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         help
  49           This option enables the use of hardware bit-reversal instructions on
  50           architectures which support such operations.
  51
  52 config ARCH_HAS_STRNCPY_FROM_USER
  53         bool
  54
  55 config ARCH_HAS_STRNLEN_USER
  56         bool
  57
  58 config GENERIC_STRNCPY_FROM_USER
  59         def_bool !ARCH_HAS_STRNCPY_FROM_USER
  60
  61 config GENERIC_STRNLEN_USER
  62         def_bool !ARCH_HAS_STRNLEN_USER
  63
  64 config GENERIC_NET_UTILS
  65         bool
  66
  67 source "lib/math/Kconfig"
  68
  69 config NO_GENERIC_PCI_IOPORT_MAP
  70         bool
  71
  72 config GENERIC_PCI_IOMAP
  73         bool
  74
  75 config GENERIC_IOMAP
  76         bool
  77         select GENERIC_PCI_IOMAP
  78
  79 config STMP_DEVICE
  80         bool
  81
  82 config ARCH_USE_CMPXCHG_LOCKREF
  83         bool
  84
  85 config ARCH_HAS_FAST_MULTIPLIER
  86         bool
  87
  88 config ARCH_USE_SYM_ANNOTATIONS
  89         bool
  90
  91 config INDIRECT_PIO
  92         bool "Access I/O in non-MMIO mode"
  93         depends on ARM64
  94         help
  95           On some platforms where no separate I/O space exists, there are I/O
  96           hosts which can not be accessed in MMIO mode. Using the logical PIO
  97           mechanism, the host-local I/O resource can be mapped into system
  98           logic PIO space shared with MMIO hosts, such as PCI/PCIe, then the
  99           system can access the I/O devices with the mapped-logic PIO through
 100           I/O accessors.
 101
 102           This way has relatively little I/O performance cost. Please make
 103           sure your devices really need this configure item enabled.
 104
 105           When in doubt, say N.
 106
 107 config INDIRECT_IOMEM
 108         bool
 109         help
 110           This is selected by other options/architectures to provide the
 111           emulated iomem accessors.
 112
 113 config INDIRECT_IOMEM_FALLBACK
 114         bool
 115         depends on INDIRECT_IOMEM
 116         help
 117           If INDIRECT_IOMEM is selected, this enables falling back to plain
 118           mmio accesses when the IO memory address is not a registered
 119           emulated region.
 120
 121 source "lib/crypto/Kconfig"
 122
 123 config LIB_MEMNEQ
 124         bool
 125
 126 config CRC_CCITT
 127         tristate "CRC-CCITT functions"
 128         help
 129           This option is provided for the case where no in-kernel-tree
 130           modules require CRC-CCITT functions, but a module built outside
 131           the kernel tree does. Such modules that use library CRC-CCITT
 132           functions require M here.
 133
 134 config CRC16
 135         tristate "CRC16 functions"
 136         help
 137           This option is provided for the case where no in-kernel-tree
 138           modules require CRC16 functions, but a module built outside
 139           the kernel tree does. Such modules that use library CRC16
 140           functions require M here.
 141
 142 config CRC_T10DIF
 143         tristate "CRC calculation for the T10 Data Integrity Field"
 144         select CRYPTO
 145         select CRYPTO_CRCT10DIF
 146         help
 147           This option is only needed if a module that's not in the
 148           kernel tree needs to calculate CRC checks for use with the
 149           SCSI data integrity subsystem.
 150
 151 config CRC64_ROCKSOFT
 152         tristate "CRC calculation for the Rocksoft model CRC64"
 153         select CRC64
 154         select CRYPTO
 155         select CRYPTO_CRC64_ROCKSOFT
 156         help
 157           This option provides a CRC64 API to a registered crypto driver.
 158           This is used with the block layer's data integrity subsystem.
 159
 160 config CRC_ITU_T
 161         tristate "CRC ITU-T V.41 functions"
 162         help
 163           This option is provided for the case where no in-kernel-tree
 164           modules require CRC ITU-T V.41 functions, but a module built outside
 165           the kernel tree does. Such modules that use library CRC ITU-T V.41
 166           functions require M here.
