arch/x86/Kconfig

   1 # x86 configuration
   2 mainmenu "Linux Kernel Configuration for x86"
   3
   4 # Select 32 or 64 bit
   5 config 64BIT
   6         bool "64-bit kernel" if ARCH = "x86"
   7         default ARCH = "x86_64"
   8         ---help---
   9           Say yes to build a 64-bit kernel - formerly known as x86_64
  10           Say no to build a 32-bit kernel - formerly known as i386
  11
  12 config X86_32
  13         def_bool !64BIT
  14
  15 config X86_64
  16         def_bool 64BIT
  17
  18 ### Arch settings
  19 config X86
  20         def_bool y
  21         select HAVE_AOUT if X86_32
  22         select HAVE_READQ
  23         select HAVE_WRITEQ
  24         select HAVE_UNSTABLE_SCHED_CLOCK
  25         select HAVE_IDE
  26         select HAVE_OPROFILE
  27         select HAVE_IOREMAP_PROT
  28         select HAVE_KPROBES
  29         select ARCH_WANT_OPTIONAL_GPIOLIB
  30         select ARCH_WANT_FRAME_POINTERS
  31         select HAVE_KRETPROBES
  32         select HAVE_FTRACE_MCOUNT_RECORD
  33         select HAVE_DYNAMIC_FTRACE
  34         select HAVE_FUNCTION_TRACER
  35         select HAVE_FUNCTION_GRAPH_TRACER
  36         select HAVE_FUNCTION_TRACE_MCOUNT_TEST
  37         select HAVE_KVM
  38         select HAVE_ARCH_KGDB
  39         select HAVE_ARCH_TRACEHOOK
  40         select HAVE_GENERIC_DMA_COHERENT if X86_32
  41         select HAVE_EFFICIENT_UNALIGNED_ACCESS
  42         select USER_STACKTRACE_SUPPORT
  43
  44 config ARCH_DEFCONFIG
  45         string
  46         default "arch/x86/configs/i386_defconfig" if X86_32
  47         default "arch/x86/configs/x86_64_defconfig" if X86_64
  48
  49 config GENERIC_TIME
  50         def_bool y
  51
  52 config GENERIC_CMOS_UPDATE
  53         def_bool y
  54
  55 config CLOCKSOURCE_WATCHDOG
  56         def_bool y
  57
  58 config GENERIC_CLOCKEVENTS
  59         def_bool y
  60
  61 config GENERIC_CLOCKEVENTS_BROADCAST
  62         def_bool y
  63         depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
  64
  65 config LOCKDEP_SUPPORT
  66         def_bool y
  67
  68 config STACKTRACE_SUPPORT
  69         def_bool y
  70
  71 config HAVE_LATENCYTOP_SUPPORT
  72         def_bool y
  73
  74 config FAST_CMPXCHG_LOCAL
  75         bool
  76         default y
  77
  78 config MMU
  79         def_bool y
  80
  81 config ZONE_DMA
  82         def_bool y
  83
  84 config SBUS
  85         bool
  86
  87 config GENERIC_ISA_DMA
  88         def_bool y
  89
  90 config GENERIC_IOMAP
  91         def_bool y
  92
  93 config GENERIC_BUG
  94         def_bool y
  95         depends on BUG
  96         select GENERIC_BUG_RELATIVE_POINTERS if X86_64
  97
  98 config GENERIC_BUG_RELATIVE_POINTERS
  99         bool
 100
 101 config GENERIC_HWEIGHT
 102         def_bool y
 103
 104 config GENERIC_GPIO
 105         bool
 106
 107 config ARCH_MAY_HAVE_PC_FDC
 108         def_bool y
 109
 110 config RWSEM_GENERIC_SPINLOCK
 111         def_bool !X86_XADD
 112
 113 config RWSEM_XCHGADD_ALGORITHM
 114         def_bool X86_XADD
 115
 116 config ARCH_HAS_CPU_IDLE_WAIT
 117         def_bool y
 118
 119 config GENERIC_CALIBRATE_DELAY
 120         def_bool y
 121
 122 config GENERIC_TIME_VSYSCALL
 123         bool
 124         default X86_64
 125
 126 config ARCH_HAS_CPU_RELAX
 127         def_bool y
 128
 129 config ARCH_HAS_DEFAULT_IDLE
 130         def_bool y
 131
 132 config ARCH_HAS_CACHE_LINE_SIZE
 133         def_bool y
 134
 135 config HAVE_SETUP_PER_CPU_AREA
 136         def_bool y
 137
 138 config HAVE_CPUMASK_OF_CPU_MAP
 139         def_bool X86_64_SMP
 140
 141 config ARCH_HIBERNATION_POSSIBLE
 142         def_bool y
 143
 144 config ARCH_SUSPEND_POSSIBLE
 145         def_bool y
 146
 147 config ZONE_DMA32
 148         bool
 149         default X86_64
 150
 151 config ARCH_POPULATES_NODE_MAP
 152         def_bool y
 153
 154 config AUDIT_ARCH
 155         bool
 156         default X86_64
 157
 158 config ARCH_SUPPORTS_OPTIMIZED_INLINING
 159         def_bool y
 160
 161 # Use the generic interrupt handling code in kernel/irq/:
 162 config GENERIC_HARDIRQS
 163         bool
 164         default y
 165
 166 config GENERIC_IRQ_PROBE
 167         bool
 168         default y
 169
 170 config GENERIC_PENDING_IRQ
 171         bool
 172         depends on GENERIC_HARDIRQS && SMP
 173         default y
 174
 175 config USE_GENERIC_SMP_HELPERS
 176         def_bool y
 177         depends on SMP
 178
 179 config X86_32_SMP
 180         def_bool y
 181         depends on X86_32 && SMP
 182
 183 config X86_64_SMP
 184         def_bool y
 185         depends on X86_64 && SMP
 186
 187 config X86_HT
 188         bool
 189         depends on SMP
 190         default y
 191
 192 config X86_TRAMPOLINE
 193         bool
 194         depends on SMP || (64BIT && ACPI_SLEEP)
 195         default y
 196
 197 config X86_32_LAZY_GS
 198         def_bool y
 199         depends on X86_32 && !CC_STACKPROTECTOR
 200
 201 config KTIME_SCALAR
 202         def_bool X86_32
 203 source "init/Kconfig"
 204 source "kernel/Kconfig.freezer"
 205
 206 menu "Processor type and features"
 207
 208 source "kernel/time/Kconfig"
 209
 210 config SMP
 211         bool "Symmetric multi-processing support"
 212         ---help---
 213           This enables support for systems with more than one CPU. If you have
 214           a system with only one CPU, like most personal computers, say N. If
 215           you have a system with more than one CPU, say Y.
 216
 217           If you say N here, the kernel will run on single and multiprocessor
 218           machines, but will use only one CPU of a multiprocessor machine. If
 219           you say Y here, the kernel will run on many, but not all,
 220           singleprocessor machines. On a singleprocessor machine, the kernel
 221           will run faster if you say N here.
 222
 223           Note that if you say Y here and choose architecture "586" or
 224           "Pentium" under "Processor family", the kernel will not work on 486
 225           architectures. Similarly, multiprocessor kernels for the "PPro"
 226           architecture may not work on all Pentium based boards.
 227
 228           People using multiprocessor machines who say Y here should also say
 229           Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
 230           Management" code will be disabled if you say Y here.
 231
 232           See also <file:Documentation/i386/IO-APIC.txt>,
 233           <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
 234           <http://www.tldp.org/docs.html#howto>.
 235
 236           If you don't know what to do here, say N.
 237
 238 config X86_X2APIC
 239         bool "Support x2apic"
 240         depends on X86_LOCAL_APIC && X86_64
 241         ---help---
 242           This enables x2apic support on CPUs that have this feature.
 243
 244           This allows 32-bit apic IDs (so it can support very large systems),
 245           and accesses the local apic via MSRs not via mmio.
 246
 247           ( On certain CPU models you may need to enable INTR_REMAP too,
 248             to get functional x2apic mode. )
 249
 250           If you don't know what to do here, say N.
 251
 252 config SPARSE_IRQ
 253         bool "Support sparse irq numbering"
 254         depends on PCI_MSI || HT_IRQ
 255         ---help---
 256           This enables support for sparse irqs. This is useful for distro
 257           kernels that want to define a high CONFIG_NR_CPUS value but still
 258           want to have low kernel memory footprint on smaller machines.
 259
 260           ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
 261             out the irq_desc[] array in a more NUMA-friendly way. )
 262
 263           If you don't know what to do here, say N.
 264
 265 config NUMA_MIGRATE_IRQ_DESC
 266         bool "Move irq desc when changing irq smp_affinity"
 267         depends on SPARSE_IRQ && NUMA
 268         default n
 269         ---help---
 270           This enables moving irq_desc to cpu/node that irq will use handled.
 271
 272           If you don't know what to do here, say N.
 273
 274 config X86_MPPARSE
 275         bool "Enable MPS table" if ACPI
 276         default y
 277         depends on X86_LOCAL_APIC
 278         ---help---
 279           For old smp systems that do not have proper acpi support. Newer systems
 280           (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
 281
 282 config X86_BIGSMP
 283         bool "Support for big SMP systems with more than 8 CPUs"
 284         depends on X86_32 && SMP
 285         ---help---
 286           This option is needed for the systems that have more than 8 CPUs
 287
 288 config X86_EXTENDED_PLATFORM
 289         bool "Support for extended (non-PC) x86 platforms"
 290         default y
 291         ---help---
 292           If you disable this option then the kernel will only support
 293           standard PC platforms. (which covers the vast majority of
 294           systems out there.)
