3 bool "64-bit kernel" if ARCH = "x86"
4 default ARCH = "x86_64"
6 Say yes to build a 64-bit kernel - formerly known as x86_64
7 Say no to build a 32-bit kernel - formerly known as i386
19 select HAVE_AOUT if X86_32
20 select HAVE_UNSTABLE_SCHED_CLOCK
23 select HAVE_PCSPKR_PLATFORM
24 select HAVE_PERF_EVENTS
26 select HAVE_IOREMAP_PROT
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
32 select HAVE_KRETPROBES
34 select HAVE_FTRACE_MCOUNT_RECORD
35 select HAVE_C_RECORDMCOUNT
36 select HAVE_DYNAMIC_FTRACE
37 select HAVE_FUNCTION_TRACER
38 select HAVE_FUNCTION_GRAPH_TRACER
39 select HAVE_FUNCTION_GRAPH_FP_TEST
40 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
41 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
42 select HAVE_SYSCALL_TRACEPOINTS
45 select HAVE_ARCH_TRACEHOOK
46 select HAVE_GENERIC_DMA_COHERENT if X86_32
47 select HAVE_EFFICIENT_UNALIGNED_ACCESS
48 select USER_STACKTRACE_SUPPORT
49 select HAVE_REGS_AND_STACK_ACCESS_API
50 select HAVE_DMA_API_DEBUG
51 select HAVE_KERNEL_GZIP
52 select HAVE_KERNEL_BZIP2
53 select HAVE_KERNEL_LZMA
55 select HAVE_KERNEL_LZO
56 select HAVE_HW_BREAKPOINT
57 select HAVE_MIXED_BREAKPOINTS_REGS
59 select HAVE_PERF_EVENTS_NMI
61 select HAVE_ARCH_KMEMCHECK
62 select HAVE_USER_RETURN_NOTIFIER
63 select HAVE_ARCH_JUMP_LABEL
64 select HAVE_TEXT_POKE_SMP
65 select HAVE_GENERIC_HARDIRQS
66 select HAVE_SPARSE_IRQ
67 select GENERIC_FIND_FIRST_BIT
68 select GENERIC_IRQ_PROBE
69 select GENERIC_PENDING_IRQ if SMP
70 select GENERIC_IRQ_SHOW
71 select IRQ_FORCED_THREADING
72 select USE_GENERIC_SMP_HELPERS if SMP
73 select HAVE_BPF_JIT if (X86_64 && NET)
75 select ARCH_HAVE_NMI_SAFE_CMPXCHG
77 config INSTRUCTION_DECODER
78 def_bool (KPROBES || PERF_EVENTS)
82 default "elf32-i386" if X86_32
83 default "elf64-x86-64" if X86_64
87 default "arch/x86/configs/i386_defconfig" if X86_32
88 default "arch/x86/configs/x86_64_defconfig" if X86_64
90 config GENERIC_CMOS_UPDATE
93 config CLOCKSOURCE_WATCHDOG
96 config GENERIC_CLOCKEVENTS
99 config ARCH_CLOCKSOURCE_DATA
103 config GENERIC_CLOCKEVENTS_BROADCAST
105 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
107 config LOCKDEP_SUPPORT
110 config STACKTRACE_SUPPORT
113 config HAVE_LATENCYTOP_SUPPORT
120 bool "DMA memory allocation support" if EXPERT
123 DMA memory allocation support allows devices with less than 32-bit
124 addressing to allocate within the first 16MB of address space.
125 Disable if no such devices will be used.
132 config NEED_DMA_MAP_STATE
133 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
135 config NEED_SG_DMA_LENGTH
138 config GENERIC_ISA_DMA
147 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
149 config GENERIC_BUG_RELATIVE_POINTERS
152 config GENERIC_HWEIGHT
158 config ARCH_MAY_HAVE_PC_FDC
161 config RWSEM_GENERIC_SPINLOCK
164 config RWSEM_XCHGADD_ALGORITHM
167 config ARCH_HAS_CPU_IDLE_WAIT
170 config GENERIC_CALIBRATE_DELAY
173 config GENERIC_TIME_VSYSCALL
177 config ARCH_HAS_CPU_RELAX
180 config ARCH_HAS_DEFAULT_IDLE
183 config ARCH_HAS_CACHE_LINE_SIZE
186 config HAVE_SETUP_PER_CPU_AREA
189 config NEED_PER_CPU_EMBED_FIRST_CHUNK
192 config NEED_PER_CPU_PAGE_FIRST_CHUNK
195 config HAVE_CPUMASK_OF_CPU_MAP
198 config ARCH_HIBERNATION_POSSIBLE
201 config ARCH_SUSPEND_POSSIBLE
208 config ARCH_POPULATES_NODE_MAP
215 config ARCH_SUPPORTS_OPTIMIZED_INLINING
218 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
221 config HAVE_INTEL_TXT
223 depends on EXPERIMENTAL && DMAR && ACPI
227 depends on X86_32 && SMP
231 depends on X86_64 && SMP
237 config X86_32_LAZY_GS
239 depends on X86_32 && !CC_STACKPROTECTOR
241 config ARCH_HWEIGHT_CFLAGS
243 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
244 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
249 config ARCH_CPU_PROBE_RELEASE
251 depends on HOTPLUG_CPU
253 source "init/Kconfig"
254 source "kernel/Kconfig.freezer"
256 menu "Processor type and features"
258 source "kernel/time/Kconfig"
261 bool "Symmetric multi-processing support"
263 This enables support for systems with more than one CPU. If you have
264 a system with only one CPU, like most personal computers, say N. If
265 you have a system with more than one CPU, say Y.
267 If you say N here, the kernel will run on single and multiprocessor
268 machines, but will use only one CPU of a multiprocessor machine. If
269 you say Y here, the kernel will run on many, but not all,
270 singleprocessor machines. On a singleprocessor machine, the kernel
271 will run faster if you say N here.
273 Note that if you say Y here and choose architecture "586" or
274 "Pentium" under "Processor family", the kernel will not work on 486
275 architectures. Similarly, multiprocessor kernels for the "PPro"
276 architecture may not work on all Pentium based boards.
278 People using multiprocessor machines who say Y here should also say
279 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
280 Management" code will be disabled if you say Y here.
282 See also <file:Documentation/i386/IO-APIC.txt>,
283 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
284 <http://www.tldp.org/docs.html#howto>.
286 If you don't know what to do here, say N.
289 bool "Support x2apic"
290 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
292 This enables x2apic support on CPUs that have this feature.
294 This allows 32-bit apic IDs (so it can support very large systems),
295 and accesses the local apic via MSRs not via mmio.
297 If you don't know what to do here, say N.
300 bool "Enable MPS table" if ACPI
302 depends on X86_LOCAL_APIC
304 For old smp systems that do not have proper acpi support. Newer systems
305 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
308 bool "Support for big SMP systems with more than 8 CPUs"
309 depends on X86_32 && SMP
311 This option is needed for the systems that have more than 8 CPUs
314 config X86_EXTENDED_PLATFORM
315 bool "Support for extended (non-PC) x86 platforms"
318 If you disable this option then the kernel will only support
319 standard PC platforms. (which covers the vast majority of
322 If you enable this option then you'll be able to select support
323 for the following (non-PC) 32 bit x86 platforms:
327 SGI 320/540 (Visual Workstation)
328 Summit/EXA (IBM x440)
329 Unisys ES7000 IA32 series
330 Moorestown MID devices
332 If you have one of these systems, or if you want to build a
333 generic distribution kernel, say Y here - otherwise say N.
