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_HAS_DEBUG_STRICT_USER_COPY_CHECKS
25 select ARCH_MIGHT_HAVE_PC_PARPORT
26 select HAVE_AOUT if X86_32
27 select HAVE_UNSTABLE_SCHED_CLOCK
28 select ARCH_SUPPORTS_NUMA_BALANCING
29 select ARCH_SUPPORTS_INT128 if X86_64
30 select ARCH_WANTS_PROT_NUMA_PROT_NONE
33 select HAVE_PCSPKR_PLATFORM
34 select HAVE_PERF_EVENTS
35 select HAVE_IOREMAP_PROT
38 select HAVE_MEMBLOCK_NODE_MAP
39 select ARCH_DISCARD_MEMBLOCK
40 select ARCH_WANT_OPTIONAL_GPIOLIB
41 select ARCH_WANT_FRAME_POINTERS
43 select HAVE_DMA_CONTIGUOUS if !SWIOTLB
44 select HAVE_KRETPROBES
46 select HAVE_KPROBES_ON_FTRACE
47 select HAVE_FTRACE_MCOUNT_RECORD
48 select HAVE_FENTRY if X86_64
49 select HAVE_C_RECORDMCOUNT
50 select HAVE_DYNAMIC_FTRACE
51 select HAVE_DYNAMIC_FTRACE_WITH_REGS
52 select HAVE_FUNCTION_TRACER
53 select HAVE_FUNCTION_GRAPH_TRACER
54 select HAVE_FUNCTION_GRAPH_FP_TEST
55 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
56 select HAVE_SYSCALL_TRACEPOINTS
57 select SYSCTL_EXCEPTION_TRACE
60 select HAVE_ARCH_TRACEHOOK
61 select HAVE_GENERIC_DMA_COHERENT if X86_32
62 select HAVE_EFFICIENT_UNALIGNED_ACCESS
63 select USER_STACKTRACE_SUPPORT
64 select HAVE_REGS_AND_STACK_ACCESS_API
65 select HAVE_DMA_API_DEBUG
66 select HAVE_KERNEL_GZIP
67 select HAVE_KERNEL_BZIP2
68 select HAVE_KERNEL_LZMA
70 select HAVE_KERNEL_LZO
71 select HAVE_KERNEL_LZ4
72 select HAVE_HW_BREAKPOINT
73 select HAVE_MIXED_BREAKPOINTS_REGS
75 select HAVE_PERF_EVENTS_NMI
77 select HAVE_PERF_USER_STACK_DUMP
78 select HAVE_DEBUG_KMEMLEAK
80 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
81 select HAVE_CMPXCHG_LOCAL
82 select HAVE_CMPXCHG_DOUBLE
83 select HAVE_ARCH_KMEMCHECK
84 select HAVE_USER_RETURN_NOTIFIER
85 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
86 select HAVE_ARCH_JUMP_LABEL
87 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
89 select GENERIC_FIND_FIRST_BIT
90 select GENERIC_IRQ_PROBE
91 select GENERIC_PENDING_IRQ if SMP
92 select GENERIC_IRQ_SHOW
93 select GENERIC_CLOCKEVENTS_MIN_ADJUST
94 select IRQ_FORCED_THREADING
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
127 select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
128 select HAVE_CC_STACKPROTECTOR
130 config INSTRUCTION_DECODER
132 depends on KPROBES || PERF_EVENTS || UPROBES
136 default "elf32-i386" if X86_32
137 default "elf64-x86-64" if X86_64
139 config ARCH_DEFCONFIG
141 default "arch/x86/configs/i386_defconfig" if X86_32
142 default "arch/x86/configs/x86_64_defconfig" if X86_64
144 config LOCKDEP_SUPPORT
147 config STACKTRACE_SUPPORT
150 config HAVE_LATENCYTOP_SUPPORT
159 config NEED_DMA_MAP_STATE
161 depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG
163 config NEED_SG_DMA_LENGTH
166 config GENERIC_ISA_DMA
168 depends on ISA_DMA_API
173 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
175 config GENERIC_BUG_RELATIVE_POINTERS
178 config GENERIC_HWEIGHT
181 config ARCH_MAY_HAVE_PC_FDC
183 depends on ISA_DMA_API
185 config RWSEM_XCHGADD_ALGORITHM
188 config GENERIC_CALIBRATE_DELAY
191 config ARCH_HAS_CPU_RELAX
194 config ARCH_HAS_CACHE_LINE_SIZE
197 config ARCH_HAS_CPU_AUTOPROBE
200 config HAVE_SETUP_PER_CPU_AREA
203 config NEED_PER_CPU_EMBED_FIRST_CHUNK
206 config NEED_PER_CPU_PAGE_FIRST_CHUNK
209 config ARCH_HIBERNATION_POSSIBLE
212 config ARCH_SUSPEND_POSSIBLE
215 config ARCH_WANT_HUGE_PMD_SHARE
218 config ARCH_WANT_GENERAL_HUGETLB
229 config ARCH_SUPPORTS_OPTIMIZED_INLINING
232 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
235 config HAVE_INTEL_TXT
237 depends on INTEL_IOMMU && ACPI
241 depends on X86_32 && SMP
245 depends on X86_64 && SMP
251 config X86_32_LAZY_GS
253 depends on X86_32 && !CC_STACKPROTECTOR
255 config ARCH_HWEIGHT_CFLAGS
257 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
258 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
260 config ARCH_SUPPORTS_UPROBES
263 source "init/Kconfig"
264 source "kernel/Kconfig.freezer"
266 menu "Processor type and features"
269 bool "DMA memory allocation support" if EXPERT
272 DMA memory allocation support allows devices with less than 32-bit
273 addressing to allocate within the first 16MB of address space.
274 Disable if no such devices will be used.
279 bool "Symmetric multi-processing support"
281 This enables support for systems with more than one CPU. If you have
282 a system with only one CPU, like most personal computers, say N. If
283 you have a system with more than one CPU, say Y.
285 If you say N here, the kernel will run on single and multiprocessor
286 machines, but will use only one CPU of a multiprocessor machine. If
287 you say Y here, the kernel will run on many, but not all,
288 singleprocessor machines. On a singleprocessor machine, the kernel
289 will run faster if you say N here.
291 Note that if you say Y here and choose architecture "586" or
292 "Pentium" under "Processor family", the kernel will not work on 486
293 architectures. Similarly, multiprocessor kernels for the "PPro"
294 architecture may not work on all Pentium based boards.
296 People using multiprocessor machines who say Y here should also say
297 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
298 Management" code will be disabled if you say Y here.
300 See also <file:Documentation/x86/i386/IO-APIC.txt>,
301 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
302 <http://www.tldp.org/docs.html#howto>.
304 If you don't know what to do here, say N.
307 bool "Support x2apic"
308 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
310 This enables x2apic support on CPUs that have this feature.
312 This allows 32-bit apic IDs (so it can support very large systems),
313 and accesses the local apic via MSRs not via mmio.
