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
18 select HAVE_AOUT if X86_32
21 select HAVE_UNSTABLE_SCHED_CLOCK
24 select HAVE_PERF_EVENTS
26 select HAVE_IOREMAP_PROT
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
32 select HAVE_KRETPROBES
34 select HAVE_FTRACE_MCOUNT_RECORD
35 select HAVE_C_RECORDMCOUNT
36 select HAVE_DYNAMIC_FTRACE
37 select HAVE_FUNCTION_TRACER
38 select HAVE_FUNCTION_GRAPH_TRACER
39 select HAVE_FUNCTION_GRAPH_FP_TEST
40 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
41 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
42 select HAVE_SYSCALL_TRACEPOINTS
45 select HAVE_ARCH_TRACEHOOK
46 select HAVE_GENERIC_DMA_COHERENT if X86_32
47 select HAVE_EFFICIENT_UNALIGNED_ACCESS
48 select USER_STACKTRACE_SUPPORT
49 select HAVE_REGS_AND_STACK_ACCESS_API
50 select HAVE_DMA_API_DEBUG
51 select HAVE_KERNEL_GZIP
52 select HAVE_KERNEL_BZIP2
53 select HAVE_KERNEL_LZMA
55 select HAVE_KERNEL_LZO
56 select HAVE_HW_BREAKPOINT
57 select HAVE_MIXED_BREAKPOINTS_REGS
59 select HAVE_PERF_EVENTS_NMI
61 select HAVE_ARCH_KMEMCHECK
62 select HAVE_USER_RETURN_NOTIFIER
63 select HAVE_ARCH_JUMP_LABEL
64 select HAVE_TEXT_POKE_SMP
65 select HAVE_GENERIC_HARDIRQS
66 select HAVE_SPARSE_IRQ
67 select GENERIC_FIND_FIRST_BIT
68 select GENERIC_FIND_NEXT_BIT
69 select GENERIC_IRQ_PROBE
70 select GENERIC_PENDING_IRQ if SMP
71 select GENERIC_IRQ_SHOW
72 select IRQ_FORCED_THREADING
73 select USE_GENERIC_SMP_HELPERS if SMP
74 select ARCH_NO_SYSDEV_OPS
76 config INSTRUCTION_DECODER
77 def_bool (KPROBES || PERF_EVENTS)
81 default "elf32-i386" if X86_32
82 default "elf64-x86-64" if X86_64
86 default "arch/x86/configs/i386_defconfig" if X86_32
87 default "arch/x86/configs/x86_64_defconfig" if X86_64
89 config GENERIC_CMOS_UPDATE
92 config CLOCKSOURCE_WATCHDOG
95 config GENERIC_CLOCKEVENTS
98 config GENERIC_CLOCKEVENTS_BROADCAST
100 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
102 config LOCKDEP_SUPPORT
105 config STACKTRACE_SUPPORT
108 config HAVE_LATENCYTOP_SUPPORT
120 config NEED_DMA_MAP_STATE
121 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
123 config NEED_SG_DMA_LENGTH
126 config GENERIC_ISA_DMA
135 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
137 config GENERIC_BUG_RELATIVE_POINTERS
140 config GENERIC_HWEIGHT
146 config ARCH_MAY_HAVE_PC_FDC
149 config RWSEM_GENERIC_SPINLOCK
152 config RWSEM_XCHGADD_ALGORITHM
155 config ARCH_HAS_CPU_IDLE_WAIT
158 config GENERIC_CALIBRATE_DELAY
161 config GENERIC_TIME_VSYSCALL
165 config ARCH_HAS_CPU_RELAX
168 config ARCH_HAS_DEFAULT_IDLE
171 config ARCH_HAS_CACHE_LINE_SIZE
174 config HAVE_SETUP_PER_CPU_AREA
177 config NEED_PER_CPU_EMBED_FIRST_CHUNK
180 config NEED_PER_CPU_PAGE_FIRST_CHUNK
183 config HAVE_CPUMASK_OF_CPU_MAP
186 config ARCH_HIBERNATION_POSSIBLE
189 config ARCH_SUSPEND_POSSIBLE
196 config ARCH_POPULATES_NODE_MAP
203 config ARCH_SUPPORTS_OPTIMIZED_INLINING
206 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
209 config HAVE_INTEL_TXT
211 depends on EXPERIMENTAL && DMAR && 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
237 config ARCH_CPU_PROBE_RELEASE
239 depends on HOTPLUG_CPU
241 source "init/Kconfig"
242 source "kernel/Kconfig.freezer"
244 menu "Processor type and features"
246 source "kernel/time/Kconfig"
249 bool "Symmetric multi-processing support"
251 This enables support for systems with more than one CPU. If you have
252 a system with only one CPU, like most personal computers, say N. If
253 you have a system with more than one CPU, say Y.
255 If you say N here, the kernel will run on single and multiprocessor
256 machines, but will use only one CPU of a multiprocessor machine. If
257 you say Y here, the kernel will run on many, but not all,
258 singleprocessor machines. On a singleprocessor machine, the kernel
259 will run faster if you say N here.
261 Note that if you say Y here and choose architecture "586" or
262 "Pentium" under "Processor family", the kernel will not work on 486
263 architectures. Similarly, multiprocessor kernels for the "PPro"
264 architecture may not work on all Pentium based boards.
266 People using multiprocessor machines who say Y here should also say
267 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
268 Management" code will be disabled if you say Y here.
270 See also <file:Documentation/i386/IO-APIC.txt>,
271 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
272 <http://www.tldp.org/docs.html#howto>.
274 If you don't know what to do here, say N.
277 bool "Support x2apic"
278 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
280 This enables x2apic support on CPUs that have this feature.
282 This allows 32-bit apic IDs (so it can support very large systems),
283 and accesses the local apic via MSRs not via mmio.
285 If you don't know what to do here, say N.
288 bool "Enable MPS table" if ACPI
290 depends on X86_LOCAL_APIC
292 For old smp systems that do not have proper acpi support. Newer systems
293 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
296 bool "Support for big SMP systems with more than 8 CPUs"
297 depends on X86_32 && SMP
299 This option is needed for the systems that have more than 8 CPUs
302 config X86_EXTENDED_PLATFORM
303 bool "Support for extended (non-PC) x86 platforms"
306 If you disable this option then the kernel will only support
307 standard PC platforms. (which covers the vast majority of
310 If you enable this option then you'll be able to select support
311 for the following (non-PC) 32 bit x86 platforms:
315 SGI 320/540 (Visual Workstation)
316 Summit/EXA (IBM x440)
317 Unisys ES7000 IA32 series
318 Moorestown MID devices
320 If you have one of these systems, or if you want to build a
321 generic distribution kernel, say Y here - otherwise say N.
325 config X86_EXTENDED_PLATFORM
326 bool "Support for extended (non-PC) x86 platforms"
329 If you disable this option then the kernel will only support
330 standard PC platforms. (which covers the vast majority of
333 If you enable this option then you'll be able to select support
334 for the following (non-PC) 64 bit x86 platforms:
338 If you have one of these systems, or if you want to build a
339 generic distribution kernel, say Y here - otherwise say N.
341 # This is an alphabetically sorted list of 64 bit extended platforms
342 # Please maintain the alphabetic order if and when there are additions
346 select PARAVIRT_GUEST
348 depends on X86_64 && PCI
349 depends on X86_EXTENDED_PLATFORM
351 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
352 supposed to run on these EM64T-based machines. Only choose this option
353 if you have one of these machines.
