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
31 select ARCH_WANT_OPTIONAL_GPIOLIB
32 select ARCH_WANT_FRAME_POINTERS
34 select HAVE_KRETPROBES
36 select HAVE_FTRACE_MCOUNT_RECORD
37 select HAVE_C_RECORDMCOUNT
38 select HAVE_DYNAMIC_FTRACE
39 select HAVE_FUNCTION_TRACER
40 select HAVE_FUNCTION_GRAPH_TRACER
41 select HAVE_FUNCTION_GRAPH_FP_TEST
42 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
43 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
44 select HAVE_SYSCALL_TRACEPOINTS
47 select HAVE_ARCH_TRACEHOOK
48 select HAVE_GENERIC_DMA_COHERENT if X86_32
49 select HAVE_EFFICIENT_UNALIGNED_ACCESS
50 select USER_STACKTRACE_SUPPORT
51 select HAVE_REGS_AND_STACK_ACCESS_API
52 select HAVE_DMA_API_DEBUG
53 select HAVE_KERNEL_GZIP
54 select HAVE_KERNEL_BZIP2
55 select HAVE_KERNEL_LZMA
56 select HAVE_KERNEL_LZO
57 select HAVE_HW_BREAKPOINT
58 select HAVE_MIXED_BREAKPOINTS_REGS
60 select HAVE_PERF_EVENTS_NMI
62 select HAVE_ARCH_KMEMCHECK
63 select HAVE_USER_RETURN_NOTIFIER
64 select HAVE_ARCH_JUMP_LABEL
65 select HAVE_TEXT_POKE_SMP
66 select HAVE_GENERIC_HARDIRQS
67 select HAVE_SPARSE_IRQ
68 select GENERIC_IRQ_PROBE
69 select GENERIC_PENDING_IRQ if SMP
71 config INSTRUCTION_DECODER
72 def_bool (KPROBES || PERF_EVENTS)
76 default "elf32-i386" if X86_32
77 default "elf64-x86-64" if X86_64
81 default "arch/x86/configs/i386_defconfig" if X86_32
82 default "arch/x86/configs/x86_64_defconfig" if X86_64
84 config GENERIC_CMOS_UPDATE
87 config CLOCKSOURCE_WATCHDOG
90 config GENERIC_CLOCKEVENTS
93 config GENERIC_CLOCKEVENTS_BROADCAST
95 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
97 config LOCKDEP_SUPPORT
100 config STACKTRACE_SUPPORT
103 config HAVE_LATENCYTOP_SUPPORT
115 config NEED_DMA_MAP_STATE
116 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
118 config NEED_SG_DMA_LENGTH
121 config GENERIC_ISA_DMA
130 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
132 config GENERIC_BUG_RELATIVE_POINTERS
135 config GENERIC_HWEIGHT
141 config ARCH_MAY_HAVE_PC_FDC
144 config RWSEM_GENERIC_SPINLOCK
147 config RWSEM_XCHGADD_ALGORITHM
150 config ARCH_HAS_CPU_IDLE_WAIT
153 config GENERIC_CALIBRATE_DELAY
156 config GENERIC_TIME_VSYSCALL
160 config ARCH_HAS_CPU_RELAX
163 config ARCH_HAS_DEFAULT_IDLE
166 config ARCH_HAS_CACHE_LINE_SIZE
169 config HAVE_SETUP_PER_CPU_AREA
172 config NEED_PER_CPU_EMBED_FIRST_CHUNK
175 config NEED_PER_CPU_PAGE_FIRST_CHUNK
178 config HAVE_CPUMASK_OF_CPU_MAP
181 config ARCH_HIBERNATION_POSSIBLE
184 config ARCH_SUSPEND_POSSIBLE
191 config ARCH_POPULATES_NODE_MAP
198 config ARCH_SUPPORTS_OPTIMIZED_INLINING
201 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
204 config HAVE_EARLY_RES
207 config HAVE_INTEL_TXT
209 depends on EXPERIMENTAL && DMAR && ACPI
211 config USE_GENERIC_SMP_HELPERS
217 depends on X86_32 && SMP
221 depends on X86_64 && SMP
227 config X86_TRAMPOLINE
229 depends on SMP || (64BIT && ACPI_SLEEP)
231 config X86_32_LAZY_GS
233 depends on X86_32 && !CC_STACKPROTECTOR
235 config ARCH_HWEIGHT_CFLAGS
237 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
238 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
243 config ARCH_CPU_PROBE_RELEASE
245 depends on HOTPLUG_CPU
247 source "init/Kconfig"
248 source "kernel/Kconfig.freezer"
250 menu "Processor type and features"
252 source "kernel/time/Kconfig"
255 bool "Symmetric multi-processing support"
257 This enables support for systems with more than one CPU. If you have
258 a system with only one CPU, like most personal computers, say N. If
259 you have a system with more than one CPU, say Y.
261 If you say N here, the kernel will run on single and multiprocessor
262 machines, but will use only one CPU of a multiprocessor machine. If
263 you say Y here, the kernel will run on many, but not all,
264 singleprocessor machines. On a singleprocessor machine, the kernel
265 will run faster if you say N here.
267 Note that if you say Y here and choose architecture "586" or
268 "Pentium" under "Processor family", the kernel will not work on 486
269 architectures. Similarly, multiprocessor kernels for the "PPro"
270 architecture may not work on all Pentium based boards.
272 People using multiprocessor machines who say Y here should also say
273 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
274 Management" code will be disabled if you say Y here.
276 See also <file:Documentation/i386/IO-APIC.txt>,
277 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
278 <http://www.tldp.org/docs.html#howto>.
280 If you don't know what to do here, say N.
283 bool "Support x2apic"
284 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
286 This enables x2apic support on CPUs that have this feature.
288 This allows 32-bit apic IDs (so it can support very large systems),
289 and accesses the local apic via MSRs not via mmio.
291 If you don't know what to do here, say N.
294 bool "Enable MPS table" if ACPI
296 depends on X86_LOCAL_APIC
298 For old smp systems that do not have proper acpi support. Newer systems
299 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
302 bool "Support for big SMP systems with more than 8 CPUs"
303 depends on X86_32 && SMP
305 This option is needed for the systems that have more than 8 CPUs
308 config X86_EXTENDED_PLATFORM
309 bool "Support for extended (non-PC) x86 platforms"
312 If you disable this option then the kernel will only support
313 standard PC platforms. (which covers the vast majority of
316 If you enable this option then you'll be able to select support
317 for the following (non-PC) 32 bit x86 platforms:
321 SGI 320/540 (Visual Workstation)
322 Summit/EXA (IBM x440)
323 Unisys ES7000 IA32 series
324 Moorestown MID devices
326 If you have one of these systems, or if you want to build a
327 generic distribution kernel, say Y here - otherwise say N.
331 config X86_EXTENDED_PLATFORM
332 bool "Support for extended (non-PC) x86 platforms"
335 If you disable this option then the kernel will only support
336 standard PC platforms. (which covers the vast majority of
339 If you enable this option then you'll be able to select support
340 for the following (non-PC) 64 bit x86 platforms:
344 If you have one of these systems, or if you want to build a
345 generic distribution kernel, say Y here - otherwise say N.
