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
19 select HAVE_AOUT if X86_32
20 select HAVE_UNSTABLE_SCHED_CLOCK
23 select HAVE_PCSPKR_PLATFORM
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_IRQ_PROBE
69 select GENERIC_PENDING_IRQ if SMP
70 select GENERIC_IRQ_SHOW
71 select IRQ_FORCED_THREADING
72 select USE_GENERIC_SMP_HELPERS if SMP
73 select HAVE_BPF_JIT if (X86_64 && NET)
75 select ARCH_HAVE_NMI_SAFE_CMPXCHG
77 config INSTRUCTION_DECODER
78 def_bool (KPROBES || PERF_EVENTS)
82 default "elf32-i386" if X86_32
83 default "elf64-x86-64" if X86_64
87 default "arch/x86/configs/i386_defconfig" if X86_32
88 default "arch/x86/configs/x86_64_defconfig" if X86_64
90 config GENERIC_CMOS_UPDATE
93 config CLOCKSOURCE_WATCHDOG
96 config GENERIC_CLOCKEVENTS
99 config ARCH_CLOCKSOURCE_DATA
103 config GENERIC_CLOCKEVENTS_BROADCAST
105 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
107 config LOCKDEP_SUPPORT
110 config STACKTRACE_SUPPORT
113 config HAVE_LATENCYTOP_SUPPORT
120 bool "DMA memory allocation support" if EXPERT
123 DMA memory allocation support allows devices with less than 32-bit
124 addressing to allocate within the first 16MB of address space.
125 Disable if no such devices will be used.
132 config NEED_DMA_MAP_STATE
133 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
135 config NEED_SG_DMA_LENGTH
138 config GENERIC_ISA_DMA
147 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
149 config GENERIC_BUG_RELATIVE_POINTERS
152 config GENERIC_HWEIGHT
158 config ARCH_MAY_HAVE_PC_FDC
161 config RWSEM_GENERIC_SPINLOCK
164 config RWSEM_XCHGADD_ALGORITHM
167 config ARCH_HAS_CPU_IDLE_WAIT
170 config GENERIC_CALIBRATE_DELAY
173 config GENERIC_TIME_VSYSCALL
177 config ARCH_HAS_CPU_RELAX
180 config ARCH_HAS_DEFAULT_IDLE
183 config ARCH_HAS_CACHE_LINE_SIZE
186 config HAVE_SETUP_PER_CPU_AREA
189 config NEED_PER_CPU_EMBED_FIRST_CHUNK
192 config NEED_PER_CPU_PAGE_FIRST_CHUNK
195 config ARCH_HIBERNATION_POSSIBLE
198 config ARCH_SUSPEND_POSSIBLE
205 config ARCH_POPULATES_NODE_MAP
212 config ARCH_SUPPORTS_OPTIMIZED_INLINING
215 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
218 config HAVE_INTEL_TXT
220 depends on EXPERIMENTAL && DMAR && ACPI
224 depends on X86_32 && SMP
228 depends on X86_64 && SMP
234 config X86_32_LAZY_GS
236 depends on X86_32 && !CC_STACKPROTECTOR
238 config ARCH_HWEIGHT_CFLAGS
240 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
241 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
246 config ARCH_CPU_PROBE_RELEASE
248 depends on HOTPLUG_CPU
250 source "init/Kconfig"
251 source "kernel/Kconfig.freezer"
253 menu "Processor type and features"
255 source "kernel/time/Kconfig"
258 bool "Symmetric multi-processing support"
260 This enables support for systems with more than one CPU. If you have
261 a system with only one CPU, like most personal computers, say N. If
262 you have a system with more than one CPU, say Y.
264 If you say N here, the kernel will run on single and multiprocessor
265 machines, but will use only one CPU of a multiprocessor machine. If
266 you say Y here, the kernel will run on many, but not all,
267 singleprocessor machines. On a singleprocessor machine, the kernel
268 will run faster if you say N here.
270 Note that if you say Y here and choose architecture "586" or
271 "Pentium" under "Processor family", the kernel will not work on 486
272 architectures. Similarly, multiprocessor kernels for the "PPro"
273 architecture may not work on all Pentium based boards.
275 People using multiprocessor machines who say Y here should also say
276 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
277 Management" code will be disabled if you say Y here.
279 See also <file:Documentation/i386/IO-APIC.txt>,
280 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
281 <http://www.tldp.org/docs.html#howto>.
283 If you don't know what to do here, say N.
286 bool "Support x2apic"
287 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
289 This enables x2apic support on CPUs that have this feature.
291 This allows 32-bit apic IDs (so it can support very large systems),
292 and accesses the local apic via MSRs not via mmio.
294 If you don't know what to do here, say N.
297 bool "Enable MPS table" if ACPI
299 depends on X86_LOCAL_APIC
301 For old smp systems that do not have proper acpi support. Newer systems
302 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
305 bool "Support for big SMP systems with more than 8 CPUs"
306 depends on X86_32 && SMP
308 This option is needed for the systems that have more than 8 CPUs
311 config X86_EXTENDED_PLATFORM
312 bool "Support for extended (non-PC) x86 platforms"
315 If you disable this option then the kernel will only support
316 standard PC platforms. (which covers the vast majority of
319 If you enable this option then you'll be able to select support
320 for the following (non-PC) 32 bit x86 platforms:
324 SGI 320/540 (Visual Workstation)
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:
347 If you have one of these systems, or if you want to build a
348 generic distribution kernel, say Y here - otherwise say N.
350 # This is an alphabetically sorted list of 64 bit extended platforms
351 # Please maintain the alphabetic order if and when there are additions
355 select PARAVIRT_GUEST
357 depends on X86_64 && PCI
358 depends on X86_EXTENDED_PLATFORM
360 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
361 supposed to run on these EM64T-based machines. Only choose this option
362 if you have one of these machines.
365 bool "SGI Ultraviolet"
367 depends on X86_EXTENDED_PLATFORM
369 depends on X86_X2APIC
371 This option is needed in order to support SGI Ultraviolet systems.
372 If you don't have one of these, you should say N here.
374 # Following is an alphabetically sorted list of 32 bit extended platforms
375 # Please maintain the alphabetic order if and when there are additions
378 bool "CE4100 TV platform"
380 depends on PCI_GODIRECT
382 depends on X86_EXTENDED_PLATFORM
383 select X86_REBOOTFIXUPS
385 select OF_EARLY_FLATTREE
387 Select for the Intel CE media processor (CE4100) SOC.
388 This option compiles in support for the CE4100 SOC for settop
389 boxes and media devices.
