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_HAS_GCOV_PROFILE_ALL
28 select ARCH_MIGHT_HAVE_PC_PARPORT
29 select ARCH_MIGHT_HAVE_PC_SERIO
30 select HAVE_AOUT if X86_32
31 select HAVE_UNSTABLE_SCHED_CLOCK
32 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
33 select ARCH_SUPPORTS_INT128 if X86_64
36 select HAVE_PCSPKR_PLATFORM
37 select HAVE_PERF_EVENTS
38 select HAVE_IOREMAP_PROT
41 select HAVE_MEMBLOCK_NODE_MAP
42 select ARCH_DISCARD_MEMBLOCK
43 select ARCH_WANT_OPTIONAL_GPIOLIB
44 select ARCH_WANT_FRAME_POINTERS
46 select HAVE_DMA_CONTIGUOUS
47 select HAVE_KRETPROBES
48 select GENERIC_EARLY_IOREMAP
50 select HAVE_KPROBES_ON_FTRACE
51 select HAVE_FTRACE_MCOUNT_RECORD
52 select HAVE_FENTRY if X86_64
53 select HAVE_C_RECORDMCOUNT
54 select HAVE_DYNAMIC_FTRACE
55 select HAVE_DYNAMIC_FTRACE_WITH_REGS
56 select HAVE_FUNCTION_TRACER
57 select HAVE_FUNCTION_GRAPH_TRACER
58 select HAVE_FUNCTION_GRAPH_FP_TEST
59 select HAVE_SYSCALL_TRACEPOINTS
60 select SYSCTL_EXCEPTION_TRACE
63 select HAVE_ARCH_TRACEHOOK
64 select HAVE_GENERIC_DMA_COHERENT if X86_32
65 select HAVE_EFFICIENT_UNALIGNED_ACCESS
66 select USER_STACKTRACE_SUPPORT
67 select HAVE_REGS_AND_STACK_ACCESS_API
68 select HAVE_DMA_API_DEBUG
69 select HAVE_KERNEL_GZIP
70 select HAVE_KERNEL_BZIP2
71 select HAVE_KERNEL_LZMA
73 select HAVE_KERNEL_LZO
74 select HAVE_KERNEL_LZ4
75 select HAVE_HW_BREAKPOINT
76 select HAVE_MIXED_BREAKPOINTS_REGS
78 select HAVE_PERF_EVENTS_NMI
80 select HAVE_PERF_USER_STACK_DUMP
81 select HAVE_DEBUG_KMEMLEAK
83 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
84 select HAVE_CMPXCHG_LOCAL
85 select HAVE_CMPXCHG_DOUBLE
86 select HAVE_ARCH_KMEMCHECK
87 select HAVE_USER_RETURN_NOTIFIER
88 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
89 select HAVE_ARCH_JUMP_LABEL
90 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
92 select GENERIC_FIND_FIRST_BIT
93 select GENERIC_IRQ_PROBE
94 select GENERIC_PENDING_IRQ if SMP
95 select GENERIC_IRQ_SHOW
96 select GENERIC_CLOCKEVENTS_MIN_ADJUST
97 select IRQ_FORCED_THREADING
98 select HAVE_BPF_JIT if X86_64
99 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
100 select ARCH_HAS_SG_CHAIN
102 select ARCH_HAVE_NMI_SAFE_CMPXCHG
104 select DCACHE_WORD_ACCESS
105 select GENERIC_SMP_IDLE_THREAD
106 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
107 select HAVE_ARCH_SECCOMP_FILTER
108 select BUILDTIME_EXTABLE_SORT
109 select GENERIC_CMOS_UPDATE
110 select HAVE_ARCH_SOFT_DIRTY if X86_64
111 select CLOCKSOURCE_WATCHDOG
112 select GENERIC_CLOCKEVENTS
113 select ARCH_CLOCKSOURCE_DATA
114 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
115 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
116 select GENERIC_TIME_VSYSCALL
117 select GENERIC_STRNCPY_FROM_USER
118 select GENERIC_STRNLEN_USER
119 select HAVE_CONTEXT_TRACKING if X86_64
120 select HAVE_IRQ_TIME_ACCOUNTING
122 select MODULES_USE_ELF_REL if X86_32
123 select MODULES_USE_ELF_RELA if X86_64
124 select CLONE_BACKWARDS if X86_32
125 select ARCH_USE_BUILTIN_BSWAP
126 select ARCH_USE_QUEUE_RWLOCK
127 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
128 select OLD_SIGACTION if X86_32
129 select COMPAT_OLD_SIGACTION if IA32_EMULATION
131 select HAVE_DEBUG_STACKOVERFLOW
132 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
133 select HAVE_CC_STACKPROTECTOR
134 select GENERIC_CPU_AUTOPROBE
135 select HAVE_ARCH_AUDITSYSCALL
136 select ARCH_SUPPORTS_ATOMIC_RMW
137 select HAVE_ACPI_APEI if ACPI
138 select HAVE_ACPI_APEI_NMI if ACPI
139 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
140 select X86_FEATURE_NAMES if PROC_FS
142 config INSTRUCTION_DECODER
144 depends on KPROBES || PERF_EVENTS || UPROBES
146 config PERF_EVENTS_INTEL_UNCORE
148 depends on PERF_EVENTS && CPU_SUP_INTEL && PCI
152 default "elf32-i386" if X86_32
153 default "elf64-x86-64" if X86_64
155 config ARCH_DEFCONFIG
157 default "arch/x86/configs/i386_defconfig" if X86_32
158 default "arch/x86/configs/x86_64_defconfig" if X86_64
160 config LOCKDEP_SUPPORT
163 config STACKTRACE_SUPPORT
166 config HAVE_LATENCYTOP_SUPPORT
175 config NEED_DMA_MAP_STATE
177 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
179 config NEED_SG_DMA_LENGTH
182 config GENERIC_ISA_DMA
184 depends on ISA_DMA_API
189 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
191 config GENERIC_BUG_RELATIVE_POINTERS
194 config GENERIC_HWEIGHT
197 config ARCH_MAY_HAVE_PC_FDC
199 depends on ISA_DMA_API
201 config RWSEM_XCHGADD_ALGORITHM
204 config GENERIC_CALIBRATE_DELAY
207 config ARCH_HAS_CPU_RELAX
210 config ARCH_HAS_CACHE_LINE_SIZE
213 config HAVE_SETUP_PER_CPU_AREA
216 config NEED_PER_CPU_EMBED_FIRST_CHUNK
219 config NEED_PER_CPU_PAGE_FIRST_CHUNK
222 config ARCH_HIBERNATION_POSSIBLE
225 config ARCH_SUSPEND_POSSIBLE
228 config ARCH_WANT_HUGE_PMD_SHARE
231 config ARCH_WANT_GENERAL_HUGETLB
242 config ARCH_SUPPORTS_OPTIMIZED_INLINING
245 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
248 config HAVE_INTEL_TXT
250 depends on INTEL_IOMMU && ACPI
254 depends on CPU_SUP_INTEL
258 depends on X86_32 && SMP
262 depends on X86_64 && SMP
268 config X86_32_LAZY_GS
270 depends on X86_32 && !CC_STACKPROTECTOR
272 config ARCH_HWEIGHT_CFLAGS
274 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
275 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
277 config ARCH_SUPPORTS_UPROBES
280 config FIX_EARLYCON_MEM
283 source "init/Kconfig"
284 source "kernel/Kconfig.freezer"
286 menu "Processor type and features"
289 bool "DMA memory allocation support" if EXPERT
292 DMA memory allocation support allows devices with less than 32-bit
293 addressing to allocate within the first 16MB of address space.
294 Disable if no such devices will be used.
299 bool "Symmetric multi-processing support"
301 This enables support for systems with more than one CPU. If you have
302 a system with only one CPU, say N. If you have a system with more
305 If you say N here, the kernel will run on uni- and multiprocessor
306 machines, but will use only one CPU of a multiprocessor machine. If
307 you say Y here, the kernel will run on many, but not all,
308 uniprocessor machines. On a uniprocessor machine, the kernel
309 will run faster if you say N here.
311 Note that if you say Y here and choose architecture "586" or
312 "Pentium" under "Processor family", the kernel will not work on 486
313 architectures. Similarly, multiprocessor kernels for the "PPro"
314 architecture may not work on all Pentium based boards.
316 People using multiprocessor machines who say Y here should also say
317 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
318 Management" code will be disabled if you say Y here.
320 See also <file:Documentation/x86/i386/IO-APIC.txt>,
321 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
322 <http://www.tldp.org/docs.html#howto>.
324 If you don't know what to do here, say N.
326 config X86_FEATURE_NAMES
327 bool "Processor feature human-readable names" if EMBEDDED
330 This option compiles in a table of x86 feature bits and corresponding
331 names. This is required to support /proc/cpuinfo and a few kernel
332 messages. You can disable this to save space, at the expense of
333 making those few kernel messages show numeric feature bits instead.