315 If you don't know what to do here, say N.
318 bool "Enable MPS table" if ACPI || SFI
320 depends on X86_LOCAL_APIC
322 For old smp systems that do not have proper acpi support. Newer systems
323 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
326 bool "Support for big SMP systems with more than 8 CPUs"
327 depends on X86_32 && SMP
329 This option is needed for the systems that have more than 8 CPUs
333 depends on X86_GOLDFISH
336 config X86_EXTENDED_PLATFORM
337 bool "Support for extended (non-PC) x86 platforms"
340 If you disable this option then the kernel will only support
341 standard PC platforms. (which covers the vast majority of
344 If you enable this option then you'll be able to select support
345 for the following (non-PC) 32 bit x86 platforms:
346 Goldfish (Android emulator)
350 SGI 320/540 (Visual Workstation)
351 STA2X11-based (e.g. Northville)
352 Summit/EXA (IBM x440)
353 Unisys ES7000 IA32 series
354 Moorestown MID devices
356 If you have one of these systems, or if you want to build a
357 generic distribution kernel, say Y here - otherwise say N.
361 config X86_EXTENDED_PLATFORM
362 bool "Support for extended (non-PC) x86 platforms"
365 If you disable this option then the kernel will only support
366 standard PC platforms. (which covers the vast majority of
369 If you enable this option then you'll be able to select support
370 for the following (non-PC) 64 bit x86 platforms:
375 If you have one of these systems, or if you want to build a
376 generic distribution kernel, say Y here - otherwise say N.
378 # This is an alphabetically sorted list of 64 bit extended platforms
379 # Please maintain the alphabetic order if and when there are additions
381 bool "Numascale NumaChip"
383 depends on X86_EXTENDED_PLATFORM
386 depends on X86_X2APIC
387 depends on PCI_MMCONFIG
389 Adds support for Numascale NumaChip large-SMP systems. Needed to
390 enable more than ~168 cores.
391 If you don't have one of these, you should say N here.
395 select HYPERVISOR_GUEST
397 depends on X86_64 && PCI
398 depends on X86_EXTENDED_PLATFORM
401 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
402 supposed to run on these EM64T-based machines. Only choose this option
403 if you have one of these machines.
406 bool "SGI Ultraviolet"
408 depends on X86_EXTENDED_PLATFORM
410 depends on X86_X2APIC
412 This option is needed in order to support SGI Ultraviolet systems.
413 If you don't have one of these, you should say N here.
415 # Following is an alphabetically sorted list of 32 bit extended platforms
416 # Please maintain the alphabetic order if and when there are additions
419 bool "Goldfish (Virtual Platform)"
421 depends on X86_EXTENDED_PLATFORM
423 Enable support for the Goldfish virtual platform used primarily
424 for Android development. Unless you are building for the Android
425 Goldfish emulator say N here.
428 bool "CE4100 TV platform"
430 depends on PCI_GODIRECT
432 depends on X86_EXTENDED_PLATFORM
433 select X86_REBOOTFIXUPS
435 select OF_EARLY_FLATTREE
438 Select for the Intel CE media processor (CE4100) SOC.
439 This option compiles in support for the CE4100 SOC for settop
440 boxes and media devices.
443 bool "Intel MID platform support"
445 depends on X86_EXTENDED_PLATFORM
448 depends on X86_IO_APIC
454 select MFD_INTEL_MSIC
456 Select to build a kernel capable of supporting Intel MID (Mobile
457 Internet Device) platform systems which do not have the PCI legacy
458 interfaces. If you are building for a PC class system say N here.
460 Intel MID platforms are based on an Intel processor and chipset which
461 consume less power than most of the x86 derivatives.
463 config X86_INTEL_LPSS
464 bool "Intel Low Power Subsystem Support"
469 Select to build support for Intel Low Power Subsystem such as
470 found on Intel Lynxpoint PCH. Selecting this option enables
471 things like clock tree (common clock framework) and pincontrol
472 which are needed by the LPSS peripheral drivers.
475 bool "RDC R-321x SoC"
477 depends on X86_EXTENDED_PLATFORM
479 select X86_REBOOTFIXUPS
481 This option is needed for RDC R-321x system-on-chip, also known
483 If you don't have one of these chips, you should say N here.
485 config X86_32_NON_STANDARD
486 bool "Support non-standard 32-bit SMP architectures"
487 depends on X86_32 && SMP
488 depends on X86_EXTENDED_PLATFORM
490 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
491 STA2X11, default subarchitectures. It is intended for a generic
492 binary kernel. If you select them all, kernel will probe it
493 one by one and will fallback to default.
495 # Alphabetically sorted list of Non standard 32 bit platforms
498 bool "NUMAQ (IBM/Sequent)"
499 depends on X86_32_NON_STANDARD
504 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
505 NUMA multiquad box. This changes the way that processors are
506 bootstrapped, and uses Clustered Logical APIC addressing mode instead
507 of Flat Logical. You will need a new lynxer.elf file to flash your
508 firmware with - send email to <Martin.Bligh@us.ibm.com>.
510 config X86_SUPPORTS_MEMORY_FAILURE
512 # MCE code calls memory_failure():
514 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
515 depends on !X86_NUMAQ
516 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
517 depends on X86_64 || !SPARSEMEM
518 select ARCH_SUPPORTS_MEMORY_FAILURE
521 bool "SGI 320/540 (Visual Workstation)"
522 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
523 depends on X86_32_NON_STANDARD
525 The SGI Visual Workstation series is an IA32-based workstation
526 based on SGI systems chips with some legacy PC hardware attached.
528 Say Y here to create a kernel to run on the SGI 320 or 540.
530 A kernel compiled for the Visual Workstation will run on general
531 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
534 bool "STA2X11 Companion Chip Support"
535 depends on X86_32_NON_STANDARD && PCI
536 select X86_DEV_DMA_OPS
540 select ARCH_REQUIRE_GPIOLIB
543 This adds support for boards based on the STA2X11 IO-Hub,
544 a.k.a. "ConneXt". The chip is used in place of the standard
545 PC chipset, so all "standard" peripherals are missing. If this
546 option is selected the kernel will still be able to boot on
547 standard PC machines.
550 bool "Summit/EXA (IBM x440)"
551 depends on X86_32_NON_STANDARD
553 This option is needed for IBM systems that use the Summit/EXA chipset.
554 In particular, it is needed for the x440.
557 bool "Unisys ES7000 IA32 series"
558 depends on X86_32_NON_STANDARD && X86_BIGSMP
560 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
561 supposed to run on an IA32-based Unisys ES7000 system.
564 tristate "Eurobraille/Iris poweroff module"
567 The Iris machines from EuroBraille do not have APM or ACPI support
568 to shut themselves down properly. A special I/O sequence is
569 needed to do so, which is what this module does at
572 This is only for Iris machines from EuroBraille.
576 config SCHED_OMIT_FRAME_POINTER
578 prompt "Single-depth WCHAN output"
581 Calculate simpler /proc/<PID>/wchan values. If this option
582 is disabled then wchan values will recurse back to the
583 caller function. This provides more accurate wchan values,
584 at the expense of slightly more scheduling overhead.