356 bool "SGI Ultraviolet"
358 depends on X86_EXTENDED_PLATFORM
360 depends on X86_X2APIC
362 This option is needed in order to support SGI Ultraviolet systems.
363 If you don't have one of these, you should say N here.
365 # Following is an alphabetically sorted list of 32 bit extended platforms
366 # Please maintain the alphabetic order if and when there are additions
371 depends on X86_EXTENDED_PLATFORM
373 Select this for an AMD Elan processor.
375 Do not use this option for K6/Athlon/Opteron processors!
377 If unsure, choose "PC-compatible" instead.
380 bool "CE4100 TV platform"
382 depends on PCI_GODIRECT
384 depends on X86_EXTENDED_PLATFORM
385 select X86_REBOOTFIXUPS
387 select OF_EARLY_FLATTREE
389 Select for the Intel CE media processor (CE4100) SOC.
390 This option compiles in support for the CE4100 SOC for settop
391 boxes and media devices.
394 bool "Moorestown MID platform"
398 depends on X86_EXTENDED_PLATFORM
399 depends on X86_IO_APIC
404 select X86_PLATFORM_DEVICES
406 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
407 Internet Device(MID) platform. Moorestown consists of two chips:
408 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
409 Unlike standard x86 PCs, Moorestown does not have many legacy devices
410 nor standard legacy replacement devices/features. e.g. Moorestown does
411 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
414 bool "RDC R-321x SoC"
416 depends on X86_EXTENDED_PLATFORM
418 select X86_REBOOTFIXUPS
420 This option is needed for RDC R-321x system-on-chip, also known
422 If you don't have one of these chips, you should say N here.
424 config X86_32_NON_STANDARD
425 bool "Support non-standard 32-bit SMP architectures"
426 depends on X86_32 && SMP
427 depends on X86_EXTENDED_PLATFORM
429 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
430 subarchitectures. It is intended for a generic binary kernel.
431 if you select them all, kernel will probe it one by one. and will
434 # Alphabetically sorted list of Non standard 32 bit platforms
437 bool "NUMAQ (IBM/Sequent)"
438 depends on X86_32_NON_STANDARD
443 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
444 NUMA multiquad box. This changes the way that processors are
445 bootstrapped, and uses Clustered Logical APIC addressing mode instead
446 of Flat Logical. You will need a new lynxer.elf file to flash your
447 firmware with - send email to <Martin.Bligh@us.ibm.com>.
449 config X86_SUPPORTS_MEMORY_FAILURE
451 # MCE code calls memory_failure():
453 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
454 depends on !X86_NUMAQ
455 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
456 depends on X86_64 || !SPARSEMEM
457 select ARCH_SUPPORTS_MEMORY_FAILURE
460 bool "SGI 320/540 (Visual Workstation)"
461 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
462 depends on X86_32_NON_STANDARD
464 The SGI Visual Workstation series is an IA32-based workstation
465 based on SGI systems chips with some legacy PC hardware attached.
467 Say Y here to create a kernel to run on the SGI 320 or 540.
469 A kernel compiled for the Visual Workstation will run on general
470 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
473 bool "Summit/EXA (IBM x440)"
474 depends on X86_32_NON_STANDARD
476 This option is needed for IBM systems that use the Summit/EXA chipset.
477 In particular, it is needed for the x440.
480 bool "Unisys ES7000 IA32 series"
481 depends on X86_32_NON_STANDARD && X86_BIGSMP
483 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
484 supposed to run on an IA32-based Unisys ES7000 system.
487 tristate "Eurobraille/Iris poweroff module"
490 The Iris machines from EuroBraille do not have APM or ACPI support
491 to shut themselves down properly. A special I/O sequence is
492 needed to do so, which is what this module does at
495 This is only for Iris machines from EuroBraille.
499 config SCHED_OMIT_FRAME_POINTER
501 prompt "Single-depth WCHAN output"
504 Calculate simpler /proc/<PID>/wchan values. If this option
505 is disabled then wchan values will recurse back to the
506 caller function. This provides more accurate wchan values,
507 at the expense of slightly more scheduling overhead.
509 If in doubt, say "Y".
511 menuconfig PARAVIRT_GUEST
512 bool "Paravirtualized guest support"
514 Say Y here to get to see options related to running Linux under
515 various hypervisors. This option alone does not add any kernel code.
517 If you say N, all options in this submenu will be skipped and disabled.
521 source "arch/x86/xen/Kconfig"
524 bool "KVM paravirtualized clock"
526 select PARAVIRT_CLOCK
528 Turning on this option will allow you to run a paravirtualized clock
529 when running over the KVM hypervisor. Instead of relying on a PIT
530 (or probably other) emulation by the underlying device model, the host
531 provides the guest with timing infrastructure such as time of day, and
535 bool "KVM Guest support"
538 This option enables various optimizations for running under the KVM
541 source "arch/x86/lguest/Kconfig"
544 bool "Enable paravirtualization code"
546 This changes the kernel so it can modify itself when it is run
547 under a hypervisor, potentially improving performance significantly
548 over full virtualization. However, when run without a hypervisor
549 the kernel is theoretically slower and slightly larger.
551 config PARAVIRT_SPINLOCKS
552 bool "Paravirtualization layer for spinlocks"
553 depends on PARAVIRT && SMP && EXPERIMENTAL
555 Paravirtualized spinlocks allow a pvops backend to replace the
556 spinlock implementation with something virtualization-friendly
557 (for example, block the virtual CPU rather than spinning).
559 Unfortunately the downside is an up to 5% performance hit on
560 native kernels, with various workloads.
562 If you are unsure how to answer this question, answer N.
564 config PARAVIRT_CLOCK
569 config PARAVIRT_DEBUG
570 bool "paravirt-ops debugging"
571 depends on PARAVIRT && DEBUG_KERNEL
573 Enable to debug paravirt_ops internals. Specifically, BUG if
574 a paravirt_op is missing when it is called.
582 This option adds a kernel parameter 'memtest', which allows memtest
584 memtest=0, mean disabled; -- default
585 memtest=1, mean do 1 test pattern;
587 memtest=4, mean do 4 test patterns.
588 If you are unsure how to answer this question, answer N.
590 config X86_SUMMIT_NUMA
592 depends on X86_32 && NUMA && X86_32_NON_STANDARD
594 config X86_CYCLONE_TIMER
596 depends on X86_32_NON_STANDARD
598 source "arch/x86/Kconfig.cpu"
602 prompt "HPET Timer Support" if X86_32
604 Use the IA-PC HPET (High Precision Event Timer) to manage
605 time in preference to the PIT and RTC, if a HPET is
607 HPET is the next generation timer replacing legacy 8254s.
608 The HPET provides a stable time base on SMP
609 systems, unlike the TSC, but it is more expensive to access,
610 as it is off-chip. You can find the HPET spec at
611 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
613 You can safely choose Y here. However, HPET will only be
614 activated if the platform and the BIOS support this feature.
615 Otherwise the 8254 will be used for timing services.
617 Choose N to continue using the legacy 8254 timer.
619 config HPET_EMULATE_RTC
621 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
625 prompt "Langwell APB Timer Support" if X86_MRST
627 APB timer is the replacement for 8254, HPET on X86 MID platforms.
628 The APBT provides a stable time base on SMP
629 systems, unlike the TSC, but it is more expensive to access,
630 as it is off-chip. APB timers are always running regardless of CPU
631 C states, they are used as per CPU clockevent device when possible.
633 # Mark as expert because too many people got it wrong.
