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 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         help
  93           On some platforms where no separate I/O space exists, there are I/O
  94           hosts which can not be accessed in MMIO mode. Using the logical PIO
  95           mechanism, the host-local I/O resource can be mapped into system
  96           logic PIO space shared with MMIO hosts, such as PCI/PCIe, then the
  97           system can access the I/O devices with the mapped-logic PIO through
  98           I/O accessors.
  99
 100           This way has relatively little I/O performance cost. Please make
 101           sure your devices really need this configure item enabled.
 102
 103           When in doubt, say N.
 104
 105 config CRC_CCITT
 106         tristate "CRC-CCITT functions"
 107         help
 108           This option is provided for the case where no in-kernel-tree
 109           modules require CRC-CCITT functions, but a module built outside
 110           the kernel tree does. Such modules that use library CRC-CCITT
 111           functions require M here.
 112
 113 config CRC16
 114         tristate "CRC16 functions"
 115         help
 116           This option is provided for the case where no in-kernel-tree
 117           modules require CRC16 functions, but a module built outside
 118           the kernel tree does. Such modules that use library CRC16
 119           functions require M here.
 120
 121 config CRC_T10DIF
 122         tristate "CRC calculation for the T10 Data Integrity Field"
 123         select CRYPTO
 124         select CRYPTO_CRCT10DIF
 125         help
 126           This option is only needed if a module that's not in the
 127           kernel tree needs to calculate CRC checks for use with the
 128           SCSI data integrity subsystem.
 129
 130 config CRC_ITU_T
 131         tristate "CRC ITU-T V.41 functions"
 132         help
 133           This option is provided for the case where no in-kernel-tree
 134           modules require CRC ITU-T V.41 functions, but a module built outside
 135           the kernel tree does. Such modules that use library CRC ITU-T V.41
 136           functions require M here.
 137
 138 config CRC32
 139         tristate "CRC32/CRC32c functions"
 140         default y
 141         select BITREVERSE
 142         help
 143           This option is provided for the case where no in-kernel-tree
 144           modules require CRC32/CRC32c functions, but a module built outside
 145           the kernel tree does. Such modules that use library CRC32/CRC32c
 146           functions require M here.
 147
 148 config CRC32_SELFTEST
 149         tristate "CRC32 perform self test on init"
 150         depends on CRC32
 151         help
 152           This option enables the CRC32 library functions to perform a
 153           self test on initialization. The self test computes crc32_le
 154           and crc32_be over byte strings with random alignment and length
 155           and computes the total elapsed time and number of bytes processed.
 156
 157 choice
 158         prompt "CRC32 implementation"
 159         depends on CRC32
 160         default CRC32_SLICEBY8
 161         help
 162           This option allows a kernel builder to override the default choice
 163           of CRC32 algorithm.  Choose the default ("slice by 8") unless you
 164           know that you need one of the others.
 165
 166 config CRC32_SLICEBY8
 167         bool "Slice by 8 bytes"
 168         help
 169           Calculate checksum 8 bytes at a time with a clever slicing algorithm.
 170           This is the fastest algorithm, but comes with a 8KiB lookup table.
 171           Most modern processors have enough cache to hold this table without
 172           thrashing the cache.
 173
 174           This is the default implementation choice.  Choose this one unless
 175           you have a good reason not to.
 176
 177 config CRC32_SLICEBY4
 178         bool "Slice by 4 bytes"
 179         help
 180           Calculate checksum 4 bytes at a time with a clever slicing algorithm.
 181           This is a bit slower than slice by 8, but has a smaller 4KiB lookup
 182           table.
 183
 184           Only choose this option if you know what you are doing.
 185
 186 config CRC32_SARWATE
 187         bool "Sarwate's Algorithm (one byte at a time)"
 188         help
 189           Calculate checksum a byte at a time using Sarwate's algorithm.  This
 190           is not particularly fast, but has a small 256 byte lookup table.
 191
 192           Only choose this option if you know what you are doing.
 193
 194 config CRC32_BIT
 195         bool "Classic Algorithm (one bit at a time)"
 196         help
 197           Calculate checksum one bit at a time.  This is VERY slow, but has
 198           no lookup table.  This is provided as a debugging option.
 199
 200           Only choose this option if you are debugging crc32.
 201
 202 endchoice
 203
 204 config CRC64
 205         tristate "CRC64 functions"
 206         help
 207           This option is provided for the case where no in-kernel-tree
 208           modules require CRC64 functions, but a module built outside
 209           the kernel tree does. Such modules that use library CRC64
 210           functions require M here.
