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_PERF_COUNTERS if (!M386 && !M486)
  28         select HAVE_IOREMAP_PROT
  29         select HAVE_KPROBES
  30         select ARCH_WANT_OPTIONAL_GPIOLIB
  31         select ARCH_WANT_FRAME_POINTERS
  32         select HAVE_DMA_ATTRS
  33         select HAVE_KRETPROBES
  34         select HAVE_FTRACE_MCOUNT_RECORD
  35         select HAVE_DYNAMIC_FTRACE
  36         select HAVE_FUNCTION_TRACER
  37         select HAVE_FUNCTION_GRAPH_TRACER
  38         select HAVE_FUNCTION_GRAPH_FP_TEST
  39         select HAVE_FUNCTION_TRACE_MCOUNT_TEST
  40         select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
  41         select HAVE_SYSCALL_TRACEPOINTS
  42         select HAVE_KVM
  43         select HAVE_ARCH_KGDB
  44         select HAVE_ARCH_TRACEHOOK
  45         select HAVE_GENERIC_DMA_COHERENT if X86_32
  46         select HAVE_EFFICIENT_UNALIGNED_ACCESS
  47         select USER_STACKTRACE_SUPPORT
  48         select HAVE_DMA_API_DEBUG
  49         select HAVE_KERNEL_GZIP
  50         select HAVE_KERNEL_BZIP2
  51         select HAVE_KERNEL_LZMA
  52         select HAVE_ARCH_KMEMCHECK
  53
  54 config OUTPUT_FORMAT
  55         string
  56         default "elf32-i386" if X86_32
  57         default "elf64-x86-64" if X86_64
  58
  59 config ARCH_DEFCONFIG
  60         string
  61         default "arch/x86/configs/i386_defconfig" if X86_32
  62         default "arch/x86/configs/x86_64_defconfig" if X86_64
  63
  64 config GENERIC_TIME
  65         def_bool y
  66
  67 config GENERIC_CMOS_UPDATE
  68         def_bool y
  69
  70 config CLOCKSOURCE_WATCHDOG
  71         def_bool y
  72
  73 config GENERIC_CLOCKEVENTS
  74         def_bool y
  75
  76 config GENERIC_CLOCKEVENTS_BROADCAST
  77         def_bool y
  78         depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
  79
  80 config LOCKDEP_SUPPORT
  81         def_bool y
  82
  83 config STACKTRACE_SUPPORT
  84         def_bool y
  85
  86 config HAVE_LATENCYTOP_SUPPORT
  87         def_bool y
  88
  89 config FAST_CMPXCHG_LOCAL
  90         bool
  91         default y
  92
  93 config MMU
  94         def_bool y
  95
  96 config ZONE_DMA
  97         def_bool y
  98
  99 config SBUS
 100         bool
 101
 102 config GENERIC_ISA_DMA
 103         def_bool y
 104
 105 config GENERIC_IOMAP
 106         def_bool y
 107
 108 config GENERIC_BUG
 109         def_bool y
 110         depends on BUG
 111         select GENERIC_BUG_RELATIVE_POINTERS if X86_64
 112
 113 config GENERIC_BUG_RELATIVE_POINTERS
 114         bool
 115
 116 config GENERIC_HWEIGHT
 117         def_bool y
 118
 119 config GENERIC_GPIO
 120         bool
 121
 122 config ARCH_MAY_HAVE_PC_FDC
 123         def_bool y
 124
 125 config RWSEM_GENERIC_SPINLOCK
 126         def_bool !X86_XADD
 127
 128 config RWSEM_XCHGADD_ALGORITHM
 129         def_bool X86_XADD
 130
 131 config ARCH_HAS_CPU_IDLE_WAIT
 132         def_bool y
 133
 134 config GENERIC_CALIBRATE_DELAY
 135         def_bool y
 136
 137 config GENERIC_TIME_VSYSCALL
 138         bool
 139         default X86_64
 140
 141 config ARCH_HAS_CPU_RELAX
 142         def_bool y
 143
 144 config ARCH_HAS_DEFAULT_IDLE
 145         def_bool y
 146
 147 config ARCH_HAS_CACHE_LINE_SIZE
 148         def_bool y
 149
 150 config HAVE_SETUP_PER_CPU_AREA
 151         def_bool y
 152
 153 config NEED_PER_CPU_EMBED_FIRST_CHUNK
 154         def_bool y
 155
 156 config NEED_PER_CPU_PAGE_FIRST_CHUNK
 157         def_bool y
 158
 159 config HAVE_CPUMASK_OF_CPU_MAP
 160         def_bool X86_64_SMP
 161
 162 config ARCH_HIBERNATION_POSSIBLE
 163         def_bool y
 164
 165 config ARCH_SUSPEND_POSSIBLE
 166         def_bool y
 167
 168 config ZONE_DMA32
 169         bool
 170         default X86_64
 171
 172 config ARCH_POPULATES_NODE_MAP
 173         def_bool y
 174
 175 config AUDIT_ARCH
 176         bool
 177         default X86_64
 178
 179 config ARCH_SUPPORTS_OPTIMIZED_INLINING
 180         def_bool y
 181
 182 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
 183         def_bool y
 184
 185 config HAVE_INTEL_TXT
 186         def_bool y
 187         depends on EXPERIMENTAL && DMAR && ACPI
 188
 189 # Use the generic interrupt handling code in kernel/irq/:
 190 config GENERIC_HARDIRQS
 191         bool
 192         default y
 193
 194 config GENERIC_HARDIRQS_NO__DO_IRQ
 195        def_bool y
 196
 197 config GENERIC_IRQ_PROBE
 198         bool
 199         default y
 200
 201 config GENERIC_PENDING_IRQ
 202         bool
 203         depends on GENERIC_HARDIRQS && SMP
 204         default y
 205
 206 config USE_GENERIC_SMP_HELPERS
 207         def_bool y
 208         depends on SMP
 209
 210 config X86_32_SMP
 211         def_bool y
 212         depends on X86_32 && SMP
 213
 214 config X86_64_SMP
 215         def_bool y
 216         depends on X86_64 && SMP
 217
 218 config X86_HT
 219         bool
 220         depends on SMP
 221         default y
 222
 223 config X86_TRAMPOLINE
 224         bool
 225         depends on SMP || (64BIT && ACPI_SLEEP)
 226         default y
 227
 228 config X86_32_LAZY_GS
 229         def_bool y
 230         depends on X86_32 && !CC_STACKPROTECTOR
 231
 232 config KTIME_SCALAR
 233         def_bool X86_32
 234 source "init/Kconfig"
 235 source "kernel/Kconfig.freezer"
 236
 237 menu "Processor type and features"
 238
 239 source "kernel/time/Kconfig"
 240
 241 config SMP
 242         bool "Symmetric multi-processing support"
 243         ---help---
 244           This enables support for systems with more than one CPU. If you have
 245           a system with only one CPU, like most personal computers, say N. If
 246           you have a system with more than one CPU, say Y.
 247
 248           If you say N here, the kernel will run on single and multiprocessor
 249           machines, but will use only one CPU of a multiprocessor machine. If
 250           you say Y here, the kernel will run on many, but not all,
 251           singleprocessor machines. On a singleprocessor machine, the kernel
 252           will run faster if you say N here.
 253
 254           Note that if you say Y here and choose architecture "586" or
 255           "Pentium" under "Processor family", the kernel will not work on 486
 256           architectures. Similarly, multiprocessor kernels for the "PPro"
 257           architecture may not work on all Pentium based boards.
 258
 259           People using multiprocessor machines who say Y here should also say
 260           Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
 261           Management" code will be disabled if you say Y here.
 262
 263           See also <file:Documentation/i386/IO-APIC.txt>,
 264           <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
 265           <http://www.tldp.org/docs.html#howto>.
 266
 267           If you don't know what to do here, say N.
 268
 269 config X86_X2APIC
 270         bool "Support x2apic"
 271         depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
 272         ---help---
 273           This enables x2apic support on CPUs that have this feature.
 274
 275           This allows 32-bit apic IDs (so it can support very large systems),
 276           and accesses the local apic via MSRs not via mmio.
 277
 278           If you don't know what to do here, say N.
 279
 280 config SPARSE_IRQ
 281         bool "Support sparse irq numbering"
 282         depends on PCI_MSI || HT_IRQ
 283         ---help---
 284           This enables support for sparse irqs. This is useful for distro
 285           kernels that want to define a high CONFIG_NR_CPUS value but still
 286           want to have low kernel memory footprint on smaller machines.
 287
 288           ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
 289             out the irq_desc[] array in a more NUMA-friendly way. )
 290
 291           If you don't know what to do here, say N.
 292
 293 config NUMA_IRQ_DESC
 294         def_bool y
 295         depends on SPARSE_IRQ && NUMA
 296
 297 config X86_MPPARSE
 298         bool "Enable MPS table" if ACPI
 299         default y
 300         depends on X86_LOCAL_APIC
 301         ---help---
 302           For old smp systems that do not have proper acpi support. Newer systems
 303           (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
 304
 305 config X86_BIGSMP
 306         bool "Support for big SMP systems with more than 8 CPUs"
 307         depends on X86_32 && SMP
 308         ---help---
 309           This option is needed for the systems that have more than 8 CPUs
 310
 311 if X86_32
 312 config X86_EXTENDED_PLATFORM
 313         bool "Support for extended (non-PC) x86 platforms"
 314         default y
 315         ---help---
 316           If you disable this option then the kernel will only support
 317           standard PC platforms. (which covers the vast majority of
 318           systems out there.)
