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 LZO_COMPRESS
 282         tristate
 283
 284 config LZO_DECOMPRESS
 285         tristate
 286
 287 config LZ4_COMPRESS
 288         tristate
 289
 290 config LZ4HC_COMPRESS
 291         tristate
 292
 293 config LZ4_DECOMPRESS
 294         tristate
 295
 296 config ZSTD_COMPRESS
 297         select XXHASH
 298         tristate
 299
 300 config ZSTD_DECOMPRESS
 301         select XXHASH
 302         tristate
 303
 304 source "lib/xz/Kconfig"
 305
 306 #
 307 # These all provide a common interface (hence the apparent duplication with
 308 # ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
 309 #
 310 config DECOMPRESS_GZIP
 311         select ZLIB_INFLATE
 312         tristate
 313
 314 config DECOMPRESS_BZIP2
 315         tristate
 316
 317 config DECOMPRESS_LZMA
 318         tristate
 319
 320 config DECOMPRESS_XZ
 321         select XZ_DEC
 322         tristate
 323
 324 config DECOMPRESS_LZO
 325         select LZO_DECOMPRESS
 326         tristate
 327
 328 config DECOMPRESS_LZ4
 329         select LZ4_DECOMPRESS
 330         tristate
 331
 332 #
 333 # Generic allocator support is selected if needed
 334 #
 335 config GENERIC_ALLOCATOR
 336         bool
 337
 338 #
 339 # reed solomon support is select'ed if needed
 340 #
 341 config REED_SOLOMON
 342         tristate
 343
 344 config REED_SOLOMON_ENC8
 345         bool
 346
 347 config REED_SOLOMON_DEC8
 348         bool
 349
 350 config REED_SOLOMON_ENC16
 351         bool
 352
 353 config REED_SOLOMON_DEC16
 354         bool
 355
 356 #
 357 # BCH support is selected if needed
 358 #
 359 config BCH
 360         tristate
 361
 362 config BCH_CONST_PARAMS
 363         bool
 364         help
 365           Drivers may select this option to force specific constant
 366           values for parameters 'm' (Galois field order) and 't'
 367           (error correction capability). Those specific values must
 368           be set by declaring default values for symbols BCH_CONST_M
 369           and BCH_CONST_T.
 370           Doing so will enable extra compiler optimizations,
 371           improving encoding and decoding performance up to 2x for
 372           usual (m,t) values (typically such that m*t < 200).
 373           When this option is selected, the BCH library supports
 374           only a single (m,t) configuration. This is mainly useful
 375           for NAND flash board drivers requiring known, fixed BCH
 376           parameters.
 377
 378 config BCH_CONST_M
 379         int
 380         range 5 15
 381         help
 382           Constant value for Galois field order 'm'. If 'k' is the
 383           number of data bits to protect, 'm' should be chosen such
 384           that (k + m*t) <= 2**m - 1.
 385           Drivers should declare a default value for this symbol if
 386           they select option BCH_CONST_PARAMS.
 387
 388 config BCH_CONST_T
 389         int
 390         help
 391           Constant value for error correction capability in bits 't'.
 392           Drivers should declare a default value for this symbol if
 393           they select option BCH_CONST_PARAMS.
 394
 395 #
 396 # Textsearch support is select'ed if needed
 397 #
 398 config TEXTSEARCH
 399         bool
 400
 401 config TEXTSEARCH_KMP
 402         tristate
 403
 404 config TEXTSEARCH_BM
 405         tristate
 406
 407 config TEXTSEARCH_FSM
 408         tristate
 409
 410 config BTREE
 411         bool
 412
 413 config INTERVAL_TREE
 414         bool
 415         help
 416           Simple, embeddable, interval-tree. Can find the start of an
 417           overlapping range in log(n) time and then iterate over all
 418           overlapping nodes. The algorithm is implemented as an
 419           augmented rbtree.
 420
 421           See:
 422
 423                 Documentation/rbtree.txt
 424
 425           for more information.
 426
 427 config XARRAY_MULTI
 428         bool
 429         help
 430           Support entries which occupy multiple consecutive indices in the
 431           XArray.
 432
 433 config ASSOCIATIVE_ARRAY
 434         bool
 435         help
 436           Generic associative array.  Can be searched and iterated over whilst
 437           it is being modified.  It is also reasonably quick to search and
 438           modify.  The algorithms are non-recursive, and the trees are highly
 439           capacious.
 440
 441           See:
 442
 443                 Documentation/core-api/assoc_array.rst
 444
 445           for more information.
 446
 447 config HAS_IOMEM
 448         bool
 449         depends on !NO_IOMEM
 450         select GENERIC_IO
 451         default y
 452
 453 config HAS_IOPORT_MAP
 454         bool
 455         depends on HAS_IOMEM && !NO_IOPORT_MAP
 456         default y
 457
 458 source "kernel/dma/Kconfig"
 459
 460 config SGL_ALLOC
 461         bool
 462         default n
 463
 464 config IOMMU_HELPER
 465         bool
 466
 467 config CHECK_SIGNATURE
 468         bool
 469
 470 config CPUMASK_OFFSTACK
 471         bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
 472         help
 473           Use dynamic allocation for cpumask_var_t, instead of putting
 474           them on the stack.  This is a bit more expensive, but avoids
 475           stack overflow.
