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
23 select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
24 select HAVE_AOUT if X86_32
25 select HAVE_UNSTABLE_SCHED_CLOCK
26 select ARCH_SUPPORTS_NUMA_BALANCING
27 select ARCH_WANTS_PROT_NUMA_PROT_NONE
30 select HAVE_PCSPKR_PLATFORM
31 select HAVE_PERF_EVENTS
32 select HAVE_IOREMAP_PROT
35 select HAVE_MEMBLOCK_NODE_MAP
36 select ARCH_DISCARD_MEMBLOCK
37 select ARCH_WANT_OPTIONAL_GPIOLIB
38 select ARCH_WANT_FRAME_POINTERS
40 select HAVE_DMA_CONTIGUOUS if !SWIOTLB
41 select HAVE_KRETPROBES
43 select HAVE_KPROBES_ON_FTRACE
44 select HAVE_FTRACE_MCOUNT_RECORD
45 select HAVE_FENTRY if X86_64
46 select HAVE_C_RECORDMCOUNT
47 select HAVE_DYNAMIC_FTRACE
48 select HAVE_DYNAMIC_FTRACE_WITH_REGS
49 select HAVE_FUNCTION_TRACER
50 select HAVE_FUNCTION_GRAPH_TRACER
51 select HAVE_FUNCTION_GRAPH_FP_TEST
52 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
53 select HAVE_SYSCALL_TRACEPOINTS
54 select SYSCTL_EXCEPTION_TRACE
57 select HAVE_ARCH_TRACEHOOK
58 select HAVE_GENERIC_DMA_COHERENT if X86_32
59 select HAVE_EFFICIENT_UNALIGNED_ACCESS
60 select USER_STACKTRACE_SUPPORT
61 select HAVE_REGS_AND_STACK_ACCESS_API
62 select HAVE_DMA_API_DEBUG
63 select HAVE_KERNEL_GZIP
64 select HAVE_KERNEL_BZIP2
65 select HAVE_KERNEL_LZMA
67 select HAVE_KERNEL_LZO
68 select HAVE_KERNEL_LZ4
69 select HAVE_HW_BREAKPOINT
70 select HAVE_MIXED_BREAKPOINTS_REGS
72 select HAVE_PERF_EVENTS_NMI
74 select HAVE_PERF_USER_STACK_DUMP
75 select HAVE_DEBUG_KMEMLEAK
77 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
78 select HAVE_CMPXCHG_LOCAL
79 select HAVE_CMPXCHG_DOUBLE
80 select HAVE_ARCH_KMEMCHECK
81 select HAVE_USER_RETURN_NOTIFIER
82 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
83 select HAVE_ARCH_JUMP_LABEL
84 select HAVE_TEXT_POKE_SMP
85 select HAVE_GENERIC_HARDIRQS
86 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
88 select GENERIC_FIND_FIRST_BIT
89 select GENERIC_IRQ_PROBE
90 select GENERIC_PENDING_IRQ if SMP
91 select GENERIC_IRQ_SHOW
92 select GENERIC_CLOCKEVENTS_MIN_ADJUST
93 select IRQ_FORCED_THREADING
94 select USE_GENERIC_SMP_HELPERS if SMP
95 select HAVE_BPF_JIT if X86_64
96 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
98 select ARCH_HAVE_NMI_SAFE_CMPXCHG
100 select DCACHE_WORD_ACCESS
101 select GENERIC_SMP_IDLE_THREAD
102 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
103 select HAVE_ARCH_SECCOMP_FILTER
104 select BUILDTIME_EXTABLE_SORT
105 select GENERIC_CMOS_UPDATE
106 select HAVE_ARCH_SOFT_DIRTY
107 select CLOCKSOURCE_WATCHDOG
108 select GENERIC_CLOCKEVENTS
109 select ARCH_CLOCKSOURCE_DATA if X86_64
110 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
111 select GENERIC_TIME_VSYSCALL if X86_64
112 select KTIME_SCALAR if X86_32
113 select GENERIC_STRNCPY_FROM_USER
114 select GENERIC_STRNLEN_USER
115 select HAVE_CONTEXT_TRACKING if X86_64
116 select HAVE_IRQ_TIME_ACCOUNTING
118 select MODULES_USE_ELF_REL if X86_32
119 select MODULES_USE_ELF_RELA if X86_64
120 select CLONE_BACKWARDS if X86_32
121 select ARCH_USE_BUILTIN_BSWAP
122 select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION
123 select OLD_SIGACTION if X86_32
124 select COMPAT_OLD_SIGACTION if IA32_EMULATION
126 select HAVE_DEBUG_STACKOVERFLOW
128 config INSTRUCTION_DECODER
130 depends on KPROBES || PERF_EVENTS || UPROBES
134 default "elf32-i386" if X86_32
135 default "elf64-x86-64" if X86_64
137 config ARCH_DEFCONFIG
139 default "arch/x86/configs/i386_defconfig" if X86_32
140 default "arch/x86/configs/x86_64_defconfig" if X86_64
142 config LOCKDEP_SUPPORT
145 config STACKTRACE_SUPPORT
148 config HAVE_LATENCYTOP_SUPPORT
157 config NEED_DMA_MAP_STATE
159 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
161 config NEED_SG_DMA_LENGTH
164 config GENERIC_ISA_DMA
166 depends on ISA_DMA_API
171 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
173 config GENERIC_BUG_RELATIVE_POINTERS
176 config GENERIC_HWEIGHT
179 config ARCH_MAY_HAVE_PC_FDC
181 depends on ISA_DMA_API
183 config RWSEM_XCHGADD_ALGORITHM
186 config GENERIC_CALIBRATE_DELAY
189 config ARCH_HAS_CPU_RELAX
192 config ARCH_HAS_CACHE_LINE_SIZE
195 config ARCH_HAS_CPU_AUTOPROBE
198 config HAVE_SETUP_PER_CPU_AREA
201 config NEED_PER_CPU_EMBED_FIRST_CHUNK
204 config NEED_PER_CPU_PAGE_FIRST_CHUNK
207 config ARCH_HIBERNATION_POSSIBLE
210 config ARCH_SUSPEND_POSSIBLE
213 config ARCH_WANT_HUGE_PMD_SHARE
216 config ARCH_WANT_GENERAL_HUGETLB
227 config ARCH_SUPPORTS_OPTIMIZED_INLINING
230 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
233 config HAVE_INTEL_TXT
235 depends on INTEL_IOMMU && ACPI
239 depends on X86_32 && SMP
243 depends on X86_64 && SMP
249 config X86_32_LAZY_GS
251 depends on X86_32 && !CC_STACKPROTECTOR
253 config ARCH_HWEIGHT_CFLAGS
255 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
256 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
258 config ARCH_CPU_PROBE_RELEASE
260 depends on HOTPLUG_CPU
262 config ARCH_SUPPORTS_UPROBES
265 source "init/Kconfig"
266 source "kernel/Kconfig.freezer"
268 menu "Processor type and features"
271 bool "DMA memory allocation support" if EXPERT
274 DMA memory allocation support allows devices with less than 32-bit
275 addressing to allocate within the first 16MB of address space.
276 Disable if no such devices will be used.
281 bool "Symmetric multi-processing support"
283 This enables support for systems with more than one CPU. If you have
284 a system with only one CPU, like most personal computers, say N. If
285 you have a system with more than one CPU, say Y.
287 If you say N here, the kernel will run on single and multiprocessor
288 machines, but will use only one CPU of a multiprocessor machine. If
289 you say Y here, the kernel will run on many, but not all,
290 singleprocessor machines. On a singleprocessor machine, the kernel
291 will run faster if you say N here.
293 Note that if you say Y here and choose architecture "586" or
294 "Pentium" under "Processor family", the kernel will not work on 486
295 architectures. Similarly, multiprocessor kernels for the "PPro"
296 architecture may not work on all Pentium based boards.
