3 bool "64-bit kernel" if ARCH = "x86"
4 default ARCH = "x86_64"
6 Say yes to build a 64-bit kernel - formerly known as x86_64
7 Say no to build a 32-bit kernel - formerly known as i386
19 select HAVE_AOUT if X86_32
20 select HAVE_UNSTABLE_SCHED_CLOCK
23 select HAVE_PCSPKR_PLATFORM
24 select HAVE_PERF_EVENTS
26 select HAVE_IOREMAP_PROT
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
32 select HAVE_KRETPROBES
34 select HAVE_FTRACE_MCOUNT_RECORD
35 select HAVE_C_RECORDMCOUNT
36 select HAVE_DYNAMIC_FTRACE
37 select HAVE_FUNCTION_TRACER
38 select HAVE_FUNCTION_GRAPH_TRACER
39 select HAVE_FUNCTION_GRAPH_FP_TEST
40 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
41 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
42 select HAVE_SYSCALL_TRACEPOINTS
45 select HAVE_ARCH_TRACEHOOK
46 select HAVE_GENERIC_DMA_COHERENT if X86_32
47 select HAVE_EFFICIENT_UNALIGNED_ACCESS
48 select USER_STACKTRACE_SUPPORT
49 select HAVE_REGS_AND_STACK_ACCESS_API
50 select HAVE_DMA_API_DEBUG
51 select HAVE_KERNEL_GZIP
52 select HAVE_KERNEL_BZIP2
53 select HAVE_KERNEL_LZMA
55 select HAVE_KERNEL_LZO
56 select HAVE_HW_BREAKPOINT
57 select HAVE_MIXED_BREAKPOINTS_REGS
59 select HAVE_PERF_EVENTS_NMI
61 select HAVE_ARCH_KMEMCHECK
62 select HAVE_USER_RETURN_NOTIFIER
63 select HAVE_ARCH_JUMP_LABEL
64 select HAVE_TEXT_POKE_SMP
65 select HAVE_GENERIC_HARDIRQS
66 select HAVE_SPARSE_IRQ
67 select GENERIC_FIND_FIRST_BIT
68 select GENERIC_IRQ_PROBE
69 select GENERIC_PENDING_IRQ if SMP
70 select GENERIC_IRQ_SHOW
71 select IRQ_FORCED_THREADING
72 select USE_GENERIC_SMP_HELPERS if SMP
73 select HAVE_BPF_JIT if (X86_64 && NET)
76 config INSTRUCTION_DECODER
77 def_bool (KPROBES || PERF_EVENTS)
81 default "elf32-i386" if X86_32
82 default "elf64-x86-64" if X86_64
86 default "arch/x86/configs/i386_defconfig" if X86_32
87 default "arch/x86/configs/x86_64_defconfig" if X86_64
89 config GENERIC_CMOS_UPDATE
92 config CLOCKSOURCE_WATCHDOG
95 config GENERIC_CLOCKEVENTS
98 config ARCH_CLOCKSOURCE_DATA
102 config GENERIC_CLOCKEVENTS_BROADCAST
104 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
106 config LOCKDEP_SUPPORT
109 config STACKTRACE_SUPPORT
112 config HAVE_LATENCYTOP_SUPPORT
119 bool "DMA memory allocation support" if EXPERT
122 DMA memory allocation support allows devices with less than 32-bit
123 addressing to allocate within the first 16MB of address space.
124 Disable if no such devices will be used.
131 config NEED_DMA_MAP_STATE
132 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
134 config NEED_SG_DMA_LENGTH
137 config GENERIC_ISA_DMA
146 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
148 config GENERIC_BUG_RELATIVE_POINTERS
151 config GENERIC_HWEIGHT
157 config ARCH_MAY_HAVE_PC_FDC
160 config RWSEM_GENERIC_SPINLOCK
163 config RWSEM_XCHGADD_ALGORITHM
166 config ARCH_HAS_CPU_IDLE_WAIT
169 config GENERIC_CALIBRATE_DELAY
172 config GENERIC_TIME_VSYSCALL
176 config ARCH_HAS_CPU_RELAX
179 config ARCH_HAS_DEFAULT_IDLE
182 config ARCH_HAS_CACHE_LINE_SIZE
185 config HAVE_SETUP_PER_CPU_AREA
188 config NEED_PER_CPU_EMBED_FIRST_CHUNK
191 config NEED_PER_CPU_PAGE_FIRST_CHUNK
194 config HAVE_CPUMASK_OF_CPU_MAP
197 config ARCH_HIBERNATION_POSSIBLE
200 config ARCH_SUSPEND_POSSIBLE
207 config ARCH_POPULATES_NODE_MAP
214 config ARCH_SUPPORTS_OPTIMIZED_INLINING
217 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
220 config HAVE_INTEL_TXT
222 depends on EXPERIMENTAL && DMAR && ACPI
226 depends on X86_32 && SMP
230 depends on X86_64 && SMP
236 config X86_32_LAZY_GS
238 depends on X86_32 && !CC_STACKPROTECTOR
240 config ARCH_HWEIGHT_CFLAGS
242 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
243 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
248 config ARCH_CPU_PROBE_RELEASE
250 depends on HOTPLUG_CPU
252 source "init/Kconfig"
253 source "kernel/Kconfig.freezer"
255 menu "Processor type and features"
257 source "kernel/time/Kconfig"
260 bool "Symmetric multi-processing support"
262 This enables support for systems with more than one CPU. If you have
263 a system with only one CPU, like most personal computers, say N. If
264 you have a system with more than one CPU, say Y.
266 If you say N here, the kernel will run on single and multiprocessor
267 machines, but will use only one CPU of a multiprocessor machine. If
268 you say Y here, the kernel will run on many, but not all,
269 singleprocessor machines. On a singleprocessor machine, the kernel
270 will run faster if you say N here.
272 Note that if you say Y here and choose architecture "586" or
273 "Pentium" under "Processor family", the kernel will not work on 486
274 architectures. Similarly, multiprocessor kernels for the "PPro"
275 architecture may not work on all Pentium based boards.
277 People using multiprocessor machines who say Y here should also say
278 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
279 Management" code will be disabled if you say Y here.
281 See also <file:Documentation/i386/IO-APIC.txt>,
282 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
283 <http://www.tldp.org/docs.html#howto>.
285 If you don't know what to do here, say N.
288 bool "Support x2apic"
289 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
291 This enables x2apic support on CPUs that have this feature.
293 This allows 32-bit apic IDs (so it can support very large systems),
294 and accesses the local apic via MSRs not via mmio.
296 If you don't know what to do here, say N.
299 bool "Enable MPS table" if ACPI
301 depends on X86_LOCAL_APIC
303 For old smp systems that do not have proper acpi support. Newer systems
304 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
307 bool "Support for big SMP systems with more than 8 CPUs"
308 depends on X86_32 && SMP
310 This option is needed for the systems that have more than 8 CPUs
313 config X86_EXTENDED_PLATFORM
314 bool "Support for extended (non-PC) x86 platforms"
317 If you disable this option then the kernel will only support
318 standard PC platforms. (which covers the vast majority of
321 If you enable this option then you'll be able to select support
322 for the following (non-PC) 32 bit x86 platforms:
326 SGI 320/540 (Visual Workstation)
327 Summit/EXA (IBM x440)
328 Unisys ES7000 IA32 series
329 Moorestown MID devices
331 If you have one of these systems, or if you want to build a
332 generic distribution kernel, say Y here - otherwise say N.