338 bool "Support x2apic"
339 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
341 This enables x2apic support on CPUs that have this feature.
343 This allows 32-bit apic IDs (so it can support very large systems),
344 and accesses the local apic via MSRs not via mmio.
346 If you don't know what to do here, say N.
349 bool "Enable MPS table" if ACPI || SFI
351 depends on X86_LOCAL_APIC
353 For old smp systems that do not have proper acpi support. Newer systems
354 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
357 bool "Support for big SMP systems with more than 8 CPUs"
358 depends on X86_32 && SMP
360 This option is needed for the systems that have more than 8 CPUs
364 depends on X86_GOLDFISH
367 config X86_EXTENDED_PLATFORM
368 bool "Support for extended (non-PC) x86 platforms"
371 If you disable this option then the kernel will only support
372 standard PC platforms. (which covers the vast majority of
375 If you enable this option then you'll be able to select support
376 for the following (non-PC) 32 bit x86 platforms:
377 Goldfish (Android emulator)
380 SGI 320/540 (Visual Workstation)
381 STA2X11-based (e.g. Northville)
382 Moorestown MID devices
384 If you have one of these systems, or if you want to build a
385 generic distribution kernel, say Y here - otherwise say N.
389 config X86_EXTENDED_PLATFORM
390 bool "Support for extended (non-PC) x86 platforms"
393 If you disable this option then the kernel will only support
394 standard PC platforms. (which covers the vast majority of
397 If you enable this option then you'll be able to select support
398 for the following (non-PC) 64 bit x86 platforms:
403 If you have one of these systems, or if you want to build a
404 generic distribution kernel, say Y here - otherwise say N.
406 # This is an alphabetically sorted list of 64 bit extended platforms
407 # Please maintain the alphabetic order if and when there are additions
409 bool "Numascale NumaChip"
411 depends on X86_EXTENDED_PLATFORM
414 depends on X86_X2APIC
415 depends on PCI_MMCONFIG
417 Adds support for Numascale NumaChip large-SMP systems. Needed to
418 enable more than ~168 cores.
419 If you don't have one of these, you should say N here.
423 select HYPERVISOR_GUEST
425 depends on X86_64 && PCI
426 depends on X86_EXTENDED_PLATFORM
429 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
430 supposed to run on these EM64T-based machines. Only choose this option
431 if you have one of these machines.
434 bool "SGI Ultraviolet"
436 depends on X86_EXTENDED_PLATFORM
438 depends on X86_X2APIC
440 This option is needed in order to support SGI Ultraviolet systems.
441 If you don't have one of these, you should say N here.
443 # Following is an alphabetically sorted list of 32 bit extended platforms
444 # Please maintain the alphabetic order if and when there are additions
447 bool "Goldfish (Virtual Platform)"
448 depends on X86_EXTENDED_PLATFORM
450 Enable support for the Goldfish virtual platform used primarily
451 for Android development. Unless you are building for the Android
452 Goldfish emulator say N here.
455 bool "CE4100 TV platform"
457 depends on PCI_GODIRECT
458 depends on X86_IO_APIC
460 depends on X86_EXTENDED_PLATFORM
461 select X86_REBOOTFIXUPS
463 select OF_EARLY_FLATTREE
466 Select for the Intel CE media processor (CE4100) SOC.
467 This option compiles in support for the CE4100 SOC for settop
468 boxes and media devices.
471 bool "Intel MID platform support"
473 depends on X86_EXTENDED_PLATFORM
474 depends on X86_PLATFORM_DEVICES
477 depends on X86_IO_APIC
483 select MFD_INTEL_MSIC
485 Select to build a kernel capable of supporting Intel MID (Mobile
486 Internet Device) platform systems which do not have the PCI legacy
487 interfaces. If you are building for a PC class system say N here.
489 Intel MID platforms are based on an Intel processor and chipset which
490 consume less power than most of the x86 derivatives.
492 config X86_INTEL_LPSS
493 bool "Intel Low Power Subsystem Support"
498 Select to build support for Intel Low Power Subsystem such as
499 found on Intel Lynxpoint PCH. Selecting this option enables
500 things like clock tree (common clock framework) and pincontrol
501 which are needed by the LPSS peripheral drivers.
504 tristate "Intel SoC IOSF Sideband support for SoC platforms"
507 This option enables sideband register access support for Intel SoC
508 platforms. On these platforms the IOSF sideband is used in lieu of
509 MSR's for some register accesses, mostly but not limited to thermal
510 and power. Drivers may query the availability of this device to
511 determine if they need the sideband in order to work on these
512 platforms. The sideband is available on the following SoC products.
513 This list is not meant to be exclusive.
518 You should say Y if you are running a kernel on one of these SoC's.
520 config IOSF_MBI_DEBUG
521 bool "Enable IOSF sideband access through debugfs"
522 depends on IOSF_MBI && DEBUG_FS
524 Select this option to expose the IOSF sideband access registers (MCR,
525 MDR, MCRX) through debugfs to write and read register information from
526 different units on the SoC. This is most useful for obtaining device
527 state information for debug and analysis. As this is a general access
528 mechanism, users of this option would have specific knowledge of the
529 device they want to access.
531 If you don't require the option or are in doubt, say N.
534 bool "RDC R-321x SoC"
536 depends on X86_EXTENDED_PLATFORM
538 select X86_REBOOTFIXUPS
540 This option is needed for RDC R-321x system-on-chip, also known
542 If you don't have one of these chips, you should say N here.
544 config X86_32_NON_STANDARD
545 bool "Support non-standard 32-bit SMP architectures"
546 depends on X86_32 && SMP
547 depends on X86_EXTENDED_PLATFORM
549 This option compiles in the bigsmp and STA2X11 default
550 subarchitectures. It is intended for a generic binary
551 kernel. If you select them all, kernel will probe it one by
552 one and will fallback to default.
554 # Alphabetically sorted list of Non standard 32 bit platforms
556 config X86_SUPPORTS_MEMORY_FAILURE
558 # MCE code calls memory_failure():
560 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
561 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
562 depends on X86_64 || !SPARSEMEM
563 select ARCH_SUPPORTS_MEMORY_FAILURE
566 bool "STA2X11 Companion Chip Support"
567 depends on X86_32_NON_STANDARD && PCI
568 select X86_DEV_DMA_OPS
572 select ARCH_REQUIRE_GPIOLIB
575 This adds support for boards based on the STA2X11 IO-Hub,
576 a.k.a. "ConneXt". The chip is used in place of the standard
577 PC chipset, so all "standard" peripherals are missing. If this
578 option is selected the kernel will still be able to boot on
579 standard PC machines.
582 tristate "Eurobraille/Iris poweroff module"
585 The Iris machines from EuroBraille do not have APM or ACPI support
586 to shut themselves down properly. A special I/O sequence is
587 needed to do so, which is what this module does at
590 This is only for Iris machines from EuroBraille.
594 config SCHED_OMIT_FRAME_POINTER
596 prompt "Single-depth WCHAN output"
599 Calculate simpler /proc/<PID>/wchan values. If this option
600 is disabled then wchan values will recurse back to the
601 caller function. This provides more accurate wchan values,
602 at the expense of slightly more scheduling overhead.
604 If in doubt, say "Y".
606 menuconfig HYPERVISOR_GUEST
607 bool "Linux guest support"
609 Say Y here to enable options for running Linux under various hyper-
610 visors. This option enables basic hypervisor detection and platform
613 If you say N, all options in this submenu will be skipped and
614 disabled, and Linux guest support won't be built in.
619 bool "Enable paravirtualization code"
621 This changes the kernel so it can modify itself when it is run
622 under a hypervisor, potentially improving performance significantly
623 over full virtualization. However, when run without a hypervisor
624 the kernel is theoretically slower and slightly larger.
626 config PARAVIRT_DEBUG
627 bool "paravirt-ops debugging"
628 depends on PARAVIRT && DEBUG_KERNEL
630 Enable to debug paravirt_ops internals. Specifically, BUG if
631 a paravirt_op is missing when it is called.
633 config PARAVIRT_SPINLOCKS
634 bool "Paravirtualization layer for spinlocks"
635 depends on PARAVIRT && SMP
636 select UNINLINE_SPIN_UNLOCK
638 Paravirtualized spinlocks allow a pvops backend to replace the
639 spinlock implementation with something virtualization-friendly
640 (for example, block the virtual CPU rather than spinning).
642 It has a minimal impact on native kernels and gives a nice performance
643 benefit on paravirtualized KVM / Xen kernels.
645 If you are unsure how to answer this question, answer Y.
647 source "arch/x86/xen/Kconfig"
650 bool "KVM Guest support (including kvmclock)"
652 select PARAVIRT_CLOCK
655 This option enables various optimizations for running under the KVM
656 hypervisor. It includes a paravirtualized clock, so that instead
657 of relying on a PIT (or probably other) emulation by the
658 underlying device model, the host provides the guest with
659 timing infrastructure such as time of day, and system time
662 bool "Enable debug information for KVM Guests in debugfs"
663 depends on KVM_GUEST && DEBUG_FS
666 This option enables collection of various statistics for KVM guest.
667 Statistics are displayed in debugfs filesystem. Enabling this option
668 may incur significant overhead.