347 # This is an alphabetically sorted list of 64 bit extended platforms
348 # Please maintain the alphabetic order if and when there are additions
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
376 depends on X86_EXTENDED_PLATFORM
378 Select this for an AMD Elan processor.
380 Do not use this option for K6/Athlon/Opteron processors!
382 If unsure, choose "PC-compatible" instead.
385 bool "Moorestown MID platform"
389 depends on X86_EXTENDED_PLATFORM
390 depends on X86_IO_APIC
393 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
394 Internet Device(MID) platform. Moorestown consists of two chips:
395 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
396 Unlike standard x86 PCs, Moorestown does not have many legacy devices
397 nor standard legacy replacement devices/features. e.g. Moorestown does
398 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
401 bool "RDC R-321x SoC"
403 depends on X86_EXTENDED_PLATFORM
405 select X86_REBOOTFIXUPS
407 This option is needed for RDC R-321x system-on-chip, also known
409 If you don't have one of these chips, you should say N here.
411 config X86_32_NON_STANDARD
412 bool "Support non-standard 32-bit SMP architectures"
413 depends on X86_32 && SMP
414 depends on X86_EXTENDED_PLATFORM
416 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
417 subarchitectures. It is intended for a generic binary kernel.
418 if you select them all, kernel will probe it one by one. and will
421 # Alphabetically sorted list of Non standard 32 bit platforms
424 bool "NUMAQ (IBM/Sequent)"
425 depends on X86_32_NON_STANDARD
430 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
431 NUMA multiquad box. This changes the way that processors are
432 bootstrapped, and uses Clustered Logical APIC addressing mode instead
433 of Flat Logical. You will need a new lynxer.elf file to flash your
434 firmware with - send email to <Martin.Bligh@us.ibm.com>.
436 config X86_SUPPORTS_MEMORY_FAILURE
438 # MCE code calls memory_failure():
440 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
441 depends on !X86_NUMAQ
442 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
443 depends on X86_64 || !SPARSEMEM
444 select ARCH_SUPPORTS_MEMORY_FAILURE
447 bool "SGI 320/540 (Visual Workstation)"
448 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
449 depends on X86_32_NON_STANDARD
451 The SGI Visual Workstation series is an IA32-based workstation
452 based on SGI systems chips with some legacy PC hardware attached.
454 Say Y here to create a kernel to run on the SGI 320 or 540.
456 A kernel compiled for the Visual Workstation will run on general
457 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
460 bool "Summit/EXA (IBM x440)"
461 depends on X86_32_NON_STANDARD
463 This option is needed for IBM systems that use the Summit/EXA chipset.
464 In particular, it is needed for the x440.
467 bool "Unisys ES7000 IA32 series"
468 depends on X86_32_NON_STANDARD && X86_BIGSMP
470 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
471 supposed to run on an IA32-based Unisys ES7000 system.
473 config SCHED_OMIT_FRAME_POINTER
475 prompt "Single-depth WCHAN output"
478 Calculate simpler /proc/<PID>/wchan values. If this option
479 is disabled then wchan values will recurse back to the
480 caller function. This provides more accurate wchan values,
481 at the expense of slightly more scheduling overhead.
483 If in doubt, say "Y".
485 menuconfig PARAVIRT_GUEST
486 bool "Paravirtualized guest support"
488 Say Y here to get to see options related to running Linux under
489 various hypervisors. This option alone does not add any kernel code.
491 If you say N, all options in this submenu will be skipped and disabled.
495 source "arch/x86/xen/Kconfig"
498 bool "KVM paravirtualized clock"
500 select PARAVIRT_CLOCK
502 Turning on this option will allow you to run a paravirtualized clock
503 when running over the KVM hypervisor. Instead of relying on a PIT
504 (or probably other) emulation by the underlying device model, the host
505 provides the guest with timing infrastructure such as time of day, and
509 bool "KVM Guest support"
512 This option enables various optimizations for running under the KVM
515 source "arch/x86/lguest/Kconfig"
518 bool "Enable paravirtualization code"
520 This changes the kernel so it can modify itself when it is run
521 under a hypervisor, potentially improving performance significantly
522 over full virtualization. However, when run without a hypervisor
523 the kernel is theoretically slower and slightly larger.
525 config PARAVIRT_SPINLOCKS
526 bool "Paravirtualization layer for spinlocks"
527 depends on PARAVIRT && SMP && EXPERIMENTAL
529 Paravirtualized spinlocks allow a pvops backend to replace the
530 spinlock implementation with something virtualization-friendly
531 (for example, block the virtual CPU rather than spinning).
533 Unfortunately the downside is an up to 5% performance hit on
534 native kernels, with various workloads.
536 If you are unsure how to answer this question, answer N.
538 config PARAVIRT_CLOCK
543 config PARAVIRT_DEBUG
544 bool "paravirt-ops debugging"
545 depends on PARAVIRT && DEBUG_KERNEL
547 Enable to debug paravirt_ops internals. Specifically, BUG if
548 a paravirt_op is missing when it is called.
552 bool "Disable Bootmem code"
554 Use early_res directly instead of bootmem before slab is ready.
555 - allocator (buddy) [generic]
556 - early allocator (bootmem) [generic]
557 - very early allocator (reserve_early*()) [x86]
558 - very very early allocator (early brk model) [x86]
559 So reduce one layer between early allocator to final allocator
565 This option adds a kernel parameter 'memtest', which allows memtest
567 memtest=0, mean disabled; -- default
568 memtest=1, mean do 1 test pattern;
570 memtest=4, mean do 4 test patterns.
571 If you are unsure how to answer this question, answer N.
573 config X86_SUMMIT_NUMA
575 depends on X86_32 && NUMA && X86_32_NON_STANDARD
577 config X86_CYCLONE_TIMER
579 depends on X86_32_NON_STANDARD
581 source "arch/x86/Kconfig.cpu"
585 prompt "HPET Timer Support" if X86_32
587 Use the IA-PC HPET (High Precision Event Timer) to manage
588 time in preference to the PIT and RTC, if a HPET is
590 HPET is the next generation timer replacing legacy 8254s.
591 The HPET provides a stable time base on SMP
592 systems, unlike the TSC, but it is more expensive to access,
593 as it is off-chip. You can find the HPET spec at
594 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
596 You can safely choose Y here. However, HPET will only be
597 activated if the platform and the BIOS support this feature.
598 Otherwise the 8254 will be used for timing services.
600 Choose N to continue using the legacy 8254 timer.
602 config HPET_EMULATE_RTC
604 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
608 prompt "Langwell APB Timer Support" if X86_MRST
610 APB timer is the replacement for 8254, HPET on X86 MID platforms.
611 The APBT provides a stable time base on SMP
612 systems, unlike the TSC, but it is more expensive to access,
613 as it is off-chip. APB timers are always running regardless of CPU
614 C states, they are used as per CPU clockevent device when possible.
616 # Mark as embedded because too many people got it wrong.
617 # The code disables itself when not needed.
620 bool "Enable DMI scanning" if EMBEDDED
622 Enabled scanning of DMI to identify machine quirks. Say Y
623 here unless you have verified that your setup is not
624 affected by entries in the DMI blacklist. Required by PNP
628 bool "GART IOMMU support" if EMBEDDED
631 depends on X86_64 && PCI && AMD_NB
633 Support for full DMA access of devices with 32bit memory access only
634 on systems with more than 3GB. This is usually needed for USB,
635 sound, many IDE/SATA chipsets and some other devices.
