lib/Kconfig

   1 # SPDX-License-Identifier: GPL-2.0-only
   2 #
   3 # Library configuration
   4 #
   5
   6 config BINARY_PRINTF
   7         def_bool n
   8
   9 menu "Library routines"
  10
  11 config RAID6_PQ
  12         tristate
  13
  14 config RAID6_PQ_BENCHMARK
  15         bool "Automatically choose fastest RAID6 PQ functions"
  16         depends on RAID6_PQ
  17         default y
  18         help
  19           Benchmark all available RAID6 PQ functions on init and choose the
  20           fastest one.
  21
  22 config LINEAR_RANGES
  23         tristate
  24
  25 config PACKING
  26         bool "Generic bitfield packing and unpacking"
  27         select BITREVERSE
  28         default n
  29         help
  30           This option provides the packing() helper function, which permits
  31           converting bitfields between a CPU-usable representation and a
  32           memory representation that can have any combination of these quirks:
  33             - Is little endian (bytes are reversed within a 32-bit group)
  34             - The least-significant 32-bit word comes first (within a 64-bit
  35               group)
  36             - The most significant bit of a byte is at its right (bit 0 of a
  37               register description is numerically 2^7).
  38           Drivers may use these helpers to match the bit indices as described
  39           in the data sheets of the peripherals they are in control of.
  40
  41           When in doubt, say N.
  42
  43 config BITREVERSE
  44         tristate
  45
  46 config HAVE_ARCH_BITREVERSE
  47         bool
  48         default n
  49         help
  50           This option enables the use of hardware bit-reversal instructions on
  51           architectures which support such operations.
  52
  53 config ARCH_HAS_STRNCPY_FROM_USER
  54         bool
  55
  56 config ARCH_HAS_STRNLEN_USER
  57         bool
  58
  59 config GENERIC_STRNCPY_FROM_USER
  60         def_bool !ARCH_HAS_STRNCPY_FROM_USER
  61
  62 config GENERIC_STRNLEN_USER
  63         def_bool !ARCH_HAS_STRNLEN_USER
  64
  65 config GENERIC_NET_UTILS
  66         bool
  67
  68 source "lib/math/Kconfig"
  69
  70 config NO_GENERIC_PCI_IOPORT_MAP
  71         bool
  72
  73 config GENERIC_IOMAP
  74         bool
  75         select GENERIC_PCI_IOMAP
  76
  77 config STMP_DEVICE
  78         bool
  79
  80 config ARCH_USE_CMPXCHG_LOCKREF
  81         bool
  82
  83 config ARCH_HAS_FAST_MULTIPLIER
  84         bool
  85
  86 config ARCH_USE_SYM_ANNOTATIONS
  87         bool
  88
  89 config INDIRECT_PIO
  90         bool "Access I/O in non-MMIO mode"
  91         depends on ARM64
  92         depends on HAS_IOPORT
  93         help
  94           On some platforms where no separate I/O space exists, there are I/O
  95           hosts which can not be accessed in MMIO mode. Using the logical PIO
  96           mechanism, the host-local I/O resource can be mapped into system
  97           logic PIO space shared with MMIO hosts, such as PCI/PCIe, then the
  98           system can access the I/O devices with the mapped-logic PIO through
  99           I/O accessors.
 100
 101           This way has relatively little I/O performance cost. Please make
 102           sure your devices really need this configure item enabled.
 103
 104           When in doubt, say N.
 105
 106 config INDIRECT_IOMEM
 107         bool
 108         help
 109           This is selected by other options/architectures to provide the
 110           emulated iomem accessors.
 111
 112 config INDIRECT_IOMEM_FALLBACK
 113         bool
 114         depends on INDIRECT_IOMEM
 115         help
 116           If INDIRECT_IOMEM is selected, this enables falling back to plain
 117           mmio accesses when the IO memory address is not a registered
 118           emulated region.