392 bool "Intel MID platform support"
394 depends on X86_EXTENDED_PLATFORM
396 Select to build a kernel capable of supporting Intel MID platform
397 systems which do not have the PCI legacy interfaces (Moorestown,
398 Medfield). If you are building for a PC class system say N here.
403 bool "Moorestown MID platform"
406 depends on X86_IO_APIC
411 select X86_PLATFORM_DEVICES
413 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
414 Internet Device(MID) platform. Moorestown consists of two chips:
415 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
416 Unlike standard x86 PCs, Moorestown does not have many legacy devices
417 nor standard legacy replacement devices/features. e.g. Moorestown does
418 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
423 bool "RDC R-321x SoC"
425 depends on X86_EXTENDED_PLATFORM
427 select X86_REBOOTFIXUPS
429 This option is needed for RDC R-321x system-on-chip, also known
431 If you don't have one of these chips, you should say N here.
433 config X86_32_NON_STANDARD
434 bool "Support non-standard 32-bit SMP architectures"
435 depends on X86_32 && SMP
436 depends on X86_EXTENDED_PLATFORM
438 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
439 subarchitectures. It is intended for a generic binary kernel.
440 if you select them all, kernel will probe it one by one. and will
443 # Alphabetically sorted list of Non standard 32 bit platforms
446 bool "NUMAQ (IBM/Sequent)"
447 depends on X86_32_NON_STANDARD
452 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
453 NUMA multiquad box. This changes the way that processors are
454 bootstrapped, and uses Clustered Logical APIC addressing mode instead
455 of Flat Logical. You will need a new lynxer.elf file to flash your
456 firmware with - send email to <Martin.Bligh@us.ibm.com>.
458 config X86_SUPPORTS_MEMORY_FAILURE
460 # MCE code calls memory_failure():
462 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
463 depends on !X86_NUMAQ
464 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
465 depends on X86_64 || !SPARSEMEM
466 select ARCH_SUPPORTS_MEMORY_FAILURE
469 bool "SGI 320/540 (Visual Workstation)"
470 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
471 depends on X86_32_NON_STANDARD
473 The SGI Visual Workstation series is an IA32-based workstation
474 based on SGI systems chips with some legacy PC hardware attached.
476 Say Y here to create a kernel to run on the SGI 320 or 540.
478 A kernel compiled for the Visual Workstation will run on general
479 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
482 bool "Summit/EXA (IBM x440)"
483 depends on X86_32_NON_STANDARD
485 This option is needed for IBM systems that use the Summit/EXA chipset.
486 In particular, it is needed for the x440.
489 bool "Unisys ES7000 IA32 series"
490 depends on X86_32_NON_STANDARD && X86_BIGSMP
492 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
493 supposed to run on an IA32-based Unisys ES7000 system.
496 tristate "Eurobraille/Iris poweroff module"
499 The Iris machines from EuroBraille do not have APM or ACPI support
500 to shut themselves down properly. A special I/O sequence is
501 needed to do so, which is what this module does at
504 This is only for Iris machines from EuroBraille.
508 config SCHED_OMIT_FRAME_POINTER
510 prompt "Single-depth WCHAN output"
513 Calculate simpler /proc/<PID>/wchan values. If this option
514 is disabled then wchan values will recurse back to the
515 caller function. This provides more accurate wchan values,
516 at the expense of slightly more scheduling overhead.
518 If in doubt, say "Y".
520 menuconfig PARAVIRT_GUEST
521 bool "Paravirtualized guest support"
523 Say Y here to get to see options related to running Linux under
524 various hypervisors. This option alone does not add any kernel code.
526 If you say N, all options in this submenu will be skipped and disabled.
530 config PARAVIRT_TIME_ACCOUNTING
531 bool "Paravirtual steal time accounting"
535 Select this option to enable fine granularity task steal time
536 accounting. Time spent executing other tasks in parallel with
537 the current vCPU is discounted from the vCPU power. To account for
538 that, there can be a small performance impact.
540 If in doubt, say N here.
542 source "arch/x86/xen/Kconfig"
545 bool "KVM paravirtualized clock"
547 select PARAVIRT_CLOCK
549 Turning on this option will allow you to run a paravirtualized clock
550 when running over the KVM hypervisor. Instead of relying on a PIT
551 (or probably other) emulation by the underlying device model, the host
552 provides the guest with timing infrastructure such as time of day, and
556 bool "KVM Guest support"
559 This option enables various optimizations for running under the KVM
562 source "arch/x86/lguest/Kconfig"
565 bool "Enable paravirtualization code"
567 This changes the kernel so it can modify itself when it is run
568 under a hypervisor, potentially improving performance significantly
569 over full virtualization. However, when run without a hypervisor
570 the kernel is theoretically slower and slightly larger.
572 config PARAVIRT_SPINLOCKS
573 bool "Paravirtualization layer for spinlocks"
574 depends on PARAVIRT && SMP && EXPERIMENTAL
576 Paravirtualized spinlocks allow a pvops backend to replace the
577 spinlock implementation with something virtualization-friendly
578 (for example, block the virtual CPU rather than spinning).
580 Unfortunately the downside is an up to 5% performance hit on
581 native kernels, with various workloads.
583 If you are unsure how to answer this question, answer N.
585 config PARAVIRT_CLOCK
590 config PARAVIRT_DEBUG
591 bool "paravirt-ops debugging"
592 depends on PARAVIRT && DEBUG_KERNEL
594 Enable to debug paravirt_ops internals. Specifically, BUG if
595 a paravirt_op is missing when it is called.
603 This option adds a kernel parameter 'memtest', which allows memtest
605 memtest=0, mean disabled; -- default
606 memtest=1, mean do 1 test pattern;
608 memtest=4, mean do 4 test patterns.
609 If you are unsure how to answer this question, answer N.
611 config X86_SUMMIT_NUMA
613 depends on X86_32 && NUMA && X86_32_NON_STANDARD
615 config X86_CYCLONE_TIMER
617 depends on X86_32_NON_STANDARD
619 source "arch/x86/Kconfig.cpu"
623 prompt "HPET Timer Support" if X86_32
625 Use the IA-PC HPET (High Precision Event Timer) to manage
626 time in preference to the PIT and RTC, if a HPET is
628 HPET is the next generation timer replacing legacy 8254s.
629 The HPET provides a stable time base on SMP
630 systems, unlike the TSC, but it is more expensive to access,
631 as it is off-chip. You can find the HPET spec at
632 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
634 You can safely choose Y here. However, HPET will only be
635 activated if the platform and the BIOS support this feature.
636 Otherwise the 8254 will be used for timing services.
638 Choose N to continue using the legacy 8254 timer.
640 config HPET_EMULATE_RTC
642 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
646 prompt "Langwell APB Timer Support" if X86_MRST
649 APB timer is the replacement for 8254, HPET on X86 MID platforms.
650 The APBT provides a stable time base on SMP
651 systems, unlike the TSC, but it is more expensive to access,
652 as it is off-chip. APB timers are always running regardless of CPU
653 C states, they are used as per CPU clockevent device when possible.
655 # Mark as expert because too many people got it wrong.
656 # The code disables itself when not needed.
659 bool "Enable DMI scanning" if EXPERT
661 Enabled scanning of DMI to identify machine quirks. Say Y
662 here unless you have verified that your setup is not
663 affected by entries in the DMI blacklist. Required by PNP
667 bool "GART IOMMU support" if EXPERT
670 depends on X86_64 && PCI && AMD_NB
672 Support for full DMA access of devices with 32bit memory access only
673 on systems with more than 3GB. This is usually needed for USB,
674 sound, many IDE/SATA chipsets and some other devices.