636 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
637 based hardware IOMMU and a software bounce buffer based IOMMU used
638 on Intel systems and as fallback.
639 The code is only active when needed (enough memory and limited
640 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
644 bool "IBM Calgary IOMMU support"
646 depends on X86_64 && PCI && EXPERIMENTAL
648 Support for hardware IOMMUs in IBM's xSeries x366 and x460
649 systems. Needed to run systems with more than 3GB of memory
650 properly with 32-bit PCI devices that do not support DAC
651 (Double Address Cycle). Calgary also supports bus level
652 isolation, where all DMAs pass through the IOMMU. This
653 prevents them from going anywhere except their intended
654 destination. This catches hard-to-find kernel bugs and
655 mis-behaving drivers and devices that do not use the DMA-API
656 properly to set up their DMA buffers. The IOMMU can be
657 turned off at boot time with the iommu=off parameter.
658 Normally the kernel will make the right choice by itself.
661 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
663 prompt "Should Calgary be enabled by default?"
664 depends on CALGARY_IOMMU
666 Should Calgary be enabled by default? if you choose 'y', Calgary
667 will be used (if it exists). If you choose 'n', Calgary will not be
668 used even if it exists. If you choose 'n' and would like to use
669 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
673 bool "AMD IOMMU support"
676 depends on X86_64 && PCI && ACPI
678 With this option you can enable support for AMD IOMMU hardware in
679 your system. An IOMMU is a hardware component which provides
680 remapping of DMA memory accesses from devices. With an AMD IOMMU you
681 can isolate the the DMA memory of different devices and protect the
682 system from misbehaving device drivers or hardware.
684 You can find out if your system has an AMD IOMMU if you look into
685 your BIOS for an option to enable it or if you have an IVRS ACPI
688 config AMD_IOMMU_STATS
689 bool "Export AMD IOMMU statistics to debugfs"
693 This option enables code in the AMD IOMMU driver to collect various
694 statistics about whats happening in the driver and exports that
695 information to userspace via debugfs.
698 # need this always selected by IOMMU for the VIA workaround
702 Support for software bounce buffers used on x86-64 systems
703 which don't have a hardware IOMMU (e.g. the current generation
704 of Intel's x86-64 CPUs). Using this PCI devices which can only
705 access 32-bits of memory can be used on systems with more than
706 3 GB of memory. If unsure, say Y.
709 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
712 def_bool (AMD_IOMMU || DMAR)
715 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
716 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
717 select CPUMASK_OFFSTACK
719 Enable maximum number of CPUS and NUMA Nodes for this architecture.
723 int "Maximum number of CPUs" if SMP && !MAXSMP
724 range 2 8 if SMP && X86_32 && !X86_BIGSMP
725 range 2 512 if SMP && !MAXSMP
727 default "4096" if MAXSMP
728 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
731 This allows you to specify the maximum number of CPUs which this
732 kernel will support. The maximum supported value is 512 and the
733 minimum value which makes sense is 2.
735 This is purely to save memory - each supported CPU adds
736 approximately eight kilobytes to the kernel image.
739 bool "SMT (Hyperthreading) scheduler support"
742 SMT scheduler support improves the CPU scheduler's decision making
743 when dealing with Intel Pentium 4 chips with HyperThreading at a
744 cost of slightly increased overhead in some places. If unsure say
749 prompt "Multi-core scheduler support"
752 Multi-core scheduler support improves the CPU scheduler's decision
753 making when dealing with multi-core CPU chips at a cost of slightly
754 increased overhead in some places. If unsure say N here.
756 config IRQ_TIME_ACCOUNTING
757 bool "Fine granularity task level IRQ time accounting"
760 Select this option to enable fine granularity task irq time
761 accounting. This is done by reading a timestamp on each
762 transitions between softirq and hardirq state, so there can be a
763 small performance impact.
765 If in doubt, say N here.
767 source "kernel/Kconfig.preempt"
770 bool "Local APIC support on uniprocessors"
771 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
773 A local APIC (Advanced Programmable Interrupt Controller) is an
774 integrated interrupt controller in the CPU. If you have a single-CPU
775 system which has a processor with a local APIC, you can say Y here to
776 enable and use it. If you say Y here even though your machine doesn't
777 have a local APIC, then the kernel will still run with no slowdown at
778 all. The local APIC supports CPU-generated self-interrupts (timer,
779 performance counters), and the NMI watchdog which detects hard
783 bool "IO-APIC support on uniprocessors"
784 depends on X86_UP_APIC
786 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
787 SMP-capable replacement for PC-style interrupt controllers. Most
788 SMP systems and many recent uniprocessor systems have one.
790 If you have a single-CPU system with an IO-APIC, you can say Y here
791 to use it. If you say Y here even though your machine doesn't have
792 an IO-APIC, then the kernel will still run with no slowdown at all.
794 config X86_LOCAL_APIC
796 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
800 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
802 config X86_VISWS_APIC
804 depends on X86_32 && X86_VISWS
806 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
807 bool "Reroute for broken boot IRQs"
808 depends on X86_IO_APIC
810 This option enables a workaround that fixes a source of
811 spurious interrupts. This is recommended when threaded
812 interrupt handling is used on systems where the generation of
813 superfluous "boot interrupts" cannot be disabled.
815 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
816 entry in the chipset's IO-APIC is masked (as, e.g. the RT
817 kernel does during interrupt handling). On chipsets where this
818 boot IRQ generation cannot be disabled, this workaround keeps
819 the original IRQ line masked so that only the equivalent "boot
820 IRQ" is delivered to the CPUs. The workaround also tells the
821 kernel to set up the IRQ handler on the boot IRQ line. In this
822 way only one interrupt is delivered to the kernel. Otherwise
823 the spurious second interrupt may cause the kernel to bring
824 down (vital) interrupt lines.
826 Only affects "broken" chipsets. Interrupt sharing may be
827 increased on these systems.
830 bool "Machine Check / overheating reporting"
832 Machine Check support allows the processor to notify the
833 kernel if it detects a problem (e.g. overheating, data corruption).
834 The action the kernel takes depends on the severity of the problem,
835 ranging from warning messages to halting the machine.
839 prompt "Intel MCE features"
840 depends on X86_MCE && X86_LOCAL_APIC
842 Additional support for intel specific MCE features such as
847 prompt "AMD MCE features"
848 depends on X86_MCE && X86_LOCAL_APIC
850 Additional support for AMD specific MCE features such as
851 the DRAM Error Threshold.
853 config X86_ANCIENT_MCE
854 bool "Support for old Pentium 5 / WinChip machine checks"
855 depends on X86_32 && X86_MCE
857 Include support for machine check handling on old Pentium 5 or WinChip
858 systems. These typically need to be enabled explicitely on the command
861 config X86_MCE_THRESHOLD
862 depends on X86_MCE_AMD || X86_MCE_INTEL
865 config X86_MCE_INJECT
867 tristate "Machine check injector support"
869 Provide support for injecting machine checks for testing purposes.
870 If you don't know what a machine check is and you don't do kernel
871 QA it is safe to say n.
873 config X86_THERMAL_VECTOR
875 depends on X86_MCE_INTEL
878 bool "Enable VM86 support" if EMBEDDED
882 This option is required by programs like DOSEMU to run 16-bit legacy
883 code on X86 processors. It also may be needed by software like
884 XFree86 to initialize some video cards via BIOS. Disabling this
885 option saves about 6k.