 167
 168 config CRC32
 169         tristate "CRC32/CRC32c functions"
 170         default y
 171         select BITREVERSE
 172         help
 173           This option is provided for the case where no in-kernel-tree
 174           modules require CRC32/CRC32c functions, but a module built outside
 175           the kernel tree does. Such modules that use library CRC32/CRC32c
 176           functions require M here.
 177
 178 config CRC32_SELFTEST
 179         tristate "CRC32 perform self test on init"
 180         depends on CRC32
 181         help
 182           This option enables the CRC32 library functions to perform a
 183           self test on initialization. The self test computes crc32_le
 184           and crc32_be over byte strings with random alignment and length
 185           and computes the total elapsed time and number of bytes processed.
 186
 187 choice
 188         prompt "CRC32 implementation"
 189         depends on CRC32
 190         default CRC32_SLICEBY8
 191         help
 192           This option allows a kernel builder to override the default choice
 193           of CRC32 algorithm.  Choose the default ("slice by 8") unless you
 194           know that you need one of the others.
 195
 196 config CRC32_SLICEBY8
 197         bool "Slice by 8 bytes"
 198         help
 199           Calculate checksum 8 bytes at a time with a clever slicing algorithm.
 200           This is the fastest algorithm, but comes with a 8KiB lookup table.
 201           Most modern processors have enough cache to hold this table without
 202           thrashing the cache.
 203
 204           This is the default implementation choice.  Choose this one unless
 205           you have a good reason not to.
 206
 207 config CRC32_SLICEBY4
 208         bool "Slice by 4 bytes"
 209         help
 210           Calculate checksum 4 bytes at a time with a clever slicing algorithm.
 211           This is a bit slower than slice by 8, but has a smaller 4KiB lookup
 212           table.
 213
 214           Only choose this option if you know what you are doing.
 215
 216 config CRC32_SARWATE
 217         bool "Sarwate's Algorithm (one byte at a time)"
 218         help
 219           Calculate checksum a byte at a time using Sarwate's algorithm.  This
 220           is not particularly fast, but has a small 256 byte lookup table.
 221
 222           Only choose this option if you know what you are doing.
 223
 224 config CRC32_BIT
 225         bool "Classic Algorithm (one bit at a time)"
 226         help
 227           Calculate checksum one bit at a time.  This is VERY slow, but has
 228           no lookup table.  This is provided as a debugging option.
 229
 230           Only choose this option if you are debugging crc32.
 231
 232 endchoice
 233
 234 config CRC64
 235         tristate "CRC64 functions"
 236         help
 237           This option is provided for the case where no in-kernel-tree
 238           modules require CRC64 functions, but a module built outside
 239           the kernel tree does. Such modules that use library CRC64
 240           functions require M here.
 241
 242 config CRC4
 243         tristate "CRC4 functions"
 244         help
 245           This option is provided for the case where no in-kernel-tree
 246           modules require CRC4 functions, but a module built outside
 247           the kernel tree does. Such modules that use library CRC4
 248           functions require M here.
 249
 250 config CRC7
 251         tristate "CRC7 functions"
 252         help
 253           This option is provided for the case where no in-kernel-tree
 254           modules require CRC7 functions, but a module built outside
 255           the kernel tree does. Such modules that use library CRC7
 256           functions require M here.
 257
 258 config LIBCRC32C
 259         tristate "CRC32c (Castagnoli, et al) Cyclic Redundancy-Check"
 260         select CRYPTO
 261         select CRYPTO_CRC32C
 262         help
 263           This option is provided for the case where no in-kernel-tree
 264           modules require CRC32c functions, but a module built outside the
 265           kernel tree does. Such modules that use library CRC32c functions
 266           require M here.  See Castagnoli93.
 267           Module will be libcrc32c.
 268
 269 config CRC8
 270         tristate "CRC8 function"
 271         help
 272           This option provides CRC8 function. Drivers may select this
 273           when they need to do cyclic redundancy check according CRC8
 274           algorithm. Module will be called crc8.
 275
 276 config XXHASH
 277         tristate
 278
 279 config AUDIT_GENERIC
 280         bool
 281         depends on AUDIT && !AUDIT_ARCH
 282         default y
 283
 284 config AUDIT_ARCH_COMPAT_GENERIC
 285         bool
 286         default n
 287
 288 config AUDIT_COMPAT_GENERIC
 289         bool
 290         depends on AUDIT_GENERIC && AUDIT_ARCH_COMPAT_GENERIC && COMPAT
 291         default y
 292
 293 config RANDOM32_SELFTEST
 294         bool "PRNG perform self test on init"
 295         help
 296           This option enables the 32 bit PRNG library functions to perform a
 297           self test on initialization.
