2 # Library configuration
8 menu "Library routines"
16 config HAVE_ARCH_BITREVERSE
21 This option enables the use of hardware bit-reversal instructions on
22 architectures which support such operations.
27 config GENERIC_STRNCPY_FROM_USER
30 config GENERIC_STRNLEN_USER
33 config GENERIC_NET_UTILS
36 config GENERIC_FIND_FIRST_BIT
39 config NO_GENERIC_PCI_IOPORT_MAP
42 config GENERIC_PCI_IOMAP
47 select GENERIC_PCI_IOMAP
52 config ARCH_USE_CMPXCHG_LOCKREF
55 config ARCH_HAS_FAST_MULTIPLIER
59 tristate "CRC-CCITT functions"
61 This option is provided for the case where no in-kernel-tree
62 modules require CRC-CCITT functions, but a module built outside
63 the kernel tree does. Such modules that use library CRC-CCITT
64 functions require M here.
67 tristate "CRC16 functions"
69 This option is provided for the case where no in-kernel-tree
70 modules require CRC16 functions, but a module built outside
71 the kernel tree does. Such modules that use library CRC16
72 functions require M here.
75 tristate "CRC calculation for the T10 Data Integrity Field"
77 select CRYPTO_CRCT10DIF
79 This option is only needed if a module that's not in the
80 kernel tree needs to calculate CRC checks for use with the
81 SCSI data integrity subsystem.
84 tristate "CRC ITU-T V.41 functions"
86 This option is provided for the case where no in-kernel-tree
87 modules require CRC ITU-T V.41 functions, but a module built outside
88 the kernel tree does. Such modules that use library CRC ITU-T V.41
89 functions require M here.
92 tristate "CRC32/CRC32c functions"
96 This option is provided for the case where no in-kernel-tree
97 modules require CRC32/CRC32c functions, but a module built outside
98 the kernel tree does. Such modules that use library CRC32/CRC32c
99 functions require M here.
101 config CRC32_SELFTEST
102 tristate "CRC32 perform self test on init"
105 This option enables the CRC32 library functions to perform a
106 self test on initialization. The self test computes crc32_le
107 and crc32_be over byte strings with random alignment and length
108 and computes the total elapsed time and number of bytes processed.
111 prompt "CRC32 implementation"
113 default CRC32_SLICEBY8
115 This option allows a kernel builder to override the default choice
116 of CRC32 algorithm. Choose the default ("slice by 8") unless you
117 know that you need one of the others.
119 config CRC32_SLICEBY8
120 bool "Slice by 8 bytes"
122 Calculate checksum 8 bytes at a time with a clever slicing algorithm.
123 This is the fastest algorithm, but comes with a 8KiB lookup table.
124 Most modern processors have enough cache to hold this table without
127 This is the default implementation choice. Choose this one unless
128 you have a good reason not to.
130 config CRC32_SLICEBY4
131 bool "Slice by 4 bytes"
133 Calculate checksum 4 bytes at a time with a clever slicing algorithm.
134 This is a bit slower than slice by 8, but has a smaller 4KiB lookup
137 Only choose this option if you know what you are doing.
140 bool "Sarwate's Algorithm (one byte at a time)"
142 Calculate checksum a byte at a time using Sarwate's algorithm. This
143 is not particularly fast, but has a small 256 byte lookup table.
145 Only choose this option if you know what you are doing.
148 bool "Classic Algorithm (one bit at a time)"
150 Calculate checksum one bit at a time. This is VERY slow, but has
151 no lookup table. This is provided as a debugging option.
153 Only choose this option if you are debugging crc32.
158 tristate "CRC4 functions"
160 This option is provided for the case where no in-kernel-tree
161 modules require CRC4 functions, but a module built outside
162 the kernel tree does. Such modules that use library CRC4
163 functions require M here.
166 tristate "CRC7 functions"
168 This option is provided for the case where no in-kernel-tree
169 modules require CRC7 functions, but a module built outside
170 the kernel tree does. Such modules that use library CRC7
171 functions require M here.
174 tristate "CRC32c (Castagnoli, et al) Cyclic Redundancy-Check"
178 This option is provided for the case where no in-kernel-tree
179 modules require CRC32c functions, but a module built outside the
180 kernel tree does. Such modules that use library CRC32c functions
181 require M here. See Castagnoli93.
182 Module will be libcrc32c.
185 tristate "CRC8 function"
187 This option provides CRC8 function. Drivers may select this
188 when they need to do cyclic redundancy check according CRC8
189 algorithm. Module will be called crc8.
