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         select HAVE_KERNEL_GZIP
  44         select HAVE_KERNEL_BZIP2
  45         select HAVE_KERNEL_LZMA
  46
  47 config ARCH_DEFCONFIG
  48         string
  49         default "arch/x86/configs/i386_defconfig" if X86_32
  50         default "arch/x86/configs/x86_64_defconfig" if X86_64
  51
  52 config GENERIC_TIME
  53         def_bool y
  54
  55 config GENERIC_CMOS_UPDATE
  56         def_bool y
  57
  58 config CLOCKSOURCE_WATCHDOG
  59         def_bool y
  60
  61 config GENERIC_CLOCKEVENTS
  62         def_bool y
  63
  64 config GENERIC_CLOCKEVENTS_BROADCAST
  65         def_bool y
  66         depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
  67
  68 config LOCKDEP_SUPPORT
  69         def_bool y
  70
  71 config STACKTRACE_SUPPORT
  72         def_bool y
  73
  74 config HAVE_LATENCYTOP_SUPPORT
  75         def_bool y
  76
  77 config FAST_CMPXCHG_LOCAL
  78         bool
  79         default y
  80
  81 config MMU
  82         def_bool y
  83
  84 config ZONE_DMA
  85         def_bool y
  86
  87 config SBUS
  88         bool
  89
  90 config GENERIC_ISA_DMA
  91         def_bool y
  92
  93 config GENERIC_IOMAP
  94         def_bool y
  95
  96 config GENERIC_BUG
  97         def_bool y
  98         depends on BUG
  99         select GENERIC_BUG_RELATIVE_POINTERS if X86_64
 100
 101 config GENERIC_BUG_RELATIVE_POINTERS
 102         bool
 103
 104 config GENERIC_HWEIGHT
 105         def_bool y
 106
 107 config GENERIC_GPIO
 108         bool
 109
 110 config ARCH_MAY_HAVE_PC_FDC
 111         def_bool y
 112
 113 config RWSEM_GENERIC_SPINLOCK
 114         def_bool !X86_XADD
 115
 116 config RWSEM_XCHGADD_ALGORITHM
 117         def_bool X86_XADD
 118
 119 config ARCH_HAS_CPU_IDLE_WAIT
 120         def_bool y
 121
 122 config GENERIC_CALIBRATE_DELAY
 123         def_bool y
 124
 125 config GENERIC_TIME_VSYSCALL
 126         bool
 127         default X86_64
 128
 129 config ARCH_HAS_CPU_RELAX
 130         def_bool y
 131
 132 config ARCH_HAS_DEFAULT_IDLE
 133         def_bool y
 134
 135 config ARCH_HAS_CACHE_LINE_SIZE
 136         def_bool y
 137
 138 config HAVE_SETUP_PER_CPU_AREA
 139         def_bool y
 140
 141 config HAVE_DYNAMIC_PER_CPU_AREA
 142         def_bool y
 143
 144 config HAVE_CPUMASK_OF_CPU_MAP
 145         def_bool X86_64_SMP
 146
 147 config ARCH_HIBERNATION_POSSIBLE
 148         def_bool y
 149
 150 config ARCH_SUSPEND_POSSIBLE
 151         def_bool y
 152
 153 config ZONE_DMA32
 154         bool
 155         default X86_64
 156
 157 config ARCH_POPULATES_NODE_MAP
 158         def_bool y
 159
 160 config AUDIT_ARCH
 161         bool
 162         default X86_64
 163
 164 config ARCH_SUPPORTS_OPTIMIZED_INLINING
 165         def_bool y
 166
 167 # Use the generic interrupt handling code in kernel/irq/:
 168 config GENERIC_HARDIRQS
 169         bool
 170         default y
 171
 172 config GENERIC_HARDIRQS_NO__DO_IRQ
 173        def_bool y
 174
 175 config GENERIC_IRQ_PROBE
 176         bool
 177         default y
 178
 179 config GENERIC_PENDING_IRQ
 180         bool
 181         depends on GENERIC_HARDIRQS && SMP
 182         default y
 183
 184 config USE_GENERIC_SMP_HELPERS
 185         def_bool y
 186         depends on SMP
 187
 188 config X86_32_SMP
 189         def_bool y
 190         depends on X86_32 && SMP
 191
 192 config X86_64_SMP
 193         def_bool y
 194         depends on X86_64 && SMP
 195
 196 config X86_HT
 197         bool
 198         depends on SMP
 199         default y
 200
 201 config X86_TRAMPOLINE
 202         bool
 203         depends on SMP || (64BIT && ACPI_SLEEP)
 204         default y
 205
 206 config X86_32_LAZY_GS
 207         def_bool y
 208         depends on X86_32 && !CC_STACKPROTECTOR
 209
 210 config KTIME_SCALAR
 211         def_bool X86_32
 212 source "init/Kconfig"
 213 source "kernel/Kconfig.freezer"
 214
 215 menu "Processor type and features"
 216
 217 source "kernel/time/Kconfig"
 218
 219 config SMP
 220         bool "Symmetric multi-processing support"
 221         ---help---
 222           This enables support for systems with more than one CPU. If you have
 223           a system with only one CPU, like most personal computers, say N. If
 224           you have a system with more than one CPU, say Y.
 225
 226           If you say N here, the kernel will run on single and multiprocessor
 227           machines, but will use only one CPU of a multiprocessor machine. If
 228           you say Y here, the kernel will run on many, but not all,
 229           singleprocessor machines. On a singleprocessor machine, the kernel
 230           will run faster if you say N here.
 231
 232           Note that if you say Y here and choose architecture "586" or
 233           "Pentium" under "Processor family", the kernel will not work on 486
 234           architectures. Similarly, multiprocessor kernels for the "PPro"
 235           architecture may not work on all Pentium based boards.
 236
 237           People using multiprocessor machines who say Y here should also say
 238           Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
 239           Management" code will be disabled if you say Y here.
 240
 241           See also <file:Documentation/i386/IO-APIC.txt>,
 242           <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
 243           <http://www.tldp.org/docs.html#howto>.
 244
 245           If you don't know what to do here, say N.
 246
 247 config X86_X2APIC
 248         bool "Support x2apic"
 249         depends on X86_LOCAL_APIC && X86_64
 250         ---help---
 251           This enables x2apic support on CPUs that have this feature.
 252
 253           This allows 32-bit apic IDs (so it can support very large systems),
 254           and accesses the local apic via MSRs not via mmio.
 255
 256           ( On certain CPU models you may need to enable INTR_REMAP too,
 257             to get functional x2apic mode. )
 258
 259           If you don't know what to do here, say N.
 260
 261 config SPARSE_IRQ
 262         bool "Support sparse irq numbering"
 263         depends on PCI_MSI || HT_IRQ
 264         ---help---
 265           This enables support for sparse irqs. This is useful for distro
 266           kernels that want to define a high CONFIG_NR_CPUS value but still
 267           want to have low kernel memory footprint on smaller machines.
 268
 269           ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
 270             out the irq_desc[] array in a more NUMA-friendly way. )
 271
 272           If you don't know what to do here, say N.
 273
 274 config NUMA_MIGRATE_IRQ_DESC
 275         bool "Move irq desc when changing irq smp_affinity"
 276         depends on SPARSE_IRQ && NUMA
 277         default n
 278         ---help---
 279           This enables moving irq_desc to cpu/node that irq will use handled.
 280
 281           If you don't know what to do here, say N.
 282
 283 config X86_MPPARSE
 284         bool "Enable MPS table" if ACPI
 285         default y
 286         depends on X86_LOCAL_APIC
 287         ---help---
 288           For old smp systems that do not have proper acpi support. Newer systems
 289           (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
 290
 291 config X86_BIGSMP
 292         bool "Support for big SMP systems with more than 8 CPUs"
 293         depends on X86_32 && SMP
 294         ---help---
 295           This option is needed for the systems that have more than 8 CPUs
 296
 297 if X86_32
 298 config X86_EXTENDED_PLATFORM
 299         bool "Support for extended (non-PC) x86 platforms"
 300         default y
 301         ---help---
 302           If you disable this option then the kernel will only support
 303           standard PC platforms. (which covers the vast majority of
 304           systems out there.)
 305
 306           If you enable this option then you'll be able to select support
 307           for the following (non-PC) 32 bit x86 platforms:
 308                 AMD Elan
 309                 NUMAQ (IBM/Sequent)
 310                 RDC R-321x SoC
 311                 SGI 320/540 (Visual Workstation)
 312                 Summit/EXA (IBM x440)
 313                 Unisys ES7000 IA32 series
 314
 315           If you have one of these systems, or if you want to build a
 316           generic distribution kernel, say Y here - otherwise say N.
 317 endif
 318
 319 if X86_64
 320 config X86_EXTENDED_PLATFORM
 321         bool "Support for extended (non-PC) x86 platforms"
 322         default y
 323         ---help---
 324           If you disable this option then the kernel will only support
 325           standard PC platforms. (which covers the vast majority of
 326           systems out there.)
 327
 328           If you enable this option then you'll be able to select support
 329           for the following (non-PC) 64 bit x86 platforms:
 330                 ScaleMP vSMP
 331                 SGI Ultraviolet
 332
 333           If you have one of these systems, or if you want to build a
 334           generic distribution kernel, say Y here - otherwise say N.