336 config X86_EXTENDED_PLATFORM
337 bool "Support for extended (non-PC) x86 platforms"
340 If you disable this option then the kernel will only support
341 standard PC platforms. (which covers the vast majority of
344 If you enable this option then you'll be able to select support
345 for the following (non-PC) 64 bit x86 platforms:
349 If you have one of these systems, or if you want to build a
350 generic distribution kernel, say Y here - otherwise say N.
352 # This is an alphabetically sorted list of 64 bit extended platforms
353 # Please maintain the alphabetic order if and when there are additions
357 select PARAVIRT_GUEST
359 depends on X86_64 && PCI
360 depends on X86_EXTENDED_PLATFORM
362 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
363 supposed to run on these EM64T-based machines. Only choose this option
364 if you have one of these machines.
367 bool "SGI Ultraviolet"
369 depends on X86_EXTENDED_PLATFORM
371 depends on X86_X2APIC
373 This option is needed in order to support SGI Ultraviolet systems.
374 If you don't have one of these, you should say N here.
376 # Following is an alphabetically sorted list of 32 bit extended platforms
377 # Please maintain the alphabetic order if and when there are additions
380 bool "CE4100 TV platform"
382 depends on PCI_GODIRECT
384 depends on X86_EXTENDED_PLATFORM
385 select X86_REBOOTFIXUPS
387 select OF_EARLY_FLATTREE
389 Select for the Intel CE media processor (CE4100) SOC.
390 This option compiles in support for the CE4100 SOC for settop
391 boxes and media devices.
394 bool "Intel MID platform support"
396 depends on X86_EXTENDED_PLATFORM
398 Select to build a kernel capable of supporting Intel MID platform
399 systems which do not have the PCI legacy interfaces (Moorestown,
400 Medfield). If you are building for a PC class system say N here.
405 bool "Moorestown MID platform"
408 depends on X86_IO_APIC
413 select X86_PLATFORM_DEVICES
415 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
416 Internet Device(MID) platform. Moorestown consists of two chips:
417 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
418 Unlike standard x86 PCs, Moorestown does not have many legacy devices
419 nor standard legacy replacement devices/features. e.g. Moorestown does
420 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
425 bool "RDC R-321x SoC"
427 depends on X86_EXTENDED_PLATFORM
429 select X86_REBOOTFIXUPS
431 This option is needed for RDC R-321x system-on-chip, also known
433 If you don't have one of these chips, you should say N here.
435 config X86_32_NON_STANDARD
436 bool "Support non-standard 32-bit SMP architectures"
437 depends on X86_32 && SMP
438 depends on X86_EXTENDED_PLATFORM
440 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
441 subarchitectures. It is intended for a generic binary kernel.
442 if you select them all, kernel will probe it one by one. and will
445 # Alphabetically sorted list of Non standard 32 bit platforms
448 bool "NUMAQ (IBM/Sequent)"
449 depends on X86_32_NON_STANDARD
454 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
455 NUMA multiquad box. This changes the way that processors are
456 bootstrapped, and uses Clustered Logical APIC addressing mode instead
457 of Flat Logical. You will need a new lynxer.elf file to flash your
458 firmware with - send email to <Martin.Bligh@us.ibm.com>.
460 config X86_SUPPORTS_MEMORY_FAILURE
462 # MCE code calls memory_failure():
464 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
465 depends on !X86_NUMAQ
466 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
467 depends on X86_64 || !SPARSEMEM
468 select ARCH_SUPPORTS_MEMORY_FAILURE
471 bool "SGI 320/540 (Visual Workstation)"
472 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
473 depends on X86_32_NON_STANDARD
475 The SGI Visual Workstation series is an IA32-based workstation
476 based on SGI systems chips with some legacy PC hardware attached.
478 Say Y here to create a kernel to run on the SGI 320 or 540.
480 A kernel compiled for the Visual Workstation will run on general
481 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
484 bool "Summit/EXA (IBM x440)"
485 depends on X86_32_NON_STANDARD
487 This option is needed for IBM systems that use the Summit/EXA chipset.
488 In particular, it is needed for the x440.
491 bool "Unisys ES7000 IA32 series"
492 depends on X86_32_NON_STANDARD && X86_BIGSMP
494 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
495 supposed to run on an IA32-based Unisys ES7000 system.
498 tristate "Eurobraille/Iris poweroff module"
501 The Iris machines from EuroBraille do not have APM or ACPI support
502 to shut themselves down properly. A special I/O sequence is
503 needed to do so, which is what this module does at
506 This is only for Iris machines from EuroBraille.
510 config SCHED_OMIT_FRAME_POINTER
512 prompt "Single-depth WCHAN output"
515 Calculate simpler /proc/<PID>/wchan values. If this option
516 is disabled then wchan values will recurse back to the
517 caller function. This provides more accurate wchan values,
518 at the expense of slightly more scheduling overhead.
520 If in doubt, say "Y".
522 menuconfig PARAVIRT_GUEST
523 bool "Paravirtualized guest support"
525 Say Y here to get to see options related to running Linux under
526 various hypervisors. This option alone does not add any kernel code.
528 If you say N, all options in this submenu will be skipped and disabled.
532 config PARAVIRT_TIME_ACCOUNTING
533 bool "Paravirtual steal time accounting"
537 Select this option to enable fine granularity task steal time
538 accounting. Time spent executing other tasks in parallel with
539 the current vCPU is discounted from the vCPU power. To account for
540 that, there can be a small performance impact.
542 If in doubt, say N here.
544 source "arch/x86/xen/Kconfig"
547 bool "KVM paravirtualized clock"
549 select PARAVIRT_CLOCK
551 Turning on this option will allow you to run a paravirtualized clock
552 when running over the KVM hypervisor. Instead of relying on a PIT
553 (or probably other) emulation by the underlying device model, the host
554 provides the guest with timing infrastructure such as time of day, and
558 bool "KVM Guest support"
561 This option enables various optimizations for running under the KVM
564 source "arch/x86/lguest/Kconfig"
567 bool "Enable paravirtualization code"
569 This changes the kernel so it can modify itself when it is run
570 under a hypervisor, potentially improving performance significantly
571 over full virtualization. However, when run without a hypervisor
572 the kernel is theoretically slower and slightly larger.
574 config PARAVIRT_SPINLOCKS
575 bool "Paravirtualization layer for spinlocks"
576 depends on PARAVIRT && SMP && EXPERIMENTAL
578 Paravirtualized spinlocks allow a pvops backend to replace the
579 spinlock implementation with something virtualization-friendly
580 (for example, block the virtual CPU rather than spinning).
582 Unfortunately the downside is an up to 5% performance hit on
583 native kernels, with various workloads.
585 If you are unsure how to answer this question, answer N.
587 config PARAVIRT_CLOCK
592 config PARAVIRT_DEBUG
593 bool "paravirt-ops debugging"
594 depends on PARAVIRT && DEBUG_KERNEL
596 Enable to debug paravirt_ops internals. Specifically, BUG if
597 a paravirt_op is missing when it is called.
605 This option adds a kernel parameter 'memtest', which allows memtest
607 memtest=0, mean disabled; -- default
608 memtest=1, mean do 1 test pattern;
610 memtest=4, mean do 4 test patterns.