337 config X86_EXTENDED_PLATFORM
338 bool "Support for extended (non-PC) x86 platforms"
341 If you disable this option then the kernel will only support
342 standard PC platforms. (which covers the vast majority of
345 If you enable this option then you'll be able to select support
346 for the following (non-PC) 64 bit x86 platforms:
350 If you have one of these systems, or if you want to build a
351 generic distribution kernel, say Y here - otherwise say N.
353 # This is an alphabetically sorted list of 64 bit extended platforms
354 # Please maintain the alphabetic order if and when there are additions
358 select PARAVIRT_GUEST
360 depends on X86_64 && PCI
361 depends on X86_EXTENDED_PLATFORM
363 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
364 supposed to run on these EM64T-based machines. Only choose this option
365 if you have one of these machines.
368 bool "SGI Ultraviolet"
370 depends on X86_EXTENDED_PLATFORM
372 depends on X86_X2APIC
374 This option is needed in order to support SGI Ultraviolet systems.
375 If you don't have one of these, you should say N here.
377 # Following is an alphabetically sorted list of 32 bit extended platforms
378 # Please maintain the alphabetic order if and when there are additions
381 bool "CE4100 TV platform"
383 depends on PCI_GODIRECT
385 depends on X86_EXTENDED_PLATFORM
386 select X86_REBOOTFIXUPS
388 select OF_EARLY_FLATTREE
390 Select for the Intel CE media processor (CE4100) SOC.
391 This option compiles in support for the CE4100 SOC for settop
392 boxes and media devices.
395 bool "Intel MID platform support"
397 depends on X86_EXTENDED_PLATFORM
399 Select to build a kernel capable of supporting Intel MID platform
400 systems which do not have the PCI legacy interfaces (Moorestown,
401 Medfield). If you are building for a PC class system say N here.
406 bool "Moorestown MID platform"
409 depends on X86_IO_APIC
414 select X86_PLATFORM_DEVICES
416 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
417 Internet Device(MID) platform. Moorestown consists of two chips:
418 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
419 Unlike standard x86 PCs, Moorestown does not have many legacy devices
420 nor standard legacy replacement devices/features. e.g. Moorestown does
421 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
426 bool "RDC R-321x SoC"
428 depends on X86_EXTENDED_PLATFORM
430 select X86_REBOOTFIXUPS
432 This option is needed for RDC R-321x system-on-chip, also known
434 If you don't have one of these chips, you should say N here.
436 config X86_32_NON_STANDARD
437 bool "Support non-standard 32-bit SMP architectures"
438 depends on X86_32 && SMP
439 depends on X86_EXTENDED_PLATFORM
441 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
442 subarchitectures. It is intended for a generic binary kernel.
443 if you select them all, kernel will probe it one by one. and will
446 # Alphabetically sorted list of Non standard 32 bit platforms
449 bool "NUMAQ (IBM/Sequent)"
450 depends on X86_32_NON_STANDARD
455 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
456 NUMA multiquad box. This changes the way that processors are
457 bootstrapped, and uses Clustered Logical APIC addressing mode instead
458 of Flat Logical. You will need a new lynxer.elf file to flash your
459 firmware with - send email to <Martin.Bligh@us.ibm.com>.
461 config X86_SUPPORTS_MEMORY_FAILURE
463 # MCE code calls memory_failure():
465 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
466 depends on !X86_NUMAQ
467 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
468 depends on X86_64 || !SPARSEMEM
469 select ARCH_SUPPORTS_MEMORY_FAILURE
472 bool "SGI 320/540 (Visual Workstation)"
473 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
474 depends on X86_32_NON_STANDARD
476 The SGI Visual Workstation series is an IA32-based workstation
477 based on SGI systems chips with some legacy PC hardware attached.
479 Say Y here to create a kernel to run on the SGI 320 or 540.
481 A kernel compiled for the Visual Workstation will run on general
482 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
485 bool "Summit/EXA (IBM x440)"
486 depends on X86_32_NON_STANDARD
488 This option is needed for IBM systems that use the Summit/EXA chipset.
489 In particular, it is needed for the x440.
492 bool "Unisys ES7000 IA32 series"
493 depends on X86_32_NON_STANDARD && X86_BIGSMP
495 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
496 supposed to run on an IA32-based Unisys ES7000 system.
499 tristate "Eurobraille/Iris poweroff module"
502 The Iris machines from EuroBraille do not have APM or ACPI support
503 to shut themselves down properly. A special I/O sequence is
504 needed to do so, which is what this module does at
507 This is only for Iris machines from EuroBraille.
511 config SCHED_OMIT_FRAME_POINTER
513 prompt "Single-depth WCHAN output"
516 Calculate simpler /proc/<PID>/wchan values. If this option
517 is disabled then wchan values will recurse back to the
518 caller function. This provides more accurate wchan values,
519 at the expense of slightly more scheduling overhead.
521 If in doubt, say "Y".
523 menuconfig PARAVIRT_GUEST
524 bool "Paravirtualized guest support"
526 Say Y here to get to see options related to running Linux under
527 various hypervisors. This option alone does not add any kernel code.
529 If you say N, all options in this submenu will be skipped and disabled.
533 config PARAVIRT_TIME_ACCOUNTING
534 bool "Paravirtual steal time accounting"
538 Select this option to enable fine granularity task steal time
539 accounting. Time spent executing other tasks in parallel with
540 the current vCPU is discounted from the vCPU power. To account for
541 that, there can be a small performance impact.
543 If in doubt, say N here.
545 source "arch/x86/xen/Kconfig"
548 bool "KVM paravirtualized clock"
550 select PARAVIRT_CLOCK
552 Turning on this option will allow you to run a paravirtualized clock
553 when running over the KVM hypervisor. Instead of relying on a PIT
554 (or probably other) emulation by the underlying device model, the host
555 provides the guest with timing infrastructure such as time of day, and
559 bool "KVM Guest support"
562 This option enables various optimizations for running under the KVM
565 source "arch/x86/lguest/Kconfig"
568 bool "Enable paravirtualization code"
570 This changes the kernel so it can modify itself when it is run
571 under a hypervisor, potentially improving performance significantly
572 over full virtualization. However, when run without a hypervisor
573 the kernel is theoretically slower and slightly larger.
575 config PARAVIRT_SPINLOCKS
576 bool "Paravirtualization layer for spinlocks"
577 depends on PARAVIRT && SMP && EXPERIMENTAL
579 Paravirtualized spinlocks allow a pvops backend to replace the
580 spinlock implementation with something virtualization-friendly
581 (for example, block the virtual CPU rather than spinning).
583 Unfortunately the downside is an up to 5% performance hit on
584 native kernels, with various workloads.
586 If you are unsure how to answer this question, answer N.
588 config PARAVIRT_CLOCK
593 config PARAVIRT_DEBUG
594 bool "paravirt-ops debugging"
595 depends on PARAVIRT && DEBUG_KERNEL
597 Enable to debug paravirt_ops internals. Specifically, BUG if
598 a paravirt_op is missing when it is called.
606 This option adds a kernel parameter 'memtest', which allows memtest
608 memtest=0, mean disabled; -- default
609 memtest=1, mean do 1 test pattern;
611 memtest=4, mean do 4 test patterns.