 295
 296           If you enable this option then you'll be able to select a number
 297           of non-PC x86 platforms.
 298
 299           If you have one of these systems, or if you want to build a
 300           generic distribution kernel, say Y here - otherwise say N.
 301
 302 # This is an alphabetically sorted list of 64 bit extended platforms
 303 # Please maintain the alphabetic order if and when there are additions
 304
 305 config X86_VSMP
 306         bool "ScaleMP vSMP"
 307         select PARAVIRT
 308         depends on X86_64 && PCI
 309         depends on X86_EXTENDED_PLATFORM
 310         ---help---
 311           Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
 312           supposed to run on these EM64T-based machines.  Only choose this option
 313           if you have one of these machines.
 314
 315 config X86_UV
 316         bool "SGI Ultraviolet"
 317         depends on X86_64
 318         depends on X86_EXTENDED_PLATFORM
 319         select X86_X2APIC
 320         ---help---
 321           This option is needed in order to support SGI Ultraviolet systems.
 322           If you don't have one of these, you should say N here.
 323
 324 # Following is an alphabetically sorted list of 32 bit extended platforms
 325 # Please maintain the alphabetic order if and when there are additions
 326
 327 config X86_ELAN
 328         bool "AMD Elan"
 329         depends on X86_32
 330         depends on X86_EXTENDED_PLATFORM
 331         ---help---
 332           Select this for an AMD Elan processor.
 333
 334           Do not use this option for K6/Athlon/Opteron processors!
 335
 336           If unsure, choose "PC-compatible" instead.
 337
 338 config X86_RDC321X
 339         bool "RDC R-321x SoC"
 340         depends on X86_32
 341         depends on X86_EXTENDED_PLATFORM
 342         select M486
 343         select X86_REBOOTFIXUPS
 344         ---help---
 345           This option is needed for RDC R-321x system-on-chip, also known
 346           as R-8610-(G).
 347           If you don't have one of these chips, you should say N here.
 348
 349 config X86_32_NON_STANDARD
 350         bool "Support non-standard 32-bit SMP architectures"
 351         depends on X86_32 && SMP
 352         depends on X86_EXTENDED_PLATFORM
 353         ---help---
 354           This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
 355           subarchitectures.  It is intended for a generic binary kernel.
 356           if you select them all, kernel will probe it one by one. and will
 357           fallback to default.
 358
 359 # Alphabetically sorted list of Non standard 32 bit platforms
 360
 361 config X86_NUMAQ
 362         bool "NUMAQ (IBM/Sequent)"
 363         depends on X86_32_NON_STANDARD
 364         select NUMA
 365         select X86_MPPARSE
 366         ---help---
 367           This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
 368           NUMA multiquad box. This changes the way that processors are
 369           bootstrapped, and uses Clustered Logical APIC addressing mode instead
 370           of Flat Logical.  You will need a new lynxer.elf file to flash your
 371           firmware with - send email to <Martin.Bligh@us.ibm.com>.
 372
 373 config X86_VISWS
 374         bool "SGI 320/540 (Visual Workstation)"
 375         depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
 376         depends on X86_32_NON_STANDARD
 377         ---help---
 378           The SGI Visual Workstation series is an IA32-based workstation
 379           based on SGI systems chips with some legacy PC hardware attached.
 380
 381           Say Y here to create a kernel to run on the SGI 320 or 540.
 382
 383           A kernel compiled for the Visual Workstation will run on general
 384           PCs as well. See <file:Documentation/sgi-visws.txt> for details.
 385
 386 config X86_SUMMIT
 387         bool "Summit/EXA (IBM x440)"
 388         depends on X86_32_NON_STANDARD
 389         ---help---
 390           This option is needed for IBM systems that use the Summit/EXA chipset.
 391           In particular, it is needed for the x440.
 392
 393 config X86_ES7000
 394         bool "Unisys ES7000 IA32 series"
 395         depends on X86_32_NON_STANDARD && X86_BIGSMP
 396         ---help---
 397           Support for Unisys ES7000 systems.  Say 'Y' here if this kernel is
 398           supposed to run on an IA32-based Unisys ES7000 system.
 399
 400 config X86_VOYAGER
 401         bool "Voyager (NCR)"
 402         depends on SMP && !PCI && BROKEN
 403         depends on X86_32_NON_STANDARD
 404         ---help---
 405           Voyager is an MCA-based 32-way capable SMP architecture proprietary
 406           to NCR Corp.  Machine classes 345x/35xx/4100/51xx are Voyager-based.
 407
 408           *** WARNING ***
 409
 410           If you do not specifically know you have a Voyager based machine,
 411           say N here, otherwise the kernel you build will not be bootable.
 412
 413 config SCHED_OMIT_FRAME_POINTER
 414         def_bool y
 415         prompt "Single-depth WCHAN output"
 416         depends on X86
 417         ---help---
 418           Calculate simpler /proc/<PID>/wchan values. If this option
 419           is disabled then wchan values will recurse back to the
 420           caller function. This provides more accurate wchan values,
 421           at the expense of slightly more scheduling overhead.
 422
 423           If in doubt, say "Y".
 424
 425 menuconfig PARAVIRT_GUEST
 426         bool "Paravirtualized guest support"
 427         ---help---
 428           Say Y here to get to see options related to running Linux under
 429           various hypervisors.  This option alone does not add any kernel code.
 430
 431           If you say N, all options in this submenu will be skipped and disabled.
 432
 433 if PARAVIRT_GUEST
 434
 435 source "arch/x86/xen/Kconfig"
 436
 437 config VMI
 438         bool "VMI Guest support"
 439         select PARAVIRT
 440         depends on X86_32
 441         ---help---
 442           VMI provides a paravirtualized interface to the VMware ESX server
 443           (it could be used by other hypervisors in theory too, but is not
 444           at the moment), by linking the kernel to a GPL-ed ROM module
 445           provided by the hypervisor.
 446
 447 config KVM_CLOCK
 448         bool "KVM paravirtualized clock"
 449         select PARAVIRT
 450         select PARAVIRT_CLOCK
 451         ---help---
 452           Turning on this option will allow you to run a paravirtualized clock
 453           when running over the KVM hypervisor. Instead of relying on a PIT
 454           (or probably other) emulation by the underlying device model, the host
 455           provides the guest with timing infrastructure such as time of day, and
 456           system time
 457
 458 config KVM_GUEST
 459         bool "KVM Guest support"
 460         select PARAVIRT
 461         ---help---
 462           This option enables various optimizations for running under the KVM
 463           hypervisor.
 464
 465 source "arch/x86/lguest/Kconfig"
 466
 467 config PARAVIRT
 468         bool "Enable paravirtualization code"
 469         ---help---
 470           This changes the kernel so it can modify itself when it is run
 471           under a hypervisor, potentially improving performance significantly
 472           over full virtualization.  However, when run without a hypervisor
 473           the kernel is theoretically slower and slightly larger.
 474
 475 config PARAVIRT_CLOCK
 476         bool
 477         default n
 478
 479 endif
 480
 481 config PARAVIRT_DEBUG
 482         bool "paravirt-ops debugging"
 483         depends on PARAVIRT && DEBUG_KERNEL
 484         ---help---
 485           Enable to debug paravirt_ops internals.  Specifically, BUG if
 486           a paravirt_op is missing when it is called.
 487
 488 config MEMTEST
 489         bool "Memtest"
 490         ---help---
 491           This option adds a kernel parameter 'memtest', which allows memtest
 492           to be set.
 493                 memtest=0, mean disabled; -- default
 494                 memtest=1, mean do 1 test pattern;
 495                 ...
 496                 memtest=4, mean do 4 test patterns.
 497           If you are unsure how to answer this question, answer N.
 498
 499 config X86_SUMMIT_NUMA
 500         def_bool y
 501         depends on X86_32 && NUMA && X86_32_NON_STANDARD
 502
 503 config X86_CYCLONE_TIMER
 504         def_bool y
 505         depends on X86_32_NON_STANDARD
 506
 507 source "arch/x86/Kconfig.cpu"
 508
 509 config HPET_TIMER
 510         def_bool X86_64
 511         prompt "HPET Timer Support" if X86_32
 512         ---help---
 513           Use the IA-PC HPET (High Precision Event Timer) to manage
 514           time in preference to the PIT and RTC, if a HPET is
 515           present.
 516           HPET is the next generation timer replacing legacy 8254s.
 517           The HPET provides a stable time base on SMP
 518           systems, unlike the TSC, but it is more expensive to access,
 519           as it is off-chip.  You can find the HPET spec at
 520           <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
 521
 522           You can safely choose Y here.  However, HPET will only be
 523           activated if the platform and the BIOS support this feature.
 524           Otherwise the 8254 will be used for timing services.
 525
 526           Choose N to continue using the legacy 8254 timer.
 527
 528 config HPET_EMULATE_RTC
 529         def_bool y
 530         depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
 531
 532 # Mark as embedded because too many people got it wrong.
 533 # The code disables itself when not needed.