298 People using multiprocessor machines who say Y here should also say
299 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
300 Management" code will be disabled if you say Y here.
302 See also <file:Documentation/x86/i386/IO-APIC.txt>,
303 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
304 <http://www.tldp.org/docs.html#howto>.
306 If you don't know what to do here, say N.
309 bool "Support x2apic"
310 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
312 This enables x2apic support on CPUs that have this feature.
314 This allows 32-bit apic IDs (so it can support very large systems),
315 and accesses the local apic via MSRs not via mmio.
317 If you don't know what to do here, say N.
320 bool "Enable MPS table" if ACPI || SFI
322 depends on X86_LOCAL_APIC
324 For old smp systems that do not have proper acpi support. Newer systems
325 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
328 bool "Support for big SMP systems with more than 8 CPUs"
329 depends on X86_32 && SMP
331 This option is needed for the systems that have more than 8 CPUs
335 depends on X86_GOLDFISH
338 config X86_EXTENDED_PLATFORM
339 bool "Support for extended (non-PC) x86 platforms"
342 If you disable this option then the kernel will only support
343 standard PC platforms. (which covers the vast majority of
346 If you enable this option then you'll be able to select support
347 for the following (non-PC) 32 bit x86 platforms:
348 Goldfish (Android emulator)
352 SGI 320/540 (Visual Workstation)
353 STA2X11-based (e.g. Northville)
354 Summit/EXA (IBM x440)
355 Unisys ES7000 IA32 series
356 Moorestown MID devices
358 If you have one of these systems, or if you want to build a
359 generic distribution kernel, say Y here - otherwise say N.
363 config X86_EXTENDED_PLATFORM
364 bool "Support for extended (non-PC) x86 platforms"
367 If you disable this option then the kernel will only support
368 standard PC platforms. (which covers the vast majority of
371 If you enable this option then you'll be able to select support
372 for the following (non-PC) 64 bit x86 platforms:
377 If you have one of these systems, or if you want to build a
378 generic distribution kernel, say Y here - otherwise say N.
380 # This is an alphabetically sorted list of 64 bit extended platforms
381 # Please maintain the alphabetic order if and when there are additions
383 bool "Numascale NumaChip"
385 depends on X86_EXTENDED_PLATFORM
388 depends on X86_X2APIC
389 depends on PCI_MMCONFIG
391 Adds support for Numascale NumaChip large-SMP systems. Needed to
392 enable more than ~168 cores.
393 If you don't have one of these, you should say N here.
397 select HYPERVISOR_GUEST
399 depends on X86_64 && PCI
400 depends on X86_EXTENDED_PLATFORM
403 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
404 supposed to run on these EM64T-based machines. Only choose this option
405 if you have one of these machines.
408 bool "SGI Ultraviolet"
410 depends on X86_EXTENDED_PLATFORM
412 depends on X86_X2APIC
414 This option is needed in order to support SGI Ultraviolet systems.
415 If you don't have one of these, you should say N here.
417 # Following is an alphabetically sorted list of 32 bit extended platforms
418 # Please maintain the alphabetic order if and when there are additions
421 bool "Goldfish (Virtual Platform)"
423 depends on X86_EXTENDED_PLATFORM
425 Enable support for the Goldfish virtual platform used primarily
426 for Android development. Unless you are building for the Android
427 Goldfish emulator say N here.
430 bool "CE4100 TV platform"
432 depends on PCI_GODIRECT
434 depends on X86_EXTENDED_PLATFORM
435 select X86_REBOOTFIXUPS
437 select OF_EARLY_FLATTREE
440 Select for the Intel CE media processor (CE4100) SOC.
441 This option compiles in support for the CE4100 SOC for settop
442 boxes and media devices.
444 config X86_WANT_INTEL_MID
445 bool "Intel MID platform support"
447 depends on X86_EXTENDED_PLATFORM
449 Select to build a kernel capable of supporting Intel MID platform
450 systems which do not have the PCI legacy interfaces (Moorestown,
451 Medfield). If you are building for a PC class system say N here.
453 if X86_WANT_INTEL_MID
459 bool "Medfield MID platform"
462 depends on X86_IO_APIC
470 select X86_PLATFORM_DEVICES
471 select MFD_INTEL_MSIC
473 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
474 Internet Device(MID) platform.
475 Unlike standard x86 PCs, Medfield does not have many legacy devices
476 nor standard legacy replacement devices/features. e.g. Medfield does
477 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
481 config X86_INTEL_LPSS
482 bool "Intel Low Power Subsystem Support"
486 Select to build support for Intel Low Power Subsystem such as
487 found on Intel Lynxpoint PCH. Selecting this option enables
488 things like clock tree (common clock framework) which are needed
489 by the LPSS peripheral drivers.
492 bool "RDC R-321x SoC"
494 depends on X86_EXTENDED_PLATFORM
496 select X86_REBOOTFIXUPS
498 This option is needed for RDC R-321x system-on-chip, also known
500 If you don't have one of these chips, you should say N here.
502 config X86_32_NON_STANDARD
503 bool "Support non-standard 32-bit SMP architectures"
504 depends on X86_32 && SMP
505 depends on X86_EXTENDED_PLATFORM
507 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
508 STA2X11, default subarchitectures. It is intended for a generic
509 binary kernel. If you select them all, kernel will probe it
510 one by one and will fallback to default.
512 # Alphabetically sorted list of Non standard 32 bit platforms
515 bool "NUMAQ (IBM/Sequent)"
516 depends on X86_32_NON_STANDARD
521 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
522 NUMA multiquad box. This changes the way that processors are
523 bootstrapped, and uses Clustered Logical APIC addressing mode instead
524 of Flat Logical. You will need a new lynxer.elf file to flash your
525 firmware with - send email to <Martin.Bligh@us.ibm.com>.
527 config X86_SUPPORTS_MEMORY_FAILURE
529 # MCE code calls memory_failure():
531 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
532 depends on !X86_NUMAQ
533 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
534 depends on X86_64 || !SPARSEMEM
535 select ARCH_SUPPORTS_MEMORY_FAILURE
538 bool "SGI 320/540 (Visual Workstation)"
539 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
540 depends on X86_32_NON_STANDARD
542 The SGI Visual Workstation series is an IA32-based workstation
543 based on SGI systems chips with some legacy PC hardware attached.
545 Say Y here to create a kernel to run on the SGI 320 or 540.
547 A kernel compiled for the Visual Workstation will run on general
548 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
551 bool "STA2X11 Companion Chip Support"
552 depends on X86_32_NON_STANDARD && PCI
553 select X86_DEV_DMA_OPS
557 select ARCH_REQUIRE_GPIOLIB
560 This adds support for boards based on the STA2X11 IO-Hub,
561 a.k.a. "ConneXt". The chip is used in place of the standard
562 PC chipset, so all "standard" peripherals are missing. If this
563 option is selected the kernel will still be able to boot on
564 standard PC machines.
567 bool "Summit/EXA (IBM x440)"
568 depends on X86_32_NON_STANDARD
570 This option is needed for IBM systems that use the Summit/EXA chipset.
571 In particular, it is needed for the x440.
574 bool "Unisys ES7000 IA32 series"
575 depends on X86_32_NON_STANDARD && X86_BIGSMP
577 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
578 supposed to run on an IA32-based Unisys ES7000 system.
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 Unfortunately the downside is an up to 5% performance hit on
642 native kernels, with various workloads.
644 If you are unsure how to answer this question, answer N.
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
660 source "arch/x86/lguest/Kconfig"
662 config PARAVIRT_TIME_ACCOUNTING
663 bool "Paravirtual steal time accounting"
667 Select this option to enable fine granularity task steal time
668 accounting. Time spent executing other tasks in parallel with
669 the current vCPU is discounted from the vCPU power. To account for
670 that, there can be a small performance impact.
672 If in doubt, say N here.
674 config PARAVIRT_CLOCK
677 endif #HYPERVISOR_GUEST
685 This option adds a kernel parameter 'memtest', which allows memtest
687 memtest=0, mean disabled; -- default
688 memtest=1, mean do 1 test pattern;
690 memtest=4, mean do 4 test patterns.