612 If you are unsure how to answer this question, answer N.
614 config X86_SUMMIT_NUMA
616 depends on X86_32 && NUMA && X86_32_NON_STANDARD
618 config X86_CYCLONE_TIMER
620 depends on X86_32_NON_STANDARD
622 source "arch/x86/Kconfig.cpu"
626 prompt "HPET Timer Support" if X86_32
628 Use the IA-PC HPET (High Precision Event Timer) to manage
629 time in preference to the PIT and RTC, if a HPET is
631 HPET is the next generation timer replacing legacy 8254s.
632 The HPET provides a stable time base on SMP
633 systems, unlike the TSC, but it is more expensive to access,
634 as it is off-chip. You can find the HPET spec at
635 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
637 You can safely choose Y here. However, HPET will only be
638 activated if the platform and the BIOS support this feature.
639 Otherwise the 8254 will be used for timing services.
641 Choose N to continue using the legacy 8254 timer.
643 config HPET_EMULATE_RTC
645 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
649 prompt "Langwell APB Timer Support" if X86_MRST
652 APB timer is the replacement for 8254, HPET on X86 MID platforms.
653 The APBT provides a stable time base on SMP
654 systems, unlike the TSC, but it is more expensive to access,
655 as it is off-chip. APB timers are always running regardless of CPU
656 C states, they are used as per CPU clockevent device when possible.
658 # Mark as expert because too many people got it wrong.
659 # The code disables itself when not needed.
662 bool "Enable DMI scanning" if EXPERT
664 Enabled scanning of DMI to identify machine quirks. Say Y
665 here unless you have verified that your setup is not
666 affected by entries in the DMI blacklist. Required by PNP
670 bool "GART IOMMU support" if EXPERT
673 depends on X86_64 && PCI && AMD_NB
675 Support for full DMA access of devices with 32bit memory access only
676 on systems with more than 3GB. This is usually needed for USB,
677 sound, many IDE/SATA chipsets and some other devices.
678 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
679 based hardware IOMMU and a software bounce buffer based IOMMU used
680 on Intel systems and as fallback.
681 The code is only active when needed (enough memory and limited
682 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
686 bool "IBM Calgary IOMMU support"
688 depends on X86_64 && PCI && EXPERIMENTAL
690 Support for hardware IOMMUs in IBM's xSeries x366 and x460
691 systems. Needed to run systems with more than 3GB of memory
692 properly with 32-bit PCI devices that do not support DAC
693 (Double Address Cycle). Calgary also supports bus level
694 isolation, where all DMAs pass through the IOMMU. This
695 prevents them from going anywhere except their intended
696 destination. This catches hard-to-find kernel bugs and
697 mis-behaving drivers and devices that do not use the DMA-API
698 properly to set up their DMA buffers. The IOMMU can be
699 turned off at boot time with the iommu=off parameter.
700 Normally the kernel will make the right choice by itself.
703 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
705 prompt "Should Calgary be enabled by default?"
706 depends on CALGARY_IOMMU
708 Should Calgary be enabled by default? if you choose 'y', Calgary
709 will be used (if it exists). If you choose 'n', Calgary will not be
710 used even if it exists. If you choose 'n' and would like to use
711 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
714 # need this always selected by IOMMU for the VIA workaround
718 Support for software bounce buffers used on x86-64 systems
719 which don't have a hardware IOMMU (e.g. the current generation
720 of Intel's x86-64 CPUs). Using this PCI devices which can only
721 access 32-bits of memory can be used on systems with more than
722 3 GB of memory. If unsure, say Y.
725 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
728 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
729 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
730 select CPUMASK_OFFSTACK
732 Enable maximum number of CPUS and NUMA Nodes for this architecture.
736 int "Maximum number of CPUs" if SMP && !MAXSMP
737 range 2 8 if SMP && X86_32 && !X86_BIGSMP
738 range 2 512 if SMP && !MAXSMP
740 default "4096" if MAXSMP
741 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
744 This allows you to specify the maximum number of CPUs which this
745 kernel will support. The maximum supported value is 512 and the
746 minimum value which makes sense is 2.
748 This is purely to save memory - each supported CPU adds
749 approximately eight kilobytes to the kernel image.
752 bool "SMT (Hyperthreading) scheduler support"
755 SMT scheduler support improves the CPU scheduler's decision making
756 when dealing with Intel Pentium 4 chips with HyperThreading at a
757 cost of slightly increased overhead in some places. If unsure say
762 prompt "Multi-core scheduler support"
765 Multi-core scheduler support improves the CPU scheduler's decision
766 making when dealing with multi-core CPU chips at a cost of slightly
767 increased overhead in some places. If unsure say N here.
769 config IRQ_TIME_ACCOUNTING
770 bool "Fine granularity task level IRQ time accounting"
773 Select this option to enable fine granularity task irq time
774 accounting. This is done by reading a timestamp on each
775 transitions between softirq and hardirq state, so there can be a
776 small performance impact.
778 If in doubt, say N here.
780 source "kernel/Kconfig.preempt"
783 bool "Local APIC support on uniprocessors"
784 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
786 A local APIC (Advanced Programmable Interrupt Controller) is an
787 integrated interrupt controller in the CPU. If you have a single-CPU
788 system which has a processor with a local APIC, you can say Y here to
789 enable and use it. If you say Y here even though your machine doesn't
790 have a local APIC, then the kernel will still run with no slowdown at
791 all. The local APIC supports CPU-generated self-interrupts (timer,
792 performance counters), and the NMI watchdog which detects hard
796 bool "IO-APIC support on uniprocessors"
797 depends on X86_UP_APIC
799 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
800 SMP-capable replacement for PC-style interrupt controllers. Most
801 SMP systems and many recent uniprocessor systems have one.
803 If you have a single-CPU system with an IO-APIC, you can say Y here
804 to use it. If you say Y here even though your machine doesn't have
805 an IO-APIC, then the kernel will still run with no slowdown at all.
807 config X86_LOCAL_APIC
809 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
813 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
815 config X86_VISWS_APIC
817 depends on X86_32 && X86_VISWS
819 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
820 bool "Reroute for broken boot IRQs"
821 depends on X86_IO_APIC
823 This option enables a workaround that fixes a source of
824 spurious interrupts. This is recommended when threaded
825 interrupt handling is used on systems where the generation of
826 superfluous "boot interrupts" cannot be disabled.
828 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
829 entry in the chipset's IO-APIC is masked (as, e.g. the RT
830 kernel does during interrupt handling). On chipsets where this
831 boot IRQ generation cannot be disabled, this workaround keeps
832 the original IRQ line masked so that only the equivalent "boot
833 IRQ" is delivered to the CPUs. The workaround also tells the
834 kernel to set up the IRQ handler on the boot IRQ line. In this
835 way only one interrupt is delivered to the kernel. Otherwise
836 the spurious second interrupt may cause the kernel to bring
837 down (vital) interrupt lines.
839 Only affects "broken" chipsets. Interrupt sharing may be
840 increased on these systems.
843 bool "Machine Check / overheating reporting"
845 Machine Check support allows the processor to notify the
846 kernel if it detects a problem (e.g. overheating, data corruption).
847 The action the kernel takes depends on the severity of the problem,
848 ranging from warning messages to halting the machine.
