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
101 config INSTRUCTION_DECODER
102 def_bool (KPROBES || PERF_EVENTS || UPROBES)
106 default "elf32-i386" if X86_32
107 default "elf64-x86-64" if X86_64
109 config ARCH_DEFCONFIG
111 default "arch/x86/configs/i386_defconfig" if X86_32
112 default "arch/x86/configs/x86_64_defconfig" if X86_64
114 config LOCKDEP_SUPPORT
117 config STACKTRACE_SUPPORT
120 config HAVE_LATENCYTOP_SUPPORT
129 config NEED_DMA_MAP_STATE
130 def_bool (X86_64 || INTEL_IOMMU || DMA_API_DEBUG)
132 config NEED_SG_DMA_LENGTH
135 config GENERIC_ISA_DMA
141 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
143 config GENERIC_BUG_RELATIVE_POINTERS
146 config GENERIC_HWEIGHT
152 config ARCH_MAY_HAVE_PC_FDC
155 config RWSEM_GENERIC_SPINLOCK
158 config RWSEM_XCHGADD_ALGORITHM
161 config GENERIC_CALIBRATE_DELAY
164 config ARCH_HAS_CPU_RELAX
167 config ARCH_HAS_DEFAULT_IDLE
170 config ARCH_HAS_CACHE_LINE_SIZE
173 config ARCH_HAS_CPU_AUTOPROBE
176 config HAVE_SETUP_PER_CPU_AREA
179 config NEED_PER_CPU_EMBED_FIRST_CHUNK
182 config NEED_PER_CPU_PAGE_FIRST_CHUNK
185 config ARCH_HIBERNATION_POSSIBLE
188 config ARCH_SUSPEND_POSSIBLE
199 config ARCH_SUPPORTS_OPTIMIZED_INLINING
202 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
205 config HAVE_INTEL_TXT
207 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
211 depends on X86_32 && SMP
215 depends on X86_64 && SMP
221 config X86_32_LAZY_GS
223 depends on X86_32 && !CC_STACKPROTECTOR
225 config ARCH_HWEIGHT_CFLAGS
227 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
228 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
230 config ARCH_CPU_PROBE_RELEASE
232 depends on HOTPLUG_CPU
234 config ARCH_SUPPORTS_UPROBES
237 source "init/Kconfig"
238 source "kernel/Kconfig.freezer"
240 menu "Processor type and features"
243 bool "DMA memory allocation support" if EXPERT
246 DMA memory allocation support allows devices with less than 32-bit
247 addressing to allocate within the first 16MB of address space.
248 Disable if no such devices will be used.
253 bool "Symmetric multi-processing support"
255 This enables support for systems with more than one CPU. If you have
256 a system with only one CPU, like most personal computers, say N. If
257 you have a system with more than one CPU, say Y.
259 If you say N here, the kernel will run on single and multiprocessor
260 machines, but will use only one CPU of a multiprocessor machine. If
261 you say Y here, the kernel will run on many, but not all,
262 singleprocessor machines. On a singleprocessor machine, the kernel
263 will run faster if you say N here.
265 Note that if you say Y here and choose architecture "586" or
266 "Pentium" under "Processor family", the kernel will not work on 486
267 architectures. Similarly, multiprocessor kernels for the "PPro"
268 architecture may not work on all Pentium based boards.
270 People using multiprocessor machines who say Y here should also say
271 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
272 Management" code will be disabled if you say Y here.
274 See also <file:Documentation/x86/i386/IO-APIC.txt>,
275 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
276 <http://www.tldp.org/docs.html#howto>.
278 If you don't know what to do here, say N.
281 bool "Support x2apic"
282 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
284 This enables x2apic support on CPUs that have this feature.
286 This allows 32-bit apic IDs (so it can support very large systems),
287 and accesses the local apic via MSRs not via mmio.
289 If you don't know what to do here, say N.
292 bool "Enable MPS table" if ACPI
294 depends on X86_LOCAL_APIC
296 For old smp systems that do not have proper acpi support. Newer systems
297 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
300 bool "Support for big SMP systems with more than 8 CPUs"
301 depends on X86_32 && SMP
303 This option is needed for the systems that have more than 8 CPUs
306 config X86_EXTENDED_PLATFORM
307 bool "Support for extended (non-PC) x86 platforms"
310 If you disable this option then the kernel will only support
311 standard PC platforms. (which covers the vast majority of
314 If you enable this option then you'll be able to select support
315 for the following (non-PC) 32 bit x86 platforms:
319 SGI 320/540 (Visual Workstation)
320 STA2X11-based (e.g. Northville)
321 Summit/EXA (IBM x440)
322 Unisys ES7000 IA32 series
323 Moorestown MID devices
325 If you have one of these systems, or if you want to build a
326 generic distribution kernel, say Y here - otherwise say N.
330 config X86_EXTENDED_PLATFORM
331 bool "Support for extended (non-PC) x86 platforms"
334 If you disable this option then the kernel will only support
335 standard PC platforms. (which covers the vast majority of
338 If you enable this option then you'll be able to select support
339 for the following (non-PC) 64 bit x86 platforms:
344 If you have one of these systems, or if you want to build a
345 generic distribution kernel, say Y here - otherwise say N.
347 # This is an alphabetically sorted list of 64 bit extended platforms
348 # Please maintain the alphabetic order if and when there are additions
350 bool "Numascale NumaChip"
352 depends on X86_EXTENDED_PLATFORM
355 depends on X86_X2APIC
357 Adds support for Numascale NumaChip large-SMP systems. Needed to
358 enable more than ~168 cores.
359 If you don't have one of these, you should say N here.
363 select PARAVIRT_GUEST
365 depends on X86_64 && PCI
366 depends on X86_EXTENDED_PLATFORM
369 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
370 supposed to run on these EM64T-based machines. Only choose this option
371 if you have one of these machines.
374 bool "SGI Ultraviolet"
376 depends on X86_EXTENDED_PLATFORM
378 depends on X86_X2APIC
380 This option is needed in order to support SGI Ultraviolet systems.
381 If you don't have one of these, you should say N here.
383 # Following is an alphabetically sorted list of 32 bit extended platforms
384 # Please maintain the alphabetic order if and when there are additions
387 bool "CE4100 TV platform"
389 depends on PCI_GODIRECT
391 depends on X86_EXTENDED_PLATFORM
392 select X86_REBOOTFIXUPS
394 select OF_EARLY_FLATTREE
397 Select for the Intel CE media processor (CE4100) SOC.
398 This option compiles in support for the CE4100 SOC for settop
399 boxes and media devices.
401 config X86_WANT_INTEL_MID
402 bool "Intel MID platform support"
404 depends on X86_EXTENDED_PLATFORM
406 Select to build a kernel capable of supporting Intel MID platform
407 systems which do not have the PCI legacy interfaces (Moorestown,
408 Medfield). If you are building for a PC class system say N here.
410 if X86_WANT_INTEL_MID
416 bool "Medfield MID platform"
419 depends on X86_IO_APIC
427 select X86_PLATFORM_DEVICES
428 select MFD_INTEL_MSIC
430 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
431 Internet Device(MID) platform.
432 Unlike standard x86 PCs, Medfield does not have many legacy devices
433 nor standard legacy replacement devices/features. e.g. Medfield does
434 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
439 bool "RDC R-321x SoC"
441 depends on X86_EXTENDED_PLATFORM
443 select X86_REBOOTFIXUPS
445 This option is needed for RDC R-321x system-on-chip, also known
447 If you don't have one of these chips, you should say N here.
449 config X86_32_NON_STANDARD
450 bool "Support non-standard 32-bit SMP architectures"
451 depends on X86_32 && SMP
452 depends on X86_EXTENDED_PLATFORM
454 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
455 STA2X11, default subarchitectures. It is intended for a generic
456 binary kernel. If you select them all, kernel will probe it
457 one by one and will fallback to default.
