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
15 select X86_DEV_DMA_OPS
20 select HAVE_AOUT if X86_32
21 select HAVE_UNSTABLE_SCHED_CLOCK
24 select HAVE_PCSPKR_PLATFORM
25 select HAVE_PERF_EVENTS
27 select HAVE_IOREMAP_PROT
30 select HAVE_MEMBLOCK_NODE_MAP
31 select ARCH_DISCARD_MEMBLOCK
32 select ARCH_WANT_OPTIONAL_GPIOLIB
33 select ARCH_WANT_FRAME_POINTERS
35 select HAVE_DMA_CONTIGUOUS if !SWIOTLB
36 select HAVE_KRETPROBES
38 select HAVE_FTRACE_MCOUNT_RECORD
39 select HAVE_C_RECORDMCOUNT
40 select HAVE_DYNAMIC_FTRACE
41 select HAVE_FUNCTION_TRACER
42 select HAVE_FUNCTION_GRAPH_TRACER
43 select HAVE_FUNCTION_GRAPH_FP_TEST
44 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
45 select HAVE_SYSCALL_TRACEPOINTS
48 select HAVE_ARCH_TRACEHOOK
49 select HAVE_GENERIC_DMA_COHERENT if X86_32
50 select HAVE_EFFICIENT_UNALIGNED_ACCESS
51 select USER_STACKTRACE_SUPPORT
52 select HAVE_REGS_AND_STACK_ACCESS_API
53 select HAVE_DMA_API_DEBUG
54 select HAVE_KERNEL_GZIP
55 select HAVE_KERNEL_BZIP2
56 select HAVE_KERNEL_LZMA
58 select HAVE_KERNEL_LZO
59 select HAVE_HW_BREAKPOINT
60 select HAVE_MIXED_BREAKPOINTS_REGS
62 select HAVE_PERF_EVENTS_NMI
64 select HAVE_ALIGNED_STRUCT_PAGE if SLUB && !M386
65 select HAVE_CMPXCHG_LOCAL if !M386
66 select HAVE_CMPXCHG_DOUBLE
67 select HAVE_ARCH_KMEMCHECK
68 select HAVE_USER_RETURN_NOTIFIER
69 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
70 select HAVE_ARCH_JUMP_LABEL
71 select HAVE_TEXT_POKE_SMP
72 select HAVE_GENERIC_HARDIRQS
73 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
75 select GENERIC_FIND_FIRST_BIT
76 select GENERIC_IRQ_PROBE
77 select GENERIC_PENDING_IRQ if SMP
78 select GENERIC_IRQ_SHOW
79 select GENERIC_CLOCKEVENTS_MIN_ADJUST
80 select IRQ_FORCED_THREADING
81 select USE_GENERIC_SMP_HELPERS if SMP
82 select HAVE_BPF_JIT if X86_64
84 select ARCH_HAVE_NMI_SAFE_CMPXCHG
86 select DCACHE_WORD_ACCESS
87 select GENERIC_SMP_IDLE_THREAD
88 select ARCH_WANT_IPC_PARSE_VERSION if X86_32
89 select HAVE_ARCH_SECCOMP_FILTER
90 select BUILDTIME_EXTABLE_SORT
91 select GENERIC_CMOS_UPDATE
92 select CLOCKSOURCE_WATCHDOG
93 select GENERIC_CLOCKEVENTS
94 select ARCH_CLOCKSOURCE_DATA if X86_64
95 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
96 select GENERIC_TIME_VSYSCALL if X86_64
97 select KTIME_SCALAR if X86_32
98 select GENERIC_STRNCPY_FROM_USER
99 select GENERIC_STRNLEN_USER
100 select HAVE_RCU_USER_QS if X86_64
102 config INSTRUCTION_DECODER
103 def_bool (KPROBES || PERF_EVENTS || UPROBES)
107 default "elf32-i386" if X86_32
108 default "elf64-x86-64" if X86_64
110 config ARCH_DEFCONFIG
112 default "arch/x86/configs/i386_defconfig" if X86_32
113 default "arch/x86/configs/x86_64_defconfig" if X86_64
115 config LOCKDEP_SUPPORT
118 config STACKTRACE_SUPPORT
121 config HAVE_LATENCYTOP_SUPPORT
130 config NEED_DMA_MAP_STATE
131 def_bool (X86_64 || INTEL_IOMMU || DMA_API_DEBUG)
133 config NEED_SG_DMA_LENGTH
136 config GENERIC_ISA_DMA
142 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
144 config GENERIC_BUG_RELATIVE_POINTERS
147 config GENERIC_HWEIGHT
153 config ARCH_MAY_HAVE_PC_FDC
156 config RWSEM_GENERIC_SPINLOCK
159 config RWSEM_XCHGADD_ALGORITHM
162 config GENERIC_CALIBRATE_DELAY
165 config ARCH_HAS_CPU_RELAX
168 config ARCH_HAS_DEFAULT_IDLE
171 config ARCH_HAS_CACHE_LINE_SIZE
174 config ARCH_HAS_CPU_AUTOPROBE
177 config HAVE_SETUP_PER_CPU_AREA
180 config NEED_PER_CPU_EMBED_FIRST_CHUNK
183 config NEED_PER_CPU_PAGE_FIRST_CHUNK
186 config ARCH_HIBERNATION_POSSIBLE
189 config ARCH_SUSPEND_POSSIBLE
200 config ARCH_SUPPORTS_OPTIMIZED_INLINING
203 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
206 config HAVE_INTEL_TXT
208 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
212 depends on X86_32 && SMP
216 depends on X86_64 && SMP
222 config X86_32_LAZY_GS
224 depends on X86_32 && !CC_STACKPROTECTOR
226 config ARCH_HWEIGHT_CFLAGS
228 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
229 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
231 config ARCH_CPU_PROBE_RELEASE
233 depends on HOTPLUG_CPU
235 config ARCH_SUPPORTS_UPROBES
238 source "init/Kconfig"
239 source "kernel/Kconfig.freezer"
241 menu "Processor type and features"
244 bool "DMA memory allocation support" if EXPERT
247 DMA memory allocation support allows devices with less than 32-bit
248 addressing to allocate within the first 16MB of address space.
249 Disable if no such devices will be used.
254 bool "Symmetric multi-processing support"
256 This enables support for systems with more than one CPU. If you have
257 a system with only one CPU, like most personal computers, say N. If
258 you have a system with more than one CPU, say Y.
260 If you say N here, the kernel will run on single and multiprocessor
261 machines, but will use only one CPU of a multiprocessor machine. If
262 you say Y here, the kernel will run on many, but not all,
263 singleprocessor machines. On a singleprocessor machine, the kernel
264 will run faster if you say N here.
266 Note that if you say Y here and choose architecture "586" or
267 "Pentium" under "Processor family", the kernel will not work on 486
268 architectures. Similarly, multiprocessor kernels for the "PPro"
269 architecture may not work on all Pentium based boards.
271 People using multiprocessor machines who say Y here should also say
272 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
273 Management" code will be disabled if you say Y here.
275 See also <file:Documentation/x86/i386/IO-APIC.txt>,
276 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
277 <http://www.tldp.org/docs.html#howto>.
279 If you don't know what to do here, say N.
282 bool "Support x2apic"
283 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
285 This enables x2apic support on CPUs that have this feature.
287 This allows 32-bit apic IDs (so it can support very large systems),
288 and accesses the local apic via MSRs not via mmio.