 119
 120 config TRACE_MMIO_ACCESS
 121         bool "Register read/write tracing"
 122         depends on TRACING && ARCH_HAVE_TRACE_MMIO_ACCESS
 123         help
 124           Create tracepoints for MMIO read/write operations. These trace events
 125           can be used for logging all MMIO read/write operations.
 126
 127 source "lib/crypto/Kconfig"
 128
 129 config CRC_CCITT
 130         tristate "CRC-CCITT functions"
 131         help
 132           This option is provided for the case where no in-kernel-tree
 133           modules require CRC-CCITT functions, but a module built outside
 134           the kernel tree does. Such modules that use library CRC-CCITT
 135           functions require M here.
 136
 137 config CRC16
 138         tristate "CRC16 functions"
 139         help
 140           This option is provided for the case where no in-kernel-tree
 141           modules require CRC16 functions, but a module built outside
 142           the kernel tree does. Such modules that use library CRC16
 143           functions require M here.
 144
 145 config CRC_T10DIF
 146         tristate "CRC calculation for the T10 Data Integrity Field"
 147         select CRYPTO
 148         select CRYPTO_CRCT10DIF
 149         help
 150           This option is only needed if a module that's not in the
 151           kernel tree needs to calculate CRC checks for use with the
 152           SCSI data integrity subsystem.
 153
 154 config CRC64_ROCKSOFT
 155         tristate "CRC calculation for the Rocksoft model CRC64"
 156         select CRC64
 157         select CRYPTO
 158         select CRYPTO_CRC64_ROCKSOFT
 159         help
 160           This option provides a CRC64 API to a registered crypto driver.
 161           This is used with the block layer's data integrity subsystem.
 162
 163 config CRC_ITU_T
 164         tristate "CRC ITU-T V.41 functions"
 165         help
 166           This option is provided for the case where no in-kernel-tree
 167           modules require CRC ITU-T V.41 functions, but a module built outside
 168           the kernel tree does. Such modules that use library CRC ITU-T V.41
 169           functions require M here.
 170
 171 config CRC32
 172         tristate "CRC32/CRC32c functions"
 173         default y
 174         select BITREVERSE
 175         help
 176           This option is provided for the case where no in-kernel-tree
 177           modules require CRC32/CRC32c functions, but a module built outside
 178           the kernel tree does. Such modules that use library CRC32/CRC32c
 179           functions require M here.
 180
 181 config CRC32_SELFTEST
 182         tristate "CRC32 perform self test on init"
 183         depends on CRC32
 184         help
 185           This option enables the CRC32 library functions to perform a
 186           self test on initialization. The self test computes crc32_le
 187           and crc32_be over byte strings with random alignment and length
 188           and computes the total elapsed time and number of bytes processed.
 189
 190 choice
 191         prompt "CRC32 implementation"
 192         depends on CRC32
 193         default CRC32_SLICEBY8
 194         help
 195           This option allows a kernel builder to override the default choice
 196           of CRC32 algorithm.  Choose the default ("slice by 8") unless you
 197           know that you need one of the others.
 198
 199 config CRC32_SLICEBY8
 200         bool "Slice by 8 bytes"
 201         help
 202           Calculate checksum 8 bytes at a time with a clever slicing algorithm.
 203           This is the fastest algorithm, but comes with a 8KiB lookup table.
 204           Most modern processors have enough cache to hold this table without
 205           thrashing the cache.
 206
 207           This is the default implementation choice.  Choose this one unless
 208           you have a good reason not to.
 209
 210 config CRC32_SLICEBY4
 211         bool "Slice by 4 bytes"
 212         help
 213           Calculate checksum 4 bytes at a time with a clever slicing algorithm.
 214           This is a bit slower than slice by 8, but has a smaller 4KiB lookup
 215           table.
 216
 217           Only choose this option if you know what you are doing.
 218
 219 config CRC32_SARWATE
 220         bool "Sarwate's Algorithm (one byte at a time)"
 221         help
 222           Calculate checksum a byte at a time using Sarwate's algorithm.  This
 223           is not particularly fast, but has a small 256 byte lookup table.
