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         select BITREVERSE
  28         default n
  29         help
  30           This option provides the packing() helper function, which permits
  31           converting bitfields between a CPU-usable representation and a
  32           memory representation that can have any combination of these quirks:
  33             - Is little endian (bytes are reversed within a 32-bit group)
  34             - The least-significant 32-bit word comes first (within a 64-bit
  35               group)
  36             - The most significant bit of a byte is at its right (bit 0 of a
  37               register description is numerically 2^7).
  38           Drivers may use these helpers to match the bit indices as described
  39           in the data sheets of the peripherals they are in control of.
  40
  41           When in doubt, say N.
  42
  43 config BITREVERSE
  44         tristate
  45
  46 config HAVE_ARCH_BITREVERSE
  47         bool
  48         default n
  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 source "lib/math/Kconfig"
  69
  70 config NO_GENERIC_PCI_IOPORT_MAP
  71         bool
  72
  73 config GENERIC_PCI_IOMAP
  74         bool
  75
  76 config GENERIC_IOMAP
  77         bool
  78         select GENERIC_PCI_IOMAP
  79
  80 config STMP_DEVICE
  81         bool
  82
  83 config ARCH_USE_CMPXCHG_LOCKREF
  84         bool
  85
  86 config ARCH_HAS_FAST_MULTIPLIER
  87         bool
  88
  89 config ARCH_USE_SYM_ANNOTATIONS
  90         bool
  91
  92 config INDIRECT_PIO
  93         bool "Access I/O in non-MMIO mode"
  94         depends on ARM64
  95         depends on HAS_IOPORT
  96         help
  97           On some platforms where no separate I/O space exists, there are I/O
  98           hosts which can not be accessed in MMIO mode. Using the logical PIO
  99           mechanism, the host-local I/O resource can be mapped into system
 100           logic PIO space shared with MMIO hosts, such as PCI/PCIe, then the
 101           system can access the I/O devices with the mapped-logic PIO through
 102           I/O accessors.
 103
 104           This way has relatively little I/O performance cost. Please make
 105           sure your devices really need this configure item enabled.
 106
 107           When in doubt, say N.
 108
 109 config INDIRECT_IOMEM
 110         bool
 111         help
 112           This is selected by other options/architectures to provide the
 113           emulated iomem accessors.
 114
 115 config INDIRECT_IOMEM_FALLBACK
 116         bool
 117         depends on INDIRECT_IOMEM
 118         help
 119           If INDIRECT_IOMEM is selected, this enables falling back to plain
 120           mmio accesses when the IO memory address is not a registered
 121           emulated region.
 122
 123 config TRACE_MMIO_ACCESS
 124         bool "Register read/write tracing"
 125         depends on TRACING && ARCH_HAVE_TRACE_MMIO_ACCESS
 126         help
 127           Create tracepoints for MMIO read/write operations. These trace events
 128           can be used for logging all MMIO read/write operations.
 129
 130 source "lib/crypto/Kconfig"
 131
 132 config CRC_CCITT
 133         tristate "CRC-CCITT functions"
 134         help
 135           This option is provided for the case where no in-kernel-tree
 136           modules require CRC-CCITT functions, but a module built outside
 137           the kernel tree does. Such modules that use library CRC-CCITT
 138           functions require M here.
 139
 140 config CRC16
 141         tristate "CRC16 functions"
 142         help
 143           This option is provided for the case where no in-kernel-tree
 144           modules require CRC16 functions, but a module built outside
 145           the kernel tree does. Such modules that use library CRC16
 146           functions require M here.
 147
 148 config CRC_T10DIF
 149         tristate "CRC calculation for the T10 Data Integrity Field"
 150         select CRYPTO
 151         select CRYPTO_CRCT10DIF
 152         help
 153           This option is only needed if a module that's not in the
 154           kernel tree needs to calculate CRC checks for use with the
 155           SCSI data integrity subsystem.
 156
 157 config CRC64_ROCKSOFT
 158         tristate "CRC calculation for the Rocksoft model CRC64"
 159         select CRC64
 160         select CRYPTO
 161         select CRYPTO_CRC64_ROCKSOFT
 162         help
 163           This option provides a CRC64 API to a registered crypto driver.
 164           This is used with the block layer's data integrity subsystem.
 165
 166 config CRC_ITU_T
 167         tristate "CRC ITU-T V.41 functions"
 168         help
 169           This option is provided for the case where no in-kernel-tree
 170           modules require CRC ITU-T V.41 functions, but a module built outside
 171           the kernel tree does. Such modules that use library CRC ITU-T V.41
 172           functions require M here.