 534 config DMI
 535         default y
 536         bool "Enable DMI scanning" if EMBEDDED
 537         ---help---
 538           Enabled scanning of DMI to identify machine quirks. Say Y
 539           here unless you have verified that your setup is not
 540           affected by entries in the DMI blacklist. Required by PNP
 541           BIOS code.
 542
 543 config GART_IOMMU
 544         bool "GART IOMMU support" if EMBEDDED
 545         default y
 546         select SWIOTLB
 547         select AGP
 548         depends on X86_64 && PCI
 549         ---help---
 550           Support for full DMA access of devices with 32bit memory access only
 551           on systems with more than 3GB. This is usually needed for USB,
 552           sound, many IDE/SATA chipsets and some other devices.
 553           Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
 554           based hardware IOMMU and a software bounce buffer based IOMMU used
 555           on Intel systems and as fallback.
 556           The code is only active when needed (enough memory and limited
 557           device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
 558           too.
 559
 560 config CALGARY_IOMMU
 561         bool "IBM Calgary IOMMU support"
 562         select SWIOTLB
 563         depends on X86_64 && PCI && EXPERIMENTAL
 564         ---help---
 565           Support for hardware IOMMUs in IBM's xSeries x366 and x460
 566           systems. Needed to run systems with more than 3GB of memory
 567           properly with 32-bit PCI devices that do not support DAC
 568           (Double Address Cycle). Calgary also supports bus level
 569           isolation, where all DMAs pass through the IOMMU.  This
 570           prevents them from going anywhere except their intended
 571           destination. This catches hard-to-find kernel bugs and
 572           mis-behaving drivers and devices that do not use the DMA-API
 573           properly to set up their DMA buffers.  The IOMMU can be
 574           turned off at boot time with the iommu=off parameter.
 575           Normally the kernel will make the right choice by itself.
 576           If unsure, say Y.
 577
 578 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
 579         def_bool y
 580         prompt "Should Calgary be enabled by default?"
 581         depends on CALGARY_IOMMU
 582         ---help---
 583           Should Calgary be enabled by default? if you choose 'y', Calgary
 584           will be used (if it exists). If you choose 'n', Calgary will not be
 585           used even if it exists. If you choose 'n' and would like to use
 586           Calgary anyway, pass 'iommu=calgary' on the kernel command line.
 587           If unsure, say Y.
 588
 589 config AMD_IOMMU
 590         bool "AMD IOMMU support"
 591         select SWIOTLB
 592         select PCI_MSI
 593         depends on X86_64 && PCI && ACPI
 594         ---help---
 595           With this option you can enable support for AMD IOMMU hardware in
 596           your system. An IOMMU is a hardware component which provides
 597           remapping of DMA memory accesses from devices. With an AMD IOMMU you
 598           can isolate the the DMA memory of different devices and protect the
 599           system from misbehaving device drivers or hardware.
 600
 601           You can find out if your system has an AMD IOMMU if you look into
 602           your BIOS for an option to enable it or if you have an IVRS ACPI
 603           table.
 604
 605 config AMD_IOMMU_STATS
 606         bool "Export AMD IOMMU statistics to debugfs"
 607         depends on AMD_IOMMU
 608         select DEBUG_FS
 609         ---help---
 610           This option enables code in the AMD IOMMU driver to collect various
 611           statistics about whats happening in the driver and exports that
 612           information to userspace via debugfs.
 613           If unsure, say N.
 614
 615 # need this always selected by IOMMU for the VIA workaround
 616 config SWIOTLB
 617         def_bool y if X86_64
 618         ---help---
 619           Support for software bounce buffers used on x86-64 systems
 620           which don't have a hardware IOMMU (e.g. the current generation
 621           of Intel's x86-64 CPUs). Using this PCI devices which can only
 622           access 32-bits of memory can be used on systems with more than
 623           3 GB of memory. If unsure, say Y.
 624
 625 config IOMMU_HELPER
 626         def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
 627
 628 config IOMMU_API
 629         def_bool (AMD_IOMMU || DMAR)
 630
 631 config MAXSMP
 632         bool "Configure Maximum number of SMP Processors and NUMA Nodes"
 633         depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
 634         select CPUMASK_OFFSTACK
 635         default n
 636         ---help---
 637           Configure maximum number of CPUS and NUMA Nodes for this architecture.
 638           If unsure, say N.
 639
 640 config NR_CPUS
 641         int "Maximum number of CPUs" if SMP && !MAXSMP
 642         range 2 512 if SMP && !MAXSMP
 643         default "1" if !SMP
 644         default "4096" if MAXSMP
 645         default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
 646         default "8" if SMP
 647         ---help---
 648           This allows you to specify the maximum number of CPUs which this
 649           kernel will support.  The maximum supported value is 512 and the
 650           minimum value which makes sense is 2.
 651
 652           This is purely to save memory - each supported CPU adds
 653           approximately eight kilobytes to the kernel image.
 654
 655 config SCHED_SMT
 656         bool "SMT (Hyperthreading) scheduler support"
 657         depends on X86_HT
 658         ---help---
 659           SMT scheduler support improves the CPU scheduler's decision making
 660           when dealing with Intel Pentium 4 chips with HyperThreading at a
 661           cost of slightly increased overhead in some places. If unsure say
 662           N here.
 663
 664 config SCHED_MC
 665         def_bool y
 666         prompt "Multi-core scheduler support"
 667         depends on X86_HT
 668         ---help---
 669           Multi-core scheduler support improves the CPU scheduler's decision
 670           making when dealing with multi-core CPU chips at a cost of slightly
 671           increased overhead in some places. If unsure say N here.
 672
 673 source "kernel/Kconfig.preempt"
 674
 675 config X86_UP_APIC
 676         bool "Local APIC support on uniprocessors"
 677         depends on X86_32 && !SMP && !X86_32_NON_STANDARD
 678         ---help---
 679           A local APIC (Advanced Programmable Interrupt Controller) is an
 680           integrated interrupt controller in the CPU. If you have a single-CPU
 681           system which has a processor with a local APIC, you can say Y here to
 682           enable and use it. If you say Y here even though your machine doesn't
 683           have a local APIC, then the kernel will still run with no slowdown at
 684           all. The local APIC supports CPU-generated self-interrupts (timer,
 685           performance counters), and the NMI watchdog which detects hard
 686           lockups.
 687
 688 config X86_UP_IOAPIC
 689         bool "IO-APIC support on uniprocessors"
 690         depends on X86_UP_APIC
 691         ---help---
 692           An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
 693           SMP-capable replacement for PC-style interrupt controllers. Most
 694           SMP systems and many recent uniprocessor systems have one.
 695
 696           If you have a single-CPU system with an IO-APIC, you can say Y here
 697           to use it. If you say Y here even though your machine doesn't have
 698           an IO-APIC, then the kernel will still run with no slowdown at all.
 699
 700 config X86_LOCAL_APIC
 701         def_bool y
 702         depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
 703
 704 config X86_IO_APIC
 705         def_bool y
 706         depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
 707
 708 config X86_VISWS_APIC
 709         def_bool y
 710         depends on X86_32 && X86_VISWS
 711
 712 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
 713         bool "Reroute for broken boot IRQs"
 714         default n
 715         depends on X86_IO_APIC
 716         ---help---
 717           This option enables a workaround that fixes a source of
 718           spurious interrupts. This is recommended when threaded
 719           interrupt handling is used on systems where the generation of
 720           superfluous "boot interrupts" cannot be disabled.
 721
 722           Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
 723           entry in the chipset's IO-APIC is masked (as, e.g. the RT
 724           kernel does during interrupt handling). On chipsets where this
 725           boot IRQ generation cannot be disabled, this workaround keeps
 726           the original IRQ line masked so that only the equivalent "boot
 727           IRQ" is delivered to the CPUs. The workaround also tells the
 728           kernel to set up the IRQ handler on the boot IRQ line. In this
 729           way only one interrupt is delivered to the kernel. Otherwise
 730           the spurious second interrupt may cause the kernel to bring
 731           down (vital) interrupt lines.
 732
 733           Only affects "broken" chipsets. Interrupt sharing may be
 734           increased on these systems.
 735
 736 config X86_MCE
 737         bool "Machine Check Exception"
 738         ---help---
 739           Machine Check Exception support allows the processor to notify the
 740           kernel if it detects a problem (e.g. overheating, component failure).
 741           The action the kernel takes depends on the severity of the problem,
 742           ranging from a warning message on the console, to halting the machine.
 743           Your processor must be a Pentium or newer to support this - check the
 744           flags in /proc/cpuinfo for mce.  Note that some older Pentium systems
 745           have a design flaw which leads to false MCE events - hence MCE is
 746           disabled on all P5 processors, unless explicitly enabled with "mce"
 747           as a boot argument.  Similarly, if MCE is built in and creates a
 748           problem on some new non-standard machine, you can boot with "nomce"
 749           to disable it.  MCE support simply ignores non-MCE processors like
 750           the 386 and 486, so nearly everyone can say Y here.
 751
 752 config X86_MCE_INTEL
 753         def_bool y
 754         prompt "Intel MCE features"
 755         depends on X86_64 && X86_MCE && X86_LOCAL_APIC
 756         ---help---
 757            Additional support for intel specific MCE features such as
 758            the thermal monitor.