459 # Alphabetically sorted list of Non standard 32 bit platforms
462 bool "NUMAQ (IBM/Sequent)"
463 depends on X86_32_NON_STANDARD
468 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
469 NUMA multiquad box. This changes the way that processors are
470 bootstrapped, and uses Clustered Logical APIC addressing mode instead
471 of Flat Logical. You will need a new lynxer.elf file to flash your
472 firmware with - send email to <Martin.Bligh@us.ibm.com>.
474 config X86_SUPPORTS_MEMORY_FAILURE
476 # MCE code calls memory_failure():
478 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
479 depends on !X86_NUMAQ
480 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
481 depends on X86_64 || !SPARSEMEM
482 select ARCH_SUPPORTS_MEMORY_FAILURE
485 bool "SGI 320/540 (Visual Workstation)"
486 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
487 depends on X86_32_NON_STANDARD
489 The SGI Visual Workstation series is an IA32-based workstation
490 based on SGI systems chips with some legacy PC hardware attached.
492 Say Y here to create a kernel to run on the SGI 320 or 540.
494 A kernel compiled for the Visual Workstation will run on general
495 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
498 bool "STA2X11 Companion Chip Support"
499 depends on X86_32_NON_STANDARD && PCI
500 select X86_DEV_DMA_OPS
504 select ARCH_REQUIRE_GPIOLIB
507 This adds support for boards based on the STA2X11 IO-Hub,
508 a.k.a. "ConneXt". The chip is used in place of the standard
509 PC chipset, so all "standard" peripherals are missing. If this
510 option is selected the kernel will still be able to boot on
511 standard PC machines.
514 bool "Summit/EXA (IBM x440)"
515 depends on X86_32_NON_STANDARD
517 This option is needed for IBM systems that use the Summit/EXA chipset.
518 In particular, it is needed for the x440.
521 bool "Unisys ES7000 IA32 series"
522 depends on X86_32_NON_STANDARD && X86_BIGSMP
524 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
525 supposed to run on an IA32-based Unisys ES7000 system.
528 tristate "Eurobraille/Iris poweroff module"
531 The Iris machines from EuroBraille do not have APM or ACPI support
532 to shut themselves down properly. A special I/O sequence is
533 needed to do so, which is what this module does at
536 This is only for Iris machines from EuroBraille.
540 config SCHED_OMIT_FRAME_POINTER
542 prompt "Single-depth WCHAN output"
545 Calculate simpler /proc/<PID>/wchan values. If this option
546 is disabled then wchan values will recurse back to the
547 caller function. This provides more accurate wchan values,
548 at the expense of slightly more scheduling overhead.
550 If in doubt, say "Y".
552 menuconfig PARAVIRT_GUEST
553 bool "Paravirtualized guest support"
555 Say Y here to get to see options related to running Linux under
556 various hypervisors. This option alone does not add any kernel code.
558 If you say N, all options in this submenu will be skipped and disabled.
562 config PARAVIRT_TIME_ACCOUNTING
563 bool "Paravirtual steal time accounting"
567 Select this option to enable fine granularity task steal time
568 accounting. Time spent executing other tasks in parallel with
569 the current vCPU is discounted from the vCPU power. To account for
570 that, there can be a small performance impact.
572 If in doubt, say N here.
574 source "arch/x86/xen/Kconfig"
577 bool "KVM paravirtualized clock"
579 select PARAVIRT_CLOCK
581 Turning on this option will allow you to run a paravirtualized clock
582 when running over the KVM hypervisor. Instead of relying on a PIT
583 (or probably other) emulation by the underlying device model, the host
584 provides the guest with timing infrastructure such as time of day, and
588 bool "KVM Guest support"
591 This option enables various optimizations for running under the KVM
594 source "arch/x86/lguest/Kconfig"
597 bool "Enable paravirtualization code"
599 This changes the kernel so it can modify itself when it is run
600 under a hypervisor, potentially improving performance significantly
601 over full virtualization. However, when run without a hypervisor
602 the kernel is theoretically slower and slightly larger.
604 config PARAVIRT_SPINLOCKS
605 bool "Paravirtualization layer for spinlocks"
606 depends on PARAVIRT && SMP && EXPERIMENTAL
608 Paravirtualized spinlocks allow a pvops backend to replace the
609 spinlock implementation with something virtualization-friendly
610 (for example, block the virtual CPU rather than spinning).
612 Unfortunately the downside is an up to 5% performance hit on
613 native kernels, with various workloads.
615 If you are unsure how to answer this question, answer N.
617 config PARAVIRT_CLOCK
622 config PARAVIRT_DEBUG
623 bool "paravirt-ops debugging"
624 depends on PARAVIRT && DEBUG_KERNEL
626 Enable to debug paravirt_ops internals. Specifically, BUG if
627 a paravirt_op is missing when it is called.
635 This option adds a kernel parameter 'memtest', which allows memtest
637 memtest=0, mean disabled; -- default
638 memtest=1, mean do 1 test pattern;
640 memtest=4, mean do 4 test patterns.
641 If you are unsure how to answer this question, answer N.
643 config X86_SUMMIT_NUMA
645 depends on X86_32 && NUMA && X86_32_NON_STANDARD
647 config X86_CYCLONE_TIMER
649 depends on X86_SUMMIT
651 source "arch/x86/Kconfig.cpu"
655 prompt "HPET Timer Support" if X86_32
657 Use the IA-PC HPET (High Precision Event Timer) to manage
658 time in preference to the PIT and RTC, if a HPET is
660 HPET is the next generation timer replacing legacy 8254s.
661 The HPET provides a stable time base on SMP
662 systems, unlike the TSC, but it is more expensive to access,
663 as it is off-chip. You can find the HPET spec at
664 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
666 You can safely choose Y here. However, HPET will only be
667 activated if the platform and the BIOS support this feature.
668 Otherwise the 8254 will be used for timing services.
670 Choose N to continue using the legacy 8254 timer.
672 config HPET_EMULATE_RTC
674 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
677 def_bool y if X86_INTEL_MID
678 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
680 depends on X86_INTEL_MID && SFI
682 APB timer is the replacement for 8254, HPET on X86 MID platforms.
683 The APBT provides a stable time base on SMP
684 systems, unlike the TSC, but it is more expensive to access,
685 as it is off-chip. APB timers are always running regardless of CPU
686 C states, they are used as per CPU clockevent device when possible.
688 # Mark as expert because too many people got it wrong.
689 # The code disables itself when not needed.
692 bool "Enable DMI scanning" if EXPERT
694 Enabled scanning of DMI to identify machine quirks. Say Y
695 here unless you have verified that your setup is not
696 affected by entries in the DMI blacklist. Required by PNP
700 bool "GART IOMMU support" if EXPERT
703 depends on X86_64 && PCI && AMD_NB
705 Support for full DMA access of devices with 32bit memory access only
706 on systems with more than 3GB. This is usually needed for USB,
707 sound, many IDE/SATA chipsets and some other devices.