 298
 299 #
 300 # compression support is select'ed if needed
 301 #
 302 config 842_COMPRESS
 303         select CRC32
 304         tristate
 305
 306 config 842_DECOMPRESS
 307         select CRC32
 308         tristate
 309
 310 config ZLIB_INFLATE
 311         tristate
 312
 313 config ZLIB_DEFLATE
 314         tristate
 315         select BITREVERSE
 316
 317 config ZLIB_DFLTCC
 318         def_bool y
 319         depends on S390
 320         prompt "Enable s390x DEFLATE CONVERSION CALL support for kernel zlib"
 321         help
 322          Enable s390x hardware support for zlib in the kernel.
 323
 324 config LZO_COMPRESS
 325         tristate
 326
 327 config LZO_DECOMPRESS
 328         tristate
 329
 330 config LZ4_COMPRESS
 331         tristate
 332
 333 config LZ4HC_COMPRESS
 334         tristate
 335
 336 config LZ4_DECOMPRESS
 337         tristate
 338
 339 config ZSTD_COMPRESS
 340         select XXHASH
 341         tristate
 342
 343 config ZSTD_DECOMPRESS
 344         select XXHASH
 345         tristate
 346
 347 source "lib/xz/Kconfig"
 348
 349 #
 350 # These all provide a common interface (hence the apparent duplication with
 351 # ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
 352 #
 353 config DECOMPRESS_GZIP
 354         select ZLIB_INFLATE
 355         tristate
 356
 357 config DECOMPRESS_BZIP2
 358         tristate
 359
 360 config DECOMPRESS_LZMA
 361         tristate
 362
 363 config DECOMPRESS_XZ
 364         select XZ_DEC
 365         tristate
 366
 367 config DECOMPRESS_LZO
 368         select LZO_DECOMPRESS
 369         tristate
 370
 371 config DECOMPRESS_LZ4
 372         select LZ4_DECOMPRESS
 373         tristate
 374
 375 config DECOMPRESS_ZSTD
 376         select ZSTD_DECOMPRESS
 377         tristate
 378
 379 #
 380 # Generic allocator support is selected if needed
 381 #
 382 config GENERIC_ALLOCATOR
 383         bool
 384
 385 #
 386 # reed solomon support is select'ed if needed
 387 #
 388 config REED_SOLOMON
 389         tristate
 390
 391 config REED_SOLOMON_ENC8
 392         bool
 393
 394 config REED_SOLOMON_DEC8
 395         bool
 396
 397 config REED_SOLOMON_ENC16
 398         bool
 399
 400 config REED_SOLOMON_DEC16
 401         bool
 402
 403 #
 404 # BCH support is selected if needed
 405 #
 406 config BCH
 407         tristate
 408
 409 config BCH_CONST_PARAMS
 410         bool
 411         help
 412           Drivers may select this option to force specific constant
 413           values for parameters 'm' (Galois field order) and 't'
 414           (error correction capability). Those specific values must
 415           be set by declaring default values for symbols BCH_CONST_M
 416           and BCH_CONST_T.
 417           Doing so will enable extra compiler optimizations,
 418           improving encoding and decoding performance up to 2x for
 419           usual (m,t) values (typically such that m*t < 200).
 420           When this option is selected, the BCH library supports
 421           only a single (m,t) configuration. This is mainly useful
 422           for NAND flash board drivers requiring known, fixed BCH
 423           parameters.
 424
 425 config BCH_CONST_M
 426         int
 427         range 5 15
 428         help
 429           Constant value for Galois field order 'm'. If 'k' is the
 430           number of data bits to protect, 'm' should be chosen such
 431           that (k + m*t) <= 2**m - 1.
 432           Drivers should declare a default value for this symbol if
 433           they select option BCH_CONST_PARAMS.
 434
 435 config BCH_CONST_T
 436         int
 437         help
 438           Constant value for error correction capability in bits 't'.
 439           Drivers should declare a default value for this symbol if
 440           they select option BCH_CONST_PARAMS.