 335 endif
 336 # This is an alphabetically sorted list of 64 bit extended platforms
 337 # Please maintain the alphabetic order if and when there are additions
 338
 339 config X86_VSMP
 340         bool "ScaleMP vSMP"
 341         select PARAVIRT
 342         depends on X86_64 && PCI
 343         depends on X86_EXTENDED_PLATFORM
 344         ---help---
 345           Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
 346           supposed to run on these EM64T-based machines.  Only choose this option
 347           if you have one of these machines.
 348
 349 config X86_UV
 350         bool "SGI Ultraviolet"
 351         depends on X86_64
 352         depends on X86_EXTENDED_PLATFORM
 353         select X86_X2APIC
 354         ---help---
 355           This option is needed in order to support SGI Ultraviolet systems.
 356           If you don't have one of these, you should say N here.
 357
 358 # Following is an alphabetically sorted list of 32 bit extended platforms
 359 # Please maintain the alphabetic order if and when there are additions
 360
 361 config X86_ELAN
 362         bool "AMD Elan"
 363         depends on X86_32
 364         depends on X86_EXTENDED_PLATFORM
 365         ---help---
 366           Select this for an AMD Elan processor.
 367
 368           Do not use this option for K6/Athlon/Opteron processors!
 369
 370           If unsure, choose "PC-compatible" instead.
 371
 372 config X86_RDC321X
 373         bool "RDC R-321x SoC"
 374         depends on X86_32
 375         depends on X86_EXTENDED_PLATFORM
 376         select M486
 377         select X86_REBOOTFIXUPS
 378         ---help---
 379           This option is needed for RDC R-321x system-on-chip, also known
 380           as R-8610-(G).
 381           If you don't have one of these chips, you should say N here.
 382
 383 config X86_32_NON_STANDARD
 384         bool "Support non-standard 32-bit SMP architectures"
 385         depends on X86_32 && SMP
 386         depends on X86_EXTENDED_PLATFORM
 387         ---help---
 388           This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
 389           subarchitectures.  It is intended for a generic binary kernel.
 390           if you select them all, kernel will probe it one by one. and will
 391           fallback to default.
 392
 393 # Alphabetically sorted list of Non standard 32 bit platforms
 394
 395 config X86_NUMAQ
 396         bool "NUMAQ (IBM/Sequent)"
 397         depends on X86_32_NON_STANDARD
 398         select NUMA
 399         select X86_MPPARSE
 400         ---help---
 401           This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
 402           NUMA multiquad box. This changes the way that processors are
 403           bootstrapped, and uses Clustered Logical APIC addressing mode instead
 404           of Flat Logical.  You will need a new lynxer.elf file to flash your
 405           firmware with - send email to <Martin.Bligh@us.ibm.com>.
 406
 407 config X86_VISWS
 408         bool "SGI 320/540 (Visual Workstation)"
 409         depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
 410         depends on X86_32_NON_STANDARD
 411         ---help---
 412           The SGI Visual Workstation series is an IA32-based workstation
 413           based on SGI systems chips with some legacy PC hardware attached.
 414
 415           Say Y here to create a kernel to run on the SGI 320 or 540.
 416
 417           A kernel compiled for the Visual Workstation will run on general
 418           PCs as well. See <file:Documentation/sgi-visws.txt> for details.
 419
 420 config X86_SUMMIT
 421         bool "Summit/EXA (IBM x440)"
 422         depends on X86_32_NON_STANDARD
 423         ---help---
 424           This option is needed for IBM systems that use the Summit/EXA chipset.
 425           In particular, it is needed for the x440.
 426
 427 config X86_ES7000
 428         bool "Unisys ES7000 IA32 series"
 429         depends on X86_32_NON_STANDARD && X86_BIGSMP
 430         ---help---
 431           Support for Unisys ES7000 systems.  Say 'Y' here if this kernel is
 432           supposed to run on an IA32-based Unisys ES7000 system.
 433
 434 config SCHED_OMIT_FRAME_POINTER
 435         def_bool y
 436         prompt "Single-depth WCHAN output"
 437         depends on X86
 438         ---help---
 439           Calculate simpler /proc/<PID>/wchan values. If this option
 440           is disabled then wchan values will recurse back to the
 441           caller function. This provides more accurate wchan values,
 442           at the expense of slightly more scheduling overhead.
 443
 444           If in doubt, say "Y".
 445
 446 menuconfig PARAVIRT_GUEST
 447         bool "Paravirtualized guest support"
 448         ---help---
 449           Say Y here to get to see options related to running Linux under
 450           various hypervisors.  This option alone does not add any kernel code.
 451
 452           If you say N, all options in this submenu will be skipped and disabled.
 453
 454 if PARAVIRT_GUEST
 455
 456 source "arch/x86/xen/Kconfig"
 457
 458 config VMI
 459         bool "VMI Guest support"
 460         select PARAVIRT
 461         depends on X86_32
 462         ---help---
 463           VMI provides a paravirtualized interface to the VMware ESX server
 464           (it could be used by other hypervisors in theory too, but is not
 465           at the moment), by linking the kernel to a GPL-ed ROM module
 466           provided by the hypervisor.
 467
 468 config KVM_CLOCK
 469         bool "KVM paravirtualized clock"
 470         select PARAVIRT
 471         select PARAVIRT_CLOCK
 472         ---help---
 473           Turning on this option will allow you to run a paravirtualized clock
 474           when running over the KVM hypervisor. Instead of relying on a PIT
 475           (or probably other) emulation by the underlying device model, the host
 476           provides the guest with timing infrastructure such as time of day, and
 477           system time
 478
 479 config KVM_GUEST
 480         bool "KVM Guest support"
 481         select PARAVIRT
 482         ---help---
 483           This option enables various optimizations for running under the KVM
 484           hypervisor.
 485
 486 source "arch/x86/lguest/Kconfig"
 487
 488 config PARAVIRT
 489         bool "Enable paravirtualization code"
 490         ---help---
 491           This changes the kernel so it can modify itself when it is run
 492           under a hypervisor, potentially improving performance significantly
 493           over full virtualization.  However, when run without a hypervisor
 494           the kernel is theoretically slower and slightly larger.
 495
 496 config PARAVIRT_CLOCK
 497         bool
 498         default n
 499
 500 endif
 501
 502 config PARAVIRT_DEBUG
 503         bool "paravirt-ops debugging"
 504         depends on PARAVIRT && DEBUG_KERNEL
 505         ---help---
 506           Enable to debug paravirt_ops internals.  Specifically, BUG if
 507           a paravirt_op is missing when it is called.
 508
 509 config MEMTEST
 510         bool "Memtest"
 511         ---help---
 512           This option adds a kernel parameter 'memtest', which allows memtest
 513           to be set.
 514                 memtest=0, mean disabled; -- default
 515                 memtest=1, mean do 1 test pattern;
 516                 ...
 517                 memtest=4, mean do 4 test patterns.
 518           If you are unsure how to answer this question, answer N.
 519
 520 config X86_SUMMIT_NUMA
 521         def_bool y
 522         depends on X86_32 && NUMA && X86_32_NON_STANDARD
 523
 524 config X86_CYCLONE_TIMER
 525         def_bool y
 526         depends on X86_32_NON_STANDARD
 527
 528 source "arch/x86/Kconfig.cpu"
 529
 530 config HPET_TIMER
 531         def_bool X86_64
 532         prompt "HPET Timer Support" if X86_32
 533         ---help---
 534           Use the IA-PC HPET (High Precision Event Timer) to manage
 535           time in preference to the PIT and RTC, if a HPET is
 536           present.
 537           HPET is the next generation timer replacing legacy 8254s.
 538           The HPET provides a stable time base on SMP
 539           systems, unlike the TSC, but it is more expensive to access,
 540           as it is off-chip.  You can find the HPET spec at
 541           <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
 542
 543           You can safely choose Y here.  However, HPET will only be
 544           activated if the platform and the BIOS support this feature.
 545           Otherwise the 8254 will be used for timing services.
 546
 547           Choose N to continue using the legacy 8254 timer.
 548
 549 config HPET_EMULATE_RTC
 550         def_bool y
 551         depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
 552
 553 # Mark as embedded because too many people got it wrong.
 554 # The code disables itself when not needed.
 555 config DMI
 556         default y
 557         bool "Enable DMI scanning" if EMBEDDED
 558         ---help---
 559           Enabled scanning of DMI to identify machine quirks. Say Y
 560           here unless you have verified that your setup is not
 561           affected by entries in the DMI blacklist. Required by PNP
 562           BIOS code.
 563
 564 config GART_IOMMU
 565         bool "GART IOMMU support" if EMBEDDED
 566         default y
 567         select SWIOTLB
 568         select AGP
 569         depends on X86_64 && PCI
 570         ---help---
 571           Support for full DMA access of devices with 32bit memory access only
 572           on systems with more than 3GB. This is usually needed for USB,
 573           sound, many IDE/SATA chipsets and some other devices.
 574           Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
 575           based hardware IOMMU and a software bounce buffer based IOMMU used
 576           on Intel systems and as fallback.
 577           The code is only active when needed (enough memory and limited
 578           device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
 579           too.