 173
 174 config CRC32
 175         tristate "CRC32/CRC32c functions"
 176         default y
 177         select BITREVERSE
 178         help
 179           This option is provided for the case where no in-kernel-tree
 180           modules require CRC32/CRC32c functions, but a module built outside
 181           the kernel tree does. Such modules that use library CRC32/CRC32c
 182           functions require M here.
 183
 184 config CRC32_SELFTEST
 185         tristate "CRC32 perform self test on init"
 186         depends on CRC32
 187         help
 188           This option enables the CRC32 library functions to perform a
 189           self test on initialization. The self test computes crc32_le
 190           and crc32_be over byte strings with random alignment and length
 191           and computes the total elapsed time and number of bytes processed.
 192
 193 choice
 194         prompt "CRC32 implementation"
 195         depends on CRC32
 196         default CRC32_SLICEBY8
 197         help
 198           This option allows a kernel builder to override the default choice
 199           of CRC32 algorithm.  Choose the default ("slice by 8") unless you
 200           know that you need one of the others.
 201
 202 config CRC32_SLICEBY8
 203         bool "Slice by 8 bytes"
 204         help
 205           Calculate checksum 8 bytes at a time with a clever slicing algorithm.
 206           This is the fastest algorithm, but comes with a 8KiB lookup table.
 207           Most modern processors have enough cache to hold this table without
 208           thrashing the cache.
 209
 210           This is the default implementation choice.  Choose this one unless
 211           you have a good reason not to.
 212
 213 config CRC32_SLICEBY4
 214         bool "Slice by 4 bytes"
 215         help
 216           Calculate checksum 4 bytes at a time with a clever slicing algorithm.
 217           This is a bit slower than slice by 8, but has a smaller 4KiB lookup
 218           table.
 219
 220           Only choose this option if you know what you are doing.
 221
 222 config CRC32_SARWATE
 223         bool "Sarwate's Algorithm (one byte at a time)"
 224         help
 225           Calculate checksum a byte at a time using Sarwate's algorithm.  This
 226           is not particularly fast, but has a small 256 byte lookup table.
 227
 228           Only choose this option if you know what you are doing.
 229
 230 config CRC32_BIT
 231         bool "Classic Algorithm (one bit at a time)"
 232         help
 233           Calculate checksum one bit at a time.  This is VERY slow, but has
 234           no lookup table.  This is provided as a debugging option.
 235
 236           Only choose this option if you are debugging crc32.
 237
 238 endchoice
 239
 240 config CRC64
 241         tristate "CRC64 functions"
 242         help
 243           This option is provided for the case where no in-kernel-tree
 244           modules require CRC64 functions, but a module built outside
 245           the kernel tree does. Such modules that use library CRC64
 246           functions require M here.
 247
 248 config CRC4
 249         tristate "CRC4 functions"
 250         help
 251           This option is provided for the case where no in-kernel-tree
 252           modules require CRC4 functions, but a module built outside
 253           the kernel tree does. Such modules that use library CRC4
 254           functions require M here.
 255
 256 config CRC7
 257         tristate "CRC7 functions"
 258         help
 259           This option is provided for the case where no in-kernel-tree
 260           modules require CRC7 functions, but a module built outside
 261           the kernel tree does. Such modules that use library CRC7
 262           functions require M here.
 263
 264 config LIBCRC32C
 265         tristate "CRC32c (Castagnoli, et al) Cyclic Redundancy-Check"
 266         select CRYPTO
 267         select CRYPTO_CRC32C
 268         help
 269           This option is provided for the case where no in-kernel-tree
 270           modules require CRC32c functions, but a module built outside the
 271           kernel tree does. Such modules that use library CRC32c functions
 272           require M here.  See Castagnoli93.
 273           Module will be libcrc32c.
 274
 275 config CRC8
 276         tristate "CRC8 function"
 277         help
 278           This option provides CRC8 function. Drivers may select this
 279           when they need to do cyclic redundancy check according CRC8
 280           algorithm. Module will be called crc8.
 281
 282 config XXHASH
 283         tristate
 284
 285 config AUDIT_GENERIC
 286         bool
 287         depends on AUDIT && !AUDIT_ARCH
 288         default y
 289
 290 config AUDIT_ARCH_COMPAT_GENERIC
 291         bool
 292         default n
 293
 294 config AUDIT_COMPAT_GENERIC
 295         bool
 296         depends on AUDIT_GENERIC && AUDIT_ARCH_COMPAT_GENERIC && COMPAT
 297         default y
 298
 299 config RANDOM32_SELFTEST
 300         bool "PRNG perform self test on init"
 301         help
 302           This option enables the 32 bit PRNG library functions to perform a
 303           self test on initialization.
