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