2 mainmenu "Linux Kernel Configuration for x86"
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
21 select HAVE_AOUT if X86_32
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_PERF_EVENTS if (!M386 && !M486)
29 select HAVE_IOREMAP_PROT
32 select ARCH_WANT_OPTIONAL_GPIOLIB
33 select ARCH_WANT_FRAME_POINTERS
35 select HAVE_KRETPROBES
37 select HAVE_FTRACE_MCOUNT_RECORD
38 select HAVE_C_RECORDMCOUNT
39 select HAVE_DYNAMIC_FTRACE
40 select HAVE_FUNCTION_TRACER
41 select HAVE_FUNCTION_GRAPH_TRACER
42 select HAVE_FUNCTION_GRAPH_FP_TEST
43 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
44 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
45 select HAVE_SYSCALL_TRACEPOINTS
48 select HAVE_ARCH_TRACEHOOK
49 select HAVE_GENERIC_DMA_COHERENT if X86_32
50 select HAVE_EFFICIENT_UNALIGNED_ACCESS
51 select USER_STACKTRACE_SUPPORT
52 select HAVE_REGS_AND_STACK_ACCESS_API
53 select HAVE_DMA_API_DEBUG
54 select HAVE_KERNEL_GZIP
55 select HAVE_KERNEL_BZIP2
56 select HAVE_KERNEL_LZMA
57 select HAVE_KERNEL_LZO
58 select HAVE_HW_BREAKPOINT
59 select HAVE_MIXED_BREAKPOINTS_REGS
61 select HAVE_PERF_EVENTS_NMI
63 select HAVE_ARCH_KMEMCHECK
64 select HAVE_USER_RETURN_NOTIFIER
65 select HAVE_ARCH_JUMP_LABEL
66 select HAVE_TEXT_POKE_SMP
67 select HAVE_GENERIC_HARDIRQS
68 select HAVE_SPARSE_IRQ
69 select GENERIC_IRQ_PROBE
70 select GENERIC_PENDING_IRQ if SMP
72 config INSTRUCTION_DECODER
73 def_bool (KPROBES || PERF_EVENTS)
77 default "elf32-i386" if X86_32
78 default "elf64-x86-64" if X86_64
82 default "arch/x86/configs/i386_defconfig" if X86_32
83 default "arch/x86/configs/x86_64_defconfig" if X86_64
85 config GENERIC_CMOS_UPDATE
88 config CLOCKSOURCE_WATCHDOG
91 config GENERIC_CLOCKEVENTS
94 config GENERIC_CLOCKEVENTS_BROADCAST
96 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
98 config LOCKDEP_SUPPORT
101 config STACKTRACE_SUPPORT
104 config HAVE_LATENCYTOP_SUPPORT
116 config NEED_DMA_MAP_STATE
117 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
119 config NEED_SG_DMA_LENGTH
122 config GENERIC_ISA_DMA
131 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
133 config GENERIC_BUG_RELATIVE_POINTERS
136 config GENERIC_HWEIGHT
142 config ARCH_MAY_HAVE_PC_FDC
145 config RWSEM_GENERIC_SPINLOCK
148 config RWSEM_XCHGADD_ALGORITHM
151 config ARCH_HAS_CPU_IDLE_WAIT
154 config GENERIC_CALIBRATE_DELAY
157 config GENERIC_TIME_VSYSCALL
161 config ARCH_HAS_CPU_RELAX
164 config ARCH_HAS_DEFAULT_IDLE
167 config ARCH_HAS_CACHE_LINE_SIZE
170 config HAVE_SETUP_PER_CPU_AREA
173 config NEED_PER_CPU_EMBED_FIRST_CHUNK
176 config NEED_PER_CPU_PAGE_FIRST_CHUNK
179 config HAVE_CPUMASK_OF_CPU_MAP
182 config ARCH_HIBERNATION_POSSIBLE
185 config ARCH_SUSPEND_POSSIBLE
192 config ARCH_POPULATES_NODE_MAP
199 config ARCH_SUPPORTS_OPTIMIZED_INLINING
202 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
205 config HAVE_INTEL_TXT
207 depends on EXPERIMENTAL && DMAR && ACPI
209 config USE_GENERIC_SMP_HELPERS
215 depends on X86_32 && SMP
219 depends on X86_64 && SMP
225 config X86_TRAMPOLINE
227 depends on SMP || (64BIT && ACPI_SLEEP)
229 config X86_32_LAZY_GS
231 depends on X86_32 && !CC_STACKPROTECTOR
233 config ARCH_HWEIGHT_CFLAGS
235 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
236 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
241 config ARCH_CPU_PROBE_RELEASE
243 depends on HOTPLUG_CPU
245 source "init/Kconfig"
246 source "kernel/Kconfig.freezer"
248 menu "Processor type and features"
250 source "kernel/time/Kconfig"
253 bool "Symmetric multi-processing support"
255 This enables support for systems with more than one CPU. If you have
256 a system with only one CPU, like most personal computers, say N. If
257 you have a system with more than one CPU, say Y.
259 If you say N here, the kernel will run on single and multiprocessor
260 machines, but will use only one CPU of a multiprocessor machine. If
261 you say Y here, the kernel will run on many, but not all,
262 singleprocessor machines. On a singleprocessor machine, the kernel
263 will run faster if you say N here.
265 Note that if you say Y here and choose architecture "586" or
266 "Pentium" under "Processor family", the kernel will not work on 486
267 architectures. Similarly, multiprocessor kernels for the "PPro"
268 architecture may not work on all Pentium based boards.
270 People using multiprocessor machines who say Y here should also say
271 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
272 Management" code will be disabled if you say Y here.
274 See also <file:Documentation/i386/IO-APIC.txt>,
275 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
276 <http://www.tldp.org/docs.html#howto>.
278 If you don't know what to do here, say N.
281 bool "Support x2apic"
282 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
284 This enables x2apic support on CPUs that have this feature.
286 This allows 32-bit apic IDs (so it can support very large systems),
287 and accesses the local apic via MSRs not via mmio.
289 If you don't know what to do here, say N.
292 bool "Enable MPS table" if ACPI
294 depends on X86_LOCAL_APIC
296 For old smp systems that do not have proper acpi support. Newer systems
297 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
300 bool "Support for big SMP systems with more than 8 CPUs"
301 depends on X86_32 && SMP
303 This option is needed for the systems that have more than 8 CPUs
306 config X86_EXTENDED_PLATFORM
307 bool "Support for extended (non-PC) x86 platforms"
310 If you disable this option then the kernel will only support
311 standard PC platforms. (which covers the vast majority of
314 If you enable this option then you'll be able to select support
315 for the following (non-PC) 32 bit x86 platforms:
319 SGI 320/540 (Visual Workstation)
320 Summit/EXA (IBM x440)
321 Unisys ES7000 IA32 series
322 Moorestown MID devices
324 If you have one of these systems, or if you want to build a
325 generic distribution kernel, say Y here - otherwise say N.
329 config X86_EXTENDED_PLATFORM
330 bool "Support for extended (non-PC) x86 platforms"
333 If you disable this option then the kernel will only support
334 standard PC platforms. (which covers the vast majority of
337 If you enable this option then you'll be able to select support
338 for the following (non-PC) 64 bit x86 platforms:
342 If you have one of these systems, or if you want to build a
343 generic distribution kernel, say Y here - otherwise say N.