 580
 581 config CALGARY_IOMMU
 582         bool "IBM Calgary IOMMU support"
 583         select SWIOTLB
 584         depends on X86_64 && PCI && EXPERIMENTAL
 585         ---help---
 586           Support for hardware IOMMUs in IBM's xSeries x366 and x460
 587           systems. Needed to run systems with more than 3GB of memory
 588           properly with 32-bit PCI devices that do not support DAC
 589           (Double Address Cycle). Calgary also supports bus level
 590           isolation, where all DMAs pass through the IOMMU.  This
 591           prevents them from going anywhere except their intended
 592           destination. This catches hard-to-find kernel bugs and
 593           mis-behaving drivers and devices that do not use the DMA-API
 594           properly to set up their DMA buffers.  The IOMMU can be
 595           turned off at boot time with the iommu=off parameter.
 596           Normally the kernel will make the right choice by itself.
 597           If unsure, say Y.
 598
 599 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
 600         def_bool y
 601         prompt "Should Calgary be enabled by default?"
 602         depends on CALGARY_IOMMU
 603         ---help---
 604           Should Calgary be enabled by default? if you choose 'y', Calgary
 605           will be used (if it exists). If you choose 'n', Calgary will not be
 606           used even if it exists. If you choose 'n' and would like to use
 607           Calgary anyway, pass 'iommu=calgary' on the kernel command line.
 608           If unsure, say Y.
 609
 610 config AMD_IOMMU
 611         bool "AMD IOMMU support"
 612         select SWIOTLB
 613         select PCI_MSI
 614         depends on X86_64 && PCI && ACPI
 615         ---help---
 616           With this option you can enable support for AMD IOMMU hardware in
 617           your system. An IOMMU is a hardware component which provides
 618           remapping of DMA memory accesses from devices. With an AMD IOMMU you
 619           can isolate the the DMA memory of different devices and protect the
 620           system from misbehaving device drivers or hardware.
 621
 622           You can find out if your system has an AMD IOMMU if you look into
 623           your BIOS for an option to enable it or if you have an IVRS ACPI
 624           table.
 625
 626 config AMD_IOMMU_STATS
 627         bool "Export AMD IOMMU statistics to debugfs"
 628         depends on AMD_IOMMU
 629         select DEBUG_FS
 630         ---help---
 631           This option enables code in the AMD IOMMU driver to collect various
 632           statistics about whats happening in the driver and exports that
 633           information to userspace via debugfs.
 634           If unsure, say N.
 635
 636 # need this always selected by IOMMU for the VIA workaround
 637 config SWIOTLB
 638         def_bool y if X86_64
 639         ---help---
 640           Support for software bounce buffers used on x86-64 systems
 641           which don't have a hardware IOMMU (e.g. the current generation
 642           of Intel's x86-64 CPUs). Using this PCI devices which can only
 643           access 32-bits of memory can be used on systems with more than
 644           3 GB of memory. If unsure, say Y.
 645
 646 config IOMMU_HELPER
 647         def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
 648
 649 config IOMMU_API
 650         def_bool (AMD_IOMMU || DMAR)
 651
 652 config MAXSMP
 653         bool "Configure Maximum number of SMP Processors and NUMA Nodes"
 654         depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
 655         select CPUMASK_OFFSTACK
 656         default n
 657         ---help---
 658           Configure maximum number of CPUS and NUMA Nodes for this architecture.
 659           If unsure, say N.
 660
 661 config NR_CPUS
 662         int "Maximum number of CPUs" if SMP && !MAXSMP
 663         range 2 512 if SMP && !MAXSMP
 664         default "1" if !SMP
 665         default "4096" if MAXSMP
 666         default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
 667         default "8" if SMP
 668         ---help---
 669           This allows you to specify the maximum number of CPUs which this
 670           kernel will support.  The maximum supported value is 512 and the
 671           minimum value which makes sense is 2.
 672
 673           This is purely to save memory - each supported CPU adds
 674           approximately eight kilobytes to the kernel image.
 675
 676 config SCHED_SMT
 677         bool "SMT (Hyperthreading) scheduler support"
 678         depends on X86_HT
 679         ---help---
 680           SMT scheduler support improves the CPU scheduler's decision making
 681           when dealing with Intel Pentium 4 chips with HyperThreading at a
 682           cost of slightly increased overhead in some places. If unsure say
 683           N here.
 684
 685 config SCHED_MC
 686         def_bool y
 687         prompt "Multi-core scheduler support"
 688         depends on X86_HT
 689         ---help---
 690           Multi-core scheduler support improves the CPU scheduler's decision
 691           making when dealing with multi-core CPU chips at a cost of slightly
 692           increased overhead in some places. If unsure say N here.
 693
 694 source "kernel/Kconfig.preempt"
 695
 696 config X86_UP_APIC
 697         bool "Local APIC support on uniprocessors"
 698         depends on X86_32 && !SMP && !X86_32_NON_STANDARD
 699         ---help---
 700           A local APIC (Advanced Programmable Interrupt Controller) is an
 701           integrated interrupt controller in the CPU. If you have a single-CPU
 702           system which has a processor with a local APIC, you can say Y here to
 703           enable and use it. If you say Y here even though your machine doesn't
 704           have a local APIC, then the kernel will still run with no slowdown at
 705           all. The local APIC supports CPU-generated self-interrupts (timer,
 706           performance counters), and the NMI watchdog which detects hard
 707           lockups.
 708
 709 config X86_UP_IOAPIC
 710         bool "IO-APIC support on uniprocessors"
 711         depends on X86_UP_APIC
 712         ---help---
 713           An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
 714           SMP-capable replacement for PC-style interrupt controllers. Most
 715           SMP systems and many recent uniprocessor systems have one.
 716
 717           If you have a single-CPU system with an IO-APIC, you can say Y here
 718           to use it. If you say Y here even though your machine doesn't have
 719           an IO-APIC, then the kernel will still run with no slowdown at all.
 720
 721 config X86_LOCAL_APIC
 722         def_bool y
 723         depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
 724
 725 config X86_IO_APIC
 726         def_bool y
 727         depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
 728
 729 config X86_VISWS_APIC
 730         def_bool y
 731         depends on X86_32 && X86_VISWS
 732
 733 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
 734         bool "Reroute for broken boot IRQs"
 735         default n
 736         depends on X86_IO_APIC
 737         ---help---
 738           This option enables a workaround that fixes a source of
 739           spurious interrupts. This is recommended when threaded
 740           interrupt handling is used on systems where the generation of
 741           superfluous "boot interrupts" cannot be disabled.
 742
 743           Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
 744           entry in the chipset's IO-APIC is masked (as, e.g. the RT
 745           kernel does during interrupt handling). On chipsets where this
 746           boot IRQ generation cannot be disabled, this workaround keeps
 747           the original IRQ line masked so that only the equivalent "boot
 748           IRQ" is delivered to the CPUs. The workaround also tells the
 749           kernel to set up the IRQ handler on the boot IRQ line. In this
 750           way only one interrupt is delivered to the kernel. Otherwise
 751           the spurious second interrupt may cause the kernel to bring
 752           down (vital) interrupt lines.
 753
 754           Only affects "broken" chipsets. Interrupt sharing may be
 755           increased on these systems.
 756
 757 config X86_MCE
 758         bool "Machine Check Exception"
 759         ---help---
 760           Machine Check Exception support allows the processor to notify the
 761           kernel if it detects a problem (e.g. overheating, component failure).
 762           The action the kernel takes depends on the severity of the problem,
 763           ranging from a warning message on the console, to halting the machine.
 764           Your processor must be a Pentium or newer to support this - check the
 765           flags in /proc/cpuinfo for mce.  Note that some older Pentium systems
 766           have a design flaw which leads to false MCE events - hence MCE is
 767           disabled on all P5 processors, unless explicitly enabled with "mce"
 768           as a boot argument.  Similarly, if MCE is built in and creates a
 769           problem on some new non-standard machine, you can boot with "nomce"
 770           to disable it.  MCE support simply ignores non-MCE processors like
 771           the 386 and 486, so nearly everyone can say Y here.
 772
 773 config X86_MCE_INTEL
 774         def_bool y
 775         prompt "Intel MCE features"
 776         depends on X86_64 && X86_MCE && X86_LOCAL_APIC
 777         ---help---
 778            Additional support for intel specific MCE features such as
 779            the thermal monitor.
 780
 781 config X86_MCE_AMD
 782         def_bool y
 783         prompt "AMD MCE features"
 784         depends on X86_64 && X86_MCE && X86_LOCAL_APIC
 785         ---help---
 786            Additional support for AMD specific MCE features such as
 787            the DRAM Error Threshold.
 788
 789 config X86_MCE_THRESHOLD
 790         depends on X86_MCE_AMD || X86_MCE_INTEL
 791         bool
 792         default y
 793
 794 config X86_MCE_NONFATAL
 795         tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
 796         depends on X86_32 && X86_MCE
 797         ---help---
 798           Enabling this feature starts a timer that triggers every 5 seconds which
 799           will look at the machine check registers to see if anything happened.
 800           Non-fatal problems automatically get corrected (but still logged).
 801           Disable this if you don't want to see these messages.
 802           Seeing the messages this option prints out may be indicative of dying
 803           or out-of-spec (ie, overclocked) hardware.