 319
 320           If you enable this option then you'll be able to select support
 321           for the following (non-PC) 32 bit x86 platforms:
 322                 AMD Elan
 323                 NUMAQ (IBM/Sequent)
 324                 RDC R-321x SoC
 325                 SGI 320/540 (Visual Workstation)
 326                 Summit/EXA (IBM x440)
 327                 Unisys ES7000 IA32 series
 328
 329           If you have one of these systems, or if you want to build a
 330           generic distribution kernel, say Y here - otherwise say N.
 331 endif
 332
 333 if X86_64
 334 config X86_EXTENDED_PLATFORM
 335         bool "Support for extended (non-PC) x86 platforms"
 336         default y
 337         ---help---
 338           If you disable this option then the kernel will only support
 339           standard PC platforms. (which covers the vast majority of
 340           systems out there.)
 341
 342           If you enable this option then you'll be able to select support
 343           for the following (non-PC) 64 bit x86 platforms:
 344                 ScaleMP vSMP
 345                 SGI Ultraviolet
 346
 347           If you have one of these systems, or if you want to build a
 348           generic distribution kernel, say Y here - otherwise say N.
 349 endif
 350 # This is an alphabetically sorted list of 64 bit extended platforms
 351 # Please maintain the alphabetic order if and when there are additions
 352
 353 config X86_VSMP
 354         bool "ScaleMP vSMP"
 355         select PARAVIRT
 356         depends on X86_64 && PCI
 357         depends on X86_EXTENDED_PLATFORM
 358         ---help---
 359           Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
 360           supposed to run on these EM64T-based machines.  Only choose this option
 361           if you have one of these machines.
 362
 363 config X86_UV
 364         bool "SGI Ultraviolet"
 365         depends on X86_64
 366         depends on X86_EXTENDED_PLATFORM
 367         depends on NUMA
 368         depends on X86_X2APIC
 369         ---help---
 370           This option is needed in order to support SGI Ultraviolet systems.
 371           If you don't have one of these, you should say N here.
 372
 373 # Following is an alphabetically sorted list of 32 bit extended platforms
 374 # Please maintain the alphabetic order if and when there are additions
 375
 376 config X86_ELAN
 377         bool "AMD Elan"
 378         depends on X86_32
 379         depends on X86_EXTENDED_PLATFORM
 380         ---help---
 381           Select this for an AMD Elan processor.
 382
 383           Do not use this option for K6/Athlon/Opteron processors!
 384
 385           If unsure, choose "PC-compatible" instead.
 386
 387 config X86_RDC321X
 388         bool "RDC R-321x SoC"
 389         depends on X86_32
 390         depends on X86_EXTENDED_PLATFORM
 391         select M486
 392         select X86_REBOOTFIXUPS
 393         ---help---
 394           This option is needed for RDC R-321x system-on-chip, also known
 395           as R-8610-(G).
 396           If you don't have one of these chips, you should say N here.
 397
 398 config X86_32_NON_STANDARD
 399         bool "Support non-standard 32-bit SMP architectures"
 400         depends on X86_32 && SMP
 401         depends on X86_EXTENDED_PLATFORM
 402         ---help---
 403           This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
 404           subarchitectures.  It is intended for a generic binary kernel.
 405           if you select them all, kernel will probe it one by one. and will
 406           fallback to default.
 407
 408 # Alphabetically sorted list of Non standard 32 bit platforms
 409
 410 config X86_NUMAQ
 411         bool "NUMAQ (IBM/Sequent)"
 412         depends on X86_32_NON_STANDARD
 413         select NUMA
 414         select X86_MPPARSE
 415         ---help---
 416           This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
 417           NUMA multiquad box. This changes the way that processors are
 418           bootstrapped, and uses Clustered Logical APIC addressing mode instead
 419           of Flat Logical.  You will need a new lynxer.elf file to flash your
 420           firmware with - send email to <Martin.Bligh@us.ibm.com>.
 421
 422 config X86_VISWS
 423         bool "SGI 320/540 (Visual Workstation)"
 424         depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
 425         depends on X86_32_NON_STANDARD
 426         ---help---
 427           The SGI Visual Workstation series is an IA32-based workstation
 428           based on SGI systems chips with some legacy PC hardware attached.
 429
 430           Say Y here to create a kernel to run on the SGI 320 or 540.
 431
 432           A kernel compiled for the Visual Workstation will run on general
 433           PCs as well. See <file:Documentation/sgi-visws.txt> for details.
 434
 435 config X86_SUMMIT
 436         bool "Summit/EXA (IBM x440)"
 437         depends on X86_32_NON_STANDARD
 438         ---help---
 439           This option is needed for IBM systems that use the Summit/EXA chipset.
 440           In particular, it is needed for the x440.
 441
 442 config X86_ES7000
 443         bool "Unisys ES7000 IA32 series"
 444         depends on X86_32_NON_STANDARD && X86_BIGSMP
 445         ---help---
 446           Support for Unisys ES7000 systems.  Say 'Y' here if this kernel is
 447           supposed to run on an IA32-based Unisys ES7000 system.
 448
 449 config SCHED_OMIT_FRAME_POINTER
 450         def_bool y
 451         prompt "Single-depth WCHAN output"
 452         depends on X86
 453         ---help---
 454           Calculate simpler /proc/<PID>/wchan values. If this option
 455           is disabled then wchan values will recurse back to the
 456           caller function. This provides more accurate wchan values,
 457           at the expense of slightly more scheduling overhead.
 458
 459           If in doubt, say "Y".
 460
 461 menuconfig PARAVIRT_GUEST
 462         bool "Paravirtualized guest support"
 463         ---help---
 464           Say Y here to get to see options related to running Linux under
 465           various hypervisors.  This option alone does not add any kernel code.
 466
 467           If you say N, all options in this submenu will be skipped and disabled.
 468
 469 if PARAVIRT_GUEST
 470
 471 source "arch/x86/xen/Kconfig"
 472
 473 config VMI
 474         bool "VMI Guest support"
 475         select PARAVIRT
 476         depends on X86_32
 477         ---help---
 478           VMI provides a paravirtualized interface to the VMware ESX server
 479           (it could be used by other hypervisors in theory too, but is not
 480           at the moment), by linking the kernel to a GPL-ed ROM module
 481           provided by the hypervisor.
 482
 483 config KVM_CLOCK
 484         bool "KVM paravirtualized clock"
 485         select PARAVIRT
 486         select PARAVIRT_CLOCK
 487         ---help---
 488           Turning on this option will allow you to run a paravirtualized clock
 489           when running over the KVM hypervisor. Instead of relying on a PIT
 490           (or probably other) emulation by the underlying device model, the host
 491           provides the guest with timing infrastructure such as time of day, and
 492           system time
 493
 494 config KVM_GUEST
 495         bool "KVM Guest support"
 496         select PARAVIRT
 497         ---help---
 498           This option enables various optimizations for running under the KVM
 499           hypervisor.
 500
 501 source "arch/x86/lguest/Kconfig"
 502
 503 config PARAVIRT
 504         bool "Enable paravirtualization code"
 505         ---help---
 506           This changes the kernel so it can modify itself when it is run
 507           under a hypervisor, potentially improving performance significantly
 508           over full virtualization.  However, when run without a hypervisor
 509           the kernel is theoretically slower and slightly larger.
 510
 511 config PARAVIRT_SPINLOCKS
 512         bool "Paravirtualization layer for spinlocks"
 513         depends on PARAVIRT && SMP && EXPERIMENTAL
 514         ---help---
 515           Paravirtualized spinlocks allow a pvops backend to replace the
 516           spinlock implementation with something virtualization-friendly
 517           (for example, block the virtual CPU rather than spinning).
 518
 519           Unfortunately the downside is an up to 5% performance hit on
 520           native kernels, with various workloads.
 521
 522           If you are unsure how to answer this question, answer N.
 523
 524 config PARAVIRT_CLOCK
 525         bool
 526         default n
 527
 528 endif
 529
 530 config PARAVIRT_DEBUG
 531         bool "paravirt-ops debugging"
 532         depends on PARAVIRT && DEBUG_KERNEL
 533         ---help---
 534           Enable to debug paravirt_ops internals.  Specifically, BUG if
 535           a paravirt_op is missing when it is called.
 536
 537 config MEMTEST
 538         bool "Memtest"
 539         ---help---
 540           This option adds a kernel parameter 'memtest', which allows memtest
 541           to be set.
 542                 memtest=0, mean disabled; -- default
 543                 memtest=1, mean do 1 test pattern;
 544                 ...
 545                 memtest=4, mean do 4 test patterns.
 546           If you are unsure how to answer this question, answer N.
 547
 548 config X86_SUMMIT_NUMA
 549         def_bool y
 550         depends on X86_32 && NUMA && X86_32_NON_STANDARD
 551
 552 config X86_CYCLONE_TIMER
 553         def_bool y
 554         depends on X86_32_NON_STANDARD
 555
 556 source "arch/x86/Kconfig.cpu"
 557
 558 config HPET_TIMER
 559         def_bool X86_64
 560         prompt "HPET Timer Support" if X86_32
 561         ---help---
 562           Use the IA-PC HPET (High Precision Event Timer) to manage
 563           time in preference to the PIT and RTC, if a HPET is
 564           present.