345 # This is an alphabetically sorted list of 64 bit extended platforms
346 # Please maintain the alphabetic order if and when there are additions
351 depends on X86_64 && PCI
352 depends on X86_EXTENDED_PLATFORM
354 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
355 supposed to run on these EM64T-based machines. Only choose this option
356 if you have one of these machines.
359 bool "SGI Ultraviolet"
361 depends on X86_EXTENDED_PLATFORM
363 depends on X86_X2APIC
365 This option is needed in order to support SGI Ultraviolet systems.
366 If you don't have one of these, you should say N here.
368 # Following is an alphabetically sorted list of 32 bit extended platforms
369 # Please maintain the alphabetic order if and when there are additions
374 depends on X86_EXTENDED_PLATFORM
376 Select this for an AMD Elan processor.
378 Do not use this option for K6/Athlon/Opteron processors!
380 If unsure, choose "PC-compatible" instead.
383 bool "Moorestown MID platform"
387 depends on X86_EXTENDED_PLATFORM
388 depends on X86_IO_APIC
391 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
392 Internet Device(MID) platform. Moorestown consists of two chips:
393 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
394 Unlike standard x86 PCs, Moorestown does not have many legacy devices
395 nor standard legacy replacement devices/features. e.g. Moorestown does
396 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
399 bool "RDC R-321x SoC"
401 depends on X86_EXTENDED_PLATFORM
403 select X86_REBOOTFIXUPS
405 This option is needed for RDC R-321x system-on-chip, also known
407 If you don't have one of these chips, you should say N here.
409 config X86_32_NON_STANDARD
410 bool "Support non-standard 32-bit SMP architectures"
411 depends on X86_32 && SMP
412 depends on X86_EXTENDED_PLATFORM
414 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
415 subarchitectures. It is intended for a generic binary kernel.
416 if you select them all, kernel will probe it one by one. and will
419 # Alphabetically sorted list of Non standard 32 bit platforms
422 bool "NUMAQ (IBM/Sequent)"
423 depends on X86_32_NON_STANDARD
428 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
429 NUMA multiquad box. This changes the way that processors are
430 bootstrapped, and uses Clustered Logical APIC addressing mode instead
431 of Flat Logical. You will need a new lynxer.elf file to flash your
432 firmware with - send email to <Martin.Bligh@us.ibm.com>.
434 config X86_SUPPORTS_MEMORY_FAILURE
436 # MCE code calls memory_failure():
438 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
439 depends on !X86_NUMAQ
440 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
441 depends on X86_64 || !SPARSEMEM
442 select ARCH_SUPPORTS_MEMORY_FAILURE
445 bool "SGI 320/540 (Visual Workstation)"
446 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
447 depends on X86_32_NON_STANDARD
449 The SGI Visual Workstation series is an IA32-based workstation
450 based on SGI systems chips with some legacy PC hardware attached.
452 Say Y here to create a kernel to run on the SGI 320 or 540.
454 A kernel compiled for the Visual Workstation will run on general
455 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
458 bool "Summit/EXA (IBM x440)"
459 depends on X86_32_NON_STANDARD
461 This option is needed for IBM systems that use the Summit/EXA chipset.
462 In particular, it is needed for the x440.
465 bool "Unisys ES7000 IA32 series"
466 depends on X86_32_NON_STANDARD && X86_BIGSMP
468 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
469 supposed to run on an IA32-based Unisys ES7000 system.
471 config SCHED_OMIT_FRAME_POINTER
473 prompt "Single-depth WCHAN output"
476 Calculate simpler /proc/<PID>/wchan values. If this option
477 is disabled then wchan values will recurse back to the
478 caller function. This provides more accurate wchan values,
479 at the expense of slightly more scheduling overhead.
481 If in doubt, say "Y".
483 menuconfig PARAVIRT_GUEST
484 bool "Paravirtualized guest support"
486 Say Y here to get to see options related to running Linux under
487 various hypervisors. This option alone does not add any kernel code.
489 If you say N, all options in this submenu will be skipped and disabled.
493 source "arch/x86/xen/Kconfig"
496 bool "KVM paravirtualized clock"
498 select PARAVIRT_CLOCK
500 Turning on this option will allow you to run a paravirtualized clock
501 when running over the KVM hypervisor. Instead of relying on a PIT
502 (or probably other) emulation by the underlying device model, the host
503 provides the guest with timing infrastructure such as time of day, and
507 bool "KVM Guest support"
510 This option enables various optimizations for running under the KVM
513 source "arch/x86/lguest/Kconfig"
516 bool "Enable paravirtualization code"
518 This changes the kernel so it can modify itself when it is run
519 under a hypervisor, potentially improving performance significantly
520 over full virtualization. However, when run without a hypervisor
521 the kernel is theoretically slower and slightly larger.
523 config PARAVIRT_SPINLOCKS
524 bool "Paravirtualization layer for spinlocks"
525 depends on PARAVIRT && SMP && EXPERIMENTAL
527 Paravirtualized spinlocks allow a pvops backend to replace the
528 spinlock implementation with something virtualization-friendly
529 (for example, block the virtual CPU rather than spinning).
531 Unfortunately the downside is an up to 5% performance hit on
532 native kernels, with various workloads.
534 If you are unsure how to answer this question, answer N.
536 config PARAVIRT_CLOCK
541 config PARAVIRT_DEBUG
542 bool "paravirt-ops debugging"
543 depends on PARAVIRT && DEBUG_KERNEL
545 Enable to debug paravirt_ops internals. Specifically, BUG if
546 a paravirt_op is missing when it is called.
554 This option adds a kernel parameter 'memtest', which allows memtest
556 memtest=0, mean disabled; -- default
557 memtest=1, mean do 1 test pattern;
559 memtest=4, mean do 4 test patterns.
560 If you are unsure how to answer this question, answer N.
562 config X86_SUMMIT_NUMA
564 depends on X86_32 && NUMA && X86_32_NON_STANDARD
566 config X86_CYCLONE_TIMER
568 depends on X86_32_NON_STANDARD
570 source "arch/x86/Kconfig.cpu"
574 prompt "HPET Timer Support" if X86_32
576 Use the IA-PC HPET (High Precision Event Timer) to manage
577 time in preference to the PIT and RTC, if a HPET is
579 HPET is the next generation timer replacing legacy 8254s.
580 The HPET provides a stable time base on SMP
581 systems, unlike the TSC, but it is more expensive to access,
582 as it is off-chip. You can find the HPET spec at
583 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
585 You can safely choose Y here. However, HPET will only be
586 activated if the platform and the BIOS support this feature.
587 Otherwise the 8254 will be used for timing services.
589 Choose N to continue using the legacy 8254 timer.
591 config HPET_EMULATE_RTC
593 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
597 prompt "Langwell APB Timer Support" if X86_MRST
599 APB timer is the replacement for 8254, HPET on X86 MID platforms.
600 The APBT provides a stable time base on SMP
601 systems, unlike the TSC, but it is more expensive to access,
602 as it is off-chip. APB timers are always running regardless of CPU
603 C states, they are used as per CPU clockevent device when possible.
605 # Mark as embedded because too many people got it wrong.
606 # The code disables itself when not needed.