 441
 442 #
 443 # Textsearch support is select'ed if needed
 444 #
 445 config TEXTSEARCH
 446         bool
 447
 448 config TEXTSEARCH_KMP
 449         tristate
 450
 451 config TEXTSEARCH_BM
 452         tristate
 453
 454 config TEXTSEARCH_FSM
 455         tristate
 456
 457 config BTREE
 458         bool
 459
 460 config INTERVAL_TREE
 461         bool
 462         help
 463           Simple, embeddable, interval-tree. Can find the start of an
 464           overlapping range in log(n) time and then iterate over all
 465           overlapping nodes. The algorithm is implemented as an
 466           augmented rbtree.
 467
 468           See:
 469
 470                 Documentation/core-api/rbtree.rst
 471
 472           for more information.
 473
 474 config XARRAY_MULTI
 475         bool
 476         help
 477           Support entries which occupy multiple consecutive indices in the
 478           XArray.
 479
 480 config ASSOCIATIVE_ARRAY
 481         bool
 482         help
 483           Generic associative array.  Can be searched and iterated over whilst
 484           it is being modified.  It is also reasonably quick to search and
 485           modify.  The algorithms are non-recursive, and the trees are highly
 486           capacious.
 487
 488           See:
 489
 490                 Documentation/core-api/assoc_array.rst
 491
 492           for more information.
 493
 494 config HAS_IOMEM
 495         bool
 496         depends on !NO_IOMEM
 497         default y
 498
 499 config HAS_IOPORT_MAP
 500         bool
 501         depends on HAS_IOMEM && !NO_IOPORT_MAP
 502         default y
 503
 504 source "kernel/dma/Kconfig"
 505
 506 config SGL_ALLOC
 507         bool
 508         default n
 509
 510 config IOMMU_HELPER
 511         bool
 512
 513 config CHECK_SIGNATURE
 514         bool
 515
 516 config CPUMASK_OFFSTACK
 517         bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
 518         help
 519           Use dynamic allocation for cpumask_var_t, instead of putting
 520           them on the stack.  This is a bit more expensive, but avoids
 521           stack overflow.
 522
 523 config CPU_RMAP
 524         bool
 525         depends on SMP
 526
 527 config DQL
 528         bool
 529
 530 config GLOB
 531         bool
 532 #       This actually supports modular compilation, but the module overhead
 533 #       is ridiculous for the amount of code involved.  Until an out-of-tree
 534 #       driver asks for it, we'll just link it directly it into the kernel
 535 #       when required.  Since we're ignoring out-of-tree users, there's also
 536 #       no need bother prompting for a manual decision:
 537 #       prompt "glob_match() function"
 538         help
 539           This option provides a glob_match function for performing
 540           simple text pattern matching.  It originated in the ATA code
 541           to blacklist particular drive models, but other device drivers
 542           may need similar functionality.
 543
 544           All drivers in the Linux kernel tree that require this function
 545           should automatically select this option.  Say N unless you
 546           are compiling an out-of tree driver which tells you that it
 547           depends on this.
 548
 549 config GLOB_SELFTEST
 550         tristate "glob self-test on init"
 551         depends on GLOB
 552         help
 553           This option enables a simple self-test of the glob_match
 554           function on startup.  It is primarily useful for people
 555           working on the code to ensure they haven't introduced any
 556           regressions.
 557
 558           It only adds a little bit of code and slows kernel boot (or
 559           module load) by a small amount, so you're welcome to play with
 560           it, but you probably don't need it.
 561
 562 #
 563 # Netlink attribute parsing support is select'ed if needed
 564 #
 565 config NLATTR
 566         bool
 567
 568 #
 569 # Generic 64-bit atomic support is selected if needed
 570 #
 571 config GENERIC_ATOMIC64
 572        bool
 573
 574 config LRU_CACHE
 575         tristate
 576
 577 config CLZ_TAB
 578         bool
 579
 580 config IRQ_POLL
 581         bool "IRQ polling library"
 582         help
 583           Helper library to poll interrupt mitigation using polling.
 584
 585 config MPILIB
 586         tristate
 587         select CLZ_TAB
 588         help
 589           Multiprecision maths library from GnuPG.
 590           It is used to implement RSA digital signature verification,
 591           which is used by IMA/EVM digital signature extension.