290 If you don't know what to do here, say N.
293 bool "Enable MPS table" if ACPI
295 depends on X86_LOCAL_APIC
297 For old smp systems that do not have proper acpi support. Newer systems
298 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
301 bool "Support for big SMP systems with more than 8 CPUs"
302 depends on X86_32 && SMP
304 This option is needed for the systems that have more than 8 CPUs
307 config X86_EXTENDED_PLATFORM
308 bool "Support for extended (non-PC) x86 platforms"
311 If you disable this option then the kernel will only support
312 standard PC platforms. (which covers the vast majority of
315 If you enable this option then you'll be able to select support
316 for the following (non-PC) 32 bit x86 platforms:
320 SGI 320/540 (Visual Workstation)
321 STA2X11-based (e.g. Northville)
322 Summit/EXA (IBM x440)
323 Unisys ES7000 IA32 series
324 Moorestown MID devices
326 If you have one of these systems, or if you want to build a
327 generic distribution kernel, say Y here - otherwise say N.
331 config X86_EXTENDED_PLATFORM
332 bool "Support for extended (non-PC) x86 platforms"
335 If you disable this option then the kernel will only support
336 standard PC platforms. (which covers the vast majority of
339 If you enable this option then you'll be able to select support
340 for the following (non-PC) 64 bit x86 platforms:
345 If you have one of these systems, or if you want to build a
346 generic distribution kernel, say Y here - otherwise say N.
348 # This is an alphabetically sorted list of 64 bit extended platforms
349 # Please maintain the alphabetic order if and when there are additions
351 bool "Numascale NumaChip"
353 depends on X86_EXTENDED_PLATFORM
356 depends on X86_X2APIC
358 Adds support for Numascale NumaChip large-SMP systems. Needed to
359 enable more than ~168 cores.
360 If you don't have one of these, you should say N here.
364 select PARAVIRT_GUEST
366 depends on X86_64 && PCI
367 depends on X86_EXTENDED_PLATFORM
370 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
371 supposed to run on these EM64T-based machines. Only choose this option
372 if you have one of these machines.
375 bool "SGI Ultraviolet"
377 depends on X86_EXTENDED_PLATFORM
379 depends on X86_X2APIC
381 This option is needed in order to support SGI Ultraviolet systems.
382 If you don't have one of these, you should say N here.
384 # Following is an alphabetically sorted list of 32 bit extended platforms
385 # Please maintain the alphabetic order if and when there are additions
388 bool "CE4100 TV platform"
390 depends on PCI_GODIRECT
392 depends on X86_EXTENDED_PLATFORM
393 select X86_REBOOTFIXUPS
395 select OF_EARLY_FLATTREE
398 Select for the Intel CE media processor (CE4100) SOC.
399 This option compiles in support for the CE4100 SOC for settop
400 boxes and media devices.
402 config X86_WANT_INTEL_MID
403 bool "Intel MID platform support"
405 depends on X86_EXTENDED_PLATFORM
407 Select to build a kernel capable of supporting Intel MID platform
408 systems which do not have the PCI legacy interfaces (Moorestown,
409 Medfield). If you are building for a PC class system say N here.
411 if X86_WANT_INTEL_MID
417 bool "Medfield MID platform"
420 depends on X86_IO_APIC
428 select X86_PLATFORM_DEVICES
429 select MFD_INTEL_MSIC
431 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
432 Internet Device(MID) platform.
433 Unlike standard x86 PCs, Medfield does not have many legacy devices
434 nor standard legacy replacement devices/features. e.g. Medfield does
435 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
440 bool "RDC R-321x SoC"
442 depends on X86_EXTENDED_PLATFORM
444 select X86_REBOOTFIXUPS
446 This option is needed for RDC R-321x system-on-chip, also known
448 If you don't have one of these chips, you should say N here.
450 config X86_32_NON_STANDARD
451 bool "Support non-standard 32-bit SMP architectures"
452 depends on X86_32 && SMP
453 depends on X86_EXTENDED_PLATFORM
455 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
456 STA2X11, default subarchitectures. It is intended for a generic
457 binary kernel. If you select them all, kernel will probe it
458 one by one and will fallback to default.
460 # Alphabetically sorted list of Non standard 32 bit platforms
463 bool "NUMAQ (IBM/Sequent)"
464 depends on X86_32_NON_STANDARD
469 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
470 NUMA multiquad box. This changes the way that processors are
471 bootstrapped, and uses Clustered Logical APIC addressing mode instead
472 of Flat Logical. You will need a new lynxer.elf file to flash your
473 firmware with - send email to <Martin.Bligh@us.ibm.com>.
475 config X86_SUPPORTS_MEMORY_FAILURE
477 # MCE code calls memory_failure():
479 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
480 depends on !X86_NUMAQ
481 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
482 depends on X86_64 || !SPARSEMEM
483 select ARCH_SUPPORTS_MEMORY_FAILURE
486 bool "SGI 320/540 (Visual Workstation)"
487 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
488 depends on X86_32_NON_STANDARD
490 The SGI Visual Workstation series is an IA32-based workstation
491 based on SGI systems chips with some legacy PC hardware attached.
493 Say Y here to create a kernel to run on the SGI 320 or 540.
495 A kernel compiled for the Visual Workstation will run on general
496 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
499 bool "STA2X11 Companion Chip Support"
500 depends on X86_32_NON_STANDARD && PCI
501 select X86_DEV_DMA_OPS
505 select ARCH_REQUIRE_GPIOLIB
508 This adds support for boards based on the STA2X11 IO-Hub,
509 a.k.a. "ConneXt". The chip is used in place of the standard
510 PC chipset, so all "standard" peripherals are missing. If this
511 option is selected the kernel will still be able to boot on
512 standard PC machines.
515 bool "Summit/EXA (IBM x440)"
516 depends on X86_32_NON_STANDARD
518 This option is needed for IBM systems that use the Summit/EXA chipset.
519 In particular, it is needed for the x440.
522 bool "Unisys ES7000 IA32 series"
523 depends on X86_32_NON_STANDARD && X86_BIGSMP
525 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
526 supposed to run on an IA32-based Unisys ES7000 system.
529 tristate "Eurobraille/Iris poweroff module"
532 The Iris machines from EuroBraille do not have APM or ACPI support
533 to shut themselves down properly. A special I/O sequence is
534 needed to do so, which is what this module does at
537 This is only for Iris machines from EuroBraille.
541 config SCHED_OMIT_FRAME_POINTER
543 prompt "Single-depth WCHAN output"
546 Calculate simpler /proc/<PID>/wchan values. If this option
547 is disabled then wchan values will recurse back to the
548 caller function. This provides more accurate wchan values,
549 at the expense of slightly more scheduling overhead.
551 If in doubt, say "Y".
553 menuconfig PARAVIRT_GUEST
554 bool "Paravirtualized guest support"
556 Say Y here to get to see options related to running Linux under
557 various hypervisors. This option alone does not add any kernel code.
559 If you say N, all options in this submenu will be skipped and disabled.
563 config PARAVIRT_TIME_ACCOUNTING
564 bool "Paravirtual steal time accounting"
568 Select this option to enable fine granularity task steal time
569 accounting. Time spent executing other tasks in parallel with
570 the current vCPU is discounted from the vCPU power. To account for
571 that, there can be a small performance impact.
573 If in doubt, say N here.
575 source "arch/x86/xen/Kconfig"
578 bool "KVM paravirtualized clock"
580 select PARAVIRT_CLOCK
582 Turning on this option will allow you to run a paravirtualized clock
583 when running over the KVM hypervisor. Instead of relying on a PIT
584 (or probably other) emulation by the underlying device model, the host
585 provides the guest with timing infrastructure such as time of day, and
589 bool "KVM Guest support"
592 This option enables various optimizations for running under the KVM
595 source "arch/x86/lguest/Kconfig"
598 bool "Enable paravirtualization code"
600 This changes the kernel so it can modify itself when it is run
601 under a hypervisor, potentially improving performance significantly
602 over full virtualization. However, when run without a hypervisor
603 the kernel is theoretically slower and slightly larger.