675 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
676 based hardware IOMMU and a software bounce buffer based IOMMU used
677 on Intel systems and as fallback.
678 The code is only active when needed (enough memory and limited
679 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
683 bool "IBM Calgary IOMMU support"
685 depends on X86_64 && PCI && EXPERIMENTAL
687 Support for hardware IOMMUs in IBM's xSeries x366 and x460
688 systems. Needed to run systems with more than 3GB of memory
689 properly with 32-bit PCI devices that do not support DAC
690 (Double Address Cycle). Calgary also supports bus level
691 isolation, where all DMAs pass through the IOMMU. This
692 prevents them from going anywhere except their intended
693 destination. This catches hard-to-find kernel bugs and
694 mis-behaving drivers and devices that do not use the DMA-API
695 properly to set up their DMA buffers. The IOMMU can be
696 turned off at boot time with the iommu=off parameter.
697 Normally the kernel will make the right choice by itself.
700 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
702 prompt "Should Calgary be enabled by default?"
703 depends on CALGARY_IOMMU
705 Should Calgary be enabled by default? if you choose 'y', Calgary
706 will be used (if it exists). If you choose 'n', Calgary will not be
707 used even if it exists. If you choose 'n' and would like to use
708 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
711 # need this always selected by IOMMU for the VIA workaround
715 Support for software bounce buffers used on x86-64 systems
716 which don't have a hardware IOMMU (e.g. the current generation
717 of Intel's x86-64 CPUs). Using this PCI devices which can only
718 access 32-bits of memory can be used on systems with more than
719 3 GB of memory. If unsure, say Y.
722 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
725 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
726 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
727 select CPUMASK_OFFSTACK
729 Enable maximum number of CPUS and NUMA Nodes for this architecture.
733 int "Maximum number of CPUs" if SMP && !MAXSMP
734 range 2 8 if SMP && X86_32 && !X86_BIGSMP
735 range 2 512 if SMP && !MAXSMP
737 default "4096" if MAXSMP
738 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
741 This allows you to specify the maximum number of CPUs which this
742 kernel will support. The maximum supported value is 512 and the
743 minimum value which makes sense is 2.
745 This is purely to save memory - each supported CPU adds
746 approximately eight kilobytes to the kernel image.
749 bool "SMT (Hyperthreading) scheduler support"
752 SMT scheduler support improves the CPU scheduler's decision making
753 when dealing with Intel Pentium 4 chips with HyperThreading at a
754 cost of slightly increased overhead in some places. If unsure say
759 prompt "Multi-core scheduler support"
762 Multi-core scheduler support improves the CPU scheduler's decision
763 making when dealing with multi-core CPU chips at a cost of slightly
764 increased overhead in some places. If unsure say N here.
766 config IRQ_TIME_ACCOUNTING
767 bool "Fine granularity task level IRQ time accounting"
770 Select this option to enable fine granularity task irq time
771 accounting. This is done by reading a timestamp on each
772 transitions between softirq and hardirq state, so there can be a
773 small performance impact.
775 If in doubt, say N here.
777 source "kernel/Kconfig.preempt"
780 bool "Local APIC support on uniprocessors"
781 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
783 A local APIC (Advanced Programmable Interrupt Controller) is an
784 integrated interrupt controller in the CPU. If you have a single-CPU
785 system which has a processor with a local APIC, you can say Y here to
786 enable and use it. If you say Y here even though your machine doesn't
787 have a local APIC, then the kernel will still run with no slowdown at
788 all. The local APIC supports CPU-generated self-interrupts (timer,
789 performance counters), and the NMI watchdog which detects hard
793 bool "IO-APIC support on uniprocessors"
794 depends on X86_UP_APIC
796 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
797 SMP-capable replacement for PC-style interrupt controllers. Most
798 SMP systems and many recent uniprocessor systems have one.
800 If you have a single-CPU system with an IO-APIC, you can say Y here
801 to use it. If you say Y here even though your machine doesn't have
802 an IO-APIC, then the kernel will still run with no slowdown at all.
804 config X86_LOCAL_APIC
806 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
810 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
812 config X86_VISWS_APIC
814 depends on X86_32 && X86_VISWS
816 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
817 bool "Reroute for broken boot IRQs"
818 depends on X86_IO_APIC
820 This option enables a workaround that fixes a source of
821 spurious interrupts. This is recommended when threaded
822 interrupt handling is used on systems where the generation of
823 superfluous "boot interrupts" cannot be disabled.
825 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
826 entry in the chipset's IO-APIC is masked (as, e.g. the RT
827 kernel does during interrupt handling). On chipsets where this
828 boot IRQ generation cannot be disabled, this workaround keeps
829 the original IRQ line masked so that only the equivalent "boot
830 IRQ" is delivered to the CPUs. The workaround also tells the
831 kernel to set up the IRQ handler on the boot IRQ line. In this
832 way only one interrupt is delivered to the kernel. Otherwise
833 the spurious second interrupt may cause the kernel to bring
834 down (vital) interrupt lines.
836 Only affects "broken" chipsets. Interrupt sharing may be
837 increased on these systems.
840 bool "Machine Check / overheating reporting"
842 Machine Check support allows the processor to notify the
843 kernel if it detects a problem (e.g. overheating, data corruption).
844 The action the kernel takes depends on the severity of the problem,
845 ranging from warning messages to halting the machine.
849 prompt "Intel MCE features"
850 depends on X86_MCE && X86_LOCAL_APIC
852 Additional support for intel specific MCE features such as
857 prompt "AMD MCE features"
858 depends on X86_MCE && X86_LOCAL_APIC
860 Additional support for AMD specific MCE features such as
861 the DRAM Error Threshold.
863 config X86_ANCIENT_MCE
864 bool "Support for old Pentium 5 / WinChip machine checks"
865 depends on X86_32 && X86_MCE
867 Include support for machine check handling on old Pentium 5 or WinChip
868 systems. These typically need to be enabled explicitely on the command
871 config X86_MCE_THRESHOLD
872 depends on X86_MCE_AMD || X86_MCE_INTEL
875 config X86_MCE_INJECT
877 tristate "Machine check injector support"
879 Provide support for injecting machine checks for testing purposes.
880 If you don't know what a machine check is and you don't do kernel
881 QA it is safe to say n.
883 config X86_THERMAL_VECTOR
885 depends on X86_MCE_INTEL
888 bool "Enable VM86 support" if EXPERT
892 This option is required by programs like DOSEMU to run 16-bit legacy
893 code on X86 processors. It also may be needed by software like
894 XFree86 to initialize some video cards via BIOS. Disabling this
895 option saves about 6k.
898 tristate "Toshiba Laptop support"
901 This adds a driver to safely access the System Management Mode of
902 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
903 not work on models with a Phoenix BIOS. The System Management Mode
904 is used to set the BIOS and power saving options on Toshiba portables.
906 For information on utilities to make use of this driver see the
907 Toshiba Linux utilities web site at:
908 <http://www.buzzard.org.uk/toshiba/>.
