3 bool "64-bit kernel" if ARCH = "x86"
4 default ARCH = "x86_64"
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
15 select X86_DEV_DMA_OPS
20 select HAVE_AOUT if X86_32
21 select HAVE_UNSTABLE_SCHED_CLOCK
24 select HAVE_PCSPKR_PLATFORM
25 select HAVE_PERF_EVENTS
27 select HAVE_IOREMAP_PROT
30 select HAVE_MEMBLOCK_NODE_MAP
31 select ARCH_DISCARD_MEMBLOCK
32 select ARCH_WANT_OPTIONAL_GPIOLIB
33 select ARCH_WANT_FRAME_POINTERS
35 select HAVE_DMA_CONTIGUOUS if !SWIOTLB
36 select HAVE_KRETPROBES
38 select HAVE_FTRACE_MCOUNT_RECORD
39 select HAVE_FENTRY if X86_64
40 select HAVE_C_RECORDMCOUNT
41 select HAVE_DYNAMIC_FTRACE
42 select HAVE_FUNCTION_TRACER
43 select HAVE_FUNCTION_GRAPH_TRACER
44 select HAVE_FUNCTION_GRAPH_FP_TEST
45 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
46 select HAVE_SYSCALL_TRACEPOINTS
49 select HAVE_ARCH_TRACEHOOK
50 select HAVE_GENERIC_DMA_COHERENT if X86_32
51 select HAVE_EFFICIENT_UNALIGNED_ACCESS
52 select USER_STACKTRACE_SUPPORT
53 select HAVE_REGS_AND_STACK_ACCESS_API
54 select HAVE_DMA_API_DEBUG
55 select HAVE_KERNEL_GZIP
56 select HAVE_KERNEL_BZIP2
57 select HAVE_KERNEL_LZMA
59 select HAVE_KERNEL_LZO
60 select HAVE_HW_BREAKPOINT
61 select HAVE_MIXED_BREAKPOINTS_REGS
63 select HAVE_PERF_EVENTS_NMI
65 select HAVE_PERF_USER_STACK_DUMP
67 select HAVE_ALIGNED_STRUCT_PAGE if SLUB && !M386
68 select HAVE_CMPXCHG_LOCAL if !M386
69 select HAVE_CMPXCHG_DOUBLE
70 select HAVE_ARCH_KMEMCHECK
71 select HAVE_USER_RETURN_NOTIFIER
72 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
73 select HAVE_ARCH_JUMP_LABEL
74 select HAVE_TEXT_POKE_SMP
75 select HAVE_GENERIC_HARDIRQS
76 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
78 select GENERIC_FIND_FIRST_BIT
79 select GENERIC_IRQ_PROBE
80 select GENERIC_PENDING_IRQ if SMP
81 select GENERIC_IRQ_SHOW
82 select GENERIC_CLOCKEVENTS_MIN_ADJUST
83 select IRQ_FORCED_THREADING
84 select USE_GENERIC_SMP_HELPERS if SMP
85 select HAVE_BPF_JIT if X86_64
87 select ARCH_HAVE_NMI_SAFE_CMPXCHG
89 select DCACHE_WORD_ACCESS
90 select GENERIC_SMP_IDLE_THREAD
91 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
92 select HAVE_ARCH_SECCOMP_FILTER
93 select BUILDTIME_EXTABLE_SORT
94 select GENERIC_CMOS_UPDATE
95 select CLOCKSOURCE_WATCHDOG
96 select GENERIC_CLOCKEVENTS
97 select ARCH_CLOCKSOURCE_DATA if X86_64
98 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
99 select GENERIC_TIME_VSYSCALL if X86_64
100 select KTIME_SCALAR if X86_32
101 select GENERIC_STRNCPY_FROM_USER
102 select GENERIC_STRNLEN_USER
103 select HAVE_RCU_USER_QS if X86_64
105 config INSTRUCTION_DECODER
106 def_bool (KPROBES || PERF_EVENTS || UPROBES)
110 default "elf32-i386" if X86_32
111 default "elf64-x86-64" if X86_64
113 config ARCH_DEFCONFIG
115 default "arch/x86/configs/i386_defconfig" if X86_32
116 default "arch/x86/configs/x86_64_defconfig" if X86_64
118 config LOCKDEP_SUPPORT
121 config STACKTRACE_SUPPORT
124 config HAVE_LATENCYTOP_SUPPORT
133 config NEED_DMA_MAP_STATE
134 def_bool (X86_64 || INTEL_IOMMU || DMA_API_DEBUG)
136 config NEED_SG_DMA_LENGTH
139 config GENERIC_ISA_DMA
145 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
147 config GENERIC_BUG_RELATIVE_POINTERS
150 config GENERIC_HWEIGHT
156 config ARCH_MAY_HAVE_PC_FDC
159 config RWSEM_GENERIC_SPINLOCK
162 config RWSEM_XCHGADD_ALGORITHM
165 config GENERIC_CALIBRATE_DELAY
168 config ARCH_HAS_CPU_RELAX
171 config ARCH_HAS_DEFAULT_IDLE
174 config ARCH_HAS_CACHE_LINE_SIZE
177 config ARCH_HAS_CPU_AUTOPROBE
180 config HAVE_SETUP_PER_CPU_AREA
183 config NEED_PER_CPU_EMBED_FIRST_CHUNK
186 config NEED_PER_CPU_PAGE_FIRST_CHUNK
189 config ARCH_HIBERNATION_POSSIBLE
192 config ARCH_SUSPEND_POSSIBLE
203 config ARCH_SUPPORTS_OPTIMIZED_INLINING
206 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
209 config HAVE_INTEL_TXT
211 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
215 depends on X86_32 && SMP
219 depends on X86_64 && SMP
225 config X86_32_LAZY_GS
227 depends on X86_32 && !CC_STACKPROTECTOR
229 config ARCH_HWEIGHT_CFLAGS
231 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
232 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
234 config ARCH_CPU_PROBE_RELEASE
236 depends on HOTPLUG_CPU
238 config ARCH_SUPPORTS_UPROBES
241 source "init/Kconfig"
242 source "kernel/Kconfig.freezer"
244 menu "Processor type and features"
247 bool "DMA memory allocation support" if EXPERT
250 DMA memory allocation support allows devices with less than 32-bit
251 addressing to allocate within the first 16MB of address space.
252 Disable if no such devices will be used.
257 bool "Symmetric multi-processing support"
259 This enables support for systems with more than one CPU. If you have
260 a system with only one CPU, like most personal computers, say N. If
261 you have a system with more than one CPU, say Y.
263 If you say N here, the kernel will run on single and multiprocessor
264 machines, but will use only one CPU of a multiprocessor machine. If
265 you say Y here, the kernel will run on many, but not all,
266 singleprocessor machines. On a singleprocessor machine, the kernel
267 will run faster if you say N here.
269 Note that if you say Y here and choose architecture "586" or
270 "Pentium" under "Processor family", the kernel will not work on 486
271 architectures. Similarly, multiprocessor kernels for the "PPro"
272 architecture may not work on all Pentium based boards.
274 People using multiprocessor machines who say Y here should also say
275 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
276 Management" code will be disabled if you say Y here.
278 See also <file:Documentation/x86/i386/IO-APIC.txt>,
279 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
280 <http://www.tldp.org/docs.html#howto>.
282 If you don't know what to do here, say N.
285 bool "Support x2apic"
286 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
288 This enables x2apic support on CPUs that have this feature.
290 This allows 32-bit apic IDs (so it can support very large systems),
291 and accesses the local apic via MSRs not via mmio.