 804           This option only does something on certain CPUs.
 805           (AMD Athlon/Duron and Intel Pentium 4)
 806
 807 config X86_MCE_P4THERMAL
 808         bool "check for P4 thermal throttling interrupt."
 809         depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
 810         ---help---
 811           Enabling this feature will cause a message to be printed when the P4
 812           enters thermal throttling.
 813
 814 config VM86
 815         bool "Enable VM86 support" if EMBEDDED
 816         default y
 817         depends on X86_32
 818         ---help---
 819           This option is required by programs like DOSEMU to run 16-bit legacy
 820           code on X86 processors. It also may be needed by software like
 821           XFree86 to initialize some video cards via BIOS. Disabling this
 822           option saves about 6k.
 823
 824 config TOSHIBA
 825         tristate "Toshiba Laptop support"
 826         depends on X86_32
 827         ---help---
 828           This adds a driver to safely access the System Management Mode of
 829           the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
 830           not work on models with a Phoenix BIOS. The System Management Mode
 831           is used to set the BIOS and power saving options on Toshiba portables.
 832
 833           For information on utilities to make use of this driver see the
 834           Toshiba Linux utilities web site at:
 835           <http://www.buzzard.org.uk/toshiba/>.
 836
 837           Say Y if you intend to run this kernel on a Toshiba portable.
 838           Say N otherwise.
 839
 840 config I8K
 841         tristate "Dell laptop support"
 842         ---help---
 843           This adds a driver to safely access the System Management Mode
 844           of the CPU on the Dell Inspiron 8000. The System Management Mode
 845           is used to read cpu temperature and cooling fan status and to
 846           control the fans on the I8K portables.
 847
 848           This driver has been tested only on the Inspiron 8000 but it may
 849           also work with other Dell laptops. You can force loading on other
 850           models by passing the parameter `force=1' to the module. Use at
 851           your own risk.
 852
 853           For information on utilities to make use of this driver see the
 854           I8K Linux utilities web site at:
 855           <http://people.debian.org/~dz/i8k/>
 856
 857           Say Y if you intend to run this kernel on a Dell Inspiron 8000.
 858           Say N otherwise.
 859
 860 config X86_REBOOTFIXUPS
 861         bool "Enable X86 board specific fixups for reboot"
 862         depends on X86_32
 863         ---help---
 864           This enables chipset and/or board specific fixups to be done
 865           in order to get reboot to work correctly. This is only needed on
 866           some combinations of hardware and BIOS. The symptom, for which
 867           this config is intended, is when reboot ends with a stalled/hung
 868           system.
 869
 870           Currently, the only fixup is for the Geode machines using
 871           CS5530A and CS5536 chipsets and the RDC R-321x SoC.
 872
 873           Say Y if you want to enable the fixup. Currently, it's safe to
 874           enable this option even if you don't need it.
 875           Say N otherwise.
 876
 877 config MICROCODE
 878         tristate "/dev/cpu/microcode - microcode support"
 879         select FW_LOADER
 880         ---help---
 881           If you say Y here, you will be able to update the microcode on
 882           certain Intel and AMD processors. The Intel support is for the
 883           IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
 884           Pentium 4, Xeon etc. The AMD support is for family 0x10 and
 885           0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
 886           You will obviously need the actual microcode binary data itself
 887           which is not shipped with the Linux kernel.
 888
 889           This option selects the general module only, you need to select
 890           at least one vendor specific module as well.
 891
 892           To compile this driver as a module, choose M here: the
 893           module will be called microcode.
 894
 895 config MICROCODE_INTEL
 896         bool "Intel microcode patch loading support"
 897         depends on MICROCODE
 898         default MICROCODE
 899         select FW_LOADER
 900         ---help---
 901           This options enables microcode patch loading support for Intel
 902           processors.
 903
 904           For latest news and information on obtaining all the required
 905           Intel ingredients for this driver, check:
 906           <http://www.urbanmyth.org/microcode/>.
 907
 908 config MICROCODE_AMD
 909         bool "AMD microcode patch loading support"
 910         depends on MICROCODE
 911         select FW_LOADER
 912         ---help---
 913           If you select this option, microcode patch loading support for AMD
 914           processors will be enabled.
 915
 916 config MICROCODE_OLD_INTERFACE
 917         def_bool y
 918         depends on MICROCODE
 919
 920 config X86_MSR
 921         tristate "/dev/cpu/*/msr - Model-specific register support"
 922         ---help---
 923           This device gives privileged processes access to the x86
 924           Model-Specific Registers (MSRs).  It is a character device with
 925           major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
 926           MSR accesses are directed to a specific CPU on multi-processor
 927           systems.
 928
 929 config X86_CPUID
 930         tristate "/dev/cpu/*/cpuid - CPU information support"
 931         ---help---
 932           This device gives processes access to the x86 CPUID instruction to
 933           be executed on a specific processor.  It is a character device
 934           with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
 935           /dev/cpu/31/cpuid.
 936
 937 config X86_CPU_DEBUG
 938         tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
 939         ---help---
 940           If you select this option, this will provide various x86 CPUs
 941           information through debugfs.
 942
 943 choice
 944         prompt "High Memory Support"
 945         default HIGHMEM4G if !X86_NUMAQ
 946         default HIGHMEM64G if X86_NUMAQ
 947         depends on X86_32
 948
 949 config NOHIGHMEM
 950         bool "off"
 951         depends on !X86_NUMAQ
 952         ---help---
 953           Linux can use up to 64 Gigabytes of physical memory on x86 systems.
 954           However, the address space of 32-bit x86 processors is only 4
 955           Gigabytes large. That means that, if you have a large amount of
 956           physical memory, not all of it can be "permanently mapped" by the
 957           kernel. The physical memory that's not permanently mapped is called
 958           "high memory".
 959
 960           If you are compiling a kernel which will never run on a machine with
 961           more than 1 Gigabyte total physical RAM, answer "off" here (default
 962           choice and suitable for most users). This will result in a "3GB/1GB"
 963           split: 3GB are mapped so that each process sees a 3GB virtual memory
 964           space and the remaining part of the 4GB virtual memory space is used
 965           by the kernel to permanently map as much physical memory as
 966           possible.
 967
 968           If the machine has between 1 and 4 Gigabytes physical RAM, then
 969           answer "4GB" here.
 970
 971           If more than 4 Gigabytes is used then answer "64GB" here. This
 972           selection turns Intel PAE (Physical Address Extension) mode on.
 973           PAE implements 3-level paging on IA32 processors. PAE is fully
 974           supported by Linux, PAE mode is implemented on all recent Intel
 975           processors (Pentium Pro and better). NOTE: If you say "64GB" here,
 976           then the kernel will not boot on CPUs that don't support PAE!
 977
 978           The actual amount of total physical memory will either be
 979           auto detected or can be forced by using a kernel command line option
 980           such as "mem=256M". (Try "man bootparam" or see the documentation of
 981           your boot loader (lilo or loadlin) about how to pass options to the
 982           kernel at boot time.)
 983
 984           If unsure, say "off".
 985
 986 config HIGHMEM4G
 987         bool "4GB"
 988         depends on !X86_NUMAQ
 989         ---help---
 990           Select this if you have a 32-bit processor and between 1 and 4
 991           gigabytes of physical RAM.
 992
 993 config HIGHMEM64G
 994         bool "64GB"
 995         depends on !M386 && !M486
 996         select X86_PAE
 997         ---help---
 998           Select this if you have a 32-bit processor and more than 4
 999           gigabytes of physical RAM.
1000
1001 endchoice
1002
1003 choice
1004         depends on EXPERIMENTAL
1005         prompt "Memory split" if EMBEDDED
1006         default VMSPLIT_3G
1007         depends on X86_32
1008         ---help---
1009           Select the desired split between kernel and user memory.
1010
1011           If the address range available to the kernel is less than the
1012           physical memory installed, the remaining memory will be available
1013           as "high memory". Accessing high memory is a little more costly
1014           than low memory, as it needs to be mapped into the kernel first.
1015           Note that increasing the kernel address space limits the range
1016           available to user programs, making the address space there
1017           tighter.  Selecting anything other than the default 3G/1G split
1018           will also likely make your kernel incompatible with binary-only
1019           kernel modules.
1020
1021           If you are not absolutely sure what you are doing, leave this
1022           option alone!
1023
1024         config VMSPLIT_3G
1025                 bool "3G/1G user/kernel split"
1026         config VMSPLIT_3G_OPT
1027                 depends on !X86_PAE
1028                 bool "3G/1G user/kernel split (for full 1G low memory)"
1029         config VMSPLIT_2G
1030                 bool "2G/2G user/kernel split"
1031         config VMSPLIT_2G_OPT
1032                 depends on !X86_PAE
1033                 bool "2G/2G user/kernel split (for full 2G low memory)"
1034         config VMSPLIT_1G
1035                 bool "1G/3G user/kernel split"
1036 endchoice
1037
1038 config PAGE_OFFSET
1039         hex
1040         default 0xB0000000 if VMSPLIT_3G_OPT
1041         default 0x80000000 if VMSPLIT_2G
1042         default 0x78000000 if VMSPLIT_2G_OPT
1043         default 0x40000000 if VMSPLIT_1G
1044         default 0xC0000000
1045         depends on X86_32
1046
1047 config HIGHMEM
1048         def_bool y
1049         depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1050
1051 config X86_PAE
1052         bool "PAE (Physical Address Extension) Support"
1053         depends on X86_32 && !HIGHMEM4G
1054         ---help---
1055           PAE is required for NX support, and furthermore enables
1056           larger swapspace support for non-overcommit purposes. It
1057           has the cost of more pagetable lookup overhead, and also
1058           consumes more pagetable space per process.