605 config PARAVIRT_SPINLOCKS
606 bool "Paravirtualization layer for spinlocks"
607 depends on PARAVIRT && SMP && EXPERIMENTAL
609 Paravirtualized spinlocks allow a pvops backend to replace the
610 spinlock implementation with something virtualization-friendly
611 (for example, block the virtual CPU rather than spinning).
613 Unfortunately the downside is an up to 5% performance hit on
614 native kernels, with various workloads.
616 If you are unsure how to answer this question, answer N.
618 config PARAVIRT_CLOCK
623 config PARAVIRT_DEBUG
624 bool "paravirt-ops debugging"
625 depends on PARAVIRT && DEBUG_KERNEL
627 Enable to debug paravirt_ops internals. Specifically, BUG if
628 a paravirt_op is missing when it is called.
636 This option adds a kernel parameter 'memtest', which allows memtest
638 memtest=0, mean disabled; -- default
639 memtest=1, mean do 1 test pattern;
641 memtest=4, mean do 4 test patterns.
642 If you are unsure how to answer this question, answer N.
644 config X86_SUMMIT_NUMA
646 depends on X86_32 && NUMA && X86_32_NON_STANDARD
648 config X86_CYCLONE_TIMER
650 depends on X86_SUMMIT
652 source "arch/x86/Kconfig.cpu"
656 prompt "HPET Timer Support" if X86_32
658 Use the IA-PC HPET (High Precision Event Timer) to manage
659 time in preference to the PIT and RTC, if a HPET is
661 HPET is the next generation timer replacing legacy 8254s.
662 The HPET provides a stable time base on SMP
663 systems, unlike the TSC, but it is more expensive to access,
664 as it is off-chip. You can find the HPET spec at
665 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
667 You can safely choose Y here. However, HPET will only be
668 activated if the platform and the BIOS support this feature.
669 Otherwise the 8254 will be used for timing services.
671 Choose N to continue using the legacy 8254 timer.
673 config HPET_EMULATE_RTC
675 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
678 def_bool y if X86_INTEL_MID
679 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
681 depends on X86_INTEL_MID && SFI
683 APB timer is the replacement for 8254, HPET on X86 MID platforms.
684 The APBT provides a stable time base on SMP
685 systems, unlike the TSC, but it is more expensive to access,
686 as it is off-chip. APB timers are always running regardless of CPU
687 C states, they are used as per CPU clockevent device when possible.
689 # Mark as expert because too many people got it wrong.
690 # The code disables itself when not needed.
693 bool "Enable DMI scanning" if EXPERT
695 Enabled scanning of DMI to identify machine quirks. Say Y
696 here unless you have verified that your setup is not
697 affected by entries in the DMI blacklist. Required by PNP
701 bool "GART IOMMU support" if EXPERT
704 depends on X86_64 && PCI && AMD_NB
706 Support for full DMA access of devices with 32bit memory access only
707 on systems with more than 3GB. This is usually needed for USB,
708 sound, many IDE/SATA chipsets and some other devices.
709 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
710 based hardware IOMMU and a software bounce buffer based IOMMU used
711 on Intel systems and as fallback.
712 The code is only active when needed (enough memory and limited
713 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
717 bool "IBM Calgary IOMMU support"
719 depends on X86_64 && PCI && EXPERIMENTAL
721 Support for hardware IOMMUs in IBM's xSeries x366 and x460
722 systems. Needed to run systems with more than 3GB of memory
723 properly with 32-bit PCI devices that do not support DAC
724 (Double Address Cycle). Calgary also supports bus level
725 isolation, where all DMAs pass through the IOMMU. This
726 prevents them from going anywhere except their intended
727 destination. This catches hard-to-find kernel bugs and
728 mis-behaving drivers and devices that do not use the DMA-API
729 properly to set up their DMA buffers. The IOMMU can be
730 turned off at boot time with the iommu=off parameter.
731 Normally the kernel will make the right choice by itself.
734 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
736 prompt "Should Calgary be enabled by default?"
737 depends on CALGARY_IOMMU
739 Should Calgary be enabled by default? if you choose 'y', Calgary
740 will be used (if it exists). If you choose 'n', Calgary will not be
741 used even if it exists. If you choose 'n' and would like to use
742 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
745 # need this always selected by IOMMU for the VIA workaround
749 Support for software bounce buffers used on x86-64 systems
750 which don't have a hardware IOMMU. Using this PCI devices
751 which can only access 32-bits of memory can be used on systems
752 with more than 3 GB of memory.
756 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
759 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
760 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
761 select CPUMASK_OFFSTACK
763 Enable maximum number of CPUS and NUMA Nodes for this architecture.
767 int "Maximum number of CPUs" if SMP && !MAXSMP
768 range 2 8 if SMP && X86_32 && !X86_BIGSMP
769 range 2 512 if SMP && !MAXSMP
771 default "4096" if MAXSMP
772 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
775 This allows you to specify the maximum number of CPUs which this
776 kernel will support. The maximum supported value is 512 and the
777 minimum value which makes sense is 2.
779 This is purely to save memory - each supported CPU adds
780 approximately eight kilobytes to the kernel image.
783 bool "SMT (Hyperthreading) scheduler support"
786 SMT scheduler support improves the CPU scheduler's decision making
787 when dealing with Intel Pentium 4 chips with HyperThreading at a
788 cost of slightly increased overhead in some places. If unsure say
793 prompt "Multi-core scheduler support"
796 Multi-core scheduler support improves the CPU scheduler's decision
797 making when dealing with multi-core CPU chips at a cost of slightly
798 increased overhead in some places. If unsure say N here.
800 config IRQ_TIME_ACCOUNTING
801 bool "Fine granularity task level IRQ time accounting"
804 Select this option to enable fine granularity task irq time
805 accounting. This is done by reading a timestamp on each
806 transitions between softirq and hardirq state, so there can be a
807 small performance impact.
809 If in doubt, say N here.
811 source "kernel/Kconfig.preempt"
814 bool "Local APIC support on uniprocessors"
815 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
817 A local APIC (Advanced Programmable Interrupt Controller) is an
818 integrated interrupt controller in the CPU. If you have a single-CPU
819 system which has a processor with a local APIC, you can say Y here to
820 enable and use it. If you say Y here even though your machine doesn't
821 have a local APIC, then the kernel will still run with no slowdown at
822 all. The local APIC supports CPU-generated self-interrupts (timer,
823 performance counters), and the NMI watchdog which detects hard
827 bool "IO-APIC support on uniprocessors"
828 depends on X86_UP_APIC
830 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
831 SMP-capable replacement for PC-style interrupt controllers. Most
832 SMP systems and many recent uniprocessor systems have one.
834 If you have a single-CPU system with an IO-APIC, you can say Y here
835 to use it. If you say Y here even though your machine doesn't have
836 an IO-APIC, then the kernel will still run with no slowdown at all.
838 config X86_LOCAL_APIC
840 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
844 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
846 config X86_VISWS_APIC
848 depends on X86_32 && X86_VISWS
850 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
851 bool "Reroute for broken boot IRQs"
852 depends on X86_IO_APIC
854 This option enables a workaround that fixes a source of
855 spurious interrupts. This is recommended when threaded
856 interrupt handling is used on systems where the generation of
857 superfluous "boot interrupts" cannot be disabled.
859 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
860 entry in the chipset's IO-APIC is masked (as, e.g. the RT
861 kernel does during interrupt handling). On chipsets where this
862 boot IRQ generation cannot be disabled, this workaround keeps
863 the original IRQ line masked so that only the equivalent "boot
864 IRQ" is delivered to the CPUs. The workaround also tells the
865 kernel to set up the IRQ handler on the boot IRQ line. In this
866 way only one interrupt is delivered to the kernel. Otherwise
867 the spurious second interrupt may cause the kernel to bring
868 down (vital) interrupt lines.