910 Say Y if you intend to run this kernel on a Toshiba portable.
914 tristate "Dell laptop support"
917 This adds a driver to safely access the System Management Mode
918 of the CPU on the Dell Inspiron 8000. The System Management Mode
919 is used to read cpu temperature and cooling fan status and to
920 control the fans on the I8K portables.
922 This driver has been tested only on the Inspiron 8000 but it may
923 also work with other Dell laptops. You can force loading on other
924 models by passing the parameter `force=1' to the module. Use at
927 For information on utilities to make use of this driver see the
928 I8K Linux utilities web site at:
929 <http://people.debian.org/~dz/i8k/>
931 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
934 config X86_REBOOTFIXUPS
935 bool "Enable X86 board specific fixups for reboot"
938 This enables chipset and/or board specific fixups to be done
939 in order to get reboot to work correctly. This is only needed on
940 some combinations of hardware and BIOS. The symptom, for which
941 this config is intended, is when reboot ends with a stalled/hung
944 Currently, the only fixup is for the Geode machines using
945 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
947 Say Y if you want to enable the fixup. Currently, it's safe to
948 enable this option even if you don't need it.
952 tristate "/dev/cpu/microcode - microcode support"
955 If you say Y here, you will be able to update the microcode on
956 certain Intel and AMD processors. The Intel support is for the
957 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
958 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
959 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
960 You will obviously need the actual microcode binary data itself
961 which is not shipped with the Linux kernel.
963 This option selects the general module only, you need to select
964 at least one vendor specific module as well.
966 To compile this driver as a module, choose M here: the
967 module will be called microcode.
969 config MICROCODE_INTEL
970 bool "Intel microcode patch loading support"
975 This options enables microcode patch loading support for Intel
978 For latest news and information on obtaining all the required
979 Intel ingredients for this driver, check:
980 <http://www.urbanmyth.org/microcode/>.
983 bool "AMD microcode patch loading support"
987 If you select this option, microcode patch loading support for AMD
988 processors will be enabled.
990 config MICROCODE_OLD_INTERFACE
995 tristate "/dev/cpu/*/msr - Model-specific register support"
997 This device gives privileged processes access to the x86
998 Model-Specific Registers (MSRs). It is a character device with
999 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1000 MSR accesses are directed to a specific CPU on multi-processor
1004 tristate "/dev/cpu/*/cpuid - CPU information support"
1006 This device gives processes access to the x86 CPUID instruction to
1007 be executed on a specific processor. It is a character device
1008 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1012 prompt "High Memory Support"
1013 default HIGHMEM64G if X86_NUMAQ
1019 depends on !X86_NUMAQ
1021 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1022 However, the address space of 32-bit x86 processors is only 4
1023 Gigabytes large. That means that, if you have a large amount of
1024 physical memory, not all of it can be "permanently mapped" by the
1025 kernel. The physical memory that's not permanently mapped is called
1028 If you are compiling a kernel which will never run on a machine with
1029 more than 1 Gigabyte total physical RAM, answer "off" here (default
1030 choice and suitable for most users). This will result in a "3GB/1GB"
1031 split: 3GB are mapped so that each process sees a 3GB virtual memory
1032 space and the remaining part of the 4GB virtual memory space is used
1033 by the kernel to permanently map as much physical memory as
1036 If the machine has between 1 and 4 Gigabytes physical RAM, then
1039 If more than 4 Gigabytes is used then answer "64GB" here. This
1040 selection turns Intel PAE (Physical Address Extension) mode on.
1041 PAE implements 3-level paging on IA32 processors. PAE is fully
1042 supported by Linux, PAE mode is implemented on all recent Intel
1043 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1044 then the kernel will not boot on CPUs that don't support PAE!
1046 The actual amount of total physical memory will either be
1047 auto detected or can be forced by using a kernel command line option
1048 such as "mem=256M". (Try "man bootparam" or see the documentation of
1049 your boot loader (lilo or loadlin) about how to pass options to the
1050 kernel at boot time.)
1052 If unsure, say "off".
1056 depends on !X86_NUMAQ
1058 Select this if you have a 32-bit processor and between 1 and 4
1059 gigabytes of physical RAM.
1063 depends on !M386 && !M486
1066 Select this if you have a 32-bit processor and more than 4
1067 gigabytes of physical RAM.
1072 depends on EXPERIMENTAL
1073 prompt "Memory split" if EXPERT
1077 Select the desired split between kernel and user memory.
1079 If the address range available to the kernel is less than the
1080 physical memory installed, the remaining memory will be available
1081 as "high memory". Accessing high memory is a little more costly
1082 than low memory, as it needs to be mapped into the kernel first.
1083 Note that increasing the kernel address space limits the range
1084 available to user programs, making the address space there
1085 tighter. Selecting anything other than the default 3G/1G split
1086 will also likely make your kernel incompatible with binary-only
1089 If you are not absolutely sure what you are doing, leave this
1093 bool "3G/1G user/kernel split"
1094 config VMSPLIT_3G_OPT
1096 bool "3G/1G user/kernel split (for full 1G low memory)"
1098 bool "2G/2G user/kernel split"
1099 config VMSPLIT_2G_OPT
1101 bool "2G/2G user/kernel split (for full 2G low memory)"
1103 bool "1G/3G user/kernel split"
1108 default 0xB0000000 if VMSPLIT_3G_OPT
1109 default 0x80000000 if VMSPLIT_2G
1110 default 0x78000000 if VMSPLIT_2G_OPT
1111 default 0x40000000 if VMSPLIT_1G
1117 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1120 bool "PAE (Physical Address Extension) Support"
1121 depends on X86_32 && !HIGHMEM4G
1123 PAE is required for NX support, and furthermore enables
1124 larger swapspace support for non-overcommit purposes. It
1125 has the cost of more pagetable lookup overhead, and also
1126 consumes more pagetable space per process.
1128 config ARCH_PHYS_ADDR_T_64BIT
1129 def_bool X86_64 || X86_PAE
1131 config ARCH_DMA_ADDR_T_64BIT
1132 def_bool X86_64 || HIGHMEM64G
1134 config DIRECT_GBPAGES
1135 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1139 Allow the kernel linear mapping to use 1GB pages on CPUs that
1140 support it. This can improve the kernel's performance a tiny bit by
1141 reducing TLB pressure. If in doubt, say "Y".
1143 # Common NUMA Features
1145 bool "Numa Memory Allocation and Scheduler Support"
1147 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1148 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1150 Enable NUMA (Non Uniform Memory Access) support.
1152 The kernel will try to allocate memory used by a CPU on the
1153 local memory controller of the CPU and add some more
1154 NUMA awareness to the kernel.
1156 For 64-bit this is recommended if the system is Intel Core i7
1157 (or later), AMD Opteron, or EM64T NUMA.
1159 For 32-bit this is only needed on (rare) 32-bit-only platforms
1160 that support NUMA topologies, such as NUMAQ / Summit, or if you
1161 boot a 32-bit kernel on a 64-bit NUMA platform.