609 bool "Enable DMI scanning" if EMBEDDED
611 Enabled scanning of DMI to identify machine quirks. Say Y
612 here unless you have verified that your setup is not
613 affected by entries in the DMI blacklist. Required by PNP
617 bool "GART IOMMU support" if EMBEDDED
620 depends on X86_64 && PCI && AMD_NB
622 Support for full DMA access of devices with 32bit memory access only
623 on systems with more than 3GB. This is usually needed for USB,
624 sound, many IDE/SATA chipsets and some other devices.
625 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
626 based hardware IOMMU and a software bounce buffer based IOMMU used
627 on Intel systems and as fallback.
628 The code is only active when needed (enough memory and limited
629 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
633 bool "IBM Calgary IOMMU support"
635 depends on X86_64 && PCI && EXPERIMENTAL
637 Support for hardware IOMMUs in IBM's xSeries x366 and x460
638 systems. Needed to run systems with more than 3GB of memory
639 properly with 32-bit PCI devices that do not support DAC
640 (Double Address Cycle). Calgary also supports bus level
641 isolation, where all DMAs pass through the IOMMU. This
642 prevents them from going anywhere except their intended
643 destination. This catches hard-to-find kernel bugs and
644 mis-behaving drivers and devices that do not use the DMA-API
645 properly to set up their DMA buffers. The IOMMU can be
646 turned off at boot time with the iommu=off parameter.
647 Normally the kernel will make the right choice by itself.
650 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
652 prompt "Should Calgary be enabled by default?"
653 depends on CALGARY_IOMMU
655 Should Calgary be enabled by default? if you choose 'y', Calgary
656 will be used (if it exists). If you choose 'n', Calgary will not be
657 used even if it exists. If you choose 'n' and would like to use
658 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
662 bool "AMD IOMMU support"
665 depends on X86_64 && PCI && ACPI
667 With this option you can enable support for AMD IOMMU hardware in
668 your system. An IOMMU is a hardware component which provides
669 remapping of DMA memory accesses from devices. With an AMD IOMMU you
670 can isolate the the DMA memory of different devices and protect the
671 system from misbehaving device drivers or hardware.
673 You can find out if your system has an AMD IOMMU if you look into
674 your BIOS for an option to enable it or if you have an IVRS ACPI
677 config AMD_IOMMU_STATS
678 bool "Export AMD IOMMU statistics to debugfs"
682 This option enables code in the AMD IOMMU driver to collect various
683 statistics about whats happening in the driver and exports that
684 information to userspace via debugfs.
687 # need this always selected by IOMMU for the VIA workaround
691 Support for software bounce buffers used on x86-64 systems
692 which don't have a hardware IOMMU (e.g. the current generation
693 of Intel's x86-64 CPUs). Using this PCI devices which can only
694 access 32-bits of memory can be used on systems with more than
695 3 GB of memory. If unsure, say Y.
698 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
701 def_bool (AMD_IOMMU || DMAR)
704 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
705 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
706 select CPUMASK_OFFSTACK
708 Enable maximum number of CPUS and NUMA Nodes for this architecture.
712 int "Maximum number of CPUs" if SMP && !MAXSMP
713 range 2 8 if SMP && X86_32 && !X86_BIGSMP
714 range 2 512 if SMP && !MAXSMP
716 default "4096" if MAXSMP
717 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
720 This allows you to specify the maximum number of CPUs which this
721 kernel will support. The maximum supported value is 512 and the
722 minimum value which makes sense is 2.
724 This is purely to save memory - each supported CPU adds
725 approximately eight kilobytes to the kernel image.
728 bool "SMT (Hyperthreading) scheduler support"
731 SMT scheduler support improves the CPU scheduler's decision making
732 when dealing with Intel Pentium 4 chips with HyperThreading at a
733 cost of slightly increased overhead in some places. If unsure say
738 prompt "Multi-core scheduler support"
741 Multi-core scheduler support improves the CPU scheduler's decision
742 making when dealing with multi-core CPU chips at a cost of slightly
743 increased overhead in some places. If unsure say N here.
745 config IRQ_TIME_ACCOUNTING
746 bool "Fine granularity task level IRQ time accounting"
749 Select this option to enable fine granularity task irq time
750 accounting. This is done by reading a timestamp on each
751 transitions between softirq and hardirq state, so there can be a
752 small performance impact.
754 If in doubt, say N here.
756 source "kernel/Kconfig.preempt"
759 bool "Local APIC support on uniprocessors"
760 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
762 A local APIC (Advanced Programmable Interrupt Controller) is an
763 integrated interrupt controller in the CPU. If you have a single-CPU
764 system which has a processor with a local APIC, you can say Y here to
765 enable and use it. If you say Y here even though your machine doesn't
766 have a local APIC, then the kernel will still run with no slowdown at
767 all. The local APIC supports CPU-generated self-interrupts (timer,
768 performance counters), and the NMI watchdog which detects hard
772 bool "IO-APIC support on uniprocessors"
773 depends on X86_UP_APIC
775 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
776 SMP-capable replacement for PC-style interrupt controllers. Most
777 SMP systems and many recent uniprocessor systems have one.
779 If you have a single-CPU system with an IO-APIC, you can say Y here
780 to use it. If you say Y here even though your machine doesn't have
781 an IO-APIC, then the kernel will still run with no slowdown at all.
783 config X86_LOCAL_APIC
785 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
789 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
791 config X86_VISWS_APIC
793 depends on X86_32 && X86_VISWS
795 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
796 bool "Reroute for broken boot IRQs"
797 depends on X86_IO_APIC
799 This option enables a workaround that fixes a source of
800 spurious interrupts. This is recommended when threaded
801 interrupt handling is used on systems where the generation of
802 superfluous "boot interrupts" cannot be disabled.
804 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
805 entry in the chipset's IO-APIC is masked (as, e.g. the RT
806 kernel does during interrupt handling). On chipsets where this
807 boot IRQ generation cannot be disabled, this workaround keeps
808 the original IRQ line masked so that only the equivalent "boot
809 IRQ" is delivered to the CPUs. The workaround also tells the
810 kernel to set up the IRQ handler on the boot IRQ line. In this
811 way only one interrupt is delivered to the kernel. Otherwise
812 the spurious second interrupt may cause the kernel to bring
813 down (vital) interrupt lines.
815 Only affects "broken" chipsets. Interrupt sharing may be
816 increased on these systems.
819 bool "Machine Check / overheating reporting"
821 Machine Check support allows the processor to notify the
822 kernel if it detects a problem (e.g. overheating, data corruption).
823 The action the kernel takes depends on the severity of the problem,
824 ranging from warning messages to halting the machine.
828 prompt "Intel MCE features"
829 depends on X86_MCE && X86_LOCAL_APIC
831 Additional support for intel specific MCE features such as
836 prompt "AMD MCE features"
837 depends on X86_MCE && X86_LOCAL_APIC
839 Additional support for AMD specific MCE features such as
840 the DRAM Error Threshold.
842 config X86_ANCIENT_MCE
843 bool "Support for old Pentium 5 / WinChip machine checks"
844 depends on X86_32 && X86_MCE
846 Include support for machine check handling on old Pentium 5 or WinChip
847 systems. These typically need to be enabled explicitely on the command
850 config X86_MCE_THRESHOLD
851 depends on X86_MCE_AMD || X86_MCE_INTEL
854 config X86_MCE_INJECT
856 tristate "Machine check injector support"
858 Provide support for injecting machine checks for testing purposes.
859 If you don't know what a machine check is and you don't do kernel
860 QA it is safe to say n.
862 config X86_THERMAL_VECTOR
864 depends on X86_MCE_INTEL
867 bool "Enable VM86 support" if EMBEDDED
871 This option is required by programs like DOSEMU to run 16-bit legacy
872 code on X86 processors. It also may be needed by software like
873 XFree86 to initialize some video cards via BIOS. Disabling this
874 option saves about 6k.