888 tristate "Toshiba Laptop support"
891 This adds a driver to safely access the System Management Mode of
892 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
893 not work on models with a Phoenix BIOS. The System Management Mode
894 is used to set the BIOS and power saving options on Toshiba portables.
896 For information on utilities to make use of this driver see the
897 Toshiba Linux utilities web site at:
898 <http://www.buzzard.org.uk/toshiba/>.
900 Say Y if you intend to run this kernel on a Toshiba portable.
904 tristate "Dell laptop support"
906 This adds a driver to safely access the System Management Mode
907 of the CPU on the Dell Inspiron 8000. The System Management Mode
908 is used to read cpu temperature and cooling fan status and to
909 control the fans on the I8K portables.
911 This driver has been tested only on the Inspiron 8000 but it may
912 also work with other Dell laptops. You can force loading on other
913 models by passing the parameter `force=1' to the module. Use at
916 For information on utilities to make use of this driver see the
917 I8K Linux utilities web site at:
918 <http://people.debian.org/~dz/i8k/>
920 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
923 config X86_REBOOTFIXUPS
924 bool "Enable X86 board specific fixups for reboot"
927 This enables chipset and/or board specific fixups to be done
928 in order to get reboot to work correctly. This is only needed on
929 some combinations of hardware and BIOS. The symptom, for which
930 this config is intended, is when reboot ends with a stalled/hung
933 Currently, the only fixup is for the Geode machines using
934 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
936 Say Y if you want to enable the fixup. Currently, it's safe to
937 enable this option even if you don't need it.
941 tristate "/dev/cpu/microcode - microcode support"
944 If you say Y here, you will be able to update the microcode on
945 certain Intel and AMD processors. The Intel support is for the
946 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
947 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
948 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
949 You will obviously need the actual microcode binary data itself
950 which is not shipped with the Linux kernel.
952 This option selects the general module only, you need to select
953 at least one vendor specific module as well.
955 To compile this driver as a module, choose M here: the
956 module will be called microcode.
958 config MICROCODE_INTEL
959 bool "Intel microcode patch loading support"
964 This options enables microcode patch loading support for Intel
967 For latest news and information on obtaining all the required
968 Intel ingredients for this driver, check:
969 <http://www.urbanmyth.org/microcode/>.
972 bool "AMD microcode patch loading support"
976 If you select this option, microcode patch loading support for AMD
977 processors will be enabled.
979 config MICROCODE_OLD_INTERFACE
984 tristate "/dev/cpu/*/msr - Model-specific register support"
986 This device gives privileged processes access to the x86
987 Model-Specific Registers (MSRs). It is a character device with
988 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
989 MSR accesses are directed to a specific CPU on multi-processor
993 tristate "/dev/cpu/*/cpuid - CPU information support"
995 This device gives processes access to the x86 CPUID instruction to
996 be executed on a specific processor. It is a character device
997 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1001 prompt "High Memory Support"
1002 default HIGHMEM64G if X86_NUMAQ
1008 depends on !X86_NUMAQ
1010 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1011 However, the address space of 32-bit x86 processors is only 4
1012 Gigabytes large. That means that, if you have a large amount of
1013 physical memory, not all of it can be "permanently mapped" by the
1014 kernel. The physical memory that's not permanently mapped is called
1017 If you are compiling a kernel which will never run on a machine with
1018 more than 1 Gigabyte total physical RAM, answer "off" here (default
1019 choice and suitable for most users). This will result in a "3GB/1GB"
1020 split: 3GB are mapped so that each process sees a 3GB virtual memory
1021 space and the remaining part of the 4GB virtual memory space is used
1022 by the kernel to permanently map as much physical memory as
1025 If the machine has between 1 and 4 Gigabytes physical RAM, then
1028 If more than 4 Gigabytes is used then answer "64GB" here. This
1029 selection turns Intel PAE (Physical Address Extension) mode on.
1030 PAE implements 3-level paging on IA32 processors. PAE is fully
1031 supported by Linux, PAE mode is implemented on all recent Intel
1032 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1033 then the kernel will not boot on CPUs that don't support PAE!
1035 The actual amount of total physical memory will either be
1036 auto detected or can be forced by using a kernel command line option
1037 such as "mem=256M". (Try "man bootparam" or see the documentation of
1038 your boot loader (lilo or loadlin) about how to pass options to the
1039 kernel at boot time.)
1041 If unsure, say "off".
1045 depends on !X86_NUMAQ
1047 Select this if you have a 32-bit processor and between 1 and 4
1048 gigabytes of physical RAM.
1052 depends on !M386 && !M486
1055 Select this if you have a 32-bit processor and more than 4
1056 gigabytes of physical RAM.
1061 depends on EXPERIMENTAL
1062 prompt "Memory split" if EMBEDDED
1066 Select the desired split between kernel and user memory.
1068 If the address range available to the kernel is less than the
1069 physical memory installed, the remaining memory will be available
1070 as "high memory". Accessing high memory is a little more costly
1071 than low memory, as it needs to be mapped into the kernel first.
1072 Note that increasing the kernel address space limits the range
1073 available to user programs, making the address space there
1074 tighter. Selecting anything other than the default 3G/1G split
1075 will also likely make your kernel incompatible with binary-only
1078 If you are not absolutely sure what you are doing, leave this
1082 bool "3G/1G user/kernel split"
1083 config VMSPLIT_3G_OPT
1085 bool "3G/1G user/kernel split (for full 1G low memory)"
1087 bool "2G/2G user/kernel split"
1088 config VMSPLIT_2G_OPT
1090 bool "2G/2G user/kernel split (for full 2G low memory)"
1092 bool "1G/3G user/kernel split"
1097 default 0xB0000000 if VMSPLIT_3G_OPT
1098 default 0x80000000 if VMSPLIT_2G
1099 default 0x78000000 if VMSPLIT_2G_OPT
1100 default 0x40000000 if VMSPLIT_1G
1106 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1109 bool "PAE (Physical Address Extension) Support"
1110 depends on X86_32 && !HIGHMEM4G
1112 PAE is required for NX support, and furthermore enables
1113 larger swapspace support for non-overcommit purposes. It
1114 has the cost of more pagetable lookup overhead, and also
1115 consumes more pagetable space per process.
1117 config ARCH_PHYS_ADDR_T_64BIT
1118 def_bool X86_64 || X86_PAE
1120 config ARCH_DMA_ADDR_T_64BIT
1121 def_bool X86_64 || HIGHMEM64G
1123 config DIRECT_GBPAGES
1124 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1128 Allow the kernel linear mapping to use 1GB pages on CPUs that
1129 support it. This can improve the kernel's performance a tiny bit by
1130 reducing TLB pressure. If in doubt, say "Y".
1132 # Common NUMA Features
1134 bool "Numa Memory Allocation and Scheduler Support"
1136 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1137 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1139 Enable NUMA (Non Uniform Memory Access) support.
1141 The kernel will try to allocate memory used by a CPU on the
1142 local memory controller of the CPU and add some more
1143 NUMA awareness to the kernel.
1145 For 64-bit this is recommended if the system is Intel Core i7
1146 (or later), AMD Opteron, or EM64T NUMA.
