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_PERF_EVENTS
25 select HAVE_IOREMAP_PROT
28 select ARCH_WANT_OPTIONAL_GPIOLIB
29 select ARCH_WANT_FRAME_POINTERS
31 select HAVE_KRETPROBES
33 select HAVE_FTRACE_MCOUNT_RECORD
34 select HAVE_C_RECORDMCOUNT
35 select HAVE_DYNAMIC_FTRACE
36 select HAVE_FUNCTION_TRACER
37 select HAVE_FUNCTION_GRAPH_TRACER
38 select HAVE_FUNCTION_GRAPH_FP_TEST
39 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
40 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
41 select HAVE_SYSCALL_TRACEPOINTS
44 select HAVE_ARCH_TRACEHOOK
45 select HAVE_GENERIC_DMA_COHERENT if X86_32
46 select HAVE_EFFICIENT_UNALIGNED_ACCESS
47 select USER_STACKTRACE_SUPPORT
48 select HAVE_REGS_AND_STACK_ACCESS_API
49 select HAVE_DMA_API_DEBUG
50 select HAVE_KERNEL_GZIP
51 select HAVE_KERNEL_BZIP2
52 select HAVE_KERNEL_LZMA
54 select HAVE_KERNEL_LZO
55 select HAVE_HW_BREAKPOINT
56 select HAVE_MIXED_BREAKPOINTS_REGS
58 select HAVE_PERF_EVENTS_NMI
60 select HAVE_ARCH_KMEMCHECK
61 select HAVE_USER_RETURN_NOTIFIER
62 select HAVE_ARCH_JUMP_LABEL
63 select HAVE_TEXT_POKE_SMP
64 select HAVE_GENERIC_HARDIRQS
65 select HAVE_SPARSE_IRQ
66 select GENERIC_FIND_FIRST_BIT
67 select GENERIC_IRQ_PROBE
68 select GENERIC_PENDING_IRQ if SMP
69 select GENERIC_IRQ_SHOW
70 select IRQ_FORCED_THREADING
71 select USE_GENERIC_SMP_HELPERS if SMP
72 select HAVE_BPF_JIT if (X86_64 && NET)
74 config INSTRUCTION_DECODER
75 def_bool (KPROBES || PERF_EVENTS)
79 default "elf32-i386" if X86_32
80 default "elf64-x86-64" if X86_64
84 default "arch/x86/configs/i386_defconfig" if X86_32
85 default "arch/x86/configs/x86_64_defconfig" if X86_64
87 config GENERIC_CMOS_UPDATE
90 config CLOCKSOURCE_WATCHDOG
93 config GENERIC_CLOCKEVENTS
96 config GENERIC_CLOCKEVENTS_BROADCAST
98 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
100 config LOCKDEP_SUPPORT
103 config STACKTRACE_SUPPORT
106 config HAVE_LATENCYTOP_SUPPORT
113 bool "DMA memory allocation support" if EXPERT
116 DMA memory allocation support allows devices with less than 32-bit
117 addressing to allocate within the first 16MB of address space.
118 Disable if no such devices will be used.
125 config NEED_DMA_MAP_STATE
126 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
128 config NEED_SG_DMA_LENGTH
131 config GENERIC_ISA_DMA
140 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
142 config GENERIC_BUG_RELATIVE_POINTERS
145 config GENERIC_HWEIGHT
151 config ARCH_MAY_HAVE_PC_FDC
154 config RWSEM_GENERIC_SPINLOCK
157 config RWSEM_XCHGADD_ALGORITHM
160 config ARCH_HAS_CPU_IDLE_WAIT
163 config GENERIC_CALIBRATE_DELAY
166 config GENERIC_TIME_VSYSCALL
170 config ARCH_HAS_CPU_RELAX
173 config ARCH_HAS_DEFAULT_IDLE
176 config ARCH_HAS_CACHE_LINE_SIZE
179 config HAVE_SETUP_PER_CPU_AREA
182 config NEED_PER_CPU_EMBED_FIRST_CHUNK
185 config NEED_PER_CPU_PAGE_FIRST_CHUNK
188 config HAVE_CPUMASK_OF_CPU_MAP
191 config ARCH_HIBERNATION_POSSIBLE
194 config ARCH_SUSPEND_POSSIBLE
201 config ARCH_POPULATES_NODE_MAP
208 config ARCH_SUPPORTS_OPTIMIZED_INLINING
211 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
214 config HAVE_INTEL_TXT
216 depends on EXPERIMENTAL && DMAR && ACPI
220 depends on X86_32 && SMP
224 depends on X86_64 && SMP
230 config X86_32_LAZY_GS
232 depends on X86_32 && !CC_STACKPROTECTOR
234 config ARCH_HWEIGHT_CFLAGS
236 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
237 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
242 config ARCH_CPU_PROBE_RELEASE
244 depends on HOTPLUG_CPU
246 source "init/Kconfig"
247 source "kernel/Kconfig.freezer"
249 menu "Processor type and features"
251 source "kernel/time/Kconfig"
254 bool "Symmetric multi-processing support"
256 This enables support for systems with more than one CPU. If you have
257 a system with only one CPU, like most personal computers, say N. If
258 you have a system with more than one CPU, say Y.
260 If you say N here, the kernel will run on single and multiprocessor
261 machines, but will use only one CPU of a multiprocessor machine. If
262 you say Y here, the kernel will run on many, but not all,
263 singleprocessor machines. On a singleprocessor machine, the kernel
264 will run faster if you say N here.
266 Note that if you say Y here and choose architecture "586" or
267 "Pentium" under "Processor family", the kernel will not work on 486
268 architectures. Similarly, multiprocessor kernels for the "PPro"
269 architecture may not work on all Pentium based boards.
271 People using multiprocessor machines who say Y here should also say
272 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
273 Management" code will be disabled if you say Y here.
275 See also <file:Documentation/i386/IO-APIC.txt>,
276 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
277 <http://www.tldp.org/docs.html#howto>.
279 If you don't know what to do here, say N.
282 bool "Support x2apic"
283 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
285 This enables x2apic support on CPUs that have this feature.
287 This allows 32-bit apic IDs (so it can support very large systems),
288 and accesses the local apic via MSRs not via mmio.
290 If you don't know what to do here, say N.
293 bool "Enable MPS table" if ACPI
295 depends on X86_LOCAL_APIC
297 For old smp systems that do not have proper acpi support. Newer systems
298 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
301 bool "Support for big SMP systems with more than 8 CPUs"
302 depends on X86_32 && SMP
304 This option is needed for the systems that have more than 8 CPUs
307 config X86_EXTENDED_PLATFORM
308 bool "Support for extended (non-PC) x86 platforms"
311 If you disable this option then the kernel will only support
312 standard PC platforms. (which covers the vast majority of
315 If you enable this option then you'll be able to select support
316 for the following (non-PC) 32 bit x86 platforms:
320 SGI 320/540 (Visual Workstation)
321 Summit/EXA (IBM x440)
322 Unisys ES7000 IA32 series
323 Moorestown MID devices
325 If you have one of these systems, or if you want to build a
326 generic distribution kernel, say Y here - otherwise say N.
330 config X86_EXTENDED_PLATFORM
331 bool "Support for extended (non-PC) x86 platforms"
334 If you disable this option then the kernel will only support
335 standard PC platforms. (which covers the vast majority of
338 If you enable this option then you'll be able to select support
339 for the following (non-PC) 64 bit x86 platforms:
343 If you have one of these systems, or if you want to build a
344 generic distribution kernel, say Y here - otherwise say N.