877 tristate "Toshiba Laptop support"
880 This adds a driver to safely access the System Management Mode of
881 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
882 not work on models with a Phoenix BIOS. The System Management Mode
883 is used to set the BIOS and power saving options on Toshiba portables.
885 For information on utilities to make use of this driver see the
886 Toshiba Linux utilities web site at:
887 <http://www.buzzard.org.uk/toshiba/>.
889 Say Y if you intend to run this kernel on a Toshiba portable.
893 tristate "Dell laptop support"
895 This adds a driver to safely access the System Management Mode
896 of the CPU on the Dell Inspiron 8000. The System Management Mode
897 is used to read cpu temperature and cooling fan status and to
898 control the fans on the I8K portables.
900 This driver has been tested only on the Inspiron 8000 but it may
901 also work with other Dell laptops. You can force loading on other
902 models by passing the parameter `force=1' to the module. Use at
905 For information on utilities to make use of this driver see the
906 I8K Linux utilities web site at:
907 <http://people.debian.org/~dz/i8k/>
909 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
912 config X86_REBOOTFIXUPS
913 bool "Enable X86 board specific fixups for reboot"
916 This enables chipset and/or board specific fixups to be done
917 in order to get reboot to work correctly. This is only needed on
918 some combinations of hardware and BIOS. The symptom, for which
919 this config is intended, is when reboot ends with a stalled/hung
922 Currently, the only fixup is for the Geode machines using
923 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
925 Say Y if you want to enable the fixup. Currently, it's safe to
926 enable this option even if you don't need it.
930 tristate "/dev/cpu/microcode - microcode support"
933 If you say Y here, you will be able to update the microcode on
934 certain Intel and AMD processors. The Intel support is for the
935 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
936 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
937 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
938 You will obviously need the actual microcode binary data itself
939 which is not shipped with the Linux kernel.
941 This option selects the general module only, you need to select
942 at least one vendor specific module as well.
944 To compile this driver as a module, choose M here: the
945 module will be called microcode.
947 config MICROCODE_INTEL
948 bool "Intel microcode patch loading support"
953 This options enables microcode patch loading support for Intel
956 For latest news and information on obtaining all the required
957 Intel ingredients for this driver, check:
958 <http://www.urbanmyth.org/microcode/>.
961 bool "AMD microcode patch loading support"
965 If you select this option, microcode patch loading support for AMD
966 processors will be enabled.
968 config MICROCODE_OLD_INTERFACE
973 tristate "/dev/cpu/*/msr - Model-specific register support"
975 This device gives privileged processes access to the x86
976 Model-Specific Registers (MSRs). It is a character device with
977 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
978 MSR accesses are directed to a specific CPU on multi-processor
982 tristate "/dev/cpu/*/cpuid - CPU information support"
984 This device gives processes access to the x86 CPUID instruction to
985 be executed on a specific processor. It is a character device
986 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
990 prompt "High Memory Support"
991 default HIGHMEM64G if X86_NUMAQ
997 depends on !X86_NUMAQ
999 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1000 However, the address space of 32-bit x86 processors is only 4
1001 Gigabytes large. That means that, if you have a large amount of
1002 physical memory, not all of it can be "permanently mapped" by the
1003 kernel. The physical memory that's not permanently mapped is called
1006 If you are compiling a kernel which will never run on a machine with
1007 more than 1 Gigabyte total physical RAM, answer "off" here (default
1008 choice and suitable for most users). This will result in a "3GB/1GB"
1009 split: 3GB are mapped so that each process sees a 3GB virtual memory
1010 space and the remaining part of the 4GB virtual memory space is used
1011 by the kernel to permanently map as much physical memory as
1014 If the machine has between 1 and 4 Gigabytes physical RAM, then
1017 If more than 4 Gigabytes is used then answer "64GB" here. This
1018 selection turns Intel PAE (Physical Address Extension) mode on.
1019 PAE implements 3-level paging on IA32 processors. PAE is fully
1020 supported by Linux, PAE mode is implemented on all recent Intel
1021 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1022 then the kernel will not boot on CPUs that don't support PAE!
1024 The actual amount of total physical memory will either be
1025 auto detected or can be forced by using a kernel command line option
1026 such as "mem=256M". (Try "man bootparam" or see the documentation of
1027 your boot loader (lilo or loadlin) about how to pass options to the
1028 kernel at boot time.)
1030 If unsure, say "off".
1034 depends on !X86_NUMAQ
1036 Select this if you have a 32-bit processor and between 1 and 4
1037 gigabytes of physical RAM.
1041 depends on !M386 && !M486
1044 Select this if you have a 32-bit processor and more than 4
1045 gigabytes of physical RAM.
1050 depends on EXPERIMENTAL
1051 prompt "Memory split" if EMBEDDED
1055 Select the desired split between kernel and user memory.
1057 If the address range available to the kernel is less than the
1058 physical memory installed, the remaining memory will be available
1059 as "high memory". Accessing high memory is a little more costly
1060 than low memory, as it needs to be mapped into the kernel first.
1061 Note that increasing the kernel address space limits the range
1062 available to user programs, making the address space there
1063 tighter. Selecting anything other than the default 3G/1G split
1064 will also likely make your kernel incompatible with binary-only
1067 If you are not absolutely sure what you are doing, leave this
1071 bool "3G/1G user/kernel split"
1072 config VMSPLIT_3G_OPT
1074 bool "3G/1G user/kernel split (for full 1G low memory)"
1076 bool "2G/2G user/kernel split"
1077 config VMSPLIT_2G_OPT
1079 bool "2G/2G user/kernel split (for full 2G low memory)"
1081 bool "1G/3G user/kernel split"
1086 default 0xB0000000 if VMSPLIT_3G_OPT
1087 default 0x80000000 if VMSPLIT_2G
1088 default 0x78000000 if VMSPLIT_2G_OPT
1089 default 0x40000000 if VMSPLIT_1G
1095 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1098 bool "PAE (Physical Address Extension) Support"
1099 depends on X86_32 && !HIGHMEM4G
1101 PAE is required for NX support, and furthermore enables
1102 larger swapspace support for non-overcommit purposes. It
1103 has the cost of more pagetable lookup overhead, and also
1104 consumes more pagetable space per process.
1106 config ARCH_PHYS_ADDR_T_64BIT
1107 def_bool X86_64 || X86_PAE
1109 config ARCH_DMA_ADDR_T_64BIT
1110 def_bool X86_64 || HIGHMEM64G
1112 config DIRECT_GBPAGES
1113 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1117 Allow the kernel linear mapping to use 1GB pages on CPUs that
1118 support it. This can improve the kernel's performance a tiny bit by
1119 reducing TLB pressure. If in doubt, say "Y".
1121 # Common NUMA Features
1123 bool "Numa Memory Allocation and Scheduler Support"
1125 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1126 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1128 Enable NUMA (Non Uniform Memory Access) support.
1130 The kernel will try to allocate memory used by a CPU on the
1131 local memory controller of the CPU and add some more
1132 NUMA awareness to the kernel.
1134 For 64-bit this is recommended if the system is Intel Core i7
1135 (or later), AMD Opteron, or EM64T NUMA.
