The
1825 On 64-bit this is limited by how the kernel fixmap page table is
1826 positioned, so this cannot be larger than 1GiB currently. Without
1827 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1828 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1829 modules area will shrink to compensate, up to the current maximum
1830 1GiB to 1GiB split. The default is 1GiB.
1832 If unsure, leave at the default value.
1834 # Relocation on x86 needs some additional build support
1835 config X86_NEED_RELOCS
1837 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1839 config PHYSICAL_ALIGN
1840 hex "Alignment value to which kernel should be aligned"
1842 range 0x2000 0x1000000 if X86_32
1843 range 0x200000 0x1000000 if X86_64
1845 This value puts the alignment restrictions on physical address
1846 where kernel is loaded and run from. Kernel is compiled for an
1847 address which meets above alignment restriction.
1849 If bootloader loads the kernel at a non-aligned address and
1850 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1851 address aligned to above value and run from there.
1853 If bootloader loads the kernel at a non-aligned address and
1854 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1855 load address and decompress itself to the address it has been
1856 compiled for and run from there. The address for which kernel is
1857 compiled already meets above alignment restrictions. Hence the
1858 end result is that kernel runs from a physical address meeting
1859 above alignment restrictions.
1861 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1862 this value must be a multiple of 0x200000.
1864 Don't change this unless you know what you are doing.
1867 bool "Support for hot-pluggable CPUs"
1870 Say Y here to allow turning CPUs off and on. CPUs can be
1871 controlled through /sys/devices/system/cpu.
1872 ( Note: power management support will enable this option
1873 automatically on SMP systems. )
1874 Say N if you want to disable CPU hotplug.
1876 config BOOTPARAM_HOTPLUG_CPU0
1877 bool "Set default setting of cpu0_hotpluggable"
1879 depends on HOTPLUG_CPU
1881 Set whether default state of cpu0_hotpluggable is on or off.
1883 Say Y here to enable CPU0 hotplug by default. If this switch
1884 is turned on, there is no need to give cpu0_hotplug kernel
1885 parameter and the CPU0 hotplug feature is enabled by default.
1887 Please note: there are two known CPU0 dependencies if you want
1888 to enable the CPU0 hotplug feature either by this switch or by
1889 cpu0_hotplug kernel parameter.
1891 First, resume from hibernate or suspend always starts from CPU0.
1892 So hibernate and suspend are prevented if CPU0 is offline.
1894 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1895 offline if any interrupt can not migrate out of CPU0. There may
1896 be other CPU0 dependencies.
1898 Please make sure the dependencies are under your control before
1899 you enable this feature.
1901 Say N if you don't want to enable CPU0 hotplug feature by default.
1902 You still can enable the CPU0 hotplug feature at boot by kernel
1903 parameter cpu0_hotplug.
1905 config DEBUG_HOTPLUG_CPU0
1907 prompt "Debug CPU0 hotplug"
1908 depends on HOTPLUG_CPU
1910 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1911 soon as possible and boots up userspace with CPU0 offlined. User
1912 can online CPU0 back after boot time.
1914 To debug CPU0 hotplug, you need to enable CPU0 offline/online
1915 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1916 compilation or giving cpu0_hotplug kernel parameter at boot.
1922 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
1923 depends on X86_32 || IA32_EMULATION
1925 Certain buggy versions of glibc will crash if they are
1926 presented with a 32-bit vDSO that is not mapped at the address
1927 indicated in its segment table.
1929 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
1930 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
1931 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
1932 the only released version with the bug, but OpenSUSE 9
1933 contains a buggy "glibc 2.3.2".
1935 The symptom of the bug is that everything crashes on startup, saying:
1936 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
1938 Saying Y here changes the default value of the vdso32 boot
1939 option from 1 to 0, which turns off the 32-bit vDSO entirely.