611 If you are unsure how to answer this question, answer N.
613 config X86_SUMMIT_NUMA
615 depends on X86_32 && NUMA && X86_32_NON_STANDARD
617 config X86_CYCLONE_TIMER
619 depends on X86_32_NON_STANDARD
621 source "arch/x86/Kconfig.cpu"
625 prompt "HPET Timer Support" if X86_32
627 Use the IA-PC HPET (High Precision Event Timer) to manage
628 time in preference to the PIT and RTC, if a HPET is
630 HPET is the next generation timer replacing legacy 8254s.
631 The HPET provides a stable time base on SMP
632 systems, unlike the TSC, but it is more expensive to access,
633 as it is off-chip. You can find the HPET spec at
634 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
636 You can safely choose Y here. However, HPET will only be
637 activated if the platform and the BIOS support this feature.
638 Otherwise the 8254 will be used for timing services.
640 Choose N to continue using the legacy 8254 timer.
642 config HPET_EMULATE_RTC
644 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
648 prompt "Langwell APB Timer Support" if X86_MRST
651 APB timer is the replacement for 8254, HPET on X86 MID platforms.
652 The APBT provides a stable time base on SMP
653 systems, unlike the TSC, but it is more expensive to access,
654 as it is off-chip. APB timers are always running regardless of CPU
655 C states, they are used as per CPU clockevent device when possible.
657 # Mark as expert because too many people got it wrong.
658 # The code disables itself when not needed.
661 bool "Enable DMI scanning" if EXPERT
663 Enabled scanning of DMI to identify machine quirks. Say Y
664 here unless you have verified that your setup is not
665 affected by entries in the DMI blacklist. Required by PNP
669 bool "GART IOMMU support" if EXPERT
672 depends on X86_64 && PCI && AMD_NB
674 Support for full DMA access of devices with 32bit memory access only
675 on systems with more than 3GB. This is usually needed for USB,
676 sound, many IDE/SATA chipsets and some other devices.
677 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
678 based hardware IOMMU and a software bounce buffer based IOMMU used
679 on Intel systems and as fallback.
680 The code is only active when needed (enough memory and limited
681 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
685 bool "IBM Calgary IOMMU support"
687 depends on X86_64 && PCI && EXPERIMENTAL
689 Support for hardware IOMMUs in IBM's xSeries x366 and x460
690 systems. Needed to run systems with more than 3GB of memory
691 properly with 32-bit PCI devices that do not support DAC
692 (Double Address Cycle). Calgary also supports bus level
693 isolation, where all DMAs pass through the IOMMU. This
694 prevents them from going anywhere except their intended
695 destination. This catches hard-to-find kernel bugs and
696 mis-behaving drivers and devices that do not use the DMA-API
697 properly to set up their DMA buffers. The IOMMU can be
698 turned off at boot time with the iommu=off parameter.
699 Normally the kernel will make the right choice by itself.
702 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
704 prompt "Should Calgary be enabled by default?"
705 depends on CALGARY_IOMMU
707 Should Calgary be enabled by default? if you choose 'y', Calgary
708 will be used (if it exists). If you choose 'n', Calgary will not be
709 used even if it exists. If you choose 'n' and would like to use
710 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
713 # need this always selected by IOMMU for the VIA workaround
717 Support for software bounce buffers used on x86-64 systems
718 which don't have a hardware IOMMU (e.g. the current generation
719 of Intel's x86-64 CPUs). Using this PCI devices which can only
720 access 32-bits of memory can be used on systems with more than
721 3 GB of memory. If unsure, say Y.
724 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
727 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
728 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
729 select CPUMASK_OFFSTACK
731 Enable maximum number of CPUS and NUMA Nodes for this architecture.
735 int "Maximum number of CPUs" if SMP && !MAXSMP
736 range 2 8 if SMP && X86_32 && !X86_BIGSMP
737 range 2 512 if SMP && !MAXSMP
739 default "4096" if MAXSMP
740 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
743 This allows you to specify the maximum number of CPUs which this
744 kernel will support. The maximum supported value is 512 and the
745 minimum value which makes sense is 2.
747 This is purely to save memory - each supported CPU adds
748 approximately eight kilobytes to the kernel image.
751 bool "SMT (Hyperthreading) scheduler support"
754 SMT scheduler support improves the CPU scheduler's decision making
755 when dealing with Intel Pentium 4 chips with HyperThreading at a
756 cost of slightly increased overhead in some places. If unsure say
761 prompt "Multi-core scheduler support"
764 Multi-core scheduler support improves the CPU scheduler's decision
765 making when dealing with multi-core CPU chips at a cost of slightly
766 increased overhead in some places. If unsure say N here.
768 config IRQ_TIME_ACCOUNTING
769 bool "Fine granularity task level IRQ time accounting"
772 Select this option to enable fine granularity task irq time
773 accounting. This is done by reading a timestamp on each
774 transitions between softirq and hardirq state, so there can be a
775 small performance impact.
777 If in doubt, say N here.
779 source "kernel/Kconfig.preempt"
782 bool "Local APIC support on uniprocessors"
783 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
785 A local APIC (Advanced Programmable Interrupt Controller) is an
786 integrated interrupt controller in the CPU. If you have a single-CPU
787 system which has a processor with a local APIC, you can say Y here to
788 enable and use it. If you say Y here even though your machine doesn't
789 have a local APIC, then the kernel will still run with no slowdown at
790 all. The local APIC supports CPU-generated self-interrupts (timer,
791 performance counters), and the NMI watchdog which detects hard
795 bool "IO-APIC support on uniprocessors"
796 depends on X86_UP_APIC
798 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
799 SMP-capable replacement for PC-style interrupt controllers. Most
800 SMP systems and many recent uniprocessor systems have one.
802 If you have a single-CPU system with an IO-APIC, you can say Y here
803 to use it. If you say Y here even though your machine doesn't have
804 an IO-APIC, then the kernel will still run with no slowdown at all.
806 config X86_LOCAL_APIC
808 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
812 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
814 config X86_VISWS_APIC
816 depends on X86_32 && X86_VISWS
818 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
819 bool "Reroute for broken boot IRQs"
820 depends on X86_IO_APIC
822 This option enables a workaround that fixes a source of
823 spurious interrupts. This is recommended when threaded
824 interrupt handling is used on systems where the generation of
825 superfluous "boot interrupts" cannot be disabled.
827 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
828 entry in the chipset's IO-APIC is masked (as, e.g. the RT
829 kernel does during interrupt handling). On chipsets where this
830 boot IRQ generation cannot be disabled, this workaround keeps
831 the original IRQ line masked so that only the equivalent "boot
832 IRQ" is delivered to the CPUs. The workaround also tells the
833 kernel to set up the IRQ handler on the boot IRQ line. In this
834 way only one interrupt is delivered to the kernel. Otherwise
835 the spurious second interrupt may cause the kernel to bring
836 down (vital) interrupt lines.
838 Only affects "broken" chipsets. Interrupt sharing may be
839 increased on these systems.
842 bool "Machine Check / overheating reporting"
844 Machine Check support allows the processor to notify the
845 kernel if it detects a problem (e.g. overheating, data corruption).
846 The action the kernel takes depends on the severity of the problem,
847 ranging from warning messages to halting the machine.