634 # The code disables itself when not needed.
637 bool "Enable DMI scanning" if EXPERT
639 Enabled scanning of DMI to identify machine quirks. Say Y
640 here unless you have verified that your setup is not
641 affected by entries in the DMI blacklist. Required by PNP
645 bool "GART IOMMU support" if EXPERT
648 depends on X86_64 && PCI && AMD_NB
650 Support for full DMA access of devices with 32bit memory access only
651 on systems with more than 3GB. This is usually needed for USB,
652 sound, many IDE/SATA chipsets and some other devices.
653 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
654 based hardware IOMMU and a software bounce buffer based IOMMU used
655 on Intel systems and as fallback.
656 The code is only active when needed (enough memory and limited
657 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
661 bool "IBM Calgary IOMMU support"
663 depends on X86_64 && PCI && EXPERIMENTAL
665 Support for hardware IOMMUs in IBM's xSeries x366 and x460
666 systems. Needed to run systems with more than 3GB of memory
667 properly with 32-bit PCI devices that do not support DAC
668 (Double Address Cycle). Calgary also supports bus level
669 isolation, where all DMAs pass through the IOMMU. This
670 prevents them from going anywhere except their intended
671 destination. This catches hard-to-find kernel bugs and
672 mis-behaving drivers and devices that do not use the DMA-API
673 properly to set up their DMA buffers. The IOMMU can be
674 turned off at boot time with the iommu=off parameter.
675 Normally the kernel will make the right choice by itself.
678 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
680 prompt "Should Calgary be enabled by default?"
681 depends on CALGARY_IOMMU
683 Should Calgary be enabled by default? if you choose 'y', Calgary
684 will be used (if it exists). If you choose 'n', Calgary will not be
685 used even if it exists. If you choose 'n' and would like to use
686 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
690 bool "AMD IOMMU support"
693 depends on X86_64 && PCI && ACPI
695 With this option you can enable support for AMD IOMMU hardware in
696 your system. An IOMMU is a hardware component which provides
697 remapping of DMA memory accesses from devices. With an AMD IOMMU you
698 can isolate the the DMA memory of different devices and protect the
699 system from misbehaving device drivers or hardware.
701 You can find out if your system has an AMD IOMMU if you look into
702 your BIOS for an option to enable it or if you have an IVRS ACPI
705 config AMD_IOMMU_STATS
706 bool "Export AMD IOMMU statistics to debugfs"
710 This option enables code in the AMD IOMMU driver to collect various
711 statistics about whats happening in the driver and exports that
712 information to userspace via debugfs.
715 # need this always selected by IOMMU for the VIA workaround
719 Support for software bounce buffers used on x86-64 systems
720 which don't have a hardware IOMMU (e.g. the current generation
721 of Intel's x86-64 CPUs). Using this PCI devices which can only
722 access 32-bits of memory can be used on systems with more than
723 3 GB of memory. If unsure, say Y.
726 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
729 def_bool (AMD_IOMMU || DMAR)
732 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
733 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
734 select CPUMASK_OFFSTACK
736 Enable maximum number of CPUS and NUMA Nodes for this architecture.
740 int "Maximum number of CPUs" if SMP && !MAXSMP
741 range 2 8 if SMP && X86_32 && !X86_BIGSMP
742 range 2 512 if SMP && !MAXSMP
744 default "4096" if MAXSMP
745 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
748 This allows you to specify the maximum number of CPUs which this
749 kernel will support. The maximum supported value is 512 and the
750 minimum value which makes sense is 2.
752 This is purely to save memory - each supported CPU adds
753 approximately eight kilobytes to the kernel image.
756 bool "SMT (Hyperthreading) scheduler support"
759 SMT scheduler support improves the CPU scheduler's decision making
760 when dealing with Intel Pentium 4 chips with HyperThreading at a
761 cost of slightly increased overhead in some places. If unsure say
766 prompt "Multi-core scheduler support"
769 Multi-core scheduler support improves the CPU scheduler's decision
770 making when dealing with multi-core CPU chips at a cost of slightly
771 increased overhead in some places. If unsure say N here.
773 config IRQ_TIME_ACCOUNTING
774 bool "Fine granularity task level IRQ time accounting"
777 Select this option to enable fine granularity task irq time
778 accounting. This is done by reading a timestamp on each
779 transitions between softirq and hardirq state, so there can be a
780 small performance impact.
782 If in doubt, say N here.
784 source "kernel/Kconfig.preempt"
787 bool "Local APIC support on uniprocessors"
788 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
790 A local APIC (Advanced Programmable Interrupt Controller) is an
791 integrated interrupt controller in the CPU. If you have a single-CPU
792 system which has a processor with a local APIC, you can say Y here to
793 enable and use it. If you say Y here even though your machine doesn't
794 have a local APIC, then the kernel will still run with no slowdown at
795 all. The local APIC supports CPU-generated self-interrupts (timer,
796 performance counters), and the NMI watchdog which detects hard
800 bool "IO-APIC support on uniprocessors"
801 depends on X86_UP_APIC
803 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
804 SMP-capable replacement for PC-style interrupt controllers. Most
805 SMP systems and many recent uniprocessor systems have one.
807 If you have a single-CPU system with an IO-APIC, you can say Y here
808 to use it. If you say Y here even though your machine doesn't have
809 an IO-APIC, then the kernel will still run with no slowdown at all.
811 config X86_LOCAL_APIC
813 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
817 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
819 config X86_VISWS_APIC
821 depends on X86_32 && X86_VISWS
823 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
824 bool "Reroute for broken boot IRQs"
825 depends on X86_IO_APIC
827 This option enables a workaround that fixes a source of
828 spurious interrupts. This is recommended when threaded
829 interrupt handling is used on systems where the generation of
830 superfluous "boot interrupts" cannot be disabled.
832 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
833 entry in the chipset's IO-APIC is masked (as, e.g. the RT
834 kernel does during interrupt handling). On chipsets where this
835 boot IRQ generation cannot be disabled, this workaround keeps
836 the original IRQ line masked so that only the equivalent "boot
837 IRQ" is delivered to the CPUs. The workaround also tells the
838 kernel to set up the IRQ handler on the boot IRQ line. In this
839 way only one interrupt is delivered to the kernel. Otherwise
840 the spurious second interrupt may cause the kernel to bring
841 down (vital) interrupt lines.
843 Only affects "broken" chipsets. Interrupt sharing may be
844 increased on these systems.
847 bool "Machine Check / overheating reporting"
849 Machine Check support allows the processor to notify the
850 kernel if it detects a problem (e.g. overheating, data corruption).
851 The action the kernel takes depends on the severity of the problem,
852 ranging from warning messages to halting the machine.
856 prompt "Intel MCE features"
857 depends on X86_MCE && X86_LOCAL_APIC
859 Additional support for intel specific MCE features such as
864 prompt "AMD MCE features"
865 depends on X86_MCE && X86_LOCAL_APIC
867 Additional support for AMD specific MCE features such as
868 the DRAM Error Threshold.