852 prompt "Intel MCE features"
853 depends on X86_MCE && X86_LOCAL_APIC
855 Additional support for intel specific MCE features such as
860 prompt "AMD MCE features"
861 depends on X86_MCE && X86_LOCAL_APIC
863 Additional support for AMD specific MCE features such as
864 the DRAM Error Threshold.
866 config X86_ANCIENT_MCE
867 bool "Support for old Pentium 5 / WinChip machine checks"
868 depends on X86_32 && X86_MCE
870 Include support for machine check handling on old Pentium 5 or WinChip
871 systems. These typically need to be enabled explicitely on the command
874 config X86_MCE_THRESHOLD
875 depends on X86_MCE_AMD || X86_MCE_INTEL
878 config X86_MCE_INJECT
880 tristate "Machine check injector support"
882 Provide support for injecting machine checks for testing purposes.
883 If you don't know what a machine check is and you don't do kernel
884 QA it is safe to say n.
886 config X86_THERMAL_VECTOR
888 depends on X86_MCE_INTEL
891 bool "Enable VM86 support" if EXPERT
895 This option is required by programs like DOSEMU to run 16-bit legacy
896 code on X86 processors. It also may be needed by software like
897 XFree86 to initialize some video cards via BIOS. Disabling this
898 option saves about 6k.
901 tristate "Toshiba Laptop support"
904 This adds a driver to safely access the System Management Mode of
905 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
906 not work on models with a Phoenix BIOS. The System Management Mode
907 is used to set the BIOS and power saving options on Toshiba portables.
909 For information on utilities to make use of this driver see the
910 Toshiba Linux utilities web site at:
911 <http://www.buzzard.org.uk/toshiba/>.
913 Say Y if you intend to run this kernel on a Toshiba portable.
917 tristate "Dell laptop support"
920 This adds a driver to safely access the System Management Mode
921 of the CPU on the Dell Inspiron 8000. The System Management Mode
922 is used to read cpu temperature and cooling fan status and to
923 control the fans on the I8K portables.
925 This driver has been tested only on the Inspiron 8000 but it may
926 also work with other Dell laptops. You can force loading on other
927 models by passing the parameter `force=1' to the module. Use at
930 For information on utilities to make use of this driver see the
931 I8K Linux utilities web site at:
932 <http://people.debian.org/~dz/i8k/>
934 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
937 config X86_REBOOTFIXUPS
938 bool "Enable X86 board specific fixups for reboot"
941 This enables chipset and/or board specific fixups to be done
942 in order to get reboot to work correctly. This is only needed on
943 some combinations of hardware and BIOS. The symptom, for which
944 this config is intended, is when reboot ends with a stalled/hung
947 Currently, the only fixup is for the Geode machines using
948 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
950 Say Y if you want to enable the fixup. Currently, it's safe to
951 enable this option even if you don't need it.
955 tristate "/dev/cpu/microcode - microcode support"
958 If you say Y here, you will be able to update the microcode on
959 certain Intel and AMD processors. The Intel support is for the
960 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
961 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
962 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
963 You will obviously need the actual microcode binary data itself
964 which is not shipped with the Linux kernel.
966 This option selects the general module only, you need to select
967 at least one vendor specific module as well.
969 To compile this driver as a module, choose M here: the
970 module will be called microcode.
972 config MICROCODE_INTEL
973 bool "Intel microcode patch loading support"
978 This options enables microcode patch loading support for Intel
981 For latest news and information on obtaining all the required
982 Intel ingredients for this driver, check:
983 <http://www.urbanmyth.org/microcode/>.
986 bool "AMD microcode patch loading support"
990 If you select this option, microcode patch loading support for AMD
991 processors will be enabled.
993 config MICROCODE_OLD_INTERFACE
998 tristate "/dev/cpu/*/msr - Model-specific register support"
1000 This device gives privileged processes access to the x86
1001 Model-Specific Registers (MSRs). It is a character device with
1002 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1003 MSR accesses are directed to a specific CPU on multi-processor
1007 tristate "/dev/cpu/*/cpuid - CPU information support"
1009 This device gives processes access to the x86 CPUID instruction to
1010 be executed on a specific processor. It is a character device
1011 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1015 prompt "High Memory Support"
1016 default HIGHMEM64G if X86_NUMAQ
1022 depends on !X86_NUMAQ
1024 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1025 However, the address space of 32-bit x86 processors is only 4
1026 Gigabytes large. That means that, if you have a large amount of
1027 physical memory, not all of it can be "permanently mapped" by the
1028 kernel. The physical memory that's not permanently mapped is called
1031 If you are compiling a kernel which will never run on a machine with
1032 more than 1 Gigabyte total physical RAM, answer "off" here (default
1033 choice and suitable for most users). This will result in a "3GB/1GB"
1034 split: 3GB are mapped so that each process sees a 3GB virtual memory
1035 space and the remaining part of the 4GB virtual memory space is used
1036 by the kernel to permanently map as much physical memory as
1039 If the machine has between 1 and 4 Gigabytes physical RAM, then
1042 If more than 4 Gigabytes is used then answer "64GB" here. This
1043 selection turns Intel PAE (Physical Address Extension) mode on.
1044 PAE implements 3-level paging on IA32 processors. PAE is fully
1045 supported by Linux, PAE mode is implemented on all recent Intel
1046 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1047 then the kernel will not boot on CPUs that don't support PAE!
1049 The actual amount of total physical memory will either be
1050 auto detected or can be forced by using a kernel command line option
1051 such as "mem=256M". (Try "man bootparam" or see the documentation of
1052 your boot loader (lilo or loadlin) about how to pass options to the
1053 kernel at boot time.)
1055 If unsure, say "off".
1059 depends on !X86_NUMAQ
1061 Select this if you have a 32-bit processor and between 1 and 4
1062 gigabytes of physical RAM.
1066 depends on !M386 && !M486
1069 Select this if you have a 32-bit processor and more than 4
1070 gigabytes of physical RAM.
1075 depends on EXPERIMENTAL
1076 prompt "Memory split" if EXPERT
1080 Select the desired split between kernel and user memory.
1082 If the address range available to the kernel is less than the
1083 physical memory installed, the remaining memory will be available
1084 as "high memory". Accessing high memory is a little more costly
1085 than low memory, as it needs to be mapped into the kernel first.
1086 Note that increasing the kernel address space limits the range
1087 available to user programs, making the address space there
1088 tighter. Selecting anything other than the default 3G/1G split
1089 will also likely make your kernel incompatible with binary-only
1092 If you are not absolutely sure what you are doing, leave this
1096 bool "3G/1G user/kernel split"
1097 config VMSPLIT_3G_OPT
1099 bool "3G/1G user/kernel split (for full 1G low memory)"
1101 bool "2G/2G user/kernel split"
1102 config VMSPLIT_2G_OPT
1104 bool "2G/2G user/kernel split (for full 2G low memory)"
1106 bool "1G/3G user/kernel split"
1111 default 0xB0000000 if VMSPLIT_3G_OPT
1112 default 0x80000000 if VMSPLIT_2G
1113 default 0x78000000 if VMSPLIT_2G_OPT
1114 default 0x40000000 if VMSPLIT_1G
1120 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1123 bool "PAE (Physical Address Extension) Support"
1124 depends on X86_32 && !HIGHMEM4G
1126 PAE is required for NX support, and furthermore enables
1127 larger swapspace support for non-overcommit purposes. It
1128 has the cost of more pagetable lookup overhead, and also
1129 consumes more pagetable space per process.
