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