586 If in doubt, say "Y".
588 menuconfig HYPERVISOR_GUEST
589 bool "Linux guest support"
591 Say Y here to enable options for running Linux under various hyper-
592 visors. This option enables basic hypervisor detection and platform
595 If you say N, all options in this submenu will be skipped and
596 disabled, and Linux guest support won't be built in.
601 bool "Enable paravirtualization code"
603 This changes the kernel so it can modify itself when it is run
604 under a hypervisor, potentially improving performance significantly
605 over full virtualization. However, when run without a hypervisor
606 the kernel is theoretically slower and slightly larger.
608 config PARAVIRT_DEBUG
609 bool "paravirt-ops debugging"
610 depends on PARAVIRT && DEBUG_KERNEL
612 Enable to debug paravirt_ops internals. Specifically, BUG if
613 a paravirt_op is missing when it is called.
615 config PARAVIRT_SPINLOCKS
616 bool "Paravirtualization layer for spinlocks"
617 depends on PARAVIRT && SMP
618 select UNINLINE_SPIN_UNLOCK
620 Paravirtualized spinlocks allow a pvops backend to replace the
621 spinlock implementation with something virtualization-friendly
622 (for example, block the virtual CPU rather than spinning).
624 It has a minimal impact on native kernels and gives a nice performance
625 benefit on paravirtualized KVM / Xen kernels.
627 If you are unsure how to answer this question, answer Y.
629 source "arch/x86/xen/Kconfig"
632 bool "KVM Guest support (including kvmclock)"
634 select PARAVIRT_CLOCK
637 This option enables various optimizations for running under the KVM
638 hypervisor. It includes a paravirtualized clock, so that instead
639 of relying on a PIT (or probably other) emulation by the
640 underlying device model, the host provides the guest with
641 timing infrastructure such as time of day, and system time
644 bool "Enable debug information for KVM Guests in debugfs"
645 depends on KVM_GUEST && DEBUG_FS
648 This option enables collection of various statistics for KVM guest.
649 Statistics are displayed in debugfs filesystem. Enabling this option
650 may incur significant overhead.
652 source "arch/x86/lguest/Kconfig"
654 config PARAVIRT_TIME_ACCOUNTING
655 bool "Paravirtual steal time accounting"
659 Select this option to enable fine granularity task steal time
660 accounting. Time spent executing other tasks in parallel with
661 the current vCPU is discounted from the vCPU power. To account for
662 that, there can be a small performance impact.
664 If in doubt, say N here.
666 config PARAVIRT_CLOCK
669 endif #HYPERVISOR_GUEST
677 This option adds a kernel parameter 'memtest', which allows memtest
679 memtest=0, mean disabled; -- default
680 memtest=1, mean do 1 test pattern;
682 memtest=4, mean do 4 test patterns.
683 If you are unsure how to answer this question, answer N.
685 config X86_SUMMIT_NUMA
687 depends on X86_32 && NUMA && X86_32_NON_STANDARD
689 config X86_CYCLONE_TIMER
691 depends on X86_SUMMIT
693 source "arch/x86/Kconfig.cpu"
697 prompt "HPET Timer Support" if X86_32
699 Use the IA-PC HPET (High Precision Event Timer) to manage
700 time in preference to the PIT and RTC, if a HPET is
702 HPET is the next generation timer replacing legacy 8254s.
703 The HPET provides a stable time base on SMP
704 systems, unlike the TSC, but it is more expensive to access,
705 as it is off-chip. You can find the HPET spec at
706 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
708 You can safely choose Y here. However, HPET will only be
709 activated if the platform and the BIOS support this feature.
710 Otherwise the 8254 will be used for timing services.
712 Choose N to continue using the legacy 8254 timer.
714 config HPET_EMULATE_RTC
716 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
719 def_bool y if X86_INTEL_MID
720 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
722 depends on X86_INTEL_MID && SFI
724 APB timer is the replacement for 8254, HPET on X86 MID platforms.
725 The APBT provides a stable time base on SMP
726 systems, unlike the TSC, but it is more expensive to access,
727 as it is off-chip. APB timers are always running regardless of CPU
728 C states, they are used as per CPU clockevent device when possible.
730 # Mark as expert because too many people got it wrong.
731 # The code disables itself when not needed.
734 bool "Enable DMI scanning" if EXPERT
736 Enabled scanning of DMI to identify machine quirks. Say Y
737 here unless you have verified that your setup is not
738 affected by entries in the DMI blacklist. Required by PNP
742 bool "Old AMD GART IOMMU support"
744 depends on X86_64 && PCI && AMD_NB
746 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
747 GART based hardware IOMMUs.
749 The GART supports full DMA access for devices with 32-bit access
750 limitations, on systems with more than 3 GB. This is usually needed
751 for USB, sound, many IDE/SATA chipsets and some other devices.
753 Newer systems typically have a modern AMD IOMMU, supported via
754 the CONFIG_AMD_IOMMU=y config option.
756 In normal configurations this driver is only active when needed:
757 there's more than 3 GB of memory and the system contains a
758 32-bit limited device.
763 bool "IBM Calgary IOMMU support"
765 depends on X86_64 && PCI
767 Support for hardware IOMMUs in IBM's xSeries x366 and x460
768 systems. Needed to run systems with more than 3GB of memory
769 properly with 32-bit PCI devices that do not support DAC
770 (Double Address Cycle). Calgary also supports bus level
771 isolation, where all DMAs pass through the IOMMU. This
772 prevents them from going anywhere except their intended
773 destination. This catches hard-to-find kernel bugs and
774 mis-behaving drivers and devices that do not use the DMA-API
775 properly to set up their DMA buffers. The IOMMU can be
776 turned off at boot time with the iommu=off parameter.
777 Normally the kernel will make the right choice by itself.
780 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
782 prompt "Should Calgary be enabled by default?"
783 depends on CALGARY_IOMMU
785 Should Calgary be enabled by default? if you choose 'y', Calgary
786 will be used (if it exists). If you choose 'n', Calgary will not be
787 used even if it exists. If you choose 'n' and would like to use
788 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
791 # need this always selected by IOMMU for the VIA workaround
795 Support for software bounce buffers used on x86-64 systems
796 which don't have a hardware IOMMU. Using this PCI devices
797 which can only access 32-bits of memory can be used on systems
798 with more than 3 GB of memory.
803 depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
806 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
807 depends on X86_64 && SMP && DEBUG_KERNEL
808 select CPUMASK_OFFSTACK
810 Enable maximum number of CPUS and NUMA Nodes for this architecture.
814 int "Maximum number of CPUs" if SMP && !MAXSMP
815 range 2 8 if SMP && X86_32 && !X86_BIGSMP
816 range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK
817 range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
819 default "8192" if MAXSMP
820 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
823 This allows you to specify the maximum number of CPUs which this
824 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
825 supported value is 4096, otherwise the maximum value is 512. The
826 minimum value which makes sense is 2.
828 This is purely to save memory - each supported CPU adds
829 approximately eight kilobytes to the kernel image.