708 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
709 based hardware IOMMU and a software bounce buffer based IOMMU used
710 on Intel systems and as fallback.
711 The code is only active when needed (enough memory and limited
712 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
716 bool "IBM Calgary IOMMU support"
718 depends on X86_64 && PCI && EXPERIMENTAL
720 Support for hardware IOMMUs in IBM's xSeries x366 and x460
721 systems. Needed to run systems with more than 3GB of memory
722 properly with 32-bit PCI devices that do not support DAC
723 (Double Address Cycle). Calgary also supports bus level
724 isolation, where all DMAs pass through the IOMMU. This
725 prevents them from going anywhere except their intended
726 destination. This catches hard-to-find kernel bugs and
727 mis-behaving drivers and devices that do not use the DMA-API
728 properly to set up their DMA buffers. The IOMMU can be
729 turned off at boot time with the iommu=off parameter.
730 Normally the kernel will make the right choice by itself.
733 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
735 prompt "Should Calgary be enabled by default?"
736 depends on CALGARY_IOMMU
738 Should Calgary be enabled by default? if you choose 'y', Calgary
739 will be used (if it exists). If you choose 'n', Calgary will not be
740 used even if it exists. If you choose 'n' and would like to use
741 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
744 # need this always selected by IOMMU for the VIA workaround
748 Support for software bounce buffers used on x86-64 systems
749 which don't have a hardware IOMMU (e.g. the current generation
750 of Intel's x86-64 CPUs). Using this PCI devices which can only
751 access 32-bits of memory can be used on systems with more than
752 3 GB of memory. If unsure, say Y.
755 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
758 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
759 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
760 select CPUMASK_OFFSTACK
762 Enable maximum number of CPUS and NUMA Nodes for this architecture.
766 int "Maximum number of CPUs" if SMP && !MAXSMP
767 range 2 8 if SMP && X86_32 && !X86_BIGSMP
768 range 2 512 if SMP && !MAXSMP
770 default "4096" if MAXSMP
771 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
774 This allows you to specify the maximum number of CPUs which this
775 kernel will support. The maximum supported value is 512 and the
776 minimum value which makes sense is 2.
778 This is purely to save memory - each supported CPU adds
779 approximately eight kilobytes to the kernel image.
782 bool "SMT (Hyperthreading) scheduler support"
785 SMT scheduler support improves the CPU scheduler's decision making
786 when dealing with Intel Pentium 4 chips with HyperThreading at a
787 cost of slightly increased overhead in some places. If unsure say
792 prompt "Multi-core scheduler support"
795 Multi-core scheduler support improves the CPU scheduler's decision
796 making when dealing with multi-core CPU chips at a cost of slightly
797 increased overhead in some places. If unsure say N here.
799 config IRQ_TIME_ACCOUNTING
800 bool "Fine granularity task level IRQ time accounting"
803 Select this option to enable fine granularity task irq time
804 accounting. This is done by reading a timestamp on each
805 transitions between softirq and hardirq state, so there can be a
806 small performance impact.
808 If in doubt, say N here.
810 source "kernel/Kconfig.preempt"
813 bool "Local APIC support on uniprocessors"
814 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
816 A local APIC (Advanced Programmable Interrupt Controller) is an
817 integrated interrupt controller in the CPU. If you have a single-CPU
818 system which has a processor with a local APIC, you can say Y here to
819 enable and use it. If you say Y here even though your machine doesn't
820 have a local APIC, then the kernel will still run with no slowdown at
821 all. The local APIC supports CPU-generated self-interrupts (timer,
822 performance counters), and the NMI watchdog which detects hard
826 bool "IO-APIC support on uniprocessors"
827 depends on X86_UP_APIC
829 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
830 SMP-capable replacement for PC-style interrupt controllers. Most
831 SMP systems and many recent uniprocessor systems have one.
833 If you have a single-CPU system with an IO-APIC, you can say Y here
834 to use it. If you say Y here even though your machine doesn't have
835 an IO-APIC, then the kernel will still run with no slowdown at all.
837 config X86_LOCAL_APIC
839 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
843 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
845 config X86_VISWS_APIC
847 depends on X86_32 && X86_VISWS
849 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
850 bool "Reroute for broken boot IRQs"
851 depends on X86_IO_APIC
853 This option enables a workaround that fixes a source of
854 spurious interrupts. This is recommended when threaded
855 interrupt handling is used on systems where the generation of
856 superfluous "boot interrupts" cannot be disabled.
858 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
859 entry in the chipset's IO-APIC is masked (as, e.g. the RT
860 kernel does during interrupt handling). On chipsets where this
861 boot IRQ generation cannot be disabled, this workaround keeps
862 the original IRQ line masked so that only the equivalent "boot
863 IRQ" is delivered to the CPUs. The workaround also tells the
864 kernel to set up the IRQ handler on the boot IRQ line. In this
865 way only one interrupt is delivered to the kernel. Otherwise
866 the spurious second interrupt may cause the kernel to bring
867 down (vital) interrupt lines.
869 Only affects "broken" chipsets. Interrupt sharing may be
870 increased on these systems.
873 bool "Machine Check / overheating reporting"
875 Machine Check support allows the processor to notify the
876 kernel if it detects a problem (e.g. overheating, data corruption).
877 The action the kernel takes depends on the severity of the problem,
878 ranging from warning messages to halting the machine.
882 prompt "Intel MCE features"
883 depends on X86_MCE && X86_LOCAL_APIC
885 Additional support for intel specific MCE features such as
890 prompt "AMD MCE features"
891 depends on X86_MCE && X86_LOCAL_APIC
893 Additional support for AMD specific MCE features such as
894 the DRAM Error Threshold.
896 config X86_ANCIENT_MCE
897 bool "Support for old Pentium 5 / WinChip machine checks"
898 depends on X86_32 && X86_MCE
900 Include support for machine check handling on old Pentium 5 or WinChip
901 systems. These typically need to be enabled explicitely on the command
904 config X86_MCE_THRESHOLD
905 depends on X86_MCE_AMD || X86_MCE_INTEL
908 config X86_MCE_INJECT
910 tristate "Machine check injector support"
912 Provide support for injecting machine checks for testing purposes.
913 If you don't know what a machine check is and you don't do kernel
914 QA it is safe to say n.
916 config X86_THERMAL_VECTOR
918 depends on X86_MCE_INTEL
921 bool "Enable VM86 support" if EXPERT
925 This option is required by programs like DOSEMU to run 16-bit legacy
926 code on X86 processors. It also may be needed by software like
927 XFree86 to initialize some video cards via BIOS. Disabling this
928 option saves about 6k.
931 tristate "Toshiba Laptop support"
934 This adds a driver to safely access the System Management Mode of
935 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
936 not work on models with a Phoenix BIOS. The System Management Mode
937 is used to set the BIOS and power saving options on Toshiba portables.
939 For information on utilities to make use of this driver see the
940 Toshiba Linux utilities web site at:
941 <http://www.buzzard.org.uk/toshiba/>.
943 Say Y if you intend to run this kernel on a Toshiba portable.
947 tristate "Dell laptop support"
950 This adds a driver to safely access the System Management Mode
951 of the CPU on the Dell Inspiron 8000. The System Management Mode
952 is used to read cpu temperature and cooling fan status and to
953 control the fans on the I8K portables.