346 # This is an alphabetically sorted list of 64 bit extended platforms
347 # Please maintain the alphabetic order if and when there are additions
351 select PARAVIRT_GUEST
353 depends on X86_64 && PCI
354 depends on X86_EXTENDED_PLATFORM
356 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
357 supposed to run on these EM64T-based machines. Only choose this option
358 if you have one of these machines.
361 bool "SGI Ultraviolet"
363 depends on X86_EXTENDED_PLATFORM
365 depends on X86_X2APIC
367 This option is needed in order to support SGI Ultraviolet systems.
368 If you don't have one of these, you should say N here.
370 # Following is an alphabetically sorted list of 32 bit extended platforms
371 # Please maintain the alphabetic order if and when there are additions
374 bool "CE4100 TV platform"
376 depends on PCI_GODIRECT
378 depends on X86_EXTENDED_PLATFORM
379 select X86_REBOOTFIXUPS
381 select OF_EARLY_FLATTREE
383 Select for the Intel CE media processor (CE4100) SOC.
384 This option compiles in support for the CE4100 SOC for settop
385 boxes and media devices.
388 bool "Moorestown MID platform"
392 depends on X86_EXTENDED_PLATFORM
393 depends on X86_IO_APIC
398 select X86_PLATFORM_DEVICES
400 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
401 Internet Device(MID) platform. Moorestown consists of two chips:
402 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
403 Unlike standard x86 PCs, Moorestown does not have many legacy devices
404 nor standard legacy replacement devices/features. e.g. Moorestown does
405 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
408 bool "RDC R-321x SoC"
410 depends on X86_EXTENDED_PLATFORM
412 select X86_REBOOTFIXUPS
414 This option is needed for RDC R-321x system-on-chip, also known
416 If you don't have one of these chips, you should say N here.
418 config X86_32_NON_STANDARD
419 bool "Support non-standard 32-bit SMP architectures"
420 depends on X86_32 && SMP
421 depends on X86_EXTENDED_PLATFORM
423 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
424 subarchitectures. It is intended for a generic binary kernel.
425 if you select them all, kernel will probe it one by one. and will
428 # Alphabetically sorted list of Non standard 32 bit platforms
431 bool "NUMAQ (IBM/Sequent)"
432 depends on X86_32_NON_STANDARD
437 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
438 NUMA multiquad box. This changes the way that processors are
439 bootstrapped, and uses Clustered Logical APIC addressing mode instead
440 of Flat Logical. You will need a new lynxer.elf file to flash your
441 firmware with - send email to <Martin.Bligh@us.ibm.com>.
443 config X86_SUPPORTS_MEMORY_FAILURE
445 # MCE code calls memory_failure():
447 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
448 depends on !X86_NUMAQ
449 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
450 depends on X86_64 || !SPARSEMEM
451 select ARCH_SUPPORTS_MEMORY_FAILURE
454 bool "SGI 320/540 (Visual Workstation)"
455 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
456 depends on X86_32_NON_STANDARD
458 The SGI Visual Workstation series is an IA32-based workstation
459 based on SGI systems chips with some legacy PC hardware attached.
461 Say Y here to create a kernel to run on the SGI 320 or 540.
463 A kernel compiled for the Visual Workstation will run on general
464 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
467 bool "Summit/EXA (IBM x440)"
468 depends on X86_32_NON_STANDARD
470 This option is needed for IBM systems that use the Summit/EXA chipset.
471 In particular, it is needed for the x440.
474 bool "Unisys ES7000 IA32 series"
475 depends on X86_32_NON_STANDARD && X86_BIGSMP
477 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
478 supposed to run on an IA32-based Unisys ES7000 system.
481 tristate "Eurobraille/Iris poweroff module"
484 The Iris machines from EuroBraille do not have APM or ACPI support
485 to shut themselves down properly. A special I/O sequence is
486 needed to do so, which is what this module does at
489 This is only for Iris machines from EuroBraille.
493 config SCHED_OMIT_FRAME_POINTER
495 prompt "Single-depth WCHAN output"
498 Calculate simpler /proc/<PID>/wchan values. If this option
499 is disabled then wchan values will recurse back to the
500 caller function. This provides more accurate wchan values,
501 at the expense of slightly more scheduling overhead.
503 If in doubt, say "Y".
505 menuconfig PARAVIRT_GUEST
506 bool "Paravirtualized guest support"
508 Say Y here to get to see options related to running Linux under
509 various hypervisors. This option alone does not add any kernel code.
511 If you say N, all options in this submenu will be skipped and disabled.
515 config PARAVIRT_TIME_ACCOUNTING
516 bool "Paravirtual steal time accounting"
520 Select this option to enable fine granularity task steal time
521 accounting. Time spent executing other tasks in parallel with
522 the current vCPU is discounted from the vCPU power. To account for
523 that, there can be a small performance impact.
525 If in doubt, say N here.
527 source "arch/x86/xen/Kconfig"
530 bool "KVM paravirtualized clock"
532 select PARAVIRT_CLOCK
534 Turning on this option will allow you to run a paravirtualized clock
535 when running over the KVM hypervisor. Instead of relying on a PIT
536 (or probably other) emulation by the underlying device model, the host
537 provides the guest with timing infrastructure such as time of day, and
541 bool "KVM Guest support"
544 This option enables various optimizations for running under the KVM
547 source "arch/x86/lguest/Kconfig"
550 bool "Enable paravirtualization code"
552 This changes the kernel so it can modify itself when it is run
553 under a hypervisor, potentially improving performance significantly
554 over full virtualization. However, when run without a hypervisor
555 the kernel is theoretically slower and slightly larger.
557 config PARAVIRT_SPINLOCKS
558 bool "Paravirtualization layer for spinlocks"
559 depends on PARAVIRT && SMP && EXPERIMENTAL
561 Paravirtualized spinlocks allow a pvops backend to replace the
562 spinlock implementation with something virtualization-friendly
563 (for example, block the virtual CPU rather than spinning).
565 Unfortunately the downside is an up to 5% performance hit on
566 native kernels, with various workloads.
568 If you are unsure how to answer this question, answer N.
570 config PARAVIRT_CLOCK
575 config PARAVIRT_DEBUG
576 bool "paravirt-ops debugging"
577 depends on PARAVIRT && DEBUG_KERNEL
579 Enable to debug paravirt_ops internals. Specifically, BUG if
580 a paravirt_op is missing when it is called.
588 This option adds a kernel parameter 'memtest', which allows memtest
590 memtest=0, mean disabled; -- default
591 memtest=1, mean do 1 test pattern;
593 memtest=4, mean do 4 test patterns.
594 If you are unsure how to answer this question, answer N.
596 config X86_SUMMIT_NUMA
598 depends on X86_32 && NUMA && X86_32_NON_STANDARD
600 config X86_CYCLONE_TIMER
602 depends on X86_32_NON_STANDARD
604 source "arch/x86/Kconfig.cpu"
608 prompt "HPET Timer Support" if X86_32
610 Use the IA-PC HPET (High Precision Event Timer) to manage
611 time in preference to the PIT and RTC, if a HPET is
613 HPET is the next generation timer replacing legacy 8254s.
614 The HPET provides a stable time base on SMP
615 systems, unlike the TSC, but it is more expensive to access,
616 as it is off-chip. You can find the HPET spec at
617 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
619 You can safely choose Y here. However, HPET will only be
620 activated if the platform and the BIOS support this feature.