 476
 477 config CPU_RMAP
 478         bool
 479         depends on SMP
 480
 481 config DQL
 482         bool
 483
 484 config GLOB
 485         bool
 486 #       This actually supports modular compilation, but the module overhead
 487 #       is ridiculous for the amount of code involved.  Until an out-of-tree
 488 #       driver asks for it, we'll just link it directly it into the kernel
 489 #       when required.  Since we're ignoring out-of-tree users, there's also
 490 #       no need bother prompting for a manual decision:
 491 #       prompt "glob_match() function"
 492         help
 493           This option provides a glob_match function for performing
 494           simple text pattern matching.  It originated in the ATA code
 495           to blacklist particular drive models, but other device drivers
 496           may need similar functionality.
 497
 498           All drivers in the Linux kernel tree that require this function
 499           should automatically select this option.  Say N unless you
 500           are compiling an out-of tree driver which tells you that it
 501           depends on this.
 502
 503 config GLOB_SELFTEST
 504         tristate "glob self-test on init"
 505         depends on GLOB
 506         help
 507           This option enables a simple self-test of the glob_match
 508           function on startup.  It is primarily useful for people
 509           working on the code to ensure they haven't introduced any
 510           regressions.
 511
 512           It only adds a little bit of code and slows kernel boot (or
 513           module load) by a small amount, so you're welcome to play with
 514           it, but you probably don't need it.
 515
 516 #
 517 # Netlink attribute parsing support is select'ed if needed
 518 #
 519 config NLATTR
 520         bool
 521
 522 #
 523 # Generic 64-bit atomic support is selected if needed
 524 #
 525 config GENERIC_ATOMIC64
 526        bool
 527
 528 config LRU_CACHE
 529         tristate
 530
 531 config CLZ_TAB
 532         bool
 533
 534 config DDR
 535         bool "JEDEC DDR data"
 536         help
 537           Data from JEDEC specs for DDR SDRAM memories,
 538           particularly the AC timing parameters and addressing
 539           information. This data is useful for drivers handling
 540           DDR SDRAM controllers.
 541
 542 config IRQ_POLL
 543         bool "IRQ polling library"
 544         help
 545           Helper library to poll interrupt mitigation using polling.
 546
 547 config MPILIB
 548         tristate
 549         select CLZ_TAB
 550         help
 551           Multiprecision maths library from GnuPG.
 552           It is used to implement RSA digital signature verification,
 553           which is used by IMA/EVM digital signature extension.
 554
 555 config SIGNATURE
 556         tristate
 557         depends on KEYS
 558         select CRYPTO
 559         select CRYPTO_SHA1
 560         select MPILIB
 561         help
 562           Digital signature verification. Currently only RSA is supported.
 563           Implementation is done using GnuPG MPI library
 564
 565 #
 566 # libfdt files, only selected if needed.
 567 #
 568 config LIBFDT
 569         bool
 570
 571 config OID_REGISTRY
 572         tristate
 573         help
 574           Enable fast lookup object identifier registry.
 575
 576 config UCS2_STRING
 577         tristate
 578
 579 source "lib/fonts/Kconfig"
 580
 581 config SG_SPLIT
 582         def_bool n
 583         help
 584          Provides a helper to split scatterlists into chunks, each chunk being
 585          a scatterlist. This should be selected by a driver or an API which
 586          whishes to split a scatterlist amongst multiple DMA channels.
 587
 588 config SG_POOL
 589         def_bool n
 590         help
 591          Provides a helper to allocate chained scatterlists. This should be
 592          selected by a driver or an API which whishes to allocate chained
 593          scatterlist.
 594
 595 #
 596 # sg chaining option
 597 #
 598
 599 config ARCH_NO_SG_CHAIN
 600         def_bool n
 601
 602 config ARCH_HAS_PMEM_API
 603         bool
 604
 605 # use memcpy to implement user copies for nommu architectures
 606 config UACCESS_MEMCPY
 607         bool
 608
 609 config ARCH_HAS_UACCESS_FLUSHCACHE
 610         bool
 611
 612 config ARCH_HAS_UACCESS_MCSAFE
 613         bool
 614
 615 # Temporary. Goes away when all archs are cleaned up
 616 config ARCH_STACKWALK
 617        bool
 618
 619 config STACKDEPOT
 620         bool
 621         select STACKTRACE
 622
 623 config SBITMAP
 624         bool
 625
 626 config PARMAN
 627         tristate "parman" if COMPILE_TEST
 628
 629 config STRING_SELFTEST
 630         tristate "Test string functions"
 631
 632 endmenu
 633
 634 config GENERIC_LIB_ASHLDI3
 635         bool
 636
 637 config GENERIC_LIB_ASHRDI3
 638         bool
 639
 640 config GENERIC_LIB_LSHRDI3
 641         bool
 642
 643 config GENERIC_LIB_MULDI3
 644         bool
 645
 646 config GENERIC_LIB_CMPDI2
 647         bool
 648
 649 config GENERIC_LIB_UCMPDI2
 650         bool
 651
 652 config OBJAGG
 653         tristate "objagg" if COMPILE_TEST