1148 For 32-bit this is only needed on (rare) 32-bit-only platforms
1149 that support NUMA topologies, such as NUMAQ / Summit, or if you
1150 boot a 32-bit kernel on a 64-bit NUMA platform.
1152 Otherwise, you should say N.
1154 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1155 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1159 prompt "Old style AMD Opteron NUMA detection"
1160 depends on X86_64 && NUMA && PCI
1162 Enable K8 NUMA node topology detection. You should say Y here if
1163 you have a multi processor AMD K8 system. This uses an old
1164 method to read the NUMA configuration directly from the builtin
1165 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1166 instead, which also takes priority if both are compiled in.
1168 config X86_64_ACPI_NUMA
1170 prompt "ACPI NUMA detection"
1171 depends on X86_64 && NUMA && ACPI && PCI
1174 Enable ACPI SRAT based node topology detection.
1176 # Some NUMA nodes have memory ranges that span
1177 # other nodes. Even though a pfn is valid and
1178 # between a node's start and end pfns, it may not
1179 # reside on that node. See memmap_init_zone()
1181 config NODES_SPAN_OTHER_NODES
1183 depends on X86_64_ACPI_NUMA
1186 bool "NUMA emulation"
1187 depends on X86_64 && NUMA
1189 Enable NUMA emulation. A flat machine will be split
1190 into virtual nodes when booted with "numa=fake=N", where N is the
1191 number of nodes. This is only useful for debugging.
1194 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1196 default "10" if MAXSMP
1197 default "6" if X86_64
1198 default "4" if X86_NUMAQ
1200 depends on NEED_MULTIPLE_NODES
1202 Specify the maximum number of NUMA Nodes available on the target
1203 system. Increases memory reserved to accommodate various tables.
1205 config HAVE_ARCH_BOOTMEM
1207 depends on X86_32 && NUMA
1209 config ARCH_HAVE_MEMORY_PRESENT
1211 depends on X86_32 && DISCONTIGMEM
1213 config NEED_NODE_MEMMAP_SIZE
1215 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1217 config HAVE_ARCH_ALLOC_REMAP
1219 depends on X86_32 && NUMA
1221 config ARCH_FLATMEM_ENABLE
1223 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1225 config ARCH_DISCONTIGMEM_ENABLE
1227 depends on NUMA && X86_32
1229 config ARCH_DISCONTIGMEM_DEFAULT
1231 depends on NUMA && X86_32
1233 config ARCH_PROC_KCORE_TEXT
1235 depends on X86_64 && PROC_KCORE
1237 config ARCH_SPARSEMEM_DEFAULT
1241 config ARCH_SPARSEMEM_ENABLE
1243 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1244 select SPARSEMEM_STATIC if X86_32
1245 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1247 config ARCH_SELECT_MEMORY_MODEL
1249 depends on ARCH_SPARSEMEM_ENABLE
1251 config ARCH_MEMORY_PROBE
1253 depends on MEMORY_HOTPLUG
1255 config ILLEGAL_POINTER_VALUE
1258 default 0xdead000000000000 if X86_64
1263 bool "Allocate 3rd-level pagetables from highmem"
1266 The VM uses one page table entry for each page of physical memory.
1267 For systems with a lot of RAM, this can be wasteful of precious
1268 low memory. Setting this option will put user-space page table
1269 entries in high memory.
1271 config X86_CHECK_BIOS_CORRUPTION
1272 bool "Check for low memory corruption"
1274 Periodically check for memory corruption in low memory, which
1275 is suspected to be caused by BIOS. Even when enabled in the
1276 configuration, it is disabled at runtime. Enable it by
1277 setting "memory_corruption_check=1" on the kernel command
1278 line. By default it scans the low 64k of memory every 60
1279 seconds; see the memory_corruption_check_size and
1280 memory_corruption_check_period parameters in
1281 Documentation/kernel-parameters.txt to adjust this.
1283 When enabled with the default parameters, this option has
1284 almost no overhead, as it reserves a relatively small amount
1285 of memory and scans it infrequently. It both detects corruption
1286 and prevents it from affecting the running system.
1288 It is, however, intended as a diagnostic tool; if repeatable
1289 BIOS-originated corruption always affects the same memory,
1290 you can use memmap= to prevent the kernel from using that
1293 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1294 bool "Set the default setting of memory_corruption_check"
1295 depends on X86_CHECK_BIOS_CORRUPTION
1298 Set whether the default state of memory_corruption_check is
1301 config X86_RESERVE_LOW
1302 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1306 Specify the amount of low memory to reserve for the BIOS.
1308 The first page contains BIOS data structures that the kernel
1309 must not use, so that page must always be reserved.
1311 By default we reserve the first 64K of physical RAM, as a
1312 number of BIOSes are known to corrupt that memory range
1313 during events such as suspend/resume or monitor cable
1314 insertion, so it must not be used by the kernel.
1316 You can set this to 4 if you are absolutely sure that you
1317 trust the BIOS to get all its memory reservations and usages
1318 right. If you know your BIOS have problems beyond the
1319 default 64K area, you can set this to 640 to avoid using the
1320 entire low memory range.
1322 If you have doubts about the BIOS (e.g. suspend/resume does
1323 not work or there's kernel crashes after certain hardware
1324 hotplug events) then you might want to enable
1325 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1326 typical corruption patterns.
1328 Leave this to the default value of 64 if you are unsure.
1330 config MATH_EMULATION
1332 prompt "Math emulation" if X86_32
1334 Linux can emulate a math coprocessor (used for floating point
1335 operations) if you don't have one. 486DX and Pentium processors have
1336 a math coprocessor built in, 486SX and 386 do not, unless you added
1337 a 487DX or 387, respectively. (The messages during boot time can
1338 give you some hints here ["man dmesg"].) Everyone needs either a
1339 coprocessor or this emulation.
1341 If you don't have a math coprocessor, you need to say Y here; if you
1342 say Y here even though you have a coprocessor, the coprocessor will
1343 be used nevertheless. (This behavior can be changed with the kernel
1344 command line option "no387", which comes handy if your coprocessor
1345 is broken. Try "man bootparam" or see the documentation of your boot
1346 loader (lilo or loadlin) about how to pass options to the kernel at
1347 boot time.) This means that it is a good idea to say Y here if you
1348 intend to use this kernel on different machines.
1350 More information about the internals of the Linux math coprocessor
1351 emulation can be found in <file:arch/x86/math-emu/README>.
1353 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1354 kernel, it won't hurt.
1358 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1360 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1361 the Memory Type Range Registers (MTRRs) may be used to control
1362 processor access to memory ranges. This is most useful if you have
1363 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1364 allows bus write transfers to be combined into a larger transfer
1365 before bursting over the PCI/AGP bus. This can increase performance
1366 of image write operations 2.5 times or more. Saying Y here creates a
1367 /proc/mtrr file which may be used to manipulate your processor's
1368 MTRRs. Typically the X server should use this.
1370 This code has a reasonably generic interface so that similar
1371 control registers on other processors can be easily supported
1374 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1375 Registers (ARRs) which provide a similar functionality to MTRRs. For
1376 these, the ARRs are used to emulate the MTRRs.
1377 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1378 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1379 write-combining. All of these processors are supported by this code
1380 and it makes sense to say Y here if you have one of them.
1382 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1383 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1384 can lead to all sorts of problems, so it's good to say Y here.
1386 You can safely say Y even if your machine doesn't have MTRRs, you'll
1387 just add about 9 KB to your kernel.