1163 Otherwise, you should say N.
1165 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1166 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1170 prompt "Old style AMD Opteron NUMA detection"
1171 depends on X86_64 && NUMA && PCI
1173 Enable AMD NUMA node topology detection. You should say Y here if
1174 you have a multi processor AMD system. This uses an old method to
1175 read the NUMA configuration directly from the builtin Northbridge
1176 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1177 which also takes priority if both are compiled in.
1179 config X86_64_ACPI_NUMA
1181 prompt "ACPI NUMA detection"
1182 depends on X86_64 && NUMA && ACPI && PCI
1185 Enable ACPI SRAT based node topology detection.
1187 # Some NUMA nodes have memory ranges that span
1188 # other nodes. Even though a pfn is valid and
1189 # between a node's start and end pfns, it may not
1190 # reside on that node. See memmap_init_zone()
1192 config NODES_SPAN_OTHER_NODES
1194 depends on X86_64_ACPI_NUMA
1197 bool "NUMA emulation"
1200 Enable NUMA emulation. A flat machine will be split
1201 into virtual nodes when booted with "numa=fake=N", where N is the
1202 number of nodes. This is only useful for debugging.
1205 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1207 default "10" if MAXSMP
1208 default "6" if X86_64
1209 default "4" if X86_NUMAQ
1211 depends on NEED_MULTIPLE_NODES
1213 Specify the maximum number of NUMA Nodes available on the target
1214 system. Increases memory reserved to accommodate various tables.
1216 config HAVE_ARCH_BOOTMEM
1218 depends on X86_32 && NUMA
1220 config HAVE_ARCH_ALLOC_REMAP
1222 depends on X86_32 && NUMA
1224 config ARCH_HAVE_MEMORY_PRESENT
1226 depends on X86_32 && DISCONTIGMEM
1228 config NEED_NODE_MEMMAP_SIZE
1230 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1232 config ARCH_FLATMEM_ENABLE
1234 depends on X86_32 && !NUMA
1236 config ARCH_DISCONTIGMEM_ENABLE
1238 depends on NUMA && X86_32
1240 config ARCH_DISCONTIGMEM_DEFAULT
1242 depends on NUMA && X86_32
1244 config ARCH_SPARSEMEM_ENABLE
1246 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1247 select SPARSEMEM_STATIC if X86_32
1248 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1250 config ARCH_SPARSEMEM_DEFAULT
1254 config ARCH_SELECT_MEMORY_MODEL
1256 depends on ARCH_SPARSEMEM_ENABLE
1258 config ARCH_MEMORY_PROBE
1260 depends on MEMORY_HOTPLUG
1262 config ARCH_PROC_KCORE_TEXT
1264 depends on X86_64 && PROC_KCORE
1266 config ILLEGAL_POINTER_VALUE
1269 default 0xdead000000000000 if X86_64
1274 bool "Allocate 3rd-level pagetables from highmem"
1277 The VM uses one page table entry for each page of physical memory.
1278 For systems with a lot of RAM, this can be wasteful of precious
1279 low memory. Setting this option will put user-space page table
1280 entries in high memory.
1282 config X86_CHECK_BIOS_CORRUPTION
1283 bool "Check for low memory corruption"
1285 Periodically check for memory corruption in low memory, which
1286 is suspected to be caused by BIOS. Even when enabled in the
1287 configuration, it is disabled at runtime. Enable it by
1288 setting "memory_corruption_check=1" on the kernel command
1289 line. By default it scans the low 64k of memory every 60
1290 seconds; see the memory_corruption_check_size and
1291 memory_corruption_check_period parameters in
1292 Documentation/kernel-parameters.txt to adjust this.
1294 When enabled with the default parameters, this option has
1295 almost no overhead, as it reserves a relatively small amount
1296 of memory and scans it infrequently. It both detects corruption
1297 and prevents it from affecting the running system.
1299 It is, however, intended as a diagnostic tool; if repeatable
1300 BIOS-originated corruption always affects the same memory,
1301 you can use memmap= to prevent the kernel from using that
1304 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1305 bool "Set the default setting of memory_corruption_check"
1306 depends on X86_CHECK_BIOS_CORRUPTION
1309 Set whether the default state of memory_corruption_check is
1312 config X86_RESERVE_LOW
1313 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1317 Specify the amount of low memory to reserve for the BIOS.
1319 The first page contains BIOS data structures that the kernel
1320 must not use, so that page must always be reserved.
1322 By default we reserve the first 64K of physical RAM, as a
1323 number of BIOSes are known to corrupt that memory range
1324 during events such as suspend/resume or monitor cable
1325 insertion, so it must not be used by the kernel.
1327 You can set this to 4 if you are absolutely sure that you
1328 trust the BIOS to get all its memory reservations and usages
1329 right. If you know your BIOS have problems beyond the
1330 default 64K area, you can set this to 640 to avoid using the
1331 entire low memory range.
1333 If you have doubts about the BIOS (e.g. suspend/resume does
1334 not work or there's kernel crashes after certain hardware
1335 hotplug events) then you might want to enable
1336 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1337 typical corruption patterns.
1339 Leave this to the default value of 64 if you are unsure.
1341 config MATH_EMULATION
1343 prompt "Math emulation" if X86_32
1345 Linux can emulate a math coprocessor (used for floating point
1346 operations) if you don't have one. 486DX and Pentium processors have
1347 a math coprocessor built in, 486SX and 386 do not, unless you added
1348 a 487DX or 387, respectively. (The messages during boot time can
1349 give you some hints here ["man dmesg"].) Everyone needs either a
1350 coprocessor or this emulation.
1352 If you don't have a math coprocessor, you need to say Y here; if you
1353 say Y here even though you have a coprocessor, the coprocessor will
1354 be used nevertheless. (This behavior can be changed with the kernel
1355 command line option "no387", which comes handy if your coprocessor
1356 is broken. Try "man bootparam" or see the documentation of your boot
1357 loader (lilo or loadlin) about how to pass options to the kernel at
1358 boot time.) This means that it is a good idea to say Y here if you
1359 intend to use this kernel on different machines.
1361 More information about the internals of the Linux math coprocessor
1362 emulation can be found in <file:arch/x86/math-emu/README>.
1364 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1365 kernel, it won't hurt.
1369 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1371 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1372 the Memory Type Range Registers (MTRRs) may be used to control
1373 processor access to memory ranges. This is most useful if you have
1374 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1375 allows bus write transfers to be combined into a larger transfer
1376 before bursting over the PCI/AGP bus. This can increase performance
1377 of image write operations 2.5 times or more. Saying Y here creates a
1378 /proc/mtrr file which may be used to manipulate your processor's
1379 MTRRs. Typically the X server should use this.
1381 This code has a reasonably generic interface so that similar
1382 control registers on other processors can be easily supported
1385 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1386 Registers (ARRs) which provide a similar functionality to MTRRs. For
1387 these, the ARRs are used to emulate the MTRRs.
1388 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1389 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1390 write-combining. All of these processors are supported by this code
1391 and it makes sense to say Y here if you have one of them.
1393 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1394 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1395 can lead to all sorts of problems, so it's good to say Y here.
1397 You can safely say Y even if your machine doesn't have MTRRs, you'll
1398 just add about 9 KB to your kernel.