 759
 760 config X86_MCE_AMD
 761         def_bool y
 762         prompt "AMD MCE features"
 763         depends on X86_64 && X86_MCE && X86_LOCAL_APIC
 764         ---help---
 765            Additional support for AMD specific MCE features such as
 766            the DRAM Error Threshold.
 767
 768 config X86_MCE_NONFATAL
 769         tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
 770         depends on X86_32 && X86_MCE
 771         ---help---
 772           Enabling this feature starts a timer that triggers every 5 seconds which
 773           will look at the machine check registers to see if anything happened.
 774           Non-fatal problems automatically get corrected (but still logged).
 775           Disable this if you don't want to see these messages.
 776           Seeing the messages this option prints out may be indicative of dying
 777           or out-of-spec (ie, overclocked) hardware.
 778           This option only does something on certain CPUs.
 779           (AMD Athlon/Duron and Intel Pentium 4)
 780
 781 config X86_MCE_P4THERMAL
 782         bool "check for P4 thermal throttling interrupt."
 783         depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
 784         ---help---
 785           Enabling this feature will cause a message to be printed when the P4
 786           enters thermal throttling.
 787
 788 config VM86
 789         bool "Enable VM86 support" if EMBEDDED
 790         default y
 791         depends on X86_32
 792         ---help---
 793           This option is required by programs like DOSEMU to run 16-bit legacy
 794           code on X86 processors. It also may be needed by software like
 795           XFree86 to initialize some video cards via BIOS. Disabling this
 796           option saves about 6k.
 797
 798 config TOSHIBA
 799         tristate "Toshiba Laptop support"
 800         depends on X86_32
 801         ---help---
 802           This adds a driver to safely access the System Management Mode of
 803           the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
 804           not work on models with a Phoenix BIOS. The System Management Mode
 805           is used to set the BIOS and power saving options on Toshiba portables.
 806
 807           For information on utilities to make use of this driver see the
 808           Toshiba Linux utilities web site at:
 809           <http://www.buzzard.org.uk/toshiba/>.
 810
 811           Say Y if you intend to run this kernel on a Toshiba portable.
 812           Say N otherwise.
 813
 814 config I8K
 815         tristate "Dell laptop support"
 816         ---help---
 817           This adds a driver to safely access the System Management Mode
 818           of the CPU on the Dell Inspiron 8000. The System Management Mode
 819           is used to read cpu temperature and cooling fan status and to
 820           control the fans on the I8K portables.
 821
 822           This driver has been tested only on the Inspiron 8000 but it may
 823           also work with other Dell laptops. You can force loading on other
 824           models by passing the parameter `force=1' to the module. Use at
 825           your own risk.
 826
 827           For information on utilities to make use of this driver see the
 828           I8K Linux utilities web site at:
 829           <http://people.debian.org/~dz/i8k/>
 830
 831           Say Y if you intend to run this kernel on a Dell Inspiron 8000.
 832           Say N otherwise.
 833
 834 config X86_REBOOTFIXUPS
 835         bool "Enable X86 board specific fixups for reboot"
 836         depends on X86_32
 837         ---help---
 838           This enables chipset and/or board specific fixups to be done
 839           in order to get reboot to work correctly. This is only needed on
 840           some combinations of hardware and BIOS. The symptom, for which
 841           this config is intended, is when reboot ends with a stalled/hung
 842           system.
 843
 844           Currently, the only fixup is for the Geode machines using
 845           CS5530A and CS5536 chipsets and the RDC R-321x SoC.
 846
 847           Say Y if you want to enable the fixup. Currently, it's safe to
 848           enable this option even if you don't need it.
 849           Say N otherwise.
 850
 851 config MICROCODE
 852         tristate "/dev/cpu/microcode - microcode support"
 853         select FW_LOADER
 854         ---help---
 855           If you say Y here, you will be able to update the microcode on
 856           certain Intel and AMD processors. The Intel support is for the
 857           IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
 858           Pentium 4, Xeon etc. The AMD support is for family 0x10 and
 859           0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
 860           You will obviously need the actual microcode binary data itself
 861           which is not shipped with the Linux kernel.
 862
 863           This option selects the general module only, you need to select
 864           at least one vendor specific module as well.
 865
 866           To compile this driver as a module, choose M here: the
 867           module will be called microcode.
 868
 869 config MICROCODE_INTEL
 870         bool "Intel microcode patch loading support"
 871         depends on MICROCODE
 872         default MICROCODE
 873         select FW_LOADER
 874         ---help---
 875           This options enables microcode patch loading support for Intel
 876           processors.
 877
 878           For latest news and information on obtaining all the required
 879           Intel ingredients for this driver, check:
 880           <http://www.urbanmyth.org/microcode/>.
 881
 882 config MICROCODE_AMD
 883         bool "AMD microcode patch loading support"
 884         depends on MICROCODE
 885         select FW_LOADER
 886         ---help---
 887           If you select this option, microcode patch loading support for AMD
 888           processors will be enabled.
 889
 890 config MICROCODE_OLD_INTERFACE
 891         def_bool y
 892         depends on MICROCODE
 893
 894 config X86_MSR
 895         tristate "/dev/cpu/*/msr - Model-specific register support"
 896         ---help---
 897           This device gives privileged processes access to the x86
 898           Model-Specific Registers (MSRs).  It is a character device with
 899           major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
 900           MSR accesses are directed to a specific CPU on multi-processor
 901           systems.
 902
 903 config X86_CPUID
 904         tristate "/dev/cpu/*/cpuid - CPU information support"
 905         ---help---
 906           This device gives processes access to the x86 CPUID instruction to
 907           be executed on a specific processor.  It is a character device
 908           with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
 909           /dev/cpu/31/cpuid.
 910
 911 choice
 912         prompt "High Memory Support"
 913         default HIGHMEM4G if !X86_NUMAQ
 914         default HIGHMEM64G if X86_NUMAQ
 915         depends on X86_32
 916
 917 config NOHIGHMEM
 918         bool "off"
 919         depends on !X86_NUMAQ
 920         ---help---
 921           Linux can use up to 64 Gigabytes of physical memory on x86 systems.
 922           However, the address space of 32-bit x86 processors is only 4
 923           Gigabytes large. That means that, if you have a large amount of
 924           physical memory, not all of it can be "permanently mapped" by the
 925           kernel. The physical memory that's not permanently mapped is called
 926           "high memory".
 927
 928           If you are compiling a kernel which will never run on a machine with
 929           more than 1 Gigabyte total physical RAM, answer "off" here (default
 930           choice and suitable for most users). This will result in a "3GB/1GB"
 931           split: 3GB are mapped so that each process sees a 3GB virtual memory
 932           space and the remaining part of the 4GB virtual memory space is used
 933           by the kernel to permanently map as much physical memory as
 934           possible.
 935
 936           If the machine has between 1 and 4 Gigabytes physical RAM, then
 937           answer "4GB" here.
 938
 939           If more than 4 Gigabytes is used then answer "64GB" here. This
 940           selection turns Intel PAE (Physical Address Extension) mode on.
 941           PAE implements 3-level paging on IA32 processors. PAE is fully
 942           supported by Linux, PAE mode is implemented on all recent Intel
 943           processors (Pentium Pro and better). NOTE: If you say "64GB" here,
 944           then the kernel will not boot on CPUs that don't support PAE!
 945
 946           The actual amount of total physical memory will either be
 947           auto detected or can be forced by using a kernel command line option
 948           such as "mem=256M". (Try "man bootparam" or see the documentation of
 949           your boot loader (lilo or loadlin) about how to pass options to the
 950           kernel at boot time.)
 951
 952           If unsure, say "off".
 953
 954 config HIGHMEM4G
 955         bool "4GB"
 956         depends on !X86_NUMAQ
 957         ---help---
 958           Select this if you have a 32-bit processor and between 1 and 4
 959           gigabytes of physical RAM.
 960
 961 config HIGHMEM64G
 962         bool "64GB"
 963         depends on !M386 && !M486
 964         select X86_PAE
 965         ---help---
 966           Select this if you have a 32-bit processor and more than 4
 967           gigabytes of physical RAM.
 968
 969 endchoice
 970
 971 choice
 972         depends on EXPERIMENTAL
 973         prompt "Memory split" if EMBEDDED
 974         default VMSPLIT_3G
 975         depends on X86_32
 976         ---help---
 977           Select the desired split between kernel and user memory.
 978
 979           If the address range available to the kernel is less than the
 980           physical memory installed, the remaining memory will be available
 981           as "high memory". Accessing high memory is a little more costly
 982           than low memory, as it needs to be mapped into the kernel first.
 983           Note that increasing the kernel address space limits the range
 984           available to user programs, making the address space there
 985           tighter.  Selecting anything other than the default 3G/1G split
 986           will also likely make your kernel incompatible with binary-only
 987           kernel modules.
 988
 989           If you are not absolutely sure what you are doing, leave this
 990           option alone!