851 prompt "Intel MCE features"
852 depends on X86_MCE && X86_LOCAL_APIC
854 Additional support for intel specific MCE features such as
859 prompt "AMD MCE features"
860 depends on X86_MCE && X86_LOCAL_APIC
862 Additional support for AMD specific MCE features such as
863 the DRAM Error Threshold.
865 config X86_ANCIENT_MCE
866 bool "Support for old Pentium 5 / WinChip machine checks"
867 depends on X86_32 && X86_MCE
869 Include support for machine check handling on old Pentium 5 or WinChip
870 systems. These typically need to be enabled explicitely on the command
873 config X86_MCE_THRESHOLD
874 depends on X86_MCE_AMD || X86_MCE_INTEL
877 config X86_MCE_INJECT
879 tristate "Machine check injector support"
881 Provide support for injecting machine checks for testing purposes.
882 If you don't know what a machine check is and you don't do kernel
883 QA it is safe to say n.
885 config X86_THERMAL_VECTOR
887 depends on X86_MCE_INTEL
890 bool "Enable VM86 support" if EXPERT
894 This option is required by programs like DOSEMU to run 16-bit legacy
895 code on X86 processors. It also may be needed by software like
896 XFree86 to initialize some video cards via BIOS. Disabling this
897 option saves about 6k.
900 tristate "Toshiba Laptop support"
903 This adds a driver to safely access the System Management Mode of
904 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
905 not work on models with a Phoenix BIOS. The System Management Mode
906 is used to set the BIOS and power saving options on Toshiba portables.
908 For information on utilities to make use of this driver see the
909 Toshiba Linux utilities web site at:
910 <http://www.buzzard.org.uk/toshiba/>.
912 Say Y if you intend to run this kernel on a Toshiba portable.
916 tristate "Dell laptop support"
919 This adds a driver to safely access the System Management Mode
920 of the CPU on the Dell Inspiron 8000. The System Management Mode
921 is used to read cpu temperature and cooling fan status and to
922 control the fans on the I8K portables.
924 This driver has been tested only on the Inspiron 8000 but it may
925 also work with other Dell laptops. You can force loading on other
926 models by passing the parameter `force=1' to the module. Use at
929 For information on utilities to make use of this driver see the
930 I8K Linux utilities web site at:
931 <http://people.debian.org/~dz/i8k/>
933 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
936 config X86_REBOOTFIXUPS
937 bool "Enable X86 board specific fixups for reboot"
940 This enables chipset and/or board specific fixups to be done
941 in order to get reboot to work correctly. This is only needed on
942 some combinations of hardware and BIOS. The symptom, for which
943 this config is intended, is when reboot ends with a stalled/hung
946 Currently, the only fixup is for the Geode machines using
947 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
949 Say Y if you want to enable the fixup. Currently, it's safe to
950 enable this option even if you don't need it.
954 tristate "/dev/cpu/microcode - microcode support"
957 If you say Y here, you will be able to update the microcode on
958 certain Intel and AMD processors. The Intel support is for the
959 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
960 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
961 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
962 You will obviously need the actual microcode binary data itself
963 which is not shipped with the Linux kernel.
965 This option selects the general module only, you need to select
966 at least one vendor specific module as well.
968 To compile this driver as a module, choose M here: the
969 module will be called microcode.
971 config MICROCODE_INTEL
972 bool "Intel microcode patch loading support"
977 This options enables microcode patch loading support for Intel
980 For latest news and information on obtaining all the required
981 Intel ingredients for this driver, check:
982 <http://www.urbanmyth.org/microcode/>.
985 bool "AMD microcode patch loading support"
989 If you select this option, microcode patch loading support for AMD
990 processors will be enabled.
992 config MICROCODE_OLD_INTERFACE
997 tristate "/dev/cpu/*/msr - Model-specific register support"
999 This device gives privileged processes access to the x86
1000 Model-Specific Registers (MSRs). It is a character device with
1001 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1002 MSR accesses are directed to a specific CPU on multi-processor
1006 tristate "/dev/cpu/*/cpuid - CPU information support"
1008 This device gives processes access to the x86 CPUID instruction to
1009 be executed on a specific processor. It is a character device
1010 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1014 prompt "High Memory Support"
1015 default HIGHMEM64G if X86_NUMAQ
1021 depends on !X86_NUMAQ
1023 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1024 However, the address space of 32-bit x86 processors is only 4
1025 Gigabytes large. That means that, if you have a large amount of
1026 physical memory, not all of it can be "permanently mapped" by the
1027 kernel. The physical memory that's not permanently mapped is called
1030 If you are compiling a kernel which will never run on a machine with
1031 more than 1 Gigabyte total physical RAM, answer "off" here (default
1032 choice and suitable for most users). This will result in a "3GB/1GB"
1033 split: 3GB are mapped so that each process sees a 3GB virtual memory
1034 space and the remaining part of the 4GB virtual memory space is used
1035 by the kernel to permanently map as much physical memory as
1038 If the machine has between 1 and 4 Gigabytes physical RAM, then
1041 If more than 4 Gigabytes is used then answer "64GB" here. This
1042 selection turns Intel PAE (Physical Address Extension) mode on.
1043 PAE implements 3-level paging on IA32 processors. PAE is fully
1044 supported by Linux, PAE mode is implemented on all recent Intel
1045 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1046 then the kernel will not boot on CPUs that don't support PAE!
1048 The actual amount of total physical memory will either be
1049 auto detected or can be forced by using a kernel command line option
1050 such as "mem=256M". (Try "man bootparam" or see the documentation of
1051 your boot loader (lilo or loadlin) about how to pass options to the
1052 kernel at boot time.)
1054 If unsure, say "off".
1058 depends on !X86_NUMAQ
1060 Select this if you have a 32-bit processor and between 1 and 4
1061 gigabytes of physical RAM.
1065 depends on !M386 && !M486
1068 Select this if you have a 32-bit processor and more than 4
1069 gigabytes of physical RAM.
1074 depends on EXPERIMENTAL
1075 prompt "Memory split" if EXPERT
1079 Select the desired split between kernel and user memory.
1081 If the address range available to the kernel is less than the
1082 physical memory installed, the remaining memory will be available
1083 as "high memory". Accessing high memory is a little more costly
1084 than low memory, as it needs to be mapped into the kernel first.
1085 Note that increasing the kernel address space limits the range
1086 available to user programs, making the address space there
1087 tighter. Selecting anything other than the default 3G/1G split
1088 will also likely make your kernel incompatible with binary-only
1091 If you are not absolutely sure what you are doing, leave this
1095 bool "3G/1G user/kernel split"
1096 config VMSPLIT_3G_OPT
1098 bool "3G/1G user/kernel split (for full 1G low memory)"
1100 bool "2G/2G user/kernel split"
1101 config VMSPLIT_2G_OPT
1103 bool "2G/2G user/kernel split (for full 2G low memory)"
1105 bool "1G/3G user/kernel split"
1110 default 0xB0000000 if VMSPLIT_3G_OPT
1111 default 0x80000000 if VMSPLIT_2G
1112 default 0x78000000 if VMSPLIT_2G_OPT
1113 default 0x40000000 if VMSPLIT_1G
1119 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1122 bool "PAE (Physical Address Extension) Support"
1123 depends on X86_32 && !HIGHMEM4G
1125 PAE is required for NX support, and furthermore enables
1126 larger swapspace support for non-overcommit purposes. It
1127 has the cost of more pagetable lookup overhead, and also
1128 consumes more pagetable space per process.