621 Otherwise the 8254 will be used for timing services.
623 Choose N to continue using the legacy 8254 timer.
625 config HPET_EMULATE_RTC
627 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
631 prompt "Langwell APB Timer Support" if X86_MRST
633 APB timer is the replacement for 8254, HPET on X86 MID platforms.
634 The APBT provides a stable time base on SMP
635 systems, unlike the TSC, but it is more expensive to access,
636 as it is off-chip. APB timers are always running regardless of CPU
637 C states, they are used as per CPU clockevent device when possible.
639 # Mark as expert because too many people got it wrong.
640 # The code disables itself when not needed.
643 bool "Enable DMI scanning" if EXPERT
645 Enabled scanning of DMI to identify machine quirks. Say Y
646 here unless you have verified that your setup is not
647 affected by entries in the DMI blacklist. Required by PNP
651 bool "GART IOMMU support" if EXPERT
654 depends on X86_64 && PCI && AMD_NB
656 Support for full DMA access of devices with 32bit memory access only
657 on systems with more than 3GB. This is usually needed for USB,
658 sound, many IDE/SATA chipsets and some other devices.
659 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
660 based hardware IOMMU and a software bounce buffer based IOMMU used
661 on Intel systems and as fallback.
662 The code is only active when needed (enough memory and limited
663 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
667 bool "IBM Calgary IOMMU support"
669 depends on X86_64 && PCI && EXPERIMENTAL
671 Support for hardware IOMMUs in IBM's xSeries x366 and x460
672 systems. Needed to run systems with more than 3GB of memory
673 properly with 32-bit PCI devices that do not support DAC
674 (Double Address Cycle). Calgary also supports bus level
675 isolation, where all DMAs pass through the IOMMU. This
676 prevents them from going anywhere except their intended
677 destination. This catches hard-to-find kernel bugs and
678 mis-behaving drivers and devices that do not use the DMA-API
679 properly to set up their DMA buffers. The IOMMU can be
680 turned off at boot time with the iommu=off parameter.
681 Normally the kernel will make the right choice by itself.
684 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
686 prompt "Should Calgary be enabled by default?"
687 depends on CALGARY_IOMMU
689 Should Calgary be enabled by default? if you choose 'y', Calgary
690 will be used (if it exists). If you choose 'n', Calgary will not be
691 used even if it exists. If you choose 'n' and would like to use
692 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
696 bool "AMD IOMMU support"
700 depends on X86_64 && PCI && ACPI
702 With this option you can enable support for AMD IOMMU hardware in
703 your system. An IOMMU is a hardware component which provides
704 remapping of DMA memory accesses from devices. With an AMD IOMMU you
705 can isolate the the DMA memory of different devices and protect the
706 system from misbehaving device drivers or hardware.
708 You can find out if your system has an AMD IOMMU if you look into
709 your BIOS for an option to enable it or if you have an IVRS ACPI
712 config AMD_IOMMU_STATS
713 bool "Export AMD IOMMU statistics to debugfs"
717 This option enables code in the AMD IOMMU driver to collect various
718 statistics about whats happening in the driver and exports that
719 information to userspace via debugfs.
722 # need this always selected by IOMMU for the VIA workaround
726 Support for software bounce buffers used on x86-64 systems
727 which don't have a hardware IOMMU (e.g. the current generation
728 of Intel's x86-64 CPUs). Using this PCI devices which can only
729 access 32-bits of memory can be used on systems with more than
730 3 GB of memory. If unsure, say Y.
733 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
736 def_bool (AMD_IOMMU || DMAR)
739 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
740 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
741 select CPUMASK_OFFSTACK
743 Enable maximum number of CPUS and NUMA Nodes for this architecture.
747 int "Maximum number of CPUs" if SMP && !MAXSMP
748 range 2 8 if SMP && X86_32 && !X86_BIGSMP
749 range 2 512 if SMP && !MAXSMP
751 default "4096" if MAXSMP
752 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
755 This allows you to specify the maximum number of CPUs which this
756 kernel will support. The maximum supported value is 512 and the
757 minimum value which makes sense is 2.
759 This is purely to save memory - each supported CPU adds
760 approximately eight kilobytes to the kernel image.
763 bool "SMT (Hyperthreading) scheduler support"
766 SMT scheduler support improves the CPU scheduler's decision making
767 when dealing with Intel Pentium 4 chips with HyperThreading at a
768 cost of slightly increased overhead in some places. If unsure say
773 prompt "Multi-core scheduler support"
776 Multi-core scheduler support improves the CPU scheduler's decision
777 making when dealing with multi-core CPU chips at a cost of slightly
778 increased overhead in some places. If unsure say N here.
780 config IRQ_TIME_ACCOUNTING
781 bool "Fine granularity task level IRQ time accounting"
784 Select this option to enable fine granularity task irq time
785 accounting. This is done by reading a timestamp on each
786 transitions between softirq and hardirq state, so there can be a
787 small performance impact.
789 If in doubt, say N here.
791 source "kernel/Kconfig.preempt"
794 bool "Local APIC support on uniprocessors"
795 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
797 A local APIC (Advanced Programmable Interrupt Controller) is an
798 integrated interrupt controller in the CPU. If you have a single-CPU
799 system which has a processor with a local APIC, you can say Y here to
800 enable and use it. If you say Y here even though your machine doesn't
801 have a local APIC, then the kernel will still run with no slowdown at
802 all. The local APIC supports CPU-generated self-interrupts (timer,
803 performance counters), and the NMI watchdog which detects hard
807 bool "IO-APIC support on uniprocessors"
808 depends on X86_UP_APIC
810 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
811 SMP-capable replacement for PC-style interrupt controllers. Most
812 SMP systems and many recent uniprocessor systems have one.
814 If you have a single-CPU system with an IO-APIC, you can say Y here
815 to use it. If you say Y here even though your machine doesn't have
816 an IO-APIC, then the kernel will still run with no slowdown at all.
818 config X86_LOCAL_APIC
820 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
824 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
826 config X86_VISWS_APIC
828 depends on X86_32 && X86_VISWS
830 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
831 bool "Reroute for broken boot IRQs"
832 depends on X86_IO_APIC
834 This option enables a workaround that fixes a source of
835 spurious interrupts. This is recommended when threaded
836 interrupt handling is used on systems where the generation of
837 superfluous "boot interrupts" cannot be disabled.
839 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
840 entry in the chipset's IO-APIC is masked (as, e.g. the RT
841 kernel does during interrupt handling). On chipsets where this
842 boot IRQ generation cannot be disabled, this workaround keeps
843 the original IRQ line masked so that only the equivalent "boot
844 IRQ" is delivered to the CPUs. The workaround also tells the
845 kernel to set up the IRQ handler on the boot IRQ line. In this
846 way only one interrupt is delivered to the kernel. Otherwise
847 the spurious second interrupt may cause the kernel to bring
848 down (vital) interrupt lines.
850 Only affects "broken" chipsets. Interrupt sharing may be
851 increased on these systems.
854 bool "Machine Check / overheating reporting"
856 Machine Check support allows the processor to notify the
857 kernel if it detects a problem (e.g. overheating, data corruption).
858 The action the kernel takes depends on the severity of the problem,
859 ranging from warning messages to halting the machine.
863 prompt "Intel MCE features"
864 depends on X86_MCE && X86_LOCAL_APIC
866 Additional support for intel specific MCE features such as
871 prompt "AMD MCE features"
872 depends on X86_MCE && X86_LOCAL_APIC
874 Additional support for AMD specific MCE features such as
875 the DRAM Error Threshold.