 224
 225           Only choose this option if you know what you are doing.
 226
 227 config CRC32_BIT
 228         bool "Classic Algorithm (one bit at a time)"
 229         help
 230           Calculate checksum one bit at a time.  This is VERY slow, but has
 231           no lookup table.  This is provided as a debugging option.
 232
 233           Only choose this option if you are debugging crc32.
 234
 235 endchoice
 236
 237 config CRC64
 238         tristate "CRC64 functions"
 239         help
 240           This option is provided for the case where no in-kernel-tree
 241           modules require CRC64 functions, but a module built outside
 242           the kernel tree does. Such modules that use library CRC64
 243           functions require M here.
 244
 245 config CRC4
 246         tristate "CRC4 functions"
 247         help
 248           This option is provided for the case where no in-kernel-tree
 249           modules require CRC4 functions, but a module built outside
 250           the kernel tree does. Such modules that use library CRC4
 251           functions require M here.
 252
 253 config CRC7
 254         tristate "CRC7 functions"
 255         help
 256           This option is provided for the case where no in-kernel-tree
 257           modules require CRC7 functions, but a module built outside
 258           the kernel tree does. Such modules that use library CRC7
 259           functions require M here.
 260
 261 config LIBCRC32C
 262         tristate "CRC32c (Castagnoli, et al) Cyclic Redundancy-Check"
 263         select CRYPTO
 264         select CRYPTO_CRC32C
 265         help
 266           This option is provided for the case where no in-kernel-tree
 267           modules require CRC32c functions, but a module built outside the
 268           kernel tree does. Such modules that use library CRC32c functions
 269           require M here.  See Castagnoli93.
 270           Module will be libcrc32c.
 271
 272 config CRC8
 273         tristate "CRC8 function"
 274         help
 275           This option provides CRC8 function. Drivers may select this
 276           when they need to do cyclic redundancy check according CRC8
 277           algorithm. Module will be called crc8.
 278
 279 config XXHASH
 280         tristate
 281
 282 config AUDIT_GENERIC
 283         bool
 284         depends on AUDIT && !AUDIT_ARCH
 285         default y
 286
 287 config AUDIT_ARCH_COMPAT_GENERIC
 288         bool
 289         default n
 290
 291 config AUDIT_COMPAT_GENERIC
 292         bool
 293         depends on AUDIT_GENERIC && AUDIT_ARCH_COMPAT_GENERIC && COMPAT
 294         default y
 295
 296 config RANDOM32_SELFTEST
 297         bool "PRNG perform self test on init"
 298         help
 299           This option enables the 32 bit PRNG library functions to perform a
 300           self test on initialization.
 301
 302 #
 303 # compression support is select'ed if needed
 304 #
 305 config 842_COMPRESS
 306         select CRC32
 307         tristate
 308
 309 config 842_DECOMPRESS
 310         select CRC32
 311         tristate
 312
 313 config ZLIB_INFLATE
 314         tristate
 315
 316 config ZLIB_DEFLATE
 317         tristate
 318         select BITREVERSE
 319
 320 config ZLIB_DFLTCC
 321         def_bool y
 322         depends on S390
 323         prompt "Enable s390x DEFLATE CONVERSION CALL support for kernel zlib"