 565           HPET is the next generation timer replacing legacy 8254s.
 566           The HPET provides a stable time base on SMP
 567           systems, unlike the TSC, but it is more expensive to access,
 568           as it is off-chip.  You can find the HPET spec at
 569           <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
 570
 571           You can safely choose Y here.  However, HPET will only be
 572           activated if the platform and the BIOS support this feature.
 573           Otherwise the 8254 will be used for timing services.
 574
 575           Choose N to continue using the legacy 8254 timer.
 576
 577 config HPET_EMULATE_RTC
 578         def_bool y
 579         depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
 580
 581 # Mark as embedded because too many people got it wrong.
 582 # The code disables itself when not needed.
 583 config DMI
 584         default y
 585         bool "Enable DMI scanning" if EMBEDDED
 586         ---help---
 587           Enabled scanning of DMI to identify machine quirks. Say Y
 588           here unless you have verified that your setup is not
 589           affected by entries in the DMI blacklist. Required by PNP
 590           BIOS code.
 591
 592 config GART_IOMMU
 593         bool "GART IOMMU support" if EMBEDDED
 594         default y
 595         select SWIOTLB
 596         depends on X86_64 && PCI
 597         ---help---
 598           Support for full DMA access of devices with 32bit memory access only
 599           on systems with more than 3GB. This is usually needed for USB,
 600           sound, many IDE/SATA chipsets and some other devices.
 601           Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
 602           based hardware IOMMU and a software bounce buffer based IOMMU used
 603           on Intel systems and as fallback.
 604           The code is only active when needed (enough memory and limited
 605           device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
 606           too.
 607
 608 config CALGARY_IOMMU
 609         bool "IBM Calgary IOMMU support"
 610         select SWIOTLB
 611         depends on X86_64 && PCI && EXPERIMENTAL
 612         ---help---
 613           Support for hardware IOMMUs in IBM's xSeries x366 and x460
 614           systems. Needed to run systems with more than 3GB of memory
 615           properly with 32-bit PCI devices that do not support DAC
 616           (Double Address Cycle). Calgary also supports bus level
 617           isolation, where all DMAs pass through the IOMMU.  This
 618           prevents them from going anywhere except their intended
 619           destination. This catches hard-to-find kernel bugs and
 620           mis-behaving drivers and devices that do not use the DMA-API
 621           properly to set up their DMA buffers.  The IOMMU can be
 622           turned off at boot time with the iommu=off parameter.
 623           Normally the kernel will make the right choice by itself.
 624           If unsure, say Y.
 625
 626 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
 627         def_bool y
 628         prompt "Should Calgary be enabled by default?"
 629         depends on CALGARY_IOMMU
 630         ---help---
 631           Should Calgary be enabled by default? if you choose 'y', Calgary
 632           will be used (if it exists). If you choose 'n', Calgary will not be
 633           used even if it exists. If you choose 'n' and would like to use
 634           Calgary anyway, pass 'iommu=calgary' on the kernel command line.
 635           If unsure, say Y.
 636
 637 config AMD_IOMMU
 638         bool "AMD IOMMU support"
 639         select SWIOTLB
 640         select PCI_MSI
 641         depends on X86_64 && PCI && ACPI
 642         ---help---
 643           With this option you can enable support for AMD IOMMU hardware in
 644           your system. An IOMMU is a hardware component which provides
 645           remapping of DMA memory accesses from devices. With an AMD IOMMU you
 646           can isolate the the DMA memory of different devices and protect the
 647           system from misbehaving device drivers or hardware.
 648
 649           You can find out if your system has an AMD IOMMU if you look into
 650           your BIOS for an option to enable it or if you have an IVRS ACPI
 651           table.
 652
 653 config AMD_IOMMU_STATS
 654         bool "Export AMD IOMMU statistics to debugfs"
 655         depends on AMD_IOMMU
 656         select DEBUG_FS
 657         ---help---
 658           This option enables code in the AMD IOMMU driver to collect various
 659           statistics about whats happening in the driver and exports that
 660           information to userspace via debugfs.
 661           If unsure, say N.
 662
 663 # need this always selected by IOMMU for the VIA workaround
 664 config SWIOTLB
 665         def_bool y if X86_64
 666         ---help---
 667           Support for software bounce buffers used on x86-64 systems
 668           which don't have a hardware IOMMU (e.g. the current generation
 669           of Intel's x86-64 CPUs). Using this PCI devices which can only
 670           access 32-bits of memory can be used on systems with more than
 671           3 GB of memory. If unsure, say Y.
 672
 673 config IOMMU_HELPER
 674         def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
 675
 676 config IOMMU_API
 677         def_bool (AMD_IOMMU || DMAR)
 678
 679 config MAXSMP
 680         bool "Configure Maximum number of SMP Processors and NUMA Nodes"
 681         depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
 682         select CPUMASK_OFFSTACK
 683         default n
 684         ---help---
 685           Configure maximum number of CPUS and NUMA Nodes for this architecture.
 686           If unsure, say N.
 687
 688 config NR_CPUS
 689         int "Maximum number of CPUs" if SMP && !MAXSMP
 690         range 2 8 if SMP && X86_32 && !X86_BIGSMP
 691         range 2 512 if SMP && !MAXSMP
 692         default "1" if !SMP
 693         default "4096" if MAXSMP
 694         default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
 695         default "8" if SMP
 696         ---help---
 697           This allows you to specify the maximum number of CPUs which this
 698           kernel will support.  The maximum supported value is 512 and the
 699           minimum value which makes sense is 2.
 700
 701           This is purely to save memory - each supported CPU adds
 702           approximately eight kilobytes to the kernel image.
 703
 704 config SCHED_SMT
 705         bool "SMT (Hyperthreading) scheduler support"
 706         depends on X86_HT
 707         ---help---
 708           SMT scheduler support improves the CPU scheduler's decision making
 709           when dealing with Intel Pentium 4 chips with HyperThreading at a
 710           cost of slightly increased overhead in some places. If unsure say
 711           N here.
 712
 713 config SCHED_MC
 714         def_bool y
 715         prompt "Multi-core scheduler support"
 716         depends on X86_HT
 717         ---help---
 718           Multi-core scheduler support improves the CPU scheduler's decision
 719           making when dealing with multi-core CPU chips at a cost of slightly
 720           increased overhead in some places. If unsure say N here.
 721
 722 source "kernel/Kconfig.preempt"
 723
 724 config X86_UP_APIC
 725         bool "Local APIC support on uniprocessors"
 726         depends on X86_32 && !SMP && !X86_32_NON_STANDARD
 727         ---help---
 728           A local APIC (Advanced Programmable Interrupt Controller) is an
 729           integrated interrupt controller in the CPU. If you have a single-CPU
 730           system which has a processor with a local APIC, you can say Y here to
 731           enable and use it. If you say Y here even though your machine doesn't
 732           have a local APIC, then the kernel will still run with no slowdown at
 733           all. The local APIC supports CPU-generated self-interrupts (timer,
 734           performance counters), and the NMI watchdog which detects hard
 735           lockups.
 736
 737 config X86_UP_IOAPIC
 738         bool "IO-APIC support on uniprocessors"
 739         depends on X86_UP_APIC
 740         ---help---
 741           An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
 742           SMP-capable replacement for PC-style interrupt controllers. Most
 743           SMP systems and many recent uniprocessor systems have one.
 744
 745           If you have a single-CPU system with an IO-APIC, you can say Y here
 746           to use it. If you say Y here even though your machine doesn't have
 747           an IO-APIC, then the kernel will still run with no slowdown at all.
 748
 749 config X86_LOCAL_APIC
 750         def_bool y
 751         depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
 752
 753 config X86_IO_APIC
 754         def_bool y
 755         depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
 756
 757 config X86_VISWS_APIC
 758         def_bool y
 759         depends on X86_32 && X86_VISWS
 760
 761 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
 762         bool "Reroute for broken boot IRQs"
 763         default n
 764         depends on X86_IO_APIC
 765         ---help---
 766           This option enables a workaround that fixes a source of
 767           spurious interrupts. This is recommended when threaded
 768           interrupt handling is used on systems where the generation of
 769           superfluous "boot interrupts" cannot be disabled.
 770
 771           Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
 772           entry in the chipset's IO-APIC is masked (as, e.g. the RT
 773           kernel does during interrupt handling). On chipsets where this
 774           boot IRQ generation cannot be disabled, this workaround keeps
 775           the original IRQ line masked so that only the equivalent "boot
 776           IRQ" is delivered to the CPUs. The workaround also tells the
 777           kernel to set up the IRQ handler on the boot IRQ line. In this
 778           way only one interrupt is delivered to the kernel. Otherwise
 779           the spurious second interrupt may cause the kernel to bring
 780           down (vital) interrupt lines.
 781
 782           Only affects "broken" chipsets. Interrupt sharing may be
 783           increased on these systems.
 784
 785 config X86_MCE
 786         bool "Machine Check / overheating reporting"
 787         ---help---
 788           Machine Check support allows the processor to notify the
 789           kernel if it detects a problem (e.g. overheating, data corruption).
 790           The action the kernel takes depends on the severity of the problem,
 791           ranging from warning messages to halting the machine.
 792
 793 config X86_MCE_INTEL
 794         def_bool y
 795         prompt "Intel MCE features"
 796         depends on X86_MCE && X86_LOCAL_APIC
 797         ---help---
 798            Additional support for intel specific MCE features such as
 799            the thermal monitor.