670 source "arch/x86/lguest/Kconfig"
672 config PARAVIRT_TIME_ACCOUNTING
673 bool "Paravirtual steal time accounting"
677 Select this option to enable fine granularity task steal time
678 accounting. Time spent executing other tasks in parallel with
679 the current vCPU is discounted from the vCPU power. To account for
680 that, there can be a small performance impact.
682 If in doubt, say N here.
684 config PARAVIRT_CLOCK
687 endif #HYPERVISOR_GUEST
695 This option adds a kernel parameter 'memtest', which allows memtest
697 memtest=0, mean disabled; -- default
698 memtest=1, mean do 1 test pattern;
700 memtest=4, mean do 4 test patterns.
701 If you are unsure how to answer this question, answer N.
703 source "arch/x86/Kconfig.cpu"
707 prompt "HPET Timer Support" if X86_32
709 Use the IA-PC HPET (High Precision Event Timer) to manage
710 time in preference to the PIT and RTC, if a HPET is
712 HPET is the next generation timer replacing legacy 8254s.
713 The HPET provides a stable time base on SMP
714 systems, unlike the TSC, but it is more expensive to access,
715 as it is off-chip. You can find the HPET spec at
716 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
718 You can safely choose Y here. However, HPET will only be
719 activated if the platform and the BIOS support this feature.
720 Otherwise the 8254 will be used for timing services.
722 Choose N to continue using the legacy 8254 timer.
724 config HPET_EMULATE_RTC
726 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
729 def_bool y if X86_INTEL_MID
730 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
732 depends on X86_INTEL_MID && SFI
734 APB timer is the replacement for 8254, HPET on X86 MID platforms.
735 The APBT provides a stable time base on SMP
736 systems, unlike the TSC, but it is more expensive to access,
737 as it is off-chip. APB timers are always running regardless of CPU
738 C states, they are used as per CPU clockevent device when possible.
740 # Mark as expert because too many people got it wrong.
741 # The code disables itself when not needed.
744 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
745 bool "Enable DMI scanning" if EXPERT
747 Enabled scanning of DMI to identify machine quirks. Say Y
748 here unless you have verified that your setup is not
749 affected by entries in the DMI blacklist. Required by PNP
753 bool "Old AMD GART IOMMU support"
755 depends on X86_64 && PCI && AMD_NB
757 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
758 GART based hardware IOMMUs.
760 The GART supports full DMA access for devices with 32-bit access
761 limitations, on systems with more than 3 GB. This is usually needed
762 for USB, sound, many IDE/SATA chipsets and some other devices.
764 Newer systems typically have a modern AMD IOMMU, supported via
765 the CONFIG_AMD_IOMMU=y config option.
767 In normal configurations this driver is only active when needed:
768 there's more than 3 GB of memory and the system contains a
769 32-bit limited device.
774 bool "IBM Calgary IOMMU support"
776 depends on X86_64 && PCI
778 Support for hardware IOMMUs in IBM's xSeries x366 and x460
779 systems. Needed to run systems with more than 3GB of memory
780 properly with 32-bit PCI devices that do not support DAC
781 (Double Address Cycle). Calgary also supports bus level
782 isolation, where all DMAs pass through the IOMMU. This
783 prevents them from going anywhere except their intended
784 destination. This catches hard-to-find kernel bugs and
785 mis-behaving drivers and devices that do not use the DMA-API
786 properly to set up their DMA buffers. The IOMMU can be
787 turned off at boot time with the iommu=off parameter.
788 Normally the kernel will make the right choice by itself.
791 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
793 prompt "Should Calgary be enabled by default?"
794 depends on CALGARY_IOMMU
796 Should Calgary be enabled by default? if you choose 'y', Calgary
797 will be used (if it exists). If you choose 'n', Calgary will not be
798 used even if it exists. If you choose 'n' and would like to use
799 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
802 # need this always selected by IOMMU for the VIA workaround
806 Support for software bounce buffers used on x86-64 systems
807 which don't have a hardware IOMMU. Using this PCI devices
808 which can only access 32-bits of memory can be used on systems
809 with more than 3 GB of memory.
814 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
817 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
818 depends on X86_64 && SMP && DEBUG_KERNEL
819 select CPUMASK_OFFSTACK
821 Enable maximum number of CPUS and NUMA Nodes for this architecture.
825 int "Maximum number of CPUs" if SMP && !MAXSMP
826 range 2 8 if SMP && X86_32 && !X86_BIGSMP
827 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
828 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
830 default "8192" if MAXSMP
831 default "32" if SMP && X86_BIGSMP
834 This allows you to specify the maximum number of CPUs which this
835 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
836 supported value is 4096, otherwise the maximum value is 512. The
837 minimum value which makes sense is 2.
839 This is purely to save memory - each supported CPU adds
840 approximately eight kilobytes to the kernel image.
843 bool "SMT (Hyperthreading) scheduler support"
846 SMT scheduler support improves the CPU scheduler's decision making
847 when dealing with Intel Pentium 4 chips with HyperThreading at a
848 cost of slightly increased overhead in some places. If unsure say
853 prompt "Multi-core scheduler support"
856 Multi-core scheduler support improves the CPU scheduler's decision
857 making when dealing with multi-core CPU chips at a cost of slightly
858 increased overhead in some places. If unsure say N here.
860 source "kernel/Kconfig.preempt"
863 bool "Local APIC support on uniprocessors"
864 depends on X86_32 && !SMP && !X86_32_NON_STANDARD && !PCI_MSI
866 A local APIC (Advanced Programmable Interrupt Controller) is an
867 integrated interrupt controller in the CPU. If you have a single-CPU
868 system which has a processor with a local APIC, you can say Y here to
869 enable and use it. If you say Y here even though your machine doesn't
870 have a local APIC, then the kernel will still run with no slowdown at
871 all. The local APIC supports CPU-generated self-interrupts (timer,
872 performance counters), and the NMI watchdog which detects hard
876 bool "IO-APIC support on uniprocessors"
877 depends on X86_UP_APIC
879 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
880 SMP-capable replacement for PC-style interrupt controllers. Most
881 SMP systems and many recent uniprocessor systems have one.
883 If you have a single-CPU system with an IO-APIC, you can say Y here
884 to use it. If you say Y here even though your machine doesn't have
885 an IO-APIC, then the kernel will still run with no slowdown at all.
887 config X86_LOCAL_APIC
889 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
893 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC || PCI_MSI
894 select GENERIC_IRQ_LEGACY_ALLOC_HWIRQ
897 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
898 bool "Reroute for broken boot IRQs"
899 depends on X86_IO_APIC
901 This option enables a workaround that fixes a source of
902 spurious interrupts. This is recommended when threaded
903 interrupt handling is used on systems where the generation of
904 superfluous "boot interrupts" cannot be disabled.
906 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
907 entry in the chipset's IO-APIC is masked (as, e.g. the RT
908 kernel does during interrupt handling). On chipsets where this
909 boot IRQ generation cannot be disabled, this workaround keeps
910 the original IRQ line masked so that only the equivalent "boot
911 IRQ" is delivered to the CPUs. The workaround also tells the
912 kernel to set up the IRQ handler on the boot IRQ line. In this
913 way only one interrupt is delivered to the kernel. Otherwise
914 the spurious second interrupt may cause the kernel to bring
915 down (vital) interrupt lines.
917 Only affects "broken" chipsets. Interrupt sharing may be
918 increased on these systems.
921 bool "Machine Check / overheating reporting"
924 Machine Check support allows the processor to notify the
925 kernel if it detects a problem (e.g. overheating, data corruption).
926 The action the kernel takes depends on the severity of the problem,
927 ranging from warning messages to halting the machine.
931 prompt "Intel MCE features"
932 depends on X86_MCE && X86_LOCAL_APIC
934 Additional support for intel specific MCE features such as
939 prompt "AMD MCE features"
940 depends on X86_MCE && X86_LOCAL_APIC
942 Additional support for AMD specific MCE features such as
943 the DRAM Error Threshold.
945 config X86_ANCIENT_MCE
946 bool "Support for old Pentium 5 / WinChip machine checks"
947 depends on X86_32 && X86_MCE
949 Include support for machine check handling on old Pentium 5 or WinChip
950 systems. These typically need to be enabled explicitly on the command
953 config X86_MCE_THRESHOLD
954 depends on X86_MCE_AMD || X86_MCE_INTEL
957 config X86_MCE_INJECT
959 tristate "Machine check injector support"
961 Provide support for injecting machine checks for testing purposes.
962 If you don't know what a machine check is and you don't do kernel
963 QA it is safe to say n.
965 config X86_THERMAL_VECTOR
967 depends on X86_MCE_INTEL
970 bool "Enable VM86 support" if EXPERT
974 This option is required by programs like DOSEMU to run
975 16-bit real mode legacy code on x86 processors. It also may
976 be needed by software like XFree86 to initialize some video
977 cards via BIOS. Disabling this option saves about 6K.