832 bool "SMT (Hyperthreading) scheduler support"
835 SMT scheduler support improves the CPU scheduler's decision making
836 when dealing with Intel Pentium 4 chips with HyperThreading at a
837 cost of slightly increased overhead in some places. If unsure say
842 prompt "Multi-core scheduler support"
845 Multi-core scheduler support improves the CPU scheduler's decision
846 making when dealing with multi-core CPU chips at a cost of slightly
847 increased overhead in some places. If unsure say N here.
849 source "kernel/Kconfig.preempt"
852 bool "Local APIC support on uniprocessors"
853 depends on X86_32 && !SMP && !X86_32_NON_STANDARD && !PCI_MSI
855 A local APIC (Advanced Programmable Interrupt Controller) is an
856 integrated interrupt controller in the CPU. If you have a single-CPU
857 system which has a processor with a local APIC, you can say Y here to
858 enable and use it. If you say Y here even though your machine doesn't
859 have a local APIC, then the kernel will still run with no slowdown at
860 all. The local APIC supports CPU-generated self-interrupts (timer,
861 performance counters), and the NMI watchdog which detects hard
865 bool "IO-APIC support on uniprocessors"
866 depends on X86_UP_APIC
868 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
869 SMP-capable replacement for PC-style interrupt controllers. Most
870 SMP systems and many recent uniprocessor systems have one.
872 If you have a single-CPU system with an IO-APIC, you can say Y here
873 to use it. If you say Y here even though your machine doesn't have
874 an IO-APIC, then the kernel will still run with no slowdown at all.
876 config X86_LOCAL_APIC
878 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
882 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC || PCI_MSI
884 config X86_VISWS_APIC
886 depends on X86_32 && X86_VISWS
888 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
889 bool "Reroute for broken boot IRQs"
890 depends on X86_IO_APIC
892 This option enables a workaround that fixes a source of
893 spurious interrupts. This is recommended when threaded
894 interrupt handling is used on systems where the generation of
895 superfluous "boot interrupts" cannot be disabled.
897 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
898 entry in the chipset's IO-APIC is masked (as, e.g. the RT
899 kernel does during interrupt handling). On chipsets where this
900 boot IRQ generation cannot be disabled, this workaround keeps
901 the original IRQ line masked so that only the equivalent "boot
902 IRQ" is delivered to the CPUs. The workaround also tells the
903 kernel to set up the IRQ handler on the boot IRQ line. In this
904 way only one interrupt is delivered to the kernel. Otherwise
905 the spurious second interrupt may cause the kernel to bring
906 down (vital) interrupt lines.
908 Only affects "broken" chipsets. Interrupt sharing may be
909 increased on these systems.
912 bool "Machine Check / overheating reporting"
915 Machine Check support allows the processor to notify the
916 kernel if it detects a problem (e.g. overheating, data corruption).
917 The action the kernel takes depends on the severity of the problem,
918 ranging from warning messages to halting the machine.
922 prompt "Intel MCE features"
923 depends on X86_MCE && X86_LOCAL_APIC
925 Additional support for intel specific MCE features such as
930 prompt "AMD MCE features"
931 depends on X86_MCE && X86_LOCAL_APIC
933 Additional support for AMD specific MCE features such as
934 the DRAM Error Threshold.
936 config X86_ANCIENT_MCE
937 bool "Support for old Pentium 5 / WinChip machine checks"
938 depends on X86_32 && X86_MCE
940 Include support for machine check handling on old Pentium 5 or WinChip
941 systems. These typically need to be enabled explicitely on the command
944 config X86_MCE_THRESHOLD
945 depends on X86_MCE_AMD || X86_MCE_INTEL
948 config X86_MCE_INJECT
950 tristate "Machine check injector support"
952 Provide support for injecting machine checks for testing purposes.
953 If you don't know what a machine check is and you don't do kernel
954 QA it is safe to say n.
956 config X86_THERMAL_VECTOR
958 depends on X86_MCE_INTEL
961 bool "Enable VM86 support" if EXPERT
965 This option is required by programs like DOSEMU to run 16-bit legacy
966 code on X86 processors. It also may be needed by software like
967 XFree86 to initialize some video cards via BIOS. Disabling this
968 option saves about 6k.
971 tristate "Toshiba Laptop support"
974 This adds a driver to safely access the System Management Mode of
975 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
976 not work on models with a Phoenix BIOS. The System Management Mode
977 is used to set the BIOS and power saving options on Toshiba portables.
979 For information on utilities to make use of this driver see the
980 Toshiba Linux utilities web site at:
981 <http://www.buzzard.org.uk/toshiba/>.
983 Say Y if you intend to run this kernel on a Toshiba portable.
987 tristate "Dell laptop support"
990 This adds a driver to safely access the System Management Mode
991 of the CPU on the Dell Inspiron 8000. The System Management Mode
992 is used to read cpu temperature and cooling fan status and to
993 control the fans on the I8K portables.
995 This driver has been tested only on the Inspiron 8000 but it may
996 also work with other Dell laptops. You can force loading on other
997 models by passing the parameter `force=1' to the module. Use at
1000 For information on utilities to make use of this driver see the
1001 I8K Linux utilities web site at:
1002 <http://people.debian.org/~dz/i8k/>
1004 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
1007 config X86_REBOOTFIXUPS
1008 bool "Enable X86 board specific fixups for reboot"
1011 This enables chipset and/or board specific fixups to be done
1012 in order to get reboot to work correctly. This is only needed on
1013 some combinations of hardware and BIOS. The symptom, for which
1014 this config is intended, is when reboot ends with a stalled/hung
1017 Currently, the only fixup is for the Geode machines using
1018 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1020 Say Y if you want to enable the fixup. Currently, it's safe to
1021 enable this option even if you don't need it.
1025 tristate "CPU microcode loading support"
1026 depends on CPU_SUP_AMD || CPU_SUP_INTEL
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
1348 bool "Enable sysfs memory/probe interface"
1349 depends on X86_64 && MEMORY_HOTPLUG
1351 This option enables a sysfs memory/probe interface for testing.
1352 See Documentation/memory-hotplug.txt for more information.
1353 If you are unsure how to answer this question, answer N.
1355 config ARCH_PROC_KCORE_TEXT
1357 depends on X86_64 && PROC_KCORE
1359 config ILLEGAL_POINTER_VALUE
1362 default 0xdead000000000000 if X86_64
1367 bool "Allocate 3rd-level pagetables from highmem"
1370 The VM uses one page table entry for each page of physical memory.
1371 For systems with a lot of RAM, this can be wasteful of precious
1372 low memory. Setting this option will put user-space page table
1373 entries in high memory.
1375 config X86_CHECK_BIOS_CORRUPTION
1376 bool "Check for low memory corruption"
1378 Periodically check for memory corruption in low memory, which
1379 is suspected to be caused by BIOS. Even when enabled in the
1380 configuration, it is disabled at runtime. Enable it by
1381 setting "memory_corruption_check=1" on the kernel command
1382 line. By default it scans the low 64k of memory every 60
1383 seconds; see the memory_corruption_check_size and
1384 memory_corruption_check_period parameters in
1385 Documentation/kernel-parameters.txt to adjust this.
1387 When enabled with the default parameters, this option has
1388 almost no overhead, as it reserves a relatively small amount
1389 of memory and scans it infrequently. It both detects corruption
1390 and prevents it from affecting the running system.