1131 config ARCH_PHYS_ADDR_T_64BIT
1132 def_bool X86_64 || X86_PAE
1134 config ARCH_DMA_ADDR_T_64BIT
1135 def_bool X86_64 || HIGHMEM64G
1137 config DIRECT_GBPAGES
1138 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1142 Allow the kernel linear mapping to use 1GB pages on CPUs that
1143 support it. This can improve the kernel's performance a tiny bit by
1144 reducing TLB pressure. If in doubt, say "Y".
1146 # Common NUMA Features
1148 bool "Numa Memory Allocation and Scheduler Support"
1150 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1151 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1153 Enable NUMA (Non Uniform Memory Access) support.
1155 The kernel will try to allocate memory used by a CPU on the
1156 local memory controller of the CPU and add some more
1157 NUMA awareness to the kernel.
1159 For 64-bit this is recommended if the system is Intel Core i7
1160 (or later), AMD Opteron, or EM64T NUMA.
1162 For 32-bit this is only needed on (rare) 32-bit-only platforms
1163 that support NUMA topologies, such as NUMAQ / Summit, or if you
1164 boot a 32-bit kernel on a 64-bit NUMA platform.
1166 Otherwise, you should say N.
1168 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1169 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1173 prompt "Old style AMD Opteron NUMA detection"
1174 depends on X86_64 && NUMA && PCI
1176 Enable AMD NUMA node topology detection. You should say Y here if
1177 you have a multi processor AMD system. This uses an old method to
1178 read the NUMA configuration directly from the builtin Northbridge
1179 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1180 which also takes priority if both are compiled in.
1182 config X86_64_ACPI_NUMA
1184 prompt "ACPI NUMA detection"
1185 depends on X86_64 && NUMA && ACPI && PCI
1188 Enable ACPI SRAT based node topology detection.
1190 # Some NUMA nodes have memory ranges that span
1191 # other nodes. Even though a pfn is valid and
1192 # between a node's start and end pfns, it may not
1193 # reside on that node. See memmap_init_zone()
1195 config NODES_SPAN_OTHER_NODES
1197 depends on X86_64_ACPI_NUMA
1200 bool "NUMA emulation"
1203 Enable NUMA emulation. A flat machine will be split
1204 into virtual nodes when booted with "numa=fake=N", where N is the
1205 number of nodes. This is only useful for debugging.
1208 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1210 default "10" if MAXSMP
1211 default "6" if X86_64
1212 default "4" if X86_NUMAQ
1214 depends on NEED_MULTIPLE_NODES
1216 Specify the maximum number of NUMA Nodes available on the target
1217 system. Increases memory reserved to accommodate various tables.
1219 config HAVE_ARCH_BOOTMEM
1221 depends on X86_32 && NUMA
1223 config HAVE_ARCH_ALLOC_REMAP
1225 depends on X86_32 && NUMA
1227 config ARCH_HAVE_MEMORY_PRESENT
1229 depends on X86_32 && DISCONTIGMEM
1231 config NEED_NODE_MEMMAP_SIZE
1233 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1235 config ARCH_FLATMEM_ENABLE
1237 depends on X86_32 && !NUMA
1239 config ARCH_DISCONTIGMEM_ENABLE
1241 depends on NUMA && X86_32
1243 config ARCH_DISCONTIGMEM_DEFAULT
1245 depends on NUMA && X86_32
1247 config ARCH_SPARSEMEM_ENABLE
1249 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1250 select SPARSEMEM_STATIC if X86_32
1251 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1253 config ARCH_SPARSEMEM_DEFAULT
1257 config ARCH_SELECT_MEMORY_MODEL
1259 depends on ARCH_SPARSEMEM_ENABLE
1261 config ARCH_MEMORY_PROBE
1263 depends on MEMORY_HOTPLUG
1265 config ARCH_PROC_KCORE_TEXT
1267 depends on X86_64 && PROC_KCORE
1269 config ILLEGAL_POINTER_VALUE
1272 default 0xdead000000000000 if X86_64
1277 bool "Allocate 3rd-level pagetables from highmem"
1280 The VM uses one page table entry for each page of physical memory.
1281 For systems with a lot of RAM, this can be wasteful of precious
1282 low memory. Setting this option will put user-space page table
1283 entries in high memory.
1285 config X86_CHECK_BIOS_CORRUPTION
1286 bool "Check for low memory corruption"
1288 Periodically check for memory corruption in low memory, which
1289 is suspected to be caused by BIOS. Even when enabled in the
1290 configuration, it is disabled at runtime. Enable it by
1291 setting "memory_corruption_check=1" on the kernel command
1292 line. By default it scans the low 64k of memory every 60
1293 seconds; see the memory_corruption_check_size and
1294 memory_corruption_check_period parameters in
1295 Documentation/kernel-parameters.txt to adjust this.
1297 When enabled with the default parameters, this option has
1298 almost no overhead, as it reserves a relatively small amount
1299 of memory and scans it infrequently. It both detects corruption
1300 and prevents it from affecting the running system.
1302 It is, however, intended as a diagnostic tool; if repeatable
1303 BIOS-originated corruption always affects the same memory,
1304 you can use memmap= to prevent the kernel from using that
1307 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1308 bool "Set the default setting of memory_corruption_check"
1309 depends on X86_CHECK_BIOS_CORRUPTION
1312 Set whether the default state of memory_corruption_check is
1315 config X86_RESERVE_LOW
1316 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1320 Specify the amount of low memory to reserve for the BIOS.
1322 The first page contains BIOS data structures that the kernel
1323 must not use, so that page must always be reserved.
1325 By default we reserve the first 64K of physical RAM, as a
1326 number of BIOSes are known to corrupt that memory range
1327 during events such as suspend/resume or monitor cable
1328 insertion, so it must not be used by the kernel.
1330 You can set this to 4 if you are absolutely sure that you
1331 trust the BIOS to get all its memory reservations and usages
1332 right. If you know your BIOS have problems beyond the
1333 default 64K area, you can set this to 640 to avoid using the
1334 entire low memory range.
1336 If you have doubts about the BIOS (e.g. suspend/resume does
1337 not work or there's kernel crashes after certain hardware
1338 hotplug events) then you might want to enable
1339 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1340 typical corruption patterns.
1342 Leave this to the default value of 64 if you are unsure.
1344 config MATH_EMULATION
1346 prompt "Math emulation" if X86_32
1348 Linux can emulate a math coprocessor (used for floating point
1349 operations) if you don't have one. 486DX and Pentium processors have
1350 a math coprocessor built in, 486SX and 386 do not, unless you added
1351 a 487DX or 387, respectively. (The messages during boot time can
1352 give you some hints here ["man dmesg"].) Everyone needs either a
1353 coprocessor or this emulation.
1355 If you don't have a math coprocessor, you need to say Y here; if you
1356 say Y here even though you have a coprocessor, the coprocessor will
1357 be used nevertheless. (This behavior can be changed with the kernel
1358 command line option "no387", which comes handy if your coprocessor
1359 is broken. Try "man bootparam" or see the documentation of your boot
1360 loader (lilo or loadlin) about how to pass options to the kernel at
1361 boot time.) This means that it is a good idea to say Y here if you
1362 intend to use this kernel on different machines.
1364 More information about the internals of the Linux math coprocessor
1365 emulation can be found in <file:arch/x86/math-emu/README>.
1367 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1368 kernel, it won't hurt.