870 Only affects "broken" chipsets. Interrupt sharing may be
871 increased on these systems.
874 bool "Machine Check / overheating reporting"
876 Machine Check support allows the processor to notify the
877 kernel if it detects a problem (e.g. overheating, data corruption).
878 The action the kernel takes depends on the severity of the problem,
879 ranging from warning messages to halting the machine.
883 prompt "Intel MCE features"
884 depends on X86_MCE && X86_LOCAL_APIC
886 Additional support for intel specific MCE features such as
891 prompt "AMD MCE features"
892 depends on X86_MCE && X86_LOCAL_APIC
894 Additional support for AMD specific MCE features such as
895 the DRAM Error Threshold.
897 config X86_ANCIENT_MCE
898 bool "Support for old Pentium 5 / WinChip machine checks"
899 depends on X86_32 && X86_MCE
901 Include support for machine check handling on old Pentium 5 or WinChip
902 systems. These typically need to be enabled explicitely on the command
905 config X86_MCE_THRESHOLD
906 depends on X86_MCE_AMD || X86_MCE_INTEL
909 config X86_MCE_INJECT
911 tristate "Machine check injector support"
913 Provide support for injecting machine checks for testing purposes.
914 If you don't know what a machine check is and you don't do kernel
915 QA it is safe to say n.
917 config X86_THERMAL_VECTOR
919 depends on X86_MCE_INTEL
922 bool "Enable VM86 support" if EXPERT
926 This option is required by programs like DOSEMU to run 16-bit legacy
927 code on X86 processors. It also may be needed by software like
928 XFree86 to initialize some video cards via BIOS. Disabling this
929 option saves about 6k.
932 tristate "Toshiba Laptop support"
935 This adds a driver to safely access the System Management Mode of
936 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
937 not work on models with a Phoenix BIOS. The System Management Mode
938 is used to set the BIOS and power saving options on Toshiba portables.
940 For information on utilities to make use of this driver see the
941 Toshiba Linux utilities web site at:
942 <http://www.buzzard.org.uk/toshiba/>.
944 Say Y if you intend to run this kernel on a Toshiba portable.
948 tristate "Dell laptop support"
951 This adds a driver to safely access the System Management Mode
952 of the CPU on the Dell Inspiron 8000. The System Management Mode
953 is used to read cpu temperature and cooling fan status and to
954 control the fans on the I8K portables.
956 This driver has been tested only on the Inspiron 8000 but it may
957 also work with other Dell laptops. You can force loading on other
958 models by passing the parameter `force=1' to the module. Use at
961 For information on utilities to make use of this driver see the
962 I8K Linux utilities web site at:
963 <http://people.debian.org/~dz/i8k/>
965 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
968 config X86_REBOOTFIXUPS
969 bool "Enable X86 board specific fixups for reboot"
972 This enables chipset and/or board specific fixups to be done
973 in order to get reboot to work correctly. This is only needed on
974 some combinations of hardware and BIOS. The symptom, for which
975 this config is intended, is when reboot ends with a stalled/hung
978 Currently, the only fixup is for the Geode machines using
979 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
981 Say Y if you want to enable the fixup. Currently, it's safe to
982 enable this option even if you don't need it.
986 tristate "/dev/cpu/microcode - microcode support"
989 If you say Y here, you will be able to update the microcode on
990 certain Intel and AMD processors. The Intel support is for the
991 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
992 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
993 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
994 You will obviously need the actual microcode binary data itself
995 which is not shipped with the Linux kernel.
997 This option selects the general module only, you need to select
998 at least one vendor specific module as well.
1000 To compile this driver as a module, choose M here: the
1001 module will be called microcode.
1003 config MICROCODE_INTEL
1004 bool "Intel microcode patch loading support"
1005 depends on MICROCODE
1009 This options enables microcode patch loading support for Intel
1012 For latest news and information on obtaining all the required
1013 Intel ingredients for this driver, check:
1014 <http://www.urbanmyth.org/microcode/>.
1016 config MICROCODE_AMD
1017 bool "AMD microcode patch loading support"
1018 depends on MICROCODE
1021 If you select this option, microcode patch loading support for AMD
1022 processors will be enabled.
1024 config MICROCODE_OLD_INTERFACE
1026 depends on MICROCODE
1029 tristate "/dev/cpu/*/msr - Model-specific register support"
1031 This device gives privileged processes access to the x86
1032 Model-Specific Registers (MSRs). It is a character device with
1033 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1034 MSR accesses are directed to a specific CPU on multi-processor
1038 tristate "/dev/cpu/*/cpuid - CPU information support"
1040 This device gives processes access to the x86 CPUID instruction to
1041 be executed on a specific processor. It is a character device
1042 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1046 prompt "High Memory Support"
1047 default HIGHMEM64G if X86_NUMAQ
1053 depends on !X86_NUMAQ
1055 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1056 However, the address space of 32-bit x86 processors is only 4
1057 Gigabytes large. That means that, if you have a large amount of
1058 physical memory, not all of it can be "permanently mapped" by the
1059 kernel. The physical memory that's not permanently mapped is called
1062 If you are compiling a kernel which will never run on a machine with
1063 more than 1 Gigabyte total physical RAM, answer "off" here (default
1064 choice and suitable for most users). This will result in a "3GB/1GB"
1065 split: 3GB are mapped so that each process sees a 3GB virtual memory
1066 space and the remaining part of the 4GB virtual memory space is used
1067 by the kernel to permanently map as much physical memory as
1070 If the machine has between 1 and 4 Gigabytes physical RAM, then
1073 If more than 4 Gigabytes is used then answer "64GB" here. This
1074 selection turns Intel PAE (Physical Address Extension) mode on.
1075 PAE implements 3-level paging on IA32 processors. PAE is fully
1076 supported by Linux, PAE mode is implemented on all recent Intel
1077 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1078 then the kernel will not boot on CPUs that don't support PAE!
1080 The actual amount of total physical memory will either be
1081 auto detected or can be forced by using a kernel command line option
1082 such as "mem=256M". (Try "man bootparam" or see the documentation of
1083 your boot loader (lilo or loadlin) about how to pass options to the
1084 kernel at boot time.)
1086 If unsure, say "off".
1090 depends on !X86_NUMAQ
1092 Select this if you have a 32-bit processor and between 1 and 4
1093 gigabytes of physical RAM.
1097 depends on !M386 && !M486
1100 Select this if you have a 32-bit processor and more than 4
1101 gigabytes of physical RAM.
1106 depends on EXPERIMENTAL
1107 prompt "Memory split" if EXPERT
1111 Select the desired split between kernel and user memory.
1113 If the address range available to the kernel is less than the
1114 physical memory installed, the remaining memory will be available
1115 as "high memory". Accessing high memory is a little more costly
1116 than low memory, as it needs to be mapped into the kernel first.
1117 Note that increasing the kernel address space limits the range
1118 available to user programs, making the address space there
1119 tighter. Selecting anything other than the default 3G/1G split
1120 will also likely make your kernel incompatible with binary-only
1123 If you are not absolutely sure what you are doing, leave this
1127 bool "3G/1G user/kernel split"
1128 config VMSPLIT_3G_OPT
1130 bool "3G/1G user/kernel split (for full 1G low memory)"
1132 bool "2G/2G user/kernel split"
1133 config VMSPLIT_2G_OPT
1135 bool "2G/2G user/kernel split (for full 2G low memory)"
1137 bool "1G/3G user/kernel split"
1142 default 0xB0000000 if VMSPLIT_3G_OPT
1143 default 0x80000000 if VMSPLIT_2G
1144 default 0x78000000 if VMSPLIT_2G_OPT
1145 default 0x40000000 if VMSPLIT_1G
1151 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1154 bool "PAE (Physical Address Extension) Support"
1155 depends on X86_32 && !HIGHMEM4G
1157 PAE is required for NX support, and furthermore enables
1158 larger swapspace support for non-overcommit purposes. It
1159 has the cost of more pagetable lookup overhead, and also
1160 consumes more pagetable space per process.