691 If you are unsure how to answer this question, answer N.
693 config X86_SUMMIT_NUMA
695 depends on X86_32 && NUMA && X86_32_NON_STANDARD
697 config X86_CYCLONE_TIMER
699 depends on X86_SUMMIT
701 source "arch/x86/Kconfig.cpu"
705 prompt "HPET Timer Support" if X86_32
707 Use the IA-PC HPET (High Precision Event Timer) to manage
708 time in preference to the PIT and RTC, if a HPET is
710 HPET is the next generation timer replacing legacy 8254s.
711 The HPET provides a stable time base on SMP
712 systems, unlike the TSC, but it is more expensive to access,
713 as it is off-chip. You can find the HPET spec at
714 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
716 You can safely choose Y here. However, HPET will only be
717 activated if the platform and the BIOS support this feature.
718 Otherwise the 8254 will be used for timing services.
720 Choose N to continue using the legacy 8254 timer.
722 config HPET_EMULATE_RTC
724 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
727 def_bool y if X86_INTEL_MID
728 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
730 depends on X86_INTEL_MID && SFI
732 APB timer is the replacement for 8254, HPET on X86 MID platforms.
733 The APBT provides a stable time base on SMP
734 systems, unlike the TSC, but it is more expensive to access,
735 as it is off-chip. APB timers are always running regardless of CPU
736 C states, they are used as per CPU clockevent device when possible.
738 # Mark as expert because too many people got it wrong.
739 # The code disables itself when not needed.
742 bool "Enable DMI scanning" if EXPERT
744 Enabled scanning of DMI to identify machine quirks. Say Y
745 here unless you have verified that your setup is not
746 affected by entries in the DMI blacklist. Required by PNP
750 bool "GART IOMMU support" if EXPERT
753 depends on X86_64 && PCI && AMD_NB
755 Support for full DMA access of devices with 32bit memory access only
756 on systems with more than 3GB. This is usually needed for USB,
757 sound, many IDE/SATA chipsets and some other devices.
758 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
759 based hardware IOMMU and a software bounce buffer based IOMMU used
760 on Intel systems and as fallback.
761 The code is only active when needed (enough memory and limited
762 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
766 bool "IBM Calgary IOMMU support"
768 depends on X86_64 && PCI
770 Support for hardware IOMMUs in IBM's xSeries x366 and x460
771 systems. Needed to run systems with more than 3GB of memory
772 properly with 32-bit PCI devices that do not support DAC
773 (Double Address Cycle). Calgary also supports bus level
774 isolation, where all DMAs pass through the IOMMU. This
775 prevents them from going anywhere except their intended
776 destination. This catches hard-to-find kernel bugs and
777 mis-behaving drivers and devices that do not use the DMA-API
778 properly to set up their DMA buffers. The IOMMU can be
779 turned off at boot time with the iommu=off parameter.
780 Normally the kernel will make the right choice by itself.
783 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
785 prompt "Should Calgary be enabled by default?"
786 depends on CALGARY_IOMMU
788 Should Calgary be enabled by default? if you choose 'y', Calgary
789 will be used (if it exists). If you choose 'n', Calgary will not be
790 used even if it exists. If you choose 'n' and would like to use
791 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
794 # need this always selected by IOMMU for the VIA workaround
798 Support for software bounce buffers used on x86-64 systems
799 which don't have a hardware IOMMU. Using this PCI devices
800 which can only access 32-bits of memory can be used on systems
801 with more than 3 GB of memory.
806 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
809 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
810 depends on X86_64 && SMP && DEBUG_KERNEL
811 select CPUMASK_OFFSTACK
813 Enable maximum number of CPUS and NUMA Nodes for this architecture.
817 int "Maximum number of CPUs" if SMP && !MAXSMP
818 range 2 8 if SMP && X86_32 && !X86_BIGSMP
819 range 2 512 if SMP && !MAXSMP
821 default "4096" if MAXSMP
822 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
825 This allows you to specify the maximum number of CPUs which this
826 kernel will support. The maximum supported value is 512 and the
827 minimum value which makes sense is 2.
829 This is purely to save memory - each supported CPU adds
830 approximately eight kilobytes to the kernel image.
833 bool "SMT (Hyperthreading) scheduler support"
836 SMT scheduler support improves the CPU scheduler's decision making
837 when dealing with Intel Pentium 4 chips with HyperThreading at a
838 cost of slightly increased overhead in some places. If unsure say
843 prompt "Multi-core scheduler support"
846 Multi-core scheduler support improves the CPU scheduler's decision
847 making when dealing with multi-core CPU chips at a cost of slightly
848 increased overhead in some places. If unsure say N here.
850 source "kernel/Kconfig.preempt"
853 bool "Local APIC support on uniprocessors"
854 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
856 A local APIC (Advanced Programmable Interrupt Controller) is an
857 integrated interrupt controller in the CPU. If you have a single-CPU
858 system which has a processor with a local APIC, you can say Y here to
859 enable and use it. If you say Y here even though your machine doesn't
860 have a local APIC, then the kernel will still run with no slowdown at
861 all. The local APIC supports CPU-generated self-interrupts (timer,
862 performance counters), and the NMI watchdog which detects hard
866 bool "IO-APIC support on uniprocessors"
867 depends on X86_UP_APIC
869 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
870 SMP-capable replacement for PC-style interrupt controllers. Most
871 SMP systems and many recent uniprocessor systems have one.
873 If you have a single-CPU system with an IO-APIC, you can say Y here
874 to use it. If you say Y here even though your machine doesn't have
875 an IO-APIC, then the kernel will still run with no slowdown at all.
877 config X86_LOCAL_APIC
879 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
883 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
885 config X86_VISWS_APIC
887 depends on X86_32 && X86_VISWS
889 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
890 bool "Reroute for broken boot IRQs"
891 depends on X86_IO_APIC
893 This option enables a workaround that fixes a source of
894 spurious interrupts. This is recommended when threaded
895 interrupt handling is used on systems where the generation of
896 superfluous "boot interrupts" cannot be disabled.
898 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
899 entry in the chipset's IO-APIC is masked (as, e.g. the RT
900 kernel does during interrupt handling). On chipsets where this
901 boot IRQ generation cannot be disabled, this workaround keeps
902 the original IRQ line masked so that only the equivalent "boot
903 IRQ" is delivered to the CPUs. The workaround also tells the
904 kernel to set up the IRQ handler on the boot IRQ line. In this
905 way only one interrupt is delivered to the kernel. Otherwise
906 the spurious second interrupt may cause the kernel to bring
907 down (vital) interrupt lines.
909 Only affects "broken" chipsets. Interrupt sharing may be
910 increased on these systems.
913 bool "Machine Check / overheating reporting"
916 Machine Check support allows the processor to notify the
917 kernel if it detects a problem (e.g. overheating, data corruption).
918 The action the kernel takes depends on the severity of the problem,
919 ranging from warning messages to halting the machine.
923 prompt "Intel MCE features"
924 depends on X86_MCE && X86_LOCAL_APIC
926 Additional support for intel specific MCE features such as
931 prompt "AMD MCE features"
932 depends on X86_MCE && X86_LOCAL_APIC
934 Additional support for AMD specific MCE features such as
935 the DRAM Error Threshold.
937 config X86_ANCIENT_MCE
938 bool "Support for old Pentium 5 / WinChip machine checks"
939 depends on X86_32 && X86_MCE
941 Include support for machine check handling on old Pentium 5 or WinChip
942 systems. These typically need to be enabled explicitely on the command
945 config X86_MCE_THRESHOLD
946 depends on X86_MCE_AMD || X86_MCE_INTEL
949 config X86_MCE_INJECT
951 tristate "Machine check injector support"
953 Provide support for injecting machine checks for testing purposes.
954 If you don't know what a machine check is and you don't do kernel
955 QA it is safe to say n.
957 config X86_THERMAL_VECTOR
959 depends on X86_MCE_INTEL
962 bool "Enable VM86 support" if EXPERT
966 This option is required by programs like DOSEMU to run 16-bit legacy
967 code on X86 processors. It also may be needed by software like
968 XFree86 to initialize some video cards via BIOS. Disabling this
969 option saves about 6k.