1130 config ARCH_PHYS_ADDR_T_64BIT
1131 def_bool X86_64 || X86_PAE
1133 config ARCH_DMA_ADDR_T_64BIT
1134 def_bool X86_64 || HIGHMEM64G
1136 config DIRECT_GBPAGES
1137 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1141 Allow the kernel linear mapping to use 1GB pages on CPUs that
1142 support it. This can improve the kernel's performance a tiny bit by
1143 reducing TLB pressure. If in doubt, say "Y".
1145 # Common NUMA Features
1147 bool "Numa Memory Allocation and Scheduler Support"
1149 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1150 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1152 Enable NUMA (Non Uniform Memory Access) support.
1154 The kernel will try to allocate memory used by a CPU on the
1155 local memory controller of the CPU and add some more
1156 NUMA awareness to the kernel.
1158 For 64-bit this is recommended if the system is Intel Core i7
1159 (or later), AMD Opteron, or EM64T NUMA.
1161 For 32-bit this is only needed on (rare) 32-bit-only platforms
1162 that support NUMA topologies, such as NUMAQ / Summit, or if you
1163 boot a 32-bit kernel on a 64-bit NUMA platform.
1165 Otherwise, you should say N.
1167 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1168 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1172 prompt "Old style AMD Opteron NUMA detection"
1173 depends on X86_64 && NUMA && PCI
1175 Enable AMD NUMA node topology detection. You should say Y here if
1176 you have a multi processor AMD system. This uses an old method to
1177 read the NUMA configuration directly from the builtin Northbridge
1178 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1179 which also takes priority if both are compiled in.
1181 config X86_64_ACPI_NUMA
1183 prompt "ACPI NUMA detection"
1184 depends on X86_64 && NUMA && ACPI && PCI
1187 Enable ACPI SRAT based node topology detection.
1189 # Some NUMA nodes have memory ranges that span
1190 # other nodes. Even though a pfn is valid and
1191 # between a node's start and end pfns, it may not
1192 # reside on that node. See memmap_init_zone()
1194 config NODES_SPAN_OTHER_NODES
1196 depends on X86_64_ACPI_NUMA
1199 bool "NUMA emulation"
1202 Enable NUMA emulation. A flat machine will be split
1203 into virtual nodes when booted with "numa=fake=N", where N is the
1204 number of nodes. This is only useful for debugging.
1207 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1209 default "10" if MAXSMP
1210 default "6" if X86_64
1211 default "4" if X86_NUMAQ
1213 depends on NEED_MULTIPLE_NODES
1215 Specify the maximum number of NUMA Nodes available on the target
1216 system. Increases memory reserved to accommodate various tables.
1218 config HAVE_ARCH_BOOTMEM
1220 depends on X86_32 && NUMA
1222 config HAVE_ARCH_ALLOC_REMAP
1224 depends on X86_32 && NUMA
1226 config ARCH_HAVE_MEMORY_PRESENT
1228 depends on X86_32 && DISCONTIGMEM
1230 config NEED_NODE_MEMMAP_SIZE
1232 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1234 config ARCH_FLATMEM_ENABLE
1236 depends on X86_32 && !NUMA
1238 config ARCH_DISCONTIGMEM_ENABLE
1240 depends on NUMA && X86_32
1242 config ARCH_DISCONTIGMEM_DEFAULT
1244 depends on NUMA && X86_32
1246 config ARCH_SPARSEMEM_ENABLE
1248 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1249 select SPARSEMEM_STATIC if X86_32
1250 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1252 config ARCH_SPARSEMEM_DEFAULT
1256 config ARCH_SELECT_MEMORY_MODEL
1258 depends on ARCH_SPARSEMEM_ENABLE
1260 config ARCH_MEMORY_PROBE
1262 depends on MEMORY_HOTPLUG
1264 config ARCH_PROC_KCORE_TEXT
1266 depends on X86_64 && PROC_KCORE
1268 config ILLEGAL_POINTER_VALUE
1271 default 0xdead000000000000 if X86_64
1276 bool "Allocate 3rd-level pagetables from highmem"
1279 The VM uses one page table entry for each page of physical memory.
1280 For systems with a lot of RAM, this can be wasteful of precious
1281 low memory. Setting this option will put user-space page table
1282 entries in high memory.
1284 config X86_CHECK_BIOS_CORRUPTION
1285 bool "Check for low memory corruption"
1287 Periodically check for memory corruption in low memory, which
1288 is suspected to be caused by BIOS. Even when enabled in the
1289 configuration, it is disabled at runtime. Enable it by
1290 setting "memory_corruption_check=1" on the kernel command
1291 line. By default it scans the low 64k of memory every 60
1292 seconds; see the memory_corruption_check_size and
1293 memory_corruption_check_period parameters in
1294 Documentation/kernel-parameters.txt to adjust this.
1296 When enabled with the default parameters, this option has
1297 almost no overhead, as it reserves a relatively small amount
1298 of memory and scans it infrequently. It both detects corruption
1299 and prevents it from affecting the running system.
1301 It is, however, intended as a diagnostic tool; if repeatable
1302 BIOS-originated corruption always affects the same memory,
1303 you can use memmap= to prevent the kernel from using that
1306 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1307 bool "Set the default setting of memory_corruption_check"
1308 depends on X86_CHECK_BIOS_CORRUPTION
1311 Set whether the default state of memory_corruption_check is
1314 config X86_RESERVE_LOW
1315 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1319 Specify the amount of low memory to reserve for the BIOS.
1321 The first page contains BIOS data structures that the kernel
1322 must not use, so that page must always be reserved.
1324 By default we reserve the first 64K of physical RAM, as a
1325 number of BIOSes are known to corrupt that memory range
1326 during events such as suspend/resume or monitor cable
1327 insertion, so it must not be used by the kernel.
1329 You can set this to 4 if you are absolutely sure that you
1330 trust the BIOS to get all its memory reservations and usages
1331 right. If you know your BIOS have problems beyond the
1332 default 64K area, you can set this to 640 to avoid using the
1333 entire low memory range.
1335 If you have doubts about the BIOS (e.g. suspend/resume does
1336 not work or there's kernel crashes after certain hardware
1337 hotplug events) then you might want to enable
1338 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1339 typical corruption patterns.
1341 Leave this to the default value of 64 if you are unsure.
1343 config MATH_EMULATION
1345 prompt "Math emulation" if X86_32
1347 Linux can emulate a math coprocessor (used for floating point
1348 operations) if you don't have one. 486DX and Pentium processors have
1349 a math coprocessor built in, 486SX and 386 do not, unless you added
1350 a 487DX or 387, respectively. (The messages during boot time can
1351 give you some hints here ["man dmesg"].) Everyone needs either a
1352 coprocessor or this emulation.
1354 If you don't have a math coprocessor, you need to say Y here; if you
1355 say Y here even though you have a coprocessor, the coprocessor will
1356 be used nevertheless. (This behavior can be changed with the kernel
1357 command line option "no387", which comes handy if your coprocessor
1358 is broken. Try "man bootparam" or see the documentation of your boot
1359 loader (lilo or loadlin) about how to pass options to the kernel at
1360 boot time.) This means that it is a good idea to say Y here if you
1361 intend to use this kernel on different machines.