 304
 305 #
 306 # compression support is select'ed if needed
 307 #
 308 config 842_COMPRESS
 309         select CRC32
 310         tristate
 311
 312 config 842_DECOMPRESS
 313         select CRC32
 314         tristate
 315
 316 config ZLIB_INFLATE
 317         tristate
 318
 319 config ZLIB_DEFLATE
 320         tristate
 321         select BITREVERSE
 322
 323 config ZLIB_DFLTCC
 324         def_bool y
 325         depends on S390
 326         prompt "Enable s390x DEFLATE CONVERSION CALL support for kernel zlib"
 327         help
 328          Enable s390x hardware support for zlib in the kernel.
 329
 330 config LZO_COMPRESS
 331         tristate
 332
 333 config LZO_DECOMPRESS
 334         tristate
 335
 336 config LZ4_COMPRESS
 337         tristate
 338
 339 config LZ4HC_COMPRESS
 340         tristate
 341
 342 config LZ4_DECOMPRESS
 343         tristate
 344
 345 config ZSTD_COMMON
 346         select XXHASH
 347         tristate
 348
 349 config ZSTD_COMPRESS
 350         select ZSTD_COMMON
 351         tristate
 352
 353 config ZSTD_DECOMPRESS
 354         select ZSTD_COMMON
 355         tristate
 356
 357 source "lib/xz/Kconfig"
 358
 359 #
 360 # These all provide a common interface (hence the apparent duplication with
 361 # ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
 362 #
 363 config DECOMPRESS_GZIP
 364         select ZLIB_INFLATE
 365         tristate
 366
 367 config DECOMPRESS_BZIP2
 368         tristate
 369
 370 config DECOMPRESS_LZMA
 371         tristate
 372
 373 config DECOMPRESS_XZ
 374         select XZ_DEC
 375         tristate
 376
 377 config DECOMPRESS_LZO
 378         select LZO_DECOMPRESS
 379         tristate
 380
 381 config DECOMPRESS_LZ4
 382         select LZ4_DECOMPRESS
 383         tristate
 384
 385 config DECOMPRESS_ZSTD
 386         select ZSTD_DECOMPRESS
 387         tristate
 388
 389 #
 390 # Generic allocator support is selected if needed
 391 #
 392 config GENERIC_ALLOCATOR
 393         bool
 394
 395 #
 396 # reed solomon support is select'ed if needed
 397 #
 398 config REED_SOLOMON
 399         tristate
 400
 401 config REED_SOLOMON_ENC8
 402         bool
 403
 404 config REED_SOLOMON_DEC8
 405         bool
 406
 407 config REED_SOLOMON_ENC16
 408         bool
 409
 410 config REED_SOLOMON_DEC16
 411         bool
 412
 413 #
 414 # BCH support is selected if needed
 415 #
 416 config BCH
 417         tristate
 418         select BITREVERSE
 419
 420 config BCH_CONST_PARAMS
 421         bool
 422         help
 423           Drivers may select this option to force specific constant
 424           values for parameters 'm' (Galois field order) and 't'
 425           (error correction capability). Those specific values must
 426           be set by declaring default values for symbols BCH_CONST_M
 427           and BCH_CONST_T.
 428           Doing so will enable extra compiler optimizations,
 429           improving encoding and decoding performance up to 2x for
 430           usual (m,t) values (typically such that m*t < 200).
 431           When this option is selected, the BCH library supports
 432           only a single (m,t) configuration. This is mainly useful
 433           for NAND flash board drivers requiring known, fixed BCH
 434           parameters.
 435
 436 config BCH_CONST_M
 437         int
 438         range 5 15
 439         help
 440           Constant value for Galois field order 'm'. If 'k' is the
 441           number of data bits to protect, 'm' should be chosen such
 442           that (k + m*t) <= 2**m - 1.
 443           Drivers should declare a default value for this symbol if
 444           they select option BCH_CONST_PARAMS.
 445
 446 config BCH_CONST_T
 447         int
 448         help
 449           Constant value for error correction capability in bits 't'.
 450           Drivers should declare a default value for this symbol if
 451           they select option BCH_CONST_PARAMS.