 800
 801 config X86_MCE_AMD
 802         def_bool y
 803         prompt "AMD MCE features"
 804         depends on X86_MCE && X86_LOCAL_APIC
 805         ---help---
 806            Additional support for AMD specific MCE features such as
 807            the DRAM Error Threshold.
 808
 809 config X86_ANCIENT_MCE
 810         def_bool n
 811         depends on X86_32 && X86_MCE
 812         prompt "Support for old Pentium 5 / WinChip machine checks"
 813         ---help---
 814           Include support for machine check handling on old Pentium 5 or WinChip
 815           systems. These typically need to be enabled explicitely on the command
 816           line.
 817
 818 config X86_MCE_THRESHOLD
 819         depends on X86_MCE_AMD || X86_MCE_INTEL
 820         bool
 821         default y
 822
 823 config X86_MCE_INJECT
 824         depends on X86_MCE
 825         tristate "Machine check injector support"
 826         ---help---
 827           Provide support for injecting machine checks for testing purposes.
 828           If you don't know what a machine check is and you don't do kernel
 829           QA it is safe to say n.
 830
 831 config X86_THERMAL_VECTOR
 832         def_bool y
 833         depends on X86_MCE_INTEL
 834
 835 config VM86
 836         bool "Enable VM86 support" if EMBEDDED
 837         default y
 838         depends on X86_32
 839         ---help---
 840           This option is required by programs like DOSEMU to run 16-bit legacy
 841           code on X86 processors. It also may be needed by software like
 842           XFree86 to initialize some video cards via BIOS. Disabling this
 843           option saves about 6k.
 844
 845 config TOSHIBA
 846         tristate "Toshiba Laptop support"
 847         depends on X86_32
 848         ---help---
 849           This adds a driver to safely access the System Management Mode of
 850           the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
 851           not work on models with a Phoenix BIOS. The System Management Mode
 852           is used to set the BIOS and power saving options on Toshiba portables.
 853
 854           For information on utilities to make use of this driver see the
 855           Toshiba Linux utilities web site at:
 856           <http://www.buzzard.org.uk/toshiba/>.
 857
 858           Say Y if you intend to run this kernel on a Toshiba portable.
 859           Say N otherwise.
 860
 861 config I8K
 862         tristate "Dell laptop support"
 863         ---help---
 864           This adds a driver to safely access the System Management Mode
 865           of the CPU on the Dell Inspiron 8000. The System Management Mode
 866           is used to read cpu temperature and cooling fan status and to
 867           control the fans on the I8K portables.
 868
 869           This driver has been tested only on the Inspiron 8000 but it may
 870           also work with other Dell laptops. You can force loading on other
 871           models by passing the parameter `force=1' to the module. Use at
 872           your own risk.
 873
 874           For information on utilities to make use of this driver see the
 875           I8K Linux utilities web site at:
 876           <http://people.debian.org/~dz/i8k/>
 877
 878           Say Y if you intend to run this kernel on a Dell Inspiron 8000.
 879           Say N otherwise.
 880
 881 config X86_REBOOTFIXUPS
 882         bool "Enable X86 board specific fixups for reboot"
 883         depends on X86_32
 884         ---help---
 885           This enables chipset and/or board specific fixups to be done
 886           in order to get reboot to work correctly. This is only needed on
 887           some combinations of hardware and BIOS. The symptom, for which
 888           this config is intended, is when reboot ends with a stalled/hung
 889           system.
 890
 891           Currently, the only fixup is for the Geode machines using
 892           CS5530A and CS5536 chipsets and the RDC R-321x SoC.
 893
 894           Say Y if you want to enable the fixup. Currently, it's safe to
 895           enable this option even if you don't need it.
 896           Say N otherwise.
 897
 898 config MICROCODE
 899         tristate "/dev/cpu/microcode - microcode support"
 900         select FW_LOADER
 901         ---help---
 902           If you say Y here, you will be able to update the microcode on
 903           certain Intel and AMD processors. The Intel support is for the
 904           IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
 905           Pentium 4, Xeon etc. The AMD support is for family 0x10 and
 906           0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
 907           You will obviously need the actual microcode binary data itself
 908           which is not shipped with the Linux kernel.
 909
 910           This option selects the general module only, you need to select
 911           at least one vendor specific module as well.
 912
 913           To compile this driver as a module, choose M here: the
 914           module will be called microcode.
 915
 916 config MICROCODE_INTEL
 917         bool "Intel microcode patch loading support"
 918         depends on MICROCODE
 919         default MICROCODE
 920         select FW_LOADER
 921         ---help---
 922           This options enables microcode patch loading support for Intel
 923           processors.
 924
 925           For latest news and information on obtaining all the required
 926           Intel ingredients for this driver, check:
 927           <http://www.urbanmyth.org/microcode/>.
 928
 929 config MICROCODE_AMD
 930         bool "AMD microcode patch loading support"
 931         depends on MICROCODE
 932         select FW_LOADER
 933         ---help---
 934           If you select this option, microcode patch loading support for AMD
 935           processors will be enabled.
 936
 937 config MICROCODE_OLD_INTERFACE
 938         def_bool y
 939         depends on MICROCODE
 940
 941 config X86_MSR
 942         tristate "/dev/cpu/*/msr - Model-specific register support"
 943         ---help---
 944           This device gives privileged processes access to the x86
 945           Model-Specific Registers (MSRs).  It is a character device with
 946           major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
 947           MSR accesses are directed to a specific CPU on multi-processor
 948           systems.
 949
 950 config X86_CPUID
 951         tristate "/dev/cpu/*/cpuid - CPU information support"
 952         ---help---
 953           This device gives processes access to the x86 CPUID instruction to
 954           be executed on a specific processor.  It is a character device
 955           with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
 956           /dev/cpu/31/cpuid.
 957
 958 config X86_CPU_DEBUG
 959         tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
 960         ---help---
 961           If you select this option, this will provide various x86 CPUs
 962           information through debugfs.
 963
 964 choice
 965         prompt "High Memory Support"
 966         default HIGHMEM4G if !X86_NUMAQ
 967         default HIGHMEM64G if X86_NUMAQ
 968         depends on X86_32
 969
 970 config NOHIGHMEM
 971         bool "off"
 972         depends on !X86_NUMAQ
 973         ---help---
 974           Linux can use up to 64 Gigabytes of physical memory on x86 systems.
 975           However, the address space of 32-bit x86 processors is only 4
 976           Gigabytes large. That means that, if you have a large amount of
 977           physical memory, not all of it can be "permanently mapped" by the
 978           kernel. The physical memory that's not permanently mapped is called
 979           "high memory".
 980
 981           If you are compiling a kernel which will never run on a machine with
 982           more than 1 Gigabyte total physical RAM, answer "off" here (default
 983           choice and suitable for most users). This will result in a "3GB/1GB"
 984           split: 3GB are mapped so that each process sees a 3GB virtual memory
 985           space and the remaining part of the 4GB virtual memory space is used
 986           by the kernel to permanently map as much physical memory as
 987           possible.
 988
 989           If the machine has between 1 and 4 Gigabytes physical RAM, then
 990           answer "4GB" here.
 991
 992           If more than 4 Gigabytes is used then answer "64GB" here. This
 993           selection turns Intel PAE (Physical Address Extension) mode on.
 994           PAE implements 3-level paging on IA32 processors. PAE is fully
 995           supported by Linux, PAE mode is implemented on all recent Intel
 996           processors (Pentium Pro and better). NOTE: If you say "64GB" here,
 997           then the kernel will not boot on CPUs that don't support PAE!
 998
 999           The actual amount of total physical memory will either be
1000           auto detected or can be forced by using a kernel command line option
1001           such as "mem=256M". (Try "man bootparam" or see the documentation of
1002           your boot loader (lilo or loadlin) about how to pass options to the
1003           kernel at boot time.)
1004
1005           If unsure, say "off".
1006
1007 config HIGHMEM4G
1008         bool "4GB"
1009         depends on !X86_NUMAQ
1010         ---help---
1011           Select this if you have a 32-bit processor and between 1 and 4
1012           gigabytes of physical RAM.
1013
1014 config HIGHMEM64G
1015         bool "64GB"
1016         depends on !M386 && !M486
1017         select X86_PAE
1018         ---help---
1019           Select this if you have a 32-bit processor and more than 4
1020           gigabytes of physical RAM.
1021
1022 endchoice
1023
1024 choice
1025         depends on EXPERIMENTAL
1026         prompt "Memory split" if EMBEDDED
1027         default VMSPLIT_3G
1028         depends on X86_32
1029         ---help---
1030           Select the desired split between kernel and user memory.
1031
1032           If the address range available to the kernel is less than the
1033           physical memory installed, the remaining memory will be available
1034           as "high memory". Accessing high memory is a little more costly
1035           than low memory, as it needs to be mapped into the kernel first.
1036           Note that increasing the kernel address space limits the range
1037           available to user programs, making the address space there
1038           tighter.  Selecting anything other than the default 3G/1G split
1039           will also likely make your kernel incompatible with binary-only
1040           kernel modules.
1041
1042           If you are not absolutely sure what you are doing, leave this
1043           option alone!