1940 This works around the glibc bug but hurts performance.
1942 If unsure, say N: if you are compiling your own kernel, you
1943 are unlikely to be using a buggy version of glibc.
1946 bool "Built-in kernel command line"
1948 Allow for specifying boot arguments to the kernel at
1949 build time. On some systems (e.g. embedded ones), it is
1950 necessary or convenient to provide some or all of the
1951 kernel boot arguments with the kernel itself (that is,
1952 to not rely on the boot loader to provide them.)
1954 To compile command line arguments into the kernel,
1955 set this option to 'Y', then fill in the
1956 the boot arguments in CONFIG_CMDLINE.
1958 Systems with fully functional boot loaders (i.e. non-embedded)
1959 should leave this option set to 'N'.
1962 string "Built-in kernel command string"
1963 depends on CMDLINE_BOOL
1966 Enter arguments here that should be compiled into the kernel
1967 image and used at boot time. If the boot loader provides a
1968 command line at boot time, it is appended to this string to
1969 form the full kernel command line, when the system boots.
1971 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1972 change this behavior.
1974 In most cases, the command line (whether built-in or provided
1975 by the boot loader) should specify the device for the root
1978 config CMDLINE_OVERRIDE
1979 bool "Built-in command line overrides boot loader arguments"
1980 depends on CMDLINE_BOOL
1982 Set this option to 'Y' to have the kernel ignore the boot loader
1983 command line, and use ONLY the built-in command line.
1985 This is used to work around broken boot loaders. This should
1986 be set to 'N' under normal conditions.
1990 config ARCH_ENABLE_MEMORY_HOTPLUG
1992 depends on X86_64 || (X86_32 && HIGHMEM)
1994 config ARCH_ENABLE_MEMORY_HOTREMOVE
1996 depends on MEMORY_HOTPLUG
1998 config USE_PERCPU_NUMA_NODE_ID
2002 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2004 depends on X86_64 || X86_PAE
2006 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2008 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2010 menu "Power management and ACPI options"
2012 config ARCH_HIBERNATION_HEADER
2014 depends on X86_64 && HIBERNATION
2016 source "kernel/power/Kconfig"
2018 source "drivers/acpi/Kconfig"
2020 source "drivers/sfi/Kconfig"
2027 tristate "APM (Advanced Power Management) BIOS support"
2028 depends on X86_32 && PM_SLEEP
2030 APM is a BIOS specification for saving power using several different
2031 techniques. This is mostly useful for battery powered laptops with
2032 APM compliant BIOSes. If you say Y here, the system time will be
2033 reset after a RESUME operation, the /proc/apm device will provide
2034 battery status information, and user-space programs will receive
2035 notification of APM "events" (e.g. battery status change).
2037 If you select "Y" here, you can disable actual use of the APM
2038 BIOS by passing the "apm=off" option to the kernel at boot time.
2040 Note that the APM support is almost completely disabled for
2041 machines with more than one CPU.
2043 In order to use APM, you will need supporting software. For location
2044 and more information, read <file:Documentation/power/apm-acpi.txt>
2045 and the Battery Powered Linux mini-HOWTO, available from
2046 <http://www.tldp.org/docs.html#howto>.
2048 This driver does not spin down disk drives (see the hdparm(8)
2049 manpage ("man 8 hdparm") for that), and it doesn't turn off
2050 VESA-compliant "green" monitors.
2052 This driver does not support the TI 4000M TravelMate and the ACER
2053 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2054 desktop machines also don't have compliant BIOSes, and this driver
2055 may cause those machines to panic during the boot phase.
2057 Generally, if you don't have a battery in your machine, there isn't
2058 much point in using this driver and you should say N. If you get
2059 random kernel OOPSes or reboots that don't seem to be related to
2060 anything, try disabling/enabling this option (or disabling/enabling
2063 Some other things you should try when experiencing seemingly random,
2066 1) make sure that you have enough swap space and that it is
2068 2) pass the "no-hlt" option to the kernel
2069 3) switch on floating point emulation in the kernel and pass
2070 the "no387" option to the kernel
2071 4) pass the "floppy=nodma" option to the kernel
2072 5) pass the "mem=4M" option to the kernel (thereby disabling
2073 all but the first 4 MB of RAM)
2074 6) make sure that the CPU is not over clocked.