293 If you don't know what to do here, say N.
296 bool "Enable MPS table" if ACPI
298 depends on X86_LOCAL_APIC
300 For old smp systems that do not have proper acpi support. Newer systems
301 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
304 bool "Support for big SMP systems with more than 8 CPUs"
305 depends on X86_32 && SMP
307 This option is needed for the systems that have more than 8 CPUs
310 config X86_EXTENDED_PLATFORM
311 bool "Support for extended (non-PC) x86 platforms"
314 If you disable this option then the kernel will only support
315 standard PC platforms. (which covers the vast majority of
318 If you enable this option then you'll be able to select support
319 for the following (non-PC) 32 bit x86 platforms:
323 SGI 320/540 (Visual Workstation)
324 STA2X11-based (e.g. Northville)
325 Summit/EXA (IBM x440)
326 Unisys ES7000 IA32 series
327 Moorestown MID devices
329 If you have one of these systems, or if you want to build a
330 generic distribution kernel, say Y here - otherwise say N.
334 config X86_EXTENDED_PLATFORM
335 bool "Support for extended (non-PC) x86 platforms"
338 If you disable this option then the kernel will only support
339 standard PC platforms. (which covers the vast majority of
342 If you enable this option then you'll be able to select support
343 for the following (non-PC) 64 bit x86 platforms:
348 If you have one of these systems, or if you want to build a
349 generic distribution kernel, say Y here - otherwise say N.
351 # This is an alphabetically sorted list of 64 bit extended platforms
352 # Please maintain the alphabetic order if and when there are additions
354 bool "Numascale NumaChip"
356 depends on X86_EXTENDED_PLATFORM
359 depends on X86_X2APIC
361 Adds support for Numascale NumaChip large-SMP systems. Needed to
362 enable more than ~168 cores.
363 If you don't have one of these, you should say N here.
367 select PARAVIRT_GUEST
369 depends on X86_64 && PCI
370 depends on X86_EXTENDED_PLATFORM
373 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
374 supposed to run on these EM64T-based machines. Only choose this option
375 if you have one of these machines.
378 bool "SGI Ultraviolet"
380 depends on X86_EXTENDED_PLATFORM
382 depends on X86_X2APIC
384 This option is needed in order to support SGI Ultraviolet systems.
385 If you don't have one of these, you should say N here.
387 # Following is an alphabetically sorted list of 32 bit extended platforms
388 # Please maintain the alphabetic order if and when there are additions
391 bool "CE4100 TV platform"
393 depends on PCI_GODIRECT
395 depends on X86_EXTENDED_PLATFORM
396 select X86_REBOOTFIXUPS
398 select OF_EARLY_FLATTREE
401 Select for the Intel CE media processor (CE4100) SOC.
402 This option compiles in support for the CE4100 SOC for settop
403 boxes and media devices.
405 config X86_WANT_INTEL_MID
406 bool "Intel MID platform support"
408 depends on X86_EXTENDED_PLATFORM
410 Select to build a kernel capable of supporting Intel MID platform
411 systems which do not have the PCI legacy interfaces (Moorestown,
412 Medfield). If you are building for a PC class system say N here.
414 if X86_WANT_INTEL_MID
420 bool "Medfield MID platform"
423 depends on X86_IO_APIC
431 select X86_PLATFORM_DEVICES
432 select MFD_INTEL_MSIC
434 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
435 Internet Device(MID) platform.
436 Unlike standard x86 PCs, Medfield does not have many legacy devices
437 nor standard legacy replacement devices/features. e.g. Medfield does
438 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
443 bool "RDC R-321x SoC"
445 depends on X86_EXTENDED_PLATFORM
447 select X86_REBOOTFIXUPS
449 This option is needed for RDC R-321x system-on-chip, also known
451 If you don't have one of these chips, you should say N here.
453 config X86_32_NON_STANDARD
454 bool "Support non-standard 32-bit SMP architectures"
455 depends on X86_32 && SMP
456 depends on X86_EXTENDED_PLATFORM
458 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
459 STA2X11, default subarchitectures. It is intended for a generic
460 binary kernel. If you select them all, kernel will probe it
461 one by one and will fallback to default.
463 # Alphabetically sorted list of Non standard 32 bit platforms
466 bool "NUMAQ (IBM/Sequent)"
467 depends on X86_32_NON_STANDARD
472 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
473 NUMA multiquad box. This changes the way that processors are
474 bootstrapped, and uses Clustered Logical APIC addressing mode instead
475 of Flat Logical. You will need a new lynxer.elf file to flash your
476 firmware with - send email to <Martin.Bligh@us.ibm.com>.
478 config X86_SUPPORTS_MEMORY_FAILURE
480 # MCE code calls memory_failure():
482 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
483 depends on !X86_NUMAQ
484 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
485 depends on X86_64 || !SPARSEMEM
486 select ARCH_SUPPORTS_MEMORY_FAILURE
489 bool "SGI 320/540 (Visual Workstation)"
490 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
491 depends on X86_32_NON_STANDARD
493 The SGI Visual Workstation series is an IA32-based workstation
494 based on SGI systems chips with some legacy PC hardware attached.
496 Say Y here to create a kernel to run on the SGI 320 or 540.
498 A kernel compiled for the Visual Workstation will run on general
499 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
502 bool "STA2X11 Companion Chip Support"
503 depends on X86_32_NON_STANDARD && PCI
504 select X86_DEV_DMA_OPS
508 select ARCH_REQUIRE_GPIOLIB
511 This adds support for boards based on the STA2X11 IO-Hub,
512 a.k.a. "ConneXt". The chip is used in place of the standard
513 PC chipset, so all "standard" peripherals are missing. If this
514 option is selected the kernel will still be able to boot on
515 standard PC machines.
518 bool "Summit/EXA (IBM x440)"
519 depends on X86_32_NON_STANDARD
521 This option is needed for IBM systems that use the Summit/EXA chipset.
522 In particular, it is needed for the x440.
525 bool "Unisys ES7000 IA32 series"
526 depends on X86_32_NON_STANDARD && X86_BIGSMP
528 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
529 supposed to run on an IA32-based Unisys ES7000 system.
532 tristate "Eurobraille/Iris poweroff module"
535 The Iris machines from EuroBraille do not have APM or ACPI support
536 to shut themselves down properly. A special I/O sequence is
537 needed to do so, which is what this module does at
540 This is only for Iris machines from EuroBraille.
544 config SCHED_OMIT_FRAME_POINTER
546 prompt "Single-depth WCHAN output"
549 Calculate simpler /proc/<PID>/wchan values. If this option
550 is disabled then wchan values will recurse back to the
551 caller function. This provides more accurate wchan values,
552 at the expense of slightly more scheduling overhead.
554 If in doubt, say "Y".
556 menuconfig PARAVIRT_GUEST
557 bool "Paravirtualized guest support"
559 Say Y here to get to see options related to running Linux under
560 various hypervisors. This option alone does not add any kernel code.
562 If you say N, all options in this submenu will be skipped and disabled.
566 config PARAVIRT_TIME_ACCOUNTING
567 bool "Paravirtual steal time accounting"
571 Select this option to enable fine granularity task steal time
572 accounting. Time spent executing other tasks in parallel with
573 the current vCPU is discounted from the vCPU power. To account for
574 that, there can be a small performance impact.
576 If in doubt, say N here.
578 source "arch/x86/xen/Kconfig"
581 bool "KVM paravirtualized clock"
583 select PARAVIRT_CLOCK
585 Turning on this option will allow you to run a paravirtualized clock
586 when running over the KVM hypervisor. Instead of relying on a PIT
587 (or probably other) emulation by the underlying device model, the host
588 provides the guest with timing infrastructure such as time of day, and
592 bool "KVM Guest support"
595 This option enables various optimizations for running under the KVM
598 source "arch/x86/lguest/Kconfig"
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_SPINLOCKS
609 bool "Paravirtualization layer for spinlocks"
610 depends on PARAVIRT && SMP && EXPERIMENTAL
612 Paravirtualized spinlocks allow a pvops backend to replace the
613 spinlock implementation with something virtualization-friendly
614 (for example, block the virtual CPU rather than spinning).