1044
1045         config VMSPLIT_3G
1046                 bool "3G/1G user/kernel split"
1047         config VMSPLIT_3G_OPT
1048                 depends on !X86_PAE
1049                 bool "3G/1G user/kernel split (for full 1G low memory)"
1050         config VMSPLIT_2G
1051                 bool "2G/2G user/kernel split"
1052         config VMSPLIT_2G_OPT
1053                 depends on !X86_PAE
1054                 bool "2G/2G user/kernel split (for full 2G low memory)"
1055         config VMSPLIT_1G
1056                 bool "1G/3G user/kernel split"
1057 endchoice
1058
1059 config PAGE_OFFSET
1060         hex
1061         default 0xB0000000 if VMSPLIT_3G_OPT
1062         default 0x80000000 if VMSPLIT_2G
1063         default 0x78000000 if VMSPLIT_2G_OPT
1064         default 0x40000000 if VMSPLIT_1G
1065         default 0xC0000000
1066         depends on X86_32
1067
1068 config HIGHMEM
1069         def_bool y
1070         depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1071
1072 config X86_PAE
1073         bool "PAE (Physical Address Extension) Support"
1074         depends on X86_32 && !HIGHMEM4G
1075         ---help---
1076           PAE is required for NX support, and furthermore enables
1077           larger swapspace support for non-overcommit purposes. It
1078           has the cost of more pagetable lookup overhead, and also
1079           consumes more pagetable space per process.
1080
1081 config ARCH_PHYS_ADDR_T_64BIT
1082         def_bool X86_64 || X86_PAE
1083
1084 config DIRECT_GBPAGES
1085         bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1086         default y
1087         depends on X86_64
1088         ---help---
1089           Allow the kernel linear mapping to use 1GB pages on CPUs that
1090           support it. This can improve the kernel's performance a tiny bit by
1091           reducing TLB pressure. If in doubt, say "Y".
1092
1093 # Common NUMA Features
1094 config NUMA
1095         bool "Numa Memory Allocation and Scheduler Support"
1096         depends on SMP
1097         depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1098         default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1099         ---help---
1100           Enable NUMA (Non Uniform Memory Access) support.
1101
1102           The kernel will try to allocate memory used by a CPU on the
1103           local memory controller of the CPU and add some more
1104           NUMA awareness to the kernel.
1105
1106           For 64-bit this is recommended if the system is Intel Core i7
1107           (or later), AMD Opteron, or EM64T NUMA.
1108
1109           For 32-bit this is only needed on (rare) 32-bit-only platforms
1110           that support NUMA topologies, such as NUMAQ / Summit, or if you
1111           boot a 32-bit kernel on a 64-bit NUMA platform.
1112
1113           Otherwise, you should say N.
1114
1115 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1116         depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1117
1118 config K8_NUMA
1119         def_bool y
1120         prompt "Old style AMD Opteron NUMA detection"
1121         depends on X86_64 && NUMA && PCI
1122         ---help---
1123           Enable K8 NUMA node topology detection.  You should say Y here if
1124           you have a multi processor AMD K8 system. This uses an old
1125           method to read the NUMA configuration directly from the builtin
1126           Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1127           instead, which also takes priority if both are compiled in.
1128
1129 config X86_64_ACPI_NUMA
1130         def_bool y
1131         prompt "ACPI NUMA detection"
1132         depends on X86_64 && NUMA && ACPI && PCI
1133         select ACPI_NUMA
1134         ---help---
1135           Enable ACPI SRAT based node topology detection.
1136
1137 # Some NUMA nodes have memory ranges that span
1138 # other nodes.  Even though a pfn is valid and
1139 # between a node's start and end pfns, it may not
1140 # reside on that node.  See memmap_init_zone()
1141 # for details.
1142 config NODES_SPAN_OTHER_NODES
1143         def_bool y
1144         depends on X86_64_ACPI_NUMA
1145
1146 config NUMA_EMU
1147         bool "NUMA emulation"
1148         depends on X86_64 && NUMA
1149         ---help---
1150           Enable NUMA emulation. A flat machine will be split
1151           into virtual nodes when booted with "numa=fake=N", where N is the
1152           number of nodes. This is only useful for debugging.
1153
1154 config NODES_SHIFT
1155         int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1156         range 1 9
1157         default "9" if MAXSMP
1158         default "6" if X86_64
1159         default "4" if X86_NUMAQ
1160         default "3"
1161         depends on NEED_MULTIPLE_NODES
1162         ---help---
1163           Specify the maximum number of NUMA Nodes available on the target
1164           system.  Increases memory reserved to accommodate various tables.
1165
1166 config HAVE_ARCH_BOOTMEM
1167         def_bool y
1168         depends on X86_32 && NUMA
1169
1170 config ARCH_HAVE_MEMORY_PRESENT
1171         def_bool y
1172         depends on X86_32 && DISCONTIGMEM
1173
1174 config NEED_NODE_MEMMAP_SIZE
1175         def_bool y
1176         depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1177
1178 config HAVE_ARCH_ALLOC_REMAP
1179         def_bool y
1180         depends on X86_32 && NUMA
1181
1182 config ARCH_FLATMEM_ENABLE
1183         def_bool y
1184         depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1185
1186 config ARCH_DISCONTIGMEM_ENABLE
1187         def_bool y
1188         depends on NUMA && X86_32
1189
1190 config ARCH_DISCONTIGMEM_DEFAULT
1191         def_bool y
1192         depends on NUMA && X86_32
1193
1194 config ARCH_SPARSEMEM_DEFAULT
1195         def_bool y
1196         depends on X86_64
1197
1198 config ARCH_SPARSEMEM_ENABLE
1199         def_bool y
1200         depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1201         select SPARSEMEM_STATIC if X86_32
1202         select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1203
1204 config ARCH_SELECT_MEMORY_MODEL
1205         def_bool y
1206         depends on ARCH_SPARSEMEM_ENABLE
1207
1208 config ARCH_MEMORY_PROBE
1209         def_bool X86_64
1210         depends on MEMORY_HOTPLUG
1211
1212 source "mm/Kconfig"
1213
1214 config HIGHPTE
1215         bool "Allocate 3rd-level pagetables from highmem"
1216         depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1217         ---help---
1218           The VM uses one page table entry for each page of physical memory.
1219           For systems with a lot of RAM, this can be wasteful of precious
1220           low memory.  Setting this option will put user-space page table
1221           entries in high memory.
1222
1223 config X86_CHECK_BIOS_CORRUPTION
1224         bool "Check for low memory corruption"
1225         ---help---
1226           Periodically check for memory corruption in low memory, which
1227           is suspected to be caused by BIOS.  Even when enabled in the
1228           configuration, it is disabled at runtime.  Enable it by
1229           setting "memory_corruption_check=1" on the kernel command
1230           line.  By default it scans the low 64k of memory every 60
1231           seconds; see the memory_corruption_check_size and
1232           memory_corruption_check_period parameters in
1233           Documentation/kernel-parameters.txt to adjust this.
1234
1235           When enabled with the default parameters, this option has
1236           almost no overhead, as it reserves a relatively small amount
1237           of memory and scans it infrequently.  It both detects corruption
1238           and prevents it from affecting the running system.
1239
1240           It is, however, intended as a diagnostic tool; if repeatable
1241           BIOS-originated corruption always affects the same memory,
1242           you can use memmap= to prevent the kernel from using that
1243           memory.
1244
1245 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1246         bool "Set the default setting of memory_corruption_check"
1247         depends on X86_CHECK_BIOS_CORRUPTION
1248         default y
1249         ---help---
1250           Set whether the default state of memory_corruption_check is
1251           on or off.
1252
1253 config X86_RESERVE_LOW_64K
1254         bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1255         default y
1256         ---help---
1257           Reserve the first 64K of physical RAM on BIOSes that are known
1258           to potentially corrupt that memory range. A numbers of BIOSes are
1259           known to utilize this area during suspend/resume, so it must not
1260           be used by the kernel.
1261
1262           Set this to N if you are absolutely sure that you trust the BIOS
1263           to get all its memory reservations and usages right.
1264
1265           If you have doubts about the BIOS (e.g. suspend/resume does not
1266           work or there's kernel crashes after certain hardware hotplug
1267           events) and it's not AMI or Phoenix, then you might want to enable
1268           X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1269           corruption patterns.
1270
1271           Say Y if unsure.
1272
1273 config MATH_EMULATION
1274         bool
1275         prompt "Math emulation" if X86_32
1276         ---help---
1277           Linux can emulate a math coprocessor (used for floating point
1278           operations) if you don't have one. 486DX and Pentium processors have
1279           a math coprocessor built in, 486SX and 386 do not, unless you added
1280           a 487DX or 387, respectively. (The messages during boot time can
1281           give you some hints here ["man dmesg"].) Everyone needs either a
1282           coprocessor or this emulation.
1283
1284           If you don't have a math coprocessor, you need to say Y here; if you
1285           say Y here even though you have a coprocessor, the coprocessor will
1286           be used nevertheless. (This behavior can be changed with the kernel
1287           command line option "no387", which comes handy if your coprocessor
1288           is broken. Try "man bootparam" or see the documentation of your boot
1289           loader (lilo or loadlin) about how to pass options to the kernel at
1290           boot time.) This means that it is a good idea to say Y here if you
1291           intend to use this kernel on different machines.
1292
1293           More information about the internals of the Linux math coprocessor
1294           emulation can be found in <file:arch/x86/math-emu/README>.
1295
1296           If you are not sure, say Y; apart from resulting in a 66 KB bigger
1297           kernel, it won't hurt.