980 bool "Enable support for 16-bit segments" if EXPERT
983 This option is required by programs like Wine to run 16-bit
984 protected mode legacy code on x86 processors. Disabling
985 this option saves about 300 bytes on i386, or around 6K text
986 plus 16K runtime memory on x86-64,
990 depends on X86_16BIT && X86_32
994 depends on X86_16BIT && X86_64
996 config X86_VSYSCALL_EMULATION
997 bool "Enable vsyscall emulation" if EXPERT
1001 This enables emulation of the legacy vsyscall page. Disabling
1002 it is roughly equivalent to booting with vsyscall=none, except
1003 that it will also disable the helpful warning if a program
1004 tries to use a vsyscall. With this option set to N, offending
1005 programs will just segfault, citing addresses of the form
1008 This option is required by many programs built before 2013, and
1009 care should be used even with newer programs if set to N.
1011 Disabling this option saves about 7K of kernel size and
1012 possibly 4K of additional runtime pagetable memory.
1015 tristate "Toshiba Laptop support"
1018 This adds a driver to safely access the System Management Mode of
1019 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1020 not work on models with a Phoenix BIOS. The System Management Mode
1021 is used to set the BIOS and power saving options on Toshiba portables.
1023 For information on utilities to make use of this driver see the
1024 Toshiba Linux utilities web site at:
1025 <http://www.buzzard.org.uk/toshiba/>.
1027 Say Y if you intend to run this kernel on a Toshiba portable.
1031 tristate "Dell laptop support"
1034 This adds a driver to safely access the System Management Mode
1035 of the CPU on the Dell Inspiron 8000. The System Management Mode
1036 is used to read cpu temperature and cooling fan status and to
1037 control the fans on the I8K portables.
1039 This driver has been tested only on the Inspiron 8000 but it may
1040 also work with other Dell laptops. You can force loading on other
1041 models by passing the parameter `force=1' to the module. Use at
1044 For information on utilities to make use of this driver see the
1045 I8K Linux utilities web site at:
1046 <http://people.debian.org/~dz/i8k/>
1048 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
1051 config X86_REBOOTFIXUPS
1052 bool "Enable X86 board specific fixups for reboot"
1055 This enables chipset and/or board specific fixups to be done
1056 in order to get reboot to work correctly. This is only needed on
1057 some combinations of hardware and BIOS. The symptom, for which
1058 this config is intended, is when reboot ends with a stalled/hung
1061 Currently, the only fixup is for the Geode machines using
1062 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1064 Say Y if you want to enable the fixup. Currently, it's safe to
1065 enable this option even if you don't need it.
1069 tristate "CPU microcode loading support"
1070 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1074 If you say Y here, you will be able to update the microcode on
1075 certain Intel and AMD processors. The Intel support is for the
1076 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1077 Xeon etc. The AMD support is for families 0x10 and later. You will
1078 obviously need the actual microcode binary data itself which is not
1079 shipped with the Linux kernel.
1081 This option selects the general module only, you need to select
1082 at least one vendor specific module as well.
1084 To compile this driver as a module, choose M here: the module
1085 will be called microcode.
1087 config MICROCODE_INTEL
1088 bool "Intel microcode loading support"
1089 depends on MICROCODE
1093 This options enables microcode patch loading support for Intel
1096 For the current Intel microcode data package go to
1097 <https://downloadcenter.intel.com> and search for
1098 'Linux Processor Microcode Data File'.
1100 config MICROCODE_AMD
1101 bool "AMD microcode loading support"
1102 depends on MICROCODE
1105 If you select this option, microcode patch loading support for AMD
1106 processors will be enabled.
1108 config MICROCODE_OLD_INTERFACE
1110 depends on MICROCODE
1112 config MICROCODE_INTEL_EARLY
1115 config MICROCODE_AMD_EARLY
1118 config MICROCODE_EARLY
1119 bool "Early load microcode"
1120 depends on MICROCODE=y && BLK_DEV_INITRD
1121 select MICROCODE_INTEL_EARLY if MICROCODE_INTEL
1122 select MICROCODE_AMD_EARLY if MICROCODE_AMD
1125 This option provides functionality to read additional microcode data
1126 at the beginning of initrd image. The data tells kernel to load
1127 microcode to CPU's as early as possible. No functional change if no
1128 microcode data is glued to the initrd, therefore it's safe to say Y.
1131 tristate "/dev/cpu/*/msr - Model-specific register support"
1133 This device gives privileged processes access to the x86
1134 Model-Specific Registers (MSRs). It is a character device with
1135 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1136 MSR accesses are directed to a specific CPU on multi-processor
1140 tristate "/dev/cpu/*/cpuid - CPU information support"
1142 This device gives processes access to the x86 CPUID instruction to
1143 be executed on a specific processor. It is a character device
1144 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1148 prompt "High Memory Support"
1155 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1156 However, the address space of 32-bit x86 processors is only 4
1157 Gigabytes large. That means that, if you have a large amount of
1158 physical memory, not all of it can be "permanently mapped" by the
1159 kernel. The physical memory that's not permanently mapped is called
1162 If you are compiling a kernel which will never run on a machine with
1163 more than 1 Gigabyte total physical RAM, answer "off" here (default
1164 choice and suitable for most users). This will result in a "3GB/1GB"
1165 split: 3GB are mapped so that each process sees a 3GB virtual memory
1166 space and the remaining part of the 4GB virtual memory space is used
1167 by the kernel to permanently map as much physical memory as
1170 If the machine has between 1 and 4 Gigabytes physical RAM, then
1173 If more than 4 Gigabytes is used then answer "64GB" here. This
1174 selection turns Intel PAE (Physical Address Extension) mode on.
1175 PAE implements 3-level paging on IA32 processors. PAE is fully
1176 supported by Linux, PAE mode is implemented on all recent Intel
1177 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1178 then the kernel will not boot on CPUs that don't support PAE!
1180 The actual amount of total physical memory will either be
1181 auto detected or can be forced by using a kernel command line option
1182 such as "mem=256M". (Try "man bootparam" or see the documentation of
1183 your boot loader (lilo or loadlin) about how to pass options to the
1184 kernel at boot time.)
1186 If unsure, say "off".
1191 Select this if you have a 32-bit processor and between 1 and 4
1192 gigabytes of physical RAM.
1199 Select this if you have a 32-bit processor and more than 4
1200 gigabytes of physical RAM.
1205 prompt "Memory split" if EXPERT
1209 Select the desired split between kernel and user memory.
1211 If the address range available to the kernel is less than the
1212 physical memory installed, the remaining memory will be available
1213 as "high memory". Accessing high memory is a little more costly
1214 than low memory, as it needs to be mapped into the kernel first.
1215 Note that increasing the kernel address space limits the range
1216 available to user programs, making the address space there
1217 tighter. Selecting anything other than the default 3G/1G split
1218 will also likely make your kernel incompatible with binary-only
1221 If you are not absolutely sure what you are doing, leave this
1225 bool "3G/1G user/kernel split"
1226 config VMSPLIT_3G_OPT
1228 bool "3G/1G user/kernel split (for full 1G low memory)"
1230 bool "2G/2G user/kernel split"
1231 config VMSPLIT_2G_OPT
1233 bool "2G/2G user/kernel split (for full 2G low memory)"
1235 bool "1G/3G user/kernel split"
1240 default 0xB0000000 if VMSPLIT_3G_OPT
1241 default 0x80000000 if VMSPLIT_2G
1242 default 0x78000000 if VMSPLIT_2G_OPT
1243 default 0x40000000 if VMSPLIT_1G
1249 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1252 bool "PAE (Physical Address Extension) Support"
1253 depends on X86_32 && !HIGHMEM4G
1255 PAE is required for NX support, and furthermore enables
1256 larger swapspace support for non-overcommit purposes. It
1257 has the cost of more pagetable lookup overhead, and also
1258 consumes more pagetable space per process.
1260 config ARCH_PHYS_ADDR_T_64BIT
1262 depends on X86_64 || X86_PAE
1264 config ARCH_DMA_ADDR_T_64BIT
1266 depends on X86_64 || HIGHMEM64G
1268 config DIRECT_GBPAGES
1269 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1273 Allow the kernel linear mapping to use 1GB pages on CPUs that
1274 support it. This can improve the kernel's performance a tiny bit by
1275 reducing TLB pressure. If in doubt, say "Y".
1277 # Common NUMA Features
1279 bool "Numa Memory Allocation and Scheduler Support"
1281 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1282 default y if X86_BIGSMP
1284 Enable NUMA (Non Uniform Memory Access) support.
1286 The kernel will try to allocate memory used by a CPU on the
1287 local memory controller of the CPU and add some more
1288 NUMA awareness to the kernel.
1290 For 64-bit this is recommended if the system is Intel Core i7
1291 (or later), AMD Opteron, or EM64T NUMA.