1162 config ARCH_PHYS_ADDR_T_64BIT
1163 def_bool X86_64 || X86_PAE
1165 config ARCH_DMA_ADDR_T_64BIT
1166 def_bool X86_64 || HIGHMEM64G
1168 config DIRECT_GBPAGES
1169 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1173 Allow the kernel linear mapping to use 1GB pages on CPUs that
1174 support it. This can improve the kernel's performance a tiny bit by
1175 reducing TLB pressure. If in doubt, say "Y".
1177 # Common NUMA Features
1179 bool "Numa Memory Allocation and Scheduler Support"
1181 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1182 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1184 Enable NUMA (Non Uniform Memory Access) support.
1186 The kernel will try to allocate memory used by a CPU on the
1187 local memory controller of the CPU and add some more
1188 NUMA awareness to the kernel.
1190 For 64-bit this is recommended if the system is Intel Core i7
1191 (or later), AMD Opteron, or EM64T NUMA.
1193 For 32-bit this is only needed on (rare) 32-bit-only platforms
1194 that support NUMA topologies, such as NUMAQ / Summit, or if you
1195 boot a 32-bit kernel on a 64-bit NUMA platform.
1197 Otherwise, you should say N.
1199 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1200 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1204 prompt "Old style AMD Opteron NUMA detection"
1205 depends on X86_64 && NUMA && PCI
1207 Enable AMD NUMA node topology detection. You should say Y here if
1208 you have a multi processor AMD system. This uses an old method to
1209 read the NUMA configuration directly from the builtin Northbridge
1210 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1211 which also takes priority if both are compiled in.
1213 config X86_64_ACPI_NUMA
1215 prompt "ACPI NUMA detection"
1216 depends on X86_64 && NUMA && ACPI && PCI
1219 Enable ACPI SRAT based node topology detection.
1221 # Some NUMA nodes have memory ranges that span
1222 # other nodes. Even though a pfn is valid and
1223 # between a node's start and end pfns, it may not
1224 # reside on that node. See memmap_init_zone()
1226 config NODES_SPAN_OTHER_NODES
1228 depends on X86_64_ACPI_NUMA
1231 bool "NUMA emulation"
1234 Enable NUMA emulation. A flat machine will be split
1235 into virtual nodes when booted with "numa=fake=N", where N is the
1236 number of nodes. This is only useful for debugging.
1239 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1241 default "10" if MAXSMP
1242 default "6" if X86_64
1243 default "4" if X86_NUMAQ
1245 depends on NEED_MULTIPLE_NODES
1247 Specify the maximum number of NUMA Nodes available on the target
1248 system. Increases memory reserved to accommodate various tables.
1250 config HAVE_ARCH_ALLOC_REMAP
1252 depends on X86_32 && NUMA
1254 config ARCH_HAVE_MEMORY_PRESENT
1256 depends on X86_32 && DISCONTIGMEM
1258 config NEED_NODE_MEMMAP_SIZE
1260 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1262 config ARCH_FLATMEM_ENABLE
1264 depends on X86_32 && !NUMA
1266 config ARCH_DISCONTIGMEM_ENABLE
1268 depends on NUMA && X86_32
1270 config ARCH_DISCONTIGMEM_DEFAULT
1272 depends on NUMA && X86_32
1274 config ARCH_SPARSEMEM_ENABLE
1276 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1277 select SPARSEMEM_STATIC if X86_32
1278 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1280 config ARCH_SPARSEMEM_DEFAULT
1284 config ARCH_SELECT_MEMORY_MODEL
1286 depends on ARCH_SPARSEMEM_ENABLE
1288 config ARCH_MEMORY_PROBE
1290 depends on MEMORY_HOTPLUG
1292 config ARCH_PROC_KCORE_TEXT
1294 depends on X86_64 && PROC_KCORE
1296 config ILLEGAL_POINTER_VALUE
1299 default 0xdead000000000000 if X86_64
1304 bool "Allocate 3rd-level pagetables from highmem"
1307 The VM uses one page table entry for each page of physical memory.
1308 For systems with a lot of RAM, this can be wasteful of precious
1309 low memory. Setting this option will put user-space page table
1310 entries in high memory.
1312 config X86_CHECK_BIOS_CORRUPTION
1313 bool "Check for low memory corruption"
1315 Periodically check for memory corruption in low memory, which
1316 is suspected to be caused by BIOS. Even when enabled in the
1317 configuration, it is disabled at runtime. Enable it by
1318 setting "memory_corruption_check=1" on the kernel command
1319 line. By default it scans the low 64k of memory every 60
1320 seconds; see the memory_corruption_check_size and
1321 memory_corruption_check_period parameters in
1322 Documentation/kernel-parameters.txt to adjust this.
1324 When enabled with the default parameters, this option has
1325 almost no overhead, as it reserves a relatively small amount
1326 of memory and scans it infrequently. It both detects corruption
1327 and prevents it from affecting the running system.
1329 It is, however, intended as a diagnostic tool; if repeatable
1330 BIOS-originated corruption always affects the same memory,
1331 you can use memmap= to prevent the kernel from using that
1334 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1335 bool "Set the default setting of memory_corruption_check"
1336 depends on X86_CHECK_BIOS_CORRUPTION
1339 Set whether the default state of memory_corruption_check is
1342 config X86_RESERVE_LOW
1343 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1347 Specify the amount of low memory to reserve for the BIOS.
1349 The first page contains BIOS data structures that the kernel
1350 must not use, so that page must always be reserved.
1352 By default we reserve the first 64K of physical RAM, as a
1353 number of BIOSes are known to corrupt that memory range
1354 during events such as suspend/resume or monitor cable
1355 insertion, so it must not be used by the kernel.
1357 You can set this to 4 if you are absolutely sure that you
1358 trust the BIOS to get all its memory reservations and usages
1359 right. If you know your BIOS have problems beyond the
1360 default 64K area, you can set this to 640 to avoid using the
1361 entire low memory range.
1363 If you have doubts about the BIOS (e.g. suspend/resume does
1364 not work or there's kernel crashes after certain hardware
1365 hotplug events) then you might want to enable
1366 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1367 typical corruption patterns.
1369 Leave this to the default value of 64 if you are unsure.
1371 config MATH_EMULATION
1373 prompt "Math emulation" if X86_32
1375 Linux can emulate a math coprocessor (used for floating point
1376 operations) if you don't have one. 486DX and Pentium processors have
1377 a math coprocessor built in, 486SX and 386 do not, unless you added
1378 a 487DX or 387, respectively. (The messages during boot time can
1379 give you some hints here ["man dmesg"].) Everyone needs either a
1380 coprocessor or this emulation.
1382 If you don't have a math coprocessor, you need to say Y here; if you
1383 say Y here even though you have a coprocessor, the coprocessor will
1384 be used nevertheless. (This behavior can be changed with the kernel
1385 command line option "no387", which comes handy if your coprocessor
1386 is broken. Try "man bootparam" or see the documentation of your boot
1387 loader (lilo or loadlin) about how to pass options to the kernel at
1388 boot time.) This means that it is a good idea to say Y here if you
1389 intend to use this kernel on different machines.
1391 More information about the internals of the Linux math coprocessor
1392 emulation can be found in <file:arch/x86/math-emu/README>.
1394 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1395 kernel, it won't hurt.