 991
 992         config VMSPLIT_3G
 993                 bool "3G/1G user/kernel split"
 994         config VMSPLIT_3G_OPT
 995                 depends on !X86_PAE
 996                 bool "3G/1G user/kernel split (for full 1G low memory)"
 997         config VMSPLIT_2G
 998                 bool "2G/2G user/kernel split"
 999         config VMSPLIT_2G_OPT
1000                 depends on !X86_PAE
1001                 bool "2G/2G user/kernel split (for full 2G low memory)"
1002         config VMSPLIT_1G
1003                 bool "1G/3G user/kernel split"
1004 endchoice
1005
1006 config PAGE_OFFSET
1007         hex
1008         default 0xB0000000 if VMSPLIT_3G_OPT
1009         default 0x80000000 if VMSPLIT_2G
1010         default 0x78000000 if VMSPLIT_2G_OPT
1011         default 0x40000000 if VMSPLIT_1G
1012         default 0xC0000000
1013         depends on X86_32
1014
1015 config HIGHMEM
1016         def_bool y
1017         depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1018
1019 config X86_PAE
1020         bool "PAE (Physical Address Extension) Support"
1021         depends on X86_32 && !HIGHMEM4G
1022         ---help---
1023           PAE is required for NX support, and furthermore enables
1024           larger swapspace support for non-overcommit purposes. It
1025           has the cost of more pagetable lookup overhead, and also
1026           consumes more pagetable space per process.
1027
1028 config ARCH_PHYS_ADDR_T_64BIT
1029         def_bool X86_64 || X86_PAE
1030
1031 config DIRECT_GBPAGES
1032         bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1033         default y
1034         depends on X86_64
1035         ---help---
1036           Allow the kernel linear mapping to use 1GB pages on CPUs that
1037           support it. This can improve the kernel's performance a tiny bit by
1038           reducing TLB pressure. If in doubt, say "Y".
1039
1040 # Common NUMA Features
1041 config NUMA
1042         bool "Numa Memory Allocation and Scheduler Support"
1043         depends on SMP
1044         depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1045         default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1046         ---help---
1047           Enable NUMA (Non Uniform Memory Access) support.
1048
1049           The kernel will try to allocate memory used by a CPU on the
1050           local memory controller of the CPU and add some more
1051           NUMA awareness to the kernel.
1052
1053           For 64-bit this is recommended if the system is Intel Core i7
1054           (or later), AMD Opteron, or EM64T NUMA.
1055
1056           For 32-bit this is only needed on (rare) 32-bit-only platforms
1057           that support NUMA topologies, such as NUMAQ / Summit, or if you
1058           boot a 32-bit kernel on a 64-bit NUMA platform.
1059
1060           Otherwise, you should say N.
1061
1062 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1063         depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1064
1065 config K8_NUMA
1066         def_bool y
1067         prompt "Old style AMD Opteron NUMA detection"
1068         depends on X86_64 && NUMA && PCI
1069         ---help---
1070           Enable K8 NUMA node topology detection.  You should say Y here if
1071           you have a multi processor AMD K8 system. This uses an old
1072           method to read the NUMA configuration directly from the builtin
1073           Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1074           instead, which also takes priority if both are compiled in.
1075
1076 config X86_64_ACPI_NUMA
1077         def_bool y
1078         prompt "ACPI NUMA detection"
1079         depends on X86_64 && NUMA && ACPI && PCI
1080         select ACPI_NUMA
1081         ---help---
1082           Enable ACPI SRAT based node topology detection.
1083
1084 # Some NUMA nodes have memory ranges that span
1085 # other nodes.  Even though a pfn is valid and
1086 # between a node's start and end pfns, it may not
1087 # reside on that node.  See memmap_init_zone()
1088 # for details.
1089 config NODES_SPAN_OTHER_NODES
1090         def_bool y
1091         depends on X86_64_ACPI_NUMA
1092
1093 config NUMA_EMU
1094         bool "NUMA emulation"
1095         depends on X86_64 && NUMA
1096         ---help---
1097           Enable NUMA emulation. A flat machine will be split
1098           into virtual nodes when booted with "numa=fake=N", where N is the
1099           number of nodes. This is only useful for debugging.
1100
1101 config NODES_SHIFT
1102         int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1103         range 1 9   if X86_64
1104         default "9" if MAXSMP
1105         default "6" if X86_64
1106         default "4" if X86_NUMAQ
1107         default "3"
1108         depends on NEED_MULTIPLE_NODES
1109         ---help---
1110           Specify the maximum number of NUMA Nodes available on the target
1111           system.  Increases memory reserved to accomodate various tables.
1112
1113 config HAVE_ARCH_BOOTMEM_NODE
1114         def_bool y
1115         depends on X86_32 && NUMA
1116
1117 config ARCH_HAVE_MEMORY_PRESENT
1118         def_bool y
1119         depends on X86_32 && DISCONTIGMEM
1120
1121 config NEED_NODE_MEMMAP_SIZE
1122         def_bool y
1123         depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1124
1125 config HAVE_ARCH_ALLOC_REMAP
1126         def_bool y
1127         depends on X86_32 && NUMA
1128
1129 config ARCH_FLATMEM_ENABLE
1130         def_bool y
1131         depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1132
1133 config ARCH_DISCONTIGMEM_ENABLE
1134         def_bool y
1135         depends on NUMA && X86_32
1136
1137 config ARCH_DISCONTIGMEM_DEFAULT
1138         def_bool y
1139         depends on NUMA && X86_32
1140
1141 config ARCH_SPARSEMEM_DEFAULT
1142         def_bool y
1143         depends on X86_64
1144
1145 config ARCH_SPARSEMEM_ENABLE
1146         def_bool y
1147         depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1148         select SPARSEMEM_STATIC if X86_32
1149         select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1150
1151 config ARCH_SELECT_MEMORY_MODEL
1152         def_bool y
1153         depends on ARCH_SPARSEMEM_ENABLE
1154
1155 config ARCH_MEMORY_PROBE
1156         def_bool X86_64
1157         depends on MEMORY_HOTPLUG
1158
1159 source "mm/Kconfig"
1160
1161 config HIGHPTE
1162         bool "Allocate 3rd-level pagetables from highmem"
1163         depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1164         ---help---
1165           The VM uses one page table entry for each page of physical memory.
1166           For systems with a lot of RAM, this can be wasteful of precious
1167           low memory.  Setting this option will put user-space page table
1168           entries in high memory.
1169
1170 config X86_CHECK_BIOS_CORRUPTION
1171         bool "Check for low memory corruption"
1172         ---help---
1173           Periodically check for memory corruption in low memory, which
1174           is suspected to be caused by BIOS.  Even when enabled in the
1175           configuration, it is disabled at runtime.  Enable it by
1176           setting "memory_corruption_check=1" on the kernel command
1177           line.  By default it scans the low 64k of memory every 60
1178           seconds; see the memory_corruption_check_size and
1179           memory_corruption_check_period parameters in
1180           Documentation/kernel-parameters.txt to adjust this.
1181
1182           When enabled with the default parameters, this option has
1183           almost no overhead, as it reserves a relatively small amount
1184           of memory and scans it infrequently.  It both detects corruption
1185           and prevents it from affecting the running system.
1186
1187           It is, however, intended as a diagnostic tool; if repeatable
1188           BIOS-originated corruption always affects the same memory,
1189           you can use memmap= to prevent the kernel from using that
1190           memory.
1191
1192 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1193         bool "Set the default setting of memory_corruption_check"
1194         depends on X86_CHECK_BIOS_CORRUPTION
1195         default y
1196         ---help---
1197           Set whether the default state of memory_corruption_check is
1198           on or off.
1199
1200 config X86_RESERVE_LOW_64K
1201         bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1202         default y
1203         ---help---
1204           Reserve the first 64K of physical RAM on BIOSes that are known
1205           to potentially corrupt that memory range. A numbers of BIOSes are
1206           known to utilize this area during suspend/resume, so it must not
1207           be used by the kernel.
1208
1209           Set this to N if you are absolutely sure that you trust the BIOS
1210           to get all its memory reservations and usages right.
1211
1212           If you have doubts about the BIOS (e.g. suspend/resume does not
1213           work or there's kernel crashes after certain hardware hotplug
1214           events) and it's not AMI or Phoenix, then you might want to enable
1215           X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1216           corruption patterns.
1217
1218           Say Y if unsure.
1219
1220 config MATH_EMULATION
1221         bool
1222         prompt "Math emulation" if X86_32
1223         ---help---
1224           Linux can emulate a math coprocessor (used for floating point
1225           operations) if you don't have one. 486DX and Pentium processors have
1226           a math coprocessor built in, 486SX and 386 do not, unless you added
1227           a 487DX or 387, respectively. (The messages during boot time can
1228           give you some hints here ["man dmesg"].) Everyone needs either a
1229           coprocessor or this emulation.
1230
1231           If you don't have a math coprocessor, you need to say Y here; if you
1232           say Y here even though you have a coprocessor, the coprocessor will
1233           be used nevertheless. (This behavior can be changed with the kernel
1234           command line option "no387", which comes handy if your coprocessor
1235           is broken. Try "man bootparam" or see the documentation of your boot
1236           loader (lilo or loadlin) about how to pass options to the kernel at
1237           boot time.) This means that it is a good idea to say Y here if you
1238           intend to use this kernel on different machines.
1239
1240           More information about the internals of the Linux math coprocessor
1241           emulation can be found in <file:arch/x86/math-emu/README>.
1242
1243           If you are not sure, say Y; apart from resulting in a 66 KB bigger
1244           kernel, it won't hurt.