1293 For 32-bit this is only needed if you boot a 32-bit
1294 kernel on a 64-bit NUMA platform.
1296 Otherwise, you should say N.
1300 prompt "Old style AMD Opteron NUMA detection"
1301 depends on X86_64 && NUMA && PCI
1303 Enable AMD NUMA node topology detection. You should say Y here if
1304 you have a multi processor AMD system. This uses an old method to
1305 read the NUMA configuration directly from the builtin Northbridge
1306 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1307 which also takes priority if both are compiled in.
1309 config X86_64_ACPI_NUMA
1311 prompt "ACPI NUMA detection"
1312 depends on X86_64 && NUMA && ACPI && PCI
1315 Enable ACPI SRAT based node topology detection.
1317 # Some NUMA nodes have memory ranges that span
1318 # other nodes. Even though a pfn is valid and
1319 # between a node's start and end pfns, it may not
1320 # reside on that node. See memmap_init_zone()
1322 config NODES_SPAN_OTHER_NODES
1324 depends on X86_64_ACPI_NUMA
1327 bool "NUMA emulation"
1330 Enable NUMA emulation. A flat machine will be split
1331 into virtual nodes when booted with "numa=fake=N", where N is the
1332 number of nodes. This is only useful for debugging.
1335 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1337 default "10" if MAXSMP
1338 default "6" if X86_64
1340 depends on NEED_MULTIPLE_NODES
1342 Specify the maximum number of NUMA Nodes available on the target
1343 system. Increases memory reserved to accommodate various tables.
1345 config ARCH_HAVE_MEMORY_PRESENT
1347 depends on X86_32 && DISCONTIGMEM
1349 config NEED_NODE_MEMMAP_SIZE
1351 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1353 config ARCH_FLATMEM_ENABLE
1355 depends on X86_32 && !NUMA
1357 config ARCH_DISCONTIGMEM_ENABLE
1359 depends on NUMA && X86_32
1361 config ARCH_DISCONTIGMEM_DEFAULT
1363 depends on NUMA && X86_32
1365 config ARCH_SPARSEMEM_ENABLE
1367 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1368 select SPARSEMEM_STATIC if X86_32
1369 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1371 config ARCH_SPARSEMEM_DEFAULT
1375 config ARCH_SELECT_MEMORY_MODEL
1377 depends on ARCH_SPARSEMEM_ENABLE
1379 config ARCH_MEMORY_PROBE
1380 bool "Enable sysfs memory/probe interface"
1381 depends on X86_64 && MEMORY_HOTPLUG
1383 This option enables a sysfs memory/probe interface for testing.
1384 See Documentation/memory-hotplug.txt for more information.
1385 If you are unsure how to answer this question, answer N.
1387 config ARCH_PROC_KCORE_TEXT
1389 depends on X86_64 && PROC_KCORE
1391 config ILLEGAL_POINTER_VALUE
1394 default 0xdead000000000000 if X86_64
1399 bool "Allocate 3rd-level pagetables from highmem"
1402 The VM uses one page table entry for each page of physical memory.
1403 For systems with a lot of RAM, this can be wasteful of precious
1404 low memory. Setting this option will put user-space page table
1405 entries in high memory.
1407 config X86_CHECK_BIOS_CORRUPTION
1408 bool "Check for low memory corruption"
1410 Periodically check for memory corruption in low memory, which
1411 is suspected to be caused by BIOS. Even when enabled in the
1412 configuration, it is disabled at runtime. Enable it by
1413 setting "memory_corruption_check=1" on the kernel command
1414 line. By default it scans the low 64k of memory every 60
1415 seconds; see the memory_corruption_check_size and
1416 memory_corruption_check_period parameters in
1417 Documentation/kernel-parameters.txt to adjust this.
1419 When enabled with the default parameters, this option has
1420 almost no overhead, as it reserves a relatively small amount
1421 of memory and scans it infrequently. It both detects corruption
1422 and prevents it from affecting the running system.
1424 It is, however, intended as a diagnostic tool; if repeatable
1425 BIOS-originated corruption always affects the same memory,
1426 you can use memmap= to prevent the kernel from using that
1429 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1430 bool "Set the default setting of memory_corruption_check"
1431 depends on X86_CHECK_BIOS_CORRUPTION
1434 Set whether the default state of memory_corruption_check is
1437 config X86_RESERVE_LOW
1438 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1442 Specify the amount of low memory to reserve for the BIOS.
1444 The first page contains BIOS data structures that the kernel
1445 must not use, so that page must always be reserved.
1447 By default we reserve the first 64K of physical RAM, as a
1448 number of BIOSes are known to corrupt that memory range
1449 during events such as suspend/resume or monitor cable
1450 insertion, so it must not be used by the kernel.
1452 You can set this to 4 if you are absolutely sure that you
1453 trust the BIOS to get all its memory reservations and usages
1454 right. If you know your BIOS have problems beyond the
1455 default 64K area, you can set this to 640 to avoid using the
1456 entire low memory range.
1458 If you have doubts about the BIOS (e.g. suspend/resume does
1459 not work or there's kernel crashes after certain hardware
1460 hotplug events) then you might want to enable
1461 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1462 typical corruption patterns.
1464 Leave this to the default value of 64 if you are unsure.
1466 config MATH_EMULATION
1468 prompt "Math emulation" if X86_32
1470 Linux can emulate a math coprocessor (used for floating point
1471 operations) if you don't have one. 486DX and Pentium processors have
1472 a math coprocessor built in, 486SX and 386 do not, unless you added
1473 a 487DX or 387, respectively. (The messages during boot time can
1474 give you some hints here ["man dmesg"].) Everyone needs either a
1475 coprocessor or this emulation.
1477 If you don't have a math coprocessor, you need to say Y here; if you
1478 say Y here even though you have a coprocessor, the coprocessor will
1479 be used nevertheless. (This behavior can be changed with the kernel
1480 command line option "no387", which comes handy if your coprocessor
1481 is broken. Try "man bootparam" or see the documentation of your boot
1482 loader (lilo or loadlin) about how to pass options to the kernel at
1483 boot time.) This means that it is a good idea to say Y here if you
1484 intend to use this kernel on different machines.
1486 More information about the internals of the Linux math coprocessor
1487 emulation can be found in <file:arch/x86/math-emu/README>.
1489 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1490 kernel, it won't hurt.
1494 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1496 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1497 the Memory Type Range Registers (MTRRs) may be used to control
1498 processor access to memory ranges. This is most useful if you have
1499 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1500 allows bus write transfers to be combined into a larger transfer
1501 before bursting over the PCI/AGP bus. This can increase performance
1502 of image write operations 2.5 times or more. Saying Y here creates a
1503 /proc/mtrr file which may be used to manipulate your processor's
1504 MTRRs. Typically the X server should use this.
1506 This code has a reasonably generic interface so that similar
1507 control registers on other processors can be easily supported
1510 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1511 Registers (ARRs) which provide a similar functionality to MTRRs. For
1512 these, the ARRs are used to emulate the MTRRs.
1513 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1514 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1515 write-combining. All of these processors are supported by this code
1516 and it makes sense to say Y here if you have one of them.
1518 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1519 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1520 can lead to all sorts of problems, so it's good to say Y here.
1522 You can safely say Y even if your machine doesn't have MTRRs, you'll
1523 just add about 9 KB to your kernel.
1525 See <file:Documentation/x86/mtrr.txt> for more information.
1527 config MTRR_SANITIZER
1529 prompt "MTRR cleanup support"
1532 Convert MTRR layout from continuous to discrete, so X drivers can
1533 add writeback entries.
1535 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1536 The largest mtrr entry size for a continuous block can be set with
1541 config MTRR_SANITIZER_ENABLE_DEFAULT
1542 int "MTRR cleanup enable value (0-1)"
1545 depends on MTRR_SANITIZER
1547 Enable mtrr cleanup default value
1549 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1550 int "MTRR cleanup spare reg num (0-7)"
1553 depends on MTRR_SANITIZER
1555 mtrr cleanup spare entries default, it can be changed via
1556 mtrr_spare_reg_nr=N on the kernel command line.
1560 prompt "x86 PAT support" if EXPERT
1563 Use PAT attributes to setup page level cache control.
1565 PATs are the modern equivalents of MTRRs and are much more
1566 flexible than MTRRs.
1568 Say N here if you see bootup problems (boot crash, boot hang,
1569 spontaneous reboots) or a non-working video driver.
1573 config ARCH_USES_PG_UNCACHED
1579 prompt "x86 architectural random number generator" if EXPERT
1581 Enable the x86 architectural RDRAND instruction
1582 (Intel Bull Mountain technology) to generate random numbers.
1583 If supported, this is a high bandwidth, cryptographically
1584 secure hardware random number generator.
1588 prompt "Supervisor Mode Access Prevention" if EXPERT
1590 Supervisor Mode Access Prevention (SMAP) is a security
1591 feature in newer Intel processors. There is a small
1592 performance cost if this enabled and turned on; there is
1593 also a small increase in the kernel size if this is enabled.