 324         help
 325          Enable s390x hardware support for zlib in the kernel.
 326
 327 config LZO_COMPRESS
 328         tristate
 329
 330 config LZO_DECOMPRESS
 331         tristate
 332
 333 config LZ4_COMPRESS
 334         tristate
 335
 336 config LZ4HC_COMPRESS
 337         tristate
 338
 339 config LZ4_DECOMPRESS
 340         tristate
 341
 342 config ZSTD_COMMON
 343         select XXHASH
 344         tristate
 345
 346 config ZSTD_COMPRESS
 347         select ZSTD_COMMON
 348         tristate
 349
 350 config ZSTD_DECOMPRESS
 351         select ZSTD_COMMON
 352         tristate
 353
 354 source "lib/xz/Kconfig"
 355
 356 #
 357 # These all provide a common interface (hence the apparent duplication with
 358 # ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
 359 #
 360 config DECOMPRESS_GZIP
 361         select ZLIB_INFLATE
 362         tristate
 363
 364 config DECOMPRESS_BZIP2
 365         tristate
 366
 367 config DECOMPRESS_LZMA
 368         tristate
 369
 370 config DECOMPRESS_XZ
 371         select XZ_DEC
 372         tristate
 373
 374 config DECOMPRESS_LZO
 375         select LZO_DECOMPRESS
 376         tristate
 377
 378 config DECOMPRESS_LZ4
 379         select LZ4_DECOMPRESS
 380         tristate
 381
 382 config DECOMPRESS_ZSTD
 383         select ZSTD_DECOMPRESS
 384         tristate
 385
 386 #
 387 # Generic allocator support is selected if needed
 388 #
 389 config GENERIC_ALLOCATOR
 390         bool
 391
 392 #
 393 # reed solomon support is select'ed if needed
 394 #
 395 config REED_SOLOMON
 396         tristate
 397
 398 config REED_SOLOMON_ENC8
 399         bool
 400
 401 config REED_SOLOMON_DEC8
 402         bool
 403
 404 config REED_SOLOMON_ENC16
 405         bool
 406
 407 config REED_SOLOMON_DEC16
 408         bool
 409
 410 #
 411 # BCH support is selected if needed
 412 #
 413 config BCH
 414         tristate
 415         select BITREVERSE
 416
 417 config BCH_CONST_PARAMS
 418         bool
 419         help
 420           Drivers may select this option to force specific constant
 421           values for parameters 'm' (Galois field order) and 't'
 422           (error correction capability). Those specific values must
 423           be set by declaring default values for symbols BCH_CONST_M
 424           and BCH_CONST_T.
 425           Doing so will enable extra compiler optimizations,
 426           improving encoding and decoding performance up to 2x for
 427           usual (m,t) values (typically such that m*t < 200).
 428           When this option is selected, the BCH library supports
 429           only a single (m,t) configuration. This is mainly useful
 430           for NAND flash board drivers requiring known, fixed BCH
 431           parameters.
 432
 433 config BCH_CONST_M
 434         int
 435         range 5 15
 436         help
 437           Constant value for Galois field order 'm'. If 'k' is the
 438           number of data bits to protect, 'm' should be chosen such
 439           that (k + m*t) <= 2**m - 1.
 440           Drivers should declare a default value for this symbol if
 441           they select option BCH_CONST_PARAMS.
 442
 443 config BCH_CONST_T
 444         int
 445         help
 446           Constant value for error correction capability in bits 't'.
 447           Drivers should declare a default value for this symbol if
 448           they select option BCH_CONST_PARAMS.
 449
 450 #
 451 # Textsearch support is select'ed if needed
 452 #
 453 config TEXTSEARCH
 454         bool
 455
 456 config TEXTSEARCH_KMP
 457         tristate
 458
 459 config TEXTSEARCH_BM
 460         tristate
 461
 462 config TEXTSEARCH_FSM
 463         tristate
 464
 465 config BTREE
 466         bool
 467
 468 config INTERVAL_TREE
 469         bool
 470         help
 471           Simple, embeddable, interval-tree. Can find the start of an
 472           overlapping range in log(n) time and then iterate over all
 473           overlapping nodes. The algorithm is implemented as an
 474           augmented rbtree.
 475
 476           See:
 477
 478                 Documentation/core-api/rbtree.rst
 479
 480           for more information.
 481
 482 config INTERVAL_TREE_SPAN_ITER
 483         bool
 484         depends on INTERVAL_TREE
 485
 486 config XARRAY_MULTI
 487         bool
 488         help
 489           Support entries which occupy multiple consecutive indices in the
 490           XArray.
 491
 492 config ASSOCIATIVE_ARRAY
 493         bool
 494         help
 495           Generic associative array.  Can be searched and iterated over whilst
 496           it is being modified.  It is also reasonably quick to search and
 497           modify.  The algorithms are non-recursive, and the trees are highly
 498           capacious.