 452
 453 #
 454 # Textsearch support is select'ed if needed
 455 #
 456 config TEXTSEARCH
 457         bool
 458
 459 config TEXTSEARCH_KMP
 460         tristate
 461
 462 config TEXTSEARCH_BM
 463         tristate
 464
 465 config TEXTSEARCH_FSM
 466         tristate
 467
 468 config BTREE
 469         bool
 470
 471 config INTERVAL_TREE
 472         bool
 473         help
 474           Simple, embeddable, interval-tree. Can find the start of an
 475           overlapping range in log(n) time and then iterate over all
 476           overlapping nodes. The algorithm is implemented as an
 477           augmented rbtree.
 478
 479           See:
 480
 481                 Documentation/core-api/rbtree.rst
 482
 483           for more information.
 484
 485 config INTERVAL_TREE_SPAN_ITER
 486         bool
 487         depends on INTERVAL_TREE
 488
 489 config XARRAY_MULTI
 490         bool
 491         help
 492           Support entries which occupy multiple consecutive indices in the
 493           XArray.
 494
 495 config ASSOCIATIVE_ARRAY
 496         bool
 497         help
 498           Generic associative array.  Can be searched and iterated over whilst
 499           it is being modified.  It is also reasonably quick to search and
 500           modify.  The algorithms are non-recursive, and the trees are highly
 501           capacious.
 502
 503           See:
 504
 505                 Documentation/core-api/assoc_array.rst
 506
 507           for more information.
 508
 509 config CLOSURES
 510         bool
 511
 512 config HAS_IOMEM
 513         bool
 514         depends on !NO_IOMEM
 515         default y
 516
 517 config HAS_IOPORT
 518         bool
 519
 520 config HAS_IOPORT_MAP
 521         bool
 522         depends on HAS_IOMEM && !NO_IOPORT_MAP
 523         default y
 524
 525 source "kernel/dma/Kconfig"
 526
 527 config SGL_ALLOC
 528         bool
 529         default n
 530
 531 config IOMMU_HELPER
 532         bool
 533
 534 config CHECK_SIGNATURE
 535         bool
 536
 537 config CPUMASK_OFFSTACK
 538         bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
 539         help
 540           Use dynamic allocation for cpumask_var_t, instead of putting
 541           them on the stack.  This is a bit more expensive, but avoids
 542           stack overflow.
 543
 544 config FORCE_NR_CPUS
 545        bool "Set number of CPUs at compile time"
 546        depends on SMP && EXPERT && !COMPILE_TEST
 547        help
 548          Say Yes if you have NR_CPUS set to an actual number of possible
 549          CPUs in your system, not to a default value. This forces the core
 550          code to rely on compile-time value and optimize kernel routines
 551          better.
 552
 553 config CPU_RMAP
 554         bool
 555         depends on SMP
 556
 557 config DQL
 558         bool
 559
 560 config GLOB
 561         bool
 562 #       This actually supports modular compilation, but the module overhead
 563 #       is ridiculous for the amount of code involved.  Until an out-of-tree
 564 #       driver asks for it, we'll just link it directly it into the kernel
 565 #       when required.  Since we're ignoring out-of-tree users, there's also
 566 #       no need bother prompting for a manual decision:
 567 #       prompt "glob_match() function"
 568         help
 569           This option provides a glob_match function for performing
 570           simple text pattern matching.  It originated in the ATA code
 571           to blacklist particular drive models, but other device drivers
 572           may need similar functionality.
 573
 574           All drivers in the Linux kernel tree that require this function
 575           should automatically select this option.  Say N unless you
 576           are compiling an out-of tree driver which tells you that it
 577           depends on this.
 578
 579 config GLOB_SELFTEST
 580         tristate "glob self-test on init"
 581         depends on GLOB
 582         help
 583           This option enables a simple self-test of the glob_match
 584           function on startup.  It is primarily useful for people
 585           working on the code to ensure they haven't introduced any
 586           regressions.
 587
 588           It only adds a little bit of code and slows kernel boot (or
 589           module load) by a small amount, so you're welcome to play with
 590           it, but you probably don't need it.
 591
 592 #
 593 # Netlink attribute parsing support is select'ed if needed
 594 #
 595 config NLATTR
 596         bool
 597
 598 #
 599 # Generic 64-bit atomic support is selected if needed
 600 #
 601 config GENERIC_ATOMIC64
 602        bool
 603
 604 config LRU_CACHE
 605         tristate
 606
 607 config CLZ_TAB
 608         bool
 609
 610 config IRQ_POLL
 611         bool "IRQ polling library"
 612         help
 613           Helper library to poll interrupt mitigation using polling.
 614
 615 config MPILIB
 616         tristate
 617         select CLZ_TAB
 618         help
 619           Multiprecision maths library from GnuPG.
 620           It is used to implement RSA digital signature verification,
 621           which is used by IMA/EVM digital signature extension.
