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