1392 It is, however, intended as a diagnostic tool; if repeatable
1393 BIOS-originated corruption always affects the same memory,
1394 you can use memmap= to prevent the kernel from using that
1397 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1398 bool "Set the default setting of memory_corruption_check"
1399 depends on X86_CHECK_BIOS_CORRUPTION
1402 Set whether the default state of memory_corruption_check is
1405 config X86_RESERVE_LOW
1406 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1410 Specify the amount of low memory to reserve for the BIOS.
1412 The first page contains BIOS data structures that the kernel
1413 must not use, so that page must always be reserved.
1415 By default we reserve the first 64K of physical RAM, as a
1416 number of BIOSes are known to corrupt that memory range
1417 during events such as suspend/resume or monitor cable
1418 insertion, so it must not be used by the kernel.
1420 You can set this to 4 if you are absolutely sure that you
1421 trust the BIOS to get all its memory reservations and usages
1422 right. If you know your BIOS have problems beyond the
1423 default 64K area, you can set this to 640 to avoid using the
1424 entire low memory range.
1426 If you have doubts about the BIOS (e.g. suspend/resume does
1427 not work or there's kernel crashes after certain hardware
1428 hotplug events) then you might want to enable
1429 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1430 typical corruption patterns.
1432 Leave this to the default value of 64 if you are unsure.
1434 config MATH_EMULATION
1436 prompt "Math emulation" if X86_32
1438 Linux can emulate a math coprocessor (used for floating point
1439 operations) if you don't have one. 486DX and Pentium processors have
1440 a math coprocessor built in, 486SX and 386 do not, unless you added
1441 a 487DX or 387, respectively. (The messages during boot time can
1442 give you some hints here ["man dmesg"].) Everyone needs either a
1443 coprocessor or this emulation.
1445 If you don't have a math coprocessor, you need to say Y here; if you
1446 say Y here even though you have a coprocessor, the coprocessor will
1447 be used nevertheless. (This behavior can be changed with the kernel
1448 command line option "no387", which comes handy if your coprocessor
1449 is broken. Try "man bootparam" or see the documentation of your boot
1450 loader (lilo or loadlin) about how to pass options to the kernel at
1451 boot time.) This means that it is a good idea to say Y here if you
1452 intend to use this kernel on different machines.
1454 More information about the internals of the Linux math coprocessor
1455 emulation can be found in <file:arch/x86/math-emu/README>.
1457 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1458 kernel, it won't hurt.
1462 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1464 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1465 the Memory Type Range Registers (MTRRs) may be used to control
1466 processor access to memory ranges. This is most useful if you have
1467 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1468 allows bus write transfers to be combined into a larger transfer
1469 before bursting over the PCI/AGP bus. This can increase performance
1470 of image write operations 2.5 times or more. Saying Y here creates a
1471 /proc/mtrr file which may be used to manipulate your processor's
1472 MTRRs. Typically the X server should use this.
1474 This code has a reasonably generic interface so that similar
1475 control registers on other processors can be easily supported
1478 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1479 Registers (ARRs) which provide a similar functionality to MTRRs. For
1480 these, the ARRs are used to emulate the MTRRs.
1481 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1482 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1483 write-combining. All of these processors are supported by this code
1484 and it makes sense to say Y here if you have one of them.
1486 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1487 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1488 can lead to all sorts of problems, so it's good to say Y here.
1490 You can safely say Y even if your machine doesn't have MTRRs, you'll
1491 just add about 9 KB to your kernel.
1493 See <file:Documentation/x86/mtrr.txt> for more information.
1495 config MTRR_SANITIZER
1497 prompt "MTRR cleanup support"
1500 Convert MTRR layout from continuous to discrete, so X drivers can
1501 add writeback entries.
1503 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1504 The largest mtrr entry size for a continuous block can be set with
1509 config MTRR_SANITIZER_ENABLE_DEFAULT
1510 int "MTRR cleanup enable value (0-1)"
1513 depends on MTRR_SANITIZER
1515 Enable mtrr cleanup default value
1517 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1518 int "MTRR cleanup spare reg num (0-7)"
1521 depends on MTRR_SANITIZER
1523 mtrr cleanup spare entries default, it can be changed via
1524 mtrr_spare_reg_nr=N on the kernel command line.
1528 prompt "x86 PAT support" if EXPERT
1531 Use PAT attributes to setup page level cache control.
1533 PATs are the modern equivalents of MTRRs and are much more
1534 flexible than MTRRs.
1536 Say N here if you see bootup problems (boot crash, boot hang,
1537 spontaneous reboots) or a non-working video driver.
1541 config ARCH_USES_PG_UNCACHED
1547 prompt "x86 architectural random number generator" if EXPERT
1549 Enable the x86 architectural RDRAND instruction
1550 (Intel Bull Mountain technology) to generate random numbers.
1551 If supported, this is a high bandwidth, cryptographically
1552 secure hardware random number generator.
1556 prompt "Supervisor Mode Access Prevention" if EXPERT
1558 Supervisor Mode Access Prevention (SMAP) is a security
1559 feature in newer Intel processors. There is a small
1560 performance cost if this enabled and turned on; there is
1561 also a small increase in the kernel size if this is enabled.
1566 bool "EFI runtime service support"
1570 This enables the kernel to use EFI runtime services that are
1571 available (such as the EFI variable services).
1573 This option is only useful on systems that have EFI firmware.
1574 In addition, you should use the latest ELILO loader available
1575 at <http://elilo.sourceforge.net> in order to take advantage
1576 of EFI runtime services. However, even with this option, the
1577 resultant kernel should continue to boot on existing non-EFI
1581 bool "EFI stub support"
1584 This kernel feature allows a bzImage to be loaded directly
1585 by EFI firmware without the use of a bootloader.
1587 See Documentation/efi-stub.txt for more information.
1591 prompt "Enable seccomp to safely compute untrusted bytecode"
1593 This kernel feature is useful for number crunching applications
1594 that may need to compute untrusted bytecode during their
1595 execution. By using pipes or other transports made available to
1596 the process as file descriptors supporting the read/write
1597 syscalls, it's possible to isolate those applications in
1598 their own address space using seccomp. Once seccomp is
1599 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1600 and the task is only allowed to execute a few safe syscalls
1601 defined by each seccomp mode.
1603 If unsure, say Y. Only embedded should say N here.
1605 source kernel/Kconfig.hz
1608 bool "kexec system call"
1610 kexec is a system call that implements the ability to shutdown your
1611 current kernel, and to start another kernel. It is like a reboot
1612 but it is independent of the system firmware. And like a reboot
1613 you can start any kernel with it, not just Linux.