616 Unfortunately the downside is an up to 5% performance hit on
617 native kernels, with various workloads.
619 If you are unsure how to answer this question, answer N.
621 config PARAVIRT_CLOCK
626 config PARAVIRT_DEBUG
627 bool "paravirt-ops debugging"
628 depends on PARAVIRT && DEBUG_KERNEL
630 Enable to debug paravirt_ops internals. Specifically, BUG if
631 a paravirt_op is missing when it is called.
639 This option adds a kernel parameter 'memtest', which allows memtest
641 memtest=0, mean disabled; -- default
642 memtest=1, mean do 1 test pattern;
644 memtest=4, mean do 4 test patterns.
645 If you are unsure how to answer this question, answer N.
647 config X86_SUMMIT_NUMA
649 depends on X86_32 && NUMA && X86_32_NON_STANDARD
651 config X86_CYCLONE_TIMER
653 depends on X86_SUMMIT
655 source "arch/x86/Kconfig.cpu"
659 prompt "HPET Timer Support" if X86_32
661 Use the IA-PC HPET (High Precision Event Timer) to manage
662 time in preference to the PIT and RTC, if a HPET is
664 HPET is the next generation timer replacing legacy 8254s.
665 The HPET provides a stable time base on SMP
666 systems, unlike the TSC, but it is more expensive to access,
667 as it is off-chip. You can find the HPET spec at
668 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
670 You can safely choose Y here. However, HPET will only be
671 activated if the platform and the BIOS support this feature.
672 Otherwise the 8254 will be used for timing services.
674 Choose N to continue using the legacy 8254 timer.
676 config HPET_EMULATE_RTC
678 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
681 def_bool y if X86_INTEL_MID
682 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
684 depends on X86_INTEL_MID && SFI
686 APB timer is the replacement for 8254, HPET on X86 MID platforms.
687 The APBT provides a stable time base on SMP
688 systems, unlike the TSC, but it is more expensive to access,
689 as it is off-chip. APB timers are always running regardless of CPU
690 C states, they are used as per CPU clockevent device when possible.
692 # Mark as expert because too many people got it wrong.
693 # The code disables itself when not needed.
696 bool "Enable DMI scanning" if EXPERT
698 Enabled scanning of DMI to identify machine quirks. Say Y
699 here unless you have verified that your setup is not
700 affected by entries in the DMI blacklist. Required by PNP
704 bool "GART IOMMU support" if EXPERT
707 depends on X86_64 && PCI && AMD_NB
709 Support for full DMA access of devices with 32bit memory access only
710 on systems with more than 3GB. This is usually needed for USB,
711 sound, many IDE/SATA chipsets and some other devices.
712 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
713 based hardware IOMMU and a software bounce buffer based IOMMU used
714 on Intel systems and as fallback.
715 The code is only active when needed (enough memory and limited
716 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
720 bool "IBM Calgary IOMMU support"
722 depends on X86_64 && PCI && EXPERIMENTAL
724 Support for hardware IOMMUs in IBM's xSeries x366 and x460
725 systems. Needed to run systems with more than 3GB of memory
726 properly with 32-bit PCI devices that do not support DAC
727 (Double Address Cycle). Calgary also supports bus level
728 isolation, where all DMAs pass through the IOMMU. This
729 prevents them from going anywhere except their intended
730 destination. This catches hard-to-find kernel bugs and
731 mis-behaving drivers and devices that do not use the DMA-API
732 properly to set up their DMA buffers. The IOMMU can be
733 turned off at boot time with the iommu=off parameter.
734 Normally the kernel will make the right choice by itself.
737 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
739 prompt "Should Calgary be enabled by default?"
740 depends on CALGARY_IOMMU
742 Should Calgary be enabled by default? if you choose 'y', Calgary
743 will be used (if it exists). If you choose 'n', Calgary will not be
744 used even if it exists. If you choose 'n' and would like to use
745 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
748 # need this always selected by IOMMU for the VIA workaround
752 Support for software bounce buffers used on x86-64 systems
753 which don't have a hardware IOMMU. Using this PCI devices
754 which can only access 32-bits of memory can be used on systems
755 with more than 3 GB of memory.
759 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
762 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
763 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
764 select CPUMASK_OFFSTACK
766 Enable maximum number of CPUS and NUMA Nodes for this architecture.
770 int "Maximum number of CPUs" if SMP && !MAXSMP
771 range 2 8 if SMP && X86_32 && !X86_BIGSMP
772 range 2 512 if SMP && !MAXSMP
774 default "4096" if MAXSMP
775 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
778 This allows you to specify the maximum number of CPUs which this
779 kernel will support. The maximum supported value is 512 and the
780 minimum value which makes sense is 2.
782 This is purely to save memory - each supported CPU adds
783 approximately eight kilobytes to the kernel image.
786 bool "SMT (Hyperthreading) scheduler support"
789 SMT scheduler support improves the CPU scheduler's decision making
790 when dealing with Intel Pentium 4 chips with HyperThreading at a
791 cost of slightly increased overhead in some places. If unsure say
796 prompt "Multi-core scheduler support"
799 Multi-core scheduler support improves the CPU scheduler's decision
800 making when dealing with multi-core CPU chips at a cost of slightly
801 increased overhead in some places. If unsure say N here.
803 config IRQ_TIME_ACCOUNTING
804 bool "Fine granularity task level IRQ time accounting"
807 Select this option to enable fine granularity task irq time
808 accounting. This is done by reading a timestamp on each
809 transitions between softirq and hardirq state, so there can be a
810 small performance impact.
812 If in doubt, say N here.
814 source "kernel/Kconfig.preempt"
817 bool "Local APIC support on uniprocessors"
818 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
820 A local APIC (Advanced Programmable Interrupt Controller) is an
821 integrated interrupt controller in the CPU. If you have a single-CPU
822 system which has a processor with a local APIC, you can say Y here to
823 enable and use it. If you say Y here even though your machine doesn't
824 have a local APIC, then the kernel will still run with no slowdown at
825 all. The local APIC supports CPU-generated self-interrupts (timer,
826 performance counters), and the NMI watchdog which detects hard
830 bool "IO-APIC support on uniprocessors"
831 depends on X86_UP_APIC
833 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
834 SMP-capable replacement for PC-style interrupt controllers. Most
835 SMP systems and many recent uniprocessor systems have one.
837 If you have a single-CPU system with an IO-APIC, you can say Y here
838 to use it. If you say Y here even though your machine doesn't have
839 an IO-APIC, then the kernel will still run with no slowdown at all.
841 config X86_LOCAL_APIC
843 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
847 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
849 config X86_VISWS_APIC
851 depends on X86_32 && X86_VISWS
853 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
854 bool "Reroute for broken boot IRQs"
855 depends on X86_IO_APIC
857 This option enables a workaround that fixes a source of
858 spurious interrupts. This is recommended when threaded
859 interrupt handling is used on systems where the generation of
860 superfluous "boot interrupts" cannot be disabled.
862 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
863 entry in the chipset's IO-APIC is masked (as, e.g. the RT
864 kernel does during interrupt handling). On chipsets where this
865 boot IRQ generation cannot be disabled, this workaround keeps
866 the original IRQ line masked so that only the equivalent "boot
867 IRQ" is delivered to the CPUs. The workaround also tells the
868 kernel to set up the IRQ handler on the boot IRQ line. In this
869 way only one interrupt is delivered to the kernel. Otherwise
870 the spurious second interrupt may cause the kernel to bring
871 down (vital) interrupt lines.
