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