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