873 Only affects "broken" chipsets. Interrupt sharing may be
874 increased on these systems.
877 bool "Machine Check / overheating reporting"
879 Machine Check support allows the processor to notify the
880 kernel if it detects a problem (e.g. overheating, data corruption).
881 The action the kernel takes depends on the severity of the problem,
882 ranging from warning messages to halting the machine.
886 prompt "Intel MCE features"
887 depends on X86_MCE && X86_LOCAL_APIC
889 Additional support for intel specific MCE features such as
894 prompt "AMD MCE features"
895 depends on X86_MCE && X86_LOCAL_APIC
897 Additional support for AMD specific MCE features such as
898 the DRAM Error Threshold.
900 config X86_ANCIENT_MCE
901 bool "Support for old Pentium 5 / WinChip machine checks"
902 depends on X86_32 && X86_MCE
904 Include support for machine check handling on old Pentium 5 or WinChip
905 systems. These typically need to be enabled explicitely on the command
908 config X86_MCE_THRESHOLD
909 depends on X86_MCE_AMD || X86_MCE_INTEL
912 config X86_MCE_INJECT
914 tristate "Machine check injector support"
916 Provide support for injecting machine checks for testing purposes.
917 If you don't know what a machine check is and you don't do kernel
918 QA it is safe to say n.
920 config X86_THERMAL_VECTOR
922 depends on X86_MCE_INTEL
925 bool "Enable VM86 support" if EXPERT
929 This option is required by programs like DOSEMU to run 16-bit legacy
930 code on X86 processors. It also may be needed by software like
931 XFree86 to initialize some video cards via BIOS. Disabling this
932 option saves about 6k.
935 tristate "Toshiba Laptop support"
938 This adds a driver to safely access the System Management Mode of
939 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
940 not work on models with a Phoenix BIOS. The System Management Mode
941 is used to set the BIOS and power saving options on Toshiba portables.
943 For information on utilities to make use of this driver see the
944 Toshiba Linux utilities web site at:
945 <http://www.buzzard.org.uk/toshiba/>.
947 Say Y if you intend to run this kernel on a Toshiba portable.
951 tristate "Dell laptop support"
954 This adds a driver to safely access the System Management Mode
955 of the CPU on the Dell Inspiron 8000. The System Management Mode
956 is used to read cpu temperature and cooling fan status and to
957 control the fans on the I8K portables.
959 This driver has been tested only on the Inspiron 8000 but it may
960 also work with other Dell laptops. You can force loading on other
961 models by passing the parameter `force=1' to the module. Use at
964 For information on utilities to make use of this driver see the
965 I8K Linux utilities web site at:
966 <http://people.debian.org/~dz/i8k/>
968 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
971 config X86_REBOOTFIXUPS
972 bool "Enable X86 board specific fixups for reboot"
975 This enables chipset and/or board specific fixups to be done
976 in order to get reboot to work correctly. This is only needed on
977 some combinations of hardware and BIOS. The symptom, for which
978 this config is intended, is when reboot ends with a stalled/hung
981 Currently, the only fixup is for the Geode machines using
982 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
984 Say Y if you want to enable the fixup. Currently, it's safe to
985 enable this option even if you don't need it.
989 tristate "/dev/cpu/microcode - microcode support"
992 If you say Y here, you will be able to update the microcode on
993 certain Intel and AMD processors. The Intel support is for the
994 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
995 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
996 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
997 You will obviously need the actual microcode binary data itself
998 which is not shipped with the Linux kernel.
1000 This option selects the general module only, you need to select
1001 at least one vendor specific module as well.
1003 To compile this driver as a module, choose M here: the
1004 module will be called microcode.
1006 config MICROCODE_INTEL
1007 bool "Intel microcode patch loading support"
1008 depends on MICROCODE
1012 This options enables microcode patch loading support for Intel
1015 For latest news and information on obtaining all the required
1016 Intel ingredients for this driver, check:
1017 <http://www.urbanmyth.org/microcode/>.
1019 config MICROCODE_AMD
1020 bool "AMD microcode patch loading support"
1021 depends on MICROCODE
1024 If you select this option, microcode patch loading support for AMD
1025 processors will be enabled.
1027 config MICROCODE_OLD_INTERFACE
1029 depends on MICROCODE
1032 tristate "/dev/cpu/*/msr - Model-specific register support"
1034 This device gives privileged processes access to the x86
1035 Model-Specific Registers (MSRs). It is a character device with
1036 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1037 MSR accesses are directed to a specific CPU on multi-processor
1041 tristate "/dev/cpu/*/cpuid - CPU information support"
1043 This device gives processes access to the x86 CPUID instruction to
1044 be executed on a specific processor. It is a character device
1045 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1049 prompt "High Memory Support"
1050 default HIGHMEM64G if X86_NUMAQ
1056 depends on !X86_NUMAQ
1058 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1059 However, the address space of 32-bit x86 processors is only 4
1060 Gigabytes large. That means that, if you have a large amount of
1061 physical memory, not all of it can be "permanently mapped" by the
1062 kernel. The physical memory that's not permanently mapped is called
1065 If you are compiling a kernel which will never run on a machine with
1066 more than 1 Gigabyte total physical RAM, answer "off" here (default
1067 choice and suitable for most users). This will result in a "3GB/1GB"
1068 split: 3GB are mapped so that each process sees a 3GB virtual memory
1069 space and the remaining part of the 4GB virtual memory space is used
1070 by the kernel to permanently map as much physical memory as
1073 If the machine has between 1 and 4 Gigabytes physical RAM, then
1076 If more than 4 Gigabytes is used then answer "64GB" here. This
1077 selection turns Intel PAE (Physical Address Extension) mode on.
1078 PAE implements 3-level paging on IA32 processors. PAE is fully
1079 supported by Linux, PAE mode is implemented on all recent Intel
1080 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1081 then the kernel will not boot on CPUs that don't support PAE!
1083 The actual amount of total physical memory will either be
1084 auto detected or can be forced by using a kernel command line option
1085 such as "mem=256M". (Try "man bootparam" or see the documentation of
1086 your boot loader (lilo or loadlin) about how to pass options to the
1087 kernel at boot time.)
1089 If unsure, say "off".
1093 depends on !X86_NUMAQ
1095 Select this if you have a 32-bit processor and between 1 and 4
1096 gigabytes of physical RAM.
1100 depends on !M386 && !M486
1103 Select this if you have a 32-bit processor and more than 4
1104 gigabytes of physical RAM.
1109 depends on EXPERIMENTAL
1110 prompt "Memory split" if EXPERT
1114 Select the desired split between kernel and user memory.
1116 If the address range available to the kernel is less than the
1117 physical memory installed, the remaining memory will be available
1118 as "high memory". Accessing high memory is a little more costly
1119 than low memory, as it needs to be mapped into the kernel first.
1120 Note that increasing the kernel address space limits the range
1121 available to user programs, making the address space there
1122 tighter. Selecting anything other than the default 3G/1G split
1123 will also likely make your kernel incompatible with binary-only
1126 If you are not absolutely sure what you are doing, leave this
1130 bool "3G/1G user/kernel split"
1131 config VMSPLIT_3G_OPT
1133 bool "3G/1G user/kernel split (for full 1G low memory)"
1135 bool "2G/2G user/kernel split"
1136 config VMSPLIT_2G_OPT
1138 bool "2G/2G user/kernel split (for full 2G low memory)"
1140 bool "1G/3G user/kernel split"
1145 default 0xB0000000 if VMSPLIT_3G_OPT
1146 default 0x80000000 if VMSPLIT_2G
1147 default 0x78000000 if VMSPLIT_2G_OPT
1148 default 0x40000000 if VMSPLIT_1G
1154 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1157 bool "PAE (Physical Address Extension) Support"
1158 depends on X86_32 && !HIGHMEM4G
1160 PAE is required for NX support, and furthermore enables
1161 larger swapspace support for non-overcommit purposes. It
1162 has the cost of more pagetable lookup overhead, and also
1163 consumes more pagetable space per process.