1598 bool "EFI runtime service support"
1601 select EFI_RUNTIME_WRAPPERS
1603 This enables the kernel to use EFI runtime services that are
1604 available (such as the EFI variable services).
1606 This option is only useful on systems that have EFI firmware.
1607 In addition, you should use the latest ELILO loader available
1608 at <http://elilo.sourceforge.net> in order to take advantage
1609 of EFI runtime services. However, even with this option, the
1610 resultant kernel should continue to boot on existing non-EFI
1614 bool "EFI stub support"
1615 depends on EFI && !X86_USE_3DNOW
1618 This kernel feature allows a bzImage to be loaded directly
1619 by EFI firmware without the use of a bootloader.
1621 See Documentation/efi-stub.txt for more information.
1624 bool "EFI mixed-mode support"
1625 depends on EFI_STUB && X86_64
1627 Enabling this feature allows a 64-bit kernel to be booted
1628 on a 32-bit firmware, provided that your CPU supports 64-bit
1631 Note that it is not possible to boot a mixed-mode enabled
1632 kernel via the EFI boot stub - a bootloader that supports
1633 the EFI handover protocol must be used.
1639 prompt "Enable seccomp to safely compute untrusted bytecode"
1641 This kernel feature is useful for number crunching applications
1642 that may need to compute untrusted bytecode during their
1643 execution. By using pipes or other transports made available to
1644 the process as file descriptors supporting the read/write
1645 syscalls, it's possible to isolate those applications in
1646 their own address space using seccomp. Once seccomp is
1647 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1648 and the task is only allowed to execute a few safe syscalls
1649 defined by each seccomp mode.
1651 If unsure, say Y. Only embedded should say N here.
1653 source kernel/Kconfig.hz
1656 bool "kexec system call"
1658 kexec is a system call that implements the ability to shutdown your
1659 current kernel, and to start another kernel. It is like a reboot
1660 but it is independent of the system firmware. And like a reboot
1661 you can start any kernel with it, not just Linux.
1663 The name comes from the similarity to the exec system call.
1665 It is an ongoing process to be certain the hardware in a machine
1666 is properly shutdown, so do not be surprised if this code does not
1667 initially work for you. As of this writing the exact hardware
1668 interface is strongly in flux, so no good recommendation can be
1672 bool "kexec file based system call"
1677 depends on CRYPTO_SHA256=y
1679 This is new version of kexec system call. This system call is
1680 file based and takes file descriptors as system call argument
1681 for kernel and initramfs as opposed to list of segments as
1682 accepted by previous system call.
1684 config KEXEC_VERIFY_SIG
1685 bool "Verify kernel signature during kexec_file_load() syscall"
1686 depends on KEXEC_FILE
1688 This option makes kernel signature verification mandatory for
1689 kexec_file_load() syscall. If kernel is signature can not be
1690 verified, kexec_file_load() will fail.
1692 This option enforces signature verification at generic level.
1693 One needs to enable signature verification for type of kernel
1694 image being loaded to make sure it works. For example, enable
1695 bzImage signature verification option to be able to load and
1696 verify signatures of bzImage. Otherwise kernel loading will fail.
1698 config KEXEC_BZIMAGE_VERIFY_SIG
1699 bool "Enable bzImage signature verification support"
1700 depends on KEXEC_VERIFY_SIG
1701 depends on SIGNED_PE_FILE_VERIFICATION
1702 select SYSTEM_TRUSTED_KEYRING
1704 Enable bzImage signature verification support.
1707 bool "kernel crash dumps"
1708 depends on X86_64 || (X86_32 && HIGHMEM)
1710 Generate crash dump after being started by kexec.
1711 This should be normally only set in special crash dump kernels
1712 which are loaded in the main kernel with kexec-tools into
1713 a specially reserved region and then later executed after
1714 a crash by kdump/kexec. The crash dump kernel must be compiled
1715 to a memory address not used by the main kernel or BIOS using
1716 PHYSICAL_START, or it must be built as a relocatable image
1717 (CONFIG_RELOCATABLE=y).
1718 For more details see Documentation/kdump/kdump.txt
1722 depends on KEXEC && HIBERNATION
1724 Jump between original kernel and kexeced kernel and invoke
1725 code in physical address mode via KEXEC
1727 config PHYSICAL_START
1728 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1731 This gives the physical address where the kernel is loaded.
1733 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1734 bzImage will decompress itself to above physical address and
1735 run from there. Otherwise, bzImage will run from the address where
1736 it has been loaded by the boot loader and will ignore above physical
1739 In normal kdump cases one does not have to set/change this option
1740 as now bzImage can be compiled as a completely relocatable image
1741 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1742 address. This option is mainly useful for the folks who don't want
1743 to use a bzImage for capturing the crash dump and want to use a
1744 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1745 to be specifically compiled to run from a specific memory area
1746 (normally a reserved region) and this option comes handy.
1748 So if you are using bzImage for capturing the crash dump,
1749 leave the value here unchanged to 0x1000000 and set
1750 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1751 for capturing the crash dump change this value to start of
1752 the reserved region. In other words, it can be set based on
1753 the "X" value as specified in the "crashkernel=YM@XM"
1754 command line boot parameter passed to the panic-ed
1755 kernel. Please take a look at Documentation/kdump/kdump.txt
1756 for more details about crash dumps.
1758 Usage of bzImage for capturing the crash dump is recommended as
1759 one does not have to build two kernels. Same kernel can be used
1760 as production kernel and capture kernel. Above option should have
1761 gone away after relocatable bzImage support is introduced. But it
1762 is present because there are users out there who continue to use
1763 vmlinux for dump capture. This option should go away down the
1766 Don't change this unless you know what you are doing.
1769 bool "Build a relocatable kernel"
1772 This builds a kernel image that retains relocation information
1773 so it can be loaded someplace besides the default 1MB.
1774 The relocations tend to make the kernel binary about 10% larger,
1775 but are discarded at runtime.
1777 One use is for the kexec on panic case where the recovery kernel
1778 must live at a different physical address than the primary
1781 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1782 it has been loaded at and the compile time physical address
1783 (CONFIG_PHYSICAL_START) is used as the minimum location.
1785 config RANDOMIZE_BASE
1786 bool "Randomize the address of the kernel image"
1787 depends on RELOCATABLE
1790 Randomizes the physical and virtual address at which the
1791 kernel image is decompressed, as a security feature that
1792 deters exploit attempts relying on knowledge of the location
1793 of kernel internals.
1795 Entropy is generated using the RDRAND instruction if it is
1796 supported. If RDTSC is supported, it is used as well. If
1797 neither RDRAND nor RDTSC are supported, then randomness is
1798 read from the i8254 timer.
1800 The kernel will be offset by up to RANDOMIZE_BASE_MAX_OFFSET,
1801 and aligned according to PHYSICAL_ALIGN. Since the kernel is
1802 built using 2GiB addressing, and PHYSICAL_ALGIN must be at a
1803 minimum of 2MiB, only 10 bits of entropy is theoretically
1804 possible. At best, due to page table layouts, 64-bit can use
1805 9 bits of entropy and 32-bit uses 8 bits.
1809 config RANDOMIZE_BASE_MAX_OFFSET
1810 hex "Maximum kASLR offset allowed" if EXPERT
1811 depends on RANDOMIZE_BASE
1812 range 0x0 0x20000000 if X86_32
1813 default "0x20000000" if X86_32
1814 range 0x0 0x40000000 if X86_64
1815 default "0x40000000" if X86_64
1817 The lesser of RANDOMIZE_BASE_MAX_OFFSET and available physical
1818 memory is used to determine the maximal offset in bytes that will
1819 be applied to the kernel when kernel Address Space Layout
1820 Randomization (kASLR) is active. This must be a multiple of
1823 On 32-bit this is limited to 512MiB by page table layouts. The
1826 On 64-bit this is limited by how the kernel fixmap page table is
1827 positioned, so this cannot be larger than 1GiB currently. Without
1828 RANDOMIZE_BASE, there is a 512MiB to 1.5GiB split between kernel
1829 and modules. When RANDOMIZE_BASE_MAX_OFFSET is above 512MiB, the
1830 modules area will shrink to compensate, up to the current maximum
1831 1GiB to 1GiB split. The default is 1GiB.
1833 If unsure, leave at the default value.
1835 # Relocation on x86 needs some additional build support
1836 config X86_NEED_RELOCS
1838 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
1840 config PHYSICAL_ALIGN
1841 hex "Alignment value to which kernel should be aligned"
1843 range 0x2000 0x1000000 if X86_32
1844 range 0x200000 0x1000000 if X86_64
1846 This value puts the alignment restrictions on physical address
1847 where kernel is loaded and run from. Kernel is compiled for an
1848 address which meets above alignment restriction.
1850 If bootloader loads the kernel at a non-aligned address and
1851 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1852 address aligned to above value and run from there.
1854 If bootloader loads the kernel at a non-aligned address and
1855 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1856 load address and decompress itself to the address it has been
1857 compiled for and run from there. The address for which kernel is
1858 compiled already meets above alignment restrictions. Hence the
1859 end result is that kernel runs from a physical address meeting
1860 above alignment restrictions.