1615 The name comes from the similarity to the exec system call.
1617 It is an ongoing process to be certain the hardware in a machine
1618 is properly shutdown, so do not be surprised if this code does not
1619 initially work for you. As of this writing the exact hardware
1620 interface is strongly in flux, so no good recommendation can be
1624 bool "kernel crash dumps"
1625 depends on X86_64 || (X86_32 && HIGHMEM)
1627 Generate crash dump after being started by kexec.
1628 This should be normally only set in special crash dump kernels
1629 which are loaded in the main kernel with kexec-tools into
1630 a specially reserved region and then later executed after
1631 a crash by kdump/kexec. The crash dump kernel must be compiled
1632 to a memory address not used by the main kernel or BIOS using
1633 PHYSICAL_START, or it must be built as a relocatable image
1634 (CONFIG_RELOCATABLE=y).
1635 For more details see Documentation/kdump/kdump.txt
1639 depends on KEXEC && HIBERNATION
1641 Jump between original kernel and kexeced kernel and invoke
1642 code in physical address mode via KEXEC
1644 config PHYSICAL_START
1645 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1648 This gives the physical address where the kernel is loaded.
1650 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1651 bzImage will decompress itself to above physical address and
1652 run from there. Otherwise, bzImage will run from the address where
1653 it has been loaded by the boot loader and will ignore above physical
1656 In normal kdump cases one does not have to set/change this option
1657 as now bzImage can be compiled as a completely relocatable image
1658 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1659 address. This option is mainly useful for the folks who don't want
1660 to use a bzImage for capturing the crash dump and want to use a
1661 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1662 to be specifically compiled to run from a specific memory area
1663 (normally a reserved region) and this option comes handy.
1665 So if you are using bzImage for capturing the crash dump,
1666 leave the value here unchanged to 0x1000000 and set
1667 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1668 for capturing the crash dump change this value to start of
1669 the reserved region. In other words, it can be set based on
1670 the "X" value as specified in the "crashkernel=YM@XM"
1671 command line boot parameter passed to the panic-ed
1672 kernel. Please take a look at Documentation/kdump/kdump.txt
1673 for more details about crash dumps.
1675 Usage of bzImage for capturing the crash dump is recommended as
1676 one does not have to build two kernels. Same kernel can be used
1677 as production kernel and capture kernel. Above option should have
1678 gone away after relocatable bzImage support is introduced. But it
1679 is present because there are users out there who continue to use
1680 vmlinux for dump capture. This option should go away down the
1683 Don't change this unless you know what you are doing.
1686 bool "Build a relocatable kernel"
1689 This builds a kernel image that retains relocation information
1690 so it can be loaded someplace besides the default 1MB.
1691 The relocations tend to make the kernel binary about 10% larger,
1692 but are discarded at runtime.
1694 One use is for the kexec on panic case where the recovery kernel
1695 must live at a different physical address than the primary
1698 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1699 it has been loaded at and the compile time physical address
1700 (CONFIG_PHYSICAL_START) is ignored.
1702 # Relocation on x86-32 needs some additional build support
1703 config X86_NEED_RELOCS
1705 depends on X86_32 && RELOCATABLE
1707 config PHYSICAL_ALIGN
1708 hex "Alignment value to which kernel should be aligned"
1710 range 0x2000 0x1000000 if X86_32
1711 range 0x200000 0x1000000 if X86_64
1713 This value puts the alignment restrictions on physical address
1714 where kernel is loaded and run from. Kernel is compiled for an
1715 address which meets above alignment restriction.
1717 If bootloader loads the kernel at a non-aligned address and
1718 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1719 address aligned to above value and run from there.
1721 If bootloader loads the kernel at a non-aligned address and
1722 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1723 load address and decompress itself to the address it has been
1724 compiled for and run from there. The address for which kernel is
1725 compiled already meets above alignment restrictions. Hence the
1726 end result is that kernel runs from a physical address meeting
1727 above alignment restrictions.
1729 On 32-bit this value must be a multiple of 0x2000. On 64-bit
1730 this value must be a multiple of 0x200000.
1732 Don't change this unless you know what you are doing.
1735 bool "Support for hot-pluggable CPUs"
1738 Say Y here to allow turning CPUs off and on. CPUs can be
1739 controlled through /sys/devices/system/cpu.
1740 ( Note: power management support will enable this option
1741 automatically on SMP systems. )
1742 Say N if you want to disable CPU hotplug.
1744 config BOOTPARAM_HOTPLUG_CPU0
1745 bool "Set default setting of cpu0_hotpluggable"
1747 depends on HOTPLUG_CPU
1749 Set whether default state of cpu0_hotpluggable is on or off.
1751 Say Y here to enable CPU0 hotplug by default. If this switch
1752 is turned on, there is no need to give cpu0_hotplug kernel
1753 parameter and the CPU0 hotplug feature is enabled by default.
1755 Please note: there are two known CPU0 dependencies if you want
1756 to enable the CPU0 hotplug feature either by this switch or by
1757 cpu0_hotplug kernel parameter.
1759 First, resume from hibernate or suspend always starts from CPU0.
1760 So hibernate and suspend are prevented if CPU0 is offline.
1762 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
1763 offline if any interrupt can not migrate out of CPU0. There may
1764 be other CPU0 dependencies.
1766 Please make sure the dependencies are under your control before
1767 you enable this feature.
1769 Say N if you don't want to enable CPU0 hotplug feature by default.
1770 You still can enable the CPU0 hotplug feature at boot by kernel
1771 parameter cpu0_hotplug.
1773 config DEBUG_HOTPLUG_CPU0
1775 prompt "Debug CPU0 hotplug"
1776 depends on HOTPLUG_CPU
1778 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
1779 soon as possible and boots up userspace with CPU0 offlined. User
1780 can online CPU0 back after boot time.
1782 To debug CPU0 hotplug, you need to enable CPU0 offline/online
1783 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
1784 compilation or giving cpu0_hotplug kernel parameter at boot.
1790 prompt "Compat VDSO support"
1791 depends on X86_32 || IA32_EMULATION
1793 Map the 32-bit VDSO to the predictable old-style address too.
1795 Say N here if you are running a sufficiently recent glibc
1796 version (2.3.3 or later), to remove the high-mapped
1797 VDSO mapping and to exclusively use the randomized VDSO.
1802 bool "Built-in kernel command line"
1804 Allow for specifying boot arguments to the kernel at
1805 build time. On some systems (e.g. embedded ones), it is
1806 necessary or convenient to provide some or all of the
1807 kernel boot arguments with the kernel itself (that is,
1808 to not rely on the boot loader to provide them.)
1810 To compile command line arguments into the kernel,
1811 set this option to 'Y', then fill in the
1812 the boot arguments in CONFIG_CMDLINE.
1814 Systems with fully functional boot loaders (i.e. non-embedded)
1815 should leave this option set to 'N'.
1818 string "Built-in kernel command string"
1819 depends on CMDLINE_BOOL
1822 Enter arguments here that should be compiled into the kernel
1823 image and used at boot time. If the boot loader provides a
1824 command line at boot time, it is appended to this string to
1825 form the full kernel command line, when the system boots.
1827 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1828 change this behavior.