1372 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1374 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1375 the Memory Type Range Registers (MTRRs) may be used to control
1376 processor access to memory ranges. This is most useful if you have
1377 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1378 allows bus write transfers to be combined into a larger transfer
1379 before bursting over the PCI/AGP bus. This can increase performance
1380 of image write operations 2.5 times or more. Saying Y here creates a
1381 /proc/mtrr file which may be used to manipulate your processor's
1382 MTRRs. Typically the X server should use this.
1384 This code has a reasonably generic interface so that similar
1385 control registers on other processors can be easily supported
1388 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1389 Registers (ARRs) which provide a similar functionality to MTRRs. For
1390 these, the ARRs are used to emulate the MTRRs.
1391 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1392 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1393 write-combining. All of these processors are supported by this code
1394 and it makes sense to say Y here if you have one of them.
1396 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1397 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1398 can lead to all sorts of problems, so it's good to say Y here.
1400 You can safely say Y even if your machine doesn't have MTRRs, you'll
1401 just add about 9 KB to your kernel.
1403 See <file:Documentation/x86/mtrr.txt> for more information.
1405 config MTRR_SANITIZER
1407 prompt "MTRR cleanup support"
1410 Convert MTRR layout from continuous to discrete, so X drivers can
1411 add writeback entries.
1413 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1414 The largest mtrr entry size for a continuous block can be set with
1419 config MTRR_SANITIZER_ENABLE_DEFAULT
1420 int "MTRR cleanup enable value (0-1)"
1423 depends on MTRR_SANITIZER
1425 Enable mtrr cleanup default value
1427 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1428 int "MTRR cleanup spare reg num (0-7)"
1431 depends on MTRR_SANITIZER
1433 mtrr cleanup spare entries default, it can be changed via
1434 mtrr_spare_reg_nr=N on the kernel command line.
1438 prompt "x86 PAT support" if EXPERT
1441 Use PAT attributes to setup page level cache control.
1443 PATs are the modern equivalents of MTRRs and are much more
1444 flexible than MTRRs.
1446 Say N here if you see bootup problems (boot crash, boot hang,
1447 spontaneous reboots) or a non-working video driver.
1451 config ARCH_USES_PG_UNCACHED
1456 bool "EFI runtime service support"
1459 This enables the kernel to use EFI runtime services that are
1460 available (such as the EFI variable services).
1462 This option is only useful on systems that have EFI firmware.
1463 In addition, you should use the latest ELILO loader available
1464 at <http://elilo.sourceforge.net> in order to take advantage
1465 of EFI runtime services. However, even with this option, the
1466 resultant kernel should continue to boot on existing non-EFI
1471 prompt "Enable seccomp to safely compute untrusted bytecode"
1473 This kernel feature is useful for number crunching applications
1474 that may need to compute untrusted bytecode during their
1475 execution. By using pipes or other transports made available to
1476 the process as file descriptors supporting the read/write
1477 syscalls, it's possible to isolate those applications in
1478 their own address space using seccomp. Once seccomp is
1479 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1480 and the task is only allowed to execute a few safe syscalls
1481 defined by each seccomp mode.
1483 If unsure, say Y. Only embedded should say N here.
1485 config CC_STACKPROTECTOR
1486 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1488 This option turns on the -fstack-protector GCC feature. This
1489 feature puts, at the beginning of functions, a canary value on
1490 the stack just before the return address, and validates
1491 the value just before actually returning. Stack based buffer
1492 overflows (that need to overwrite this return address) now also
1493 overwrite the canary, which gets detected and the attack is then
1494 neutralized via a kernel panic.
1496 This feature requires gcc version 4.2 or above, or a distribution
1497 gcc with the feature backported. Older versions are automatically
1498 detected and for those versions, this configuration option is
1499 ignored. (and a warning is printed during bootup)
1501 source kernel/Kconfig.hz
1504 bool "kexec system call"
1506 kexec is a system call that implements the ability to shutdown your
1507 current kernel, and to start another kernel. It is like a reboot
1508 but it is independent of the system firmware. And like a reboot
1509 you can start any kernel with it, not just Linux.
1511 The name comes from the similarity to the exec system call.
1513 It is an ongoing process to be certain the hardware in a machine
1514 is properly shutdown, so do not be surprised if this code does not
1515 initially work for you. It may help to enable device hotplugging
1516 support. As of this writing the exact hardware interface is
1517 strongly in flux, so no good recommendation can be made.
1520 bool "kernel crash dumps"
1521 depends on X86_64 || (X86_32 && HIGHMEM)
1523 Generate crash dump after being started by kexec.
1524 This should be normally only set in special crash dump kernels
1525 which are loaded in the main kernel with kexec-tools into
1526 a specially reserved region and then later executed after
1527 a crash by kdump/kexec. The crash dump kernel must be compiled
1528 to a memory address not used by the main kernel or BIOS using
1529 PHYSICAL_START, or it must be built as a relocatable image
1530 (CONFIG_RELOCATABLE=y).
1531 For more details see Documentation/kdump/kdump.txt
1534 bool "kexec jump (EXPERIMENTAL)"
1535 depends on EXPERIMENTAL
1536 depends on KEXEC && HIBERNATION
1538 Jump between original kernel and kexeced kernel and invoke
1539 code in physical address mode via KEXEC
1541 config PHYSICAL_START
1542 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1545 This gives the physical address where the kernel is loaded.
1547 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1548 bzImage will decompress itself to above physical address and
1549 run from there. Otherwise, bzImage will run from the address where
1550 it has been loaded by the boot loader and will ignore above physical
1553 In normal kdump cases one does not have to set/change this option
1554 as now bzImage can be compiled as a completely relocatable image
1555 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1556 address. This option is mainly useful for the folks who don't want
1557 to use a bzImage for capturing the crash dump and want to use a
1558 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1559 to be specifically compiled to run from a specific memory area
1560 (normally a reserved region) and this option comes handy.
1562 So if you are using bzImage for capturing the crash dump,
1563 leave the value here unchanged to 0x1000000 and set
1564 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1565 for capturing the crash dump change this value to start of
1566 the reserved region. In other words, it can be set based on
1567 the "X" value as specified in the "crashkernel=YM@XM"
1568 command line boot parameter passed to the panic-ed
1569 kernel. Please take a look at Documentation/kdump/kdump.txt
1570 for more details about crash dumps.
1572 Usage of bzImage for capturing the crash dump is recommended as
1573 one does not have to build two kernels. Same kernel can be used
1574 as production kernel and capture kernel. Above option should have
1575 gone away after relocatable bzImage support is introduced. But it
1576 is present because there are users out there who continue to use
1577 vmlinux for dump capture. This option should go away down the
1580 Don't change this unless you know what you are doing.
1583 bool "Build a relocatable kernel"
1586 This builds a kernel image that retains relocation information
1587 so it can be loaded someplace besides the default 1MB.
1588 The relocations tend to make the kernel binary about 10% larger,
1589 but are discarded at runtime.
1591 One use is for the kexec on panic case where the recovery kernel
1592 must live at a different physical address than the primary
1595 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1596 it has been loaded at and the compile time physical address
1597 (CONFIG_PHYSICAL_START) is ignored.
1599 # Relocation on x86-32 needs some additional build support
1600 config X86_NEED_RELOCS
1602 depends on X86_32 && RELOCATABLE
1604 config PHYSICAL_ALIGN
1605 hex "Alignment value to which kernel should be aligned" if X86_32
1607 range 0x2000 0x1000000
1609 This value puts the alignment restrictions on physical address
1610 where kernel is loaded and run from. Kernel is compiled for an
1611 address which meets above alignment restriction.