2075 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2076 8) disable the cache from your BIOS settings
2077 9) install a fan for the video card or exchange video RAM
2078 10) install a better fan for the CPU
2079 11) exchange RAM chips
2080 12) exchange the motherboard.
2082 To compile this driver as a module, choose M here: the
2083 module will be called apm.
2087 config APM_IGNORE_USER_SUSPEND
2088 bool "Ignore USER SUSPEND"
2090 This option will ignore USER SUSPEND requests. On machines with a
2091 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2092 series notebooks, it is necessary to say Y because of a BIOS bug.
2094 config APM_DO_ENABLE
2095 bool "Enable PM at boot time"
2097 Enable APM features at boot time. From page 36 of the APM BIOS
2098 specification: "When disabled, the APM BIOS does not automatically
2099 power manage devices, enter the Standby State, enter the Suspend
2100 State, or take power saving steps in response to CPU Idle calls."
2101 This driver will make CPU Idle calls when Linux is idle (unless this
2102 feature is turned off -- see "Do CPU IDLE calls", below). This
2103 should always save battery power, but more complicated APM features
2104 will be dependent on your BIOS implementation. You may need to turn
2105 this option off if your computer hangs at boot time when using APM
2106 support, or if it beeps continuously instead of suspending. Turn
2107 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2108 T400CDT. This is off by default since most machines do fine without
2113 bool "Make CPU Idle calls when idle"
2115 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2116 On some machines, this can activate improved power savings, such as
2117 a slowed CPU clock rate, when the machine is idle. These idle calls
2118 are made after the idle loop has run for some length of time (e.g.,
2119 333 mS). On some machines, this will cause a hang at boot time or
2120 whenever the CPU becomes idle. (On machines with more than one CPU,
2121 this option does nothing.)
2123 config APM_DISPLAY_BLANK
2124 bool "Enable console blanking using APM"
2126 Enable console blanking using the APM. Some laptops can use this to
2127 turn off the LCD backlight when the screen blanker of the Linux
2128 virtual console blanks the screen. Note that this is only used by
2129 the virtual console screen blanker, and won't turn off the backlight
2130 when using the X Window system. This also doesn't have anything to
2131 do with your VESA-compliant power-saving monitor. Further, this
2132 option doesn't work for all laptops -- it might not turn off your
2133 backlight at all, or it might print a lot of errors to the console,
2134 especially if you are using gpm.
2136 config APM_ALLOW_INTS
2137 bool "Allow interrupts during APM BIOS calls"
2139 Normally we disable external interrupts while we are making calls to
2140 the APM BIOS as a measure to lessen the effects of a badly behaving
2141 BIOS implementation. The BIOS should reenable interrupts if it
2142 needs to. Unfortunately, some BIOSes do not -- especially those in
2143 many of the newer IBM Thinkpads. If you experience hangs when you
2144 suspend, try setting this to Y. Otherwise, say N.
2148 source "drivers/cpufreq/Kconfig"
2150 source "drivers/cpuidle/Kconfig"
2152 source "drivers/idle/Kconfig"
2157 menu "Bus options (PCI etc.)"
2163 Find out whether you have a PCI motherboard. PCI is the name of a
2164 bus system, i.e. the way the CPU talks to the other stuff inside
2165 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2166 VESA. If you have PCI, say Y, otherwise N.