 592
 593 config SIGNATURE
 594         tristate
 595         depends on KEYS
 596         select CRYPTO
 597         select CRYPTO_SHA1
 598         select MPILIB
 599         help
 600           Digital signature verification. Currently only RSA is supported.
 601           Implementation is done using GnuPG MPI library
 602
 603 config DIMLIB
 604         bool
 605         help
 606           Dynamic Interrupt Moderation library.
 607           Implements an algorithm for dynamically changing CQ moderation values
 608           according to run time performance.
 609
 610 #
 611 # libfdt files, only selected if needed.
 612 #
 613 config LIBFDT
 614         bool
 615
 616 config OID_REGISTRY
 617         tristate
 618         help
 619           Enable fast lookup object identifier registry.
 620
 621 config UCS2_STRING
 622         tristate
 623
 624 #
 625 # generic vdso
 626 #
 627 source "lib/vdso/Kconfig"
 628
 629 source "lib/fonts/Kconfig"
 630
 631 config SG_SPLIT
 632         def_bool n
 633         help
 634          Provides a helper to split scatterlists into chunks, each chunk being
 635          a scatterlist. This should be selected by a driver or an API which
 636          whishes to split a scatterlist amongst multiple DMA channels.
 637
 638 config SG_POOL
 639         def_bool n
 640         help
 641          Provides a helper to allocate chained scatterlists. This should be
 642          selected by a driver or an API which whishes to allocate chained
 643          scatterlist.
 644
 645 #
 646 # sg chaining option
 647 #
 648
 649 config ARCH_NO_SG_CHAIN
 650         def_bool n
 651
 652 config ARCH_HAS_PMEM_API
 653         bool
 654
 655 config MEMREGION
 656         bool
 657
 658 config ARCH_HAS_MEMREMAP_COMPAT_ALIGN
 659         bool
 660
 661 # use memcpy to implement user copies for nommu architectures
 662 config UACCESS_MEMCPY
 663         bool
 664
 665 config ARCH_HAS_UACCESS_FLUSHCACHE
 666         bool
 667
 668 # arch has a concept of a recoverable synchronous exception due to a
 669 # memory-read error like x86 machine-check or ARM data-abort, and
 670 # implements copy_mc_to_{user,kernel} to abort and report
 671 # 'bytes-transferred' if that exception fires when accessing the source
 672 # buffer.
 673 config ARCH_HAS_COPY_MC
 674         bool
 675
 676 # Temporary. Goes away when all archs are cleaned up
 677 config ARCH_STACKWALK
 678        bool
 679
 680 config STACKDEPOT
 681         bool
 682         select STACKTRACE
 683
 684 config STACKDEPOT_ALWAYS_INIT
 685         bool
 686         select STACKDEPOT
 687
 688 config STACK_HASH_ORDER
 689         int "stack depot hash size (12 => 4KB, 20 => 1024KB)"
 690         range 12 20
 691         default 20
 692         depends on STACKDEPOT
 693         help
 694          Select the hash size as a power of 2 for the stackdepot hash table.
 695          Choose a lower value to reduce the memory impact.
 696
 697 config REF_TRACKER
 698         bool
 699         depends on STACKTRACE_SUPPORT
 700         select STACKDEPOT
 701
 702 config SBITMAP
 703         bool
 704
 705 config PARMAN
 706         tristate "parman" if COMPILE_TEST
 707
 708 config OBJAGG
 709         tristate "objagg" if COMPILE_TEST
 710
 711 endmenu
 712
 713 config GENERIC_IOREMAP
 714         bool
 715
 716 config GENERIC_LIB_ASHLDI3
 717         bool
 718
 719 config GENERIC_LIB_ASHRDI3
 720         bool
 721
 722 config GENERIC_LIB_LSHRDI3
 723         bool
 724
 725 config GENERIC_LIB_MULDI3
 726         bool
 727
 728 config GENERIC_LIB_CMPDI2
 729         bool
 730
 731 config GENERIC_LIB_UCMPDI2
 732         bool
 733
 734 config GENERIC_LIB_DEVMEM_IS_ALLOWED
 735         bool
 736
 737 config PLDMFW
 738         bool
 739         default n
 740
 741 config ASN1_ENCODER
 742        tristate
 743
 744 config POLYNOMIAL
 745        tristate