1363 More information about the internals of the Linux math coprocessor
1364 emulation can be found in <file:arch/x86/math-emu/README>.
1366 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1367 kernel, it won't hurt.
1371 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1373 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1374 the Memory Type Range Registers (MTRRs) may be used to control
1375 processor access to memory ranges. This is most useful if you have
1376 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1377 allows bus write transfers to be combined into a larger transfer
1378 before bursting over the PCI/AGP bus. This can increase performance
1379 of image write operations 2.5 times or more. Saying Y here creates a
1380 /proc/mtrr file which may be used to manipulate your processor's
1381 MTRRs. Typically the X server should use this.
1383 This code has a reasonably generic interface so that similar
1384 control registers on other processors can be easily supported
1387 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1388 Registers (ARRs) which provide a similar functionality to MTRRs. For
1389 these, the ARRs are used to emulate the MTRRs.
1390 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1391 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1392 write-combining. All of these processors are supported by this code
1393 and it makes sense to say Y here if you have one of them.
1395 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1396 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1397 can lead to all sorts of problems, so it's good to say Y here.
1399 You can safely say Y even if your machine doesn't have MTRRs, you'll
1400 just add about 9 KB to your kernel.
1402 See <file:Documentation/x86/mtrr.txt> for more information.
1404 config MTRR_SANITIZER
1406 prompt "MTRR cleanup support"
1409 Convert MTRR layout from continuous to discrete, so X drivers can
1410 add writeback entries.
1412 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1413 The largest mtrr entry size for a continuous block can be set with
1418 config MTRR_SANITIZER_ENABLE_DEFAULT
1419 int "MTRR cleanup enable value (0-1)"
1422 depends on MTRR_SANITIZER
1424 Enable mtrr cleanup default value
1426 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1427 int "MTRR cleanup spare reg num (0-7)"
1430 depends on MTRR_SANITIZER
1432 mtrr cleanup spare entries default, it can be changed via
1433 mtrr_spare_reg_nr=N on the kernel command line.
1437 prompt "x86 PAT support" if EXPERT
1440 Use PAT attributes to setup page level cache control.
1442 PATs are the modern equivalents of MTRRs and are much more
1443 flexible than MTRRs.
1445 Say N here if you see bootup problems (boot crash, boot hang,
1446 spontaneous reboots) or a non-working video driver.
1450 config ARCH_USES_PG_UNCACHED
1455 bool "EFI runtime service support"
1458 This enables the kernel to use EFI runtime services that are
1459 available (such as the EFI variable services).
1461 This option is only useful on systems that have EFI firmware.
1462 In addition, you should use the latest ELILO loader available
1463 at <http://elilo.sourceforge.net> in order to take advantage
1464 of EFI runtime services. However, even with this option, the
1465 resultant kernel should continue to boot on existing non-EFI
1470 prompt "Enable seccomp to safely compute untrusted bytecode"
1472 This kernel feature is useful for number crunching applications
1473 that may need to compute untrusted bytecode during their
1474 execution. By using pipes or other transports made available to
1475 the process as file descriptors supporting the read/write
1476 syscalls, it's possible to isolate those applications in
1477 their own address space using seccomp. Once seccomp is
1478 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1479 and the task is only allowed to execute a few safe syscalls
1480 defined by each seccomp mode.
1482 If unsure, say Y. Only embedded should say N here.
1484 config CC_STACKPROTECTOR
1485 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1487 This option turns on the -fstack-protector GCC feature. This
1488 feature puts, at the beginning of functions, a canary value on
1489 the stack just before the return address, and validates
1490 the value just before actually returning. Stack based buffer
1491 overflows (that need to overwrite this return address) now also
1492 overwrite the canary, which gets detected and the attack is then
1493 neutralized via a kernel panic.
1495 This feature requires gcc version 4.2 or above, or a distribution
1496 gcc with the feature backported. Older versions are automatically
1497 detected and for those versions, this configuration option is
1498 ignored. (and a warning is printed during bootup)
1500 source kernel/Kconfig.hz
1503 bool "kexec system call"
1505 kexec is a system call that implements the ability to shutdown your
1506 current kernel, and to start another kernel. It is like a reboot
1507 but it is independent of the system firmware. And like a reboot
1508 you can start any kernel with it, not just Linux.
1510 The name comes from the similarity to the exec system call.
1512 It is an ongoing process to be certain the hardware in a machine
1513 is properly shutdown, so do not be surprised if this code does not
1514 initially work for you. It may help to enable device hotplugging
1515 support. As of this writing the exact hardware interface is
1516 strongly in flux, so no good recommendation can be made.
1519 bool "kernel crash dumps"
1520 depends on X86_64 || (X86_32 && HIGHMEM)
1522 Generate crash dump after being started by kexec.
1523 This should be normally only set in special crash dump kernels
1524 which are loaded in the main kernel with kexec-tools into
1525 a specially reserved region and then later executed after
1526 a crash by kdump/kexec. The crash dump kernel must be compiled
1527 to a memory address not used by the main kernel or BIOS using
1528 PHYSICAL_START, or it must be built as a relocatable image
1529 (CONFIG_RELOCATABLE=y).
1530 For more details see Documentation/kdump/kdump.txt
1533 bool "kexec jump (EXPERIMENTAL)"
1534 depends on EXPERIMENTAL
1535 depends on KEXEC && HIBERNATION
1537 Jump between original kernel and kexeced kernel and invoke
1538 code in physical address mode via KEXEC
1540 config PHYSICAL_START
1541 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1544 This gives the physical address where the kernel is loaded.
1546 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1547 bzImage will decompress itself to above physical address and
1548 run from there. Otherwise, bzImage will run from the address where
1549 it has been loaded by the boot loader and will ignore above physical
1552 In normal kdump cases one does not have to set/change this option
1553 as now bzImage can be compiled as a completely relocatable image
1554 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1555 address. This option is mainly useful for the folks who don't want
1556 to use a bzImage for capturing the crash dump and want to use a
1557 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1558 to be specifically compiled to run from a specific memory area
1559 (normally a reserved region) and this option comes handy.
1561 So if you are using bzImage for capturing the crash dump,
1562 leave the value here unchanged to 0x1000000 and set
1563 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1564 for capturing the crash dump change this value to start of
1565 the reserved region. In other words, it can be set based on
1566 the "X" value as specified in the "crashkernel=YM@XM"
1567 command line boot parameter passed to the panic-ed
1568 kernel. Please take a look at Documentation/kdump/kdump.txt
1569 for more details about crash dumps.
1571 Usage of bzImage for capturing the crash dump is recommended as
1572 one does not have to build two kernels. Same kernel can be used
1573 as production kernel and capture kernel. Above option should have
1574 gone away after relocatable bzImage support is introduced. But it
1575 is present because there are users out there who continue to use
1576 vmlinux for dump capture. This option should go away down the
1579 Don't change this unless you know what you are doing.
1582 bool "Build a relocatable kernel"
1585 This builds a kernel image that retains relocation information
1586 so it can be loaded someplace besides the default 1MB.
1587 The relocations tend to make the kernel binary about 10% larger,
1588 but are discarded at runtime.