 499
 500           See:
 501
 502                 Documentation/core-api/assoc_array.rst
 503
 504           for more information.
 505
 506 config CLOSURES
 507         bool
 508
 509 config HAS_IOMEM
 510         bool
 511         depends on !NO_IOMEM
 512         default y
 513
 514 config HAS_IOPORT
 515         bool
 516
 517 config HAS_IOPORT_MAP
 518         bool
 519         depends on HAS_IOMEM && !NO_IOPORT_MAP
 520         default y
 521
 522 source "kernel/dma/Kconfig"
 523
 524 config SGL_ALLOC
 525         bool
 526         default n
 527
 528 config IOMMU_HELPER
 529         bool
 530
 531 config CHECK_SIGNATURE
 532         bool
 533
 534 config CPUMASK_OFFSTACK
 535         bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
 536         help
 537           Use dynamic allocation for cpumask_var_t, instead of putting
 538           them on the stack.  This is a bit more expensive, but avoids
 539           stack overflow.
 540
 541 config FORCE_NR_CPUS
 542        bool "Set number of CPUs at compile time"
 543        depends on SMP && EXPERT && !COMPILE_TEST
 544        help
 545          Say Yes if you have NR_CPUS set to an actual number of possible
 546          CPUs in your system, not to a default value. This forces the core
 547          code to rely on compile-time value and optimize kernel routines
 548          better.
 549
 550 config CPU_RMAP
 551         bool
 552         depends on SMP
 553
 554 config DQL
 555         bool
 556
 557 config GLOB
 558         bool
 559 #       This actually supports modular compilation, but the module overhead
 560 #       is ridiculous for the amount of code involved.  Until an out-of-tree
 561 #       driver asks for it, we'll just link it directly it into the kernel
 562 #       when required.  Since we're ignoring out-of-tree users, there's also
 563 #       no need bother prompting for a manual decision:
 564 #       prompt "glob_match() function"
 565         help
 566           This option provides a glob_match function for performing
 567           simple text pattern matching.  It originated in the ATA code
 568           to blacklist particular drive models, but other device drivers
 569           may need similar functionality.
 570
 571           All drivers in the Linux kernel tree that require this function
 572           should automatically select this option.  Say N unless you
 573           are compiling an out-of tree driver which tells you that it
 574           depends on this.
 575
 576 config GLOB_SELFTEST
 577         tristate "glob self-test on init"
 578         depends on GLOB
 579         help
 580           This option enables a simple self-test of the glob_match
 581           function on startup.  It is primarily useful for people
 582           working on the code to ensure they haven't introduced any
 583           regressions.
 584
 585           It only adds a little bit of code and slows kernel boot (or
 586           module load) by a small amount, so you're welcome to play with
 587           it, but you probably don't need it.
 588
 589 #
 590 # Netlink attribute parsing support is select'ed if needed
 591 #
 592 config NLATTR
 593         bool
 594
 595 #
 596 # Generic 64-bit atomic support is selected if needed
 597 #
 598 config GENERIC_ATOMIC64
 599        bool
 600
 601 config LRU_CACHE
 602         tristate
 603
 604 config CLZ_TAB
 605         bool
 606
 607 config IRQ_POLL
 608         bool "IRQ polling library"
 609         help
 610           Helper library to poll interrupt mitigation using polling.
 611
 612 config MPILIB
 613         tristate
 614         select CLZ_TAB
 615         help
 616           Multiprecision maths library from GnuPG.
 617           It is used to implement RSA digital signature verification,
 618           which is used by IMA/EVM digital signature extension.
 619
 620 config SIGNATURE
 621         tristate
 622         depends on KEYS
 623         select CRYPTO
 624         select CRYPTO_SHA1
 625         select MPILIB
 626         help
 627           Digital signature verification. Currently only RSA is supported.
 628           Implementation is done using GnuPG MPI library
 629
 630 config DIMLIB
 631         bool
 632         help
 633           Dynamic Interrupt Moderation library.
 634           Implements an algorithm for dynamically changing CQ moderation values
 635           according to run time performance.