1389 See <file:Documentation/x86/mtrr.txt> for more information.
1391 config MTRR_SANITIZER
1393 prompt "MTRR cleanup support"
1396 Convert MTRR layout from continuous to discrete, so X drivers can
1397 add writeback entries.
1399 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1400 The largest mtrr entry size for a continuous block can be set with
1405 config MTRR_SANITIZER_ENABLE_DEFAULT
1406 int "MTRR cleanup enable value (0-1)"
1409 depends on MTRR_SANITIZER
1411 Enable mtrr cleanup default value
1413 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1414 int "MTRR cleanup spare reg num (0-7)"
1417 depends on MTRR_SANITIZER
1419 mtrr cleanup spare entries default, it can be changed via
1420 mtrr_spare_reg_nr=N on the kernel command line.
1424 prompt "x86 PAT support" if EMBEDDED
1427 Use PAT attributes to setup page level cache control.
1429 PATs are the modern equivalents of MTRRs and are much more
1430 flexible than MTRRs.
1432 Say N here if you see bootup problems (boot crash, boot hang,
1433 spontaneous reboots) or a non-working video driver.
1437 config ARCH_USES_PG_UNCACHED
1442 bool "EFI runtime service support"
1445 This enables the kernel to use EFI runtime services that are
1446 available (such as the EFI variable services).
1448 This option is only useful on systems that have EFI firmware.
1449 In addition, you should use the latest ELILO loader available
1450 at <http://elilo.sourceforge.net> in order to take advantage
1451 of EFI runtime services. However, even with this option, the
1452 resultant kernel should continue to boot on existing non-EFI
1457 prompt "Enable seccomp to safely compute untrusted bytecode"
1459 This kernel feature is useful for number crunching applications
1460 that may need to compute untrusted bytecode during their
1461 execution. By using pipes or other transports made available to
1462 the process as file descriptors supporting the read/write
1463 syscalls, it's possible to isolate those applications in
1464 their own address space using seccomp. Once seccomp is
1465 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1466 and the task is only allowed to execute a few safe syscalls
1467 defined by each seccomp mode.
1469 If unsure, say Y. Only embedded should say N here.
1471 config CC_STACKPROTECTOR
1472 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1474 This option turns on the -fstack-protector GCC feature. This
1475 feature puts, at the beginning of functions, a canary value on
1476 the stack just before the return address, and validates
1477 the value just before actually returning. Stack based buffer
1478 overflows (that need to overwrite this return address) now also
1479 overwrite the canary, which gets detected and the attack is then
1480 neutralized via a kernel panic.
1482 This feature requires gcc version 4.2 or above, or a distribution
1483 gcc with the feature backported. Older versions are automatically
1484 detected and for those versions, this configuration option is
1485 ignored. (and a warning is printed during bootup)
1487 source kernel/Kconfig.hz
1490 bool "kexec system call"
1492 kexec is a system call that implements the ability to shutdown your
1493 current kernel, and to start another kernel. It is like a reboot
1494 but it is independent of the system firmware. And like a reboot
1495 you can start any kernel with it, not just Linux.
1497 The name comes from the similarity to the exec system call.
1499 It is an ongoing process to be certain the hardware in a machine
1500 is properly shutdown, so do not be surprised if this code does not
1501 initially work for you. It may help to enable device hotplugging
1502 support. As of this writing the exact hardware interface is
1503 strongly in flux, so no good recommendation can be made.
1506 bool "kernel crash dumps"
1507 depends on X86_64 || (X86_32 && HIGHMEM)
1509 Generate crash dump after being started by kexec.
1510 This should be normally only set in special crash dump kernels
1511 which are loaded in the main kernel with kexec-tools into
1512 a specially reserved region and then later executed after
1513 a crash by kdump/kexec. The crash dump kernel must be compiled
1514 to a memory address not used by the main kernel or BIOS using
1515 PHYSICAL_START, or it must be built as a relocatable image
1516 (CONFIG_RELOCATABLE=y).
1517 For more details see Documentation/kdump/kdump.txt
1520 bool "kexec jump (EXPERIMENTAL)"
1521 depends on EXPERIMENTAL
1522 depends on KEXEC && HIBERNATION
1524 Jump between original kernel and kexeced kernel and invoke
1525 code in physical address mode via KEXEC
1527 config PHYSICAL_START
1528 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1531 This gives the physical address where the kernel is loaded.
1533 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1534 bzImage will decompress itself to above physical address and
1535 run from there. Otherwise, bzImage will run from the address where
1536 it has been loaded by the boot loader and will ignore above physical
1539 In normal kdump cases one does not have to set/change this option
1540 as now bzImage can be compiled as a completely relocatable image
1541 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1542 address. This option is mainly useful for the folks who don't want
1543 to use a bzImage for capturing the crash dump and want to use a
1544 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1545 to be specifically compiled to run from a specific memory area
1546 (normally a reserved region) and this option comes handy.
1548 So if you are using bzImage for capturing the crash dump,
1549 leave the value here unchanged to 0x1000000 and set
1550 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1551 for capturing the crash dump change this value to start of
1552 the reserved region. In other words, it can be set based on
1553 the "X" value as specified in the "crashkernel=YM@XM"
1554 command line boot parameter passed to the panic-ed
1555 kernel. Please take a look at Documentation/kdump/kdump.txt
1556 for more details about crash dumps.
1558 Usage of bzImage for capturing the crash dump is recommended as
1559 one does not have to build two kernels. Same kernel can be used
1560 as production kernel and capture kernel. Above option should have
1561 gone away after relocatable bzImage support is introduced. But it
1562 is present because there are users out there who continue to use
1563 vmlinux for dump capture. This option should go away down the
1566 Don't change this unless you know what you are doing.
1569 bool "Build a relocatable kernel"
1572 This builds a kernel image that retains relocation information
1573 so it can be loaded someplace besides the default 1MB.
1574 The relocations tend to make the kernel binary about 10% larger,
1575 but are discarded at runtime.
1577 One use is for the kexec on panic case where the recovery kernel
1578 must live at a different physical address than the primary
1581 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1582 it has been loaded at and the compile time physical address
1583 (CONFIG_PHYSICAL_START) is ignored.
1585 # Relocation on x86-32 needs some additional build support
1586 config X86_NEED_RELOCS
1588 depends on X86_32 && RELOCATABLE
1590 config PHYSICAL_ALIGN
1591 hex "Alignment value to which kernel should be aligned" if X86_32
1593 range 0x2000 0x1000000
1595 This value puts the alignment restrictions on physical address
1596 where kernel is loaded and run from. Kernel is compiled for an
1597 address which meets above alignment restriction.
1599 If bootloader loads the kernel at a non-aligned address and
1600 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1601 address aligned to above value and run from there.
1603 If bootloader loads the kernel at a non-aligned address and
1604 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1605 load address and decompress itself to the address it has been
1606 compiled for and run from there. The address for which kernel is
1607 compiled already meets above alignment restrictions. Hence the
1608 end result is that kernel runs from a physical address meeting
1609 above alignment restrictions.
1611 Don't change this unless you know what you are doing.
1614 bool "Support for hot-pluggable CPUs"
1615 depends on SMP && HOTPLUG
1617 Say Y here to allow turning CPUs off and on. CPUs can be
1618 controlled through /sys/devices/system/cpu.