877 config X86_ANCIENT_MCE
878 bool "Support for old Pentium 5 / WinChip machine checks"
879 depends on X86_32 && X86_MCE
881 Include support for machine check handling on old Pentium 5 or WinChip
882 systems. These typically need to be enabled explicitely on the command
885 config X86_MCE_THRESHOLD
886 depends on X86_MCE_AMD || X86_MCE_INTEL
889 config X86_MCE_INJECT
891 tristate "Machine check injector support"
893 Provide support for injecting machine checks for testing purposes.
894 If you don't know what a machine check is and you don't do kernel
895 QA it is safe to say n.
897 config X86_THERMAL_VECTOR
899 depends on X86_MCE_INTEL
902 bool "Enable VM86 support" if EXPERT
906 This option is required by programs like DOSEMU to run 16-bit legacy
907 code on X86 processors. It also may be needed by software like
908 XFree86 to initialize some video cards via BIOS. Disabling this
909 option saves about 6k.
912 tristate "Toshiba Laptop support"
915 This adds a driver to safely access the System Management Mode of
916 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
917 not work on models with a Phoenix BIOS. The System Management Mode
918 is used to set the BIOS and power saving options on Toshiba portables.
920 For information on utilities to make use of this driver see the
921 Toshiba Linux utilities web site at:
922 <http://www.buzzard.org.uk/toshiba/>.
924 Say Y if you intend to run this kernel on a Toshiba portable.
928 tristate "Dell laptop support"
931 This adds a driver to safely access the System Management Mode
932 of the CPU on the Dell Inspiron 8000. The System Management Mode
933 is used to read cpu temperature and cooling fan status and to
934 control the fans on the I8K portables.
936 This driver has been tested only on the Inspiron 8000 but it may
937 also work with other Dell laptops. You can force loading on other
938 models by passing the parameter `force=1' to the module. Use at
941 For information on utilities to make use of this driver see the
942 I8K Linux utilities web site at:
943 <http://people.debian.org/~dz/i8k/>
945 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
948 config X86_REBOOTFIXUPS
949 bool "Enable X86 board specific fixups for reboot"
952 This enables chipset and/or board specific fixups to be done
953 in order to get reboot to work correctly. This is only needed on
954 some combinations of hardware and BIOS. The symptom, for which
955 this config is intended, is when reboot ends with a stalled/hung
958 Currently, the only fixup is for the Geode machines using
959 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
961 Say Y if you want to enable the fixup. Currently, it's safe to
962 enable this option even if you don't need it.
966 tristate "/dev/cpu/microcode - microcode support"
969 If you say Y here, you will be able to update the microcode on
970 certain Intel and AMD processors. The Intel support is for the
971 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
972 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
973 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
974 You will obviously need the actual microcode binary data itself
975 which is not shipped with the Linux kernel.
977 This option selects the general module only, you need to select
978 at least one vendor specific module as well.
980 To compile this driver as a module, choose M here: the
981 module will be called microcode.
983 config MICROCODE_INTEL
984 bool "Intel microcode patch loading support"
989 This options enables microcode patch loading support for Intel
992 For latest news and information on obtaining all the required
993 Intel ingredients for this driver, check:
994 <http://www.urbanmyth.org/microcode/>.
997 bool "AMD microcode patch loading support"
1001 If you select this option, microcode patch loading support for AMD
1002 processors will be enabled.
1004 config MICROCODE_OLD_INTERFACE
1006 depends on MICROCODE
1009 tristate "/dev/cpu/*/msr - Model-specific register support"
1011 This device gives privileged processes access to the x86
1012 Model-Specific Registers (MSRs). It is a character device with
1013 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1014 MSR accesses are directed to a specific CPU on multi-processor
1018 tristate "/dev/cpu/*/cpuid - CPU information support"
1020 This device gives processes access to the x86 CPUID instruction to
1021 be executed on a specific processor. It is a character device
1022 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1026 prompt "High Memory Support"
1027 default HIGHMEM64G if X86_NUMAQ
1033 depends on !X86_NUMAQ
1035 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1036 However, the address space of 32-bit x86 processors is only 4
1037 Gigabytes large. That means that, if you have a large amount of
1038 physical memory, not all of it can be "permanently mapped" by the
1039 kernel. The physical memory that's not permanently mapped is called
1042 If you are compiling a kernel which will never run on a machine with
1043 more than 1 Gigabyte total physical RAM, answer "off" here (default
1044 choice and suitable for most users). This will result in a "3GB/1GB"
1045 split: 3GB are mapped so that each process sees a 3GB virtual memory
1046 space and the remaining part of the 4GB virtual memory space is used
1047 by the kernel to permanently map as much physical memory as
1050 If the machine has between 1 and 4 Gigabytes physical RAM, then
1053 If more than 4 Gigabytes is used then answer "64GB" here. This
1054 selection turns Intel PAE (Physical Address Extension) mode on.
1055 PAE implements 3-level paging on IA32 processors. PAE is fully
1056 supported by Linux, PAE mode is implemented on all recent Intel
1057 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1058 then the kernel will not boot on CPUs that don't support PAE!
1060 The actual amount of total physical memory will either be
1061 auto detected or can be forced by using a kernel command line option
1062 such as "mem=256M". (Try "man bootparam" or see the documentation of
1063 your boot loader (lilo or loadlin) about how to pass options to the
1064 kernel at boot time.)
1066 If unsure, say "off".
1070 depends on !X86_NUMAQ
1072 Select this if you have a 32-bit processor and between 1 and 4
1073 gigabytes of physical RAM.
1077 depends on !M386 && !M486
1080 Select this if you have a 32-bit processor and more than 4
1081 gigabytes of physical RAM.
1086 depends on EXPERIMENTAL
1087 prompt "Memory split" if EXPERT
1091 Select the desired split between kernel and user memory.
1093 If the address range available to the kernel is less than the
1094 physical memory installed, the remaining memory will be available
1095 as "high memory". Accessing high memory is a little more costly
1096 than low memory, as it needs to be mapped into the kernel first.
1097 Note that increasing the kernel address space limits the range
1098 available to user programs, making the address space there
1099 tighter. Selecting anything other than the default 3G/1G split
1100 will also likely make your kernel incompatible with binary-only
1103 If you are not absolutely sure what you are doing, leave this
1107 bool "3G/1G user/kernel split"
1108 config VMSPLIT_3G_OPT
1110 bool "3G/1G user/kernel split (for full 1G low memory)"
1112 bool "2G/2G user/kernel split"
1113 config VMSPLIT_2G_OPT
1115 bool "2G/2G user/kernel split (for full 2G low memory)"
1117 bool "1G/3G user/kernel split"
1122 default 0xB0000000 if VMSPLIT_3G_OPT
1123 default 0x80000000 if VMSPLIT_2G
1124 default 0x78000000 if VMSPLIT_2G_OPT
1125 default 0x40000000 if VMSPLIT_1G
1131 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1134 bool "PAE (Physical Address Extension) Support"
1135 depends on X86_32 && !HIGHMEM4G
1137 PAE is required for NX support, and furthermore enables
1138 larger swapspace support for non-overcommit purposes. It
1139 has the cost of more pagetable lookup overhead, and also
1140 consumes more pagetable space per process.
1142 config ARCH_PHYS_ADDR_T_64BIT
1143 def_bool X86_64 || X86_PAE
1145 config ARCH_DMA_ADDR_T_64BIT
1146 def_bool X86_64 || HIGHMEM64G
1148 config DIRECT_GBPAGES
1149 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1153 Allow the kernel linear mapping to use 1GB pages on CPUs that
1154 support it. This can improve the kernel's performance a tiny bit by
1155 reducing TLB pressure. If in doubt, say "Y".