 211
 212 config CRC4
 213         tristate "CRC4 functions"
 214         help
 215           This option is provided for the case where no in-kernel-tree
 216           modules require CRC4 functions, but a module built outside
 217           the kernel tree does. Such modules that use library CRC4
 218           functions require M here.
 219
 220 config CRC7
 221         tristate "CRC7 functions"
 222         help
 223           This option is provided for the case where no in-kernel-tree
 224           modules require CRC7 functions, but a module built outside
 225           the kernel tree does. Such modules that use library CRC7
 226           functions require M here.
 227
 228 config LIBCRC32C
 229         tristate "CRC32c (Castagnoli, et al) Cyclic Redundancy-Check"
 230         select CRYPTO
 231         select CRYPTO_CRC32C
 232         help
 233           This option is provided for the case where no in-kernel-tree
 234           modules require CRC32c functions, but a module built outside the
 235           kernel tree does. Such modules that use library CRC32c functions
 236           require M here.  See Castagnoli93.
 237           Module will be libcrc32c.
 238
 239 config CRC8
 240         tristate "CRC8 function"
 241         help
 242           This option provides CRC8 function. Drivers may select this
 243           when they need to do cyclic redundancy check according CRC8
 244           algorithm. Module will be called crc8.
 245
 246 config XXHASH
 247         tristate
 248
 249 config AUDIT_GENERIC
 250         bool
 251         depends on AUDIT && !AUDIT_ARCH
 252         default y
 253
 254 config AUDIT_ARCH_COMPAT_GENERIC
 255         bool
 256         default n
 257
 258 config AUDIT_COMPAT_GENERIC
 259         bool
 260         depends on AUDIT_GENERIC && AUDIT_ARCH_COMPAT_GENERIC && COMPAT
 261         default y
 262
 263 config RANDOM32_SELFTEST
 264         bool "PRNG perform self test on init"
 265         help
 266           This option enables the 32 bit PRNG library functions to perform a
 267           self test on initialization.
 268
 269 #
 270 # compression support is select'ed if needed
 271 #
 272 config 842_COMPRESS
 273         select CRC32
 274         tristate
 275
 276 config 842_DECOMPRESS
 277         select CRC32
 278         tristate
 279
 280 config ZLIB_INFLATE
 281         tristate
 282
 283 config ZLIB_DEFLATE
 284         tristate
 285         select BITREVERSE
 286
 287 config ZLIB_DFLTCC
 288         def_bool y
 289         depends on S390
 290         prompt "Enable s390x DEFLATE CONVERSION CALL support for kernel zlib"
 291         help
 292          Enable s390x hardware support for zlib in the kernel.
 293
 294 config LZO_COMPRESS
 295         tristate
 296
 297 config LZO_DECOMPRESS
 298         tristate
 299
 300 config LZ4_COMPRESS
 301         tristate
 302
 303 config LZ4HC_COMPRESS
 304         tristate
 305
 306 config LZ4_DECOMPRESS
 307         tristate
 308
 309 config ZSTD_COMPRESS
 310         select XXHASH
 311         tristate
 312
 313 config ZSTD_DECOMPRESS
 314         select XXHASH
 315         tristate
 316
 317 source "lib/xz/Kconfig"
 318
 319 #
 320 # These all provide a common interface (hence the apparent duplication with
 321 # ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
 322 #
 323 config DECOMPRESS_GZIP
 324         select ZLIB_INFLATE
 325         tristate
 326
 327 config DECOMPRESS_BZIP2
 328         tristate
 329
 330 config DECOMPRESS_LZMA
 331         tristate
 332
 333 config DECOMPRESS_XZ
 334         select XZ_DEC
 335         tristate
 336
 337 config DECOMPRESS_LZO
 338         select LZO_DECOMPRESS
 339         tristate
 340
 341 config DECOMPRESS_LZ4
 342         select LZ4_DECOMPRESS
 343         tristate
 344
 345 config DECOMPRESS_ZSTD
 346         select ZSTD_DECOMPRESS
 347         tristate
 348
 349 #
 350 # Generic allocator support is selected if needed
 351 #
 352 config GENERIC_ALLOCATOR
 353         bool
 354
 355 #
 356 # reed solomon support is select'ed if needed
 357 #
 358 config REED_SOLOMON
 359         tristate
 360
 361 config REED_SOLOMON_ENC8
 362         bool
 363
 364 config REED_SOLOMON_DEC8
 365         bool
 366
 367 config REED_SOLOMON_ENC16
 368         bool
 369
 370 config REED_SOLOMON_DEC16
 371         bool
 372
 373 #
 374 # BCH support is selected if needed
 375 #
 376 config BCH
 377         tristate
 378
 379 config BCH_CONST_PARAMS
 380         bool
 381         help
 382           Drivers may select this option to force specific constant
 383           values for parameters 'm' (Galois field order) and 't'
 384           (error correction capability). Those specific values must
 385           be set by declaring default values for symbols BCH_CONST_M
 386           and BCH_CONST_T.