1619 ( Note: power management support will enable this option
1620 automatically on SMP systems. )
1621 Say N if you want to disable CPU hotplug.
1625 prompt "Compat VDSO support"
1626 depends on X86_32 || IA32_EMULATION
1628 Map the 32-bit VDSO to the predictable old-style address too.
1630 Say N here if you are running a sufficiently recent glibc
1631 version (2.3.3 or later), to remove the high-mapped
1632 VDSO mapping and to exclusively use the randomized VDSO.
1637 bool "Built-in kernel command line"
1639 Allow for specifying boot arguments to the kernel at
1640 build time. On some systems (e.g. embedded ones), it is
1641 necessary or convenient to provide some or all of the
1642 kernel boot arguments with the kernel itself (that is,
1643 to not rely on the boot loader to provide them.)
1645 To compile command line arguments into the kernel,
1646 set this option to 'Y', then fill in the
1647 the boot arguments in CONFIG_CMDLINE.
1649 Systems with fully functional boot loaders (i.e. non-embedded)
1650 should leave this option set to 'N'.
1653 string "Built-in kernel command string"
1654 depends on CMDLINE_BOOL
1657 Enter arguments here that should be compiled into the kernel
1658 image and used at boot time. If the boot loader provides a
1659 command line at boot time, it is appended to this string to
1660 form the full kernel command line, when the system boots.
1662 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1663 change this behavior.
1665 In most cases, the command line (whether built-in or provided
1666 by the boot loader) should specify the device for the root
1669 config CMDLINE_OVERRIDE
1670 bool "Built-in command line overrides boot loader arguments"
1671 depends on CMDLINE_BOOL
1673 Set this option to 'Y' to have the kernel ignore the boot loader
1674 command line, and use ONLY the built-in command line.
1676 This is used to work around broken boot loaders. This should
1677 be set to 'N' under normal conditions.
1681 config ARCH_ENABLE_MEMORY_HOTPLUG
1683 depends on X86_64 || (X86_32 && HIGHMEM)
1685 config ARCH_ENABLE_MEMORY_HOTREMOVE
1687 depends on MEMORY_HOTPLUG
1689 config HAVE_ARCH_EARLY_PFN_TO_NID
1693 config USE_PERCPU_NUMA_NODE_ID
1697 menu "Power management and ACPI options"
1699 config ARCH_HIBERNATION_HEADER
1701 depends on X86_64 && HIBERNATION
1703 source "kernel/power/Kconfig"
1705 source "drivers/acpi/Kconfig"
1707 source "drivers/sfi/Kconfig"
1711 depends on APM || APM_MODULE
1714 tristate "APM (Advanced Power Management) BIOS support"
1715 depends on X86_32 && PM_SLEEP
1717 APM is a BIOS specification for saving power using several different
1718 techniques. This is mostly useful for battery powered laptops with
1719 APM compliant BIOSes. If you say Y here, the system time will be
1720 reset after a RESUME operation, the /proc/apm device will provide
1721 battery status information, and user-space programs will receive
1722 notification of APM "events" (e.g. battery status change).
1724 If you select "Y" here, you can disable actual use of the APM
1725 BIOS by passing the "apm=off" option to the kernel at boot time.
1727 Note that the APM support is almost completely disabled for
1728 machines with more than one CPU.
1730 In order to use APM, you will need supporting software. For location
1731 and more information, read <file:Documentation/power/pm.txt> and the
1732 Battery Powered Linux mini-HOWTO, available from
1733 <http://www.tldp.org/docs.html#howto>.
1735 This driver does not spin down disk drives (see the hdparm(8)
1736 manpage ("man 8 hdparm") for that), and it doesn't turn off
1737 VESA-compliant "green" monitors.
1739 This driver does not support the TI 4000M TravelMate and the ACER
1740 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1741 desktop machines also don't have compliant BIOSes, and this driver
1742 may cause those machines to panic during the boot phase.
1744 Generally, if you don't have a battery in your machine, there isn't
1745 much point in using this driver and you should say N. If you get
1746 random kernel OOPSes or reboots that don't seem to be related to
1747 anything, try disabling/enabling this option (or disabling/enabling
1750 Some other things you should try when experiencing seemingly random,
1753 1) make sure that you have enough swap space and that it is
1755 2) pass the "no-hlt" option to the kernel
1756 3) switch on floating point emulation in the kernel and pass
1757 the "no387" option to the kernel
1758 4) pass the "floppy=nodma" option to the kernel
1759 5) pass the "mem=4M" option to the kernel (thereby disabling
1760 all but the first 4 MB of RAM)
1761 6) make sure that the CPU is not over clocked.
1762 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1763 8) disable the cache from your BIOS settings
1764 9) install a fan for the video card or exchange video RAM
1765 10) install a better fan for the CPU
1766 11) exchange RAM chips
1767 12) exchange the motherboard.
1769 To compile this driver as a module, choose M here: the
1770 module will be called apm.
1774 config APM_IGNORE_USER_SUSPEND
1775 bool "Ignore USER SUSPEND"
1777 This option will ignore USER SUSPEND requests. On machines with a
1778 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1779 series notebooks, it is necessary to say Y because of a BIOS bug.
1781 config APM_DO_ENABLE
1782 bool "Enable PM at boot time"
1784 Enable APM features at boot time. From page 36 of the APM BIOS
1785 specification: "When disabled, the APM BIOS does not automatically
1786 power manage devices, enter the Standby State, enter the Suspend
1787 State, or take power saving steps in response to CPU Idle calls."
1788 This driver will make CPU Idle calls when Linux is idle (unless this
1789 feature is turned off -- see "Do CPU IDLE calls", below). This
1790 should always save battery power, but more complicated APM features
1791 will be dependent on your BIOS implementation. You may need to turn
1792 this option off if your computer hangs at boot time when using APM
1793 support, or if it beeps continuously instead of suspending. Turn
1794 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1795 T400CDT. This is off by default since most machines do fine without
1799 bool "Make CPU Idle calls when idle"
1801 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1802 On some machines, this can activate improved power savings, such as
1803 a slowed CPU clock rate, when the machine is idle. These idle calls
1804 are made after the idle loop has run for some length of time (e.g.,
1805 333 mS). On some machines, this will cause a hang at boot time or
1806 whenever the CPU becomes idle. (On machines with more than one CPU,
1807 this option does nothing.)
1809 config APM_DISPLAY_BLANK
1810 bool "Enable console blanking using APM"
1812 Enable console blanking using the APM. Some laptops can use this to
1813 turn off the LCD backlight when the screen blanker of the Linux
1814 virtual console blanks the screen. Note that this is only used by
1815 the virtual console screen blanker, and won't turn off the backlight
1816 when using the X Window system. This also doesn't have anything to
1817 do with your VESA-compliant power-saving monitor. Further, this
1818 option doesn't work for all laptops -- it might not turn off your
1819 backlight at all, or it might print a lot of errors to the console,
1820 especially if you are using gpm.
1822 config APM_ALLOW_INTS
1823 bool "Allow interrupts during APM BIOS calls"
1825 Normally we disable external interrupts while we are making calls to
1826 the APM BIOS as a measure to lessen the effects of a badly behaving
1827 BIOS implementation. The BIOS should reenable interrupts if it
1828 needs to. Unfortunately, some BIOSes do not -- especially those in
1829 many of the newer IBM Thinkpads. If you experience hangs when you
1830 suspend, try setting this to Y. Otherwise, say N.