1157 # Common NUMA Features
1159 bool "Numa Memory Allocation and Scheduler Support"
1161 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1162 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1164 Enable NUMA (Non Uniform Memory Access) support.
1166 The kernel will try to allocate memory used by a CPU on the
1167 local memory controller of the CPU and add some more
1168 NUMA awareness to the kernel.
1170 For 64-bit this is recommended if the system is Intel Core i7
1171 (or later), AMD Opteron, or EM64T NUMA.
1173 For 32-bit this is only needed on (rare) 32-bit-only platforms
1174 that support NUMA topologies, such as NUMAQ / Summit, or if you
1175 boot a 32-bit kernel on a 64-bit NUMA platform.
1177 Otherwise, you should say N.
1179 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1180 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1184 prompt "Old style AMD Opteron NUMA detection"
1185 depends on NUMA && PCI
1187 Enable AMD NUMA node topology detection. You should say Y here if
1188 you have a multi processor AMD system. This uses an old method to
1189 read the NUMA configuration directly from the builtin Northbridge
1190 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1191 which also takes priority if both are compiled in.
1193 config X86_64_ACPI_NUMA
1195 prompt "ACPI NUMA detection"
1196 depends on X86_64 && NUMA && ACPI && PCI
1199 Enable ACPI SRAT based node topology detection.
1201 # Some NUMA nodes have memory ranges that span
1202 # other nodes. Even though a pfn is valid and
1203 # between a node's start and end pfns, it may not
1204 # reside on that node. See memmap_init_zone()
1206 config NODES_SPAN_OTHER_NODES
1208 depends on X86_64_ACPI_NUMA
1211 bool "NUMA emulation"
1214 Enable NUMA emulation. A flat machine will be split
1215 into virtual nodes when booted with "numa=fake=N", where N is the
1216 number of nodes. This is only useful for debugging.
1219 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1221 default "10" if MAXSMP
1222 default "6" if X86_64
1223 default "4" if X86_NUMAQ
1225 depends on NEED_MULTIPLE_NODES
1227 Specify the maximum number of NUMA Nodes available on the target
1228 system. Increases memory reserved to accommodate various tables.
1230 config HAVE_ARCH_BOOTMEM
1232 depends on X86_32 && NUMA
1234 config HAVE_ARCH_ALLOC_REMAP
1236 depends on X86_32 && NUMA
1238 config ARCH_HAVE_MEMORY_PRESENT
1240 depends on X86_32 && DISCONTIGMEM
1242 config NEED_NODE_MEMMAP_SIZE
1244 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1246 config ARCH_FLATMEM_ENABLE
1248 depends on X86_32 && !NUMA
1250 config ARCH_DISCONTIGMEM_ENABLE
1252 depends on NUMA && X86_32
1254 config ARCH_DISCONTIGMEM_DEFAULT
1256 depends on NUMA && X86_32
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_SPARSEMEM_DEFAULT
1268 config ARCH_SELECT_MEMORY_MODEL
1270 depends on ARCH_SPARSEMEM_ENABLE
1272 config ARCH_MEMORY_PROBE
1274 depends on MEMORY_HOTPLUG
1276 config ARCH_PROC_KCORE_TEXT
1278 depends on X86_64 && PROC_KCORE
1280 config ILLEGAL_POINTER_VALUE
1283 default 0xdead000000000000 if X86_64
1288 bool "Allocate 3rd-level pagetables from highmem"
1291 The VM uses one page table entry for each page of physical memory.
1292 For systems with a lot of RAM, this can be wasteful of precious
1293 low memory. Setting this option will put user-space page table
1294 entries in high memory.
1296 config X86_CHECK_BIOS_CORRUPTION
1297 bool "Check for low memory corruption"
1299 Periodically check for memory corruption in low memory, which
1300 is suspected to be caused by BIOS. Even when enabled in the
1301 configuration, it is disabled at runtime. Enable it by
1302 setting "memory_corruption_check=1" on the kernel command
1303 line. By default it scans the low 64k of memory every 60
1304 seconds; see the memory_corruption_check_size and
1305 memory_corruption_check_period parameters in
1306 Documentation/kernel-parameters.txt to adjust this.
1308 When enabled with the default parameters, this option has
1309 almost no overhead, as it reserves a relatively small amount
1310 of memory and scans it infrequently. It both detects corruption
1311 and prevents it from affecting the running system.
1313 It is, however, intended as a diagnostic tool; if repeatable
1314 BIOS-originated corruption always affects the same memory,
1315 you can use memmap= to prevent the kernel from using that
1318 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1319 bool "Set the default setting of memory_corruption_check"
1320 depends on X86_CHECK_BIOS_CORRUPTION
1323 Set whether the default state of memory_corruption_check is
1326 config X86_RESERVE_LOW
1327 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1331 Specify the amount of low memory to reserve for the BIOS.
1333 The first page contains BIOS data structures that the kernel
1334 must not use, so that page must always be reserved.
1336 By default we reserve the first 64K of physical RAM, as a
1337 number of BIOSes are known to corrupt that memory range
1338 during events such as suspend/resume or monitor cable
1339 insertion, so it must not be used by the kernel.
1341 You can set this to 4 if you are absolutely sure that you
1342 trust the BIOS to get all its memory reservations and usages
1343 right. If you know your BIOS have problems beyond the
1344 default 64K area, you can set this to 640 to avoid using the
1345 entire low memory range.
1347 If you have doubts about the BIOS (e.g. suspend/resume does
1348 not work or there's kernel crashes after certain hardware
1349 hotplug events) then you might want to enable
1350 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1351 typical corruption patterns.
1353 Leave this to the default value of 64 if you are unsure.
1355 config MATH_EMULATION
1357 prompt "Math emulation" if X86_32
1359 Linux can emulate a math coprocessor (used for floating point
1360 operations) if you don't have one. 486DX and Pentium processors have
1361 a math coprocessor built in, 486SX and 386 do not, unless you added
1362 a 487DX or 387, respectively. (The messages during boot time can
1363 give you some hints here ["man dmesg"].) Everyone needs either a
1364 coprocessor or this emulation.
1366 If you don't have a math coprocessor, you need to say Y here; if you
1367 say Y here even though you have a coprocessor, the coprocessor will
1368 be used nevertheless. (This behavior can be changed with the kernel
1369 command line option "no387", which comes handy if your coprocessor
1370 is broken. Try "man bootparam" or see the documentation of your boot
1371 loader (lilo or loadlin) about how to pass options to the kernel at
1372 boot time.) This means that it is a good idea to say Y here if you
1373 intend to use this kernel on different machines.
1375 More information about the internals of the Linux math coprocessor
1376 emulation can be found in <file:arch/x86/math-emu/README>.
1378 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1379 kernel, it won't hurt.
1383 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1385 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1386 the Memory Type Range Registers (MTRRs) may be used to control
1387 processor access to memory ranges. This is most useful if you have
1388 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1389 allows bus write transfers to be combined into a larger transfer
1390 before bursting over the PCI/AGP bus. This can increase performance
1391 of image write operations 2.5 times or more. Saying Y here creates a
1392 /proc/mtrr file which may be used to manipulate your processor's
1393 MTRRs. Typically the X server should use this.
1395 This code has a reasonably generic interface so that similar
1396 control registers on other processors can be easily supported
1399 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1400 Registers (ARRs) which provide a similar functionality to MTRRs. For
1401 these, the ARRs are used to emulate the MTRRs.