 387           Doing so will enable extra compiler optimizations,
 388           improving encoding and decoding performance up to 2x for
 389           usual (m,t) values (typically such that m*t < 200).
 390           When this option is selected, the BCH library supports
 391           only a single (m,t) configuration. This is mainly useful
 392           for NAND flash board drivers requiring known, fixed BCH
 393           parameters.
 394
 395 config BCH_CONST_M
 396         int
 397         range 5 15
 398         help
 399           Constant value for Galois field order 'm'. If 'k' is the
 400           number of data bits to protect, 'm' should be chosen such
 401           that (k + m*t) <= 2**m - 1.
 402           Drivers should declare a default value for this symbol if
 403           they select option BCH_CONST_PARAMS.
 404
 405 config BCH_CONST_T
 406         int
 407         help
 408           Constant value for error correction capability in bits 't'.
 409           Drivers should declare a default value for this symbol if
 410           they select option BCH_CONST_PARAMS.
 411
 412 #
 413 # Textsearch support is select'ed if needed
 414 #
 415 config TEXTSEARCH
 416         bool
 417
 418 config TEXTSEARCH_KMP
 419         tristate
 420
 421 config TEXTSEARCH_BM
 422         tristate
 423
 424 config TEXTSEARCH_FSM
 425         tristate
 426
 427 config BTREE
 428         bool
 429
 430 config INTERVAL_TREE
 431         bool
 432         help
 433           Simple, embeddable, interval-tree. Can find the start of an
 434           overlapping range in log(n) time and then iterate over all
 435           overlapping nodes. The algorithm is implemented as an
 436           augmented rbtree.
 437
 438           See:
 439
 440                 Documentation/core-api/rbtree.rst
 441
 442           for more information.
 443
 444 config XARRAY_MULTI
 445         bool
 446         help
 447           Support entries which occupy multiple consecutive indices in the
 448           XArray.
 449
 450 config ASSOCIATIVE_ARRAY
 451         bool
 452         help
 453           Generic associative array.  Can be searched and iterated over whilst
 454           it is being modified.  It is also reasonably quick to search and
 455           modify.  The algorithms are non-recursive, and the trees are highly
 456           capacious.
 457
 458           See:
 459
 460                 Documentation/core-api/assoc_array.rst
 461
 462           for more information.
 463
 464 config HAS_IOMEM
 465         bool
 466         depends on !NO_IOMEM
 467         default y
 468
 469 config HAS_IOPORT_MAP
 470         bool
 471         depends on HAS_IOMEM && !NO_IOPORT_MAP
 472         default y
 473
 474 source "kernel/dma/Kconfig"
 475
 476 config SGL_ALLOC
 477         bool
 478         default n
 479
 480 config IOMMU_HELPER
 481         bool
 482
 483 config CHECK_SIGNATURE
 484         bool
 485
 486 config CPUMASK_OFFSTACK
 487         bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
 488         help
 489           Use dynamic allocation for cpumask_var_t, instead of putting
 490           them on the stack.  This is a bit more expensive, but avoids
 491           stack overflow.
 492
 493 config CPU_RMAP
 494         bool
 495         depends on SMP
 496
 497 config DQL
 498         bool
 499
 500 config GLOB
 501         bool
 502 #       This actually supports modular compilation, but the module overhead
 503 #       is ridiculous for the amount of code involved.  Until an out-of-tree
 504 #       driver asks for it, we'll just link it directly it into the kernel
 505 #       when required.  Since we're ignoring out-of-tree users, there's also
 506 #       no need bother prompting for a manual decision:
 507 #       prompt "glob_match() function"
 508         help
 509           This option provides a glob_match function for performing
 510           simple text pattern matching.  It originated in the ATA code
 511           to blacklist particular drive models, but other device drivers
 512           may need similar functionality.
 513
 514           All drivers in the Linux kernel tree that require this function
 515           should automatically select this option.  Say N unless you
 516           are compiling an out-of tree driver which tells you that it
 517           depends on this.
 518
 519 config GLOB_SELFTEST
 520         tristate "glob self-test on init"
 521         depends on GLOB
 522         help
 523           This option enables a simple self-test of the glob_match
 524           function on startup.  It is primarily useful for people
 525           working on the code to ensure they haven't introduced any
 526           regressions.
