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