1834 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1836 source "drivers/cpuidle/Kconfig"
1838 source "drivers/idle/Kconfig"
1843 menu "Bus options (PCI etc.)"
1848 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1850 Find out whether you have a PCI motherboard. PCI is the name of a
1851 bus system, i.e. the way the CPU talks to the other stuff inside
1852 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1853 VESA. If you have PCI, say Y, otherwise N.
1856 prompt "PCI access mode"
1857 depends on X86_32 && PCI
1860 On PCI systems, the BIOS can be used to detect the PCI devices and
1861 determine their configuration. However, some old PCI motherboards
1862 have BIOS bugs and may crash if this is done. Also, some embedded
1863 PCI-based systems don't have any BIOS at all. Linux can also try to
1864 detect the PCI hardware directly without using the BIOS.
1866 With this option, you can specify how Linux should detect the
1867 PCI devices. If you choose "BIOS", the BIOS will be used,
1868 if you choose "Direct", the BIOS won't be used, and if you
1869 choose "MMConfig", then PCI Express MMCONFIG will be used.
1870 If you choose "Any", the kernel will try MMCONFIG, then the
1871 direct access method and falls back to the BIOS if that doesn't
1872 work. If unsure, go with the default, which is "Any".
1877 config PCI_GOMMCONFIG
1894 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1896 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1899 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1903 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1907 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1914 bool "Support mmconfig PCI config space access"
1915 depends on X86_64 && PCI && ACPI
1917 config PCI_CNB20LE_QUIRK
1918 bool "Read CNB20LE Host Bridge Windows"
1921 Read the PCI windows out of the CNB20LE host bridge. This allows
1922 PCI hotplug to work on systems with the CNB20LE chipset which do
1926 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1927 depends on PCI_MSI && ACPI && EXPERIMENTAL
1929 DMA remapping (DMAR) devices support enables independent address
1930 translations for Direct Memory Access (DMA) from devices.
1931 These DMA remapping devices are reported via ACPI tables
1932 and include PCI device scope covered by these DMA
1935 config DMAR_DEFAULT_ON
1937 prompt "Enable DMA Remapping Devices by default"
1940 Selecting this option will enable a DMAR device at boot time if
1941 one is found. If this option is not selected, DMAR support can
1942 be enabled by passing intel_iommu=on to the kernel. It is
1943 recommended you say N here while the DMAR code remains
1946 config DMAR_BROKEN_GFX_WA
1947 bool "Workaround broken graphics drivers (going away soon)"
1948 depends on DMAR && BROKEN
1950 Current Graphics drivers tend to use physical address
1951 for DMA and avoid using DMA APIs. Setting this config
1952 option permits the IOMMU driver to set a unity map for
1953 all the OS-visible memory. Hence the driver can continue
1954 to use physical addresses for DMA, at least until this
1955 option is removed in the 2.6.32 kernel.
1957 config DMAR_FLOPPY_WA
1961 Floppy disk drivers are known to bypass DMA API calls
1962 thereby failing to work when IOMMU is enabled. This
1963 workaround will setup a 1:1 mapping for the first
1964 16MiB to make floppy (an ISA device) work.
1967 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1968 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1970 Supports Interrupt remapping for IO-APIC and MSI devices.
1971 To use x2apic mode in the CPU's which support x2APIC enhancements or
1972 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1974 source "drivers/pci/pcie/Kconfig"
1976 source "drivers/pci/Kconfig"
1978 # x86_64 have no ISA slots, but do have ISA-style DMA.
1987 Find out whether you have ISA slots on your motherboard. ISA is the
1988 name of a bus system, i.e. the way the CPU talks to the other stuff
1989 inside your box. Other bus systems are PCI, EISA, MicroChannel
1990 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1991 newer boards don't support it. If you have ISA, say Y, otherwise N.
1997 The Extended Industry Standard Architecture (EISA) bus was
1998 developed as an open alternative to the IBM MicroChannel bus.
2000 The EISA bus provided some of the features of the IBM MicroChannel
2001 bus while maintaining backward compatibility with cards made for
2002 the older ISA bus. The EISA bus saw limited use between 1988 and
2003 1995 when it was made obsolete by the PCI bus.
2005 Say Y here if you are building a kernel for an EISA-based machine.
2009 source "drivers/eisa/Kconfig"
2014 MicroChannel Architecture is found in some IBM PS/2 machines and
2015 laptops. It is a bus system similar to PCI or ISA. See
2016 <file:Documentation/mca.txt> (and especially the web page given
2017 there) before attempting to build an MCA bus kernel.
2019 source "drivers/mca/Kconfig"
2022 tristate "NatSemi SCx200 support"
2024 This provides basic support for National Semiconductor's
2025 (now AMD's) Geode processors. The driver probes for the
2026 PCI-IDs of several on-chip devices, so its a good dependency
2027 for other scx200_* drivers.
2029 If compiled as a module, the driver is named scx200.
2031 config SCx200HR_TIMER
2032 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2036 This driver provides a clocksource built upon the on-chip
2037 27MHz high-resolution timer. Its also a workaround for
2038 NSC Geode SC-1100's buggy TSC, which loses time when the
2039 processor goes idle (as is done by the scheduler). The
2040 other workaround is idle=poll boot option.
2043 bool "One Laptop Per Child support"
2045 select OLPC_OPENFIRMWARE
2047 Add support for detecting the unique features of the OLPC
2051 tristate "OLPC XO-1 support"
2052 depends on OLPC && PCI
2054 Add support for non-essential features of the OLPC XO-1 laptop.
2056 config OLPC_OPENFIRMWARE
2057 bool "Support for OLPC's Open Firmware"
2058 depends on !X86_64 && !X86_PAE
2061 This option adds support for the implementation of Open Firmware
2062 that is used on the OLPC XO-1 Children's Machine.
2063 If unsure, say N here.
2069 depends on CPU_SUP_AMD && PCI
2071 source "drivers/pcmcia/Kconfig"
2073 source "drivers/pci/hotplug/Kconfig"
2078 menu "Executable file formats / Emulations"
2080 source "fs/Kconfig.binfmt"
2082 config IA32_EMULATION
2083 bool "IA32 Emulation"
2085 select COMPAT_BINFMT_ELF
2087 Include code to run 32-bit programs under a 64-bit kernel. You should
2088 likely turn this on, unless you're 100% sure that you don't have any
2089 32-bit programs left.
2092 tristate "IA32 a.out support"
2093 depends on IA32_EMULATION
2095 Support old a.out binaries in the 32bit emulation.
2099 depends on IA32_EMULATION
2101 config COMPAT_FOR_U64_ALIGNMENT
2105 config SYSVIPC_COMPAT
2107 depends on COMPAT && SYSVIPC
2112 config HAVE_ATOMIC_IOMAP
2116 config HAVE_TEXT_POKE_SMP
2118 select STOP_MACHINE if SMP
2120 source "net/Kconfig"
2122 source "drivers/Kconfig"
2124 source "drivers/firmware/Kconfig"
2128 source "arch/x86/Kconfig.debug"
2130 source "security/Kconfig"
2132 source "crypto/Kconfig"
2134 source "arch/x86/kvm/Kconfig"
2136 source "lib/Kconfig"
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