870 config X86_ANCIENT_MCE
871 bool "Support for old Pentium 5 / WinChip machine checks"
872 depends on X86_32 && X86_MCE
874 Include support for machine check handling on old Pentium 5 or WinChip
875 systems. These typically need to be enabled explicitely on the command
878 config X86_MCE_THRESHOLD
879 depends on X86_MCE_AMD || X86_MCE_INTEL
882 config X86_MCE_INJECT
884 tristate "Machine check injector support"
886 Provide support for injecting machine checks for testing purposes.
887 If you don't know what a machine check is and you don't do kernel
888 QA it is safe to say n.
890 config X86_THERMAL_VECTOR
892 depends on X86_MCE_INTEL
895 bool "Enable VM86 support" if EXPERT
899 This option is required by programs like DOSEMU to run 16-bit legacy
900 code on X86 processors. It also may be needed by software like
901 XFree86 to initialize some video cards via BIOS. Disabling this
902 option saves about 6k.
905 tristate "Toshiba Laptop support"
908 This adds a driver to safely access the System Management Mode of
909 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
910 not work on models with a Phoenix BIOS. The System Management Mode
911 is used to set the BIOS and power saving options on Toshiba portables.
913 For information on utilities to make use of this driver see the
914 Toshiba Linux utilities web site at:
915 <http://www.buzzard.org.uk/toshiba/>.
917 Say Y if you intend to run this kernel on a Toshiba portable.
921 tristate "Dell laptop support"
923 This adds a driver to safely access the System Management Mode
924 of the CPU on the Dell Inspiron 8000. The System Management Mode
925 is used to read cpu temperature and cooling fan status and to
926 control the fans on the I8K portables.
928 This driver has been tested only on the Inspiron 8000 but it may
929 also work with other Dell laptops. You can force loading on other
930 models by passing the parameter `force=1' to the module. Use at
933 For information on utilities to make use of this driver see the
934 I8K Linux utilities web site at:
935 <http://people.debian.org/~dz/i8k/>
937 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
940 config X86_REBOOTFIXUPS
941 bool "Enable X86 board specific fixups for reboot"
944 This enables chipset and/or board specific fixups to be done
945 in order to get reboot to work correctly. This is only needed on
946 some combinations of hardware and BIOS. The symptom, for which
947 this config is intended, is when reboot ends with a stalled/hung
950 Currently, the only fixup is for the Geode machines using
951 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
953 Say Y if you want to enable the fixup. Currently, it's safe to
954 enable this option even if you don't need it.
958 tristate "/dev/cpu/microcode - microcode support"
961 If you say Y here, you will be able to update the microcode on
962 certain Intel and AMD processors. The Intel support is for the
963 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
964 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
965 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
966 You will obviously need the actual microcode binary data itself
967 which is not shipped with the Linux kernel.
969 This option selects the general module only, you need to select
970 at least one vendor specific module as well.
972 To compile this driver as a module, choose M here: the
973 module will be called microcode.
975 config MICROCODE_INTEL
976 bool "Intel microcode patch loading support"
981 This options enables microcode patch loading support for Intel
984 For latest news and information on obtaining all the required
985 Intel ingredients for this driver, check:
986 <http://www.urbanmyth.org/microcode/>.
989 bool "AMD microcode patch loading support"
993 If you select this option, microcode patch loading support for AMD
994 processors will be enabled.
996 config MICROCODE_OLD_INTERFACE
1001 tristate "/dev/cpu/*/msr - Model-specific register support"
1003 This device gives privileged processes access to the x86
1004 Model-Specific Registers (MSRs). It is a character device with
1005 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1006 MSR accesses are directed to a specific CPU on multi-processor
1010 tristate "/dev/cpu/*/cpuid - CPU information support"
1012 This device gives processes access to the x86 CPUID instruction to
1013 be executed on a specific processor. It is a character device
1014 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1018 prompt "High Memory Support"
1019 default HIGHMEM64G if X86_NUMAQ
1025 depends on !X86_NUMAQ
1027 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1028 However, the address space of 32-bit x86 processors is only 4
1029 Gigabytes large. That means that, if you have a large amount of
1030 physical memory, not all of it can be "permanently mapped" by the
1031 kernel. The physical memory that's not permanently mapped is called
1034 If you are compiling a kernel which will never run on a machine with
1035 more than 1 Gigabyte total physical RAM, answer "off" here (default
1036 choice and suitable for most users). This will result in a "3GB/1GB"
1037 split: 3GB are mapped so that each process sees a 3GB virtual memory
1038 space and the remaining part of the 4GB virtual memory space is used
1039 by the kernel to permanently map as much physical memory as
1042 If the machine has between 1 and 4 Gigabytes physical RAM, then
1045 If more than 4 Gigabytes is used then answer "64GB" here. This
1046 selection turns Intel PAE (Physical Address Extension) mode on.
1047 PAE implements 3-level paging on IA32 processors. PAE is fully
1048 supported by Linux, PAE mode is implemented on all recent Intel
1049 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1050 then the kernel will not boot on CPUs that don't support PAE!
1052 The actual amount of total physical memory will either be
1053 auto detected or can be forced by using a kernel command line option
1054 such as "mem=256M". (Try "man bootparam" or see the documentation of
1055 your boot loader (lilo or loadlin) about how to pass options to the
1056 kernel at boot time.)
1058 If unsure, say "off".
1062 depends on !X86_NUMAQ
1064 Select this if you have a 32-bit processor and between 1 and 4
1065 gigabytes of physical RAM.
1069 depends on !M386 && !M486
1072 Select this if you have a 32-bit processor and more than 4
1073 gigabytes of physical RAM.
1078 depends on EXPERIMENTAL
1079 prompt "Memory split" if EXPERT
1083 Select the desired split between kernel and user memory.
1085 If the address range available to the kernel is less than the
1086 physical memory installed, the remaining memory will be available
1087 as "high memory". Accessing high memory is a little more costly
1088 than low memory, as it needs to be mapped into the kernel first.
1089 Note that increasing the kernel address space limits the range
1090 available to user programs, making the address space there
1091 tighter. Selecting anything other than the default 3G/1G split
1092 will also likely make your kernel incompatible with binary-only
1095 If you are not absolutely sure what you are doing, leave this
1099 bool "3G/1G user/kernel split"
1100 config VMSPLIT_3G_OPT
1102 bool "3G/1G user/kernel split (for full 1G low memory)"
1104 bool "2G/2G user/kernel split"
1105 config VMSPLIT_2G_OPT
1107 bool "2G/2G user/kernel split (for full 2G low memory)"
1109 bool "1G/3G user/kernel split"
1114 default 0xB0000000 if VMSPLIT_3G_OPT
1115 default 0x80000000 if VMSPLIT_2G
1116 default 0x78000000 if VMSPLIT_2G_OPT
1117 default 0x40000000 if VMSPLIT_1G
1123 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1126 bool "PAE (Physical Address Extension) Support"
1127 depends on X86_32 && !HIGHMEM4G
1129 PAE is required for NX support, and furthermore enables
1130 larger swapspace support for non-overcommit purposes. It
1131 has the cost of more pagetable lookup overhead, and also
1132 consumes more pagetable space per process.
1134 config ARCH_PHYS_ADDR_T_64BIT
1135 def_bool X86_64 || X86_PAE
1137 config ARCH_DMA_ADDR_T_64BIT
1138 def_bool X86_64 || HIGHMEM64G
1140 config DIRECT_GBPAGES
1141 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1145 Allow the kernel linear mapping to use 1GB pages on CPUs that
1146 support it. This can improve the kernel's performance a tiny bit by
1147 reducing TLB pressure. If in doubt, say "Y".
1149 # Common NUMA Features
1151 bool "Numa Memory Allocation and Scheduler Support"
1153 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1154 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1156 Enable NUMA (Non Uniform Memory Access) support.