1590 One use is for the kexec on panic case where the recovery kernel
1591 must live at a different physical address than the primary
1594 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1595 it has been loaded at and the compile time physical address
1596 (CONFIG_PHYSICAL_START) is ignored.
1598 # Relocation on x86-32 needs some additional build support
1599 config X86_NEED_RELOCS
1601 depends on X86_32 && RELOCATABLE
1603 config PHYSICAL_ALIGN
1604 hex "Alignment value to which kernel should be aligned" if X86_32
1606 range 0x2000 0x1000000
1608 This value puts the alignment restrictions on physical address
1609 where kernel is loaded and run from. Kernel is compiled for an
1610 address which meets above alignment restriction.
1612 If bootloader loads the kernel at a non-aligned address and
1613 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1614 address aligned to above value and run from there.
1616 If bootloader loads the kernel at a non-aligned address and
1617 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1618 load address and decompress itself to the address it has been
1619 compiled for and run from there. The address for which kernel is
1620 compiled already meets above alignment restrictions. Hence the
1621 end result is that kernel runs from a physical address meeting
1622 above alignment restrictions.
1624 Don't change this unless you know what you are doing.
1627 bool "Support for hot-pluggable CPUs"
1628 depends on SMP && HOTPLUG
1630 Say Y here to allow turning CPUs off and on. CPUs can be
1631 controlled through /sys/devices/system/cpu.
1632 ( Note: power management support will enable this option
1633 automatically on SMP systems. )
1634 Say N if you want to disable CPU hotplug.
1638 prompt "Compat VDSO support"
1639 depends on X86_32 || IA32_EMULATION
1641 Map the 32-bit VDSO to the predictable old-style address too.
1643 Say N here if you are running a sufficiently recent glibc
1644 version (2.3.3 or later), to remove the high-mapped
1645 VDSO mapping and to exclusively use the randomized VDSO.
1650 bool "Built-in kernel command line"
1652 Allow for specifying boot arguments to the kernel at
1653 build time. On some systems (e.g. embedded ones), it is
1654 necessary or convenient to provide some or all of the
1655 kernel boot arguments with the kernel itself (that is,
1656 to not rely on the boot loader to provide them.)
1658 To compile command line arguments into the kernel,
1659 set this option to 'Y', then fill in the
1660 the boot arguments in CONFIG_CMDLINE.
1662 Systems with fully functional boot loaders (i.e. non-embedded)
1663 should leave this option set to 'N'.
1666 string "Built-in kernel command string"
1667 depends on CMDLINE_BOOL
1670 Enter arguments here that should be compiled into the kernel
1671 image and used at boot time. If the boot loader provides a
1672 command line at boot time, it is appended to this string to
1673 form the full kernel command line, when the system boots.
1675 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1676 change this behavior.
1678 In most cases, the command line (whether built-in or provided
1679 by the boot loader) should specify the device for the root
1682 config CMDLINE_OVERRIDE
1683 bool "Built-in command line overrides boot loader arguments"
1684 depends on CMDLINE_BOOL
1686 Set this option to 'Y' to have the kernel ignore the boot loader
1687 command line, and use ONLY the built-in command line.
1689 This is used to work around broken boot loaders. This should
1690 be set to 'N' under normal conditions.
1694 config ARCH_ENABLE_MEMORY_HOTPLUG
1696 depends on X86_64 || (X86_32 && HIGHMEM)
1698 config ARCH_ENABLE_MEMORY_HOTREMOVE
1700 depends on MEMORY_HOTPLUG
1702 config USE_PERCPU_NUMA_NODE_ID
1706 menu "Power management and ACPI options"
1708 config ARCH_HIBERNATION_HEADER
1710 depends on X86_64 && HIBERNATION
1712 source "kernel/power/Kconfig"
1714 source "drivers/acpi/Kconfig"
1716 source "drivers/sfi/Kconfig"
1720 depends on APM || APM_MODULE
1723 tristate "APM (Advanced Power Management) BIOS support"
1724 depends on X86_32 && PM_SLEEP
1726 APM is a BIOS specification for saving power using several different
1727 techniques. This is mostly useful for battery powered laptops with
1728 APM compliant BIOSes. If you say Y here, the system time will be
1729 reset after a RESUME operation, the /proc/apm device will provide
1730 battery status information, and user-space programs will receive
1731 notification of APM "events" (e.g. battery status change).
1733 If you select "Y" here, you can disable actual use of the APM
1734 BIOS by passing the "apm=off" option to the kernel at boot time.
1736 Note that the APM support is almost completely disabled for
1737 machines with more than one CPU.
1739 In order to use APM, you will need supporting software. For location
1740 and more information, read <file:Documentation/power/apm-acpi.txt>
1741 and the Battery Powered Linux mini-HOWTO, available from
1742 <http://www.tldp.org/docs.html#howto>.
1744 This driver does not spin down disk drives (see the hdparm(8)
1745 manpage ("man 8 hdparm") for that), and it doesn't turn off
1746 VESA-compliant "green" monitors.
1748 This driver does not support the TI 4000M TravelMate and the ACER
1749 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1750 desktop machines also don't have compliant BIOSes, and this driver
1751 may cause those machines to panic during the boot phase.
1753 Generally, if you don't have a battery in your machine, there isn't
1754 much point in using this driver and you should say N. If you get
1755 random kernel OOPSes or reboots that don't seem to be related to
1756 anything, try disabling/enabling this option (or disabling/enabling
1759 Some other things you should try when experiencing seemingly random,
1762 1) make sure that you have enough swap space and that it is
1764 2) pass the "no-hlt" option to the kernel
1765 3) switch on floating point emulation in the kernel and pass
1766 the "no387" option to the kernel
1767 4) pass the "floppy=nodma" option to the kernel
1768 5) pass the "mem=4M" option to the kernel (thereby disabling
1769 all but the first 4 MB of RAM)
1770 6) make sure that the CPU is not over clocked.
1771 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1772 8) disable the cache from your BIOS settings
1773 9) install a fan for the video card or exchange video RAM
1774 10) install a better fan for the CPU
1775 11) exchange RAM chips
1776 12) exchange the motherboard.
1778 To compile this driver as a module, choose M here: the
1779 module will be called apm.
1783 config APM_IGNORE_USER_SUSPEND
1784 bool "Ignore USER SUSPEND"
1786 This option will ignore USER SUSPEND requests. On machines with a
1787 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1788 series notebooks, it is necessary to say Y because of a BIOS bug.
1790 config APM_DO_ENABLE
1791 bool "Enable PM at boot time"
1793 Enable APM features at boot time. From page 36 of the APM BIOS
1794 specification: "When disabled, the APM BIOS does not automatically
1795 power manage devices, enter the Standby State, enter the Suspend
1796 State, or take power saving steps in response to CPU Idle calls."
1797 This driver will make CPU Idle calls when Linux is idle (unless this
1798 feature is turned off -- see "Do CPU IDLE calls", below). This
1799 should always save battery power, but more complicated APM features
1800 will be dependent on your BIOS implementation. You may need to turn
1801 this option off if your computer hangs at boot time when using APM
1802 support, or if it beeps continuously instead of suspending. Turn
1803 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1804 T400CDT. This is off by default since most machines do fine without
1808 bool "Make CPU Idle calls when idle"
1810 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1811 On some machines, this can activate improved power savings, such as
1812 a slowed CPU clock rate, when the machine is idle. These idle calls
1813 are made after the idle loop has run for some length of time (e.g.,
1814 333 mS). On some machines, this will cause a hang at boot time or
1815 whenever the CPU becomes idle. (On machines with more than one CPU,
1816 this option does nothing.)