1399 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1401 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1402 the Memory Type Range Registers (MTRRs) may be used to control
1403 processor access to memory ranges. This is most useful if you have
1404 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1405 allows bus write transfers to be combined into a larger transfer
1406 before bursting over the PCI/AGP bus. This can increase performance
1407 of image write operations 2.5 times or more. Saying Y here creates a
1408 /proc/mtrr file which may be used to manipulate your processor's
1409 MTRRs. Typically the X server should use this.
1411 This code has a reasonably generic interface so that similar
1412 control registers on other processors can be easily supported
1415 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1416 Registers (ARRs) which provide a similar functionality to MTRRs. For
1417 these, the ARRs are used to emulate the MTRRs.
1418 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1419 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1420 write-combining. All of these processors are supported by this code
1421 and it makes sense to say Y here if you have one of them.
1423 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1424 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1425 can lead to all sorts of problems, so it's good to say Y here.
1427 You can safely say Y even if your machine doesn't have MTRRs, you'll
1428 just add about 9 KB to your kernel.
1430 See <file:Documentation/x86/mtrr.txt> for more information.
1432 config MTRR_SANITIZER
1434 prompt "MTRR cleanup support"
1437 Convert MTRR layout from continuous to discrete, so X drivers can
1438 add writeback entries.
1440 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1441 The largest mtrr entry size for a continuous block can be set with
1446 config MTRR_SANITIZER_ENABLE_DEFAULT
1447 int "MTRR cleanup enable value (0-1)"
1450 depends on MTRR_SANITIZER
1452 Enable mtrr cleanup default value
1454 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1455 int "MTRR cleanup spare reg num (0-7)"
1458 depends on MTRR_SANITIZER
1460 mtrr cleanup spare entries default, it can be changed via
1461 mtrr_spare_reg_nr=N on the kernel command line.
1465 prompt "x86 PAT support" if EXPERT
1468 Use PAT attributes to setup page level cache control.
1470 PATs are the modern equivalents of MTRRs and are much more
1471 flexible than MTRRs.
1473 Say N here if you see bootup problems (boot crash, boot hang,
1474 spontaneous reboots) or a non-working video driver.
1478 config ARCH_USES_PG_UNCACHED
1484 prompt "x86 architectural random number generator" if EXPERT
1486 Enable the x86 architectural RDRAND instruction
1487 (Intel Bull Mountain technology) to generate random numbers.
1488 If supported, this is a high bandwidth, cryptographically
1489 secure hardware random number generator.
1492 bool "EFI runtime service support"
1495 This enables the kernel to use EFI runtime services that are
1496 available (such as the EFI variable services).
1498 This option is only useful on systems that have EFI firmware.
1499 In addition, you should use the latest ELILO loader available
1500 at <http://elilo.sourceforge.net> in order to take advantage
1501 of EFI runtime services. However, even with this option, the
1502 resultant kernel should continue to boot on existing non-EFI
1506 bool "EFI stub support"
1509 This kernel feature allows a bzImage to be loaded directly
1510 by EFI firmware without the use of a bootloader.
1512 See Documentation/x86/efi-stub.txt for more information.
1516 prompt "Enable seccomp to safely compute untrusted bytecode"
1518 This kernel feature is useful for number crunching applications
1519 that may need to compute untrusted bytecode during their
1520 execution. By using pipes or other transports made available to
1521 the process as file descriptors supporting the read/write
1522 syscalls, it's possible to isolate those applications in
1523 their own address space using seccomp. Once seccomp is
1524 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1525 and the task is only allowed to execute a few safe syscalls
1526 defined by each seccomp mode.
1528 If unsure, say Y. Only embedded should say N here.
1530 config CC_STACKPROTECTOR
1531 bool "Enable -fstack-protector buffer overflow detection"
1533 This option turns on the -fstack-protector GCC feature. This
1534 feature puts, at the beginning of functions, a canary value on
1535 the stack just before the return address, and validates
1536 the value just before actually returning. Stack based buffer
1537 overflows (that need to overwrite this return address) now also
1538 overwrite the canary, which gets detected and the attack is then
1539 neutralized via a kernel panic.
1541 This feature requires gcc version 4.2 or above, or a distribution
1542 gcc with the feature backported. Older versions are automatically
1543 detected and for those versions, this configuration option is
1544 ignored. (and a warning is printed during bootup)
1546 source kernel/Kconfig.hz
1549 bool "kexec system call"
1551 kexec is a system call that implements the ability to shutdown your
1552 current kernel, and to start another kernel. It is like a reboot
1553 but it is independent of the system firmware. And like a reboot
1554 you can start any kernel with it, not just Linux.
1556 The name comes from the similarity to the exec system call.
1558 It is an ongoing process to be certain the hardware in a machine
1559 is properly shutdown, so do not be surprised if this code does not
1560 initially work for you. It may help to enable device hotplugging
1561 support. As of this writing the exact hardware interface is
1562 strongly in flux, so no good recommendation can be made.
1565 bool "kernel crash dumps"
1566 depends on X86_64 || (X86_32 && HIGHMEM)
1568 Generate crash dump after being started by kexec.
1569 This should be normally only set in special crash dump kernels
1570 which are loaded in the main kernel with kexec-tools into
1571 a specially reserved region and then later executed after
1572 a crash by kdump/kexec. The crash dump kernel must be compiled
1573 to a memory address not used by the main kernel or BIOS using
1574 PHYSICAL_START, or it must be built as a relocatable image
1575 (CONFIG_RELOCATABLE=y).
1576 For more details see Documentation/kdump/kdump.txt
1579 bool "kexec jump (EXPERIMENTAL)"
1580 depends on EXPERIMENTAL
1581 depends on KEXEC && HIBERNATION
1583 Jump between original kernel and kexeced kernel and invoke
1584 code in physical address mode via KEXEC
1586 config PHYSICAL_START
1587 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1590 This gives the physical address where the kernel is loaded.
1592 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1593 bzImage will decompress itself to above physical address and
1594 run from there. Otherwise, bzImage will run from the address where
1595 it has been loaded by the boot loader and will ignore above physical
1598 In normal kdump cases one does not have to set/change this option
1599 as now bzImage can be compiled as a completely relocatable image
1600 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1601 address. This option is mainly useful for the folks who don't want
1602 to use a bzImage for capturing the crash dump and want to use a
1603 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1604 to be specifically compiled to run from a specific memory area
1605 (normally a reserved region) and this option comes handy.
1607 So if you are using bzImage for capturing the crash dump,
1608 leave the value here unchanged to 0x1000000 and set
1609 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1610 for capturing the crash dump change this value to start of
1611 the reserved region. In other words, it can be set based on
1612 the "X" value as specified in the "crashkernel=YM@XM"
1613 command line boot parameter passed to the panic-ed
1614 kernel. Please take a look at Documentation/kdump/kdump.txt
1615 for more details about crash dumps.
1617 Usage of bzImage for capturing the crash dump is recommended as
1618 one does not have to build two kernels. Same kernel can be used
1619 as production kernel and capture kernel. Above option should have
1620 gone away after relocatable bzImage support is introduced. But it
1621 is present because there are users out there who continue to use
1622 vmlinux for dump capture. This option should go away down the
1625 Don't change this unless you know what you are doing.
1628 bool "Build a relocatable kernel"
1631 This builds a kernel image that retains relocation information
1632 so it can be loaded someplace besides the default 1MB.
1633 The relocations tend to make the kernel binary about 10% larger,
1634 but are discarded at runtime.
1636 One use is for the kexec on panic case where the recovery kernel
1637 must live at a different physical address than the primary
1640 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1641 it has been loaded at and the compile time physical address
1642 (CONFIG_PHYSICAL_START) is ignored.