955 This driver has been tested only on the Inspiron 8000 but it may
956 also work with other Dell laptops. You can force loading on other
957 models by passing the parameter `force=1' to the module. Use at
960 For information on utilities to make use of this driver see the
961 I8K Linux utilities web site at:
962 <http://people.debian.org/~dz/i8k/>
964 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
967 config X86_REBOOTFIXUPS
968 bool "Enable X86 board specific fixups for reboot"
971 This enables chipset and/or board specific fixups to be done
972 in order to get reboot to work correctly. This is only needed on
973 some combinations of hardware and BIOS. The symptom, for which
974 this config is intended, is when reboot ends with a stalled/hung
977 Currently, the only fixup is for the Geode machines using
978 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
980 Say Y if you want to enable the fixup. Currently, it's safe to
981 enable this option even if you don't need it.
985 tristate "/dev/cpu/microcode - microcode support"
988 If you say Y here, you will be able to update the microcode on
989 certain Intel and AMD processors. The Intel support is for the
990 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
991 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
992 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
993 You will obviously need the actual microcode binary data itself
994 which is not shipped with the Linux kernel.
996 This option selects the general module only, you need to select
997 at least one vendor specific module as well.
999 To compile this driver as a module, choose M here: the
1000 module will be called microcode.
1002 config MICROCODE_INTEL
1003 bool "Intel microcode patch loading support"
1004 depends on MICROCODE
1008 This options enables microcode patch loading support for Intel
1011 For latest news and information on obtaining all the required
1012 Intel ingredients for this driver, check:
1013 <http://www.urbanmyth.org/microcode/>.
1015 config MICROCODE_AMD
1016 bool "AMD microcode patch loading support"
1017 depends on MICROCODE
1020 If you select this option, microcode patch loading support for AMD
1021 processors will be enabled.
1023 config MICROCODE_OLD_INTERFACE
1025 depends on MICROCODE
1028 tristate "/dev/cpu/*/msr - Model-specific register support"
1030 This device gives privileged processes access to the x86
1031 Model-Specific Registers (MSRs). It is a character device with
1032 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1033 MSR accesses are directed to a specific CPU on multi-processor
1037 tristate "/dev/cpu/*/cpuid - CPU information support"
1039 This device gives processes access to the x86 CPUID instruction to
1040 be executed on a specific processor. It is a character device
1041 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1045 prompt "High Memory Support"
1046 default HIGHMEM64G if X86_NUMAQ
1052 depends on !X86_NUMAQ
1054 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1055 However, the address space of 32-bit x86 processors is only 4
1056 Gigabytes large. That means that, if you have a large amount of
1057 physical memory, not all of it can be "permanently mapped" by the
1058 kernel. The physical memory that's not permanently mapped is called
1061 If you are compiling a kernel which will never run on a machine with
1062 more than 1 Gigabyte total physical RAM, answer "off" here (default
1063 choice and suitable for most users). This will result in a "3GB/1GB"
1064 split: 3GB are mapped so that each process sees a 3GB virtual memory
1065 space and the remaining part of the 4GB virtual memory space is used
1066 by the kernel to permanently map as much physical memory as
1069 If the machine has between 1 and 4 Gigabytes physical RAM, then
1072 If more than 4 Gigabytes is used then answer "64GB" here. This
1073 selection turns Intel PAE (Physical Address Extension) mode on.
1074 PAE implements 3-level paging on IA32 processors. PAE is fully
1075 supported by Linux, PAE mode is implemented on all recent Intel
1076 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1077 then the kernel will not boot on CPUs that don't support PAE!
1079 The actual amount of total physical memory will either be
1080 auto detected or can be forced by using a kernel command line option
1081 such as "mem=256M". (Try "man bootparam" or see the documentation of
1082 your boot loader (lilo or loadlin) about how to pass options to the
1083 kernel at boot time.)
1085 If unsure, say "off".
1089 depends on !X86_NUMAQ
1091 Select this if you have a 32-bit processor and between 1 and 4
1092 gigabytes of physical RAM.
1096 depends on !M386 && !M486
1099 Select this if you have a 32-bit processor and more than 4
1100 gigabytes of physical RAM.
1105 depends on EXPERIMENTAL
1106 prompt "Memory split" if EXPERT
1110 Select the desired split between kernel and user memory.
1112 If the address range available to the kernel is less than the
1113 physical memory installed, the remaining memory will be available
1114 as "high memory". Accessing high memory is a little more costly
1115 than low memory, as it needs to be mapped into the kernel first.
1116 Note that increasing the kernel address space limits the range
1117 available to user programs, making the address space there
1118 tighter. Selecting anything other than the default 3G/1G split
1119 will also likely make your kernel incompatible with binary-only
1122 If you are not absolutely sure what you are doing, leave this
1126 bool "3G/1G user/kernel split"
1127 config VMSPLIT_3G_OPT
1129 bool "3G/1G user/kernel split (for full 1G low memory)"
1131 bool "2G/2G user/kernel split"
1132 config VMSPLIT_2G_OPT
1134 bool "2G/2G user/kernel split (for full 2G low memory)"
1136 bool "1G/3G user/kernel split"
1141 default 0xB0000000 if VMSPLIT_3G_OPT
1142 default 0x80000000 if VMSPLIT_2G
1143 default 0x78000000 if VMSPLIT_2G_OPT
1144 default 0x40000000 if VMSPLIT_1G
1150 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1153 bool "PAE (Physical Address Extension) Support"
1154 depends on X86_32 && !HIGHMEM4G
1156 PAE is required for NX support, and furthermore enables
1157 larger swapspace support for non-overcommit purposes. It
1158 has the cost of more pagetable lookup overhead, and also
1159 consumes more pagetable space per process.
1161 config ARCH_PHYS_ADDR_T_64BIT
1162 def_bool X86_64 || X86_PAE
1164 config ARCH_DMA_ADDR_T_64BIT
1165 def_bool X86_64 || HIGHMEM64G
1167 config DIRECT_GBPAGES
1168 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1172 Allow the kernel linear mapping to use 1GB pages on CPUs that
1173 support it. This can improve the kernel's performance a tiny bit by
1174 reducing TLB pressure. If in doubt, say "Y".
1176 # Common NUMA Features
1178 bool "Numa Memory Allocation and Scheduler Support"
1180 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1181 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1183 Enable NUMA (Non Uniform Memory Access) support.
1185 The kernel will try to allocate memory used by a CPU on the
1186 local memory controller of the CPU and add some more
1187 NUMA awareness to the kernel.
1189 For 64-bit this is recommended if the system is Intel Core i7
1190 (or later), AMD Opteron, or EM64T NUMA.
1192 For 32-bit this is only needed on (rare) 32-bit-only platforms
1193 that support NUMA topologies, such as NUMAQ / Summit, or if you
1194 boot a 32-bit kernel on a 64-bit NUMA platform.
1196 Otherwise, you should say N.
1198 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1199 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1203 prompt "Old style AMD Opteron NUMA detection"
1204 depends on X86_64 && NUMA && PCI
1206 Enable AMD NUMA node topology detection. You should say Y here if
1207 you have a multi processor AMD system. This uses an old method to
1208 read the NUMA configuration directly from the builtin Northbridge
1209 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1210 which also takes priority if both are compiled in.