1059
1060 config ARCH_PHYS_ADDR_T_64BIT
1061         def_bool X86_64 || X86_PAE
1062
1063 config DIRECT_GBPAGES
1064         bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1065         default y
1066         depends on X86_64
1067         ---help---
1068           Allow the kernel linear mapping to use 1GB pages on CPUs that
1069           support it. This can improve the kernel's performance a tiny bit by
1070           reducing TLB pressure. If in doubt, say "Y".
1071
1072 # Common NUMA Features
1073 config NUMA
1074         bool "Numa Memory Allocation and Scheduler Support"
1075         depends on SMP
1076         depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1077         default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1078         ---help---
1079           Enable NUMA (Non Uniform Memory Access) support.
1080
1081           The kernel will try to allocate memory used by a CPU on the
1082           local memory controller of the CPU and add some more
1083           NUMA awareness to the kernel.
1084
1085           For 64-bit this is recommended if the system is Intel Core i7
1086           (or later), AMD Opteron, or EM64T NUMA.
1087
1088           For 32-bit this is only needed on (rare) 32-bit-only platforms
1089           that support NUMA topologies, such as NUMAQ / Summit, or if you
1090           boot a 32-bit kernel on a 64-bit NUMA platform.
1091
1092           Otherwise, you should say N.
1093
1094 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1095         depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1096
1097 config K8_NUMA
1098         def_bool y
1099         prompt "Old style AMD Opteron NUMA detection"
1100         depends on X86_64 && NUMA && PCI
1101         ---help---
1102           Enable K8 NUMA node topology detection.  You should say Y here if
1103           you have a multi processor AMD K8 system. This uses an old
1104           method to read the NUMA configuration directly from the builtin
1105           Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1106           instead, which also takes priority if both are compiled in.
1107
1108 config X86_64_ACPI_NUMA
1109         def_bool y
1110         prompt "ACPI NUMA detection"
1111         depends on X86_64 && NUMA && ACPI && PCI
1112         select ACPI_NUMA
1113         ---help---
1114           Enable ACPI SRAT based node topology detection.
1115
1116 # Some NUMA nodes have memory ranges that span
1117 # other nodes.  Even though a pfn is valid and
1118 # between a node's start and end pfns, it may not
1119 # reside on that node.  See memmap_init_zone()
1120 # for details.
1121 config NODES_SPAN_OTHER_NODES
1122         def_bool y
1123         depends on X86_64_ACPI_NUMA
1124
1125 config NUMA_EMU
1126         bool "NUMA emulation"
1127         depends on X86_64 && NUMA
1128         ---help---
1129           Enable NUMA emulation. A flat machine will be split
1130           into virtual nodes when booted with "numa=fake=N", where N is the
1131           number of nodes. This is only useful for debugging.
1132
1133 config NODES_SHIFT
1134         int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1135         range 1 9
1136         default "9" if MAXSMP
1137         default "6" if X86_64
1138         default "4" if X86_NUMAQ
1139         default "3"
1140         depends on NEED_MULTIPLE_NODES
1141         ---help---
1142           Specify the maximum number of NUMA Nodes available on the target
1143           system.  Increases memory reserved to accomodate various tables.
1144
1145 config HAVE_ARCH_BOOTMEM
1146         def_bool y
1147         depends on X86_32 && NUMA
1148
1149 config ARCH_HAVE_MEMORY_PRESENT
1150         def_bool y
1151         depends on X86_32 && DISCONTIGMEM
1152
1153 config NEED_NODE_MEMMAP_SIZE
1154         def_bool y
1155         depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1156
1157 config HAVE_ARCH_ALLOC_REMAP
1158         def_bool y
1159         depends on X86_32 && NUMA
1160
1161 config ARCH_FLATMEM_ENABLE
1162         def_bool y
1163         depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1164
1165 config ARCH_DISCONTIGMEM_ENABLE
1166         def_bool y
1167         depends on NUMA && X86_32
1168
1169 config ARCH_DISCONTIGMEM_DEFAULT
1170         def_bool y
1171         depends on NUMA && X86_32
1172
1173 config ARCH_SPARSEMEM_DEFAULT
1174         def_bool y
1175         depends on X86_64
1176
1177 config ARCH_SPARSEMEM_ENABLE
1178         def_bool y
1179         depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1180         select SPARSEMEM_STATIC if X86_32
1181         select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1182
1183 config ARCH_SELECT_MEMORY_MODEL
1184         def_bool y
1185         depends on ARCH_SPARSEMEM_ENABLE
1186
1187 config ARCH_MEMORY_PROBE
1188         def_bool X86_64
1189         depends on MEMORY_HOTPLUG
1190
1191 source "mm/Kconfig"
1192
1193 config HIGHPTE
1194         bool "Allocate 3rd-level pagetables from highmem"
1195         depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1196         ---help---
1197           The VM uses one page table entry for each page of physical memory.
1198           For systems with a lot of RAM, this can be wasteful of precious
1199           low memory.  Setting this option will put user-space page table
1200           entries in high memory.
1201
1202 config X86_CHECK_BIOS_CORRUPTION
1203         bool "Check for low memory corruption"
1204         ---help---
1205           Periodically check for memory corruption in low memory, which
1206           is suspected to be caused by BIOS.  Even when enabled in the
1207           configuration, it is disabled at runtime.  Enable it by
1208           setting "memory_corruption_check=1" on the kernel command
1209           line.  By default it scans the low 64k of memory every 60
1210           seconds; see the memory_corruption_check_size and
1211           memory_corruption_check_period parameters in
1212           Documentation/kernel-parameters.txt to adjust this.
1213
1214           When enabled with the default parameters, this option has
1215           almost no overhead, as it reserves a relatively small amount
1216           of memory and scans it infrequently.  It both detects corruption
1217           and prevents it from affecting the running system.
1218
1219           It is, however, intended as a diagnostic tool; if repeatable
1220           BIOS-originated corruption always affects the same memory,
1221           you can use memmap= to prevent the kernel from using that
1222           memory.
1223
1224 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1225         bool "Set the default setting of memory_corruption_check"
1226         depends on X86_CHECK_BIOS_CORRUPTION
1227         default y
1228         ---help---
1229           Set whether the default state of memory_corruption_check is
1230           on or off.
1231
1232 config X86_RESERVE_LOW_64K
1233         bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1234         default y
1235         ---help---
1236           Reserve the first 64K of physical RAM on BIOSes that are known
1237           to potentially corrupt that memory range. A numbers of BIOSes are
1238           known to utilize this area during suspend/resume, so it must not
1239           be used by the kernel.
1240
1241           Set this to N if you are absolutely sure that you trust the BIOS
1242           to get all its memory reservations and usages right.
1243
1244           If you have doubts about the BIOS (e.g. suspend/resume does not
1245           work or there's kernel crashes after certain hardware hotplug
1246           events) and it's not AMI or Phoenix, then you might want to enable
1247           X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1248           corruption patterns.
1249
1250           Say Y if unsure.
1251
1252 config MATH_EMULATION
1253         bool
1254         prompt "Math emulation" if X86_32
1255         ---help---
1256           Linux can emulate a math coprocessor (used for floating point
1257           operations) if you don't have one. 486DX and Pentium processors have
1258           a math coprocessor built in, 486SX and 386 do not, unless you added
1259           a 487DX or 387, respectively. (The messages during boot time can
1260           give you some hints here ["man dmesg"].) Everyone needs either a
1261           coprocessor or this emulation.
1262
1263           If you don't have a math coprocessor, you need to say Y here; if you
1264           say Y here even though you have a coprocessor, the coprocessor will
1265           be used nevertheless. (This behavior can be changed with the kernel
1266           command line option "no387", which comes handy if your coprocessor
1267           is broken. Try "man bootparam" or see the documentation of your boot
1268           loader (lilo or loadlin) about how to pass options to the kernel at
1269           boot time.) This means that it is a good idea to say Y here if you
1270           intend to use this kernel on different machines.
1271
1272           More information about the internals of the Linux math coprocessor
1273           emulation can be found in <file:arch/x86/math-emu/README>.
1274
1275           If you are not sure, say Y; apart from resulting in a 66 KB bigger
1276           kernel, it won't hurt.
1277
1278 config MTRR
1279         bool "MTRR (Memory Type Range Register) support"
1280         ---help---
1281           On Intel P6 family processors (Pentium Pro, Pentium II and later)
1282           the Memory Type Range Registers (MTRRs) may be used to control
1283           processor access to memory ranges. This is most useful if you have
1284           a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1285           allows bus write transfers to be combined into a larger transfer
1286           before bursting over the PCI/AGP bus. This can increase performance
1287           of image write operations 2.5 times or more. Saying Y here creates a
1288           /proc/mtrr file which may be used to manipulate your processor's
1289           MTRRs. Typically the X server should use this.
1290
1291           This code has a reasonably generic interface so that similar
1292           control registers on other processors can be easily supported
1293           as well:
1294
1295           The Cyrix 6x86, 6x86MX and M II processors have Address Range
1296           Registers (ARRs) which provide a similar functionality to MTRRs. For
1297           these, the ARRs are used to emulate the MTRRs.