1137 For 32-bit this is only needed on (rare) 32-bit-only platforms
1138 that support NUMA topologies, such as NUMAQ / Summit, or if you
1139 boot a 32-bit kernel on a 64-bit NUMA platform.
1141 Otherwise, you should say N.
1143 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1144 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1148 prompt "Old style AMD Opteron NUMA detection"
1149 depends on X86_64 && NUMA && PCI
1151 Enable K8 NUMA node topology detection. You should say Y here if
1152 you have a multi processor AMD K8 system. This uses an old
1153 method to read the NUMA configuration directly from the builtin
1154 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1155 instead, which also takes priority if both are compiled in.
1157 config X86_64_ACPI_NUMA
1159 prompt "ACPI NUMA detection"
1160 depends on X86_64 && NUMA && ACPI && PCI
1163 Enable ACPI SRAT based node topology detection.
1165 # Some NUMA nodes have memory ranges that span
1166 # other nodes. Even though a pfn is valid and
1167 # between a node's start and end pfns, it may not
1168 # reside on that node. See memmap_init_zone()
1170 config NODES_SPAN_OTHER_NODES
1172 depends on X86_64_ACPI_NUMA
1175 bool "NUMA emulation"
1176 depends on X86_64 && NUMA
1178 Enable NUMA emulation. A flat machine will be split
1179 into virtual nodes when booted with "numa=fake=N", where N is the
1180 number of nodes. This is only useful for debugging.
1183 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1185 default "10" if MAXSMP
1186 default "6" if X86_64
1187 default "4" if X86_NUMAQ
1189 depends on NEED_MULTIPLE_NODES
1191 Specify the maximum number of NUMA Nodes available on the target
1192 system. Increases memory reserved to accommodate various tables.
1194 config HAVE_ARCH_BOOTMEM
1196 depends on X86_32 && NUMA
1198 config ARCH_HAVE_MEMORY_PRESENT
1200 depends on X86_32 && DISCONTIGMEM
1202 config NEED_NODE_MEMMAP_SIZE
1204 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1206 config HAVE_ARCH_ALLOC_REMAP
1208 depends on X86_32 && NUMA
1210 config ARCH_FLATMEM_ENABLE
1212 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1214 config ARCH_DISCONTIGMEM_ENABLE
1216 depends on NUMA && X86_32
1218 config ARCH_DISCONTIGMEM_DEFAULT
1220 depends on NUMA && X86_32
1222 config ARCH_PROC_KCORE_TEXT
1224 depends on X86_64 && PROC_KCORE
1226 config ARCH_SPARSEMEM_DEFAULT
1230 config ARCH_SPARSEMEM_ENABLE
1232 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1233 select SPARSEMEM_STATIC if X86_32
1234 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1236 config ARCH_SELECT_MEMORY_MODEL
1238 depends on ARCH_SPARSEMEM_ENABLE
1240 config ARCH_MEMORY_PROBE
1242 depends on MEMORY_HOTPLUG
1244 config ILLEGAL_POINTER_VALUE
1247 default 0xdead000000000000 if X86_64
1252 bool "Allocate 3rd-level pagetables from highmem"
1255 The VM uses one page table entry for each page of physical memory.
1256 For systems with a lot of RAM, this can be wasteful of precious
1257 low memory. Setting this option will put user-space page table
1258 entries in high memory.
1260 config X86_CHECK_BIOS_CORRUPTION
1261 bool "Check for low memory corruption"
1263 Periodically check for memory corruption in low memory, which
1264 is suspected to be caused by BIOS. Even when enabled in the
1265 configuration, it is disabled at runtime. Enable it by
1266 setting "memory_corruption_check=1" on the kernel command
1267 line. By default it scans the low 64k of memory every 60
1268 seconds; see the memory_corruption_check_size and
1269 memory_corruption_check_period parameters in
1270 Documentation/kernel-parameters.txt to adjust this.
1272 When enabled with the default parameters, this option has
1273 almost no overhead, as it reserves a relatively small amount
1274 of memory and scans it infrequently. It both detects corruption
1275 and prevents it from affecting the running system.
1277 It is, however, intended as a diagnostic tool; if repeatable
1278 BIOS-originated corruption always affects the same memory,
1279 you can use memmap= to prevent the kernel from using that
1282 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1283 bool "Set the default setting of memory_corruption_check"
1284 depends on X86_CHECK_BIOS_CORRUPTION
1287 Set whether the default state of memory_corruption_check is
1290 config X86_RESERVE_LOW
1291 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1295 Specify the amount of low memory to reserve for the BIOS.
1297 The first page contains BIOS data structures that the kernel
1298 must not use, so that page must always be reserved.
1300 By default we reserve the first 64K of physical RAM, as a
1301 number of BIOSes are known to corrupt that memory range
1302 during events such as suspend/resume or monitor cable
1303 insertion, so it must not be used by the kernel.
1305 You can set this to 4 if you are absolutely sure that you
1306 trust the BIOS to get all its memory reservations and usages
1307 right. If you know your BIOS have problems beyond the
1308 default 64K area, you can set this to 640 to avoid using the
1309 entire low memory range.
1311 If you have doubts about the BIOS (e.g. suspend/resume does
1312 not work or there's kernel crashes after certain hardware
1313 hotplug events) then you might want to enable
1314 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1315 typical corruption patterns.
1317 Leave this to the default value of 64 if you are unsure.
1319 config MATH_EMULATION
1321 prompt "Math emulation" if X86_32
1323 Linux can emulate a math coprocessor (used for floating point
1324 operations) if you don't have one. 486DX and Pentium processors have
1325 a math coprocessor built in, 486SX and 386 do not, unless you added
1326 a 487DX or 387, respectively. (The messages during boot time can
1327 give you some hints here ["man dmesg"].) Everyone needs either a
1328 coprocessor or this emulation.
1330 If you don't have a math coprocessor, you need to say Y here; if you
1331 say Y here even though you have a coprocessor, the coprocessor will
1332 be used nevertheless. (This behavior can be changed with the kernel
1333 command line option "no387", which comes handy if your coprocessor
1334 is broken. Try "man bootparam" or see the documentation of your boot
1335 loader (lilo or loadlin) about how to pass options to the kernel at
1336 boot time.) This means that it is a good idea to say Y here if you
1337 intend to use this kernel on different machines.
1339 More information about the internals of the Linux math coprocessor
1340 emulation can be found in <file:arch/x86/math-emu/README>.
1342 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1343 kernel, it won't hurt.
1347 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1349 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1350 the Memory Type Range Registers (MTRRs) may be used to control
1351 processor access to memory ranges. This is most useful if you have
1352 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1353 allows bus write transfers to be combined into a larger transfer
1354 before bursting over the PCI/AGP bus. This can increase performance
1355 of image write operations 2.5 times or more. Saying Y here creates a
1356 /proc/mtrr file which may be used to manipulate your processor's
1357 MTRRs. Typically the X server should use this.
1359 This code has a reasonably generic interface so that similar
1360 control registers on other processors can be easily supported
1363 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1364 Registers (ARRs) which provide a similar functionality to MTRRs. For
1365 these, the ARRs are used to emulate the MTRRs.
1366 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1367 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1368 write-combining. All of these processors are supported by this code
1369 and it makes sense to say Y here if you have one of them.