972 tristate "Toshiba Laptop support"
975 This adds a driver to safely access the System Management Mode of
976 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
977 not work on models with a Phoenix BIOS. The System Management Mode
978 is used to set the BIOS and power saving options on Toshiba portables.
980 For information on utilities to make use of this driver see the
981 Toshiba Linux utilities web site at:
982 <http://www.buzzard.org.uk/toshiba/>.
984 Say Y if you intend to run this kernel on a Toshiba portable.
988 tristate "Dell laptop support"
991 This adds a driver to safely access the System Management Mode
992 of the CPU on the Dell Inspiron 8000. The System Management Mode
993 is used to read cpu temperature and cooling fan status and to
994 control the fans on the I8K portables.
996 This driver has been tested only on the Inspiron 8000 but it may
997 also work with other Dell laptops. You can force loading on other
998 models by passing the parameter `force=1' to the module. Use at
1001 For information on utilities to make use of this driver see the
1002 I8K Linux utilities web site at:
1003 <http://people.debian.org/~dz/i8k/>
1005 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
1008 config X86_REBOOTFIXUPS
1009 bool "Enable X86 board specific fixups for reboot"
1012 This enables chipset and/or board specific fixups to be done
1013 in order to get reboot to work correctly. This is only needed on
1014 some combinations of hardware and BIOS. The symptom, for which
1015 this config is intended, is when reboot ends with a stalled/hung
1018 Currently, the only fixup is for the Geode machines using
1019 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1021 Say Y if you want to enable the fixup. Currently, it's safe to
1022 enable this option even if you don't need it.
1026 tristate "CPU microcode loading support"
1030 If you say Y here, you will be able to update the microcode on
1031 certain Intel and AMD processors. The Intel support is for the
1032 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4,
1033 Xeon etc. The AMD support is for families 0x10 and later. You will
1034 obviously need the actual microcode binary data itself which is not
1035 shipped with the Linux kernel.
1037 This option selects the general module only, you need to select
1038 at least one vendor specific module as well.
1040 To compile this driver as a module, choose M here: the module
1041 will be called microcode.
1043 config MICROCODE_INTEL
1044 bool "Intel microcode loading support"
1045 depends on MICROCODE
1049 This options enables microcode patch loading support for Intel
1052 For latest news and information on obtaining all the required
1053 Intel ingredients for this driver, check:
1054 <http://www.urbanmyth.org/microcode/>.
1056 config MICROCODE_AMD
1057 bool "AMD microcode loading support"
1058 depends on MICROCODE
1061 If you select this option, microcode patch loading support for AMD
1062 processors will be enabled.
1064 config MICROCODE_OLD_INTERFACE
1066 depends on MICROCODE
1068 config MICROCODE_INTEL_LIB
1070 depends on MICROCODE_INTEL
1072 config MICROCODE_INTEL_EARLY
1075 config MICROCODE_AMD_EARLY
1078 config MICROCODE_EARLY
1079 bool "Early load microcode"
1080 depends on MICROCODE=y && BLK_DEV_INITRD
1081 select MICROCODE_INTEL_EARLY if MICROCODE_INTEL
1082 select MICROCODE_AMD_EARLY if MICROCODE_AMD
1085 This option provides functionality to read additional microcode data
1086 at the beginning of initrd image. The data tells kernel to load
1087 microcode to CPU's as early as possible. No functional change if no
1088 microcode data is glued to the initrd, therefore it's safe to say Y.
1091 tristate "/dev/cpu/*/msr - Model-specific register support"
1093 This device gives privileged processes access to the x86
1094 Model-Specific Registers (MSRs). It is a character device with
1095 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1096 MSR accesses are directed to a specific CPU on multi-processor
1100 tristate "/dev/cpu/*/cpuid - CPU information support"
1102 This device gives processes access to the x86 CPUID instruction to
1103 be executed on a specific processor. It is a character device
1104 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1108 prompt "High Memory Support"
1109 default HIGHMEM64G if X86_NUMAQ
1115 depends on !X86_NUMAQ
1117 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1118 However, the address space of 32-bit x86 processors is only 4
1119 Gigabytes large. That means that, if you have a large amount of
1120 physical memory, not all of it can be "permanently mapped" by the
1121 kernel. The physical memory that's not permanently mapped is called
1124 If you are compiling a kernel which will never run on a machine with
1125 more than 1 Gigabyte total physical RAM, answer "off" here (default
1126 choice and suitable for most users). This will result in a "3GB/1GB"
1127 split: 3GB are mapped so that each process sees a 3GB virtual memory
1128 space and the remaining part of the 4GB virtual memory space is used
1129 by the kernel to permanently map as much physical memory as
1132 If the machine has between 1 and 4 Gigabytes physical RAM, then
1135 If more than 4 Gigabytes is used then answer "64GB" here. This
1136 selection turns Intel PAE (Physical Address Extension) mode on.
1137 PAE implements 3-level paging on IA32 processors. PAE is fully
1138 supported by Linux, PAE mode is implemented on all recent Intel
1139 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1140 then the kernel will not boot on CPUs that don't support PAE!
1142 The actual amount of total physical memory will either be
1143 auto detected or can be forced by using a kernel command line option
1144 such as "mem=256M". (Try "man bootparam" or see the documentation of
1145 your boot loader (lilo or loadlin) about how to pass options to the
1146 kernel at boot time.)
1148 If unsure, say "off".
1152 depends on !X86_NUMAQ
1154 Select this if you have a 32-bit processor and between 1 and 4
1155 gigabytes of physical RAM.
1162 Select this if you have a 32-bit processor and more than 4
1163 gigabytes of physical RAM.
1168 prompt "Memory split" if EXPERT
1172 Select the desired split between kernel and user memory.
1174 If the address range available to the kernel is less than the
1175 physical memory installed, the remaining memory will be available
1176 as "high memory". Accessing high memory is a little more costly
1177 than low memory, as it needs to be mapped into the kernel first.
1178 Note that increasing the kernel address space limits the range
1179 available to user programs, making the address space there
1180 tighter. Selecting anything other than the default 3G/1G split
1181 will also likely make your kernel incompatible with binary-only
1184 If you are not absolutely sure what you are doing, leave this
1188 bool "3G/1G user/kernel split"
1189 config VMSPLIT_3G_OPT
1191 bool "3G/1G user/kernel split (for full 1G low memory)"
1193 bool "2G/2G user/kernel split"
1194 config VMSPLIT_2G_OPT
1196 bool "2G/2G user/kernel split (for full 2G low memory)"
1198 bool "1G/3G user/kernel split"
1203 default 0xB0000000 if VMSPLIT_3G_OPT
1204 default 0x80000000 if VMSPLIT_2G
1205 default 0x78000000 if VMSPLIT_2G_OPT
1206 default 0x40000000 if VMSPLIT_1G
1212 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1215 bool "PAE (Physical Address Extension) Support"
1216 depends on X86_32 && !HIGHMEM4G
1218 PAE is required for NX support, and furthermore enables
1219 larger swapspace support for non-overcommit purposes. It
1220 has the cost of more pagetable lookup overhead, and also
1221 consumes more pagetable space per process.
1223 config ARCH_PHYS_ADDR_T_64BIT
1225 depends on X86_64 || X86_PAE
1227 config ARCH_DMA_ADDR_T_64BIT
1229 depends on X86_64 || HIGHMEM64G
1231 config DIRECT_GBPAGES
1232 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1236 Allow the kernel linear mapping to use 1GB pages on CPUs that
1237 support it. This can improve the kernel's performance a tiny bit by
1238 reducing TLB pressure. If in doubt, say "Y".
1240 # Common NUMA Features
1242 bool "Numa Memory Allocation and Scheduler Support"
1244 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI))
1245 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1247 Enable NUMA (Non Uniform Memory Access) support.