1158 The kernel will try to allocate memory used by a CPU on the
1159 local memory controller of the CPU and add some more
1160 NUMA awareness to the kernel.
1162 For 64-bit this is recommended if the system is Intel Core i7
1163 (or later), AMD Opteron, or EM64T NUMA.
1165 For 32-bit this is only needed on (rare) 32-bit-only platforms
1166 that support NUMA topologies, such as NUMAQ / Summit, or if you
1167 boot a 32-bit kernel on a 64-bit NUMA platform.
1169 Otherwise, you should say N.
1171 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1172 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1176 prompt "Old style AMD Opteron NUMA detection"
1177 depends on X86_64 && NUMA && PCI
1179 Enable AMD NUMA node topology detection. You should say Y here if
1180 you have a multi processor AMD system. This uses an old method to
1181 read the NUMA configuration directly from the builtin Northbridge
1182 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1183 which also takes priority if both are compiled in.
1185 config X86_64_ACPI_NUMA
1187 prompt "ACPI NUMA detection"
1188 depends on X86_64 && NUMA && ACPI && PCI
1191 Enable ACPI SRAT based node topology detection.
1193 # Some NUMA nodes have memory ranges that span
1194 # other nodes. Even though a pfn is valid and
1195 # between a node's start and end pfns, it may not
1196 # reside on that node. See memmap_init_zone()
1198 config NODES_SPAN_OTHER_NODES
1200 depends on X86_64_ACPI_NUMA
1203 bool "NUMA emulation"
1204 depends on X86_64 && NUMA
1206 Enable NUMA emulation. A flat machine will be split
1207 into virtual nodes when booted with "numa=fake=N", where N is the
1208 number of nodes. This is only useful for debugging.
1211 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1213 default "10" if MAXSMP
1214 default "6" if X86_64
1215 default "4" if X86_NUMAQ
1217 depends on NEED_MULTIPLE_NODES
1219 Specify the maximum number of NUMA Nodes available on the target
1220 system. Increases memory reserved to accommodate various tables.
1222 config HAVE_ARCH_BOOTMEM
1224 depends on X86_32 && NUMA
1226 config ARCH_HAVE_MEMORY_PRESENT
1228 depends on X86_32 && DISCONTIGMEM
1230 config NEED_NODE_MEMMAP_SIZE
1232 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1234 config HAVE_ARCH_ALLOC_REMAP
1236 depends on X86_32 && NUMA
1238 config ARCH_FLATMEM_ENABLE
1240 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1242 config ARCH_DISCONTIGMEM_ENABLE
1244 depends on NUMA && X86_32
1246 config ARCH_DISCONTIGMEM_DEFAULT
1248 depends on NUMA && X86_32
1250 config ARCH_PROC_KCORE_TEXT
1252 depends on X86_64 && PROC_KCORE
1254 config ARCH_SPARSEMEM_DEFAULT
1258 config ARCH_SPARSEMEM_ENABLE
1260 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1261 select SPARSEMEM_STATIC if X86_32
1262 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1264 config ARCH_SELECT_MEMORY_MODEL
1266 depends on ARCH_SPARSEMEM_ENABLE
1268 config ARCH_MEMORY_PROBE
1270 depends on MEMORY_HOTPLUG
1272 config ILLEGAL_POINTER_VALUE
1275 default 0xdead000000000000 if X86_64
1280 bool "Allocate 3rd-level pagetables from highmem"
1283 The VM uses one page table entry for each page of physical memory.
1284 For systems with a lot of RAM, this can be wasteful of precious
1285 low memory. Setting this option will put user-space page table
1286 entries in high memory.
1288 config X86_CHECK_BIOS_CORRUPTION
1289 bool "Check for low memory corruption"
1291 Periodically check for memory corruption in low memory, which
1292 is suspected to be caused by BIOS. Even when enabled in the
1293 configuration, it is disabled at runtime. Enable it by
1294 setting "memory_corruption_check=1" on the kernel command
1295 line. By default it scans the low 64k of memory every 60
1296 seconds; see the memory_corruption_check_size and
1297 memory_corruption_check_period parameters in
1298 Documentation/kernel-parameters.txt to adjust this.
1300 When enabled with the default parameters, this option has
1301 almost no overhead, as it reserves a relatively small amount
1302 of memory and scans it infrequently. It both detects corruption
1303 and prevents it from affecting the running system.
1305 It is, however, intended as a diagnostic tool; if repeatable
1306 BIOS-originated corruption always affects the same memory,
1307 you can use memmap= to prevent the kernel from using that
1310 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1311 bool "Set the default setting of memory_corruption_check"
1312 depends on X86_CHECK_BIOS_CORRUPTION
1315 Set whether the default state of memory_corruption_check is
1318 config X86_RESERVE_LOW
1319 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1323 Specify the amount of low memory to reserve for the BIOS.
1325 The first page contains BIOS data structures that the kernel
1326 must not use, so that page must always be reserved.
1328 By default we reserve the first 64K of physical RAM, as a
1329 number of BIOSes are known to corrupt that memory range
1330 during events such as suspend/resume or monitor cable
1331 insertion, so it must not be used by the kernel.
1333 You can set this to 4 if you are absolutely sure that you
1334 trust the BIOS to get all its memory reservations and usages
1335 right. If you know your BIOS have problems beyond the
1336 default 64K area, you can set this to 640 to avoid using the
1337 entire low memory range.
1339 If you have doubts about the BIOS (e.g. suspend/resume does
1340 not work or there's kernel crashes after certain hardware
1341 hotplug events) then you might want to enable
1342 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1343 typical corruption patterns.
1345 Leave this to the default value of 64 if you are unsure.
1347 config MATH_EMULATION
1349 prompt "Math emulation" if X86_32
1351 Linux can emulate a math coprocessor (used for floating point
1352 operations) if you don't have one. 486DX and Pentium processors have
1353 a math coprocessor built in, 486SX and 386 do not, unless you added
1354 a 487DX or 387, respectively. (The messages during boot time can
1355 give you some hints here ["man dmesg"].) Everyone needs either a
1356 coprocessor or this emulation.
1358 If you don't have a math coprocessor, you need to say Y here; if you
1359 say Y here even though you have a coprocessor, the coprocessor will
1360 be used nevertheless. (This behavior can be changed with the kernel
1361 command line option "no387", which comes handy if your coprocessor
1362 is broken. Try "man bootparam" or see the documentation of your boot
1363 loader (lilo or loadlin) about how to pass options to the kernel at
1364 boot time.) This means that it is a good idea to say Y here if you
1365 intend to use this kernel on different machines.
1367 More information about the internals of the Linux math coprocessor
1368 emulation can be found in <file:arch/x86/math-emu/README>.
1370 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1371 kernel, it won't hurt.
1375 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1377 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1378 the Memory Type Range Registers (MTRRs) may be used to control
1379 processor access to memory ranges. This is most useful if you have
1380 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1381 allows bus write transfers to be combined into a larger transfer
1382 before bursting over the PCI/AGP bus. This can increase performance
1383 of image write operations 2.5 times or more. Saying Y here creates a
1384 /proc/mtrr file which may be used to manipulate your processor's
1385 MTRRs. Typically the X server should use this.
1387 This code has a reasonably generic interface so that similar
1388 control registers on other processors can be easily supported
1391 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1392 Registers (ARRs) which provide a similar functionality to MTRRs. For
1393 these, the ARRs are used to emulate the MTRRs.
1394 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1395 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1396 write-combining. All of these processors are supported by this code
1397 and it makes sense to say Y here if you have one of them.