2169 prompt "PCI access mode"
2170 depends on X86_32 && PCI
2173 On PCI systems, the BIOS can be used to detect the PCI devices and
2174 determine their configuration. However, some old PCI motherboards
2175 have BIOS bugs and may crash if this is done. Also, some embedded
2176 PCI-based systems don't have any BIOS at all. Linux can also try to
2177 detect the PCI hardware directly without using the BIOS.
2179 With this option, you can specify how Linux should detect the
2180 PCI devices. If you choose "BIOS", the BIOS will be used,
2181 if you choose "Direct", the BIOS won't be used, and if you
2182 choose "MMConfig", then PCI Express MMCONFIG will be used.
2183 If you choose "Any", the kernel will try MMCONFIG, then the
2184 direct access method and falls back to the BIOS if that doesn't
2185 work. If unsure, go with the default, which is "Any".
2190 config PCI_GOMMCONFIG
2207 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2209 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2212 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2216 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2220 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2224 depends on PCI && XEN
2232 bool "Support mmconfig PCI config space access"
2233 depends on X86_64 && PCI && ACPI
2235 config PCI_CNB20LE_QUIRK
2236 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2239 Read the PCI windows out of the CNB20LE host bridge. This allows
2240 PCI hotplug to work on systems with the CNB20LE chipset which do
2243 There's no public spec for this chipset, and this functionality
2244 is known to be incomplete.
2246 You should say N unless you know you need this.
2248 source "drivers/pci/pcie/Kconfig"
2250 source "drivers/pci/Kconfig"
2252 # x86_64 have no ISA slots, but can have ISA-style DMA.
2254 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2257 Enables ISA-style DMA support for devices requiring such controllers.
2265 Find out whether you have ISA slots on your motherboard. ISA is the
2266 name of a bus system, i.e. the way the CPU talks to the other stuff
2267 inside your box. Other bus systems are PCI, EISA, MicroChannel
2268 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2269 newer boards don't support it. If you have ISA, say Y, otherwise N.
2275 The Extended Industry Standard Architecture (EISA) bus was
2276 developed as an open alternative to the IBM MicroChannel bus.
2278 The EISA bus provided some of the features of the IBM MicroChannel
2279 bus while maintaining backward compatibility with cards made for
2280 the older ISA bus. The EISA bus saw limited use between 1988 and
2281 1995 when it was made obsolete by the PCI bus.
2283 Say Y here if you are building a kernel for an EISA-based machine.
2287 source "drivers/eisa/Kconfig"
2290 tristate "NatSemi SCx200 support"
2292 This provides basic support for National Semiconductor's
2293 (now AMD's) Geode processors. The driver probes for the
2294 PCI-IDs of several on-chip devices, so its a good dependency
2295 for other scx200_* drivers.
2297 If compiled as a module, the driver is named scx200.
2299 config SCx200HR_TIMER
2300 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2304 This driver provides a clocksource built upon the on-chip
2305 27MHz high-resolution timer. Its also a workaround for
2306 NSC Geode SC-1100's buggy TSC, which loses time when the
2307 processor goes idle (as is done by the scheduler). The
2308 other workaround is idle=poll boot option.
2311 bool "One Laptop Per Child support"
2318 Add support for detecting the unique features of the OLPC
2322 bool "OLPC XO-1 Power Management"
2323 depends on OLPC && MFD_CS5535 && PM_SLEEP
2326 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2329 bool "OLPC XO-1 Real Time Clock"
2330 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2332 Add support for the XO-1 real time clock, which can be used as a
2333 programmable wakeup source.
2336 bool "OLPC XO-1 SCI extras"
2337 depends on OLPC && OLPC_XO1_PM
2343 Add support for SCI-based features of the OLPC XO-1 laptop:
2344 - EC-driven system wakeups
2348 - AC adapter status updates
2349 - Battery status updates
2351 config OLPC_XO15_SCI
2352 bool "OLPC XO-1.5 SCI extras"
2353 depends on OLPC && ACPI
2356 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2357 - EC-driven system wakeups
2358 - AC adapter status updates
2359 - Battery status updates
2362 bool "PCEngines ALIX System Support (LED setup)"
2365 This option enables system support for the PCEngines ALIX.
2366 At present this just sets up LEDs for GPIO control on
2367 ALIX2/3/6 boards. However, other system specific setup should
2370 Note: You must still enable the drivers for GPIO and LED support
2371 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2373 Note: You have to set alix.force=1 for boards with Award BIOS.