1249 The kernel will try to allocate memory used by a CPU on the
1250 local memory controller of the CPU and add some more
1251 NUMA awareness to the kernel.
1253 For 64-bit this is recommended if the system is Intel Core i7
1254 (or later), AMD Opteron, or EM64T NUMA.
1256 For 32-bit this is only needed on (rare) 32-bit-only platforms
1257 that support NUMA topologies, such as NUMAQ / Summit, or if you
1258 boot a 32-bit kernel on a 64-bit NUMA platform.
1260 Otherwise, you should say N.
1262 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1263 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1267 prompt "Old style AMD Opteron NUMA detection"
1268 depends on X86_64 && NUMA && PCI
1270 Enable AMD NUMA node topology detection. You should say Y here if
1271 you have a multi processor AMD system. This uses an old method to
1272 read the NUMA configuration directly from the builtin Northbridge
1273 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1274 which also takes priority if both are compiled in.
1276 config X86_64_ACPI_NUMA
1278 prompt "ACPI NUMA detection"
1279 depends on X86_64 && NUMA && ACPI && PCI
1282 Enable ACPI SRAT based node topology detection.
1284 # Some NUMA nodes have memory ranges that span
1285 # other nodes. Even though a pfn is valid and
1286 # between a node's start and end pfns, it may not
1287 # reside on that node. See memmap_init_zone()
1289 config NODES_SPAN_OTHER_NODES
1291 depends on X86_64_ACPI_NUMA
1294 bool "NUMA emulation"
1297 Enable NUMA emulation. A flat machine will be split
1298 into virtual nodes when booted with "numa=fake=N", where N is the
1299 number of nodes. This is only useful for debugging.
1302 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1304 default "10" if MAXSMP
1305 default "6" if X86_64
1306 default "4" if X86_NUMAQ
1308 depends on NEED_MULTIPLE_NODES
1310 Specify the maximum number of NUMA Nodes available on the target
1311 system. Increases memory reserved to accommodate various tables.
1313 config ARCH_HAVE_MEMORY_PRESENT
1315 depends on X86_32 && DISCONTIGMEM
1317 config NEED_NODE_MEMMAP_SIZE
1319 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1321 config ARCH_FLATMEM_ENABLE
1323 depends on X86_32 && !NUMA
1325 config ARCH_DISCONTIGMEM_ENABLE
1327 depends on NUMA && X86_32
1329 config ARCH_DISCONTIGMEM_DEFAULT
1331 depends on NUMA && X86_32
1333 config ARCH_SPARSEMEM_ENABLE
1335 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1336 select SPARSEMEM_STATIC if X86_32
1337 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1339 config ARCH_SPARSEMEM_DEFAULT
1343 config ARCH_SELECT_MEMORY_MODEL
1345 depends on ARCH_SPARSEMEM_ENABLE
1347 config ARCH_MEMORY_PROBE
1349 depends on X86_64 && MEMORY_HOTPLUG
1351 config ARCH_PROC_KCORE_TEXT
1353 depends on X86_64 && PROC_KCORE
1355 config ILLEGAL_POINTER_VALUE
1358 default 0xdead000000000000 if X86_64
1363 bool "Allocate 3rd-level pagetables from highmem"
1366 The VM uses one page table entry for each page of physical memory.
1367 For systems with a lot of RAM, this can be wasteful of precious
1368 low memory. Setting this option will put user-space page table
1369 entries in high memory.
1371 config X86_CHECK_BIOS_CORRUPTION
1372 bool "Check for low memory corruption"
1374 Periodically check for memory corruption in low memory, which
1375 is suspected to be caused by BIOS. Even when enabled in the
1376 configuration, it is disabled at runtime. Enable it by
1377 setting "memory_corruption_check=1" on the kernel command
1378 line. By default it scans the low 64k of memory every 60
1379 seconds; see the memory_corruption_check_size and
1380 memory_corruption_check_period parameters in
1381 Documentation/kernel-parameters.txt to adjust this.
1383 When enabled with the default parameters, this option has
1384 almost no overhead, as it reserves a relatively small amount
1385 of memory and scans it infrequently. It both detects corruption
1386 and prevents it from affecting the running system.
1388 It is, however, intended as a diagnostic tool; if repeatable
1389 BIOS-originated corruption always affects the same memory,
1390 you can use memmap= to prevent the kernel from using that
1393 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1394 bool "Set the default setting of memory_corruption_check"
1395 depends on X86_CHECK_BIOS_CORRUPTION
1398 Set whether the default state of memory_corruption_check is
1401 config X86_RESERVE_LOW
1402 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1406 Specify the amount of low memory to reserve for the BIOS.
1408 The first page contains BIOS data structures that the kernel
1409 must not use, so that page must always be reserved.
1411 By default we reserve the first 64K of physical RAM, as a
1412 number of BIOSes are known to corrupt that memory range
1413 during events such as suspend/resume or monitor cable
1414 insertion, so it must not be used by the kernel.
1416 You can set this to 4 if you are absolutely sure that you
1417 trust the BIOS to get all its memory reservations and usages
1418 right. If you know your BIOS have problems beyond the
1419 default 64K area, you can set this to 640 to avoid using the
1420 entire low memory range.
1422 If you have doubts about the BIOS (e.g. suspend/resume does
1423 not work or there's kernel crashes after certain hardware
1424 hotplug events) then you might want to enable
1425 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1426 typical corruption patterns.
1428 Leave this to the default value of 64 if you are unsure.
1430 config MATH_EMULATION
1432 prompt "Math emulation" if X86_32
1434 Linux can emulate a math coprocessor (used for floating point
1435 operations) if you don't have one. 486DX and Pentium processors have
1436 a math coprocessor built in, 486SX and 386 do not, unless you added
1437 a 487DX or 387, respectively. (The messages during boot time can
1438 give you some hints here ["man dmesg"].) Everyone needs either a
1439 coprocessor or this emulation.
1441 If you don't have a math coprocessor, you need to say Y here; if you
1442 say Y here even though you have a coprocessor, the coprocessor will
1443 be used nevertheless. (This behavior can be changed with the kernel
1444 command line option "no387", which comes handy if your coprocessor
1445 is broken. Try "man bootparam" or see the documentation of your boot
1446 loader (lilo or loadlin) about how to pass options to the kernel at
1447 boot time.) This means that it is a good idea to say Y here if you
1448 intend to use this kernel on different machines.
1450 More information about the internals of the Linux math coprocessor
1451 emulation can be found in <file:arch/x86/math-emu/README>.
1453 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1454 kernel, it won't hurt.
1458 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1460 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1461 the Memory Type Range Registers (MTRRs) may be used to control
1462 processor access to memory ranges. This is most useful if you have
1463 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1464 allows bus write transfers to be combined into a larger transfer
1465 before bursting over the PCI/AGP bus. This can increase performance
1466 of image write operations 2.5 times or more. Saying Y here creates a
1467 /proc/mtrr file which may be used to manipulate your processor's
1468 MTRRs. Typically the X server should use this.
1470 This code has a reasonably generic interface so that similar
1471 control registers on other processors can be easily supported
1474 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1475 Registers (ARRs) which provide a similar functionality to MTRRs. For
1476 these, the ARRs are used to emulate the MTRRs.
1477 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1478 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1479 write-combining. All of these processors are supported by this code
1480 and it makes sense to say Y here if you have one of them.
1482 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1483 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1484 can lead to all sorts of problems, so it's good to say Y here.
1486 You can safely say Y even if your machine doesn't have MTRRs, you'll
1487 just add about 9 KB to your kernel.
1489 See <file:Documentation/x86/mtrr.txt> for more information.
1491 config MTRR_SANITIZER
1493 prompt "MTRR cleanup support"
1496 Convert MTRR layout from continuous to discrete, so X drivers can
1497 add writeback entries.