1399 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1400 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1401 can lead to all sorts of problems, so it's good to say Y here.
1403 You can safely say Y even if your machine doesn't have MTRRs, you'll
1404 just add about 9 KB to your kernel.
1406 See <file:Documentation/x86/mtrr.txt> for more information.
1408 config MTRR_SANITIZER
1410 prompt "MTRR cleanup support"
1413 Convert MTRR layout from continuous to discrete, so X drivers can
1414 add writeback entries.
1416 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1417 The largest mtrr entry size for a continuous block can be set with
1422 config MTRR_SANITIZER_ENABLE_DEFAULT
1423 int "MTRR cleanup enable value (0-1)"
1426 depends on MTRR_SANITIZER
1428 Enable mtrr cleanup default value
1430 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1431 int "MTRR cleanup spare reg num (0-7)"
1434 depends on MTRR_SANITIZER
1436 mtrr cleanup spare entries default, it can be changed via
1437 mtrr_spare_reg_nr=N on the kernel command line.
1441 prompt "x86 PAT support" if EXPERT
1444 Use PAT attributes to setup page level cache control.
1446 PATs are the modern equivalents of MTRRs and are much more
1447 flexible than MTRRs.
1449 Say N here if you see bootup problems (boot crash, boot hang,
1450 spontaneous reboots) or a non-working video driver.
1454 config ARCH_USES_PG_UNCACHED
1459 bool "EFI runtime service support"
1462 This enables the kernel to use EFI runtime services that are
1463 available (such as the EFI variable services).
1465 This option is only useful on systems that have EFI firmware.
1466 In addition, you should use the latest ELILO loader available
1467 at <http://elilo.sourceforge.net> in order to take advantage
1468 of EFI runtime services. However, even with this option, the
1469 resultant kernel should continue to boot on existing non-EFI
1474 prompt "Enable seccomp to safely compute untrusted bytecode"
1476 This kernel feature is useful for number crunching applications
1477 that may need to compute untrusted bytecode during their
1478 execution. By using pipes or other transports made available to
1479 the process as file descriptors supporting the read/write
1480 syscalls, it's possible to isolate those applications in
1481 their own address space using seccomp. Once seccomp is
1482 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1483 and the task is only allowed to execute a few safe syscalls
1484 defined by each seccomp mode.
1486 If unsure, say Y. Only embedded should say N here.
1488 config CC_STACKPROTECTOR
1489 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1491 This option turns on the -fstack-protector GCC feature. This
1492 feature puts, at the beginning of functions, a canary value on
1493 the stack just before the return address, and validates
1494 the value just before actually returning. Stack based buffer
1495 overflows (that need to overwrite this return address) now also
1496 overwrite the canary, which gets detected and the attack is then
1497 neutralized via a kernel panic.
1499 This feature requires gcc version 4.2 or above, or a distribution
1500 gcc with the feature backported. Older versions are automatically
1501 detected and for those versions, this configuration option is
1502 ignored. (and a warning is printed during bootup)
1504 source kernel/Kconfig.hz
1507 bool "kexec system call"
1509 kexec is a system call that implements the ability to shutdown your
1510 current kernel, and to start another kernel. It is like a reboot
1511 but it is independent of the system firmware. And like a reboot
1512 you can start any kernel with it, not just Linux.
1514 The name comes from the similarity to the exec system call.
1516 It is an ongoing process to be certain the hardware in a machine
1517 is properly shutdown, so do not be surprised if this code does not
1518 initially work for you. It may help to enable device hotplugging
1519 support. As of this writing the exact hardware interface is
1520 strongly in flux, so no good recommendation can be made.
1523 bool "kernel crash dumps"
1524 depends on X86_64 || (X86_32 && HIGHMEM)
1526 Generate crash dump after being started by kexec.
1527 This should be normally only set in special crash dump kernels
1528 which are loaded in the main kernel with kexec-tools into
1529 a specially reserved region and then later executed after
1530 a crash by kdump/kexec. The crash dump kernel must be compiled
1531 to a memory address not used by the main kernel or BIOS using
1532 PHYSICAL_START, or it must be built as a relocatable image
1533 (CONFIG_RELOCATABLE=y).
1534 For more details see Documentation/kdump/kdump.txt
1537 bool "kexec jump (EXPERIMENTAL)"
1538 depends on EXPERIMENTAL
1539 depends on KEXEC && HIBERNATION
1541 Jump between original kernel and kexeced kernel and invoke
1542 code in physical address mode via KEXEC
1544 config PHYSICAL_START
1545 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1548 This gives the physical address where the kernel is loaded.
1550 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1551 bzImage will decompress itself to above physical address and
1552 run from there. Otherwise, bzImage will run from the address where
1553 it has been loaded by the boot loader and will ignore above physical
1556 In normal kdump cases one does not have to set/change this option
1557 as now bzImage can be compiled as a completely relocatable image
1558 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1559 address. This option is mainly useful for the folks who don't want
1560 to use a bzImage for capturing the crash dump and want to use a
1561 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1562 to be specifically compiled to run from a specific memory area
1563 (normally a reserved region) and this option comes handy.
1565 So if you are using bzImage for capturing the crash dump,
1566 leave the value here unchanged to 0x1000000 and set
1567 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1568 for capturing the crash dump change this value to start of
1569 the reserved region. In other words, it can be set based on
1570 the "X" value as specified in the "crashkernel=YM@XM"
1571 command line boot parameter passed to the panic-ed
1572 kernel. Please take a look at Documentation/kdump/kdump.txt
1573 for more details about crash dumps.
1575 Usage of bzImage for capturing the crash dump is recommended as
1576 one does not have to build two kernels. Same kernel can be used
1577 as production kernel and capture kernel. Above option should have
1578 gone away after relocatable bzImage support is introduced. But it
1579 is present because there are users out there who continue to use
1580 vmlinux for dump capture. This option should go away down the
1583 Don't change this unless you know what you are doing.
1586 bool "Build a relocatable kernel"
1589 This builds a kernel image that retains relocation information
1590 so it can be loaded someplace besides the default 1MB.
1591 The relocations tend to make the kernel binary about 10% larger,
1592 but are discarded at runtime.
1594 One use is for the kexec on panic case where the recovery kernel
1595 must live at a different physical address than the primary
1598 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1599 it has been loaded at and the compile time physical address
1600 (CONFIG_PHYSICAL_START) is ignored.
1602 # Relocation on x86-32 needs some additional build support
1603 config X86_NEED_RELOCS
1605 depends on X86_32 && RELOCATABLE
1607 config PHYSICAL_ALIGN
1608 hex "Alignment value to which kernel should be aligned" if X86_32
1610 range 0x2000 0x1000000
1612 This value puts the alignment restrictions on physical address
1613 where kernel is loaded and run from. Kernel is compiled for an
1614 address which meets above alignment restriction.
1616 If bootloader loads the kernel at a non-aligned address and
1617 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1618 address aligned to above value and run from there.
1620 If bootloader loads the kernel at a non-aligned address and
1621 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1622 load address and decompress itself to the address it has been
1623 compiled for and run from there. The address for which kernel is
1624 compiled already meets above alignment restrictions. Hence the
1625 end result is that kernel runs from a physical address meeting
1626 above alignment restrictions.
1628 Don't change this unless you know what you are doing.
1631 bool "Support for hot-pluggable CPUs"
1632 depends on SMP && HOTPLUG
1634 Say Y here to allow turning CPUs off and on. CPUs can be
1635 controlled through /sys/devices/system/cpu.