1862 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1863 this value must be a multiple of 0x200000.
1865 Don't change this unless you know what you are doing.
1868 bool "Support for hot-pluggable CPUs"
1871 Say Y here to allow turning CPUs off and on. CPUs can be
1872 controlled through /sys/devices/system/cpu.
1873 ( Note: power management support will enable this option
1874 automatically on SMP systems. )
1875 Say N if you want to disable CPU hotplug.
1877 config BOOTPARAM_HOTPLUG_CPU0
1878 bool "Set default setting of cpu0_hotpluggable"
1880 depends on HOTPLUG_CPU
1882 Set whether default state of cpu0_hotpluggable is on or off.
1884 Say Y here to enable CPU0 hotplug by default. If this switch
1885 is turned on, there is no need to give cpu0_hotplug kernel
1886 parameter and the CPU0 hotplug feature is enabled by default.
1888 Please note: there are two known CPU0 dependencies if you want
1889 to enable the CPU0 hotplug feature either by this switch or by
1890 cpu0_hotplug kernel parameter.
1892 First, resume from hibernate or suspend always starts from CPU0.
1893 So hibernate and suspend are prevented if CPU0 is offline.
1895 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1896 offline if any interrupt can not migrate out of CPU0. There may
1897 be other CPU0 dependencies.
1899 Please make sure the dependencies are under your control before
1900 you enable this feature.
1902 Say N if you don't want to enable CPU0 hotplug feature by default.
1903 You still can enable the CPU0 hotplug feature at boot by kernel
1904 parameter cpu0_hotplug.
1906 config DEBUG_HOTPLUG_CPU0
1908 prompt "Debug CPU0 hotplug"
1909 depends on HOTPLUG_CPU
1911 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1912 soon as possible and boots up userspace with CPU0 offlined. User
1913 can online CPU0 back after boot time.
1915 To debug CPU0 hotplug, you need to enable CPU0 offline/online
1916 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1917 compilation or giving cpu0_hotplug kernel parameter at boot.
1923 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
1924 depends on X86_32 || IA32_EMULATION
1926 Certain buggy versions of glibc will crash if they are
1927 presented with a 32-bit vDSO that is not mapped at the address
1928 indicated in its segment table.
1930 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
1931 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
1932 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
1933 the only released version with the bug, but OpenSUSE 9
1934 contains a buggy "glibc 2.3.2".
1936 The symptom of the bug is that everything crashes on startup, saying:
1937 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
1939 Saying Y here changes the default value of the vdso32 boot
1940 option from 1 to 0, which turns off the 32-bit vDSO entirely.
1941 This works around the glibc bug but hurts performance.
1943 If unsure, say N: if you are compiling your own kernel, you
1944 are unlikely to be using a buggy version of glibc.
1947 bool "Built-in kernel command line"
1949 Allow for specifying boot arguments to the kernel at
1950 build time. On some systems (e.g. embedded ones), it is
1951 necessary or convenient to provide some or all of the
1952 kernel boot arguments with the kernel itself (that is,
1953 to not rely on the boot loader to provide them.)
1955 To compile command line arguments into the kernel,
1956 set this option to 'Y', then fill in the
1957 the boot arguments in CONFIG_CMDLINE.
1959 Systems with fully functional boot loaders (i.e. non-embedded)
1960 should leave this option set to 'N'.
1963 string "Built-in kernel command string"
1964 depends on CMDLINE_BOOL
1967 Enter arguments here that should be compiled into the kernel
1968 image and used at boot time. If the boot loader provides a
1969 command line at boot time, it is appended to this string to
1970 form the full kernel command line, when the system boots.
1972 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1973 change this behavior.
1975 In most cases, the command line (whether built-in or provided
1976 by the boot loader) should specify the device for the root
1979 config CMDLINE_OVERRIDE
1980 bool "Built-in command line overrides boot loader arguments"
1981 depends on CMDLINE_BOOL
1983 Set this option to 'Y' to have the kernel ignore the boot loader
1984 command line, and use ONLY the built-in command line.
1986 This is used to work around broken boot loaders. This should
1987 be set to 'N' under normal conditions.
1991 config ARCH_ENABLE_MEMORY_HOTPLUG
1993 depends on X86_64 || (X86_32 && HIGHMEM)
1995 config ARCH_ENABLE_MEMORY_HOTREMOVE
1997 depends on MEMORY_HOTPLUG
1999 config USE_PERCPU_NUMA_NODE_ID
2003 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2005 depends on X86_64 || X86_PAE
2007 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2009 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2011 menu "Power management and ACPI options"
2013 config ARCH_HIBERNATION_HEADER
2015 depends on X86_64 && HIBERNATION
2017 source "kernel/power/Kconfig"
2019 source "drivers/acpi/Kconfig"
2021 source "drivers/sfi/Kconfig"
2028 tristate "APM (Advanced Power Management) BIOS support"
2029 depends on X86_32 && PM_SLEEP
2031 APM is a BIOS specification for saving power using several different
2032 techniques. This is mostly useful for battery powered laptops with
2033 APM compliant BIOSes. If you say Y here, the system time will be
2034 reset after a RESUME operation, the /proc/apm device will provide
2035 battery status information, and user-space programs will receive
2036 notification of APM "events" (e.g. battery status change).
2038 If you select "Y" here, you can disable actual use of the APM
2039 BIOS by passing the "apm=off" option to the kernel at boot time.
2041 Note that the APM support is almost completely disabled for
2042 machines with more than one CPU.
2044 In order to use APM, you will need supporting software. For location
2045 and more information, read <file:Documentation/power/apm-acpi.txt>
2046 and the Battery Powered Linux mini-HOWTO, available from
2047 <http://www.tldp.org/docs.html#howto>.
2049 This driver does not spin down disk drives (see the hdparm(8)
2050 manpage ("man 8 hdparm") for that), and it doesn't turn off
2051 VESA-compliant "green" monitors.
2053 This driver does not support the TI 4000M TravelMate and the ACER
2054 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2055 desktop machines also don't have compliant BIOSes, and this driver
2056 may cause those machines to panic during the boot phase.
2058 Generally, if you don't have a battery in your machine, there isn't
2059 much point in using this driver and you should say N. If you get
2060 random kernel OOPSes or reboots that don't seem to be related to
2061 anything, try disabling/enabling this option (or disabling/enabling
2064 Some other things you should try when experiencing seemingly random,
2067 1) make sure that you have enough swap space and that it is
2069 2) pass the "no-hlt" option to the kernel
2070 3) switch on floating point emulation in the kernel and pass
2071 the "no387" option to the kernel
2072 4) pass the "floppy=nodma" option to the kernel
2073 5) pass the "mem=4M" option to the kernel (thereby disabling
2074 all but the first 4 MB of RAM)
2075 6) make sure that the CPU is not over clocked.
2076 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2077 8) disable the cache from your BIOS settings
2078 9) install a fan for the video card or exchange video RAM
2079 10) install a better fan for the CPU
2080 11) exchange RAM chips
2081 12) exchange the motherboard.
2083 To compile this driver as a module, choose M here: the
2084 module will be called apm.
2088 config APM_IGNORE_USER_SUSPEND
2089 bool "Ignore USER SUSPEND"
2091 This option will ignore USER SUSPEND requests. On machines with a
2092 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2093 series notebooks, it is necessary to say Y because of a BIOS bug.
2095 config APM_DO_ENABLE
2096 bool "Enable PM at boot time"
2098 Enable APM features at boot time. From page 36 of the APM BIOS
2099 specification: "When disabled, the APM BIOS does not automatically
2100 power manage devices, enter the Standby State, enter the Suspend
2101 State, or take power saving steps in response to CPU Idle calls."
2102 This driver will make CPU Idle calls when Linux is idle (unless this
2103 feature is turned off -- see "Do CPU IDLE calls", below). This
2104 should always save battery power, but more complicated APM features
2105 will be dependent on your BIOS implementation. You may need to turn
2106 this option off if your computer hangs at boot time when using APM
2107 support, or if it beeps continuously instead of suspending. Turn
2108 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2109 T400CDT. This is off by default since most machines do fine without
2114 bool "Make CPU Idle calls when idle"
2116 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2117 On some machines, this can activate improved power savings, such as
2118 a slowed CPU clock rate, when the machine is idle. These idle calls
2119 are made after the idle loop has run for some length of time (e.g.,
2120 333 mS). On some machines, this will cause a hang at boot time or
2121 whenever the CPU becomes idle. (On machines with more than one CPU,
2122 this option does nothing.)
2124 config APM_DISPLAY_BLANK
2125 bool "Enable console blanking using APM"
2127 Enable console blanking using the APM. Some laptops can use this to
2128 turn off the LCD backlight when the screen blanker of the Linux
2129 virtual console blanks the screen. Note that this is only used by
2130 the virtual console screen blanker, and won't turn off the backlight
2131 when using the X Window system. This also doesn't have anything to
2132 do with your VESA-compliant power-saving monitor. Further, this
2133 option doesn't work for all laptops -- it might not turn off your
2134 backlight at all, or it might print a lot of errors to the console,
2135 especially if you are using gpm.