1830 In most cases, the command line (whether built-in or provided
1831 by the boot loader) should specify the device for the root
1834 config CMDLINE_OVERRIDE
1835 bool "Built-in command line overrides boot loader arguments"
1836 depends on CMDLINE_BOOL
1838 Set this option to 'Y' to have the kernel ignore the boot loader
1839 command line, and use ONLY the built-in command line.
1841 This is used to work around broken boot loaders. This should
1842 be set to 'N' under normal conditions.
1846 config ARCH_ENABLE_MEMORY_HOTPLUG
1848 depends on X86_64 || (X86_32 && HIGHMEM)
1850 config ARCH_ENABLE_MEMORY_HOTREMOVE
1852 depends on MEMORY_HOTPLUG
1854 config USE_PERCPU_NUMA_NODE_ID
1858 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
1860 depends on X86_64 || X86_PAE
1862 menu "Power management and ACPI options"
1864 config ARCH_HIBERNATION_HEADER
1866 depends on X86_64 && HIBERNATION
1868 source "kernel/power/Kconfig"
1870 source "drivers/acpi/Kconfig"
1872 source "drivers/sfi/Kconfig"
1879 tristate "APM (Advanced Power Management) BIOS support"
1880 depends on X86_32 && PM_SLEEP
1882 APM is a BIOS specification for saving power using several different
1883 techniques. This is mostly useful for battery powered laptops with
1884 APM compliant BIOSes. If you say Y here, the system time will be
1885 reset after a RESUME operation, the /proc/apm device will provide
1886 battery status information, and user-space programs will receive
1887 notification of APM "events" (e.g. battery status change).
1889 If you select "Y" here, you can disable actual use of the APM
1890 BIOS by passing the "apm=off" option to the kernel at boot time.
1892 Note that the APM support is almost completely disabled for
1893 machines with more than one CPU.
1895 In order to use APM, you will need supporting software. For location
1896 and more information, read <file:Documentation/power/apm-acpi.txt>
1897 and the Battery Powered Linux mini-HOWTO, available from
1898 <http://www.tldp.org/docs.html#howto>.
1900 This driver does not spin down disk drives (see the hdparm(8)
1901 manpage ("man 8 hdparm") for that), and it doesn't turn off
1902 VESA-compliant "green" monitors.
1904 This driver does not support the TI 4000M TravelMate and the ACER
1905 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1906 desktop machines also don't have compliant BIOSes, and this driver
1907 may cause those machines to panic during the boot phase.
1909 Generally, if you don't have a battery in your machine, there isn't
1910 much point in using this driver and you should say N. If you get
1911 random kernel OOPSes or reboots that don't seem to be related to
1912 anything, try disabling/enabling this option (or disabling/enabling
1915 Some other things you should try when experiencing seemingly random,
1918 1) make sure that you have enough swap space and that it is
1920 2) pass the "no-hlt" option to the kernel
1921 3) switch on floating point emulation in the kernel and pass
1922 the "no387" option to the kernel
1923 4) pass the "floppy=nodma" option to the kernel
1924 5) pass the "mem=4M" option to the kernel (thereby disabling
1925 all but the first 4 MB of RAM)
1926 6) make sure that the CPU is not over clocked.
1927 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1928 8) disable the cache from your BIOS settings
1929 9) install a fan for the video card or exchange video RAM
1930 10) install a better fan for the CPU
1931 11) exchange RAM chips
1932 12) exchange the motherboard.
1934 To compile this driver as a module, choose M here: the
1935 module will be called apm.
1939 config APM_IGNORE_USER_SUSPEND
1940 bool "Ignore USER SUSPEND"
1942 This option will ignore USER SUSPEND requests. On machines with a
1943 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1944 series notebooks, it is necessary to say Y because of a BIOS bug.
1946 config APM_DO_ENABLE
1947 bool "Enable PM at boot time"
1949 Enable APM features at boot time. From page 36 of the APM BIOS
1950 specification: "When disabled, the APM BIOS does not automatically
1951 power manage devices, enter the Standby State, enter the Suspend
1952 State, or take power saving steps in response to CPU Idle calls."
1953 This driver will make CPU Idle calls when Linux is idle (unless this
1954 feature is turned off -- see "Do CPU IDLE calls", below). This
1955 should always save battery power, but more complicated APM features
1956 will be dependent on your BIOS implementation. You may need to turn
1957 this option off if your computer hangs at boot time when using APM
1958 support, or if it beeps continuously instead of suspending. Turn
1959 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1960 T400CDT. This is off by default since most machines do fine without
1965 bool "Make CPU Idle calls when idle"
1967 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1968 On some machines, this can activate improved power savings, such as
1969 a slowed CPU clock rate, when the machine is idle. These idle calls
1970 are made after the idle loop has run for some length of time (e.g.,
1971 333 mS). On some machines, this will cause a hang at boot time or
1972 whenever the CPU becomes idle. (On machines with more than one CPU,
1973 this option does nothing.)
1975 config APM_DISPLAY_BLANK
1976 bool "Enable console blanking using APM"
1978 Enable console blanking using the APM. Some laptops can use this to
1979 turn off the LCD backlight when the screen blanker of the Linux
1980 virtual console blanks the screen. Note that this is only used by
1981 the virtual console screen blanker, and won't turn off the backlight
1982 when using the X Window system. This also doesn't have anything to
1983 do with your VESA-compliant power-saving monitor. Further, this
1984 option doesn't work for all laptops -- it might not turn off your
1985 backlight at all, or it might print a lot of errors to the console,
1986 especially if you are using gpm.
1988 config APM_ALLOW_INTS
1989 bool "Allow interrupts during APM BIOS calls"
1991 Normally we disable external interrupts while we are making calls to
1992 the APM BIOS as a measure to lessen the effects of a badly behaving
1993 BIOS implementation. The BIOS should reenable interrupts if it
1994 needs to. Unfortunately, some BIOSes do not -- especially those in
1995 many of the newer IBM Thinkpads. If you experience hangs when you
1996 suspend, try setting this to Y. Otherwise, say N.
2000 source "drivers/cpufreq/Kconfig"
2002 source "drivers/cpuidle/Kconfig"
2004 source "drivers/idle/Kconfig"
2009 menu "Bus options (PCI etc.)"
2015 Find out whether you have a PCI motherboard. PCI is the name of a
2016 bus system, i.e. the way the CPU talks to the other stuff inside
2017 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2018 VESA. If you have PCI, say Y, otherwise N.
2021 prompt "PCI access mode"
2022 depends on X86_32 && PCI
2025 On PCI systems, the BIOS can be used to detect the PCI devices and
2026 determine their configuration. However, some old PCI motherboards
2027 have BIOS bugs and may crash if this is done. Also, some embedded
2028 PCI-based systems don't have any BIOS at all. Linux can also try to
2029 detect the PCI hardware directly without using the BIOS.
2031 With this option, you can specify how Linux should detect the
2032 PCI devices. If you choose "BIOS", the BIOS will be used,
2033 if you choose "Direct", the BIOS won't be used, and if you
2034 choose "MMConfig", then PCI Express MMCONFIG will be used.
2035 If you choose "Any", the kernel will try MMCONFIG, then the
2036 direct access method and falls back to the BIOS if that doesn't
2037 work. If unsure, go with the default, which is "Any".