1212 config X86_64_ACPI_NUMA
1214 prompt "ACPI NUMA detection"
1215 depends on X86_64 && NUMA && ACPI && PCI
1218 Enable ACPI SRAT based node topology detection.
1220 # Some NUMA nodes have memory ranges that span
1221 # other nodes. Even though a pfn is valid and
1222 # between a node's start and end pfns, it may not
1223 # reside on that node. See memmap_init_zone()
1225 config NODES_SPAN_OTHER_NODES
1227 depends on X86_64_ACPI_NUMA
1230 bool "NUMA emulation"
1233 Enable NUMA emulation. A flat machine will be split
1234 into virtual nodes when booted with "numa=fake=N", where N is the
1235 number of nodes. This is only useful for debugging.
1238 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1240 default "10" if MAXSMP
1241 default "6" if X86_64
1242 default "4" if X86_NUMAQ
1244 depends on NEED_MULTIPLE_NODES
1246 Specify the maximum number of NUMA Nodes available on the target
1247 system. Increases memory reserved to accommodate various tables.
1249 config HAVE_ARCH_ALLOC_REMAP
1251 depends on X86_32 && NUMA
1253 config ARCH_HAVE_MEMORY_PRESENT
1255 depends on X86_32 && DISCONTIGMEM
1257 config NEED_NODE_MEMMAP_SIZE
1259 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1261 config ARCH_FLATMEM_ENABLE
1263 depends on X86_32 && !NUMA
1265 config ARCH_DISCONTIGMEM_ENABLE
1267 depends on NUMA && X86_32
1269 config ARCH_DISCONTIGMEM_DEFAULT
1271 depends on NUMA && X86_32
1273 config ARCH_SPARSEMEM_ENABLE
1275 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1276 select SPARSEMEM_STATIC if X86_32
1277 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1279 config ARCH_SPARSEMEM_DEFAULT
1283 config ARCH_SELECT_MEMORY_MODEL
1285 depends on ARCH_SPARSEMEM_ENABLE
1287 config ARCH_MEMORY_PROBE
1289 depends on MEMORY_HOTPLUG
1291 config ARCH_PROC_KCORE_TEXT
1293 depends on X86_64 && PROC_KCORE
1295 config ILLEGAL_POINTER_VALUE
1298 default 0xdead000000000000 if X86_64
1303 bool "Allocate 3rd-level pagetables from highmem"
1306 The VM uses one page table entry for each page of physical memory.
1307 For systems with a lot of RAM, this can be wasteful of precious
1308 low memory. Setting this option will put user-space page table
1309 entries in high memory.
1311 config X86_CHECK_BIOS_CORRUPTION
1312 bool "Check for low memory corruption"
1314 Periodically check for memory corruption in low memory, which
1315 is suspected to be caused by BIOS. Even when enabled in the
1316 configuration, it is disabled at runtime. Enable it by
1317 setting "memory_corruption_check=1" on the kernel command
1318 line. By default it scans the low 64k of memory every 60
1319 seconds; see the memory_corruption_check_size and
1320 memory_corruption_check_period parameters in
1321 Documentation/kernel-parameters.txt to adjust this.
1323 When enabled with the default parameters, this option has
1324 almost no overhead, as it reserves a relatively small amount
1325 of memory and scans it infrequently. It both detects corruption
1326 and prevents it from affecting the running system.
1328 It is, however, intended as a diagnostic tool; if repeatable
1329 BIOS-originated corruption always affects the same memory,
1330 you can use memmap= to prevent the kernel from using that
1333 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1334 bool "Set the default setting of memory_corruption_check"
1335 depends on X86_CHECK_BIOS_CORRUPTION
1338 Set whether the default state of memory_corruption_check is
1341 config X86_RESERVE_LOW
1342 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1346 Specify the amount of low memory to reserve for the BIOS.
1348 The first page contains BIOS data structures that the kernel
1349 must not use, so that page must always be reserved.
1351 By default we reserve the first 64K of physical RAM, as a
1352 number of BIOSes are known to corrupt that memory range
1353 during events such as suspend/resume or monitor cable
1354 insertion, so it must not be used by the kernel.
1356 You can set this to 4 if you are absolutely sure that you
1357 trust the BIOS to get all its memory reservations and usages
1358 right. If you know your BIOS have problems beyond the
1359 default 64K area, you can set this to 640 to avoid using the
1360 entire low memory range.
1362 If you have doubts about the BIOS (e.g. suspend/resume does
1363 not work or there's kernel crashes after certain hardware
1364 hotplug events) then you might want to enable
1365 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1366 typical corruption patterns.
1368 Leave this to the default value of 64 if you are unsure.
1370 config MATH_EMULATION
1372 prompt "Math emulation" if X86_32
1374 Linux can emulate a math coprocessor (used for floating point
1375 operations) if you don't have one. 486DX and Pentium processors have
1376 a math coprocessor built in, 486SX and 386 do not, unless you added
1377 a 487DX or 387, respectively. (The messages during boot time can
1378 give you some hints here ["man dmesg"].) Everyone needs either a
1379 coprocessor or this emulation.
1381 If you don't have a math coprocessor, you need to say Y here; if you
1382 say Y here even though you have a coprocessor, the coprocessor will
1383 be used nevertheless. (This behavior can be changed with the kernel
1384 command line option "no387", which comes handy if your coprocessor
1385 is broken. Try "man bootparam" or see the documentation of your boot
1386 loader (lilo or loadlin) about how to pass options to the kernel at
1387 boot time.) This means that it is a good idea to say Y here if you
1388 intend to use this kernel on different machines.
1390 More information about the internals of the Linux math coprocessor
1391 emulation can be found in <file:arch/x86/math-emu/README>.
1393 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1394 kernel, it won't hurt.
1398 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1400 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1401 the Memory Type Range Registers (MTRRs) may be used to control
1402 processor access to memory ranges. This is most useful if you have
1403 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1404 allows bus write transfers to be combined into a larger transfer
1405 before bursting over the PCI/AGP bus. This can increase performance
1406 of image write operations 2.5 times or more. Saying Y here creates a
1407 /proc/mtrr file which may be used to manipulate your processor's
1408 MTRRs. Typically the X server should use this.
1410 This code has a reasonably generic interface so that similar
1411 control registers on other processors can be easily supported
1414 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1415 Registers (ARRs) which provide a similar functionality to MTRRs. For
1416 these, the ARRs are used to emulate the MTRRs.
1417 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1418 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1419 write-combining. All of these processors are supported by this code
1420 and it makes sense to say Y here if you have one of them.
1422 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1423 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1424 can lead to all sorts of problems, so it's good to say Y here.
1426 You can safely say Y even if your machine doesn't have MTRRs, you'll
1427 just add about 9 KB to your kernel.
1429 See <file:Documentation/x86/mtrr.txt> for more information.
1431 config MTRR_SANITIZER
1433 prompt "MTRR cleanup support"
1436 Convert MTRR layout from continuous to discrete, so X drivers can
1437 add writeback entries.
1439 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1440 The largest mtrr entry size for a continuous block can be set with
1445 config MTRR_SANITIZER_ENABLE_DEFAULT
1446 int "MTRR cleanup enable value (0-1)"
1449 depends on MTRR_SANITIZER
1451 Enable mtrr cleanup default value
1453 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1454 int "MTRR cleanup spare reg num (0-7)"
1457 depends on MTRR_SANITIZER
1459 mtrr cleanup spare entries default, it can be changed via
1460 mtrr_spare_reg_nr=N on the kernel command line.