1245
1246 config MTRR
1247         bool "MTRR (Memory Type Range Register) support"
1248         ---help---
1249           On Intel P6 family processors (Pentium Pro, Pentium II and later)
1250           the Memory Type Range Registers (MTRRs) may be used to control
1251           processor access to memory ranges. This is most useful if you have
1252           a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1253           allows bus write transfers to be combined into a larger transfer
1254           before bursting over the PCI/AGP bus. This can increase performance
1255           of image write operations 2.5 times or more. Saying Y here creates a
1256           /proc/mtrr file which may be used to manipulate your processor's
1257           MTRRs. Typically the X server should use this.
1258
1259           This code has a reasonably generic interface so that similar
1260           control registers on other processors can be easily supported
1261           as well:
1262
1263           The Cyrix 6x86, 6x86MX and M II processors have Address Range
1264           Registers (ARRs) which provide a similar functionality to MTRRs. For
1265           these, the ARRs are used to emulate the MTRRs.
1266           The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1267           MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1268           write-combining. All of these processors are supported by this code
1269           and it makes sense to say Y here if you have one of them.
1270
1271           Saying Y here also fixes a problem with buggy SMP BIOSes which only
1272           set the MTRRs for the boot CPU and not for the secondary CPUs. This
1273           can lead to all sorts of problems, so it's good to say Y here.
1274
1275           You can safely say Y even if your machine doesn't have MTRRs, you'll
1276           just add about 9 KB to your kernel.
1277
1278           See <file:Documentation/x86/mtrr.txt> for more information.
1279
1280 config MTRR_SANITIZER
1281         def_bool y
1282         prompt "MTRR cleanup support"
1283         depends on MTRR
1284         ---help---
1285           Convert MTRR layout from continuous to discrete, so X drivers can
1286           add writeback entries.
1287
1288           Can be disabled with disable_mtrr_cleanup on the kernel command line.
1289           The largest mtrr entry size for a continous block can be set with
1290           mtrr_chunk_size.
1291
1292           If unsure, say Y.
1293
1294 config MTRR_SANITIZER_ENABLE_DEFAULT
1295         int "MTRR cleanup enable value (0-1)"
1296         range 0 1
1297         default "0"
1298         depends on MTRR_SANITIZER
1299         ---help---
1300           Enable mtrr cleanup default value
1301
1302 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1303         int "MTRR cleanup spare reg num (0-7)"
1304         range 0 7
1305         default "1"
1306         depends on MTRR_SANITIZER
1307         ---help---
1308           mtrr cleanup spare entries default, it can be changed via
1309           mtrr_spare_reg_nr=N on the kernel command line.
1310
1311 config X86_PAT
1312         bool
1313         prompt "x86 PAT support"
1314         depends on MTRR
1315         ---help---
1316           Use PAT attributes to setup page level cache control.
1317
1318           PATs are the modern equivalents of MTRRs and are much more
1319           flexible than MTRRs.
1320
1321           Say N here if you see bootup problems (boot crash, boot hang,
1322           spontaneous reboots) or a non-working video driver.
1323
1324           If unsure, say Y.
1325
1326 config EFI
1327         bool "EFI runtime service support"
1328         depends on ACPI
1329         ---help---
1330           This enables the kernel to use EFI runtime services that are
1331           available (such as the EFI variable services).
1332
1333           This option is only useful on systems that have EFI firmware.
1334           In addition, you should use the latest ELILO loader available
1335           at <http://elilo.sourceforge.net> in order to take advantage
1336           of EFI runtime services. However, even with this option, the
1337           resultant kernel should continue to boot on existing non-EFI
1338           platforms.
1339
1340 config SECCOMP
1341         def_bool y
1342         prompt "Enable seccomp to safely compute untrusted bytecode"
1343         ---help---
1344           This kernel feature is useful for number crunching applications
1345           that may need to compute untrusted bytecode during their
1346           execution. By using pipes or other transports made available to
1347           the process as file descriptors supporting the read/write
1348           syscalls, it's possible to isolate those applications in
1349           their own address space using seccomp. Once seccomp is
1350           enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1351           and the task is only allowed to execute a few safe syscalls
1352           defined by each seccomp mode.
1353
1354           If unsure, say Y. Only embedded should say N here.
1355
1356 config CC_STACKPROTECTOR_ALL
1357         bool
1358
1359 config CC_STACKPROTECTOR
1360         bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1361         select CC_STACKPROTECTOR_ALL
1362         ---help---
1363           This option turns on the -fstack-protector GCC feature. This
1364           feature puts, at the beginning of functions, a canary value on
1365           the stack just before the return address, and validates
1366           the value just before actually returning.  Stack based buffer
1367           overflows (that need to overwrite this return address) now also
1368           overwrite the canary, which gets detected and the attack is then
1369           neutralized via a kernel panic.
1370
1371           This feature requires gcc version 4.2 or above, or a distribution
1372           gcc with the feature backported. Older versions are automatically
1373           detected and for those versions, this configuration option is
1374           ignored. (and a warning is printed during bootup)
1375
1376 source kernel/Kconfig.hz
1377
1378 config KEXEC
1379         bool "kexec system call"
1380         ---help---
1381           kexec is a system call that implements the ability to shutdown your
1382           current kernel, and to start another kernel.  It is like a reboot
1383           but it is independent of the system firmware.   And like a reboot
1384           you can start any kernel with it, not just Linux.
1385
1386           The name comes from the similarity to the exec system call.
1387
1388           It is an ongoing process to be certain the hardware in a machine
1389           is properly shutdown, so do not be surprised if this code does not
1390           initially work for you.  It may help to enable device hotplugging
1391           support.  As of this writing the exact hardware interface is
1392           strongly in flux, so no good recommendation can be made.
1393
1394 config CRASH_DUMP
1395         bool "kernel crash dumps"
1396         depends on X86_64 || (X86_32 && HIGHMEM)
1397         ---help---
1398           Generate crash dump after being started by kexec.
1399           This should be normally only set in special crash dump kernels
1400           which are loaded in the main kernel with kexec-tools into
1401           a specially reserved region and then later executed after
1402           a crash by kdump/kexec. The crash dump kernel must be compiled
1403           to a memory address not used by the main kernel or BIOS using
1404           PHYSICAL_START, or it must be built as a relocatable image
1405           (CONFIG_RELOCATABLE=y).
1406           For more details see Documentation/kdump/kdump.txt
1407
1408 config KEXEC_JUMP
1409         bool "kexec jump (EXPERIMENTAL)"
1410         depends on EXPERIMENTAL
1411         depends on KEXEC && HIBERNATION && X86_32
1412         ---help---
1413           Jump between original kernel and kexeced kernel and invoke
1414           code in physical address mode via KEXEC
1415
1416 config PHYSICAL_START
1417         hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1418         default "0x1000000" if X86_NUMAQ
1419         default "0x200000" if X86_64
1420         default "0x100000"
1421         ---help---
1422           This gives the physical address where the kernel is loaded.
1423
1424           If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1425           bzImage will decompress itself to above physical address and
1426           run from there. Otherwise, bzImage will run from the address where
1427           it has been loaded by the boot loader and will ignore above physical
1428           address.
1429
1430           In normal kdump cases one does not have to set/change this option
1431           as now bzImage can be compiled as a completely relocatable image
1432           (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1433           address. This option is mainly useful for the folks who don't want
1434           to use a bzImage for capturing the crash dump and want to use a
1435           vmlinux instead. vmlinux is not relocatable hence a kernel needs
1436           to be specifically compiled to run from a specific memory area
1437           (normally a reserved region) and this option comes handy.
1438
1439           So if you are using bzImage for capturing the crash dump, leave
1440           the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1441           Otherwise if you plan to use vmlinux for capturing the crash dump
1442           change this value to start of the reserved region (Typically 16MB
1443           0x1000000). In other words, it can be set based on the "X" value as
1444           specified in the "crashkernel=YM@XM" command line boot parameter
1445           passed to the panic-ed kernel. Typically this parameter is set as
1446           crashkernel=64M@16M. Please take a look at
1447           Documentation/kdump/kdump.txt for more details about crash dumps.
1448
1449           Usage of bzImage for capturing the crash dump is recommended as
1450           one does not have to build two kernels. Same kernel can be used
1451           as production kernel and capture kernel. Above option should have
1452           gone away after relocatable bzImage support is introduced. But it
1453           is present because there are users out there who continue to use
1454           vmlinux for dump capture. This option should go away down the
1455           line.
1456
1457           Don't change this unless you know what you are doing.
1458
1459 config RELOCATABLE
1460         bool "Build a relocatable kernel (EXPERIMENTAL)"
1461         depends on EXPERIMENTAL
1462         ---help---
1463           This builds a kernel image that retains relocation information
1464           so it can be loaded someplace besides the default 1MB.
1465           The relocations tend to make the kernel binary about 10% larger,
1466           but are discarded at runtime.
1467
1468           One use is for the kexec on panic case where the recovery kernel
1469           must live at a different physical address than the primary
1470           kernel.
1471
1472           Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1473           it has been loaded at and the compile time physical address
1474           (CONFIG_PHYSICAL_START) is ignored.
1475
1476 config PHYSICAL_ALIGN
1477         hex
1478         prompt "Alignment value to which kernel should be aligned" if X86_32
1479         default "0x100000" if X86_32
1480         default "0x200000" if X86_64
1481         range 0x2000 0x400000
1482         ---help---
1483           This value puts the alignment restrictions on physical address
1484           where kernel is loaded and run from. Kernel is compiled for an
1485           address which meets above alignment restriction.