1644 # Relocation on x86-32 needs some additional build support
1645 config X86_NEED_RELOCS
1647 depends on X86_32 && RELOCATABLE
1649 config PHYSICAL_ALIGN
1650 hex "Alignment value to which kernel should be aligned" if X86_32
1652 range 0x2000 0x1000000
1654 This value puts the alignment restrictions on physical address
1655 where kernel is loaded and run from. Kernel is compiled for an
1656 address which meets above alignment restriction.
1658 If bootloader loads the kernel at a non-aligned address and
1659 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1660 address aligned to above value and run from there.
1662 If bootloader loads the kernel at a non-aligned address and
1663 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1664 load address and decompress itself to the address it has been
1665 compiled for and run from there. The address for which kernel is
1666 compiled already meets above alignment restrictions. Hence the
1667 end result is that kernel runs from a physical address meeting
1668 above alignment restrictions.
1670 Don't change this unless you know what you are doing.
1673 bool "Support for hot-pluggable CPUs"
1674 depends on SMP && HOTPLUG
1676 Say Y here to allow turning CPUs off and on. CPUs can be
1677 controlled through /sys/devices/system/cpu.
1678 ( Note: power management support will enable this option
1679 automatically on SMP systems. )
1680 Say N if you want to disable CPU hotplug.
1684 prompt "Compat VDSO support"
1685 depends on X86_32 || IA32_EMULATION
1687 Map the 32-bit VDSO to the predictable old-style address too.
1689 Say N here if you are running a sufficiently recent glibc
1690 version (2.3.3 or later), to remove the high-mapped
1691 VDSO mapping and to exclusively use the randomized VDSO.
1696 bool "Built-in kernel command line"
1698 Allow for specifying boot arguments to the kernel at
1699 build time. On some systems (e.g. embedded ones), it is
1700 necessary or convenient to provide some or all of the
1701 kernel boot arguments with the kernel itself (that is,
1702 to not rely on the boot loader to provide them.)
1704 To compile command line arguments into the kernel,
1705 set this option to 'Y', then fill in the
1706 the boot arguments in CONFIG_CMDLINE.
1708 Systems with fully functional boot loaders (i.e. non-embedded)
1709 should leave this option set to 'N'.
1712 string "Built-in kernel command string"
1713 depends on CMDLINE_BOOL
1716 Enter arguments here that should be compiled into the kernel
1717 image and used at boot time. If the boot loader provides a
1718 command line at boot time, it is appended to this string to
1719 form the full kernel command line, when the system boots.
1721 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1722 change this behavior.
1724 In most cases, the command line (whether built-in or provided
1725 by the boot loader) should specify the device for the root
1728 config CMDLINE_OVERRIDE
1729 bool "Built-in command line overrides boot loader arguments"
1730 depends on CMDLINE_BOOL
1732 Set this option to 'Y' to have the kernel ignore the boot loader
1733 command line, and use ONLY the built-in command line.
1735 This is used to work around broken boot loaders. This should
1736 be set to 'N' under normal conditions.
1740 config ARCH_ENABLE_MEMORY_HOTPLUG
1742 depends on X86_64 || (X86_32 && HIGHMEM)
1744 config ARCH_ENABLE_MEMORY_HOTREMOVE
1746 depends on MEMORY_HOTPLUG
1748 config USE_PERCPU_NUMA_NODE_ID
1752 menu "Power management and ACPI options"
1754 config ARCH_HIBERNATION_HEADER
1756 depends on X86_64 && HIBERNATION
1758 source "kernel/power/Kconfig"
1760 source "drivers/acpi/Kconfig"
1762 source "drivers/sfi/Kconfig"
1769 tristate "APM (Advanced Power Management) BIOS support"
1770 depends on X86_32 && PM_SLEEP
1772 APM is a BIOS specification for saving power using several different
1773 techniques. This is mostly useful for battery powered laptops with
1774 APM compliant BIOSes. If you say Y here, the system time will be
1775 reset after a RESUME operation, the /proc/apm device will provide
1776 battery status information, and user-space programs will receive
1777 notification of APM "events" (e.g. battery status change).
1779 If you select "Y" here, you can disable actual use of the APM
1780 BIOS by passing the "apm=off" option to the kernel at boot time.
1782 Note that the APM support is almost completely disabled for
1783 machines with more than one CPU.
1785 In order to use APM, you will need supporting software. For location
1786 and more information, read <file:Documentation/power/apm-acpi.txt>
1787 and the Battery Powered Linux mini-HOWTO, available from
1788 <http://www.tldp.org/docs.html#howto>.
1790 This driver does not spin down disk drives (see the hdparm(8)
1791 manpage ("man 8 hdparm") for that), and it doesn't turn off
1792 VESA-compliant "green" monitors.
1794 This driver does not support the TI 4000M TravelMate and the ACER
1795 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1796 desktop machines also don't have compliant BIOSes, and this driver
1797 may cause those machines to panic during the boot phase.
1799 Generally, if you don't have a battery in your machine, there isn't
1800 much point in using this driver and you should say N. If you get
1801 random kernel OOPSes or reboots that don't seem to be related to
1802 anything, try disabling/enabling this option (or disabling/enabling
1805 Some other things you should try when experiencing seemingly random,
1808 1) make sure that you have enough swap space and that it is
1810 2) pass the "no-hlt" option to the kernel
1811 3) switch on floating point emulation in the kernel and pass
1812 the "no387" option to the kernel
1813 4) pass the "floppy=nodma" option to the kernel
1814 5) pass the "mem=4M" option to the kernel (thereby disabling
1815 all but the first 4 MB of RAM)
1816 6) make sure that the CPU is not over clocked.
1817 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1818 8) disable the cache from your BIOS settings
1819 9) install a fan for the video card or exchange video RAM
1820 10) install a better fan for the CPU
1821 11) exchange RAM chips
1822 12) exchange the motherboard.
1824 To compile this driver as a module, choose M here: the
1825 module will be called apm.
1829 config APM_IGNORE_USER_SUSPEND
1830 bool "Ignore USER SUSPEND"
1832 This option will ignore USER SUSPEND requests. On machines with a
1833 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1834 series notebooks, it is necessary to say Y because of a BIOS bug.
1836 config APM_DO_ENABLE
1837 bool "Enable PM at boot time"
1839 Enable APM features at boot time. From page 36 of the APM BIOS
1840 specification: "When disabled, the APM BIOS does not automatically
1841 power manage devices, enter the Standby State, enter the Suspend
1842 State, or take power saving steps in response to CPU Idle calls."
1843 This driver will make CPU Idle calls when Linux is idle (unless this
1844 feature is turned off -- see "Do CPU IDLE calls", below). This
1845 should always save battery power, but more complicated APM features
1846 will be dependent on your BIOS implementation. You may need to turn
1847 this option off if your computer hangs at boot time when using APM
1848 support, or if it beeps continuously instead of suspending. Turn
1849 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1850 T400CDT. This is off by default since most machines do fine without
1854 bool "Make CPU Idle calls when idle"
1856 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1857 On some machines, this can activate improved power savings, such as
1858 a slowed CPU clock rate, when the machine is idle. These idle calls
1859 are made after the idle loop has run for some length of time (e.g.,
1860 333 mS). On some machines, this will cause a hang at boot time or
1861 whenever the CPU becomes idle. (On machines with more than one CPU,
1862 this option does nothing.)
1864 config APM_DISPLAY_BLANK
1865 bool "Enable console blanking using APM"
1867 Enable console blanking using the APM. Some laptops can use this to
1868 turn off the LCD backlight when the screen blanker of the Linux
1869 virtual console blanks the screen. Note that this is only used by
1870 the virtual console screen blanker, and won't turn off the backlight
1871 when using the X Window system. This also doesn't have anything to
1872 do with your VESA-compliant power-saving monitor. Further, this
1873 option doesn't work for all laptops -- it might not turn off your
1874 backlight at all, or it might print a lot of errors to the console,
1875 especially if you are using gpm.