1298           The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1299           MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1300           write-combining. All of these processors are supported by this code
1301           and it makes sense to say Y here if you have one of them.
1302
1303           Saying Y here also fixes a problem with buggy SMP BIOSes which only
1304           set the MTRRs for the boot CPU and not for the secondary CPUs. This
1305           can lead to all sorts of problems, so it's good to say Y here.
1306
1307           You can safely say Y even if your machine doesn't have MTRRs, you'll
1308           just add about 9 KB to your kernel.
1309
1310           See <file:Documentation/x86/mtrr.txt> for more information.
1311
1312 config MTRR_SANITIZER
1313         def_bool y
1314         prompt "MTRR cleanup support"
1315         depends on MTRR
1316         ---help---
1317           Convert MTRR layout from continuous to discrete, so X drivers can
1318           add writeback entries.
1319
1320           Can be disabled with disable_mtrr_cleanup on the kernel command line.
1321           The largest mtrr entry size for a continous block can be set with
1322           mtrr_chunk_size.
1323
1324           If unsure, say Y.
1325
1326 config MTRR_SANITIZER_ENABLE_DEFAULT
1327         int "MTRR cleanup enable value (0-1)"
1328         range 0 1
1329         default "0"
1330         depends on MTRR_SANITIZER
1331         ---help---
1332           Enable mtrr cleanup default value
1333
1334 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1335         int "MTRR cleanup spare reg num (0-7)"
1336         range 0 7
1337         default "1"
1338         depends on MTRR_SANITIZER
1339         ---help---
1340           mtrr cleanup spare entries default, it can be changed via
1341           mtrr_spare_reg_nr=N on the kernel command line.
1342
1343 config X86_PAT
1344         bool
1345         prompt "x86 PAT support"
1346         depends on MTRR
1347         ---help---
1348           Use PAT attributes to setup page level cache control.
1349
1350           PATs are the modern equivalents of MTRRs and are much more
1351           flexible than MTRRs.
1352
1353           Say N here if you see bootup problems (boot crash, boot hang,
1354           spontaneous reboots) or a non-working video driver.
1355
1356           If unsure, say Y.
1357
1358 config EFI
1359         bool "EFI runtime service support"
1360         depends on ACPI
1361         ---help---
1362           This enables the kernel to use EFI runtime services that are
1363           available (such as the EFI variable services).
1364
1365           This option is only useful on systems that have EFI firmware.
1366           In addition, you should use the latest ELILO loader available
1367           at <http://elilo.sourceforge.net> in order to take advantage
1368           of EFI runtime services. However, even with this option, the
1369           resultant kernel should continue to boot on existing non-EFI
1370           platforms.
1371
1372 config SECCOMP
1373         def_bool y
1374         prompt "Enable seccomp to safely compute untrusted bytecode"
1375         ---help---
1376           This kernel feature is useful for number crunching applications
1377           that may need to compute untrusted bytecode during their
1378           execution. By using pipes or other transports made available to
1379           the process as file descriptors supporting the read/write
1380           syscalls, it's possible to isolate those applications in
1381           their own address space using seccomp. Once seccomp is
1382           enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1383           and the task is only allowed to execute a few safe syscalls
1384           defined by each seccomp mode.
1385
1386           If unsure, say Y. Only embedded should say N here.
1387
1388 config CC_STACKPROTECTOR_ALL
1389         bool
1390
1391 config CC_STACKPROTECTOR
1392         bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1393         select CC_STACKPROTECTOR_ALL
1394         ---help---
1395           This option turns on the -fstack-protector GCC feature. This
1396           feature puts, at the beginning of functions, a canary value on
1397           the stack just before the return address, and validates
1398           the value just before actually returning.  Stack based buffer
1399           overflows (that need to overwrite this return address) now also
1400           overwrite the canary, which gets detected and the attack is then
1401           neutralized via a kernel panic.
1402
1403           This feature requires gcc version 4.2 or above, or a distribution
1404           gcc with the feature backported. Older versions are automatically
1405           detected and for those versions, this configuration option is
1406           ignored. (and a warning is printed during bootup)
1407
1408 source kernel/Kconfig.hz
1409
1410 config KEXEC
1411         bool "kexec system call"
1412         ---help---
1413           kexec is a system call that implements the ability to shutdown your
1414           current kernel, and to start another kernel.  It is like a reboot
1415           but it is independent of the system firmware.   And like a reboot
1416           you can start any kernel with it, not just Linux.
1417
1418           The name comes from the similarity to the exec system call.
1419
1420           It is an ongoing process to be certain the hardware in a machine
1421           is properly shutdown, so do not be surprised if this code does not
1422           initially work for you.  It may help to enable device hotplugging
1423           support.  As of this writing the exact hardware interface is
1424           strongly in flux, so no good recommendation can be made.
1425
1426 config CRASH_DUMP
1427         bool "kernel crash dumps"
1428         depends on X86_64 || (X86_32 && HIGHMEM)
1429         ---help---
1430           Generate crash dump after being started by kexec.
1431           This should be normally only set in special crash dump kernels
1432           which are loaded in the main kernel with kexec-tools into
1433           a specially reserved region and then later executed after
1434           a crash by kdump/kexec. The crash dump kernel must be compiled
1435           to a memory address not used by the main kernel or BIOS using
1436           PHYSICAL_START, or it must be built as a relocatable image
1437           (CONFIG_RELOCATABLE=y).
1438           For more details see Documentation/kdump/kdump.txt
1439
1440 config KEXEC_JUMP
1441         bool "kexec jump (EXPERIMENTAL)"
1442         depends on EXPERIMENTAL
1443         depends on KEXEC && HIBERNATION
1444         ---help---
1445           Jump between original kernel and kexeced kernel and invoke
1446           code in physical address mode via KEXEC
1447
1448 config PHYSICAL_START
1449         hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1450         default "0x1000000" if X86_NUMAQ
1451         default "0x200000" if X86_64
1452         default "0x100000"
1453         ---help---
1454           This gives the physical address where the kernel is loaded.
1455
1456           If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1457           bzImage will decompress itself to above physical address and
1458           run from there. Otherwise, bzImage will run from the address where
1459           it has been loaded by the boot loader and will ignore above physical
1460           address.
1461
1462           In normal kdump cases one does not have to set/change this option
1463           as now bzImage can be compiled as a completely relocatable image
1464           (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1465           address. This option is mainly useful for the folks who don't want
1466           to use a bzImage for capturing the crash dump and want to use a
1467           vmlinux instead. vmlinux is not relocatable hence a kernel needs
1468           to be specifically compiled to run from a specific memory area
1469           (normally a reserved region) and this option comes handy.
1470
1471           So if you are using bzImage for capturing the crash dump, leave
1472           the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1473           Otherwise if you plan to use vmlinux for capturing the crash dump
1474           change this value to start of the reserved region (Typically 16MB
1475           0x1000000). In other words, it can be set based on the "X" value as
1476           specified in the "crashkernel=YM@XM" command line boot parameter
1477           passed to the panic-ed kernel. Typically this parameter is set as
1478           crashkernel=64M@16M. Please take a look at
1479           Documentation/kdump/kdump.txt for more details about crash dumps.
1480
1481           Usage of bzImage for capturing the crash dump is recommended as
1482           one does not have to build two kernels. Same kernel can be used
1483           as production kernel and capture kernel. Above option should have
1484           gone away after relocatable bzImage support is introduced. But it
1485           is present because there are users out there who continue to use
1486           vmlinux for dump capture. This option should go away down the
1487           line.
1488
1489           Don't change this unless you know what you are doing.
1490
1491 config RELOCATABLE
1492         bool "Build a relocatable kernel (EXPERIMENTAL)"
1493         depends on EXPERIMENTAL
1494         ---help---
1495           This builds a kernel image that retains relocation information
1496           so it can be loaded someplace besides the default 1MB.
1497           The relocations tend to make the kernel binary about 10% larger,
1498           but are discarded at runtime.
1499
1500           One use is for the kexec on panic case where the recovery kernel
1501           must live at a different physical address than the primary
1502           kernel.
1503
1504           Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1505           it has been loaded at and the compile time physical address
1506           (CONFIG_PHYSICAL_START) is ignored.
1507
1508 config PHYSICAL_ALIGN
1509         hex
1510         prompt "Alignment value to which kernel should be aligned" if X86_32
1511         default "0x100000" if X86_32
1512         default "0x200000" if X86_64
1513         range 0x2000 0x400000
1514         ---help---
1515           This value puts the alignment restrictions on physical address
1516           where kernel is loaded and run from. Kernel is compiled for an
1517           address which meets above alignment restriction.
1518
1519           If bootloader loads the kernel at a non-aligned address and
1520           CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1521           address aligned to above value and run from there.