1486
1487           If bootloader loads the kernel at a non-aligned address and
1488           CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1489           address aligned to above value and run from there.
1490
1491           If bootloader loads the kernel at a non-aligned address and
1492           CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1493           load address and decompress itself to the address it has been
1494           compiled for and run from there. The address for which kernel is
1495           compiled already meets above alignment restrictions. Hence the
1496           end result is that kernel runs from a physical address meeting
1497           above alignment restrictions.
1498
1499           Don't change this unless you know what you are doing.
1500
1501 config HOTPLUG_CPU
1502         bool "Support for hot-pluggable CPUs"
1503         depends on SMP && HOTPLUG
1504         ---help---
1505           Say Y here to allow turning CPUs off and on. CPUs can be
1506           controlled through /sys/devices/system/cpu.
1507           ( Note: power management support will enable this option
1508             automatically on SMP systems. )
1509           Say N if you want to disable CPU hotplug.
1510
1511 config COMPAT_VDSO
1512         def_bool y
1513         prompt "Compat VDSO support"
1514         depends on X86_32 || IA32_EMULATION
1515         ---help---
1516           Map the 32-bit VDSO to the predictable old-style address too.
1517         ---help---
1518           Say N here if you are running a sufficiently recent glibc
1519           version (2.3.3 or later), to remove the high-mapped
1520           VDSO mapping and to exclusively use the randomized VDSO.
1521
1522           If unsure, say Y.
1523
1524 config CMDLINE_BOOL
1525         bool "Built-in kernel command line"
1526         default n
1527         ---help---
1528           Allow for specifying boot arguments to the kernel at
1529           build time.  On some systems (e.g. embedded ones), it is
1530           necessary or convenient to provide some or all of the
1531           kernel boot arguments with the kernel itself (that is,
1532           to not rely on the boot loader to provide them.)
1533
1534           To compile command line arguments into the kernel,
1535           set this option to 'Y', then fill in the
1536           the boot arguments in CONFIG_CMDLINE.
1537
1538           Systems with fully functional boot loaders (i.e. non-embedded)
1539           should leave this option set to 'N'.
1540
1541 config CMDLINE
1542         string "Built-in kernel command string"
1543         depends on CMDLINE_BOOL
1544         default ""
1545         ---help---
1546           Enter arguments here that should be compiled into the kernel
1547           image and used at boot time.  If the boot loader provides a
1548           command line at boot time, it is appended to this string to
1549           form the full kernel command line, when the system boots.
1550
1551           However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1552           change this behavior.
1553
1554           In most cases, the command line (whether built-in or provided
1555           by the boot loader) should specify the device for the root
1556           file system.
1557
1558 config CMDLINE_OVERRIDE
1559         bool "Built-in command line overrides boot loader arguments"
1560         default n
1561         depends on CMDLINE_BOOL
1562         ---help---
1563           Set this option to 'Y' to have the kernel ignore the boot loader
1564           command line, and use ONLY the built-in command line.
1565
1566           This is used to work around broken boot loaders.  This should
1567           be set to 'N' under normal conditions.
1568
1569 endmenu
1570
1571 config ARCH_ENABLE_MEMORY_HOTPLUG
1572         def_bool y
1573         depends on X86_64 || (X86_32 && HIGHMEM)
1574
1575 config ARCH_ENABLE_MEMORY_HOTREMOVE
1576         def_bool y
1577         depends on MEMORY_HOTPLUG
1578
1579 config HAVE_ARCH_EARLY_PFN_TO_NID
1580         def_bool X86_64
1581         depends on NUMA
1582
1583 menu "Power management and ACPI options"
1584
1585 config ARCH_HIBERNATION_HEADER
1586         def_bool y
1587         depends on X86_64 && HIBERNATION
1588
1589 source "kernel/power/Kconfig"
1590
1591 source "drivers/acpi/Kconfig"
1592
1593 config X86_APM_BOOT
1594         bool
1595         default y
1596         depends on APM || APM_MODULE
1597
1598 menuconfig APM
1599         tristate "APM (Advanced Power Management) BIOS support"
1600         depends on X86_32 && PM_SLEEP
1601         ---help---
1602           APM is a BIOS specification for saving power using several different
1603           techniques. This is mostly useful for battery powered laptops with
1604           APM compliant BIOSes. If you say Y here, the system time will be
1605           reset after a RESUME operation, the /proc/apm device will provide
1606           battery status information, and user-space programs will receive
1607           notification of APM "events" (e.g. battery status change).
1608
1609           If you select "Y" here, you can disable actual use of the APM
1610           BIOS by passing the "apm=off" option to the kernel at boot time.
1611
1612           Note that the APM support is almost completely disabled for
1613           machines with more than one CPU.
1614
1615           In order to use APM, you will need supporting software. For location
1616           and more information, read <file:Documentation/power/pm.txt> and the
1617           Battery Powered Linux mini-HOWTO, available from
1618           <http://www.tldp.org/docs.html#howto>.
1619
1620           This driver does not spin down disk drives (see the hdparm(8)
1621           manpage ("man 8 hdparm") for that), and it doesn't turn off
1622           VESA-compliant "green" monitors.
1623
1624           This driver does not support the TI 4000M TravelMate and the ACER
1625           486/DX4/75 because they don't have compliant BIOSes. Many "green"
1626           desktop machines also don't have compliant BIOSes, and this driver
1627           may cause those machines to panic during the boot phase.
1628
1629           Generally, if you don't have a battery in your machine, there isn't
1630           much point in using this driver and you should say N. If you get
1631           random kernel OOPSes or reboots that don't seem to be related to
1632           anything, try disabling/enabling this option (or disabling/enabling
1633           APM in your BIOS).
1634
1635           Some other things you should try when experiencing seemingly random,
1636           "weird" problems:
1637
1638           1) make sure that you have enough swap space and that it is
1639           enabled.
1640           2) pass the "no-hlt" option to the kernel
1641           3) switch on floating point emulation in the kernel and pass
1642           the "no387" option to the kernel
1643           4) pass the "floppy=nodma" option to the kernel
1644           5) pass the "mem=4M" option to the kernel (thereby disabling
1645           all but the first 4 MB of RAM)
1646           6) make sure that the CPU is not over clocked.
1647           7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1648           8) disable the cache from your BIOS settings
1649           9) install a fan for the video card or exchange video RAM
1650           10) install a better fan for the CPU
1651           11) exchange RAM chips
1652           12) exchange the motherboard.
1653
1654           To compile this driver as a module, choose M here: the
1655           module will be called apm.
1656
1657 if APM
1658
1659 config APM_IGNORE_USER_SUSPEND
1660         bool "Ignore USER SUSPEND"
1661         ---help---
1662           This option will ignore USER SUSPEND requests. On machines with a
1663           compliant APM BIOS, you want to say N. However, on the NEC Versa M
1664           series notebooks, it is necessary to say Y because of a BIOS bug.
1665
1666 config APM_DO_ENABLE
1667         bool "Enable PM at boot time"
1668         ---help---
1669           Enable APM features at boot time. From page 36 of the APM BIOS
1670           specification: "When disabled, the APM BIOS does not automatically
1671           power manage devices, enter the Standby State, enter the Suspend
1672           State, or take power saving steps in response to CPU Idle calls."
1673           This driver will make CPU Idle calls when Linux is idle (unless this
1674           feature is turned off -- see "Do CPU IDLE calls", below). This
1675           should always save battery power, but more complicated APM features
1676           will be dependent on your BIOS implementation. You may need to turn
1677           this option off if your computer hangs at boot time when using APM
1678           support, or if it beeps continuously instead of suspending. Turn
1679           this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1680           T400CDT. This is off by default since most machines do fine without
1681           this feature.
1682
1683 config APM_CPU_IDLE
1684         bool "Make CPU Idle calls when idle"
1685         ---help---
1686           Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1687           On some machines, this can activate improved power savings, such as
1688           a slowed CPU clock rate, when the machine is idle. These idle calls
1689           are made after the idle loop has run for some length of time (e.g.,
1690           333 mS). On some machines, this will cause a hang at boot time or
1691           whenever the CPU becomes idle. (On machines with more than one CPU,
1692           this option does nothing.)
1693
1694 config APM_DISPLAY_BLANK
1695         bool "Enable console blanking using APM"
1696         ---help---
1697           Enable console blanking using the APM. Some laptops can use this to
1698           turn off the LCD backlight when the screen blanker of the Linux
1699           virtual console blanks the screen. Note that this is only used by
1700           the virtual console screen blanker, and won't turn off the backlight
1701           when using the X Window system. This also doesn't have anything to
1702           do with your VESA-compliant power-saving monitor. Further, this
1703           option doesn't work for all laptops -- it might not turn off your
1704           backlight at all, or it might print a lot of errors to the console,
1705           especially if you are using gpm.
1706
1707 config APM_ALLOW_INTS
1708         bool "Allow interrupts during APM BIOS calls"
1709         ---help---
1710           Normally we disable external interrupts while we are making calls to
1711           the APM BIOS as a measure to lessen the effects of a badly behaving
1712           BIOS implementation.  The BIOS should reenable interrupts if it
1713           needs to.  Unfortunately, some BIOSes do not -- especially those in
1714           many of the newer IBM Thinkpads.  If you experience hangs when you
1715           suspend, try setting this to Y.  Otherwise, say N.