 527
 528           It only adds a little bit of code and slows kernel boot (or
 529           module load) by a small amount, so you're welcome to play with
 530           it, but you probably don't need it.
 531
 532 #
 533 # Netlink attribute parsing support is select'ed if needed
 534 #
 535 config NLATTR
 536         bool
 537
 538 #
 539 # Generic 64-bit atomic support is selected if needed
 540 #
 541 config GENERIC_ATOMIC64
 542        bool
 543
 544 config LRU_CACHE
 545         tristate
 546
 547 config CLZ_TAB
 548         bool
 549
 550 config IRQ_POLL
 551         bool "IRQ polling library"
 552         help
 553           Helper library to poll interrupt mitigation using polling.
 554
 555 config MPILIB
 556         tristate
 557         select CLZ_TAB
 558         help
 559           Multiprecision maths library from GnuPG.
 560           It is used to implement RSA digital signature verification,
 561           which is used by IMA/EVM digital signature extension.
 562
 563 config SIGNATURE
 564         tristate
 565         depends on KEYS
 566         select CRYPTO
 567         select CRYPTO_SHA1
 568         select MPILIB
 569         help
 570           Digital signature verification. Currently only RSA is supported.
 571           Implementation is done using GnuPG MPI library
 572
 573 config DIMLIB
 574         bool
 575         help
 576           Dynamic Interrupt Moderation library.
 577           Implements an algorithm for dynamically changing CQ moderation values
 578           according to run time performance.
 579
 580 #
 581 # libfdt files, only selected if needed.
 582 #
 583 config LIBFDT
 584         bool
 585
 586 config OID_REGISTRY
 587         tristate
 588         help
 589           Enable fast lookup object identifier registry.
 590
 591 config UCS2_STRING
 592         tristate
 593
 594 #
 595 # generic vdso
 596 #
 597 source "lib/vdso/Kconfig"
 598
 599 source "lib/fonts/Kconfig"
 600
 601 config SG_SPLIT
 602         def_bool n
 603         help
 604          Provides a helper to split scatterlists into chunks, each chunk being
 605          a scatterlist. This should be selected by a driver or an API which
 606          whishes to split a scatterlist amongst multiple DMA channels.
 607
 608 config SG_POOL
 609         def_bool n
 610         help
 611          Provides a helper to allocate chained scatterlists. This should be
 612          selected by a driver or an API which whishes to allocate chained
 613          scatterlist.
 614
 615 #
 616 # sg chaining option
 617 #
 618
 619 config ARCH_NO_SG_CHAIN
 620         def_bool n
 621
 622 config ARCH_HAS_PMEM_API
 623         bool
 624
 625 config MEMREGION
 626         bool
 627
 628 config ARCH_HAS_MEMREMAP_COMPAT_ALIGN
 629         bool
 630
 631 # use memcpy to implement user copies for nommu architectures
 632 config UACCESS_MEMCPY
 633         bool
 634
 635 config ARCH_HAS_UACCESS_FLUSHCACHE
 636         bool
 637
 638 # arch has a concept of a recoverable synchronous exception due to a
 639 # memory-read error like x86 machine-check or ARM data-abort, and
 640 # implements copy_mc_to_{user,kernel} to abort and report
 641 # 'bytes-transferred' if that exception fires when accessing the source
 642 # buffer.
 643 config ARCH_HAS_COPY_MC
 644         bool
 645
 646 # Temporary. Goes away when all archs are cleaned up
 647 config ARCH_STACKWALK
 648        bool
 649
 650 config STACKDEPOT
 651         bool
 652         select STACKTRACE
 653
 654 config SBITMAP
 655         bool
 656
 657 config PARMAN
 658         tristate "parman" if COMPILE_TEST
 659
 660 config OBJAGG
 661         tristate "objagg" if COMPILE_TEST
 662
 663 config STRING_SELFTEST
 664         tristate "Test string functions"
 665
 666 endmenu
 667
 668 config GENERIC_IOREMAP
 669         bool
 670
 671 config GENERIC_LIB_ASHLDI3
 672         bool
 673
 674 config GENERIC_LIB_ASHRDI3
 675         bool
 676
 677 config GENERIC_LIB_LSHRDI3
 678         bool
 679
 680 config GENERIC_LIB_MULDI3
 681         bool
 682
 683 config GENERIC_LIB_CMPDI2
 684         bool
 685
 686 config GENERIC_LIB_UCMPDI2
 687         bool
 688
 689 config GENERIC_LIB_DEVMEM_IS_ALLOWED
 690         bool
 691
 692 config PLDMFW
 693         bool
 694         default n