1636 ( Note: power management support will enable this option
1637 automatically on SMP systems. )
1638 Say N if you want to disable CPU hotplug.
1642 prompt "Compat VDSO support"
1643 depends on X86_32 || IA32_EMULATION
1645 Map the 32-bit VDSO to the predictable old-style address too.
1647 Say N here if you are running a sufficiently recent glibc
1648 version (2.3.3 or later), to remove the high-mapped
1649 VDSO mapping and to exclusively use the randomized VDSO.
1654 bool "Built-in kernel command line"
1656 Allow for specifying boot arguments to the kernel at
1657 build time. On some systems (e.g. embedded ones), it is
1658 necessary or convenient to provide some or all of the
1659 kernel boot arguments with the kernel itself (that is,
1660 to not rely on the boot loader to provide them.)
1662 To compile command line arguments into the kernel,
1663 set this option to 'Y', then fill in the
1664 the boot arguments in CONFIG_CMDLINE.
1666 Systems with fully functional boot loaders (i.e. non-embedded)
1667 should leave this option set to 'N'.
1670 string "Built-in kernel command string"
1671 depends on CMDLINE_BOOL
1674 Enter arguments here that should be compiled into the kernel
1675 image and used at boot time. If the boot loader provides a
1676 command line at boot time, it is appended to this string to
1677 form the full kernel command line, when the system boots.
1679 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1680 change this behavior.
1682 In most cases, the command line (whether built-in or provided
1683 by the boot loader) should specify the device for the root
1686 config CMDLINE_OVERRIDE
1687 bool "Built-in command line overrides boot loader arguments"
1688 depends on CMDLINE_BOOL
1690 Set this option to 'Y' to have the kernel ignore the boot loader
1691 command line, and use ONLY the built-in command line.
1693 This is used to work around broken boot loaders. This should
1694 be set to 'N' under normal conditions.
1698 config ARCH_ENABLE_MEMORY_HOTPLUG
1700 depends on X86_64 || (X86_32 && HIGHMEM)
1702 config ARCH_ENABLE_MEMORY_HOTREMOVE
1704 depends on MEMORY_HOTPLUG
1706 config HAVE_ARCH_EARLY_PFN_TO_NID
1710 config USE_PERCPU_NUMA_NODE_ID
1714 menu "Power management and ACPI options"
1716 config ARCH_HIBERNATION_HEADER
1718 depends on X86_64 && HIBERNATION
1720 source "kernel/power/Kconfig"
1722 source "drivers/acpi/Kconfig"
1724 source "drivers/sfi/Kconfig"
1728 depends on APM || APM_MODULE
1731 tristate "APM (Advanced Power Management) BIOS support"
1732 depends on X86_32 && PM_SLEEP
1734 APM is a BIOS specification for saving power using several different
1735 techniques. This is mostly useful for battery powered laptops with
1736 APM compliant BIOSes. If you say Y here, the system time will be
1737 reset after a RESUME operation, the /proc/apm device will provide
1738 battery status information, and user-space programs will receive
1739 notification of APM "events" (e.g. battery status change).
1741 If you select "Y" here, you can disable actual use of the APM
1742 BIOS by passing the "apm=off" option to the kernel at boot time.
1744 Note that the APM support is almost completely disabled for
1745 machines with more than one CPU.
1747 In order to use APM, you will need supporting software. For location
1748 and more information, read <file:Documentation/power/pm.txt> and the
1749 Battery Powered Linux mini-HOWTO, available from
1750 <http://www.tldp.org/docs.html#howto>.
1752 This driver does not spin down disk drives (see the hdparm(8)
1753 manpage ("man 8 hdparm") for that), and it doesn't turn off
1754 VESA-compliant "green" monitors.
1756 This driver does not support the TI 4000M TravelMate and the ACER
1757 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1758 desktop machines also don't have compliant BIOSes, and this driver
1759 may cause those machines to panic during the boot phase.
1761 Generally, if you don't have a battery in your machine, there isn't
1762 much point in using this driver and you should say N. If you get
1763 random kernel OOPSes or reboots that don't seem to be related to
1764 anything, try disabling/enabling this option (or disabling/enabling
1767 Some other things you should try when experiencing seemingly random,
1770 1) make sure that you have enough swap space and that it is
1772 2) pass the "no-hlt" option to the kernel
1773 3) switch on floating point emulation in the kernel and pass
1774 the "no387" option to the kernel
1775 4) pass the "floppy=nodma" option to the kernel
1776 5) pass the "mem=4M" option to the kernel (thereby disabling
1777 all but the first 4 MB of RAM)
1778 6) make sure that the CPU is not over clocked.
1779 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1780 8) disable the cache from your BIOS settings
1781 9) install a fan for the video card or exchange video RAM
1782 10) install a better fan for the CPU
1783 11) exchange RAM chips
1784 12) exchange the motherboard.
1786 To compile this driver as a module, choose M here: the
1787 module will be called apm.
1791 config APM_IGNORE_USER_SUSPEND
1792 bool "Ignore USER SUSPEND"
1794 This option will ignore USER SUSPEND requests. On machines with a
1795 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1796 series notebooks, it is necessary to say Y because of a BIOS bug.
1798 config APM_DO_ENABLE
1799 bool "Enable PM at boot time"
1801 Enable APM features at boot time. From page 36 of the APM BIOS
1802 specification: "When disabled, the APM BIOS does not automatically
1803 power manage devices, enter the Standby State, enter the Suspend
1804 State, or take power saving steps in response to CPU Idle calls."
1805 This driver will make CPU Idle calls when Linux is idle (unless this
1806 feature is turned off -- see "Do CPU IDLE calls", below). This
1807 should always save battery power, but more complicated APM features
1808 will be dependent on your BIOS implementation. You may need to turn
1809 this option off if your computer hangs at boot time when using APM
1810 support, or if it beeps continuously instead of suspending. Turn
1811 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1812 T400CDT. This is off by default since most machines do fine without
1816 bool "Make CPU Idle calls when idle"
1818 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1819 On some machines, this can activate improved power savings, such as
1820 a slowed CPU clock rate, when the machine is idle. These idle calls
1821 are made after the idle loop has run for some length of time (e.g.,
1822 333 mS). On some machines, this will cause a hang at boot time or
1823 whenever the CPU becomes idle. (On machines with more than one CPU,
1824 this option does nothing.)
1826 config APM_DISPLAY_BLANK
1827 bool "Enable console blanking using APM"
1829 Enable console blanking using the APM. Some laptops can use this to
1830 turn off the LCD backlight when the screen blanker of the Linux
1831 virtual console blanks the screen. Note that this is only used by
1832 the virtual console screen blanker, and won't turn off the backlight
1833 when using the X Window system. This also doesn't have anything to
1834 do with your VESA-compliant power-saving monitor. Further, this
1835 option doesn't work for all laptops -- it might not turn off your
1836 backlight at all, or it might print a lot of errors to the console,
1837 especially if you are using gpm.
1839 config APM_ALLOW_INTS
1840 bool "Allow interrupts during APM BIOS calls"
1842 Normally we disable external interrupts while we are making calls to
1843 the APM BIOS as a measure to lessen the effects of a badly behaving
1844 BIOS implementation. The BIOS should reenable interrupts if it
1845 needs to. Unfortunately, some BIOSes do not -- especially those in
1846 many of the newer IBM Thinkpads. If you experience hangs when you
1847 suspend, try setting this to Y. Otherwise, say N.