1165 config ARCH_PHYS_ADDR_T_64BIT
1166 def_bool X86_64 || X86_PAE
1168 config ARCH_DMA_ADDR_T_64BIT
1169 def_bool X86_64 || HIGHMEM64G
1171 config DIRECT_GBPAGES
1172 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1176 Allow the kernel linear mapping to use 1GB pages on CPUs that
1177 support it. This can improve the kernel's performance a tiny bit by
1178 reducing TLB pressure. If in doubt, say "Y".
1180 # Common NUMA Features
1182 bool "Numa Memory Allocation and Scheduler Support"
1184 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1185 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1187 Enable NUMA (Non Uniform Memory Access) support.
1189 The kernel will try to allocate memory used by a CPU on the
1190 local memory controller of the CPU and add some more
1191 NUMA awareness to the kernel.
1193 For 64-bit this is recommended if the system is Intel Core i7
1194 (or later), AMD Opteron, or EM64T NUMA.
1196 For 32-bit this is only needed on (rare) 32-bit-only platforms
1197 that support NUMA topologies, such as NUMAQ / Summit, or if you
1198 boot a 32-bit kernel on a 64-bit NUMA platform.
1200 Otherwise, you should say N.
1202 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1203 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1207 prompt "Old style AMD Opteron NUMA detection"
1208 depends on X86_64 && NUMA && PCI
1210 Enable AMD NUMA node topology detection. You should say Y here if
1211 you have a multi processor AMD system. This uses an old method to
1212 read the NUMA configuration directly from the builtin Northbridge
1213 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1214 which also takes priority if both are compiled in.
1216 config X86_64_ACPI_NUMA
1218 prompt "ACPI NUMA detection"
1219 depends on X86_64 && NUMA && ACPI && PCI
1222 Enable ACPI SRAT based node topology detection.
1224 # Some NUMA nodes have memory ranges that span
1225 # other nodes. Even though a pfn is valid and
1226 # between a node's start and end pfns, it may not
1227 # reside on that node. See memmap_init_zone()
1229 config NODES_SPAN_OTHER_NODES
1231 depends on X86_64_ACPI_NUMA
1234 bool "NUMA emulation"
1237 Enable NUMA emulation. A flat machine will be split
1238 into virtual nodes when booted with "numa=fake=N", where N is the
1239 number of nodes. This is only useful for debugging.
1242 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1244 default "10" if MAXSMP
1245 default "6" if X86_64
1246 default "4" if X86_NUMAQ
1248 depends on NEED_MULTIPLE_NODES
1250 Specify the maximum number of NUMA Nodes available on the target
1251 system. Increases memory reserved to accommodate various tables.
1253 config HAVE_ARCH_ALLOC_REMAP
1255 depends on X86_32 && NUMA
1257 config ARCH_HAVE_MEMORY_PRESENT
1259 depends on X86_32 && DISCONTIGMEM
1261 config NEED_NODE_MEMMAP_SIZE
1263 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1265 config ARCH_FLATMEM_ENABLE
1267 depends on X86_32 && !NUMA
1269 config ARCH_DISCONTIGMEM_ENABLE
1271 depends on NUMA && X86_32
1273 config ARCH_DISCONTIGMEM_DEFAULT
1275 depends on NUMA && X86_32
1277 config ARCH_SPARSEMEM_ENABLE
1279 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1280 select SPARSEMEM_STATIC if X86_32
1281 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1283 config ARCH_SPARSEMEM_DEFAULT
1287 config ARCH_SELECT_MEMORY_MODEL
1289 depends on ARCH_SPARSEMEM_ENABLE
1291 config ARCH_MEMORY_PROBE
1293 depends on MEMORY_HOTPLUG
1295 config ARCH_PROC_KCORE_TEXT
1297 depends on X86_64 && PROC_KCORE
1299 config ILLEGAL_POINTER_VALUE
1302 default 0xdead000000000000 if X86_64
1307 bool "Allocate 3rd-level pagetables from highmem"
1310 The VM uses one page table entry for each page of physical memory.
1311 For systems with a lot of RAM, this can be wasteful of precious
1312 low memory. Setting this option will put user-space page table
1313 entries in high memory.
1315 config X86_CHECK_BIOS_CORRUPTION
1316 bool "Check for low memory corruption"
1318 Periodically check for memory corruption in low memory, which
1319 is suspected to be caused by BIOS. Even when enabled in the
1320 configuration, it is disabled at runtime. Enable it by
1321 setting "memory_corruption_check=1" on the kernel command
1322 line. By default it scans the low 64k of memory every 60
1323 seconds; see the memory_corruption_check_size and
1324 memory_corruption_check_period parameters in
1325 Documentation/kernel-parameters.txt to adjust this.
1327 When enabled with the default parameters, this option has
1328 almost no overhead, as it reserves a relatively small amount
1329 of memory and scans it infrequently. It both detects corruption
1330 and prevents it from affecting the running system.
1332 It is, however, intended as a diagnostic tool; if repeatable
1333 BIOS-originated corruption always affects the same memory,
1334 you can use memmap= to prevent the kernel from using that
1337 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1338 bool "Set the default setting of memory_corruption_check"
1339 depends on X86_CHECK_BIOS_CORRUPTION
1342 Set whether the default state of memory_corruption_check is
1345 config X86_RESERVE_LOW
1346 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1350 Specify the amount of low memory to reserve for the BIOS.
1352 The first page contains BIOS data structures that the kernel
1353 must not use, so that page must always be reserved.
1355 By default we reserve the first 64K of physical RAM, as a
1356 number of BIOSes are known to corrupt that memory range
1357 during events such as suspend/resume or monitor cable
1358 insertion, so it must not be used by the kernel.
1360 You can set this to 4 if you are absolutely sure that you
1361 trust the BIOS to get all its memory reservations and usages
1362 right. If you know your BIOS have problems beyond the
1363 default 64K area, you can set this to 640 to avoid using the
1364 entire low memory range.
1366 If you have doubts about the BIOS (e.g. suspend/resume does
1367 not work or there's kernel crashes after certain hardware
1368 hotplug events) then you might want to enable
1369 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1370 typical corruption patterns.
1372 Leave this to the default value of 64 if you are unsure.
1374 config MATH_EMULATION
1376 prompt "Math emulation" if X86_32
1378 Linux can emulate a math coprocessor (used for floating point
1379 operations) if you don't have one. 486DX and Pentium processors have
1380 a math coprocessor built in, 486SX and 386 do not, unless you added
1381 a 487DX or 387, respectively. (The messages during boot time can
1382 give you some hints here ["man dmesg"].) Everyone needs either a
1383 coprocessor or this emulation.
1385 If you don't have a math coprocessor, you need to say Y here; if you
1386 say Y here even though you have a coprocessor, the coprocessor will
1387 be used nevertheless. (This behavior can be changed with the kernel
1388 command line option "no387", which comes handy if your coprocessor
1389 is broken. Try "man bootparam" or see the documentation of your boot
1390 loader (lilo or loadlin) about how to pass options to the kernel at
1391 boot time.) This means that it is a good idea to say Y here if you
1392 intend to use this kernel on different machines.
1394 More information about the internals of the Linux math coprocessor
1395 emulation can be found in <file:arch/x86/math-emu/README>.
1397 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1398 kernel, it won't hurt.