1402 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1403 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1404 write-combining. All of these processors are supported by this code
1405 and it makes sense to say Y here if you have one of them.
1407 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1408 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1409 can lead to all sorts of problems, so it's good to say Y here.
1411 You can safely say Y even if your machine doesn't have MTRRs, you'll
1412 just add about 9 KB to your kernel.
1414 See <file:Documentation/x86/mtrr.txt> for more information.
1416 config MTRR_SANITIZER
1418 prompt "MTRR cleanup support"
1421 Convert MTRR layout from continuous to discrete, so X drivers can
1422 add writeback entries.
1424 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1425 The largest mtrr entry size for a continuous block can be set with
1430 config MTRR_SANITIZER_ENABLE_DEFAULT
1431 int "MTRR cleanup enable value (0-1)"
1434 depends on MTRR_SANITIZER
1436 Enable mtrr cleanup default value
1438 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1439 int "MTRR cleanup spare reg num (0-7)"
1442 depends on MTRR_SANITIZER
1444 mtrr cleanup spare entries default, it can be changed via
1445 mtrr_spare_reg_nr=N on the kernel command line.
1449 prompt "x86 PAT support" if EXPERT
1452 Use PAT attributes to setup page level cache control.
1454 PATs are the modern equivalents of MTRRs and are much more
1455 flexible than MTRRs.
1457 Say N here if you see bootup problems (boot crash, boot hang,
1458 spontaneous reboots) or a non-working video driver.
1462 config ARCH_USES_PG_UNCACHED
1467 bool "EFI runtime service support"
1470 This enables the kernel to use EFI runtime services that are
1471 available (such as the EFI variable services).
1473 This option is only useful on systems that have EFI firmware.
1474 In addition, you should use the latest ELILO loader available
1475 at <http://elilo.sourceforge.net> in order to take advantage
1476 of EFI runtime services. However, even with this option, the
1477 resultant kernel should continue to boot on existing non-EFI
1482 prompt "Enable seccomp to safely compute untrusted bytecode"
1484 This kernel feature is useful for number crunching applications
1485 that may need to compute untrusted bytecode during their
1486 execution. By using pipes or other transports made available to
1487 the process as file descriptors supporting the read/write
1488 syscalls, it's possible to isolate those applications in
1489 their own address space using seccomp. Once seccomp is
1490 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1491 and the task is only allowed to execute a few safe syscalls
1492 defined by each seccomp mode.
1494 If unsure, say Y. Only embedded should say N here.
1496 config CC_STACKPROTECTOR
1497 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1499 This option turns on the -fstack-protector GCC feature. This
1500 feature puts, at the beginning of functions, a canary value on
1501 the stack just before the return address, and validates
1502 the value just before actually returning. Stack based buffer
1503 overflows (that need to overwrite this return address) now also
1504 overwrite the canary, which gets detected and the attack is then
1505 neutralized via a kernel panic.
1507 This feature requires gcc version 4.2 or above, or a distribution
1508 gcc with the feature backported. Older versions are automatically
1509 detected and for those versions, this configuration option is
1510 ignored. (and a warning is printed during bootup)
1512 source kernel/Kconfig.hz
1515 bool "kexec system call"
1517 kexec is a system call that implements the ability to shutdown your
1518 current kernel, and to start another kernel. It is like a reboot
1519 but it is independent of the system firmware. And like a reboot
1520 you can start any kernel with it, not just Linux.
1522 The name comes from the similarity to the exec system call.
1524 It is an ongoing process to be certain the hardware in a machine
1525 is properly shutdown, so do not be surprised if this code does not
1526 initially work for you. It may help to enable device hotplugging
1527 support. As of this writing the exact hardware interface is
1528 strongly in flux, so no good recommendation can be made.
1531 bool "kernel crash dumps"
1532 depends on X86_64 || (X86_32 && HIGHMEM)
1534 Generate crash dump after being started by kexec.
1535 This should be normally only set in special crash dump kernels
1536 which are loaded in the main kernel with kexec-tools into
1537 a specially reserved region and then later executed after
1538 a crash by kdump/kexec. The crash dump kernel must be compiled
1539 to a memory address not used by the main kernel or BIOS using
1540 PHYSICAL_START, or it must be built as a relocatable image
1541 (CONFIG_RELOCATABLE=y).
1542 For more details see Documentation/kdump/kdump.txt
1545 bool "kexec jump (EXPERIMENTAL)"
1546 depends on EXPERIMENTAL
1547 depends on KEXEC && HIBERNATION
1549 Jump between original kernel and kexeced kernel and invoke
1550 code in physical address mode via KEXEC
1552 config PHYSICAL_START
1553 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1556 This gives the physical address where the kernel is loaded.
1558 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1559 bzImage will decompress itself to above physical address and
1560 run from there. Otherwise, bzImage will run from the address where
1561 it has been loaded by the boot loader and will ignore above physical
1564 In normal kdump cases one does not have to set/change this option
1565 as now bzImage can be compiled as a completely relocatable image
1566 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1567 address. This option is mainly useful for the folks who don't want
1568 to use a bzImage for capturing the crash dump and want to use a
1569 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1570 to be specifically compiled to run from a specific memory area
1571 (normally a reserved region) and this option comes handy.
1573 So if you are using bzImage for capturing the crash dump,
1574 leave the value here unchanged to 0x1000000 and set
1575 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1576 for capturing the crash dump change this value to start of
1577 the reserved region. In other words, it can be set based on
1578 the "X" value as specified in the "crashkernel=YM@XM"
1579 command line boot parameter passed to the panic-ed
1580 kernel. Please take a look at Documentation/kdump/kdump.txt
1581 for more details about crash dumps.
1583 Usage of bzImage for capturing the crash dump is recommended as
1584 one does not have to build two kernels. Same kernel can be used
1585 as production kernel and capture kernel. Above option should have
1586 gone away after relocatable bzImage support is introduced. But it
1587 is present because there are users out there who continue to use
1588 vmlinux for dump capture. This option should go away down the
1591 Don't change this unless you know what you are doing.
1594 bool "Build a relocatable kernel"
1597 This builds a kernel image that retains relocation information
1598 so it can be loaded someplace besides the default 1MB.
1599 The relocations tend to make the kernel binary about 10% larger,
1600 but are discarded at runtime.
1602 One use is for the kexec on panic case where the recovery kernel
1603 must live at a different physical address than the primary
1606 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1607 it has been loaded at and the compile time physical address
1608 (CONFIG_PHYSICAL_START) is ignored.
1610 # Relocation on x86-32 needs some additional build support
1611 config X86_NEED_RELOCS
1613 depends on X86_32 && RELOCATABLE
1615 config PHYSICAL_ALIGN
1616 hex "Alignment value to which kernel should be aligned" if X86_32
1618 range 0x2000 0x1000000
1620 This value puts the alignment restrictions on physical address
1621 where kernel is loaded and run from. Kernel is compiled for an
1622 address which meets above alignment restriction.
1624 If bootloader loads the kernel at a non-aligned address and
1625 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1626 address aligned to above value and run from there.
1628 If bootloader loads the kernel at a non-aligned address and
1629 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1630 load address and decompress itself to the address it has been
1631 compiled for and run from there. The address for which kernel is
1632 compiled already meets above alignment restrictions. Hence the
1633 end result is that kernel runs from a physical address meeting
1634 above alignment restrictions.