1613 If bootloader loads the kernel at a non-aligned address and
1614 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1615 address aligned to above value and run from there.
1617 If bootloader loads the kernel at a non-aligned address and
1618 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1619 load address and decompress itself to the address it has been
1620 compiled for and run from there. The address for which kernel is
1621 compiled already meets above alignment restrictions. Hence the
1622 end result is that kernel runs from a physical address meeting
1623 above alignment restrictions.
1625 Don't change this unless you know what you are doing.
1628 bool "Support for hot-pluggable CPUs"
1629 depends on SMP && HOTPLUG
1631 Say Y here to allow turning CPUs off and on. CPUs can be
1632 controlled through /sys/devices/system/cpu.
1633 ( Note: power management support will enable this option
1634 automatically on SMP systems. )
1635 Say N if you want to disable CPU hotplug.
1639 prompt "Compat VDSO support"
1640 depends on X86_32 || IA32_EMULATION
1642 Map the 32-bit VDSO to the predictable old-style address too.
1644 Say N here if you are running a sufficiently recent glibc
1645 version (2.3.3 or later), to remove the high-mapped
1646 VDSO mapping and to exclusively use the randomized VDSO.
1651 bool "Built-in kernel command line"
1653 Allow for specifying boot arguments to the kernel at
1654 build time. On some systems (e.g. embedded ones), it is
1655 necessary or convenient to provide some or all of the
1656 kernel boot arguments with the kernel itself (that is,
1657 to not rely on the boot loader to provide them.)
1659 To compile command line arguments into the kernel,
1660 set this option to 'Y', then fill in the
1661 the boot arguments in CONFIG_CMDLINE.
1663 Systems with fully functional boot loaders (i.e. non-embedded)
1664 should leave this option set to 'N'.
1667 string "Built-in kernel command string"
1668 depends on CMDLINE_BOOL
1671 Enter arguments here that should be compiled into the kernel
1672 image and used at boot time. If the boot loader provides a
1673 command line at boot time, it is appended to this string to
1674 form the full kernel command line, when the system boots.
1676 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1677 change this behavior.
1679 In most cases, the command line (whether built-in or provided
1680 by the boot loader) should specify the device for the root
1683 config CMDLINE_OVERRIDE
1684 bool "Built-in command line overrides boot loader arguments"
1685 depends on CMDLINE_BOOL
1687 Set this option to 'Y' to have the kernel ignore the boot loader
1688 command line, and use ONLY the built-in command line.
1690 This is used to work around broken boot loaders. This should
1691 be set to 'N' under normal conditions.
1695 config ARCH_ENABLE_MEMORY_HOTPLUG
1697 depends on X86_64 || (X86_32 && HIGHMEM)
1699 config ARCH_ENABLE_MEMORY_HOTREMOVE
1701 depends on MEMORY_HOTPLUG
1703 config USE_PERCPU_NUMA_NODE_ID
1707 menu "Power management and ACPI options"
1709 config ARCH_HIBERNATION_HEADER
1711 depends on X86_64 && HIBERNATION
1713 source "kernel/power/Kconfig"
1715 source "drivers/acpi/Kconfig"
1717 source "drivers/sfi/Kconfig"
1721 depends on APM || APM_MODULE
1724 tristate "APM (Advanced Power Management) BIOS support"
1725 depends on X86_32 && PM_SLEEP
1727 APM is a BIOS specification for saving power using several different
1728 techniques. This is mostly useful for battery powered laptops with
1729 APM compliant BIOSes. If you say Y here, the system time will be
1730 reset after a RESUME operation, the /proc/apm device will provide
1731 battery status information, and user-space programs will receive
1732 notification of APM "events" (e.g. battery status change).
1734 If you select "Y" here, you can disable actual use of the APM
1735 BIOS by passing the "apm=off" option to the kernel at boot time.
1737 Note that the APM support is almost completely disabled for
1738 machines with more than one CPU.
1740 In order to use APM, you will need supporting software. For location
1741 and more information, read <file:Documentation/power/apm-acpi.txt>
1742 and the Battery Powered Linux mini-HOWTO, available from
1743 <http://www.tldp.org/docs.html#howto>.
1745 This driver does not spin down disk drives (see the hdparm(8)
1746 manpage ("man 8 hdparm") for that), and it doesn't turn off
1747 VESA-compliant "green" monitors.
1749 This driver does not support the TI 4000M TravelMate and the ACER
1750 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1751 desktop machines also don't have compliant BIOSes, and this driver
1752 may cause those machines to panic during the boot phase.
1754 Generally, if you don't have a battery in your machine, there isn't
1755 much point in using this driver and you should say N. If you get
1756 random kernel OOPSes or reboots that don't seem to be related to
1757 anything, try disabling/enabling this option (or disabling/enabling
1760 Some other things you should try when experiencing seemingly random,
1763 1) make sure that you have enough swap space and that it is
1765 2) pass the "no-hlt" option to the kernel
1766 3) switch on floating point emulation in the kernel and pass
1767 the "no387" option to the kernel
1768 4) pass the "floppy=nodma" option to the kernel
1769 5) pass the "mem=4M" option to the kernel (thereby disabling
1770 all but the first 4 MB of RAM)
1771 6) make sure that the CPU is not over clocked.
1772 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1773 8) disable the cache from your BIOS settings
1774 9) install a fan for the video card or exchange video RAM
1775 10) install a better fan for the CPU
1776 11) exchange RAM chips
1777 12) exchange the motherboard.
1779 To compile this driver as a module, choose M here: the
1780 module will be called apm.
1784 config APM_IGNORE_USER_SUSPEND
1785 bool "Ignore USER SUSPEND"
1787 This option will ignore USER SUSPEND requests. On machines with a
1788 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1789 series notebooks, it is necessary to say Y because of a BIOS bug.
1791 config APM_DO_ENABLE
1792 bool "Enable PM at boot time"
1794 Enable APM features at boot time. From page 36 of the APM BIOS
1795 specification: "When disabled, the APM BIOS does not automatically
1796 power manage devices, enter the Standby State, enter the Suspend
1797 State, or take power saving steps in response to CPU Idle calls."
1798 This driver will make CPU Idle calls when Linux is idle (unless this
1799 feature is turned off -- see "Do CPU IDLE calls", below). This
1800 should always save battery power, but more complicated APM features
1801 will be dependent on your BIOS implementation. You may need to turn
1802 this option off if your computer hangs at boot time when using APM
1803 support, or if it beeps continuously instead of suspending. Turn
1804 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1805 T400CDT. This is off by default since most machines do fine without
1809 bool "Make CPU Idle calls when idle"
1811 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1812 On some machines, this can activate improved power savings, such as
1813 a slowed CPU clock rate, when the machine is idle. These idle calls
1814 are made after the idle loop has run for some length of time (e.g.,
1815 333 mS). On some machines, this will cause a hang at boot time or
1816 whenever the CPU becomes idle. (On machines with more than one CPU,
1817 this option does nothing.)