1371 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1372 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1373 can lead to all sorts of problems, so it's good to say Y here.
1375 You can safely say Y even if your machine doesn't have MTRRs, you'll
1376 just add about 9 KB to your kernel.
1378 See <file:Documentation/x86/mtrr.txt> for more information.
1380 config MTRR_SANITIZER
1382 prompt "MTRR cleanup support"
1385 Convert MTRR layout from continuous to discrete, so X drivers can
1386 add writeback entries.
1388 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1389 The largest mtrr entry size for a continuous block can be set with
1394 config MTRR_SANITIZER_ENABLE_DEFAULT
1395 int "MTRR cleanup enable value (0-1)"
1398 depends on MTRR_SANITIZER
1400 Enable mtrr cleanup default value
1402 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1403 int "MTRR cleanup spare reg num (0-7)"
1406 depends on MTRR_SANITIZER
1408 mtrr cleanup spare entries default, it can be changed via
1409 mtrr_spare_reg_nr=N on the kernel command line.
1413 prompt "x86 PAT support" if EMBEDDED
1416 Use PAT attributes to setup page level cache control.
1418 PATs are the modern equivalents of MTRRs and are much more
1419 flexible than MTRRs.
1421 Say N here if you see bootup problems (boot crash, boot hang,
1422 spontaneous reboots) or a non-working video driver.
1426 config ARCH_USES_PG_UNCACHED
1431 bool "EFI runtime service support"
1434 This enables the kernel to use EFI runtime services that are
1435 available (such as the EFI variable services).
1437 This option is only useful on systems that have EFI firmware.
1438 In addition, you should use the latest ELILO loader available
1439 at <http://elilo.sourceforge.net> in order to take advantage
1440 of EFI runtime services. However, even with this option, the
1441 resultant kernel should continue to boot on existing non-EFI
1446 prompt "Enable seccomp to safely compute untrusted bytecode"
1448 This kernel feature is useful for number crunching applications
1449 that may need to compute untrusted bytecode during their
1450 execution. By using pipes or other transports made available to
1451 the process as file descriptors supporting the read/write
1452 syscalls, it's possible to isolate those applications in
1453 their own address space using seccomp. Once seccomp is
1454 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1455 and the task is only allowed to execute a few safe syscalls
1456 defined by each seccomp mode.
1458 If unsure, say Y. Only embedded should say N here.
1460 config CC_STACKPROTECTOR
1461 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1463 This option turns on the -fstack-protector GCC feature. This
1464 feature puts, at the beginning of functions, a canary value on
1465 the stack just before the return address, and validates
1466 the value just before actually returning. Stack based buffer
1467 overflows (that need to overwrite this return address) now also
1468 overwrite the canary, which gets detected and the attack is then
1469 neutralized via a kernel panic.
1471 This feature requires gcc version 4.2 or above, or a distribution
1472 gcc with the feature backported. Older versions are automatically
1473 detected and for those versions, this configuration option is
1474 ignored. (and a warning is printed during bootup)
1476 source kernel/Kconfig.hz
1479 bool "kexec system call"
1481 kexec is a system call that implements the ability to shutdown your
1482 current kernel, and to start another kernel. It is like a reboot
1483 but it is independent of the system firmware. And like a reboot
1484 you can start any kernel with it, not just Linux.
1486 The name comes from the similarity to the exec system call.
1488 It is an ongoing process to be certain the hardware in a machine
1489 is properly shutdown, so do not be surprised if this code does not
1490 initially work for you. It may help to enable device hotplugging
1491 support. As of this writing the exact hardware interface is
1492 strongly in flux, so no good recommendation can be made.
1495 bool "kernel crash dumps"
1496 depends on X86_64 || (X86_32 && HIGHMEM)
1498 Generate crash dump after being started by kexec.
1499 This should be normally only set in special crash dump kernels
1500 which are loaded in the main kernel with kexec-tools into
1501 a specially reserved region and then later executed after
1502 a crash by kdump/kexec. The crash dump kernel must be compiled
1503 to a memory address not used by the main kernel or BIOS using
1504 PHYSICAL_START, or it must be built as a relocatable image
1505 (CONFIG_RELOCATABLE=y).
1506 For more details see Documentation/kdump/kdump.txt
1509 bool "kexec jump (EXPERIMENTAL)"
1510 depends on EXPERIMENTAL
1511 depends on KEXEC && HIBERNATION
1513 Jump between original kernel and kexeced kernel and invoke
1514 code in physical address mode via KEXEC
1516 config PHYSICAL_START
1517 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1520 This gives the physical address where the kernel is loaded.
1522 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1523 bzImage will decompress itself to above physical address and
1524 run from there. Otherwise, bzImage will run from the address where
1525 it has been loaded by the boot loader and will ignore above physical
1528 In normal kdump cases one does not have to set/change this option
1529 as now bzImage can be compiled as a completely relocatable image
1530 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1531 address. This option is mainly useful for the folks who don't want
1532 to use a bzImage for capturing the crash dump and want to use a
1533 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1534 to be specifically compiled to run from a specific memory area
1535 (normally a reserved region) and this option comes handy.
1537 So if you are using bzImage for capturing the crash dump,
1538 leave the value here unchanged to 0x1000000 and set
1539 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1540 for capturing the crash dump change this value to start of
1541 the reserved region. In other words, it can be set based on
1542 the "X" value as specified in the "crashkernel=YM@XM"
1543 command line boot parameter passed to the panic-ed
1544 kernel. Please take a look at Documentation/kdump/kdump.txt
1545 for more details about crash dumps.
1547 Usage of bzImage for capturing the crash dump is recommended as
1548 one does not have to build two kernels. Same kernel can be used
1549 as production kernel and capture kernel. Above option should have
1550 gone away after relocatable bzImage support is introduced. But it
1551 is present because there are users out there who continue to use
1552 vmlinux for dump capture. This option should go away down the
1555 Don't change this unless you know what you are doing.
1558 bool "Build a relocatable kernel"
1561 This builds a kernel image that retains relocation information
1562 so it can be loaded someplace besides the default 1MB.
1563 The relocations tend to make the kernel binary about 10% larger,
1564 but are discarded at runtime.
1566 One use is for the kexec on panic case where the recovery kernel
1567 must live at a different physical address than the primary
1570 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1571 it has been loaded at and the compile time physical address
1572 (CONFIG_PHYSICAL_START) is ignored.
1574 # Relocation on x86-32 needs some additional build support
1575 config X86_NEED_RELOCS
1577 depends on X86_32 && RELOCATABLE
1579 config PHYSICAL_ALIGN
1580 hex "Alignment value to which kernel should be aligned" if X86_32
1582 range 0x2000 0x1000000
1584 This value puts the alignment restrictions on physical address
1585 where kernel is loaded and run from. Kernel is compiled for an
1586 address which meets above alignment restriction.
1588 If bootloader loads the kernel at a non-aligned address and
1589 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1590 address aligned to above value and run from there.
1592 If bootloader loads the kernel at a non-aligned address and
1593 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1594 load address and decompress itself to the address it has been
1595 compiled for and run from there. The address for which kernel is
1596 compiled already meets above alignment restrictions. Hence the
1597 end result is that kernel runs from a physical address meeting
1598 above alignment restrictions.
1600 Don't change this unless you know what you are doing.
1603 bool "Support for hot-pluggable CPUs"
1604 depends on SMP && HOTPLUG
1606 Say Y here to allow turning CPUs off and on. CPUs can be
1607 controlled through /sys/devices/system/cpu.