1464 prompt "x86 PAT support" if EXPERT
1467 Use PAT attributes to setup page level cache control.
1469 PATs are the modern equivalents of MTRRs and are much more
1470 flexible than MTRRs.
1472 Say N here if you see bootup problems (boot crash, boot hang,
1473 spontaneous reboots) or a non-working video driver.
1477 config ARCH_USES_PG_UNCACHED
1483 prompt "x86 architectural random number generator" if EXPERT
1485 Enable the x86 architectural RDRAND instruction
1486 (Intel Bull Mountain technology) to generate random numbers.
1487 If supported, this is a high bandwidth, cryptographically
1488 secure hardware random number generator.
1491 bool "EFI runtime service support"
1494 This enables the kernel to use EFI runtime services that are
1495 available (such as the EFI variable services).
1497 This option is only useful on systems that have EFI firmware.
1498 In addition, you should use the latest ELILO loader available
1499 at <http://elilo.sourceforge.net> in order to take advantage
1500 of EFI runtime services. However, even with this option, the
1501 resultant kernel should continue to boot on existing non-EFI
1505 bool "EFI stub support"
1508 This kernel feature allows a bzImage to be loaded directly
1509 by EFI firmware without the use of a bootloader.
1511 See Documentation/x86/efi-stub.txt for more information.
1515 prompt "Enable seccomp to safely compute untrusted bytecode"
1517 This kernel feature is useful for number crunching applications
1518 that may need to compute untrusted bytecode during their
1519 execution. By using pipes or other transports made available to
1520 the process as file descriptors supporting the read/write
1521 syscalls, it's possible to isolate those applications in
1522 their own address space using seccomp. Once seccomp is
1523 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1524 and the task is only allowed to execute a few safe syscalls
1525 defined by each seccomp mode.
1527 If unsure, say Y. Only embedded should say N here.
1529 config CC_STACKPROTECTOR
1530 bool "Enable -fstack-protector buffer overflow detection"
1532 This option turns on the -fstack-protector GCC feature. This
1533 feature puts, at the beginning of functions, a canary value on
1534 the stack just before the return address, and validates
1535 the value just before actually returning. Stack based buffer
1536 overflows (that need to overwrite this return address) now also
1537 overwrite the canary, which gets detected and the attack is then
1538 neutralized via a kernel panic.
1540 This feature requires gcc version 4.2 or above, or a distribution
1541 gcc with the feature backported. Older versions are automatically
1542 detected and for those versions, this configuration option is
1543 ignored. (and a warning is printed during bootup)
1545 source kernel/Kconfig.hz
1548 bool "kexec system call"
1550 kexec is a system call that implements the ability to shutdown your
1551 current kernel, and to start another kernel. It is like a reboot
1552 but it is independent of the system firmware. And like a reboot
1553 you can start any kernel with it, not just Linux.
1555 The name comes from the similarity to the exec system call.
1557 It is an ongoing process to be certain the hardware in a machine
1558 is properly shutdown, so do not be surprised if this code does not
1559 initially work for you. It may help to enable device hotplugging
1560 support. As of this writing the exact hardware interface is
1561 strongly in flux, so no good recommendation can be made.
1564 bool "kernel crash dumps"
1565 depends on X86_64 || (X86_32 && HIGHMEM)
1567 Generate crash dump after being started by kexec.
1568 This should be normally only set in special crash dump kernels
1569 which are loaded in the main kernel with kexec-tools into
1570 a specially reserved region and then later executed after
1571 a crash by kdump/kexec. The crash dump kernel must be compiled
1572 to a memory address not used by the main kernel or BIOS using
1573 PHYSICAL_START, or it must be built as a relocatable image
1574 (CONFIG_RELOCATABLE=y).
1575 For more details see Documentation/kdump/kdump.txt
1578 bool "kexec jump (EXPERIMENTAL)"
1579 depends on EXPERIMENTAL
1580 depends on KEXEC && HIBERNATION
1582 Jump between original kernel and kexeced kernel and invoke
1583 code in physical address mode via KEXEC
1585 config PHYSICAL_START
1586 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1589 This gives the physical address where the kernel is loaded.
1591 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1592 bzImage will decompress itself to above physical address and
1593 run from there. Otherwise, bzImage will run from the address where
1594 it has been loaded by the boot loader and will ignore above physical
1597 In normal kdump cases one does not have to set/change this option
1598 as now bzImage can be compiled as a completely relocatable image
1599 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1600 address. This option is mainly useful for the folks who don't want
1601 to use a bzImage for capturing the crash dump and want to use a
1602 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1603 to be specifically compiled to run from a specific memory area
1604 (normally a reserved region) and this option comes handy.
1606 So if you are using bzImage for capturing the crash dump,
1607 leave the value here unchanged to 0x1000000 and set
1608 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1609 for capturing the crash dump change this value to start of
1610 the reserved region. In other words, it can be set based on
1611 the "X" value as specified in the "crashkernel=YM@XM"
1612 command line boot parameter passed to the panic-ed
1613 kernel. Please take a look at Documentation/kdump/kdump.txt
1614 for more details about crash dumps.
1616 Usage of bzImage for capturing the crash dump is recommended as
1617 one does not have to build two kernels. Same kernel can be used
1618 as production kernel and capture kernel. Above option should have
1619 gone away after relocatable bzImage support is introduced. But it
1620 is present because there are users out there who continue to use
1621 vmlinux for dump capture. This option should go away down the
1624 Don't change this unless you know what you are doing.
1627 bool "Build a relocatable kernel"
1630 This builds a kernel image that retains relocation information
1631 so it can be loaded someplace besides the default 1MB.
1632 The relocations tend to make the kernel binary about 10% larger,
1633 but are discarded at runtime.
1635 One use is for the kexec on panic case where the recovery kernel
1636 must live at a different physical address than the primary
1639 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1640 it has been loaded at and the compile time physical address
1641 (CONFIG_PHYSICAL_START) is ignored.
1643 # Relocation on x86-32 needs some additional build support
1644 config X86_NEED_RELOCS
1646 depends on X86_32 && RELOCATABLE
1648 config PHYSICAL_ALIGN
1649 hex "Alignment value to which kernel should be aligned" if X86_32
1651 range 0x2000 0x1000000
1653 This value puts the alignment restrictions on physical address
1654 where kernel is loaded and run from. Kernel is compiled for an
1655 address which meets above alignment restriction.
1657 If bootloader loads the kernel at a non-aligned address and
1658 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1659 address aligned to above value and run from there.
1661 If bootloader loads the kernel at a non-aligned address and
1662 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1663 load address and decompress itself to the address it has been
1664 compiled for and run from there. The address for which kernel is
1665 compiled already meets above alignment restrictions. Hence the
1666 end result is that kernel runs from a physical address meeting
1667 above alignment restrictions.
1669 Don't change this unless you know what you are doing.
1672 bool "Support for hot-pluggable CPUs"
1673 depends on SMP && HOTPLUG
1675 Say Y here to allow turning CPUs off and on. CPUs can be
1676 controlled through /sys/devices/system/cpu.