1402 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1404 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1405 the Memory Type Range Registers (MTRRs) may be used to control
1406 processor access to memory ranges. This is most useful if you have
1407 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1408 allows bus write transfers to be combined into a larger transfer
1409 before bursting over the PCI/AGP bus. This can increase performance
1410 of image write operations 2.5 times or more. Saying Y here creates a
1411 /proc/mtrr file which may be used to manipulate your processor's
1412 MTRRs. Typically the X server should use this.
1414 This code has a reasonably generic interface so that similar
1415 control registers on other processors can be easily supported
1418 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1419 Registers (ARRs) which provide a similar functionality to MTRRs. For
1420 these, the ARRs are used to emulate the MTRRs.
1421 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1422 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1423 write-combining. All of these processors are supported by this code
1424 and it makes sense to say Y here if you have one of them.
1426 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1427 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1428 can lead to all sorts of problems, so it's good to say Y here.
1430 You can safely say Y even if your machine doesn't have MTRRs, you'll
1431 just add about 9 KB to your kernel.
1433 See <file:Documentation/x86/mtrr.txt> for more information.
1435 config MTRR_SANITIZER
1437 prompt "MTRR cleanup support"
1440 Convert MTRR layout from continuous to discrete, so X drivers can
1441 add writeback entries.
1443 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1444 The largest mtrr entry size for a continuous block can be set with
1449 config MTRR_SANITIZER_ENABLE_DEFAULT
1450 int "MTRR cleanup enable value (0-1)"
1453 depends on MTRR_SANITIZER
1455 Enable mtrr cleanup default value
1457 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1458 int "MTRR cleanup spare reg num (0-7)"
1461 depends on MTRR_SANITIZER
1463 mtrr cleanup spare entries default, it can be changed via
1464 mtrr_spare_reg_nr=N on the kernel command line.
1468 prompt "x86 PAT support" if EXPERT
1471 Use PAT attributes to setup page level cache control.
1473 PATs are the modern equivalents of MTRRs and are much more
1474 flexible than MTRRs.
1476 Say N here if you see bootup problems (boot crash, boot hang,
1477 spontaneous reboots) or a non-working video driver.
1481 config ARCH_USES_PG_UNCACHED
1487 prompt "x86 architectural random number generator" if EXPERT
1489 Enable the x86 architectural RDRAND instruction
1490 (Intel Bull Mountain technology) to generate random numbers.
1491 If supported, this is a high bandwidth, cryptographically
1492 secure hardware random number generator.
1495 bool "EFI runtime service support"
1498 This enables the kernel to use EFI runtime services that are
1499 available (such as the EFI variable services).
1501 This option is only useful on systems that have EFI firmware.
1502 In addition, you should use the latest ELILO loader available
1503 at <http://elilo.sourceforge.net> in order to take advantage
1504 of EFI runtime services. However, even with this option, the
1505 resultant kernel should continue to boot on existing non-EFI
1509 bool "EFI stub support"
1512 This kernel feature allows a bzImage to be loaded directly
1513 by EFI firmware without the use of a bootloader.
1515 See Documentation/x86/efi-stub.txt for more information.
1519 prompt "Enable seccomp to safely compute untrusted bytecode"
1521 This kernel feature is useful for number crunching applications
1522 that may need to compute untrusted bytecode during their
1523 execution. By using pipes or other transports made available to
1524 the process as file descriptors supporting the read/write
1525 syscalls, it's possible to isolate those applications in
1526 their own address space using seccomp. Once seccomp is
1527 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1528 and the task is only allowed to execute a few safe syscalls
1529 defined by each seccomp mode.
1531 If unsure, say Y. Only embedded should say N here.
1533 config CC_STACKPROTECTOR
1534 bool "Enable -fstack-protector buffer overflow detection"
1536 This option turns on the -fstack-protector GCC feature. This
1537 feature puts, at the beginning of functions, a canary value on
1538 the stack just before the return address, and validates
1539 the value just before actually returning. Stack based buffer
1540 overflows (that need to overwrite this return address) now also
1541 overwrite the canary, which gets detected and the attack is then
1542 neutralized via a kernel panic.
1544 This feature requires gcc version 4.2 or above, or a distribution
1545 gcc with the feature backported. Older versions are automatically
1546 detected and for those versions, this configuration option is
1547 ignored. (and a warning is printed during bootup)
1549 source kernel/Kconfig.hz
1552 bool "kexec system call"
1554 kexec is a system call that implements the ability to shutdown your
1555 current kernel, and to start another kernel. It is like a reboot
1556 but it is independent of the system firmware. And like a reboot
1557 you can start any kernel with it, not just Linux.
1559 The name comes from the similarity to the exec system call.
1561 It is an ongoing process to be certain the hardware in a machine
1562 is properly shutdown, so do not be surprised if this code does not
1563 initially work for you. It may help to enable device hotplugging
1564 support. As of this writing the exact hardware interface is
1565 strongly in flux, so no good recommendation can be made.
1568 bool "kernel crash dumps"
1569 depends on X86_64 || (X86_32 && HIGHMEM)
1571 Generate crash dump after being started by kexec.
1572 This should be normally only set in special crash dump kernels
1573 which are loaded in the main kernel with kexec-tools into
1574 a specially reserved region and then later executed after
1575 a crash by kdump/kexec. The crash dump kernel must be compiled
1576 to a memory address not used by the main kernel or BIOS using
1577 PHYSICAL_START, or it must be built as a relocatable image
1578 (CONFIG_RELOCATABLE=y).
1579 For more details see Documentation/kdump/kdump.txt
1582 bool "kexec jump (EXPERIMENTAL)"
1583 depends on EXPERIMENTAL
1584 depends on KEXEC && HIBERNATION
1586 Jump between original kernel and kexeced kernel and invoke
1587 code in physical address mode via KEXEC
1589 config PHYSICAL_START
1590 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1593 This gives the physical address where the kernel is loaded.
1595 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1596 bzImage will decompress itself to above physical address and
1597 run from there. Otherwise, bzImage will run from the address where
1598 it has been loaded by the boot loader and will ignore above physical
1601 In normal kdump cases one does not have to set/change this option
1602 as now bzImage can be compiled as a completely relocatable image
1603 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1604 address. This option is mainly useful for the folks who don't want
1605 to use a bzImage for capturing the crash dump and want to use a
1606 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1607 to be specifically compiled to run from a specific memory area
1608 (normally a reserved region) and this option comes handy.
1610 So if you are using bzImage for capturing the crash dump,
1611 leave the value here unchanged to 0x1000000 and set
1612 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1613 for capturing the crash dump change this value to start of
1614 the reserved region. In other words, it can be set based on
1615 the "X" value as specified in the "crashkernel=YM@XM"
1616 command line boot parameter passed to the panic-ed
1617 kernel. Please take a look at Documentation/kdump/kdump.txt
1618 for more details about crash dumps.
1620 Usage of bzImage for capturing the crash dump is recommended as
1621 one does not have to build two kernels. Same kernel can be used
1622 as production kernel and capture kernel. Above option should have
1623 gone away after relocatable bzImage support is introduced. But it
1624 is present because there are users out there who continue to use
1625 vmlinux for dump capture. This option should go away down the
1628 Don't change this unless you know what you are doing.
1631 bool "Build a relocatable kernel"
1634 This builds a kernel image that retains relocation information
1635 so it can be loaded someplace besides the default 1MB.
1636 The relocations tend to make the kernel binary about 10% larger,
1637 but are discarded at runtime.
1639 One use is for the kexec on panic case where the recovery kernel
1640 must live at a different physical address than the primary
1643 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1644 it has been loaded at and the compile time physical address
1645 (CONFIG_PHYSICAL_START) is ignored.
1647 # Relocation on x86-32 needs some additional build support
1648 config X86_NEED_RELOCS
1650 depends on X86_32 && RELOCATABLE
1652 config PHYSICAL_ALIGN
1653 hex "Alignment value to which kernel should be aligned" if X86_32
1655 range 0x2000 0x1000000
1657 This value puts the alignment restrictions on physical address
1658 where kernel is loaded and run from. Kernel is compiled for an
1659 address which meets above alignment restriction.