1400 See <file:Documentation/x86/mtrr.txt> for more information.
1402 config MTRR_SANITIZER
1404 prompt "MTRR cleanup support"
1407 Convert MTRR layout from continuous to discrete, so X drivers can
1408 add writeback entries.
1410 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1411 The largest mtrr entry size for a continuous block can be set with
1416 config MTRR_SANITIZER_ENABLE_DEFAULT
1417 int "MTRR cleanup enable value (0-1)"
1420 depends on MTRR_SANITIZER
1422 Enable mtrr cleanup default value
1424 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1425 int "MTRR cleanup spare reg num (0-7)"
1428 depends on MTRR_SANITIZER
1430 mtrr cleanup spare entries default, it can be changed via
1431 mtrr_spare_reg_nr=N on the kernel command line.
1435 prompt "x86 PAT support" if EXPERT
1438 Use PAT attributes to setup page level cache control.
1440 PATs are the modern equivalents of MTRRs and are much more
1441 flexible than MTRRs.
1443 Say N here if you see bootup problems (boot crash, boot hang,
1444 spontaneous reboots) or a non-working video driver.
1448 config ARCH_USES_PG_UNCACHED
1453 bool "EFI runtime service support"
1456 This enables the kernel to use EFI runtime services that are
1457 available (such as the EFI variable services).
1459 This option is only useful on systems that have EFI firmware.
1460 In addition, you should use the latest ELILO loader available
1461 at <http://elilo.sourceforge.net> in order to take advantage
1462 of EFI runtime services. However, even with this option, the
1463 resultant kernel should continue to boot on existing non-EFI
1468 prompt "Enable seccomp to safely compute untrusted bytecode"
1470 This kernel feature is useful for number crunching applications
1471 that may need to compute untrusted bytecode during their
1472 execution. By using pipes or other transports made available to
1473 the process as file descriptors supporting the read/write
1474 syscalls, it's possible to isolate those applications in
1475 their own address space using seccomp. Once seccomp is
1476 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1477 and the task is only allowed to execute a few safe syscalls
1478 defined by each seccomp mode.
1480 If unsure, say Y. Only embedded should say N here.
1482 config CC_STACKPROTECTOR
1483 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1485 This option turns on the -fstack-protector GCC feature. This
1486 feature puts, at the beginning of functions, a canary value on
1487 the stack just before the return address, and validates
1488 the value just before actually returning. Stack based buffer
1489 overflows (that need to overwrite this return address) now also
1490 overwrite the canary, which gets detected and the attack is then
1491 neutralized via a kernel panic.
1493 This feature requires gcc version 4.2 or above, or a distribution
1494 gcc with the feature backported. Older versions are automatically
1495 detected and for those versions, this configuration option is
1496 ignored. (and a warning is printed during bootup)
1498 source kernel/Kconfig.hz
1501 bool "kexec system call"
1503 kexec is a system call that implements the ability to shutdown your
1504 current kernel, and to start another kernel. It is like a reboot
1505 but it is independent of the system firmware. And like a reboot
1506 you can start any kernel with it, not just Linux.
1508 The name comes from the similarity to the exec system call.
1510 It is an ongoing process to be certain the hardware in a machine
1511 is properly shutdown, so do not be surprised if this code does not
1512 initially work for you. It may help to enable device hotplugging
1513 support. As of this writing the exact hardware interface is
1514 strongly in flux, so no good recommendation can be made.
1517 bool "kernel crash dumps"
1518 depends on X86_64 || (X86_32 && HIGHMEM)
1520 Generate crash dump after being started by kexec.
1521 This should be normally only set in special crash dump kernels
1522 which are loaded in the main kernel with kexec-tools into
1523 a specially reserved region and then later executed after
1524 a crash by kdump/kexec. The crash dump kernel must be compiled
1525 to a memory address not used by the main kernel or BIOS using
1526 PHYSICAL_START, or it must be built as a relocatable image
1527 (CONFIG_RELOCATABLE=y).
1528 For more details see Documentation/kdump/kdump.txt
1531 bool "kexec jump (EXPERIMENTAL)"
1532 depends on EXPERIMENTAL
1533 depends on KEXEC && HIBERNATION
1535 Jump between original kernel and kexeced kernel and invoke
1536 code in physical address mode via KEXEC
1538 config PHYSICAL_START
1539 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1542 This gives the physical address where the kernel is loaded.
1544 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1545 bzImage will decompress itself to above physical address and
1546 run from there. Otherwise, bzImage will run from the address where
1547 it has been loaded by the boot loader and will ignore above physical
1550 In normal kdump cases one does not have to set/change this option
1551 as now bzImage can be compiled as a completely relocatable image
1552 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1553 address. This option is mainly useful for the folks who don't want
1554 to use a bzImage for capturing the crash dump and want to use a
1555 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1556 to be specifically compiled to run from a specific memory area
1557 (normally a reserved region) and this option comes handy.
1559 So if you are using bzImage for capturing the crash dump,
1560 leave the value here unchanged to 0x1000000 and set
1561 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1562 for capturing the crash dump change this value to start of
1563 the reserved region. In other words, it can be set based on
1564 the "X" value as specified in the "crashkernel=YM@XM"
1565 command line boot parameter passed to the panic-ed
1566 kernel. Please take a look at Documentation/kdump/kdump.txt
1567 for more details about crash dumps.
1569 Usage of bzImage for capturing the crash dump is recommended as
1570 one does not have to build two kernels. Same kernel can be used
1571 as production kernel and capture kernel. Above option should have
1572 gone away after relocatable bzImage support is introduced. But it
1573 is present because there are users out there who continue to use
1574 vmlinux for dump capture. This option should go away down the
1577 Don't change this unless you know what you are doing.
1580 bool "Build a relocatable kernel"
1583 This builds a kernel image that retains relocation information
1584 so it can be loaded someplace besides the default 1MB.
1585 The relocations tend to make the kernel binary about 10% larger,
1586 but are discarded at runtime.
1588 One use is for the kexec on panic case where the recovery kernel
1589 must live at a different physical address than the primary
1592 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1593 it has been loaded at and the compile time physical address
1594 (CONFIG_PHYSICAL_START) is ignored.
1596 # Relocation on x86-32 needs some additional build support
1597 config X86_NEED_RELOCS
1599 depends on X86_32 && RELOCATABLE
1601 config PHYSICAL_ALIGN
1602 hex "Alignment value to which kernel should be aligned" if X86_32
1604 range 0x2000 0x1000000
1606 This value puts the alignment restrictions on physical address
1607 where kernel is loaded and run from. Kernel is compiled for an
1608 address which meets above alignment restriction.
1610 If bootloader loads the kernel at a non-aligned address and
1611 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1612 address aligned to above value and run from there.
1614 If bootloader loads the kernel at a non-aligned address and
1615 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1616 load address and decompress itself to the address it has been
1617 compiled for and run from there. The address for which kernel is
1618 compiled already meets above alignment restrictions. Hence the
1619 end result is that kernel runs from a physical address meeting
1620 above alignment restrictions.