2137 config APM_ALLOW_INTS
2138 bool "Allow interrupts during APM BIOS calls"
2140 Normally we disable external interrupts while we are making calls to
2141 the APM BIOS as a measure to lessen the effects of a badly behaving
2142 BIOS implementation. The BIOS should reenable interrupts if it
2143 needs to. Unfortunately, some BIOSes do not -- especially those in
2144 many of the newer IBM Thinkpads. If you experience hangs when you
2145 suspend, try setting this to Y. Otherwise, say N.
2149 source "drivers/cpufreq/Kconfig"
2151 source "drivers/cpuidle/Kconfig"
2153 source "drivers/idle/Kconfig"
2158 menu "Bus options (PCI etc.)"
2164 Find out whether you have a PCI motherboard. PCI is the name of a
2165 bus system, i.e. the way the CPU talks to the other stuff inside
2166 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2167 VESA. If you have PCI, say Y, otherwise N.
2170 prompt "PCI access mode"
2171 depends on X86_32 && PCI
2174 On PCI systems, the BIOS can be used to detect the PCI devices and
2175 determine their configuration. However, some old PCI motherboards
2176 have BIOS bugs and may crash if this is done. Also, some embedded
2177 PCI-based systems don't have any BIOS at all. Linux can also try to
2178 detect the PCI hardware directly without using the BIOS.
2180 With this option, you can specify how Linux should detect the
2181 PCI devices. If you choose "BIOS", the BIOS will be used,
2182 if you choose "Direct", the BIOS won't be used, and if you
2183 choose "MMConfig", then PCI Express MMCONFIG will be used.
2184 If you choose "Any", the kernel will try MMCONFIG, then the
2185 direct access method and falls back to the BIOS if that doesn't
2186 work. If unsure, go with the default, which is "Any".
2191 config PCI_GOMMCONFIG
2208 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2210 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2213 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2217 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2221 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2225 depends on PCI && XEN
2233 bool "Support mmconfig PCI config space access"
2234 depends on X86_64 && PCI && ACPI
2236 config PCI_CNB20LE_QUIRK
2237 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2240 Read the PCI windows out of the CNB20LE host bridge. This allows
2241 PCI hotplug to work on systems with the CNB20LE chipset which do
2244 There's no public spec for this chipset, and this functionality
2245 is known to be incomplete.
2247 You should say N unless you know you need this.
2249 source "drivers/pci/pcie/Kconfig"
2251 source "drivers/pci/Kconfig"
2253 # x86_64 have no ISA slots, but can have ISA-style DMA.
2255 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2258 Enables ISA-style DMA support for devices requiring such controllers.
2266 Find out whether you have ISA slots on your motherboard. ISA is the
2267 name of a bus system, i.e. the way the CPU talks to the other stuff
2268 inside your box. Other bus systems are PCI, EISA, MicroChannel
2269 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2270 newer boards don't support it. If you have ISA, say Y, otherwise N.
2276 The Extended Industry Standard Architecture (EISA) bus was
2277 developed as an open alternative to the IBM MicroChannel bus.
2279 The EISA bus provided some of the features of the IBM MicroChannel
2280 bus while maintaining backward compatibility with cards made for
2281 the older ISA bus. The EISA bus saw limited use between 1988 and
2282 1995 when it was made obsolete by the PCI bus.
2284 Say Y here if you are building a kernel for an EISA-based machine.
2288 source "drivers/eisa/Kconfig"
2291 tristate "NatSemi SCx200 support"
2293 This provides basic support for National Semiconductor's
2294 (now AMD's) Geode processors. The driver probes for the
2295 PCI-IDs of several on-chip devices, so its a good dependency
2296 for other scx200_* drivers.
2298 If compiled as a module, the driver is named scx200.
2300 config SCx200HR_TIMER
2301 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2305 This driver provides a clocksource built upon the on-chip
2306 27MHz high-resolution timer. Its also a workaround for
2307 NSC Geode SC-1100's buggy TSC, which loses time when the
2308 processor goes idle (as is done by the scheduler). The
2309 other workaround is idle=poll boot option.
2312 bool "One Laptop Per Child support"
2319 Add support for detecting the unique features of the OLPC
2323 bool "OLPC XO-1 Power Management"
2324 depends on OLPC && MFD_CS5535 && PM_SLEEP
2327 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2330 bool "OLPC XO-1 Real Time Clock"
2331 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2333 Add support for the XO-1 real time clock, which can be used as a
2334 programmable wakeup source.
2337 bool "OLPC XO-1 SCI extras"
2338 depends on OLPC && OLPC_XO1_PM
2344 Add support for SCI-based features of the OLPC XO-1 laptop:
2345 - EC-driven system wakeups
2349 - AC adapter status updates
2350 - Battery status updates
2352 config OLPC_XO15_SCI
2353 bool "OLPC XO-1.5 SCI extras"
2354 depends on OLPC && ACPI
2357 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2358 - EC-driven system wakeups
2359 - AC adapter status updates
2360 - Battery status updates
2363 bool "PCEngines ALIX System Support (LED setup)"
2366 This option enables system support for the PCEngines ALIX.
2367 At present this just sets up LEDs for GPIO control on
2368 ALIX2/3/6 boards. However, other system specific setup should
2371 Note: You must still enable the drivers for GPIO and LED support
2372 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2374 Note: You have to set alix.force=1 for boards with Award BIOS.
2377 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2380 This option enables system support for the Soekris Engineering net5501.
2383 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2387 This option enables system support for the Traverse Technologies GEOS.
2390 bool "Technologic Systems TS-5500 platform support"
2392 select CHECK_SIGNATURE
2396 This option enables system support for the Technologic Systems TS-5500.
2402 depends on CPU_SUP_AMD && PCI
2404 source "drivers/pcmcia/Kconfig"
2406 source "drivers/pci/hotplug/Kconfig"
2409 tristate "RapidIO support"
2413 If enabled this option will include drivers and the core
2414 infrastructure code to support RapidIO interconnect devices.
2416 source "drivers/rapidio/Kconfig"
2419 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2421 Firmwares often provide initial graphics framebuffers so the BIOS,
2422 bootloader or kernel can show basic video-output during boot for
2423 user-guidance and debugging. Historically, x86 used the VESA BIOS
2424 Extensions and EFI-framebuffers for this, which are mostly limited
2426 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2427 framebuffers so the new generic system-framebuffer drivers can be
2428 used on x86. If the framebuffer is not compatible with the generic
2429 modes, it is adverticed as fallback platform framebuffer so legacy
2430 drivers like efifb, vesafb and uvesafb can pick it up.
2431 If this option is not selected, all system framebuffers are always
2432 marked as fallback platform framebuffers as usual.
2434 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2435 not be able to pick up generic system framebuffers if this option
2436 is selected. You are highly encouraged to enable simplefb as
2437 replacement if you select this option. simplefb can correctly deal
2438 with generic system framebuffers. But you should still keep vesafb
2439 and others enabled as fallback if a system framebuffer is
2440 incompatible with simplefb.
2447 menu "Executable file formats / Emulations"
2449 source "fs/Kconfig.binfmt"
2451 config IA32_EMULATION
2452 bool "IA32 Emulation"
2455 select COMPAT_BINFMT_ELF
2458 Include code to run legacy 32-bit programs under a
2459 64-bit kernel. You should likely turn this on, unless you're
2460 100% sure that you don't have any 32-bit programs left.
2463 tristate "IA32 a.out support"
2464 depends on IA32_EMULATION
2466 Support old a.out binaries in the 32bit emulation.
2469 bool "x32 ABI for 64-bit mode"
2470 depends on X86_64 && IA32_EMULATION
2472 Include code to run binaries for the x32 native 32-bit ABI
2473 for 64-bit processors. An x32 process gets access to the
2474 full 64-bit register file and wide data path while leaving
2475 pointers at 32 bits for smaller memory footprint.
2477 You will need a recent binutils (2.22 or later) with
2478 elf32_x86_64 support enabled to compile a kernel with this
2483 depends on IA32_EMULATION || X86_X32
2484 select ARCH_WANT_OLD_COMPAT_IPC
2487 config COMPAT_FOR_U64_ALIGNMENT
2490 config SYSVIPC_COMPAT
2502 config HAVE_ATOMIC_IOMAP
2506 config X86_DEV_DMA_OPS
2508 depends on X86_64 || STA2X11
2510 config X86_DMA_REMAP
2518 source "net/Kconfig"
2520 source "drivers/Kconfig"
2522 source "drivers/firmware/Kconfig"
2526 source "arch/x86/Kconfig.debug"
2528 source "security/Kconfig"
2530 source "crypto/Kconfig"
2532 source "arch/x86/kvm/Kconfig"
2534 source "lib/Kconfig"