1608 ( Note: power management support will enable this option
1609 automatically on SMP systems. )
1610 Say N if you want to disable CPU hotplug.
1614 prompt "Compat VDSO support"
1615 depends on X86_32 || IA32_EMULATION
1617 Map the 32-bit VDSO to the predictable old-style address too.
1619 Say N here if you are running a sufficiently recent glibc
1620 version (2.3.3 or later), to remove the high-mapped
1621 VDSO mapping and to exclusively use the randomized VDSO.
1626 bool "Built-in kernel command line"
1628 Allow for specifying boot arguments to the kernel at
1629 build time. On some systems (e.g. embedded ones), it is
1630 necessary or convenient to provide some or all of the
1631 kernel boot arguments with the kernel itself (that is,
1632 to not rely on the boot loader to provide them.)
1634 To compile command line arguments into the kernel,
1635 set this option to 'Y', then fill in the
1636 the boot arguments in CONFIG_CMDLINE.
1638 Systems with fully functional boot loaders (i.e. non-embedded)
1639 should leave this option set to 'N'.
1642 string "Built-in kernel command string"
1643 depends on CMDLINE_BOOL
1646 Enter arguments here that should be compiled into the kernel
1647 image and used at boot time. If the boot loader provides a
1648 command line at boot time, it is appended to this string to
1649 form the full kernel command line, when the system boots.
1651 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1652 change this behavior.
1654 In most cases, the command line (whether built-in or provided
1655 by the boot loader) should specify the device for the root
1658 config CMDLINE_OVERRIDE
1659 bool "Built-in command line overrides boot loader arguments"
1660 depends on CMDLINE_BOOL
1662 Set this option to 'Y' to have the kernel ignore the boot loader
1663 command line, and use ONLY the built-in command line.
1665 This is used to work around broken boot loaders. This should
1666 be set to 'N' under normal conditions.
1670 config ARCH_ENABLE_MEMORY_HOTPLUG
1672 depends on X86_64 || (X86_32 && HIGHMEM)
1674 config ARCH_ENABLE_MEMORY_HOTREMOVE
1676 depends on MEMORY_HOTPLUG
1678 config HAVE_ARCH_EARLY_PFN_TO_NID
1682 config USE_PERCPU_NUMA_NODE_ID
1686 menu "Power management and ACPI options"
1688 config ARCH_HIBERNATION_HEADER
1690 depends on X86_64 && HIBERNATION
1692 source "kernel/power/Kconfig"
1694 source "drivers/acpi/Kconfig"
1696 source "drivers/sfi/Kconfig"
1700 depends on APM || APM_MODULE
1703 tristate "APM (Advanced Power Management) BIOS support"
1704 depends on X86_32 && PM_SLEEP
1706 APM is a BIOS specification for saving power using several different
1707 techniques. This is mostly useful for battery powered laptops with
1708 APM compliant BIOSes. If you say Y here, the system time will be
1709 reset after a RESUME operation, the /proc/apm device will provide
1710 battery status information, and user-space programs will receive
1711 notification of APM "events" (e.g. battery status change).
1713 If you select "Y" here, you can disable actual use of the APM
1714 BIOS by passing the "apm=off" option to the kernel at boot time.
1716 Note that the APM support is almost completely disabled for
1717 machines with more than one CPU.
1719 In order to use APM, you will need supporting software. For location
1720 and more information, read <file:Documentation/power/pm.txt> and the
1721 Battery Powered Linux mini-HOWTO, available from
1722 <http://www.tldp.org/docs.html#howto>.
1724 This driver does not spin down disk drives (see the hdparm(8)
1725 manpage ("man 8 hdparm") for that), and it doesn't turn off
1726 VESA-compliant "green" monitors.
1728 This driver does not support the TI 4000M TravelMate and the ACER
1729 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1730 desktop machines also don't have compliant BIOSes, and this driver
1731 may cause those machines to panic during the boot phase.
1733 Generally, if you don't have a battery in your machine, there isn't
1734 much point in using this driver and you should say N. If you get
1735 random kernel OOPSes or reboots that don't seem to be related to
1736 anything, try disabling/enabling this option (or disabling/enabling
1739 Some other things you should try when experiencing seemingly random,
1742 1) make sure that you have enough swap space and that it is
1744 2) pass the "no-hlt" option to the kernel
1745 3) switch on floating point emulation in the kernel and pass
1746 the "no387" option to the kernel
1747 4) pass the "floppy=nodma" option to the kernel
1748 5) pass the "mem=4M" option to the kernel (thereby disabling
1749 all but the first 4 MB of RAM)
1750 6) make sure that the CPU is not over clocked.
1751 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1752 8) disable the cache from your BIOS settings
1753 9) install a fan for the video card or exchange video RAM
1754 10) install a better fan for the CPU
1755 11) exchange RAM chips
1756 12) exchange the motherboard.
1758 To compile this driver as a module, choose M here: the
1759 module will be called apm.
1763 config APM_IGNORE_USER_SUSPEND
1764 bool "Ignore USER SUSPEND"
1766 This option will ignore USER SUSPEND requests. On machines with a
1767 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1768 series notebooks, it is necessary to say Y because of a BIOS bug.
1770 config APM_DO_ENABLE
1771 bool "Enable PM at boot time"
1773 Enable APM features at boot time. From page 36 of the APM BIOS
1774 specification: "When disabled, the APM BIOS does not automatically
1775 power manage devices, enter the Standby State, enter the Suspend
1776 State, or take power saving steps in response to CPU Idle calls."
1777 This driver will make CPU Idle calls when Linux is idle (unless this
1778 feature is turned off -- see "Do CPU IDLE calls", below). This
1779 should always save battery power, but more complicated APM features
1780 will be dependent on your BIOS implementation. You may need to turn
1781 this option off if your computer hangs at boot time when using APM
1782 support, or if it beeps continuously instead of suspending. Turn
1783 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1784 T400CDT. This is off by default since most machines do fine without
1788 bool "Make CPU Idle calls when idle"
1790 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1791 On some machines, this can activate improved power savings, such as
1792 a slowed CPU clock rate, when the machine is idle. These idle calls
1793 are made after the idle loop has run for some length of time (e.g.,
1794 333 mS). On some machines, this will cause a hang at boot time or
1795 whenever the CPU becomes idle. (On machines with more than one CPU,
1796 this option does nothing.)
1798 config APM_DISPLAY_BLANK
1799 bool "Enable console blanking using APM"
1801 Enable console blanking using the APM. Some laptops can use this to
1802 turn off the LCD backlight when the screen blanker of the Linux
1803 virtual console blanks the screen. Note that this is only used by
1804 the virtual console screen blanker, and won't turn off the backlight
1805 when using the X Window system. This also doesn't have anything to
1806 do with your VESA-compliant power-saving monitor. Further, this
1807 option doesn't work for all laptops -- it might not turn off your
1808 backlight at all, or it might print a lot of errors to the console,
1809 especially if you are using gpm.
1811 config APM_ALLOW_INTS
1812 bool "Allow interrupts during APM BIOS calls"
1814 Normally we disable external interrupts while we are making calls to
1815 the APM BIOS as a measure to lessen the effects of a badly behaving
1816 BIOS implementation. The BIOS should reenable interrupts if it
1817 needs to. Unfortunately, some BIOSes do not -- especially those in
1818 many of the newer IBM Thinkpads. If you experience hangs when you
1819 suspend, try setting this to Y. Otherwise, say N.