1622 Don't change this unless you know what you are doing.
1625 bool "Support for hot-pluggable CPUs"
1626 depends on SMP && HOTPLUG
1628 Say Y here to allow turning CPUs off and on. CPUs can be
1629 controlled through /sys/devices/system/cpu.
1630 ( Note: power management support will enable this option
1631 automatically on SMP systems. )
1632 Say N if you want to disable CPU hotplug.
1636 prompt "Compat VDSO support"
1637 depends on X86_32 || IA32_EMULATION
1639 Map the 32-bit VDSO to the predictable old-style address too.
1641 Say N here if you are running a sufficiently recent glibc
1642 version (2.3.3 or later), to remove the high-mapped
1643 VDSO mapping and to exclusively use the randomized VDSO.
1648 bool "Built-in kernel command line"
1650 Allow for specifying boot arguments to the kernel at
1651 build time. On some systems (e.g. embedded ones), it is
1652 necessary or convenient to provide some or all of the
1653 kernel boot arguments with the kernel itself (that is,
1654 to not rely on the boot loader to provide them.)
1656 To compile command line arguments into the kernel,
1657 set this option to 'Y', then fill in the
1658 the boot arguments in CONFIG_CMDLINE.
1660 Systems with fully functional boot loaders (i.e. non-embedded)
1661 should leave this option set to 'N'.
1664 string "Built-in kernel command string"
1665 depends on CMDLINE_BOOL
1668 Enter arguments here that should be compiled into the kernel
1669 image and used at boot time. If the boot loader provides a
1670 command line at boot time, it is appended to this string to
1671 form the full kernel command line, when the system boots.
1673 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1674 change this behavior.
1676 In most cases, the command line (whether built-in or provided
1677 by the boot loader) should specify the device for the root
1680 config CMDLINE_OVERRIDE
1681 bool "Built-in command line overrides boot loader arguments"
1682 depends on CMDLINE_BOOL
1684 Set this option to 'Y' to have the kernel ignore the boot loader
1685 command line, and use ONLY the built-in command line.
1687 This is used to work around broken boot loaders. This should
1688 be set to 'N' under normal conditions.
1692 config ARCH_ENABLE_MEMORY_HOTPLUG
1694 depends on X86_64 || (X86_32 && HIGHMEM)
1696 config ARCH_ENABLE_MEMORY_HOTREMOVE
1698 depends on MEMORY_HOTPLUG
1700 config USE_PERCPU_NUMA_NODE_ID
1704 menu "Power management and ACPI options"
1706 config ARCH_HIBERNATION_HEADER
1708 depends on X86_64 && HIBERNATION
1710 source "kernel/power/Kconfig"
1712 source "drivers/acpi/Kconfig"
1714 source "drivers/sfi/Kconfig"
1718 depends on APM || APM_MODULE
1721 tristate "APM (Advanced Power Management) BIOS support"
1722 depends on X86_32 && PM_SLEEP
1724 APM is a BIOS specification for saving power using several different
1725 techniques. This is mostly useful for battery powered laptops with
1726 APM compliant BIOSes. If you say Y here, the system time will be
1727 reset after a RESUME operation, the /proc/apm device will provide
1728 battery status information, and user-space programs will receive
1729 notification of APM "events" (e.g. battery status change).
1731 If you select "Y" here, you can disable actual use of the APM
1732 BIOS by passing the "apm=off" option to the kernel at boot time.
1734 Note that the APM support is almost completely disabled for
1735 machines with more than one CPU.
1737 In order to use APM, you will need supporting software. For location
1738 and more information, read <file:Documentation/power/apm-acpi.txt>
1739 and the Battery Powered Linux mini-HOWTO, available from
1740 <http://www.tldp.org/docs.html#howto>.
1742 This driver does not spin down disk drives (see the hdparm(8)
1743 manpage ("man 8 hdparm") for that), and it doesn't turn off
1744 VESA-compliant "green" monitors.
1746 This driver does not support the TI 4000M TravelMate and the ACER
1747 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1748 desktop machines also don't have compliant BIOSes, and this driver
1749 may cause those machines to panic during the boot phase.
1751 Generally, if you don't have a battery in your machine, there isn't
1752 much point in using this driver and you should say N. If you get
1753 random kernel OOPSes or reboots that don't seem to be related to
1754 anything, try disabling/enabling this option (or disabling/enabling
1757 Some other things you should try when experiencing seemingly random,
1760 1) make sure that you have enough swap space and that it is
1762 2) pass the "no-hlt" option to the kernel
1763 3) switch on floating point emulation in the kernel and pass
1764 the "no387" option to the kernel
1765 4) pass the "floppy=nodma" option to the kernel
1766 5) pass the "mem=4M" option to the kernel (thereby disabling
1767 all but the first 4 MB of RAM)
1768 6) make sure that the CPU is not over clocked.
1769 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1770 8) disable the cache from your BIOS settings
1771 9) install a fan for the video card or exchange video RAM
1772 10) install a better fan for the CPU
1773 11) exchange RAM chips
1774 12) exchange the motherboard.
1776 To compile this driver as a module, choose M here: the
1777 module will be called apm.
1781 config APM_IGNORE_USER_SUSPEND
1782 bool "Ignore USER SUSPEND"
1784 This option will ignore USER SUSPEND requests. On machines with a
1785 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1786 series notebooks, it is necessary to say Y because of a BIOS bug.
1788 config APM_DO_ENABLE
1789 bool "Enable PM at boot time"
1791 Enable APM features at boot time. From page 36 of the APM BIOS
1792 specification: "When disabled, the APM BIOS does not automatically
1793 power manage devices, enter the Standby State, enter the Suspend
1794 State, or take power saving steps in response to CPU Idle calls."
1795 This driver will make CPU Idle calls when Linux is idle (unless this
1796 feature is turned off -- see "Do CPU IDLE calls", below). This
1797 should always save battery power, but more complicated APM features
1798 will be dependent on your BIOS implementation. You may need to turn
1799 this option off if your computer hangs at boot time when using APM
1800 support, or if it beeps continuously instead of suspending. Turn
1801 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1802 T400CDT. This is off by default since most machines do fine without
1806 bool "Make CPU Idle calls when idle"
1808 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1809 On some machines, this can activate improved power savings, such as
1810 a slowed CPU clock rate, when the machine is idle. These idle calls
1811 are made after the idle loop has run for some length of time (e.g.,
1812 333 mS). On some machines, this will cause a hang at boot time or
1813 whenever the CPU becomes idle. (On machines with more than one CPU,
1814 this option does nothing.)
1816 config APM_DISPLAY_BLANK
1817 bool "Enable console blanking using APM"
1819 Enable console blanking using the APM. Some laptops can use this to
1820 turn off the LCD backlight when the screen blanker of the Linux
1821 virtual console blanks the screen. Note that this is only used by
1822 the virtual console screen blanker, and won't turn off the backlight
1823 when using the X Window system. This also doesn't have anything to
1824 do with your VESA-compliant power-saving monitor. Further, this
1825 option doesn't work for all laptops -- it might not turn off your
1826 backlight at all, or it might print a lot of errors to the console,
1827 especially if you are using gpm.