1818 config APM_DISPLAY_BLANK
1819 bool "Enable console blanking using APM"
1821 Enable console blanking using the APM. Some laptops can use this to
1822 turn off the LCD backlight when the screen blanker of the Linux
1823 virtual console blanks the screen. Note that this is only used by
1824 the virtual console screen blanker, and won't turn off the backlight
1825 when using the X Window system. This also doesn't have anything to
1826 do with your VESA-compliant power-saving monitor. Further, this
1827 option doesn't work for all laptops -- it might not turn off your
1828 backlight at all, or it might print a lot of errors to the console,
1829 especially if you are using gpm.
1831 config APM_ALLOW_INTS
1832 bool "Allow interrupts during APM BIOS calls"
1834 Normally we disable external interrupts while we are making calls to
1835 the APM BIOS as a measure to lessen the effects of a badly behaving
1836 BIOS implementation. The BIOS should reenable interrupts if it
1837 needs to. Unfortunately, some BIOSes do not -- especially those in
1838 many of the newer IBM Thinkpads. If you experience hangs when you
1839 suspend, try setting this to Y. Otherwise, say N.
1843 source "drivers/cpufreq/Kconfig"
1845 source "drivers/cpuidle/Kconfig"
1847 source "drivers/idle/Kconfig"
1852 menu "Bus options (PCI etc.)"
1857 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1859 Find out whether you have a PCI motherboard. PCI is the name of a
1860 bus system, i.e. the way the CPU talks to the other stuff inside
1861 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1862 VESA. If you have PCI, say Y, otherwise N.
1865 prompt "PCI access mode"
1866 depends on X86_32 && PCI
1869 On PCI systems, the BIOS can be used to detect the PCI devices and
1870 determine their configuration. However, some old PCI motherboards
1871 have BIOS bugs and may crash if this is done. Also, some embedded
1872 PCI-based systems don't have any BIOS at all. Linux can also try to
1873 detect the PCI hardware directly without using the BIOS.
1875 With this option, you can specify how Linux should detect the
1876 PCI devices. If you choose "BIOS", the BIOS will be used,
1877 if you choose "Direct", the BIOS won't be used, and if you
1878 choose "MMConfig", then PCI Express MMCONFIG will be used.
1879 If you choose "Any", the kernel will try MMCONFIG, then the
1880 direct access method and falls back to the BIOS if that doesn't
1881 work. If unsure, go with the default, which is "Any".
1886 config PCI_GOMMCONFIG
1903 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1905 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1908 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1912 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1916 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1920 depends on PCI && XEN
1928 bool "Support mmconfig PCI config space access"
1929 depends on X86_64 && PCI && ACPI
1931 config PCI_CNB20LE_QUIRK
1932 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1934 depends on PCI && EXPERIMENTAL
1936 Read the PCI windows out of the CNB20LE host bridge. This allows
1937 PCI hotplug to work on systems with the CNB20LE chipset which do
1940 There's no public spec for this chipset, and this functionality
1941 is known to be incomplete.
1943 You should say N unless you know you need this.
1945 source "drivers/pci/pcie/Kconfig"
1947 source "drivers/pci/Kconfig"
1949 # x86_64 have no ISA slots, but can have ISA-style DMA.
1951 bool "ISA-style DMA support" if (X86_64 && EXPERT)
1954 Enables ISA-style DMA support for devices requiring such controllers.
1962 Find out whether you have ISA slots on your motherboard. ISA is the
1963 name of a bus system, i.e. the way the CPU talks to the other stuff
1964 inside your box. Other bus systems are PCI, EISA, MicroChannel
1965 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1966 newer boards don't support it. If you have ISA, say Y, otherwise N.
1972 The Extended Industry Standard Architecture (EISA) bus was
1973 developed as an open alternative to the IBM MicroChannel bus.
1975 The EISA bus provided some of the features of the IBM MicroChannel
1976 bus while maintaining backward compatibility with cards made for
1977 the older ISA bus. The EISA bus saw limited use between 1988 and
1978 1995 when it was made obsolete by the PCI bus.
1980 Say Y here if you are building a kernel for an EISA-based machine.
1984 source "drivers/eisa/Kconfig"
1989 MicroChannel Architecture is found in some IBM PS/2 machines and
1990 laptops. It is a bus system similar to PCI or ISA. See
1991 <file:Documentation/mca.txt> (and especially the web page given
1992 there) before attempting to build an MCA bus kernel.
1994 source "drivers/mca/Kconfig"
1997 tristate "NatSemi SCx200 support"
1999 This provides basic support for National Semiconductor's
2000 (now AMD's) Geode processors. The driver probes for the
2001 PCI-IDs of several on-chip devices, so its a good dependency
2002 for other scx200_* drivers.
2004 If compiled as a module, the driver is named scx200.
2006 config SCx200HR_TIMER
2007 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2011 This driver provides a clocksource built upon the on-chip
2012 27MHz high-resolution timer. Its also a workaround for
2013 NSC Geode SC-1100's buggy TSC, which loses time when the
2014 processor goes idle (as is done by the scheduler). The
2015 other workaround is idle=poll boot option.
2018 bool "One Laptop Per Child support"
2024 Add support for detecting the unique features of the OLPC
2028 tristate "OLPC XO-1 support"
2029 depends on OLPC && MFD_CS5535
2031 Add support for non-essential features of the OLPC XO-1 laptop.
2037 depends on CPU_SUP_AMD && PCI
2039 source "drivers/pcmcia/Kconfig"
2041 source "drivers/pci/hotplug/Kconfig"
2044 bool "RapidIO support"
2048 If you say Y here, the kernel will include drivers and
2049 infrastructure code to support RapidIO interconnect devices.
2051 source "drivers/rapidio/Kconfig"
2056 menu "Executable file formats / Emulations"
2058 source "fs/Kconfig.binfmt"
2060 config IA32_EMULATION
2061 bool "IA32 Emulation"
2063 select COMPAT_BINFMT_ELF
2065 Include code to run 32-bit programs under a 64-bit kernel. You should
2066 likely turn this on, unless you're 100% sure that you don't have any
2067 32-bit programs left.
2070 tristate "IA32 a.out support"
2071 depends on IA32_EMULATION
2073 Support old a.out binaries in the 32bit emulation.
2077 depends on IA32_EMULATION
2079 config COMPAT_FOR_U64_ALIGNMENT
2083 config SYSVIPC_COMPAT
2085 depends on COMPAT && SYSVIPC
2089 depends on COMPAT && KEYS
2095 config HAVE_ATOMIC_IOMAP
2099 config HAVE_TEXT_POKE_SMP
2101 select STOP_MACHINE if SMP
2103 source "net/Kconfig"
2105 source "drivers/Kconfig"
2107 source "drivers/firmware/Kconfig"
2111 source "arch/x86/Kconfig.debug"
2113 source "security/Kconfig"
2115 source "crypto/Kconfig"
2117 source "arch/x86/kvm/Kconfig"
2119 source "lib/Kconfig"