2042 config PCI_GOMMCONFIG
2059 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2061 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2064 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2068 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2072 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2076 depends on PCI && XEN
2084 bool "Support mmconfig PCI config space access"
2085 depends on X86_64 && PCI && ACPI
2087 config PCI_CNB20LE_QUIRK
2088 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2091 Read the PCI windows out of the CNB20LE host bridge. This allows
2092 PCI hotplug to work on systems with the CNB20LE chipset which do
2095 There's no public spec for this chipset, and this functionality
2096 is known to be incomplete.
2098 You should say N unless you know you need this.
2100 source "drivers/pci/pcie/Kconfig"
2102 source "drivers/pci/Kconfig"
2104 # x86_64 have no ISA slots, but can have ISA-style DMA.
2106 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2109 Enables ISA-style DMA support for devices requiring such controllers.
2117 Find out whether you have ISA slots on your motherboard. ISA is the
2118 name of a bus system, i.e. the way the CPU talks to the other stuff
2119 inside your box. Other bus systems are PCI, EISA, MicroChannel
2120 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2121 newer boards don't support it. If you have ISA, say Y, otherwise N.
2127 The Extended Industry Standard Architecture (EISA) bus was
2128 developed as an open alternative to the IBM MicroChannel bus.
2130 The EISA bus provided some of the features of the IBM MicroChannel
2131 bus while maintaining backward compatibility with cards made for
2132 the older ISA bus. The EISA bus saw limited use between 1988 and
2133 1995 when it was made obsolete by the PCI bus.
2135 Say Y here if you are building a kernel for an EISA-based machine.
2139 source "drivers/eisa/Kconfig"
2142 tristate "NatSemi SCx200 support"
2144 This provides basic support for National Semiconductor's
2145 (now AMD's) Geode processors. The driver probes for the
2146 PCI-IDs of several on-chip devices, so its a good dependency
2147 for other scx200_* drivers.
2149 If compiled as a module, the driver is named scx200.
2151 config SCx200HR_TIMER
2152 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2156 This driver provides a clocksource built upon the on-chip
2157 27MHz high-resolution timer. Its also a workaround for
2158 NSC Geode SC-1100's buggy TSC, which loses time when the
2159 processor goes idle (as is done by the scheduler). The
2160 other workaround is idle=poll boot option.
2163 bool "One Laptop Per Child support"
2170 Add support for detecting the unique features of the OLPC
2174 bool "OLPC XO-1 Power Management"
2175 depends on OLPC && MFD_CS5535 && PM_SLEEP
2178 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2181 bool "OLPC XO-1 Real Time Clock"
2182 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2184 Add support for the XO-1 real time clock, which can be used as a
2185 programmable wakeup source.
2188 bool "OLPC XO-1 SCI extras"
2189 depends on OLPC && OLPC_XO1_PM
2195 Add support for SCI-based features of the OLPC XO-1 laptop:
2196 - EC-driven system wakeups
2200 - AC adapter status updates
2201 - Battery status updates
2203 config OLPC_XO15_SCI
2204 bool "OLPC XO-1.5 SCI extras"
2205 depends on OLPC && ACPI
2208 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2209 - EC-driven system wakeups
2210 - AC adapter status updates
2211 - Battery status updates
2214 bool "PCEngines ALIX System Support (LED setup)"
2217 This option enables system support for the PCEngines ALIX.
2218 At present this just sets up LEDs for GPIO control on
2219 ALIX2/3/6 boards. However, other system specific setup should
2222 Note: You must still enable the drivers for GPIO and LED support
2223 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2225 Note: You have to set alix.force=1 for boards with Award BIOS.
2228 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2231 This option enables system support for the Soekris Engineering net5501.
2234 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2238 This option enables system support for the Traverse Technologies GEOS.
2241 bool "Technologic Systems TS-5500 platform support"
2243 select CHECK_SIGNATURE
2247 This option enables system support for the Technologic Systems TS-5500.
2253 depends on CPU_SUP_AMD && PCI
2255 source "drivers/pcmcia/Kconfig"
2257 source "drivers/pci/hotplug/Kconfig"
2260 tristate "RapidIO support"
2264 If enabled this option will include drivers and the core
2265 infrastructure code to support RapidIO interconnect devices.
2267 source "drivers/rapidio/Kconfig"
2270 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2272 Firmwares often provide initial graphics framebuffers so the BIOS,
2273 bootloader or kernel can show basic video-output during boot for
2274 user-guidance and debugging. Historically, x86 used the VESA BIOS
2275 Extensions and EFI-framebuffers for this, which are mostly limited
2277 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2278 framebuffers so the new generic system-framebuffer drivers can be
2279 used on x86. If the framebuffer is not compatible with the generic
2280 modes, it is adverticed as fallback platform framebuffer so legacy
2281 drivers like efifb, vesafb and uvesafb can pick it up.
2282 If this option is not selected, all system framebuffers are always
2283 marked as fallback platform framebuffers as usual.
2285 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2286 not be able to pick up generic system framebuffers if this option
2287 is selected. You are highly encouraged to enable simplefb as
2288 replacement if you select this option. simplefb can correctly deal
2289 with generic system framebuffers. But you should still keep vesafb
2290 and others enabled as fallback if a system framebuffer is
2291 incompatible with simplefb.
2298 menu "Executable file formats / Emulations"
2300 source "fs/Kconfig.binfmt"
2302 config IA32_EMULATION
2303 bool "IA32 Emulation"
2306 select COMPAT_BINFMT_ELF
2309 Include code to run legacy 32-bit programs under a
2310 64-bit kernel. You should likely turn this on, unless you're
2311 100% sure that you don't have any 32-bit programs left.
2314 tristate "IA32 a.out support"
2315 depends on IA32_EMULATION
2317 Support old a.out binaries in the 32bit emulation.
2320 bool "x32 ABI for 64-bit mode"
2321 depends on X86_64 && IA32_EMULATION
2323 Include code to run binaries for the x32 native 32-bit ABI
2324 for 64-bit processors. An x32 process gets access to the
2325 full 64-bit register file and wide data path while leaving
2326 pointers at 32 bits for smaller memory footprint.
2328 You will need a recent binutils (2.22 or later) with
2329 elf32_x86_64 support enabled to compile a kernel with this
2334 depends on IA32_EMULATION || X86_X32
2335 select ARCH_WANT_OLD_COMPAT_IPC
2338 config COMPAT_FOR_U64_ALIGNMENT
2341 config SYSVIPC_COMPAT
2353 config HAVE_ATOMIC_IOMAP
2357 config X86_DEV_DMA_OPS
2359 depends on X86_64 || STA2X11
2361 config X86_DMA_REMAP
2365 source "net/Kconfig"
2367 source "drivers/Kconfig"
2369 source "drivers/firmware/Kconfig"
2373 source "arch/x86/Kconfig.debug"
2375 source "security/Kconfig"
2377 source "crypto/Kconfig"
2379 source "arch/x86/kvm/Kconfig"
2381 source "lib/Kconfig"
projects / ~andy / linux / blob