1499 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1500 The largest mtrr entry size for a continuous block can be set with
1505 config MTRR_SANITIZER_ENABLE_DEFAULT
1506 int "MTRR cleanup enable value (0-1)"
1509 depends on MTRR_SANITIZER
1511 Enable mtrr cleanup default value
1513 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1514 int "MTRR cleanup spare reg num (0-7)"
1517 depends on MTRR_SANITIZER
1519 mtrr cleanup spare entries default, it can be changed via
1520 mtrr_spare_reg_nr=N on the kernel command line.
1524 prompt "x86 PAT support" if EXPERT
1527 Use PAT attributes to setup page level cache control.
1529 PATs are the modern equivalents of MTRRs and are much more
1530 flexible than MTRRs.
1532 Say N here if you see bootup problems (boot crash, boot hang,
1533 spontaneous reboots) or a non-working video driver.
1537 config ARCH_USES_PG_UNCACHED
1543 prompt "x86 architectural random number generator" if EXPERT
1545 Enable the x86 architectural RDRAND instruction
1546 (Intel Bull Mountain technology) to generate random numbers.
1547 If supported, this is a high bandwidth, cryptographically
1548 secure hardware random number generator.
1552 prompt "Supervisor Mode Access Prevention" if EXPERT
1554 Supervisor Mode Access Prevention (SMAP) is a security
1555 feature in newer Intel processors. There is a small
1556 performance cost if this enabled and turned on; there is
1557 also a small increase in the kernel size if this is enabled.
1562 bool "EFI runtime service support"
1566 This enables the kernel to use EFI runtime services that are
1567 available (such as the EFI variable services).
1569 This option is only useful on systems that have EFI firmware.
1570 In addition, you should use the latest ELILO loader available
1571 at <http://elilo.sourceforge.net> in order to take advantage
1572 of EFI runtime services. However, even with this option, the
1573 resultant kernel should continue to boot on existing non-EFI
1577 bool "EFI stub support"
1580 This kernel feature allows a bzImage to be loaded directly
1581 by EFI firmware without the use of a bootloader.
1583 See Documentation/x86/efi-stub.txt for more information.
1587 prompt "Enable seccomp to safely compute untrusted bytecode"
1589 This kernel feature is useful for number crunching applications
1590 that may need to compute untrusted bytecode during their
1591 execution. By using pipes or other transports made available to
1592 the process as file descriptors supporting the read/write
1593 syscalls, it's possible to isolate those applications in
1594 their own address space using seccomp. Once seccomp is
1595 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1596 and the task is only allowed to execute a few safe syscalls
1597 defined by each seccomp mode.
1599 If unsure, say Y. Only embedded should say N here.
1601 config CC_STACKPROTECTOR
1602 bool "Enable -fstack-protector buffer overflow detection"
1604 This option turns on the -fstack-protector GCC feature. This
1605 feature puts, at the beginning of functions, a canary value on
1606 the stack just before the return address, and validates
1607 the value just before actually returning. Stack based buffer
1608 overflows (that need to overwrite this return address) now also
1609 overwrite the canary, which gets detected and the attack is then
1610 neutralized via a kernel panic.
1612 This feature requires gcc version 4.2 or above, or a distribution
1613 gcc with the feature backported. Older versions are automatically
1614 detected and for those versions, this configuration option is
1615 ignored. (and a warning is printed during bootup)
1617 source kernel/Kconfig.hz
1620 bool "kexec system call"
1622 kexec is a system call that implements the ability to shutdown your
1623 current kernel, and to start another kernel. It is like a reboot
1624 but it is independent of the system firmware. And like a reboot
1625 you can start any kernel with it, not just Linux.
1627 The name comes from the similarity to the exec system call.
1629 It is an ongoing process to be certain the hardware in a machine
1630 is properly shutdown, so do not be surprised if this code does not
1631 initially work for you. It may help to enable device hotplugging
1632 support. As of this writing the exact hardware interface is
1633 strongly in flux, so no good recommendation can be made.
1636 bool "kernel crash dumps"
1637 depends on X86_64 || (X86_32 && HIGHMEM)
1639 Generate crash dump after being started by kexec.
1640 This should be normally only set in special crash dump kernels
1641 which are loaded in the main kernel with kexec-tools into
1642 a specially reserved region and then later executed after
1643 a crash by kdump/kexec. The crash dump kernel must be compiled
1644 to a memory address not used by the main kernel or BIOS using
1645 PHYSICAL_START, or it must be built as a relocatable image
1646 (CONFIG_RELOCATABLE=y).
1647 For more details see Documentation/kdump/kdump.txt
1651 depends on KEXEC && HIBERNATION
1653 Jump between original kernel and kexeced kernel and invoke
1654 code in physical address mode via KEXEC
1656 config PHYSICAL_START
1657 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1660 This gives the physical address where the kernel is loaded.
1662 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1663 bzImage will decompress itself to above physical address and
1664 run from there. Otherwise, bzImage will run from the address where
1665 it has been loaded by the boot loader and will ignore above physical
1668 In normal kdump cases one does not have to set/change this option
1669 as now bzImage can be compiled as a completely relocatable image
1670 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1671 address. This option is mainly useful for the folks who don't want
1672 to use a bzImage for capturing the crash dump and want to use a
1673 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1674 to be specifically compiled to run from a specific memory area
1675 (normally a reserved region) and this option comes handy.
1677 So if you are using bzImage for capturing the crash dump,
1678 leave the value here unchanged to 0x1000000 and set
1679 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1680 for capturing the crash dump change this value to start of
1681 the reserved region. In other words, it can be set based on
1682 the "X" value as specified in the "crashkernel=YM@XM"
1683 command line boot parameter passed to the panic-ed
1684 kernel. Please take a look at Documentation/kdump/kdump.txt
1685 for more details about crash dumps.
1687 Usage of bzImage for capturing the crash dump is recommended as
1688 one does not have to build two kernels. Same kernel can be used
1689 as production kernel and capture kernel. Above option should have
1690 gone away after relocatable bzImage support is introduced. But it
1691 is present because there are users out there who continue to use
1692 vmlinux for dump capture. This option should go away down the
1695 Don't change this unless you know what you are doing.
1698 bool "Build a relocatable kernel"
1701 This builds a kernel image that retains relocation information
1702 so it can be loaded someplace besides the default 1MB.
1703 The relocations tend to make the kernel binary about 10% larger,
1704 but are discarded at runtime.
1706 One use is for the kexec on panic case where the recovery kernel
1707 must live at a different physical address than the primary
1710 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1711 it has been loaded at and the compile time physical address
1712 (CONFIG_PHYSICAL_START) is ignored.
1714 # Relocation on x86-32 needs some additional build support
1715 config X86_NEED_RELOCS
1717 depends on X86_32 && RELOCATABLE
1719 config PHYSICAL_ALIGN
1720 hex "Alignment value to which kernel should be aligned" if X86_32
1722 range 0x2000 0x1000000
1724 This value puts the alignment restrictions on physical address
1725 where kernel is loaded and run from. Kernel is compiled for an
1726 address which meets above alignment restriction.
1728 If bootloader loads the kernel at a non-aligned address and
1729 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1730 address aligned to above value and run from there.
1732 If bootloader loads the kernel at a non-aligned address and
1733 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1734 load address and decompress itself to the address it has been
1735 compiled for and run from there. The address for which kernel is
1736 compiled already meets above alignment restrictions. Hence the
1737 end result is that kernel runs from a physical address meeting
1738 above alignment restrictions.
1740 Don't change this unless you know what you are doing.
1743 bool "Support for hot-pluggable CPUs"
1746 Say Y here to allow turning CPUs off and on. CPUs can be
1747 controlled through /sys/devices/system/cpu.
1748 ( Note: power management support will enable this option
1749 automatically on SMP systems. )
1750 Say N if you want to disable CPU hotplug.
1752 config BOOTPARAM_HOTPLUG_CPU0
1753 bool "Set default setting of cpu0_hotpluggable"
1755 depends on HOTPLUG_CPU
1757 Set whether default state of cpu0_hotpluggable is on or off.
1759 Say Y here to enable CPU0 hotplug by default. If this switch
1760 is turned on, there is no need to give cpu0_hotplug kernel
1761 parameter and the CPU0 hotplug feature is enabled by default.