1851 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1853 source "drivers/cpuidle/Kconfig"
1855 source "drivers/idle/Kconfig"
1860 menu "Bus options (PCI etc.)"
1865 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1867 Find out whether you have a PCI motherboard. PCI is the name of a
1868 bus system, i.e. the way the CPU talks to the other stuff inside
1869 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1870 VESA. If you have PCI, say Y, otherwise N.
1873 prompt "PCI access mode"
1874 depends on X86_32 && PCI
1877 On PCI systems, the BIOS can be used to detect the PCI devices and
1878 determine their configuration. However, some old PCI motherboards
1879 have BIOS bugs and may crash if this is done. Also, some embedded
1880 PCI-based systems don't have any BIOS at all. Linux can also try to
1881 detect the PCI hardware directly without using the BIOS.
1883 With this option, you can specify how Linux should detect the
1884 PCI devices. If you choose "BIOS", the BIOS will be used,
1885 if you choose "Direct", the BIOS won't be used, and if you
1886 choose "MMConfig", then PCI Express MMCONFIG will be used.
1887 If you choose "Any", the kernel will try MMCONFIG, then the
1888 direct access method and falls back to the BIOS if that doesn't
1889 work. If unsure, go with the default, which is "Any".
1894 config PCI_GOMMCONFIG
1911 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1913 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1916 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1920 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1924 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1928 depends on PCI && XEN
1936 bool "Support mmconfig PCI config space access"
1937 depends on X86_64 && PCI && ACPI
1939 config PCI_CNB20LE_QUIRK
1940 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1942 depends on PCI && EXPERIMENTAL
1944 Read the PCI windows out of the CNB20LE host bridge. This allows
1945 PCI hotplug to work on systems with the CNB20LE chipset which do
1948 There's no public spec for this chipset, and this functionality
1949 is known to be incomplete.
1951 You should say N unless you know you need this.
1954 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1955 depends on PCI_MSI && ACPI && EXPERIMENTAL
1957 DMA remapping (DMAR) devices support enables independent address
1958 translations for Direct Memory Access (DMA) from devices.
1959 These DMA remapping devices are reported via ACPI tables
1960 and include PCI device scope covered by these DMA
1963 config DMAR_DEFAULT_ON
1965 prompt "Enable DMA Remapping Devices by default"
1968 Selecting this option will enable a DMAR device at boot time if
1969 one is found. If this option is not selected, DMAR support can
1970 be enabled by passing intel_iommu=on to the kernel. It is
1971 recommended you say N here while the DMAR code remains
1974 config DMAR_BROKEN_GFX_WA
1975 bool "Workaround broken graphics drivers (going away soon)"
1976 depends on DMAR && BROKEN
1978 Current Graphics drivers tend to use physical address
1979 for DMA and avoid using DMA APIs. Setting this config
1980 option permits the IOMMU driver to set a unity map for
1981 all the OS-visible memory. Hence the driver can continue
1982 to use physical addresses for DMA, at least until this
1983 option is removed in the 2.6.32 kernel.
1985 config DMAR_FLOPPY_WA
1989 Floppy disk drivers are known to bypass DMA API calls
1990 thereby failing to work when IOMMU is enabled. This
1991 workaround will setup a 1:1 mapping for the first
1992 16MiB to make floppy (an ISA device) work.
1995 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1996 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1998 Supports Interrupt remapping for IO-APIC and MSI devices.
1999 To use x2apic mode in the CPU's which support x2APIC enhancements or
2000 to support platforms with CPU's having > 8 bit APIC ID, say Y.
2002 source "drivers/pci/pcie/Kconfig"
2004 source "drivers/pci/Kconfig"
2006 # x86_64 have no ISA slots, but can have ISA-style DMA.
2008 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2011 Enables ISA-style DMA support for devices requiring such controllers.
2019 Find out whether you have ISA slots on your motherboard. ISA is the
2020 name of a bus system, i.e. the way the CPU talks to the other stuff
2021 inside your box. Other bus systems are PCI, EISA, MicroChannel
2022 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2023 newer boards don't support it. If you have ISA, say Y, otherwise N.
2029 The Extended Industry Standard Architecture (EISA) bus was
2030 developed as an open alternative to the IBM MicroChannel bus.
2032 The EISA bus provided some of the features of the IBM MicroChannel
2033 bus while maintaining backward compatibility with cards made for
2034 the older ISA bus. The EISA bus saw limited use between 1988 and
2035 1995 when it was made obsolete by the PCI bus.
2037 Say Y here if you are building a kernel for an EISA-based machine.
2041 source "drivers/eisa/Kconfig"
2046 MicroChannel Architecture is found in some IBM PS/2 machines and
2047 laptops. It is a bus system similar to PCI or ISA. See
2048 <file:Documentation/mca.txt> (and especially the web page given
2049 there) before attempting to build an MCA bus kernel.
2051 source "drivers/mca/Kconfig"
2054 tristate "NatSemi SCx200 support"
2056 This provides basic support for National Semiconductor's
2057 (now AMD's) Geode processors. The driver probes for the
2058 PCI-IDs of several on-chip devices, so its a good dependency
2059 for other scx200_* drivers.
2061 If compiled as a module, the driver is named scx200.
2063 config SCx200HR_TIMER
2064 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2068 This driver provides a clocksource built upon the on-chip
2069 27MHz high-resolution timer. Its also a workaround for
2070 NSC Geode SC-1100's buggy TSC, which loses time when the
2071 processor goes idle (as is done by the scheduler). The
2072 other workaround is idle=poll boot option.
2075 bool "One Laptop Per Child support"
2079 select OF_PROMTREE if PROC_DEVICETREE
2081 Add support for detecting the unique features of the OLPC
2085 tristate "OLPC XO-1 support"
2086 depends on OLPC && MFD_CS5535
2088 Add support for non-essential features of the OLPC XO-1 laptop.
2094 depends on CPU_SUP_AMD && PCI
2096 source "drivers/pcmcia/Kconfig"
2098 source "drivers/pci/hotplug/Kconfig"
2101 bool "RapidIO support"
2105 If you say Y here, the kernel will include drivers and
2106 infrastructure code to support RapidIO interconnect devices.
2108 source "drivers/rapidio/Kconfig"
2113 menu "Executable file formats / Emulations"
2115 source "fs/Kconfig.binfmt"
2117 config IA32_EMULATION
2118 bool "IA32 Emulation"
2120 select COMPAT_BINFMT_ELF
2122 Include code to run 32-bit programs under a 64-bit kernel. You should
2123 likely turn this on, unless you're 100% sure that you don't have any
2124 32-bit programs left.
2127 tristate "IA32 a.out support"
2128 depends on IA32_EMULATION
2130 Support old a.out binaries in the 32bit emulation.
2134 depends on IA32_EMULATION
2136 config COMPAT_FOR_U64_ALIGNMENT
2140 config SYSVIPC_COMPAT
2142 depends on COMPAT && SYSVIPC
2146 depends on COMPAT && KEYS
2152 config HAVE_ATOMIC_IOMAP
2156 config HAVE_TEXT_POKE_SMP
2158 select STOP_MACHINE if SMP
2160 source "net/Kconfig"
2162 source "drivers/Kconfig"
2164 source "drivers/firmware/Kconfig"
2168 source "arch/x86/Kconfig.debug"
2170 source "security/Kconfig"
2172 source "crypto/Kconfig"
2174 source "arch/x86/kvm/Kconfig"
2176 source "lib/Kconfig"
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