1823 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1825 source "drivers/cpuidle/Kconfig"
1827 source "drivers/idle/Kconfig"
1832 menu "Bus options (PCI etc.)"
1837 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1839 Find out whether you have a PCI motherboard. PCI is the name of a
1840 bus system, i.e. the way the CPU talks to the other stuff inside
1841 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1842 VESA. If you have PCI, say Y, otherwise N.
1845 prompt "PCI access mode"
1846 depends on X86_32 && PCI
1849 On PCI systems, the BIOS can be used to detect the PCI devices and
1850 determine their configuration. However, some old PCI motherboards
1851 have BIOS bugs and may crash if this is done. Also, some embedded
1852 PCI-based systems don't have any BIOS at all. Linux can also try to
1853 detect the PCI hardware directly without using the BIOS.
1855 With this option, you can specify how Linux should detect the
1856 PCI devices. If you choose "BIOS", the BIOS will be used,
1857 if you choose "Direct", the BIOS won't be used, and if you
1858 choose "MMConfig", then PCI Express MMCONFIG will be used.
1859 If you choose "Any", the kernel will try MMCONFIG, then the
1860 direct access method and falls back to the BIOS if that doesn't
1861 work. If unsure, go with the default, which is "Any".
1866 config PCI_GOMMCONFIG
1883 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1885 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1888 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1892 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1896 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1903 bool "Support mmconfig PCI config space access"
1904 depends on X86_64 && PCI && ACPI
1906 config PCI_CNB20LE_QUIRK
1907 bool "Read CNB20LE Host Bridge Windows"
1910 Read the PCI windows out of the CNB20LE host bridge. This allows
1911 PCI hotplug to work on systems with the CNB20LE chipset which do
1915 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1916 depends on PCI_MSI && ACPI && EXPERIMENTAL
1918 DMA remapping (DMAR) devices support enables independent address
1919 translations for Direct Memory Access (DMA) from devices.
1920 These DMA remapping devices are reported via ACPI tables
1921 and include PCI device scope covered by these DMA
1924 config DMAR_DEFAULT_ON
1926 prompt "Enable DMA Remapping Devices by default"
1929 Selecting this option will enable a DMAR device at boot time if
1930 one is found. If this option is not selected, DMAR support can
1931 be enabled by passing intel_iommu=on to the kernel. It is
1932 recommended you say N here while the DMAR code remains
1935 config DMAR_BROKEN_GFX_WA
1936 bool "Workaround broken graphics drivers (going away soon)"
1937 depends on DMAR && BROKEN
1939 Current Graphics drivers tend to use physical address
1940 for DMA and avoid using DMA APIs. Setting this config
1941 option permits the IOMMU driver to set a unity map for
1942 all the OS-visible memory. Hence the driver can continue
1943 to use physical addresses for DMA, at least until this
1944 option is removed in the 2.6.32 kernel.
1946 config DMAR_FLOPPY_WA
1950 Floppy disk drivers are known to bypass DMA API calls
1951 thereby failing to work when IOMMU is enabled. This
1952 workaround will setup a 1:1 mapping for the first
1953 16MiB to make floppy (an ISA device) work.
1956 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1957 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1959 Supports Interrupt remapping for IO-APIC and MSI devices.
1960 To use x2apic mode in the CPU's which support x2APIC enhancements or
1961 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1963 source "drivers/pci/pcie/Kconfig"
1965 source "drivers/pci/Kconfig"
1967 # x86_64 have no ISA slots, but do have ISA-style DMA.
1976 Find out whether you have ISA slots on your motherboard. ISA is the
1977 name of a bus system, i.e. the way the CPU talks to the other stuff
1978 inside your box. Other bus systems are PCI, EISA, MicroChannel
1979 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1980 newer boards don't support it. If you have ISA, say Y, otherwise N.
1986 The Extended Industry Standard Architecture (EISA) bus was
1987 developed as an open alternative to the IBM MicroChannel bus.
1989 The EISA bus provided some of the features of the IBM MicroChannel
1990 bus while maintaining backward compatibility with cards made for
1991 the older ISA bus. The EISA bus saw limited use between 1988 and
1992 1995 when it was made obsolete by the PCI bus.
1994 Say Y here if you are building a kernel for an EISA-based machine.
1998 source "drivers/eisa/Kconfig"
2003 MicroChannel Architecture is found in some IBM PS/2 machines and
2004 laptops. It is a bus system similar to PCI or ISA. See
2005 <file:Documentation/mca.txt> (and especially the web page given
2006 there) before attempting to build an MCA bus kernel.
2008 source "drivers/mca/Kconfig"
2011 tristate "NatSemi SCx200 support"
2013 This provides basic support for National Semiconductor's
2014 (now AMD's) Geode processors. The driver probes for the
2015 PCI-IDs of several on-chip devices, so its a good dependency
2016 for other scx200_* drivers.
2018 If compiled as a module, the driver is named scx200.
2020 config SCx200HR_TIMER
2021 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2025 This driver provides a clocksource built upon the on-chip
2026 27MHz high-resolution timer. Its also a workaround for
2027 NSC Geode SC-1100's buggy TSC, which loses time when the
2028 processor goes idle (as is done by the scheduler). The
2029 other workaround is idle=poll boot option.
2032 bool "One Laptop Per Child support"
2034 select OLPC_OPENFIRMWARE
2036 Add support for detecting the unique features of the OLPC
2040 tristate "OLPC XO-1 support"
2041 depends on OLPC && PCI
2043 Add support for non-essential features of the OLPC XO-1 laptop.
2045 config OLPC_OPENFIRMWARE
2046 bool "Support for OLPC's Open Firmware"
2047 depends on !X86_64 && !X86_PAE
2050 This option adds support for the implementation of Open Firmware
2051 that is used on the OLPC XO-1 Children's Machine.
2052 If unsure, say N here.
2058 depends on CPU_SUP_AMD && PCI
2060 source "drivers/pcmcia/Kconfig"
2062 source "drivers/pci/hotplug/Kconfig"
2067 menu "Executable file formats / Emulations"
2069 source "fs/Kconfig.binfmt"
2071 config IA32_EMULATION
2072 bool "IA32 Emulation"
2074 select COMPAT_BINFMT_ELF
2076 Include code to run 32-bit programs under a 64-bit kernel. You should
2077 likely turn this on, unless you're 100% sure that you don't have any
2078 32-bit programs left.
2081 tristate "IA32 a.out support"
2082 depends on IA32_EMULATION
2084 Support old a.out binaries in the 32bit emulation.
2088 depends on IA32_EMULATION
2090 config COMPAT_FOR_U64_ALIGNMENT
2094 config SYSVIPC_COMPAT
2096 depends on COMPAT && SYSVIPC
2101 config HAVE_ATOMIC_IOMAP
2105 config HAVE_TEXT_POKE_SMP
2107 select STOP_MACHINE if SMP
2109 source "net/Kconfig"
2111 source "drivers/Kconfig"
2113 source "drivers/firmware/Kconfig"
2117 source "arch/x86/Kconfig.debug"
2119 source "security/Kconfig"
2121 source "crypto/Kconfig"
2123 source "arch/x86/kvm/Kconfig"
2125 source "lib/Kconfig"
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