 622
 623 config SIGNATURE
 624         tristate
 625         depends on KEYS
 626         select CRYPTO
 627         select CRYPTO_SHA1
 628         select MPILIB
 629         help
 630           Digital signature verification. Currently only RSA is supported.
 631           Implementation is done using GnuPG MPI library
 632
 633 config DIMLIB
 634         bool
 635         help
 636           Dynamic Interrupt Moderation library.
 637           Implements an algorithm for dynamically changing CQ moderation values
 638           according to run time performance.
 639
 640 #
 641 # libfdt files, only selected if needed.
 642 #
 643 config LIBFDT
 644         bool
 645
 646 config OID_REGISTRY
 647         tristate
 648         help
 649           Enable fast lookup object identifier registry.
 650
 651 config UCS2_STRING
 652         tristate
 653
 654 #
 655 # generic vdso
 656 #
 657 source "lib/vdso/Kconfig"
 658
 659 source "lib/fonts/Kconfig"
 660
 661 config SG_SPLIT
 662         def_bool n
 663         help
 664          Provides a helper to split scatterlists into chunks, each chunk being
 665          a scatterlist. This should be selected by a driver or an API which
 666          whishes to split a scatterlist amongst multiple DMA channels.
 667
 668 config SG_POOL
 669         def_bool n
 670         help
 671          Provides a helper to allocate chained scatterlists. This should be
 672          selected by a driver or an API which whishes to allocate chained
 673          scatterlist.
 674
 675 #
 676 # sg chaining option
 677 #
 678
 679 config ARCH_NO_SG_CHAIN
 680         def_bool n
 681
 682 config ARCH_HAS_PMEM_API
 683         bool
 684
 685 config MEMREGION
 686         bool
 687
 688 config ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
 689         bool
 690
 691 config ARCH_HAS_MEMREMAP_COMPAT_ALIGN
 692         bool
 693
 694 # use memcpy to implement user copies for nommu architectures
 695 config UACCESS_MEMCPY
 696         bool
 697
 698 config ARCH_HAS_UACCESS_FLUSHCACHE
 699         bool
 700
 701 # arch has a concept of a recoverable synchronous exception due to a
 702 # memory-read error like x86 machine-check or ARM data-abort, and
 703 # implements copy_mc_to_{user,kernel} to abort and report
 704 # 'bytes-transferred' if that exception fires when accessing the source
 705 # buffer.
 706 config ARCH_HAS_COPY_MC
 707         bool
 708
 709 # Temporary. Goes away when all archs are cleaned up
 710 config ARCH_STACKWALK
 711        bool
 712
 713 config STACKDEPOT
 714         bool
 715         select STACKTRACE
 716         help
 717           Stack depot: stack trace storage that avoids duplication
 718
 719 config STACKDEPOT_ALWAYS_INIT
 720         bool
 721         select STACKDEPOT
 722         help
 723           Always initialize stack depot during early boot
 724
 725 config STACKDEPOT_MAX_FRAMES
 726         int "Maximum number of frames in trace saved in stack depot"
 727         range 1 256
 728         default 64
 729         depends on STACKDEPOT
 730
 731 config REF_TRACKER
 732         bool
 733         depends on STACKTRACE_SUPPORT
 734         select STACKDEPOT
 735
 736 config SBITMAP
 737         bool
 738
 739 config PARMAN
 740         tristate "parman" if COMPILE_TEST
 741
 742 config OBJAGG
 743         tristate "objagg" if COMPILE_TEST
 744
 745 config LWQ_TEST
 746         bool "Boot-time test for lwq queuing"
 747         help
 748           Run boot-time test of light-weight queuing.
 749
 750 endmenu
 751
 752 config GENERIC_IOREMAP
 753         bool
 754
 755 config GENERIC_LIB_ASHLDI3
 756         bool
 757
 758 config GENERIC_LIB_ASHRDI3
 759         bool
 760
 761 config GENERIC_LIB_LSHRDI3
 762         bool
 763
 764 config GENERIC_LIB_MULDI3
 765         bool
 766
 767 config GENERIC_LIB_CMPDI2
 768         bool
 769
 770 config GENERIC_LIB_UCMPDI2
 771         bool
 772
 773 config GENERIC_LIB_DEVMEM_IS_ALLOWED
 774         bool
 775
 776 config PLDMFW
 777         bool
 778         default n
 779
 780 config ASN1_ENCODER
 781        tristate
 782
 783 config POLYNOMIAL
 784        tristate
 785
 786 config FIRMWARE_TABLE
 787         bool