1829 config APM_ALLOW_INTS
1830 bool "Allow interrupts during APM BIOS calls"
1832 Normally we disable external interrupts while we are making calls to
1833 the APM BIOS as a measure to lessen the effects of a badly behaving
1834 BIOS implementation. The BIOS should reenable interrupts if it
1835 needs to. Unfortunately, some BIOSes do not -- especially those in
1836 many of the newer IBM Thinkpads. If you experience hangs when you
1837 suspend, try setting this to Y. Otherwise, say N.
1841 source "drivers/cpufreq/Kconfig"
1843 source "drivers/cpuidle/Kconfig"
1845 source "drivers/idle/Kconfig"
1850 menu "Bus options (PCI etc.)"
1855 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1857 Find out whether you have a PCI motherboard. PCI is the name of a
1858 bus system, i.e. the way the CPU talks to the other stuff inside
1859 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1860 VESA. If you have PCI, say Y, otherwise N.
1863 prompt "PCI access mode"
1864 depends on X86_32 && PCI
1867 On PCI systems, the BIOS can be used to detect the PCI devices and
1868 determine their configuration. However, some old PCI motherboards
1869 have BIOS bugs and may crash if this is done. Also, some embedded
1870 PCI-based systems don't have any BIOS at all. Linux can also try to
1871 detect the PCI hardware directly without using the BIOS.
1873 With this option, you can specify how Linux should detect the
1874 PCI devices. If you choose "BIOS", the BIOS will be used,
1875 if you choose "Direct", the BIOS won't be used, and if you
1876 choose "MMConfig", then PCI Express MMCONFIG will be used.
1877 If you choose "Any", the kernel will try MMCONFIG, then the
1878 direct access method and falls back to the BIOS if that doesn't
1879 work. If unsure, go with the default, which is "Any".
1884 config PCI_GOMMCONFIG
1901 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1903 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1906 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
1910 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1914 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1918 depends on PCI && XEN
1926 bool "Support mmconfig PCI config space access"
1927 depends on X86_64 && PCI && ACPI
1929 config PCI_CNB20LE_QUIRK
1930 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1932 depends on PCI && EXPERIMENTAL
1934 Read the PCI windows out of the CNB20LE host bridge. This allows
1935 PCI hotplug to work on systems with the CNB20LE chipset which do
1938 There's no public spec for this chipset, and this functionality
1939 is known to be incomplete.
1941 You should say N unless you know you need this.
1943 source "drivers/pci/pcie/Kconfig"
1945 source "drivers/pci/Kconfig"
1947 # x86_64 have no ISA slots, but can have ISA-style DMA.
1949 bool "ISA-style DMA support" if (X86_64 && EXPERT)
1952 Enables ISA-style DMA support for devices requiring such controllers.
1960 Find out whether you have ISA slots on your motherboard. ISA is the
1961 name of a bus system, i.e. the way the CPU talks to the other stuff
1962 inside your box. Other bus systems are PCI, EISA, MicroChannel
1963 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1964 newer boards don't support it. If you have ISA, say Y, otherwise N.
1970 The Extended Industry Standard Architecture (EISA) bus was
1971 developed as an open alternative to the IBM MicroChannel bus.
1973 The EISA bus provided some of the features of the IBM MicroChannel
1974 bus while maintaining backward compatibility with cards made for
1975 the older ISA bus. The EISA bus saw limited use between 1988 and
1976 1995 when it was made obsolete by the PCI bus.
1978 Say Y here if you are building a kernel for an EISA-based machine.
1982 source "drivers/eisa/Kconfig"
1987 MicroChannel Architecture is found in some IBM PS/2 machines and
1988 laptops. It is a bus system similar to PCI or ISA. See
1989 <file:Documentation/mca.txt> (and especially the web page given
1990 there) before attempting to build an MCA bus kernel.
1992 source "drivers/mca/Kconfig"
1995 tristate "NatSemi SCx200 support"
1997 This provides basic support for National Semiconductor's
1998 (now AMD's) Geode processors. The driver probes for the
1999 PCI-IDs of several on-chip devices, so its a good dependency
2000 for other scx200_* drivers.
2002 If compiled as a module, the driver is named scx200.
2004 config SCx200HR_TIMER
2005 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2009 This driver provides a clocksource built upon the on-chip
2010 27MHz high-resolution timer. Its also a workaround for
2011 NSC Geode SC-1100's buggy TSC, which loses time when the
2012 processor goes idle (as is done by the scheduler). The
2013 other workaround is idle=poll boot option.
2016 bool "One Laptop Per Child support"
2022 Add support for detecting the unique features of the OLPC
2026 bool "OLPC XO-1 Power Management"
2027 depends on OLPC && MFD_CS5535 && PM_SLEEP
2030 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2033 bool "OLPC XO-1 Real Time Clock"
2034 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2036 Add support for the XO-1 real time clock, which can be used as a
2037 programmable wakeup source.
2040 bool "OLPC XO-1 SCI extras"
2041 depends on OLPC && OLPC_XO1_PM
2046 Add support for SCI-based features of the OLPC XO-1 laptop:
2047 - EC-driven system wakeups
2051 - AC adapter status updates
2052 - Battery status updates
2054 config OLPC_XO15_SCI
2055 bool "OLPC XO-1.5 SCI extras"
2056 depends on OLPC && ACPI
2059 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2060 - EC-driven system wakeups
2061 - AC adapter status updates
2062 - Battery status updates
2068 depends on CPU_SUP_AMD && PCI
2070 source "drivers/pcmcia/Kconfig"
2072 source "drivers/pci/hotplug/Kconfig"
2075 bool "RapidIO support"
2079 If you say Y here, the kernel will include drivers and
2080 infrastructure code to support RapidIO interconnect devices.
2082 source "drivers/rapidio/Kconfig"
2087 menu "Executable file formats / Emulations"
2089 source "fs/Kconfig.binfmt"
2091 config IA32_EMULATION
2092 bool "IA32 Emulation"
2094 select COMPAT_BINFMT_ELF
2096 Include code to run 32-bit programs under a 64-bit kernel. You should
2097 likely turn this on, unless you're 100% sure that you don't have any
2098 32-bit programs left.
2101 tristate "IA32 a.out support"
2102 depends on IA32_EMULATION
2104 Support old a.out binaries in the 32bit emulation.
2108 depends on IA32_EMULATION
2110 config COMPAT_FOR_U64_ALIGNMENT
2114 config SYSVIPC_COMPAT
2116 depends on COMPAT && SYSVIPC
2120 depends on COMPAT && KEYS
2126 config HAVE_ATOMIC_IOMAP
2130 config HAVE_TEXT_POKE_SMP
2132 select STOP_MACHINE if SMP
2134 source "net/Kconfig"
2136 source "drivers/Kconfig"
2138 source "drivers/firmware/Kconfig"
2142 source "arch/x86/Kconfig.debug"
2144 source "security/Kconfig"
2146 source "crypto/Kconfig"
2148 source "arch/x86/kvm/Kconfig"
2150 source "lib/Kconfig"