 636
 637 #
 638 # libfdt files, only selected if needed.
 639 #
 640 config LIBFDT
 641         bool
 642
 643 config OID_REGISTRY
 644         tristate
 645         help
 646           Enable fast lookup object identifier registry.
 647
 648 config UCS2_STRING
 649         tristate
 650
 651 #
 652 # generic vdso
 653 #
 654 source "lib/vdso/Kconfig"
 655
 656 source "lib/fonts/Kconfig"
 657
 658 config SG_SPLIT
 659         def_bool n
 660         help
 661          Provides a helper to split scatterlists into chunks, each chunk being
 662          a scatterlist. This should be selected by a driver or an API which
 663          whishes to split a scatterlist amongst multiple DMA channels.
 664
 665 config SG_POOL
 666         def_bool n
 667         help
 668          Provides a helper to allocate chained scatterlists. This should be
 669          selected by a driver or an API which whishes to allocate chained
 670          scatterlist.
 671
 672 #
 673 # sg chaining option
 674 #
 675
 676 config ARCH_NO_SG_CHAIN
 677         def_bool n
 678
 679 config ARCH_HAS_PMEM_API
 680         bool
 681
 682 config MEMREGION
 683         bool
 684
 685 config ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
 686         bool
 687
 688 config ARCH_HAS_MEMREMAP_COMPAT_ALIGN
 689         bool
 690
 691 # use memcpy to implement user copies for nommu architectures
 692 config UACCESS_MEMCPY
 693         bool
 694
 695 config ARCH_HAS_UACCESS_FLUSHCACHE
 696         bool
 697
 698 # arch has a concept of a recoverable synchronous exception due to a
 699 # memory-read error like x86 machine-check or ARM data-abort, and
 700 # implements copy_mc_to_{user,kernel} to abort and report
 701 # 'bytes-transferred' if that exception fires when accessing the source
 702 # buffer.
 703 config ARCH_HAS_COPY_MC
 704         bool
 705
 706 # Temporary. Goes away when all archs are cleaned up
 707 config ARCH_STACKWALK
 708        bool
 709
 710 config STACKDEPOT
 711         bool
 712         select STACKTRACE
 713         help
 714           Stack depot: stack trace storage that avoids duplication
 715
 716 config STACKDEPOT_ALWAYS_INIT
 717         bool
 718         select STACKDEPOT
 719         help
 720           Always initialize stack depot during early boot
 721
 722 config STACKDEPOT_MAX_FRAMES
 723         int "Maximum number of frames in trace saved in stack depot"
 724         range 1 256
 725         default 64
 726         depends on STACKDEPOT
 727
 728 config REF_TRACKER
 729         bool
 730         depends on STACKTRACE_SUPPORT
 731         select STACKDEPOT
 732
 733 config SBITMAP
 734         bool
 735
 736 config PARMAN
 737         tristate "parman" if COMPILE_TEST
 738
 739 config OBJAGG
 740         tristate "objagg" if COMPILE_TEST
 741
 742 config LWQ_TEST
 743         bool "Boot-time test for lwq queuing"
 744         help
 745           Run boot-time test of light-weight queuing.
 746
 747 endmenu
 748
 749 config GENERIC_IOREMAP
 750         bool
 751
 752 config GENERIC_LIB_ASHLDI3
 753         bool
 754
 755 config GENERIC_LIB_ASHRDI3
 756         bool
 757
 758 config GENERIC_LIB_LSHRDI3
 759         bool
 760
 761 config GENERIC_LIB_MULDI3
 762         bool
 763
 764 config GENERIC_LIB_CMPDI2
 765         bool
 766
 767 config GENERIC_LIB_UCMPDI2
 768         bool
 769
 770 config GENERIC_LIB_DEVMEM_IS_ALLOWED
 771         bool
 772
 773 config PLDMFW
 774         bool
 775         default n
 776
 777 config ASN1_ENCODER
 778        tristate
 779
 780 config POLYNOMIAL
 781        tristate
 782
 783 config FIRMWARE_TABLE
 784         bool