1298
1299 config MTRR
1300         bool "MTRR (Memory Type Range Register) support"
1301         ---help---
1302           On Intel P6 family processors (Pentium Pro, Pentium II and later)
1303           the Memory Type Range Registers (MTRRs) may be used to control
1304           processor access to memory ranges. This is most useful if you have
1305           a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1306           allows bus write transfers to be combined into a larger transfer
1307           before bursting over the PCI/AGP bus. This can increase performance
1308           of image write operations 2.5 times or more. Saying Y here creates a
1309           /proc/mtrr file which may be used to manipulate your processor's
1310           MTRRs. Typically the X server should use this.
1311
1312           This code has a reasonably generic interface so that similar
1313           control registers on other processors can be easily supported
1314           as well:
1315
1316           The Cyrix 6x86, 6x86MX and M II processors have Address Range
1317           Registers (ARRs) which provide a similar functionality to MTRRs. For
1318           these, the ARRs are used to emulate the MTRRs.
1319           The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1320           MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1321           write-combining. All of these processors are supported by this code
1322           and it makes sense to say Y here if you have one of them.
1323
1324           Saying Y here also fixes a problem with buggy SMP BIOSes which only
1325           set the MTRRs for the boot CPU and not for the secondary CPUs. This
1326           can lead to all sorts of problems, so it's good to say Y here.
1327
1328           You can safely say Y even if your machine doesn't have MTRRs, you'll
1329           just add about 9 KB to your kernel.
1330
1331           See <file:Documentation/x86/mtrr.txt> for more information.
1332
1333 config MTRR_SANITIZER
1334         def_bool y
1335         prompt "MTRR cleanup support"
1336         depends on MTRR
1337         ---help---
1338           Convert MTRR layout from continuous to discrete, so X drivers can
1339           add writeback entries.
1340
1341           Can be disabled with disable_mtrr_cleanup on the kernel command line.
1342           The largest mtrr entry size for a continuous block can be set with
1343           mtrr_chunk_size.
1344
1345           If unsure, say Y.
1346
1347 config MTRR_SANITIZER_ENABLE_DEFAULT
1348         int "MTRR cleanup enable value (0-1)"
1349         range 0 1
1350         default "0"
1351         depends on MTRR_SANITIZER
1352         ---help---
1353           Enable mtrr cleanup default value
1354
1355 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1356         int "MTRR cleanup spare reg num (0-7)"
1357         range 0 7
1358         default "1"
1359         depends on MTRR_SANITIZER
1360         ---help---
1361           mtrr cleanup spare entries default, it can be changed via
1362           mtrr_spare_reg_nr=N on the kernel command line.
1363
1364 config X86_PAT
1365         bool
1366         prompt "x86 PAT support"
1367         depends on MTRR
1368         ---help---
1369           Use PAT attributes to setup page level cache control.
1370
1371           PATs are the modern equivalents of MTRRs and are much more
1372           flexible than MTRRs.
1373
1374           Say N here if you see bootup problems (boot crash, boot hang,
1375           spontaneous reboots) or a non-working video driver.
1376
1377           If unsure, say Y.
1378
1379 config ARCH_USES_PG_UNCACHED
1380         def_bool y
1381         depends on X86_PAT
1382
1383 config EFI
1384         bool "EFI runtime service support"
1385         depends on ACPI
1386         ---help---
1387           This enables the kernel to use EFI runtime services that are
1388           available (such as the EFI variable services).
1389
1390           This option is only useful on systems that have EFI firmware.
1391           In addition, you should use the latest ELILO loader available
1392           at <http://elilo.sourceforge.net> in order to take advantage
1393           of EFI runtime services. However, even with this option, the
1394           resultant kernel should continue to boot on existing non-EFI
1395           platforms.
1396
1397 config SECCOMP
1398         def_bool y
1399         prompt "Enable seccomp to safely compute untrusted bytecode"
1400         ---help---
1401           This kernel feature is useful for number crunching applications
1402           that may need to compute untrusted bytecode during their
1403           execution. By using pipes or other transports made available to
1404           the process as file descriptors supporting the read/write
1405           syscalls, it's possible to isolate those applications in
1406           their own address space using seccomp. Once seccomp is
1407           enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1408           and the task is only allowed to execute a few safe syscalls
1409           defined by each seccomp mode.
1410
1411           If unsure, say Y. Only embedded should say N here.
1412
1413 config CC_STACKPROTECTOR_ALL
1414         bool
1415
1416 config CC_STACKPROTECTOR
1417         bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1418         select CC_STACKPROTECTOR_ALL
1419         ---help---
1420           This option turns on the -fstack-protector GCC feature. This
1421           feature puts, at the beginning of functions, a canary value on
1422           the stack just before the return address, and validates
1423           the value just before actually returning.  Stack based buffer
1424           overflows (that need to overwrite this return address) now also
1425           overwrite the canary, which gets detected and the attack is then
1426           neutralized via a kernel panic.
1427
1428           This feature requires gcc version 4.2 or above, or a distribution
1429           gcc with the feature backported. Older versions are automatically
1430           detected and for those versions, this configuration option is
1431           ignored. (and a warning is printed during bootup)
1432
1433 source kernel/Kconfig.hz
1434
1435 config KEXEC
1436         bool "kexec system call"
1437         ---help---
1438           kexec is a system call that implements the ability to shutdown your
1439           current kernel, and to start another kernel.  It is like a reboot
1440           but it is independent of the system firmware.   And like a reboot
1441           you can start any kernel with it, not just Linux.
1442
1443           The name comes from the similarity to the exec system call.
1444
1445           It is an ongoing process to be certain the hardware in a machine
1446           is properly shutdown, so do not be surprised if this code does not
1447           initially work for you.  It may help to enable device hotplugging
1448           support.  As of this writing the exact hardware interface is
1449           strongly in flux, so no good recommendation can be made.
1450
1451 config CRASH_DUMP
1452         bool "kernel crash dumps"
1453         depends on X86_64 || (X86_32 && HIGHMEM)
1454         ---help---
1455           Generate crash dump after being started by kexec.
1456           This should be normally only set in special crash dump kernels
1457           which are loaded in the main kernel with kexec-tools into
1458           a specially reserved region and then later executed after
1459           a crash by kdump/kexec. The crash dump kernel must be compiled
1460           to a memory address not used by the main kernel or BIOS using
1461           PHYSICAL_START, or it must be built as a relocatable image
1462           (CONFIG_RELOCATABLE=y).
1463           For more details see Documentation/kdump/kdump.txt
1464
1465 config KEXEC_JUMP
1466         bool "kexec jump (EXPERIMENTAL)"
1467         depends on EXPERIMENTAL
1468         depends on KEXEC && HIBERNATION
1469         ---help---
1470           Jump between original kernel and kexeced kernel and invoke
1471           code in physical address mode via KEXEC
1472
1473 config PHYSICAL_START
1474         hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1475         default "0x1000000"
1476         ---help---
1477           This gives the physical address where the kernel is loaded.
1478
1479           If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1480           bzImage will decompress itself to above physical address and
1481           run from there. Otherwise, bzImage will run from the address where
1482           it has been loaded by the boot loader and will ignore above physical
1483           address.
1484
1485           In normal kdump cases one does not have to set/change this option
1486           as now bzImage can be compiled as a completely relocatable image
1487           (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1488           address. This option is mainly useful for the folks who don't want
1489           to use a bzImage for capturing the crash dump and want to use a
1490           vmlinux instead. vmlinux is not relocatable hence a kernel needs
1491           to be specifically compiled to run from a specific memory area
1492           (normally a reserved region) and this option comes handy.
1493
1494           So if you are using bzImage for capturing the crash dump,
1495           leave the value here unchanged to 0x1000000 and set
1496           CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
1497           for capturing the crash dump change this value to start of
1498           the reserved region.  In other words, it can be set based on
1499           the "X" value as specified in the "crashkernel=YM@XM"
1500           command line boot parameter passed to the panic-ed
1501           kernel. Please take a look at Documentation/kdump/kdump.txt
1502           for more details about crash dumps.
1503
1504           Usage of bzImage for capturing the crash dump is recommended as
1505           one does not have to build two kernels. Same kernel can be used
1506           as production kernel and capture kernel. Above option should have
1507           gone away after relocatable bzImage support is introduced. But it
1508           is present because there are users out there who continue to use
1509           vmlinux for dump capture. This option should go away down the
1510           line.
1511
1512           Don't change this unless you know what you are doing.
1513
1514 config RELOCATABLE
1515         bool "Build a relocatable kernel"
1516         default y
1517         ---help---
1518           This builds a kernel image that retains relocation information
1519           so it can be loaded someplace besides the default 1MB.
1520           The relocations tend to make the kernel binary about 10% larger,
1521           but are discarded at runtime.
1522
1523           One use is for the kexec on panic case where the recovery kernel
1524           must live at a different physical address than the primary
1525           kernel.
1526
1527           Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1528           it has been loaded at and the compile time physical address
1529           (CONFIG_PHYSICAL_START) is ignored.
1530
1531 # Relocation on x86-32 needs some additional build support
1532 config X86_NEED_RELOCS
1533         def_bool y
1534         depends on X86_32 && RELOCATABLE
1535
1536 config PHYSICAL_ALIGN
1537         hex
1538         prompt "Alignment value to which kernel should be aligned" if X86_32
1539         default "0x1000000"
1540         range 0x2000 0x1000000
1541         ---help---
1542           This value puts the alignment restrictions on physical address
1543           where kernel is loaded and run from. Kernel is compiled for an
1544           address which meets above alignment restriction.