2376 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2379 This option enables system support for the Soekris Engineering net5501.
2382 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2386 This option enables system support for the Traverse Technologies GEOS.
2389 bool "Technologic Systems TS-5500 platform support"
2391 select CHECK_SIGNATURE
2395 This option enables system support for the Technologic Systems TS-5500.
2401 depends on CPU_SUP_AMD && PCI
2403 source "drivers/pcmcia/Kconfig"
2405 source "drivers/pci/hotplug/Kconfig"
2408 tristate "RapidIO support"
2412 If enabled this option will include drivers and the core
2413 infrastructure code to support RapidIO interconnect devices.
2415 source "drivers/rapidio/Kconfig"
2418 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2420 Firmwares often provide initial graphics framebuffers so the BIOS,
2421 bootloader or kernel can show basic video-output during boot for
2422 user-guidance and debugging. Historically, x86 used the VESA BIOS
2423 Extensions and EFI-framebuffers for this, which are mostly limited
2425 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2426 framebuffers so the new generic system-framebuffer drivers can be
2427 used on x86. If the framebuffer is not compatible with the generic
2428 modes, it is adverticed as fallback platform framebuffer so legacy
2429 drivers like efifb, vesafb and uvesafb can pick it up.
2430 If this option is not selected, all system framebuffers are always
2431 marked as fallback platform framebuffers as usual.
2433 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2434 not be able to pick up generic system framebuffers if this option
2435 is selected. You are highly encouraged to enable simplefb as
2436 replacement if you select this option. simplefb can correctly deal
2437 with generic system framebuffers. But you should still keep vesafb
2438 and others enabled as fallback if a system framebuffer is
2439 incompatible with simplefb.
2446 menu "Executable file formats / Emulations"
2448 source "fs/Kconfig.binfmt"
2450 config IA32_EMULATION
2451 bool "IA32 Emulation"
2454 select COMPAT_BINFMT_ELF
2457 Include code to run legacy 32-bit programs under a
2458 64-bit kernel. You should likely turn this on, unless you're
2459 100% sure that you don't have any 32-bit programs left.
2462 tristate "IA32 a.out support"
2463 depends on IA32_EMULATION
2465 Support old a.out binaries in the 32bit emulation.
2468 bool "x32 ABI for 64-bit mode"
2469 depends on X86_64 && IA32_EMULATION
2471 Include code to run binaries for the x32 native 32-bit ABI
2472 for 64-bit processors. An x32 process gets access to the
2473 full 64-bit register file and wide data path while leaving
2474 pointers at 32 bits for smaller memory footprint.
2476 You will need a recent binutils (2.22 or later) with
2477 elf32_x86_64 support enabled to compile a kernel with this
2482 depends on IA32_EMULATION || X86_X32
2483 select ARCH_WANT_OLD_COMPAT_IPC
2486 config COMPAT_FOR_U64_ALIGNMENT
2489 config SYSVIPC_COMPAT
2501 config HAVE_ATOMIC_IOMAP
2505 config X86_DEV_DMA_OPS
2507 depends on X86_64 || STA2X11
2509 config X86_DMA_REMAP
2517 source "net/Kconfig"
2519 source "drivers/Kconfig"
2521 source "drivers/firmware/Kconfig"
2525 source "arch/x86/Kconfig.debug"
2527 source "security/Kconfig"
2529 source "crypto/Kconfig"
2531 source "arch/x86/kvm/Kconfig"
2533 source "lib/Kconfig"