1677 ( Note: power management support will enable this option
1678 automatically on SMP systems. )
1679 Say N if you want to disable CPU hotplug.
1683 prompt "Compat VDSO support"
1684 depends on X86_32 || IA32_EMULATION
1686 Map the 32-bit VDSO to the predictable old-style address too.
1688 Say N here if you are running a sufficiently recent glibc
1689 version (2.3.3 or later), to remove the high-mapped
1690 VDSO mapping and to exclusively use the randomized VDSO.
1695 bool "Built-in kernel command line"
1697 Allow for specifying boot arguments to the kernel at
1698 build time. On some systems (e.g. embedded ones), it is
1699 necessary or convenient to provide some or all of the
1700 kernel boot arguments with the kernel itself (that is,
1701 to not rely on the boot loader to provide them.)
1703 To compile command line arguments into the kernel,
1704 set this option to 'Y', then fill in the
1705 the boot arguments in CONFIG_CMDLINE.
1707 Systems with fully functional boot loaders (i.e. non-embedded)
1708 should leave this option set to 'N'.
1711 string "Built-in kernel command string"
1712 depends on CMDLINE_BOOL
1715 Enter arguments here that should be compiled into the kernel
1716 image and used at boot time. If the boot loader provides a
1717 command line at boot time, it is appended to this string to
1718 form the full kernel command line, when the system boots.
1720 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1721 change this behavior.
1723 In most cases, the command line (whether built-in or provided
1724 by the boot loader) should specify the device for the root
1727 config CMDLINE_OVERRIDE
1728 bool "Built-in command line overrides boot loader arguments"
1729 depends on CMDLINE_BOOL
1731 Set this option to 'Y' to have the kernel ignore the boot loader
1732 command line, and use ONLY the built-in command line.
1734 This is used to work around broken boot loaders. This should
1735 be set to 'N' under normal conditions.
1739 config ARCH_ENABLE_MEMORY_HOTPLUG
1741 depends on X86_64 || (X86_32 && HIGHMEM)
1743 config ARCH_ENABLE_MEMORY_HOTREMOVE
1745 depends on MEMORY_HOTPLUG
1747 config USE_PERCPU_NUMA_NODE_ID
1751 menu "Power management and ACPI options"
1753 config ARCH_HIBERNATION_HEADER
1755 depends on X86_64 && HIBERNATION
1757 source "kernel/power/Kconfig"
1759 source "drivers/acpi/Kconfig"
1761 source "drivers/sfi/Kconfig"
1768 tristate "APM (Advanced Power Management) BIOS support"
1769 depends on X86_32 && PM_SLEEP
1771 APM is a BIOS specification for saving power using several different
1772 techniques. This is mostly useful for battery powered laptops with
1773 APM compliant BIOSes. If you say Y here, the system time will be
1774 reset after a RESUME operation, the /proc/apm device will provide
1775 battery status information, and user-space programs will receive
1776 notification of APM "events" (e.g. battery status change).
1778 If you select "Y" here, you can disable actual use of the APM
1779 BIOS by passing the "apm=off" option to the kernel at boot time.
1781 Note that the APM support is almost completely disabled for
1782 machines with more than one CPU.
1784 In order to use APM, you will need supporting software. For location
1785 and more information, read <file:Documentation/power/apm-acpi.txt>
1786 and the Battery Powered Linux mini-HOWTO, available from
1787 <http://www.tldp.org/docs.html#howto>.
1789 This driver does not spin down disk drives (see the hdparm(8)
1790 manpage ("man 8 hdparm") for that), and it doesn't turn off
1791 VESA-compliant "green" monitors.
1793 This driver does not support the TI 4000M TravelMate and the ACER
1794 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1795 desktop machines also don't have compliant BIOSes, and this driver
1796 may cause those machines to panic during the boot phase.
1798 Generally, if you don't have a battery in your machine, there isn't
1799 much point in using this driver and you should say N. If you get
1800 random kernel OOPSes or reboots that don't seem to be related to
1801 anything, try disabling/enabling this option (or disabling/enabling
1804 Some other things you should try when experiencing seemingly random,
1807 1) make sure that you have enough swap space and that it is
1809 2) pass the "no-hlt" option to the kernel
1810 3) switch on floating point emulation in the kernel and pass
1811 the "no387" option to the kernel
1812 4) pass the "floppy=nodma" option to the kernel
1813 5) pass the "mem=4M" option to the kernel (thereby disabling
1814 all but the first 4 MB of RAM)
1815 6) make sure that the CPU is not over clocked.
1816 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1817 8) disable the cache from your BIOS settings
1818 9) install a fan for the video card or exchange video RAM
1819 10) install a better fan for the CPU
1820 11) exchange RAM chips
1821 12) exchange the motherboard.
1823 To compile this driver as a module, choose M here: the
1824 module will be called apm.
1828 config APM_IGNORE_USER_SUSPEND
1829 bool "Ignore USER SUSPEND"
1831 This option will ignore USER SUSPEND requests. On machines with a
1832 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1833 series notebooks, it is necessary to say Y because of a BIOS bug.
1835 config APM_DO_ENABLE
1836 bool "Enable PM at boot time"
1838 Enable APM features at boot time. From page 36 of the APM BIOS
1839 specification: "When disabled, the APM BIOS does not automatically
1840 power manage devices, enter the Standby State, enter the Suspend
1841 State, or take power saving steps in response to CPU Idle calls."
1842 This driver will make CPU Idle calls when Linux is idle (unless this
1843 feature is turned off -- see "Do CPU IDLE calls", below). This
1844 should always save battery power, but more complicated APM features
1845 will be dependent on your BIOS implementation. You may need to turn
1846 this option off if your computer hangs at boot time when using APM
1847 support, or if it beeps continuously instead of suspending. Turn
1848 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1849 T400CDT. This is off by default since most machines do fine without
1853 bool "Make CPU Idle calls when idle"
1855 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1856 On some machines, this can activate improved power savings, such as
1857 a slowed CPU clock rate, when the machine is idle. These idle calls
1858 are made after the idle loop has run for some length of time (e.g.,
1859 333 mS). On some machines, this will cause a hang at boot time or
1860 whenever the CPU becomes idle. (On machines with more than one CPU,
1861 this option does nothing.)
1863 config APM_DISPLAY_BLANK
1864 bool "Enable console blanking using APM"
1866 Enable console blanking using the APM. Some laptops can use this to
1867 turn off the LCD backlight when the screen blanker of the Linux
1868 virtual console blanks the screen. Note that this is only used by
1869 the virtual console screen blanker, and won't turn off the backlight
1870 when using the X Window system. This also doesn't have anything to
1871 do with your VESA-compliant power-saving monitor. Further, this
1872 option doesn't work for all laptops -- it might not turn off your
1873 backlight at all, or it might print a lot of errors to the console,
1874 especially if you are using gpm.
1876 config APM_ALLOW_INTS
1877 bool "Allow interrupts during APM BIOS calls"
1879 Normally we disable external interrupts while we are making calls to
1880 the APM BIOS as a measure to lessen the effects of a badly behaving
1881 BIOS implementation. The BIOS should reenable interrupts if it
1882 needs to. Unfortunately, some BIOSes do not -- especially those in
1883 many of the newer IBM Thinkpads. If you experience hangs when you
1884 suspend, try setting this to Y. Otherwise, say N.