1763 Please note: there are two known CPU0 dependencies if you want
1764 to enable the CPU0 hotplug feature either by this switch or by
1765 cpu0_hotplug kernel parameter.
1767 First, resume from hibernate or suspend always starts from CPU0.
1768 So hibernate and suspend are prevented if CPU0 is offline.
1770 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1771 offline if any interrupt can not migrate out of CPU0. There may
1772 be other CPU0 dependencies.
1774 Please make sure the dependencies are under your control before
1775 you enable this feature.
1777 Say N if you don't want to enable CPU0 hotplug feature by default.
1778 You still can enable the CPU0 hotplug feature at boot by kernel
1779 parameter cpu0_hotplug.
1781 config DEBUG_HOTPLUG_CPU0
1783 prompt "Debug CPU0 hotplug"
1784 depends on HOTPLUG_CPU
1786 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1787 soon as possible and boots up userspace with CPU0 offlined. User
1788 can online CPU0 back after boot time.
1790 To debug CPU0 hotplug, you need to enable CPU0 offline/online
1791 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1792 compilation or giving cpu0_hotplug kernel parameter at boot.
1798 prompt "Compat VDSO support"
1799 depends on X86_32 || IA32_EMULATION
1801 Map the 32-bit VDSO to the predictable old-style address too.
1803 Say N here if you are running a sufficiently recent glibc
1804 version (2.3.3 or later), to remove the high-mapped
1805 VDSO mapping and to exclusively use the randomized VDSO.
1810 bool "Built-in kernel command line"
1812 Allow for specifying boot arguments to the kernel at
1813 build time. On some systems (e.g. embedded ones), it is
1814 necessary or convenient to provide some or all of the
1815 kernel boot arguments with the kernel itself (that is,
1816 to not rely on the boot loader to provide them.)
1818 To compile command line arguments into the kernel,
1819 set this option to 'Y', then fill in the
1820 the boot arguments in CONFIG_CMDLINE.
1822 Systems with fully functional boot loaders (i.e. non-embedded)
1823 should leave this option set to 'N'.
1826 string "Built-in kernel command string"
1827 depends on CMDLINE_BOOL
1830 Enter arguments here that should be compiled into the kernel
1831 image and used at boot time. If the boot loader provides a
1832 command line at boot time, it is appended to this string to
1833 form the full kernel command line, when the system boots.
1835 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1836 change this behavior.
1838 In most cases, the command line (whether built-in or provided
1839 by the boot loader) should specify the device for the root
1842 config CMDLINE_OVERRIDE
1843 bool "Built-in command line overrides boot loader arguments"
1844 depends on CMDLINE_BOOL
1846 Set this option to 'Y' to have the kernel ignore the boot loader
1847 command line, and use ONLY the built-in command line.
1849 This is used to work around broken boot loaders. This should
1850 be set to 'N' under normal conditions.
1854 config ARCH_ENABLE_MEMORY_HOTPLUG
1856 depends on X86_64 || (X86_32 && HIGHMEM)
1858 config ARCH_ENABLE_MEMORY_HOTREMOVE
1860 depends on MEMORY_HOTPLUG
1862 config USE_PERCPU_NUMA_NODE_ID
1866 menu "Power management and ACPI options"
1868 config ARCH_HIBERNATION_HEADER
1870 depends on X86_64 && HIBERNATION
1872 source "kernel/power/Kconfig"
1874 source "drivers/acpi/Kconfig"
1876 source "drivers/sfi/Kconfig"
1883 tristate "APM (Advanced Power Management) BIOS support"
1884 depends on X86_32 && PM_SLEEP
1886 APM is a BIOS specification for saving power using several different
1887 techniques. This is mostly useful for battery powered laptops with
1888 APM compliant BIOSes. If you say Y here, the system time will be
1889 reset after a RESUME operation, the /proc/apm device will provide
1890 battery status information, and user-space programs will receive
1891 notification of APM "events" (e.g. battery status change).
1893 If you select "Y" here, you can disable actual use of the APM
1894 BIOS by passing the "apm=off" option to the kernel at boot time.
1896 Note that the APM support is almost completely disabled for
1897 machines with more than one CPU.
1899 In order to use APM, you will need supporting software. For location
1900 and more information, read <file:Documentation/power/apm-acpi.txt>
1901 and the Battery Powered Linux mini-HOWTO, available from
1902 <http://www.tldp.org/docs.html#howto>.
1904 This driver does not spin down disk drives (see the hdparm(8)
1905 manpage ("man 8 hdparm") for that), and it doesn't turn off
1906 VESA-compliant "green" monitors.
1908 This driver does not support the TI 4000M TravelMate and the ACER
1909 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1910 desktop machines also don't have compliant BIOSes, and this driver
1911 may cause those machines to panic during the boot phase.
1913 Generally, if you don't have a battery in your machine, there isn't
1914 much point in using this driver and you should say N. If you get
1915 random kernel OOPSes or reboots that don't seem to be related to
1916 anything, try disabling/enabling this option (or disabling/enabling
1919 Some other things you should try when experiencing seemingly random,
1922 1) make sure that you have enough swap space and that it is
1924 2) pass the "no-hlt" option to the kernel
1925 3) switch on floating point emulation in the kernel and pass
1926 the "no387" option to the kernel
1927 4) pass the "floppy=nodma" option to the kernel
1928 5) pass the "mem=4M" option to the kernel (thereby disabling
1929 all but the first 4 MB of RAM)
1930 6) make sure that the CPU is not over clocked.
1931 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1932 8) disable the cache from your BIOS settings
1933 9) install a fan for the video card or exchange video RAM
1934 10) install a better fan for the CPU
1935 11) exchange RAM chips
1936 12) exchange the motherboard.
1938 To compile this driver as a module, choose M here: the
1939 module will be called apm.
1943 config APM_IGNORE_USER_SUSPEND
1944 bool "Ignore USER SUSPEND"
1946 This option will ignore USER SUSPEND requests. On machines with a
1947 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1948 series notebooks, it is necessary to say Y because of a BIOS bug.
1950 config APM_DO_ENABLE
1951 bool "Enable PM at boot time"
1953 Enable APM features at boot time. From page 36 of the APM BIOS
1954 specification: "When disabled, the APM BIOS does not automatically
1955 power manage devices, enter the Standby State, enter the Suspend
1956 State, or take power saving steps in response to CPU Idle calls."
1957 This driver will make CPU Idle calls when Linux is idle (unless this
1958 feature is turned off -- see "Do CPU IDLE calls", below). This
1959 should always save battery power, but more complicated APM features
1960 will be dependent on your BIOS implementation. You may need to turn
1961 this option off if your computer hangs at boot time when using APM
1962 support, or if it beeps continuously instead of suspending. Turn
1963 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1964 T400CDT. This is off by default since most machines do fine without
1969 bool "Make CPU Idle calls when idle"
1971 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1972 On some machines, this can activate improved power savings, such as
1973 a slowed CPU clock rate, when the machine is idle. These idle calls
1974 are made after the idle loop has run for some length of time (e.g.,
1975 333 mS). On some machines, this will cause a hang at boot time or
1976 whenever the CPU becomes idle. (On machines with more than one CPU,
1977 this option does nothing.)
1979 config APM_DISPLAY_BLANK
1980 bool "Enable console blanking using APM"
1982 Enable console blanking using the APM. Some laptops can use this to
1983 turn off the LCD backlight when the screen blanker of the Linux
1984 virtual console blanks the screen. Note that this is only used by
1985 the virtual console screen blanker, and won't turn off the backlight
1986 when using the X Window system. This also doesn't have anything to
1987 do with your VESA-compliant power-saving monitor. Further, this
1988 option doesn't work for all laptops -- it might not turn off your
1989 backlight at all, or it might print a lot of errors to the console,
1990 especially if you are using gpm.