1716
1717 endif # APM
1718
1719 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1720
1721 source "drivers/cpuidle/Kconfig"
1722
1723 source "drivers/idle/Kconfig"
1724
1725 endmenu
1726
1727
1728 menu "Bus options (PCI etc.)"
1729
1730 config PCI
1731         bool "PCI support"
1732         default y
1733         select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1734         ---help---
1735           Find out whether you have a PCI motherboard. PCI is the name of a
1736           bus system, i.e. the way the CPU talks to the other stuff inside
1737           your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1738           VESA. If you have PCI, say Y, otherwise N.
1739
1740 choice
1741         prompt "PCI access mode"
1742         depends on X86_32 && PCI
1743         default PCI_GOANY
1744         ---help---
1745           On PCI systems, the BIOS can be used to detect the PCI devices and
1746           determine their configuration. However, some old PCI motherboards
1747           have BIOS bugs and may crash if this is done. Also, some embedded
1748           PCI-based systems don't have any BIOS at all. Linux can also try to
1749           detect the PCI hardware directly without using the BIOS.
1750
1751           With this option, you can specify how Linux should detect the
1752           PCI devices. If you choose "BIOS", the BIOS will be used,
1753           if you choose "Direct", the BIOS won't be used, and if you
1754           choose "MMConfig", then PCI Express MMCONFIG will be used.
1755           If you choose "Any", the kernel will try MMCONFIG, then the
1756           direct access method and falls back to the BIOS if that doesn't
1757           work. If unsure, go with the default, which is "Any".
1758
1759 config PCI_GOBIOS
1760         bool "BIOS"
1761
1762 config PCI_GOMMCONFIG
1763         bool "MMConfig"
1764
1765 config PCI_GODIRECT
1766         bool "Direct"
1767
1768 config PCI_GOOLPC
1769         bool "OLPC"
1770         depends on OLPC
1771
1772 config PCI_GOANY
1773         bool "Any"
1774
1775 endchoice
1776
1777 config PCI_BIOS
1778         def_bool y
1779         depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1780
1781 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1782 config PCI_DIRECT
1783         def_bool y
1784         depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1785
1786 config PCI_MMCONFIG
1787         def_bool y
1788         depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1789
1790 config PCI_OLPC
1791         def_bool y
1792         depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1793
1794 config PCI_DOMAINS
1795         def_bool y
1796         depends on PCI
1797
1798 config PCI_MMCONFIG
1799         bool "Support mmconfig PCI config space access"
1800         depends on X86_64 && PCI && ACPI
1801
1802 config DMAR
1803         bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1804         depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1805         ---help---
1806           DMA remapping (DMAR) devices support enables independent address
1807           translations for Direct Memory Access (DMA) from devices.
1808           These DMA remapping devices are reported via ACPI tables
1809           and include PCI device scope covered by these DMA
1810           remapping devices.
1811
1812 config DMAR_DEFAULT_ON
1813         def_bool n
1814         prompt "Enable DMA Remapping Devices by default"
1815         depends on DMAR
1816         help
1817           Selecting this option will enable a DMAR device at boot time if
1818           one is found. If this option is not selected, DMAR support can
1819           be enabled by passing intel_iommu=on to the kernel. It is
1820           recommended you say N here while the DMAR code remains
1821           experimental.
1822
1823 config DMAR_GFX_WA
1824         def_bool y
1825         prompt "Support for Graphics workaround"
1826         depends on DMAR
1827         ---help---
1828           Current Graphics drivers tend to use physical address
1829           for DMA and avoid using DMA APIs. Setting this config
1830           option permits the IOMMU driver to set a unity map for
1831           all the OS-visible memory. Hence the driver can continue
1832           to use physical addresses for DMA.
1833
1834 config DMAR_FLOPPY_WA
1835         def_bool y
1836         depends on DMAR
1837         ---help---
1838           Floppy disk drivers are know to bypass DMA API calls
1839           thereby failing to work when IOMMU is enabled. This
1840           workaround will setup a 1:1 mapping for the first
1841           16M to make floppy (an ISA device) work.
1842
1843 config INTR_REMAP
1844         bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1845         depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1846         select X86_X2APIC
1847         ---help---
1848           Supports Interrupt remapping for IO-APIC and MSI devices.
1849           To use x2apic mode in the CPU's which support x2APIC enhancements or
1850           to support platforms with CPU's having > 8 bit APIC ID, say Y.
1851
1852 source "drivers/pci/pcie/Kconfig"
1853
1854 source "drivers/pci/Kconfig"
1855
1856 # x86_64 have no ISA slots, but do have ISA-style DMA.
1857 config ISA_DMA_API
1858         def_bool y
1859
1860 if X86_32
1861
1862 config ISA
1863         bool "ISA support"
1864         ---help---
1865           Find out whether you have ISA slots on your motherboard.  ISA is the
1866           name of a bus system, i.e. the way the CPU talks to the other stuff
1867           inside your box.  Other bus systems are PCI, EISA, MicroChannel
1868           (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
1869           newer boards don't support it.  If you have ISA, say Y, otherwise N.
1870
1871 config EISA
1872         bool "EISA support"
1873         depends on ISA
1874         ---help---
1875           The Extended Industry Standard Architecture (EISA) bus was
1876           developed as an open alternative to the IBM MicroChannel bus.
1877
1878           The EISA bus provided some of the features of the IBM MicroChannel
1879           bus while maintaining backward compatibility with cards made for
1880           the older ISA bus.  The EISA bus saw limited use between 1988 and
1881           1995 when it was made obsolete by the PCI bus.
1882
1883           Say Y here if you are building a kernel for an EISA-based machine.
1884
1885           Otherwise, say N.
1886
1887 source "drivers/eisa/Kconfig"
1888
1889 config MCA
1890         bool "MCA support"
1891         ---help---
1892           MicroChannel Architecture is found in some IBM PS/2 machines and
1893           laptops.  It is a bus system similar to PCI or ISA. See
1894           <file:Documentation/mca.txt> (and especially the web page given
1895           there) before attempting to build an MCA bus kernel.
1896
1897 source "drivers/mca/Kconfig"
1898
1899 config SCx200
1900         tristate "NatSemi SCx200 support"
1901         ---help---
1902           This provides basic support for National Semiconductor's
1903           (now AMD's) Geode processors.  The driver probes for the
1904           PCI-IDs of several on-chip devices, so its a good dependency
1905           for other scx200_* drivers.
1906
1907           If compiled as a module, the driver is named scx200.
1908
1909 config SCx200HR_TIMER
1910         tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1911         depends on SCx200 && GENERIC_TIME
1912         default y
1913         ---help---
1914           This driver provides a clocksource built upon the on-chip
1915           27MHz high-resolution timer.  Its also a workaround for
1916           NSC Geode SC-1100's buggy TSC, which loses time when the
1917           processor goes idle (as is done by the scheduler).  The
1918           other workaround is idle=poll boot option.
1919
1920 config GEODE_MFGPT_TIMER
1921         def_bool y
1922         prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1923         depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1924         ---help---
1925           This driver provides a clock event source based on the MFGPT
1926           timer(s) in the CS5535 and CS5536 companion chip for the geode.
1927           MFGPTs have a better resolution and max interval than the
1928           generic PIT, and are suitable for use as high-res timers.
1929
1930 config OLPC
1931         bool "One Laptop Per Child support"
1932         default n
1933         ---help---
1934           Add support for detecting the unique features of the OLPC
1935           XO hardware.
1936
1937 endif # X86_32
1938
1939 config K8_NB
1940         def_bool y
1941         depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1942
1943 source "drivers/pcmcia/Kconfig"
1944
1945 source "drivers/pci/hotplug/Kconfig"
1946
1947 endmenu
1948
1949
1950 menu "Executable file formats / Emulations"
1951
1952 source "fs/Kconfig.binfmt"
1953
1954 config IA32_EMULATION
1955         bool "IA32 Emulation"
1956         depends on X86_64
1957         select COMPAT_BINFMT_ELF
1958         ---help---
1959           Include code to run 32-bit programs under a 64-bit kernel. You should
1960           likely turn this on, unless you're 100% sure that you don't have any
1961           32-bit programs left.
1962
1963 config IA32_AOUT
1964         tristate "IA32 a.out support"
1965         depends on IA32_EMULATION
1966         ---help---
1967           Support old a.out binaries in the 32bit emulation.
1968
1969 config COMPAT
1970         def_bool y
1971         depends on IA32_EMULATION
1972
1973 config COMPAT_FOR_U64_ALIGNMENT
1974         def_bool COMPAT
1975         depends on X86_64
1976
1977 config SYSVIPC_COMPAT
1978         def_bool y
1979         depends on COMPAT && SYSVIPC
1980
1981 endmenu
1982
1983
1984 config HAVE_ATOMIC_IOMAP
1985         def_bool y
1986         depends on X86_32
1987
1988 source "net/Kconfig"
1989
1990 source "drivers/Kconfig"
1991
1992 source "drivers/firmware/Kconfig"
1993
1994 source "fs/Kconfig"
1995
1996 source "arch/x86/Kconfig.debug"
1997
1998 source "security/Kconfig"
1999
2000 source "crypto/Kconfig"
2001
2002 source "arch/x86/kvm/Kconfig"
2003
2004 source "lib/Kconfig"