1661 If bootloader loads the kernel at a non-aligned address and
1662 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1663 address aligned to above value and run from there.
1665 If bootloader loads the kernel at a non-aligned address and
1666 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1667 load address and decompress itself to the address it has been
1668 compiled for and run from there. The address for which kernel is
1669 compiled already meets above alignment restrictions. Hence the
1670 end result is that kernel runs from a physical address meeting
1671 above alignment restrictions.
1673 Don't change this unless you know what you are doing.
1676 bool "Support for hot-pluggable CPUs"
1677 depends on SMP && HOTPLUG
1679 Say Y here to allow turning CPUs off and on. CPUs can be
1680 controlled through /sys/devices/system/cpu.
1681 ( Note: power management support will enable this option
1682 automatically on SMP systems. )
1683 Say N if you want to disable CPU hotplug.
1687 prompt "Compat VDSO support"
1688 depends on X86_32 || IA32_EMULATION
1690 Map the 32-bit VDSO to the predictable old-style address too.
1692 Say N here if you are running a sufficiently recent glibc
1693 version (2.3.3 or later), to remove the high-mapped
1694 VDSO mapping and to exclusively use the randomized VDSO.
1699 bool "Built-in kernel command line"
1701 Allow for specifying boot arguments to the kernel at
1702 build time. On some systems (e.g. embedded ones), it is
1703 necessary or convenient to provide some or all of the
1704 kernel boot arguments with the kernel itself (that is,
1705 to not rely on the boot loader to provide them.)
1707 To compile command line arguments into the kernel,
1708 set this option to 'Y', then fill in the
1709 the boot arguments in CONFIG_CMDLINE.
1711 Systems with fully functional boot loaders (i.e. non-embedded)
1712 should leave this option set to 'N'.
1715 string "Built-in kernel command string"
1716 depends on CMDLINE_BOOL
1719 Enter arguments here that should be compiled into the kernel
1720 image and used at boot time. If the boot loader provides a
1721 command line at boot time, it is appended to this string to
1722 form the full kernel command line, when the system boots.
1724 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1725 change this behavior.
1727 In most cases, the command line (whether built-in or provided
1728 by the boot loader) should specify the device for the root
1731 config CMDLINE_OVERRIDE
1732 bool "Built-in command line overrides boot loader arguments"
1733 depends on CMDLINE_BOOL
1735 Set this option to 'Y' to have the kernel ignore the boot loader
1736 command line, and use ONLY the built-in command line.
1738 This is used to work around broken boot loaders. This should
1739 be set to 'N' under normal conditions.
1743 config ARCH_ENABLE_MEMORY_HOTPLUG
1745 depends on X86_64 || (X86_32 && HIGHMEM)
1747 config ARCH_ENABLE_MEMORY_HOTREMOVE
1749 depends on MEMORY_HOTPLUG
1751 config USE_PERCPU_NUMA_NODE_ID
1755 menu "Power management and ACPI options"
1757 config ARCH_HIBERNATION_HEADER
1759 depends on X86_64 && HIBERNATION
1761 source "kernel/power/Kconfig"
1763 source "drivers/acpi/Kconfig"
1765 source "drivers/sfi/Kconfig"
1772 tristate "APM (Advanced Power Management) BIOS support"
1773 depends on X86_32 && PM_SLEEP
1775 APM is a BIOS specification for saving power using several different
1776 techniques. This is mostly useful for battery powered laptops with
1777 APM compliant BIOSes. If you say Y here, the system time will be
1778 reset after a RESUME operation, the /proc/apm device will provide
1779 battery status information, and user-space programs will receive
1780 notification of APM "events" (e.g. battery status change).
1782 If you select "Y" here, you can disable actual use of the APM
1783 BIOS by passing the "apm=off" option to the kernel at boot time.
1785 Note that the APM support is almost completely disabled for
1786 machines with more than one CPU.
1788 In order to use APM, you will need supporting software. For location
1789 and more information, read <file:Documentation/power/apm-acpi.txt>
1790 and the Battery Powered Linux mini-HOWTO, available from
1791 <http://www.tldp.org/docs.html#howto>.
1793 This driver does not spin down disk drives (see the hdparm(8)
1794 manpage ("man 8 hdparm") for that), and it doesn't turn off
1795 VESA-compliant "green" monitors.
1797 This driver does not support the TI 4000M TravelMate and the ACER
1798 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1799 desktop machines also don't have compliant BIOSes, and this driver
1800 may cause those machines to panic during the boot phase.
1802 Generally, if you don't have a battery in your machine, there isn't
1803 much point in using this driver and you should say N. If you get
1804 random kernel OOPSes or reboots that don't seem to be related to
1805 anything, try disabling/enabling this option (or disabling/enabling
1808 Some other things you should try when experiencing seemingly random,
1811 1) make sure that you have enough swap space and that it is
1813 2) pass the "no-hlt" option to the kernel
1814 3) switch on floating point emulation in the kernel and pass
1815 the "no387" option to the kernel
1816 4) pass the "floppy=nodma" option to the kernel
1817 5) pass the "mem=4M" option to the kernel (thereby disabling
1818 all but the first 4 MB of RAM)
1819 6) make sure that the CPU is not over clocked.
1820 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1821 8) disable the cache from your BIOS settings
1822 9) install a fan for the video card or exchange video RAM
1823 10) install a better fan for the CPU
1824 11) exchange RAM chips
1825 12) exchange the motherboard.
1827 To compile this driver as a module, choose M here: the
1828 module will be called apm.
1832 config APM_IGNORE_USER_SUSPEND
1833 bool "Ignore USER SUSPEND"
1835 This option will ignore USER SUSPEND requests. On machines with a
1836 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1837 series notebooks, it is necessary to say Y because of a BIOS bug.
1839 config APM_DO_ENABLE
1840 bool "Enable PM at boot time"
1842 Enable APM features at boot time. From page 36 of the APM BIOS
1843 specification: "When disabled, the APM BIOS does not automatically
1844 power manage devices, enter the Standby State, enter the Suspend
1845 State, or take power saving steps in response to CPU Idle calls."
1846 This driver will make CPU Idle calls when Linux is idle (unless this
1847 feature is turned off -- see "Do CPU IDLE calls", below). This
1848 should always save battery power, but more complicated APM features
1849 will be dependent on your BIOS implementation. You may need to turn
1850 this option off if your computer hangs at boot time when using APM
1851 support, or if it beeps continuously instead of suspending. Turn
1852 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1853 T400CDT. This is off by default since most machines do fine without
1857 bool "Make CPU Idle calls when idle"
1859 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1860 On some machines, this can activate improved power savings, such as
1861 a slowed CPU clock rate, when the machine is idle. These idle calls
1862 are made after the idle loop has run for some length of time (e.g.,
1863 333 mS). On some machines, this will cause a hang at boot time or
1864 whenever the CPU becomes idle. (On machines with more than one CPU,
1865 this option does nothing.)
1867 config APM_DISPLAY_BLANK
1868 bool "Enable console blanking using APM"
1870 Enable console blanking using the APM. Some laptops can use this to
1871 turn off the LCD backlight when the screen blanker of the Linux
1872 virtual console blanks the screen. Note that this is only used by
1873 the virtual console screen blanker, and won't turn off the backlight
1874 when using the X Window system. This also doesn't have anything to
1875 do with your VESA-compliant power-saving monitor. Further, this
1876 option doesn't work for all laptops -- it might not turn off your
1877 backlight at all, or it might print a lot of errors to the console,
1878 especially if you are using gpm.