1636 Don't change this unless you know what you are doing.
1639 bool "Support for hot-pluggable CPUs"
1640 depends on SMP && HOTPLUG
1642 Say Y here to allow turning CPUs off and on. CPUs can be
1643 controlled through /sys/devices/system/cpu.
1644 ( Note: power management support will enable this option
1645 automatically on SMP systems. )
1646 Say N if you want to disable CPU hotplug.
1650 prompt "Compat VDSO support"
1651 depends on X86_32 || IA32_EMULATION
1653 Map the 32-bit VDSO to the predictable old-style address too.
1655 Say N here if you are running a sufficiently recent glibc
1656 version (2.3.3 or later), to remove the high-mapped
1657 VDSO mapping and to exclusively use the randomized VDSO.
1662 bool "Built-in kernel command line"
1664 Allow for specifying boot arguments to the kernel at
1665 build time. On some systems (e.g. embedded ones), it is
1666 necessary or convenient to provide some or all of the
1667 kernel boot arguments with the kernel itself (that is,
1668 to not rely on the boot loader to provide them.)
1670 To compile command line arguments into the kernel,
1671 set this option to 'Y', then fill in the
1672 the boot arguments in CONFIG_CMDLINE.
1674 Systems with fully functional boot loaders (i.e. non-embedded)
1675 should leave this option set to 'N'.
1678 string "Built-in kernel command string"
1679 depends on CMDLINE_BOOL
1682 Enter arguments here that should be compiled into the kernel
1683 image and used at boot time. If the boot loader provides a
1684 command line at boot time, it is appended to this string to
1685 form the full kernel command line, when the system boots.
1687 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1688 change this behavior.
1690 In most cases, the command line (whether built-in or provided
1691 by the boot loader) should specify the device for the root
1694 config CMDLINE_OVERRIDE
1695 bool "Built-in command line overrides boot loader arguments"
1696 depends on CMDLINE_BOOL
1698 Set this option to 'Y' to have the kernel ignore the boot loader
1699 command line, and use ONLY the built-in command line.
1701 This is used to work around broken boot loaders. This should
1702 be set to 'N' under normal conditions.
1706 config ARCH_ENABLE_MEMORY_HOTPLUG
1708 depends on X86_64 || (X86_32 && HIGHMEM)
1710 config ARCH_ENABLE_MEMORY_HOTREMOVE
1712 depends on MEMORY_HOTPLUG
1714 config USE_PERCPU_NUMA_NODE_ID
1718 menu "Power management and ACPI options"
1720 config ARCH_HIBERNATION_HEADER
1722 depends on X86_64 && HIBERNATION
1724 source "kernel/power/Kconfig"
1726 source "drivers/acpi/Kconfig"
1728 source "drivers/sfi/Kconfig"
1732 depends on APM || APM_MODULE
1735 tristate "APM (Advanced Power Management) BIOS support"
1736 depends on X86_32 && PM_SLEEP
1738 APM is a BIOS specification for saving power using several different
1739 techniques. This is mostly useful for battery powered laptops with
1740 APM compliant BIOSes. If you say Y here, the system time will be
1741 reset after a RESUME operation, the /proc/apm device will provide
1742 battery status information, and user-space programs will receive
1743 notification of APM "events" (e.g. battery status change).
1745 If you select "Y" here, you can disable actual use of the APM
1746 BIOS by passing the "apm=off" option to the kernel at boot time.
1748 Note that the APM support is almost completely disabled for
1749 machines with more than one CPU.
1751 In order to use APM, you will need supporting software. For location
1752 and more information, read <file:Documentation/power/pm.txt> and the
1753 Battery Powered Linux mini-HOWTO, available from
1754 <http://www.tldp.org/docs.html#howto>.
1756 This driver does not spin down disk drives (see the hdparm(8)
1757 manpage ("man 8 hdparm") for that), and it doesn't turn off
1758 VESA-compliant "green" monitors.
1760 This driver does not support the TI 4000M TravelMate and the ACER
1761 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1762 desktop machines also don't have compliant BIOSes, and this driver
1763 may cause those machines to panic during the boot phase.
1765 Generally, if you don't have a battery in your machine, there isn't
1766 much point in using this driver and you should say N. If you get
1767 random kernel OOPSes or reboots that don't seem to be related to
1768 anything, try disabling/enabling this option (or disabling/enabling
1771 Some other things you should try when experiencing seemingly random,
1774 1) make sure that you have enough swap space and that it is
1776 2) pass the "no-hlt" option to the kernel
1777 3) switch on floating point emulation in the kernel and pass
1778 the "no387" option to the kernel
1779 4) pass the "floppy=nodma" option to the kernel
1780 5) pass the "mem=4M" option to the kernel (thereby disabling
1781 all but the first 4 MB of RAM)
1782 6) make sure that the CPU is not over clocked.
1783 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1784 8) disable the cache from your BIOS settings
1785 9) install a fan for the video card or exchange video RAM
1786 10) install a better fan for the CPU
1787 11) exchange RAM chips
1788 12) exchange the motherboard.
1790 To compile this driver as a module, choose M here: the
1791 module will be called apm.
1795 config APM_IGNORE_USER_SUSPEND
1796 bool "Ignore USER SUSPEND"
1798 This option will ignore USER SUSPEND requests. On machines with a
1799 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1800 series notebooks, it is necessary to say Y because of a BIOS bug.
1802 config APM_DO_ENABLE
1803 bool "Enable PM at boot time"
1805 Enable APM features at boot time. From page 36 of the APM BIOS
1806 specification: "When disabled, the APM BIOS does not automatically
1807 power manage devices, enter the Standby State, enter the Suspend
1808 State, or take power saving steps in response to CPU Idle calls."
1809 This driver will make CPU Idle calls when Linux is idle (unless this
1810 feature is turned off -- see "Do CPU IDLE calls", below). This
1811 should always save battery power, but more complicated APM features
1812 will be dependent on your BIOS implementation. You may need to turn
1813 this option off if your computer hangs at boot time when using APM
1814 support, or if it beeps continuously instead of suspending. Turn
1815 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1816 T400CDT. This is off by default since most machines do fine without
1820 bool "Make CPU Idle calls when idle"
1822 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1823 On some machines, this can activate improved power savings, such as
1824 a slowed CPU clock rate, when the machine is idle. These idle calls
1825 are made after the idle loop has run for some length of time (e.g.,
1826 333 mS). On some machines, this will cause a hang at boot time or
1827 whenever the CPU becomes idle. (On machines with more than one CPU,
1828 this option does nothing.)
1830 config APM_DISPLAY_BLANK
1831 bool "Enable console blanking using APM"
1833 Enable console blanking using the APM. Some laptops can use this to
1834 turn off the LCD backlight when the screen blanker of the Linux
1835 virtual console blanks the screen. Note that this is only used by
1836 the virtual console screen blanker, and won't turn off the backlight
1837 when using the X Window system. This also doesn't have anything to
1838 do with your VESA-compliant power-saving monitor. Further, this
1839 option doesn't work for all laptops -- it might not turn off your
1840 backlight at all, or it might print a lot of errors to the console,
1841 especially if you are using gpm.
1843 config APM_ALLOW_INTS
1844 bool "Allow interrupts during APM BIOS calls"
1846 Normally we disable external interrupts while we are making calls to
1847 the APM BIOS as a measure to lessen the effects of a badly behaving
1848 BIOS implementation. The BIOS should reenable interrupts if it
1849 needs to. Unfortunately, some BIOSes do not -- especially those in
1850 many of the newer IBM Thinkpads. If you experience hangs when you
1851 suspend, try setting this to Y. Otherwise, say N.