1888 source "drivers/cpufreq/Kconfig"
1890 source "drivers/cpuidle/Kconfig"
1892 source "drivers/idle/Kconfig"
1897 menu "Bus options (PCI etc.)"
1902 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1904 Find out whether you have a PCI motherboard. PCI is the name of a
1905 bus system, i.e. the way the CPU talks to the other stuff inside
1906 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1907 VESA. If you have PCI, say Y, otherwise N.
1910 prompt "PCI access mode"
1911 depends on X86_32 && PCI
1914 On PCI systems, the BIOS can be used to detect the PCI devices and
1915 determine their configuration. However, some old PCI motherboards
1916 have BIOS bugs and may crash if this is done. Also, some embedded
1917 PCI-based systems don't have any BIOS at all. Linux can also try to
1918 detect the PCI hardware directly without using the BIOS.
1920 With this option, you can specify how Linux should detect the
1921 PCI devices. If you choose "BIOS", the BIOS will be used,
1922 if you choose "Direct", the BIOS won't be used, and if you
1923 choose "MMConfig", then PCI Express MMCONFIG will be used.
1924 If you choose "Any", the kernel will try MMCONFIG, then the
1925 direct access method and falls back to the BIOS if that doesn't
1926 work. If unsure, go with the default, which is "Any".
1931 config PCI_GOMMCONFIG
1948 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1950 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1953 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
1957 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1961 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1965 depends on PCI && XEN
1973 bool "Support mmconfig PCI config space access"
1974 depends on X86_64 && PCI && ACPI
1976 config PCI_CNB20LE_QUIRK
1977 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1979 depends on PCI && EXPERIMENTAL
1981 Read the PCI windows out of the CNB20LE host bridge. This allows
1982 PCI hotplug to work on systems with the CNB20LE chipset which do
1985 There's no public spec for this chipset, and this functionality
1986 is known to be incomplete.
1988 You should say N unless you know you need this.
1990 source "drivers/pci/pcie/Kconfig"
1992 source "drivers/pci/Kconfig"
1994 # x86_64 have no ISA slots, but can have ISA-style DMA.
1996 bool "ISA-style DMA support" if (X86_64 && EXPERT)
1999 Enables ISA-style DMA support for devices requiring such controllers.
2007 Find out whether you have ISA slots on your motherboard. ISA is the
2008 name of a bus system, i.e. the way the CPU talks to the other stuff
2009 inside your box. Other bus systems are PCI, EISA, MicroChannel
2010 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2011 newer boards don't support it. If you have ISA, say Y, otherwise N.
2017 The Extended Industry Standard Architecture (EISA) bus was
2018 developed as an open alternative to the IBM MicroChannel bus.
2020 The EISA bus provided some of the features of the IBM MicroChannel
2021 bus while maintaining backward compatibility with cards made for
2022 the older ISA bus. The EISA bus saw limited use between 1988 and
2023 1995 when it was made obsolete by the PCI bus.
2025 Say Y here if you are building a kernel for an EISA-based machine.
2029 source "drivers/eisa/Kconfig"
2032 tristate "NatSemi SCx200 support"
2034 This provides basic support for National Semiconductor's
2035 (now AMD's) Geode processors. The driver probes for the
2036 PCI-IDs of several on-chip devices, so its a good dependency
2037 for other scx200_* drivers.
2039 If compiled as a module, the driver is named scx200.
2041 config SCx200HR_TIMER
2042 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2046 This driver provides a clocksource built upon the on-chip
2047 27MHz high-resolution timer. Its also a workaround for
2048 NSC Geode SC-1100's buggy TSC, which loses time when the
2049 processor goes idle (as is done by the scheduler). The
2050 other workaround is idle=poll boot option.
2053 bool "One Laptop Per Child support"
2060 Add support for detecting the unique features of the OLPC
2064 bool "OLPC XO-1 Power Management"
2065 depends on OLPC && MFD_CS5535 && PM_SLEEP
2068 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2071 bool "OLPC XO-1 Real Time Clock"
2072 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2074 Add support for the XO-1 real time clock, which can be used as a
2075 programmable wakeup source.
2078 bool "OLPC XO-1 SCI extras"
2079 depends on OLPC && OLPC_XO1_PM
2084 Add support for SCI-based features of the OLPC XO-1 laptop:
2085 - EC-driven system wakeups
2089 - AC adapter status updates
2090 - Battery status updates
2092 config OLPC_XO15_SCI
2093 bool "OLPC XO-1.5 SCI extras"
2094 depends on OLPC && ACPI
2097 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2098 - EC-driven system wakeups
2099 - AC adapter status updates
2100 - Battery status updates
2103 bool "PCEngines ALIX System Support (LED setup)"
2106 This option enables system support for the PCEngines ALIX.
2107 At present this just sets up LEDs for GPIO control on
2108 ALIX2/3/6 boards. However, other system specific setup should
2111 Note: You must still enable the drivers for GPIO and LED support
2112 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2114 Note: You have to set alix.force=1 for boards with Award BIOS.
2117 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2120 This option enables system support for the Soekris Engineering net5501.
2123 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2127 This option enables system support for the Traverse Technologies GEOS.
2133 depends on CPU_SUP_AMD && PCI
2135 source "drivers/pcmcia/Kconfig"
2137 source "drivers/pci/hotplug/Kconfig"
2140 bool "RapidIO support"
2144 If you say Y here, the kernel will include drivers and
2145 infrastructure code to support RapidIO interconnect devices.
2147 source "drivers/rapidio/Kconfig"
2152 menu "Executable file formats / Emulations"
2154 source "fs/Kconfig.binfmt"
2156 config IA32_EMULATION
2157 bool "IA32 Emulation"
2159 select COMPAT_BINFMT_ELF
2161 Include code to run legacy 32-bit programs under a
2162 64-bit kernel. You should likely turn this on, unless you're
2163 100% sure that you don't have any 32-bit programs left.
2166 tristate "IA32 a.out support"
2167 depends on IA32_EMULATION
2169 Support old a.out binaries in the 32bit emulation.
2172 bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
2173 depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
2175 Include code to run binaries for the x32 native 32-bit ABI
2176 for 64-bit processors. An x32 process gets access to the
2177 full 64-bit register file and wide data path while leaving
2178 pointers at 32 bits for smaller memory footprint.
2180 You will need a recent binutils (2.22 or later) with
2181 elf32_x86_64 support enabled to compile a kernel with this
2186 depends on IA32_EMULATION || X86_X32
2187 select ARCH_WANT_OLD_COMPAT_IPC
2189 config COMPAT_FOR_U64_ALIGNMENT
2193 config SYSVIPC_COMPAT
2195 depends on COMPAT && SYSVIPC
2199 depends on COMPAT && KEYS
2205 config HAVE_ATOMIC_IOMAP
2209 config HAVE_TEXT_POKE_SMP
2211 select STOP_MACHINE if SMP
2213 config X86_DEV_DMA_OPS
2215 depends on X86_64 || STA2X11
2217 config X86_DMA_REMAP
2221 source "net/Kconfig"
2223 source "drivers/Kconfig"
2225 source "drivers/firmware/Kconfig"
2229 source "arch/x86/Kconfig.debug"
2231 source "security/Kconfig"
2233 source "crypto/Kconfig"
2235 source "arch/x86/kvm/Kconfig"
2237 source "lib/Kconfig"