1819 config APM_DISPLAY_BLANK
1820 bool "Enable console blanking using APM"
1822 Enable console blanking using the APM. Some laptops can use this to
1823 turn off the LCD backlight when the screen blanker of the Linux
1824 virtual console blanks the screen. Note that this is only used by
1825 the virtual console screen blanker, and won't turn off the backlight
1826 when using the X Window system. This also doesn't have anything to
1827 do with your VESA-compliant power-saving monitor. Further, this
1828 option doesn't work for all laptops -- it might not turn off your
1829 backlight at all, or it might print a lot of errors to the console,
1830 especially if you are using gpm.
1832 config APM_ALLOW_INTS
1833 bool "Allow interrupts during APM BIOS calls"
1835 Normally we disable external interrupts while we are making calls to
1836 the APM BIOS as a measure to lessen the effects of a badly behaving
1837 BIOS implementation. The BIOS should reenable interrupts if it
1838 needs to. Unfortunately, some BIOSes do not -- especially those in
1839 many of the newer IBM Thinkpads. If you experience hangs when you
1840 suspend, try setting this to Y. Otherwise, say N.
1844 source "drivers/cpufreq/Kconfig"
1846 source "drivers/cpuidle/Kconfig"
1848 source "drivers/idle/Kconfig"
1853 menu "Bus options (PCI etc.)"
1858 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1860 Find out whether you have a PCI motherboard. PCI is the name of a
1861 bus system, i.e. the way the CPU talks to the other stuff inside
1862 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1863 VESA. If you have PCI, say Y, otherwise N.
1866 prompt "PCI access mode"
1867 depends on X86_32 && PCI
1870 On PCI systems, the BIOS can be used to detect the PCI devices and
1871 determine their configuration. However, some old PCI motherboards
1872 have BIOS bugs and may crash if this is done. Also, some embedded
1873 PCI-based systems don't have any BIOS at all. Linux can also try to
1874 detect the PCI hardware directly without using the BIOS.
1876 With this option, you can specify how Linux should detect the
1877 PCI devices. If you choose "BIOS", the BIOS will be used,
1878 if you choose "Direct", the BIOS won't be used, and if you
1879 choose "MMConfig", then PCI Express MMCONFIG will be used.
1880 If you choose "Any", the kernel will try MMCONFIG, then the
1881 direct access method and falls back to the BIOS if that doesn't
1882 work. If unsure, go with the default, which is "Any".
1887 config PCI_GOMMCONFIG
1904 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1906 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1909 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
1913 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1917 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1921 depends on PCI && XEN
1929 bool "Support mmconfig PCI config space access"
1930 depends on X86_64 && PCI && ACPI
1932 config PCI_CNB20LE_QUIRK
1933 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1935 depends on PCI && EXPERIMENTAL
1937 Read the PCI windows out of the CNB20LE host bridge. This allows
1938 PCI hotplug to work on systems with the CNB20LE chipset which do
1941 There's no public spec for this chipset, and this functionality
1942 is known to be incomplete.
1944 You should say N unless you know you need this.
1946 source "drivers/pci/pcie/Kconfig"
1948 source "drivers/pci/Kconfig"
1950 # x86_64 have no ISA slots, but can have ISA-style DMA.
1952 bool "ISA-style DMA support" if (X86_64 && EXPERT)
1955 Enables ISA-style DMA support for devices requiring such controllers.
1963 Find out whether you have ISA slots on your motherboard. ISA is the
1964 name of a bus system, i.e. the way the CPU talks to the other stuff
1965 inside your box. Other bus systems are PCI, EISA, MicroChannel
1966 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1967 newer boards don't support it. If you have ISA, say Y, otherwise N.
1973 The Extended Industry Standard Architecture (EISA) bus was
1974 developed as an open alternative to the IBM MicroChannel bus.
1976 The EISA bus provided some of the features of the IBM MicroChannel
1977 bus while maintaining backward compatibility with cards made for
1978 the older ISA bus. The EISA bus saw limited use between 1988 and
1979 1995 when it was made obsolete by the PCI bus.
1981 Say Y here if you are building a kernel for an EISA-based machine.
1985 source "drivers/eisa/Kconfig"
1990 MicroChannel Architecture is found in some IBM PS/2 machines and
1991 laptops. It is a bus system similar to PCI or ISA. See
1992 <file:Documentation/mca.txt> (and especially the web page given
1993 there) before attempting to build an MCA bus kernel.
1995 source "drivers/mca/Kconfig"
1998 tristate "NatSemi SCx200 support"
2000 This provides basic support for National Semiconductor's
2001 (now AMD's) Geode processors. The driver probes for the
2002 PCI-IDs of several on-chip devices, so its a good dependency
2003 for other scx200_* drivers.
2005 If compiled as a module, the driver is named scx200.
2007 config SCx200HR_TIMER
2008 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2012 This driver provides a clocksource built upon the on-chip
2013 27MHz high-resolution timer. Its also a workaround for
2014 NSC Geode SC-1100's buggy TSC, which loses time when the
2015 processor goes idle (as is done by the scheduler). The
2016 other workaround is idle=poll boot option.
2019 bool "One Laptop Per Child support"
2025 Add support for detecting the unique features of the OLPC
2029 bool "OLPC XO-1 Power Management"
2030 depends on OLPC && MFD_CS5535 && PM_SLEEP
2033 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2036 bool "OLPC XO-1 Real Time Clock"
2037 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2039 Add support for the XO-1 real time clock, which can be used as a
2040 programmable wakeup source.
2043 bool "OLPC XO-1 SCI extras"
2044 depends on OLPC && OLPC_XO1_PM
2049 Add support for SCI-based features of the OLPC XO-1 laptop:
2050 - EC-driven system wakeups
2054 - AC adapter status updates
2055 - Battery status updates
2057 config OLPC_XO15_SCI
2058 bool "OLPC XO-1.5 SCI extras"
2059 depends on OLPC && ACPI
2062 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2063 - EC-driven system wakeups
2064 - AC adapter status updates
2065 - Battery status updates
2071 depends on CPU_SUP_AMD && PCI
2073 source "drivers/pcmcia/Kconfig"
2075 source "drivers/pci/hotplug/Kconfig"
2078 bool "RapidIO support"
2082 If you say Y here, the kernel will include drivers and
2083 infrastructure code to support RapidIO interconnect devices.
2085 source "drivers/rapidio/Kconfig"
2090 menu "Executable file formats / Emulations"
2092 source "fs/Kconfig.binfmt"
2094 config IA32_EMULATION
2095 bool "IA32 Emulation"
2097 select COMPAT_BINFMT_ELF
2099 Include code to run 32-bit programs under a 64-bit kernel. You should
2100 likely turn this on, unless you're 100% sure that you don't have any
2101 32-bit programs left.
2104 tristate "IA32 a.out support"
2105 depends on IA32_EMULATION
2107 Support old a.out binaries in the 32bit emulation.
2111 depends on IA32_EMULATION
2113 config COMPAT_FOR_U64_ALIGNMENT
2117 config SYSVIPC_COMPAT
2119 depends on COMPAT && SYSVIPC
2123 depends on COMPAT && KEYS
2129 config HAVE_ATOMIC_IOMAP
2133 config HAVE_TEXT_POKE_SMP
2135 select STOP_MACHINE if SMP
2137 source "net/Kconfig"
2139 source "drivers/Kconfig"
2141 source "drivers/firmware/Kconfig"
2145 source "arch/x86/Kconfig.debug"
2147 source "security/Kconfig"
2149 source "crypto/Kconfig"
2151 source "arch/x86/kvm/Kconfig"
2153 source "lib/Kconfig"