1545
1546           If bootloader loads the kernel at a non-aligned address and
1547           CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1548           address aligned to above value and run from there.
1549
1550           If bootloader loads the kernel at a non-aligned address and
1551           CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1552           load address and decompress itself to the address it has been
1553           compiled for and run from there. The address for which kernel is
1554           compiled already meets above alignment restrictions. Hence the
1555           end result is that kernel runs from a physical address meeting
1556           above alignment restrictions.
1557
1558           Don't change this unless you know what you are doing.
1559
1560 config HOTPLUG_CPU
1561         bool "Support for hot-pluggable CPUs"
1562         depends on SMP && HOTPLUG
1563         ---help---
1564           Say Y here to allow turning CPUs off and on. CPUs can be
1565           controlled through /sys/devices/system/cpu.
1566           ( Note: power management support will enable this option
1567             automatically on SMP systems. )
1568           Say N if you want to disable CPU hotplug.
1569
1570 config COMPAT_VDSO
1571         def_bool y
1572         prompt "Compat VDSO support"
1573         depends on X86_32 || IA32_EMULATION
1574         ---help---
1575           Map the 32-bit VDSO to the predictable old-style address too.
1576         ---help---
1577           Say N here if you are running a sufficiently recent glibc
1578           version (2.3.3 or later), to remove the high-mapped
1579           VDSO mapping and to exclusively use the randomized VDSO.
1580
1581           If unsure, say Y.
1582
1583 config CMDLINE_BOOL
1584         bool "Built-in kernel command line"
1585         default n
1586         ---help---
1587           Allow for specifying boot arguments to the kernel at
1588           build time.  On some systems (e.g. embedded ones), it is
1589           necessary or convenient to provide some or all of the
1590           kernel boot arguments with the kernel itself (that is,
1591           to not rely on the boot loader to provide them.)
1592
1593           To compile command line arguments into the kernel,
1594           set this option to 'Y', then fill in the
1595           the boot arguments in CONFIG_CMDLINE.
1596
1597           Systems with fully functional boot loaders (i.e. non-embedded)
1598           should leave this option set to 'N'.
1599
1600 config CMDLINE
1601         string "Built-in kernel command string"
1602         depends on CMDLINE_BOOL
1603         default ""
1604         ---help---
1605           Enter arguments here that should be compiled into the kernel
1606           image and used at boot time.  If the boot loader provides a
1607           command line at boot time, it is appended to this string to
1608           form the full kernel command line, when the system boots.
1609
1610           However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1611           change this behavior.
1612
1613           In most cases, the command line (whether built-in or provided
1614           by the boot loader) should specify the device for the root
1615           file system.
1616
1617 config CMDLINE_OVERRIDE
1618         bool "Built-in command line overrides boot loader arguments"
1619         default n
1620         depends on CMDLINE_BOOL
1621         ---help---
1622           Set this option to 'Y' to have the kernel ignore the boot loader
1623           command line, and use ONLY the built-in command line.
1624
1625           This is used to work around broken boot loaders.  This should
1626           be set to 'N' under normal conditions.
1627
1628 endmenu
1629
1630 config ARCH_ENABLE_MEMORY_HOTPLUG
1631         def_bool y
1632         depends on X86_64 || (X86_32 && HIGHMEM)
1633
1634 config ARCH_ENABLE_MEMORY_HOTREMOVE
1635         def_bool y
1636         depends on MEMORY_HOTPLUG
1637
1638 config HAVE_ARCH_EARLY_PFN_TO_NID
1639         def_bool X86_64
1640         depends on NUMA
1641
1642 menu "Power management and ACPI options"
1643
1644 config ARCH_HIBERNATION_HEADER
1645         def_bool y
1646         depends on X86_64 && HIBERNATION
1647
1648 source "kernel/power/Kconfig"
1649
1650 source "drivers/acpi/Kconfig"
1651
1652 config X86_APM_BOOT
1653         bool
1654         default y
1655         depends on APM || APM_MODULE
1656
1657 menuconfig APM
1658         tristate "APM (Advanced Power Management) BIOS support"
1659         depends on X86_32 && PM_SLEEP
1660         ---help---
1661           APM is a BIOS specification for saving power using several different
1662           techniques. This is mostly useful for battery powered laptops with
1663           APM compliant BIOSes. If you say Y here, the system time will be
1664           reset after a RESUME operation, the /proc/apm device will provide
1665           battery status information, and user-space programs will receive
1666           notification of APM "events" (e.g. battery status change).
1667
1668           If you select "Y" here, you can disable actual use of the APM
1669           BIOS by passing the "apm=off" option to the kernel at boot time.
1670
1671           Note that the APM support is almost completely disabled for
1672           machines with more than one CPU.
1673
1674           In order to use APM, you will need supporting software. For location
1675           and more information, read <file:Documentation/power/pm.txt> and the
1676           Battery Powered Linux mini-HOWTO, available from
1677           <http://www.tldp.org/docs.html#howto>.
1678
1679           This driver does not spin down disk drives (see the hdparm(8)
1680           manpage ("man 8 hdparm") for that), and it doesn't turn off
1681           VESA-compliant "green" monitors.
1682
1683           This driver does not support the TI 4000M TravelMate and the ACER
1684           486/DX4/75 because they don't have compliant BIOSes. Many "green"
1685           desktop machines also don't have compliant BIOSes, and this driver
1686           may cause those machines to panic during the boot phase.
1687
1688           Generally, if you don't have a battery in your machine, there isn't
1689           much point in using this driver and you should say N. If you get
1690           random kernel OOPSes or reboots that don't seem to be related to
1691           anything, try disabling/enabling this option (or disabling/enabling
1692           APM in your BIOS).
1693
1694           Some other things you should try when experiencing seemingly random,
1695           "weird" problems:
1696
1697           1) make sure that you have enough swap space and that it is
1698           enabled.
1699           2) pass the "no-hlt" option to the kernel
1700           3) switch on floating point emulation in the kernel and pass
1701           the "no387" option to the kernel
1702           4) pass the "floppy=nodma" option to the kernel
1703           5) pass the "mem=4M" option to the kernel (thereby disabling
1704           all but the first 4 MB of RAM)
1705           6) make sure that the CPU is not over clocked.
1706           7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1707           8) disable the cache from your BIOS settings
1708           9) install a fan for the video card or exchange video RAM
1709           10) install a better fan for the CPU
1710           11) exchange RAM chips
1711           12) exchange the motherboard.
1712
1713           To compile this driver as a module, choose M here: the
1714           module will be called apm.
1715
1716 if APM
1717
1718 config APM_IGNORE_USER_SUSPEND
1719         bool "Ignore USER SUSPEND"
1720         ---help---
1721           This option will ignore USER SUSPEND requests. On machines with a
1722           compliant APM BIOS, you want to say N. However, on the NEC Versa M
1723           series notebooks, it is necessary to say Y because of a BIOS bug.
1724
1725 config APM_DO_ENABLE
1726         bool "Enable PM at boot time"
1727         ---help---
1728           Enable APM features at boot time. From page 36 of the APM BIOS
1729           specification: "When disabled, the APM BIOS does not automatically
1730           power manage devices, enter the Standby State, enter the Suspend
1731           State, or take power saving steps in response to CPU Idle calls."
1732           This driver will make CPU Idle calls when Linux is idle (unless this
1733           feature is turned off -- see "Do CPU IDLE calls", below). This
1734           should always save battery power, but more complicated APM features
1735           will be dependent on your BIOS implementation. You may need to turn
1736           this option off if your computer hangs at boot time when using APM
1737           support, or if it beeps continuously instead of suspending. Turn
1738           this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1739           T400CDT. This is off by default since most machines do fine without
1740           this feature.
1741
1742 config APM_CPU_IDLE
1743         bool "Make CPU Idle calls when idle"
1744         ---help---
1745           Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1746           On some machines, this can activate improved power savings, such as
1747           a slowed CPU clock rate, when the machine is idle. These idle calls
1748           are made after the idle loop has run for some length of time (e.g.,
1749           333 mS). On some machines, this will cause a hang at boot time or
1750           whenever the CPU becomes idle. (On machines with more than one CPU,
1751           this option does nothing.)
1752
1753 config APM_DISPLAY_BLANK
1754         bool "Enable console blanking using APM"
1755         ---help---
1756           Enable console blanking using the APM. Some laptops can use this to
1757           turn off the LCD backlight when the screen blanker of the Linux
1758           virtual console blanks the screen. Note that this is only used by
1759           the virtual console screen blanker, and won't turn off the backlight
1760           when using the X Window system. This also doesn't have anything to
1761           do with your VESA-compliant power-saving monitor. Further, this
1762           option doesn't work for all laptops -- it might not turn off your
1763           backlight at all, or it might print a lot of errors to the console,
1764           especially if you are using gpm.
1765
1766 config APM_ALLOW_INTS
1767         bool "Allow interrupts during APM BIOS calls"
1768         ---help---
1769           Normally we disable external interrupts while we are making calls to
1770           the APM BIOS as a measure to lessen the effects of a badly behaving
1771           BIOS implementation.  The BIOS should reenable interrupts if it
1772           needs to.  Unfortunately, some BIOSes do not -- especially those in
1773           many of the newer IBM Thinkpads.  If you experience hangs when you
1774           suspend, try setting this to Y.  Otherwise, say N.