1522
1523           If bootloader loads the kernel at a non-aligned address and
1524           CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1525           load address and decompress itself to the address it has been
1526           compiled for and run from there. The address for which kernel is
1527           compiled already meets above alignment restrictions. Hence the
1528           end result is that kernel runs from a physical address meeting
1529           above alignment restrictions.
1530
1531           Don't change this unless you know what you are doing.
1532
1533 config HOTPLUG_CPU
1534         bool "Support for hot-pluggable CPUs"
1535         depends on SMP && HOTPLUG
1536         ---help---
1537           Say Y here to allow turning CPUs off and on. CPUs can be
1538           controlled through /sys/devices/system/cpu.
1539           ( Note: power management support will enable this option
1540             automatically on SMP systems. )
1541           Say N if you want to disable CPU hotplug.
1542
1543 config COMPAT_VDSO
1544         def_bool y
1545         prompt "Compat VDSO support"
1546         depends on X86_32 || IA32_EMULATION
1547         ---help---
1548           Map the 32-bit VDSO to the predictable old-style address too.
1549         ---help---
1550           Say N here if you are running a sufficiently recent glibc
1551           version (2.3.3 or later), to remove the high-mapped
1552           VDSO mapping and to exclusively use the randomized VDSO.
1553
1554           If unsure, say Y.
1555
1556 config CMDLINE_BOOL
1557         bool "Built-in kernel command line"
1558         default n
1559         ---help---
1560           Allow for specifying boot arguments to the kernel at
1561           build time.  On some systems (e.g. embedded ones), it is
1562           necessary or convenient to provide some or all of the
1563           kernel boot arguments with the kernel itself (that is,
1564           to not rely on the boot loader to provide them.)
1565
1566           To compile command line arguments into the kernel,
1567           set this option to 'Y', then fill in the
1568           the boot arguments in CONFIG_CMDLINE.
1569
1570           Systems with fully functional boot loaders (i.e. non-embedded)
1571           should leave this option set to 'N'.
1572
1573 config CMDLINE
1574         string "Built-in kernel command string"
1575         depends on CMDLINE_BOOL
1576         default ""
1577         ---help---
1578           Enter arguments here that should be compiled into the kernel
1579           image and used at boot time.  If the boot loader provides a
1580           command line at boot time, it is appended to this string to
1581           form the full kernel command line, when the system boots.
1582
1583           However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1584           change this behavior.
1585
1586           In most cases, the command line (whether built-in or provided
1587           by the boot loader) should specify the device for the root
1588           file system.
1589
1590 config CMDLINE_OVERRIDE
1591         bool "Built-in command line overrides boot loader arguments"
1592         default n
1593         depends on CMDLINE_BOOL
1594         ---help---
1595           Set this option to 'Y' to have the kernel ignore the boot loader
1596           command line, and use ONLY the built-in command line.
1597
1598           This is used to work around broken boot loaders.  This should
1599           be set to 'N' under normal conditions.
1600
1601 endmenu
1602
1603 config ARCH_ENABLE_MEMORY_HOTPLUG
1604         def_bool y
1605         depends on X86_64 || (X86_32 && HIGHMEM)
1606
1607 config ARCH_ENABLE_MEMORY_HOTREMOVE
1608         def_bool y
1609         depends on MEMORY_HOTPLUG
1610
1611 config HAVE_ARCH_EARLY_PFN_TO_NID
1612         def_bool X86_64
1613         depends on NUMA
1614
1615 menu "Power management and ACPI options"
1616
1617 config ARCH_HIBERNATION_HEADER
1618         def_bool y
1619         depends on X86_64 && HIBERNATION
1620
1621 source "kernel/power/Kconfig"
1622
1623 source "drivers/acpi/Kconfig"
1624
1625 config X86_APM_BOOT
1626         bool
1627         default y
1628         depends on APM || APM_MODULE
1629
1630 menuconfig APM
1631         tristate "APM (Advanced Power Management) BIOS support"
1632         depends on X86_32 && PM_SLEEP
1633         ---help---
1634           APM is a BIOS specification for saving power using several different
1635           techniques. This is mostly useful for battery powered laptops with
1636           APM compliant BIOSes. If you say Y here, the system time will be
1637           reset after a RESUME operation, the /proc/apm device will provide
1638           battery status information, and user-space programs will receive
1639           notification of APM "events" (e.g. battery status change).
1640
1641           If you select "Y" here, you can disable actual use of the APM
1642           BIOS by passing the "apm=off" option to the kernel at boot time.
1643
1644           Note that the APM support is almost completely disabled for
1645           machines with more than one CPU.
1646
1647           In order to use APM, you will need supporting software. For location
1648           and more information, read <file:Documentation/power/pm.txt> and the
1649           Battery Powered Linux mini-HOWTO, available from
1650           <http://www.tldp.org/docs.html#howto>.
1651
1652           This driver does not spin down disk drives (see the hdparm(8)
1653           manpage ("man 8 hdparm") for that), and it doesn't turn off
1654           VESA-compliant "green" monitors.
1655
1656           This driver does not support the TI 4000M TravelMate and the ACER
1657           486/DX4/75 because they don't have compliant BIOSes. Many "green"
1658           desktop machines also don't have compliant BIOSes, and this driver
1659           may cause those machines to panic during the boot phase.
1660
1661           Generally, if you don't have a battery in your machine, there isn't
1662           much point in using this driver and you should say N. If you get
1663           random kernel OOPSes or reboots that don't seem to be related to
1664           anything, try disabling/enabling this option (or disabling/enabling
1665           APM in your BIOS).
1666
1667           Some other things you should try when experiencing seemingly random,
1668           "weird" problems:
1669
1670           1) make sure that you have enough swap space and that it is
1671           enabled.
1672           2) pass the "no-hlt" option to the kernel
1673           3) switch on floating point emulation in the kernel and pass
1674           the "no387" option to the kernel
1675           4) pass the "floppy=nodma" option to the kernel
1676           5) pass the "mem=4M" option to the kernel (thereby disabling
1677           all but the first 4 MB of RAM)
1678           6) make sure that the CPU is not over clocked.
1679           7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1680           8) disable the cache from your BIOS settings
1681           9) install a fan for the video card or exchange video RAM
1682           10) install a better fan for the CPU
1683           11) exchange RAM chips
1684           12) exchange the motherboard.
1685
1686           To compile this driver as a module, choose M here: the
1687           module will be called apm.
1688
1689 if APM
1690
1691 config APM_IGNORE_USER_SUSPEND
1692         bool "Ignore USER SUSPEND"
1693         ---help---
1694           This option will ignore USER SUSPEND requests. On machines with a
1695           compliant APM BIOS, you want to say N. However, on the NEC Versa M
1696           series notebooks, it is necessary to say Y because of a BIOS bug.
1697
1698 config APM_DO_ENABLE
1699         bool "Enable PM at boot time"
1700         ---help---
1701           Enable APM features at boot time. From page 36 of the APM BIOS
1702           specification: "When disabled, the APM BIOS does not automatically
1703           power manage devices, enter the Standby State, enter the Suspend
1704           State, or take power saving steps in response to CPU Idle calls."
1705           This driver will make CPU Idle calls when Linux is idle (unless this
1706           feature is turned off -- see "Do CPU IDLE calls", below). This
1707           should always save battery power, but more complicated APM features
1708           will be dependent on your BIOS implementation. You may need to turn
1709           this option off if your computer hangs at boot time when using APM
1710           support, or if it beeps continuously instead of suspending. Turn
1711           this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1712           T400CDT. This is off by default since most machines do fine without
1713           this feature.
1714
1715 config APM_CPU_IDLE
1716         bool "Make CPU Idle calls when idle"
1717         ---help---
1718           Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1719           On some machines, this can activate improved power savings, such as
1720           a slowed CPU clock rate, when the machine is idle. These idle calls
1721           are made after the idle loop has run for some length of time (e.g.,
1722           333 mS). On some machines, this will cause a hang at boot time or
1723           whenever the CPU becomes idle. (On machines with more than one CPU,
1724           this option does nothing.)
1725
1726 config APM_DISPLAY_BLANK
1727         bool "Enable console blanking using APM"
1728         ---help---
1729           Enable console blanking using the APM. Some laptops can use this to
1730           turn off the LCD backlight when the screen blanker of the Linux
1731           virtual console blanks the screen. Note that this is only used by
1732           the virtual console screen blanker, and won't turn off the backlight
1733           when using the X Window system. This also doesn't have anything to
1734           do with your VESA-compliant power-saving monitor. Further, this
1735           option doesn't work for all laptops -- it might not turn off your
1736           backlight at all, or it might print a lot of errors to the console,
1737           especially if you are using gpm.
1738
1739 config APM_ALLOW_INTS
1740         bool "Allow interrupts during APM BIOS calls"
1741         ---help---
1742           Normally we disable external interrupts while we are making calls to
1743           the APM BIOS as a measure to lessen the effects of a badly behaving
1744           BIOS implementation.  The BIOS should reenable interrupts if it
1745           needs to.  Unfortunately, some BIOSes do not -- especially those in
1746           many of the newer IBM Thinkpads.  If you experience hangs when you
1747           suspend, try setting this to Y.  Otherwise, say N.
