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