1877 config APM_ALLOW_INTS
1878 bool "Allow interrupts during APM BIOS calls"
1880 Normally we disable external interrupts while we are making calls to
1881 the APM BIOS as a measure to lessen the effects of a badly behaving
1882 BIOS implementation. The BIOS should reenable interrupts if it
1883 needs to. Unfortunately, some BIOSes do not -- especially those in
1884 many of the newer IBM Thinkpads. If you experience hangs when you
1885 suspend, try setting this to Y. Otherwise, say N.
1889 source "drivers/cpufreq/Kconfig"
1891 source "drivers/cpuidle/Kconfig"
1893 source "drivers/idle/Kconfig"
1898 menu "Bus options (PCI etc.)"
1903 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1905 Find out whether you have a PCI motherboard. PCI is the name of a
1906 bus system, i.e. the way the CPU talks to the other stuff inside
1907 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1908 VESA. If you have PCI, say Y, otherwise N.
1911 prompt "PCI access mode"
1912 depends on X86_32 && PCI
1915 On PCI systems, the BIOS can be used to detect the PCI devices and
1916 determine their configuration. However, some old PCI motherboards
1917 have BIOS bugs and may crash if this is done. Also, some embedded
1918 PCI-based systems don't have any BIOS at all. Linux can also try to
1919 detect the PCI hardware directly without using the BIOS.
1921 With this option, you can specify how Linux should detect the
1922 PCI devices. If you choose "BIOS", the BIOS will be used,
1923 if you choose "Direct", the BIOS won't be used, and if you
1924 choose "MMConfig", then PCI Express MMCONFIG will be used.
1925 If you choose "Any", the kernel will try MMCONFIG, then the
1926 direct access method and falls back to the BIOS if that doesn't
1927 work. If unsure, go with the default, which is "Any".
1932 config PCI_GOMMCONFIG
1949 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1951 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1954 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
1958 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1962 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1966 depends on PCI && XEN
1974 bool "Support mmconfig PCI config space access"
1975 depends on X86_64 && PCI && ACPI
1977 config PCI_CNB20LE_QUIRK
1978 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1980 depends on PCI && EXPERIMENTAL
1982 Read the PCI windows out of the CNB20LE host bridge. This allows
1983 PCI hotplug to work on systems with the CNB20LE chipset which do
1986 There's no public spec for this chipset, and this functionality
1987 is known to be incomplete.
1989 You should say N unless you know you need this.
1991 source "drivers/pci/pcie/Kconfig"
1993 source "drivers/pci/Kconfig"
1995 # x86_64 have no ISA slots, but can have ISA-style DMA.
1997 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2000 Enables ISA-style DMA support for devices requiring such controllers.
2008 Find out whether you have ISA slots on your motherboard. ISA is the
2009 name of a bus system, i.e. the way the CPU talks to the other stuff
2010 inside your box. Other bus systems are PCI, EISA, MicroChannel
2011 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2012 newer boards don't support it. If you have ISA, say Y, otherwise N.
2018 The Extended Industry Standard Architecture (EISA) bus was
2019 developed as an open alternative to the IBM MicroChannel bus.
2021 The EISA bus provided some of the features of the IBM MicroChannel
2022 bus while maintaining backward compatibility with cards made for
2023 the older ISA bus. The EISA bus saw limited use between 1988 and
2024 1995 when it was made obsolete by the PCI bus.
2026 Say Y here if you are building a kernel for an EISA-based machine.
2030 source "drivers/eisa/Kconfig"
2033 tristate "NatSemi SCx200 support"
2035 This provides basic support for National Semiconductor's
2036 (now AMD's) Geode processors. The driver probes for the
2037 PCI-IDs of several on-chip devices, so its a good dependency
2038 for other scx200_* drivers.
2040 If compiled as a module, the driver is named scx200.
2042 config SCx200HR_TIMER
2043 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2047 This driver provides a clocksource built upon the on-chip
2048 27MHz high-resolution timer. Its also a workaround for
2049 NSC Geode SC-1100's buggy TSC, which loses time when the
2050 processor goes idle (as is done by the scheduler). The
2051 other workaround is idle=poll boot option.
2054 bool "One Laptop Per Child support"
2061 Add support for detecting the unique features of the OLPC
2065 bool "OLPC XO-1 Power Management"
2066 depends on OLPC && MFD_CS5535 && PM_SLEEP
2069 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2072 bool "OLPC XO-1 Real Time Clock"
2073 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2075 Add support for the XO-1 real time clock, which can be used as a
2076 programmable wakeup source.
2079 bool "OLPC XO-1 SCI extras"
2080 depends on OLPC && OLPC_XO1_PM
2085 Add support for SCI-based features of the OLPC XO-1 laptop:
2086 - EC-driven system wakeups
2090 - AC adapter status updates
2091 - Battery status updates
2093 config OLPC_XO15_SCI
2094 bool "OLPC XO-1.5 SCI extras"
2095 depends on OLPC && ACPI
2098 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2099 - EC-driven system wakeups
2100 - AC adapter status updates
2101 - Battery status updates
2104 bool "PCEngines ALIX System Support (LED setup)"
2107 This option enables system support for the PCEngines ALIX.
2108 At present this just sets up LEDs for GPIO control on
2109 ALIX2/3/6 boards. However, other system specific setup should
2112 Note: You must still enable the drivers for GPIO and LED support
2113 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2115 Note: You have to set alix.force=1 for boards with Award BIOS.
2118 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2121 This option enables system support for the Soekris Engineering net5501.
2124 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2128 This option enables system support for the Traverse Technologies GEOS.
2134 depends on CPU_SUP_AMD && PCI
2136 source "drivers/pcmcia/Kconfig"
2138 source "drivers/pci/hotplug/Kconfig"
2141 bool "RapidIO support"
2145 If you say Y here, the kernel will include drivers and
2146 infrastructure code to support RapidIO interconnect devices.
2148 source "drivers/rapidio/Kconfig"
2153 menu "Executable file formats / Emulations"
2155 source "fs/Kconfig.binfmt"
2157 config IA32_EMULATION
2158 bool "IA32 Emulation"
2160 select COMPAT_BINFMT_ELF
2162 Include code to run legacy 32-bit programs under a
2163 64-bit kernel. You should likely turn this on, unless you're
2164 100% sure that you don't have any 32-bit programs left.
2167 tristate "IA32 a.out support"
2168 depends on IA32_EMULATION
2170 Support old a.out binaries in the 32bit emulation.
2173 bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
2174 depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
2176 Include code to run binaries for the x32 native 32-bit ABI
2177 for 64-bit processors. An x32 process gets access to the
2178 full 64-bit register file and wide data path while leaving
2179 pointers at 32 bits for smaller memory footprint.
2181 You will need a recent binutils (2.22 or later) with
2182 elf32_x86_64 support enabled to compile a kernel with this
2187 depends on IA32_EMULATION || X86_X32
2188 select ARCH_WANT_OLD_COMPAT_IPC
2190 config COMPAT_FOR_U64_ALIGNMENT
2194 config SYSVIPC_COMPAT
2196 depends on COMPAT && SYSVIPC
2200 depends on COMPAT && KEYS
2206 config HAVE_ATOMIC_IOMAP
2210 config HAVE_TEXT_POKE_SMP
2212 select STOP_MACHINE if SMP
2214 config X86_DEV_DMA_OPS
2216 depends on X86_64 || STA2X11
2218 config X86_DMA_REMAP
2222 source "net/Kconfig"
2224 source "drivers/Kconfig"
2226 source "drivers/firmware/Kconfig"
2230 source "arch/x86/Kconfig.debug"
2232 source "security/Kconfig"
2234 source "crypto/Kconfig"
2236 source "arch/x86/kvm/Kconfig"
2238 source "lib/Kconfig"