1748
1749 endif # APM
1750
1751 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1752
1753 source "drivers/cpuidle/Kconfig"
1754
1755 source "drivers/idle/Kconfig"
1756
1757 endmenu
1758
1759
1760 menu "Bus options (PCI etc.)"
1761
1762 config PCI
1763         bool "PCI support"
1764         default y
1765         select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1766         ---help---
1767           Find out whether you have a PCI motherboard. PCI is the name of a
1768           bus system, i.e. the way the CPU talks to the other stuff inside
1769           your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1770           VESA. If you have PCI, say Y, otherwise N.
1771
1772 choice
1773         prompt "PCI access mode"
1774         depends on X86_32 && PCI
1775         default PCI_GOANY
1776         ---help---
1777           On PCI systems, the BIOS can be used to detect the PCI devices and
1778           determine their configuration. However, some old PCI motherboards
1779           have BIOS bugs and may crash if this is done. Also, some embedded
1780           PCI-based systems don't have any BIOS at all. Linux can also try to
1781           detect the PCI hardware directly without using the BIOS.
1782
1783           With this option, you can specify how Linux should detect the
1784           PCI devices. If you choose "BIOS", the BIOS will be used,
1785           if you choose "Direct", the BIOS won't be used, and if you
1786           choose "MMConfig", then PCI Express MMCONFIG will be used.
1787           If you choose "Any", the kernel will try MMCONFIG, then the
1788           direct access method and falls back to the BIOS if that doesn't
1789           work. If unsure, go with the default, which is "Any".
1790
1791 config PCI_GOBIOS
1792         bool "BIOS"
1793
1794 config PCI_GOMMCONFIG
1795         bool "MMConfig"
1796
1797 config PCI_GODIRECT
1798         bool "Direct"
1799
1800 config PCI_GOOLPC
1801         bool "OLPC"
1802         depends on OLPC
1803
1804 config PCI_GOANY
1805         bool "Any"
1806
1807 endchoice
1808
1809 config PCI_BIOS
1810         def_bool y
1811         depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1812
1813 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1814 config PCI_DIRECT
1815         def_bool y
1816         depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1817
1818 config PCI_MMCONFIG
1819         def_bool y
1820         depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1821
1822 config PCI_OLPC
1823         def_bool y
1824         depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1825
1826 config PCI_DOMAINS
1827         def_bool y
1828         depends on PCI
1829
1830 config PCI_MMCONFIG
1831         bool "Support mmconfig PCI config space access"
1832         depends on X86_64 && PCI && ACPI
1833
1834 config DMAR
1835         bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1836         depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1837         ---help---
1838           DMA remapping (DMAR) devices support enables independent address
1839           translations for Direct Memory Access (DMA) from devices.
1840           These DMA remapping devices are reported via ACPI tables
1841           and include PCI device scope covered by these DMA
1842           remapping devices.
1843
1844 config DMAR_DEFAULT_ON
1845         def_bool y
1846         prompt "Enable DMA Remapping Devices by default"
1847         depends on DMAR
1848         help
1849           Selecting this option will enable a DMAR device at boot time if
1850           one is found. If this option is not selected, DMAR support can
1851           be enabled by passing intel_iommu=on to the kernel. It is
1852           recommended you say N here while the DMAR code remains
1853           experimental.
1854
1855 config DMAR_GFX_WA
1856         def_bool y
1857         prompt "Support for Graphics workaround"
1858         depends on DMAR
1859         ---help---
1860           Current Graphics drivers tend to use physical address
1861           for DMA and avoid using DMA APIs. Setting this config
1862           option permits the IOMMU driver to set a unity map for
1863           all the OS-visible memory. Hence the driver can continue
1864           to use physical addresses for DMA.
1865
1866 config DMAR_FLOPPY_WA
1867         def_bool y
1868         depends on DMAR
1869         ---help---
1870           Floppy disk drivers are know to bypass DMA API calls
1871           thereby failing to work when IOMMU is enabled. This
1872           workaround will setup a 1:1 mapping for the first
1873           16M to make floppy (an ISA device) work.
1874
1875 config INTR_REMAP
1876         bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1877         depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1878         select X86_X2APIC
1879         ---help---
1880           Supports Interrupt remapping for IO-APIC and MSI devices.
1881           To use x2apic mode in the CPU's which support x2APIC enhancements or
1882           to support platforms with CPU's having > 8 bit APIC ID, say Y.
1883
1884 source "drivers/pci/pcie/Kconfig"
1885
1886 source "drivers/pci/Kconfig"
1887
1888 # x86_64 have no ISA slots, but do have ISA-style DMA.
1889 config ISA_DMA_API
1890         def_bool y
1891
1892 if X86_32
1893
1894 config ISA
1895         bool "ISA support"
1896         ---help---
1897           Find out whether you have ISA slots on your motherboard.  ISA is the
1898           name of a bus system, i.e. the way the CPU talks to the other stuff
1899           inside your box.  Other bus systems are PCI, EISA, MicroChannel
1900           (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
1901           newer boards don't support it.  If you have ISA, say Y, otherwise N.
1902
1903 config EISA
1904         bool "EISA support"
1905         depends on ISA
1906         ---help---
1907           The Extended Industry Standard Architecture (EISA) bus was
1908           developed as an open alternative to the IBM MicroChannel bus.
1909
1910           The EISA bus provided some of the features of the IBM MicroChannel
1911           bus while maintaining backward compatibility with cards made for
1912           the older ISA bus.  The EISA bus saw limited use between 1988 and
1913           1995 when it was made obsolete by the PCI bus.
1914
1915           Say Y here if you are building a kernel for an EISA-based machine.
1916
1917           Otherwise, say N.
1918
1919 source "drivers/eisa/Kconfig"
1920
1921 config MCA
1922         bool "MCA support"
1923         ---help---
1924           MicroChannel Architecture is found in some IBM PS/2 machines and
1925           laptops.  It is a bus system similar to PCI or ISA. See
1926           <file:Documentation/mca.txt> (and especially the web page given
1927           there) before attempting to build an MCA bus kernel.
1928
1929 source "drivers/mca/Kconfig"
1930
1931 config SCx200
1932         tristate "NatSemi SCx200 support"
1933         ---help---
1934           This provides basic support for National Semiconductor's
1935           (now AMD's) Geode processors.  The driver probes for the
1936           PCI-IDs of several on-chip devices, so its a good dependency
1937           for other scx200_* drivers.
1938
1939           If compiled as a module, the driver is named scx200.
1940
1941 config SCx200HR_TIMER
1942         tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1943         depends on SCx200 && GENERIC_TIME
1944         default y
1945         ---help---
1946           This driver provides a clocksource built upon the on-chip
1947           27MHz high-resolution timer.  Its also a workaround for
1948           NSC Geode SC-1100's buggy TSC, which loses time when the
1949           processor goes idle (as is done by the scheduler).  The
1950           other workaround is idle=poll boot option.
1951
1952 config GEODE_MFGPT_TIMER
1953         def_bool y
1954         prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1955         depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1956         ---help---
1957           This driver provides a clock event source based on the MFGPT
1958           timer(s) in the CS5535 and CS5536 companion chip for the geode.
1959           MFGPTs have a better resolution and max interval than the
1960           generic PIT, and are suitable for use as high-res timers.
1961
1962 config OLPC
1963         bool "One Laptop Per Child support"
1964         default n
1965         ---help---
1966           Add support for detecting the unique features of the OLPC
1967           XO hardware.
1968
1969 endif # X86_32
1970
1971 config K8_NB
1972         def_bool y
1973         depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1974
1975 source "drivers/pcmcia/Kconfig"
1976
1977 source "drivers/pci/hotplug/Kconfig"
1978
1979 endmenu
1980
1981
1982 menu "Executable file formats / Emulations"
1983
1984 source "fs/Kconfig.binfmt"
1985
1986 config IA32_EMULATION
1987         bool "IA32 Emulation"
1988         depends on X86_64
1989         select COMPAT_BINFMT_ELF
1990         ---help---
1991           Include code to run 32-bit programs under a 64-bit kernel. You should
1992           likely turn this on, unless you're 100% sure that you don't have any
1993           32-bit programs left.
1994
1995 config IA32_AOUT
1996         tristate "IA32 a.out support"
1997         depends on IA32_EMULATION
1998         ---help---
1999           Support old a.out binaries in the 32bit emulation.
2000
2001 config COMPAT
2002         def_bool y
2003         depends on IA32_EMULATION
2004
2005 config COMPAT_FOR_U64_ALIGNMENT
2006         def_bool COMPAT
2007         depends on X86_64
2008
2009 config SYSVIPC_COMPAT
2010         def_bool y
2011         depends on COMPAT && SYSVIPC
2012
2013 endmenu
2014
2015
2016 config HAVE_ATOMIC_IOMAP
2017         def_bool y
2018         depends on X86_32
2019
2020 source "net/Kconfig"
2021
2022 source "drivers/Kconfig"
2023
2024 source "drivers/firmware/Kconfig"
2025
2026 source "fs/Kconfig"
2027
2028 source "arch/x86/Kconfig.debug"
2029
2030 source "security/Kconfig"
2031
2032 source "crypto/Kconfig"
2033
2034 source "arch/x86/kvm/Kconfig"
2035
2036 source "lib/Kconfig"