1855 source "drivers/cpufreq/Kconfig"
1857 source "drivers/cpuidle/Kconfig"
1859 source "drivers/idle/Kconfig"
1864 menu "Bus options (PCI etc.)"
1869 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1871 Find out whether you have a PCI motherboard. PCI is the name of a
1872 bus system, i.e. the way the CPU talks to the other stuff inside
1873 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1874 VESA. If you have PCI, say Y, otherwise N.
1877 prompt "PCI access mode"
1878 depends on X86_32 && PCI
1881 On PCI systems, the BIOS can be used to detect the PCI devices and
1882 determine their configuration. However, some old PCI motherboards
1883 have BIOS bugs and may crash if this is done. Also, some embedded
1884 PCI-based systems don't have any BIOS at all. Linux can also try to
1885 detect the PCI hardware directly without using the BIOS.
1887 With this option, you can specify how Linux should detect the
1888 PCI devices. If you choose "BIOS", the BIOS will be used,
1889 if you choose "Direct", the BIOS won't be used, and if you
1890 choose "MMConfig", then PCI Express MMCONFIG will be used.
1891 If you choose "Any", the kernel will try MMCONFIG, then the
1892 direct access method and falls back to the BIOS if that doesn't
1893 work. If unsure, go with the default, which is "Any".
1898 config PCI_GOMMCONFIG
1915 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1917 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1920 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1924 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1928 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1932 depends on PCI && XEN
1940 bool "Support mmconfig PCI config space access"
1941 depends on X86_64 && PCI && ACPI
1943 config PCI_CNB20LE_QUIRK
1944 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1946 depends on PCI && EXPERIMENTAL
1948 Read the PCI windows out of the CNB20LE host bridge. This allows
1949 PCI hotplug to work on systems with the CNB20LE chipset which do
1952 There's no public spec for this chipset, and this functionality
1953 is known to be incomplete.
1955 You should say N unless you know you need this.
1958 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1959 depends on PCI_MSI && ACPI && EXPERIMENTAL
1961 DMA remapping (DMAR) devices support enables independent address
1962 translations for Direct Memory Access (DMA) from devices.
1963 These DMA remapping devices are reported via ACPI tables
1964 and include PCI device scope covered by these DMA
1967 config DMAR_DEFAULT_ON
1969 prompt "Enable DMA Remapping Devices by default"
1972 Selecting this option will enable a DMAR device at boot time if
1973 one is found. If this option is not selected, DMAR support can
1974 be enabled by passing intel_iommu=on to the kernel. It is
1975 recommended you say N here while the DMAR code remains
1978 config DMAR_BROKEN_GFX_WA
1979 bool "Workaround broken graphics drivers (going away soon)"
1980 depends on DMAR && BROKEN
1982 Current Graphics drivers tend to use physical address
1983 for DMA and avoid using DMA APIs. Setting this config
1984 option permits the IOMMU driver to set a unity map for
1985 all the OS-visible memory. Hence the driver can continue
1986 to use physical addresses for DMA, at least until this
1987 option is removed in the 2.6.32 kernel.
1989 config DMAR_FLOPPY_WA
1993 Floppy disk drivers are known to bypass DMA API calls
1994 thereby failing to work when IOMMU is enabled. This
1995 workaround will setup a 1:1 mapping for the first
1996 16MiB to make floppy (an ISA device) work.
1999 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
2000 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
2002 Supports Interrupt remapping for IO-APIC and MSI devices.
2003 To use x2apic mode in the CPU's which support x2APIC enhancements or
2004 to support platforms with CPU's having > 8 bit APIC ID, say Y.
2006 source "drivers/pci/pcie/Kconfig"
2008 source "drivers/pci/Kconfig"
2010 # x86_64 have no ISA slots, but can have ISA-style DMA.
2012 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2015 Enables ISA-style DMA support for devices requiring such controllers.
2023 Find out whether you have ISA slots on your motherboard. ISA is the
2024 name of a bus system, i.e. the way the CPU talks to the other stuff
2025 inside your box. Other bus systems are PCI, EISA, MicroChannel
2026 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2027 newer boards don't support it. If you have ISA, say Y, otherwise N.
2033 The Extended Industry Standard Architecture (EISA) bus was
2034 developed as an open alternative to the IBM MicroChannel bus.
2036 The EISA bus provided some of the features of the IBM MicroChannel
2037 bus while maintaining backward compatibility with cards made for
2038 the older ISA bus. The EISA bus saw limited use between 1988 and
2039 1995 when it was made obsolete by the PCI bus.
2041 Say Y here if you are building a kernel for an EISA-based machine.
2045 source "drivers/eisa/Kconfig"
2050 MicroChannel Architecture is found in some IBM PS/2 machines and
2051 laptops. It is a bus system similar to PCI or ISA. See
2052 <file:Documentation/mca.txt> (and especially the web page given
2053 there) before attempting to build an MCA bus kernel.
2055 source "drivers/mca/Kconfig"
2058 tristate "NatSemi SCx200 support"
2060 This provides basic support for National Semiconductor's
2061 (now AMD's) Geode processors. The driver probes for the
2062 PCI-IDs of several on-chip devices, so its a good dependency
2063 for other scx200_* drivers.
2065 If compiled as a module, the driver is named scx200.
2067 config SCx200HR_TIMER
2068 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2072 This driver provides a clocksource built upon the on-chip
2073 27MHz high-resolution timer. Its also a workaround for
2074 NSC Geode SC-1100's buggy TSC, which loses time when the
2075 processor goes idle (as is done by the scheduler). The
2076 other workaround is idle=poll boot option.
2079 bool "One Laptop Per Child support"
2085 Add support for detecting the unique features of the OLPC
2089 tristate "OLPC XO-1 support"
2090 depends on OLPC && MFD_CS5535
2092 Add support for non-essential features of the OLPC XO-1 laptop.
2098 depends on CPU_SUP_AMD && PCI
2100 source "drivers/pcmcia/Kconfig"
2102 source "drivers/pci/hotplug/Kconfig"
2105 bool "RapidIO support"
2109 If you say Y here, the kernel will include drivers and
2110 infrastructure code to support RapidIO interconnect devices.
2112 source "drivers/rapidio/Kconfig"
2117 menu "Executable file formats / Emulations"
2119 source "fs/Kconfig.binfmt"
2121 config IA32_EMULATION
2122 bool "IA32 Emulation"
2124 select COMPAT_BINFMT_ELF
2126 Include code to run 32-bit programs under a 64-bit kernel. You should
2127 likely turn this on, unless you're 100% sure that you don't have any
2128 32-bit programs left.
2131 tristate "IA32 a.out support"
2132 depends on IA32_EMULATION
2134 Support old a.out binaries in the 32bit emulation.
2138 depends on IA32_EMULATION
2140 config COMPAT_FOR_U64_ALIGNMENT
2144 config SYSVIPC_COMPAT
2146 depends on COMPAT && SYSVIPC
2150 depends on COMPAT && KEYS
2156 config HAVE_ATOMIC_IOMAP
2160 config HAVE_TEXT_POKE_SMP
2162 select STOP_MACHINE if SMP
2164 source "net/Kconfig"
2166 source "drivers/Kconfig"
2168 source "drivers/firmware/Kconfig"
2172 source "arch/x86/Kconfig.debug"
2174 source "security/Kconfig"
2176 source "crypto/Kconfig"
2178 source "arch/x86/kvm/Kconfig"
2180 source "lib/Kconfig"