1775
1776 endif # APM
1777
1778 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1779
1780 source "drivers/cpuidle/Kconfig"
1781
1782 source "drivers/idle/Kconfig"
1783
1784 endmenu
1785
1786
1787 menu "Bus options (PCI etc.)"
1788
1789 config PCI
1790         bool "PCI support"
1791         default y
1792         select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1793         ---help---
1794           Find out whether you have a PCI motherboard. PCI is the name of a
1795           bus system, i.e. the way the CPU talks to the other stuff inside
1796           your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1797           VESA. If you have PCI, say Y, otherwise N.
1798
1799 choice
1800         prompt "PCI access mode"
1801         depends on X86_32 && PCI
1802         default PCI_GOANY
1803         ---help---
1804           On PCI systems, the BIOS can be used to detect the PCI devices and
1805           determine their configuration. However, some old PCI motherboards
1806           have BIOS bugs and may crash if this is done. Also, some embedded
1807           PCI-based systems don't have any BIOS at all. Linux can also try to
1808           detect the PCI hardware directly without using the BIOS.
1809
1810           With this option, you can specify how Linux should detect the
1811           PCI devices. If you choose "BIOS", the BIOS will be used,
1812           if you choose "Direct", the BIOS won't be used, and if you
1813           choose "MMConfig", then PCI Express MMCONFIG will be used.
1814           If you choose "Any", the kernel will try MMCONFIG, then the
1815           direct access method and falls back to the BIOS if that doesn't
1816           work. If unsure, go with the default, which is "Any".
1817
1818 config PCI_GOBIOS
1819         bool "BIOS"
1820
1821 config PCI_GOMMCONFIG
1822         bool "MMConfig"
1823
1824 config PCI_GODIRECT
1825         bool "Direct"
1826
1827 config PCI_GOOLPC
1828         bool "OLPC"
1829         depends on OLPC
1830
1831 config PCI_GOANY
1832         bool "Any"
1833
1834 endchoice
1835
1836 config PCI_BIOS
1837         def_bool y
1838         depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1839
1840 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1841 config PCI_DIRECT
1842         def_bool y
1843         depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1844
1845 config PCI_MMCONFIG
1846         def_bool y
1847         depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1848
1849 config PCI_OLPC
1850         def_bool y
1851         depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1852
1853 config PCI_DOMAINS
1854         def_bool y
1855         depends on PCI
1856
1857 config PCI_MMCONFIG
1858         bool "Support mmconfig PCI config space access"
1859         depends on X86_64 && PCI && ACPI
1860
1861 config DMAR
1862         bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1863         depends on PCI_MSI && ACPI && EXPERIMENTAL
1864         help
1865           DMA remapping (DMAR) devices support enables independent address
1866           translations for Direct Memory Access (DMA) from devices.
1867           These DMA remapping devices are reported via ACPI tables
1868           and include PCI device scope covered by these DMA
1869           remapping devices.
1870
1871 config DMAR_DEFAULT_ON
1872         def_bool y
1873         prompt "Enable DMA Remapping Devices by default"
1874         depends on DMAR
1875         help
1876           Selecting this option will enable a DMAR device at boot time if
1877           one is found. If this option is not selected, DMAR support can
1878           be enabled by passing intel_iommu=on to the kernel. It is
1879           recommended you say N here while the DMAR code remains
1880           experimental.
1881
1882 config DMAR_BROKEN_GFX_WA
1883         def_bool n
1884         prompt "Workaround broken graphics drivers (going away soon)"
1885         depends on DMAR
1886         ---help---
1887           Current Graphics drivers tend to use physical address
1888           for DMA and avoid using DMA APIs. Setting this config
1889           option permits the IOMMU driver to set a unity map for
1890           all the OS-visible memory. Hence the driver can continue
1891           to use physical addresses for DMA, at least until this
1892           option is removed in the 2.6.32 kernel.
1893
1894 config DMAR_FLOPPY_WA
1895         def_bool y
1896         depends on DMAR
1897         ---help---
1898           Floppy disk drivers are known to bypass DMA API calls
1899           thereby failing to work when IOMMU is enabled. This
1900           workaround will setup a 1:1 mapping for the first
1901           16MiB to make floppy (an ISA device) work.
1902
1903 config INTR_REMAP
1904         bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1905         depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1906         ---help---
1907           Supports Interrupt remapping for IO-APIC and MSI devices.
1908           To use x2apic mode in the CPU's which support x2APIC enhancements or
1909           to support platforms with CPU's having > 8 bit APIC ID, say Y.
1910
1911 source "drivers/pci/pcie/Kconfig"
1912
1913 source "drivers/pci/Kconfig"
1914
1915 # x86_64 have no ISA slots, but do have ISA-style DMA.
1916 config ISA_DMA_API
1917         def_bool y
1918
1919 if X86_32
1920
1921 config ISA
1922         bool "ISA support"
1923         ---help---
1924           Find out whether you have ISA slots on your motherboard.  ISA is the
1925           name of a bus system, i.e. the way the CPU talks to the other stuff
1926           inside your box.  Other bus systems are PCI, EISA, MicroChannel
1927           (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
1928           newer boards don't support it.  If you have ISA, say Y, otherwise N.
1929
1930 config EISA
1931         bool "EISA support"
1932         depends on ISA
1933         ---help---
1934           The Extended Industry Standard Architecture (EISA) bus was
1935           developed as an open alternative to the IBM MicroChannel bus.
1936
1937           The EISA bus provided some of the features of the IBM MicroChannel
1938           bus while maintaining backward compatibility with cards made for
1939           the older ISA bus.  The EISA bus saw limited use between 1988 and
1940           1995 when it was made obsolete by the PCI bus.
1941
1942           Say Y here if you are building a kernel for an EISA-based machine.
1943
1944           Otherwise, say N.
1945
1946 source "drivers/eisa/Kconfig"
1947
1948 config MCA
1949         bool "MCA support"
1950         ---help---
1951           MicroChannel Architecture is found in some IBM PS/2 machines and
1952           laptops.  It is a bus system similar to PCI or ISA. See
1953           <file:Documentation/mca.txt> (and especially the web page given
1954           there) before attempting to build an MCA bus kernel.
1955
1956 source "drivers/mca/Kconfig"
1957
1958 config SCx200
1959         tristate "NatSemi SCx200 support"
1960         ---help---
1961           This provides basic support for National Semiconductor's
1962           (now AMD's) Geode processors.  The driver probes for the
1963           PCI-IDs of several on-chip devices, so its a good dependency
1964           for other scx200_* drivers.
1965
1966           If compiled as a module, the driver is named scx200.
1967
1968 config SCx200HR_TIMER
1969         tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1970         depends on SCx200 && GENERIC_TIME
1971         default y
1972         ---help---
1973           This driver provides a clocksource built upon the on-chip
1974           27MHz high-resolution timer.  Its also a workaround for
1975           NSC Geode SC-1100's buggy TSC, which loses time when the
1976           processor goes idle (as is done by the scheduler).  The
1977           other workaround is idle=poll boot option.
1978
1979 config GEODE_MFGPT_TIMER
1980         def_bool y
1981         prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1982         depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1983         ---help---
1984           This driver provides a clock event source based on the MFGPT
1985           timer(s) in the CS5535 and CS5536 companion chip for the geode.
1986           MFGPTs have a better resolution and max interval than the
1987           generic PIT, and are suitable for use as high-res timers.
1988
1989 config OLPC
1990         bool "One Laptop Per Child support"
1991         default n
1992         ---help---
1993           Add support for detecting the unique features of the OLPC
1994           XO hardware.
1995
1996 endif # X86_32
1997
1998 config K8_NB
1999         def_bool y
2000         depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
2001
2002 source "drivers/pcmcia/Kconfig"
2003
2004 source "drivers/pci/hotplug/Kconfig"
2005
2006 endmenu
2007
2008
2009 menu "Executable file formats / Emulations"
2010
2011 source "fs/Kconfig.binfmt"
2012
2013 config IA32_EMULATION
2014         bool "IA32 Emulation"
2015         depends on X86_64
2016         select COMPAT_BINFMT_ELF
2017         ---help---
2018           Include code to run 32-bit programs under a 64-bit kernel. You should
2019           likely turn this on, unless you're 100% sure that you don't have any
2020           32-bit programs left.
2021
2022 config IA32_AOUT
2023         tristate "IA32 a.out support"
2024         depends on IA32_EMULATION
2025         ---help---
2026           Support old a.out binaries in the 32bit emulation.
2027
2028 config COMPAT
2029         def_bool y
2030         depends on IA32_EMULATION
2031
2032 config COMPAT_FOR_U64_ALIGNMENT
2033         def_bool COMPAT
2034         depends on X86_64
2035
2036 config SYSVIPC_COMPAT
2037         def_bool y
2038         depends on COMPAT && SYSVIPC
2039
2040 endmenu
2041
2042
2043 config HAVE_ATOMIC_IOMAP
2044         def_bool y
2045         depends on X86_32
2046
2047 source "net/Kconfig"
2048
2049 source "drivers/Kconfig"
2050
2051 source "drivers/firmware/Kconfig"
2052
2053 source "fs/Kconfig"
2054
2055 source "arch/x86/Kconfig.debug"
2056
2057 source "security/Kconfig"
2058
2059 source "crypto/Kconfig"
2060
2061 source "arch/x86/kvm/Kconfig"
2062
2063 source "lib/Kconfig"