1992 config APM_ALLOW_INTS
1993 bool "Allow interrupts during APM BIOS calls"
1995 Normally we disable external interrupts while we are making calls to
1996 the APM BIOS as a measure to lessen the effects of a badly behaving
1997 BIOS implementation. The BIOS should reenable interrupts if it
1998 needs to. Unfortunately, some BIOSes do not -- especially those in
1999 many of the newer IBM Thinkpads. If you experience hangs when you
2000 suspend, try setting this to Y. Otherwise, say N.
2004 source "drivers/cpufreq/Kconfig"
2006 source "drivers/cpuidle/Kconfig"
2008 source "drivers/idle/Kconfig"
2013 menu "Bus options (PCI etc.)"
2018 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
2020 Find out whether you have a PCI motherboard. PCI is the name of a
2021 bus system, i.e. the way the CPU talks to the other stuff inside
2022 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2023 VESA. If you have PCI, say Y, otherwise N.
2026 prompt "PCI access mode"
2027 depends on X86_32 && PCI
2030 On PCI systems, the BIOS can be used to detect the PCI devices and
2031 determine their configuration. However, some old PCI motherboards
2032 have BIOS bugs and may crash if this is done. Also, some embedded
2033 PCI-based systems don't have any BIOS at all. Linux can also try to
2034 detect the PCI hardware directly without using the BIOS.
2036 With this option, you can specify how Linux should detect the
2037 PCI devices. If you choose "BIOS", the BIOS will be used,
2038 if you choose "Direct", the BIOS won't be used, and if you
2039 choose "MMConfig", then PCI Express MMCONFIG will be used.
2040 If you choose "Any", the kernel will try MMCONFIG, then the
2041 direct access method and falls back to the BIOS if that doesn't
2042 work. If unsure, go with the default, which is "Any".
2047 config PCI_GOMMCONFIG
2064 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2066 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2069 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2073 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2077 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2081 depends on PCI && XEN
2089 bool "Support mmconfig PCI config space access"
2090 depends on X86_64 && PCI && ACPI
2092 config PCI_CNB20LE_QUIRK
2093 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2096 Read the PCI windows out of the CNB20LE host bridge. This allows
2097 PCI hotplug to work on systems with the CNB20LE chipset which do
2100 There's no public spec for this chipset, and this functionality
2101 is known to be incomplete.
2103 You should say N unless you know you need this.
2105 source "drivers/pci/pcie/Kconfig"
2107 source "drivers/pci/Kconfig"
2109 # x86_64 have no ISA slots, but can have ISA-style DMA.
2111 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2114 Enables ISA-style DMA support for devices requiring such controllers.
2122 Find out whether you have ISA slots on your motherboard. ISA is the
2123 name of a bus system, i.e. the way the CPU talks to the other stuff
2124 inside your box. Other bus systems are PCI, EISA, MicroChannel
2125 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2126 newer boards don't support it. If you have ISA, say Y, otherwise N.
2132 The Extended Industry Standard Architecture (EISA) bus was
2133 developed as an open alternative to the IBM MicroChannel bus.
2135 The EISA bus provided some of the features of the IBM MicroChannel
2136 bus while maintaining backward compatibility with cards made for
2137 the older ISA bus. The EISA bus saw limited use between 1988 and
2138 1995 when it was made obsolete by the PCI bus.
2140 Say Y here if you are building a kernel for an EISA-based machine.
2144 source "drivers/eisa/Kconfig"
2147 tristate "NatSemi SCx200 support"
2149 This provides basic support for National Semiconductor's
2150 (now AMD's) Geode processors. The driver probes for the
2151 PCI-IDs of several on-chip devices, so its a good dependency
2152 for other scx200_* drivers.
2154 If compiled as a module, the driver is named scx200.
2156 config SCx200HR_TIMER
2157 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2161 This driver provides a clocksource built upon the on-chip
2162 27MHz high-resolution timer. Its also a workaround for
2163 NSC Geode SC-1100's buggy TSC, which loses time when the
2164 processor goes idle (as is done by the scheduler). The
2165 other workaround is idle=poll boot option.
2168 bool "One Laptop Per Child support"
2175 Add support for detecting the unique features of the OLPC
2179 bool "OLPC XO-1 Power Management"
2180 depends on OLPC && MFD_CS5535 && PM_SLEEP
2183 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2186 bool "OLPC XO-1 Real Time Clock"
2187 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2189 Add support for the XO-1 real time clock, which can be used as a
2190 programmable wakeup source.
2193 bool "OLPC XO-1 SCI extras"
2194 depends on OLPC && OLPC_XO1_PM
2200 Add support for SCI-based features of the OLPC XO-1 laptop:
2201 - EC-driven system wakeups
2205 - AC adapter status updates
2206 - Battery status updates
2208 config OLPC_XO15_SCI
2209 bool "OLPC XO-1.5 SCI extras"
2210 depends on OLPC && ACPI
2213 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2214 - EC-driven system wakeups
2215 - AC adapter status updates
2216 - Battery status updates
2219 bool "PCEngines ALIX System Support (LED setup)"
2222 This option enables system support for the PCEngines ALIX.
2223 At present this just sets up LEDs for GPIO control on
2224 ALIX2/3/6 boards. However, other system specific setup should
2227 Note: You must still enable the drivers for GPIO and LED support
2228 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2230 Note: You have to set alix.force=1 for boards with Award BIOS.
2233 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2236 This option enables system support for the Soekris Engineering net5501.
2239 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2243 This option enables system support for the Traverse Technologies GEOS.
2246 bool "Technologic Systems TS-5500 platform support"
2248 select CHECK_SIGNATURE
2252 This option enables system support for the Technologic Systems TS-5500.
2258 depends on CPU_SUP_AMD && PCI
2260 source "drivers/pcmcia/Kconfig"
2262 source "drivers/pci/hotplug/Kconfig"
2265 tristate "RapidIO support"
2269 If enabled this option will include drivers and the core
2270 infrastructure code to support RapidIO interconnect devices.
2272 source "drivers/rapidio/Kconfig"
2277 menu "Executable file formats / Emulations"
2279 source "fs/Kconfig.binfmt"
2281 config IA32_EMULATION
2282 bool "IA32 Emulation"
2285 select COMPAT_BINFMT_ELF
2288 Include code to run legacy 32-bit programs under a
2289 64-bit kernel. You should likely turn this on, unless you're
2290 100% sure that you don't have any 32-bit programs left.
2293 tristate "IA32 a.out support"
2294 depends on IA32_EMULATION
2296 Support old a.out binaries in the 32bit emulation.
2299 bool "x32 ABI for 64-bit mode"
2300 depends on X86_64 && IA32_EMULATION
2302 Include code to run binaries for the x32 native 32-bit ABI
2303 for 64-bit processors. An x32 process gets access to the
2304 full 64-bit register file and wide data path while leaving
2305 pointers at 32 bits for smaller memory footprint.
2307 You will need a recent binutils (2.22 or later) with
2308 elf32_x86_64 support enabled to compile a kernel with this
2313 depends on IA32_EMULATION || X86_X32
2314 select ARCH_WANT_OLD_COMPAT_IPC
2317 config COMPAT_FOR_U64_ALIGNMENT
2320 config SYSVIPC_COMPAT
2332 config HAVE_ATOMIC_IOMAP
2336 config HAVE_TEXT_POKE_SMP
2338 select STOP_MACHINE if SMP
2340 config X86_DEV_DMA_OPS
2342 depends on X86_64 || STA2X11
2344 config X86_DMA_REMAP
2348 source "net/Kconfig"
2350 source "drivers/Kconfig"
2352 source "drivers/firmware/Kconfig"
2356 source "arch/x86/Kconfig.debug"
2358 source "security/Kconfig"
2360 source "crypto/Kconfig"
2362 source "arch/x86/kvm/Kconfig"
2364 source "lib/Kconfig"
projects / platform / adaptation / renesas_rcar / renesas_kernel.git / blob