1880 config APM_ALLOW_INTS
1881 bool "Allow interrupts during APM BIOS calls"
1883 Normally we disable external interrupts while we are making calls to
1884 the APM BIOS as a measure to lessen the effects of a badly behaving
1885 BIOS implementation. The BIOS should reenable interrupts if it
1886 needs to. Unfortunately, some BIOSes do not -- especially those in
1887 many of the newer IBM Thinkpads. If you experience hangs when you
1888 suspend, try setting this to Y. Otherwise, say N.
1892 source "drivers/cpufreq/Kconfig"
1894 source "drivers/cpuidle/Kconfig"
1896 source "drivers/idle/Kconfig"
1901 menu "Bus options (PCI etc.)"
1906 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1908 Find out whether you have a PCI motherboard. PCI is the name of a
1909 bus system, i.e. the way the CPU talks to the other stuff inside
1910 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1911 VESA. If you have PCI, say Y, otherwise N.
1914 prompt "PCI access mode"
1915 depends on X86_32 && PCI
1918 On PCI systems, the BIOS can be used to detect the PCI devices and
1919 determine their configuration. However, some old PCI motherboards
1920 have BIOS bugs and may crash if this is done. Also, some embedded
1921 PCI-based systems don't have any BIOS at all. Linux can also try to
1922 detect the PCI hardware directly without using the BIOS.
1924 With this option, you can specify how Linux should detect the
1925 PCI devices. If you choose "BIOS", the BIOS will be used,
1926 if you choose "Direct", the BIOS won't be used, and if you
1927 choose "MMConfig", then PCI Express MMCONFIG will be used.
1928 If you choose "Any", the kernel will try MMCONFIG, then the
1929 direct access method and falls back to the BIOS if that doesn't
1930 work. If unsure, go with the default, which is "Any".
1935 config PCI_GOMMCONFIG
1952 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1954 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1957 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
1961 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1965 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1969 depends on PCI && XEN
1977 bool "Support mmconfig PCI config space access"
1978 depends on X86_64 && PCI && ACPI
1980 config PCI_CNB20LE_QUIRK
1981 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1983 depends on PCI && EXPERIMENTAL
1985 Read the PCI windows out of the CNB20LE host bridge. This allows
1986 PCI hotplug to work on systems with the CNB20LE chipset which do
1989 There's no public spec for this chipset, and this functionality
1990 is known to be incomplete.
1992 You should say N unless you know you need this.
1994 source "drivers/pci/pcie/Kconfig"
1996 source "drivers/pci/Kconfig"
1998 # x86_64 have no ISA slots, but can have ISA-style DMA.
2000 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2003 Enables ISA-style DMA support for devices requiring such controllers.
2011 Find out whether you have ISA slots on your motherboard. ISA is the
2012 name of a bus system, i.e. the way the CPU talks to the other stuff
2013 inside your box. Other bus systems are PCI, EISA, MicroChannel
2014 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2015 newer boards don't support it. If you have ISA, say Y, otherwise N.
2021 The Extended Industry Standard Architecture (EISA) bus was
2022 developed as an open alternative to the IBM MicroChannel bus.
2024 The EISA bus provided some of the features of the IBM MicroChannel
2025 bus while maintaining backward compatibility with cards made for
2026 the older ISA bus. The EISA bus saw limited use between 1988 and
2027 1995 when it was made obsolete by the PCI bus.
2029 Say Y here if you are building a kernel for an EISA-based machine.
2033 source "drivers/eisa/Kconfig"
2036 tristate "NatSemi SCx200 support"
2038 This provides basic support for National Semiconductor's
2039 (now AMD's) Geode processors. The driver probes for the
2040 PCI-IDs of several on-chip devices, so its a good dependency
2041 for other scx200_* drivers.
2043 If compiled as a module, the driver is named scx200.
2045 config SCx200HR_TIMER
2046 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2050 This driver provides a clocksource built upon the on-chip
2051 27MHz high-resolution timer. Its also a workaround for
2052 NSC Geode SC-1100's buggy TSC, which loses time when the
2053 processor goes idle (as is done by the scheduler). The
2054 other workaround is idle=poll boot option.
2057 bool "One Laptop Per Child support"
2064 Add support for detecting the unique features of the OLPC
2068 bool "OLPC XO-1 Power Management"
2069 depends on OLPC && MFD_CS5535 && PM_SLEEP
2072 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2075 bool "OLPC XO-1 Real Time Clock"
2076 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2078 Add support for the XO-1 real time clock, which can be used as a
2079 programmable wakeup source.
2082 bool "OLPC XO-1 SCI extras"
2083 depends on OLPC && OLPC_XO1_PM
2088 Add support for SCI-based features of the OLPC XO-1 laptop:
2089 - EC-driven system wakeups
2093 - AC adapter status updates
2094 - Battery status updates
2096 config OLPC_XO15_SCI
2097 bool "OLPC XO-1.5 SCI extras"
2098 depends on OLPC && ACPI
2101 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2102 - EC-driven system wakeups
2103 - AC adapter status updates
2104 - Battery status updates
2107 bool "PCEngines ALIX System Support (LED setup)"
2110 This option enables system support for the PCEngines ALIX.
2111 At present this just sets up LEDs for GPIO control on
2112 ALIX2/3/6 boards. However, other system specific setup should
2115 Note: You must still enable the drivers for GPIO and LED support
2116 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2118 Note: You have to set alix.force=1 for boards with Award BIOS.
2121 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2124 This option enables system support for the Soekris Engineering net5501.
2127 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2131 This option enables system support for the Traverse Technologies GEOS.
2137 depends on CPU_SUP_AMD && PCI
2139 source "drivers/pcmcia/Kconfig"
2141 source "drivers/pci/hotplug/Kconfig"
2144 bool "RapidIO support"
2148 If you say Y here, the kernel will include drivers and
2149 infrastructure code to support RapidIO interconnect devices.
2151 source "drivers/rapidio/Kconfig"
2156 menu "Executable file formats / Emulations"
2158 source "fs/Kconfig.binfmt"
2160 config IA32_EMULATION
2161 bool "IA32 Emulation"
2163 select COMPAT_BINFMT_ELF
2165 Include code to run legacy 32-bit programs under a
2166 64-bit kernel. You should likely turn this on, unless you're
2167 100% sure that you don't have any 32-bit programs left.
2170 tristate "IA32 a.out support"
2171 depends on IA32_EMULATION
2173 Support old a.out binaries in the 32bit emulation.
2176 bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
2177 depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
2179 Include code to run binaries for the x32 native 32-bit ABI
2180 for 64-bit processors. An x32 process gets access to the
2181 full 64-bit register file and wide data path while leaving
2182 pointers at 32 bits for smaller memory footprint.
2184 You will need a recent binutils (2.22 or later) with
2185 elf32_x86_64 support enabled to compile a kernel with this
2190 depends on IA32_EMULATION || X86_X32
2191 select ARCH_WANT_OLD_COMPAT_IPC
2193 config COMPAT_FOR_U64_ALIGNMENT
2197 config SYSVIPC_COMPAT
2199 depends on COMPAT && SYSVIPC
2203 depends on COMPAT && KEYS
2209 config HAVE_ATOMIC_IOMAP
2213 config HAVE_TEXT_POKE_SMP
2215 select STOP_MACHINE if SMP
2217 config X86_DEV_DMA_OPS
2219 depends on X86_64 || STA2X11
2221 config X86_DMA_REMAP
2225 source "net/Kconfig"
2227 source "drivers/Kconfig"
2229 source "drivers/firmware/Kconfig"
2233 source "arch/x86/Kconfig.debug"
2235 source "security/Kconfig"
2237 source "crypto/Kconfig"
2239 source "arch/x86/kvm/Kconfig"
2241 source "lib/Kconfig"