196 depends on AUDIT && !AUDIT_ARCH
199 config AUDIT_ARCH_COMPAT_GENERIC
203 config AUDIT_COMPAT_GENERIC
205 depends on AUDIT_GENERIC && AUDIT_ARCH_COMPAT_GENERIC && COMPAT
208 config RANDOM32_SELFTEST
209 bool "PRNG perform self test on init"
212 This option enables the 32 bit PRNG library functions to perform a
213 self test on initialization.
216 # compression support is select'ed if needed
222 config 842_DECOMPRESS
236 config LZO_DECOMPRESS
242 config LZ4HC_COMPRESS
245 config LZ4_DECOMPRESS
252 config ZSTD_DECOMPRESS
256 source "lib/xz/Kconfig"
259 # These all provide a common interface (hence the apparent duplication with
260 # ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
262 config DECOMPRESS_GZIP
266 config DECOMPRESS_BZIP2
269 config DECOMPRESS_LZMA
276 config DECOMPRESS_LZO
277 select LZO_DECOMPRESS
280 config DECOMPRESS_LZ4
281 select LZ4_DECOMPRESS
285 # Generic allocator support is selected if needed
287 config GENERIC_ALLOCATOR
291 # reed solomon support is select'ed if needed
296 config REED_SOLOMON_ENC8
299 config REED_SOLOMON_DEC8
302 config REED_SOLOMON_ENC16
305 config REED_SOLOMON_DEC16
309 # BCH support is selected if needed
314 config BCH_CONST_PARAMS
317 Drivers may select this option to force specific constant
318 values for parameters 'm' (Galois field order) and 't'
319 (error correction capability). Those specific values must
320 be set by declaring default values for symbols BCH_CONST_M
322 Doing so will enable extra compiler optimizations,
323 improving encoding and decoding performance up to 2x for
324 usual (m,t) values (typically such that m*t < 200).
325 When this option is selected, the BCH library supports
326 only a single (m,t) configuration. This is mainly useful
327 for NAND flash board drivers requiring known, fixed BCH
334 Constant value for Galois field order 'm'. If 'k' is the
335 number of data bits to protect, 'm' should be chosen such
336 that (k + m*t) <= 2**m - 1.
337 Drivers should declare a default value for this symbol if
338 they select option BCH_CONST_PARAMS.
343 Constant value for error correction capability in bits 't'.
344 Drivers should declare a default value for this symbol if
345 they select option BCH_CONST_PARAMS.
348 # Textsearch support is select'ed if needed
353 config TEXTSEARCH_KMP
359 config TEXTSEARCH_FSM
368 Simple, embeddable, interval-tree. Can find the start of an
369 overlapping range in log(n) time and then iterate over all
370 overlapping nodes. The algorithm is implemented as an
375 Documentation/rbtree.txt
377 for more information.
379 config RADIX_TREE_MULTIORDER
382 config ASSOCIATIVE_ARRAY
385 Generic associative array. Can be searched and iterated over whilst
386 it is being modified. It is also reasonably quick to search and
387 modify. The algorithms are non-recursive, and the trees are highly
392 Documentation/assoc_array.txt
394 for more information.
402 config HAS_IOPORT_MAP
404 depends on HAS_IOMEM && !NO_IOPORT_MAP
416 config DMA_DIRECT_OPS
418 depends on HAS_DMA && (!64BIT || ARCH_DMA_ADDR_T_64BIT)
423 depends on HAS_DMA && (!64BIT || ARCH_DMA_ADDR_T_64BIT)
426 config CHECK_SIGNATURE
429 config CPUMASK_OFFSTACK
430 bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
432 Use dynamic allocation for cpumask_var_t, instead of putting
433 them on the stack. This is a bit more expensive, but avoids
445 # This actually supports modular compilation, but the module overhead
446 # is ridiculous for the amount of code involved. Until an out-of-tree
447 # driver asks for it, we'll just link it directly it into the kernel
448 # when required. Since we're ignoring out-of-tree users, there's also
449 # no need bother prompting for a manual decision:
450 # prompt "glob_match() function"
452 This option provides a glob_match function for performing
453 simple text pattern matching. It originated in the ATA code
454 to blacklist particular drive models, but other device drivers
455 may need similar functionality.
457 All drivers in the Linux kernel tree that require this function
458 should automatically select this option. Say N unless you
459 are compiling an out-of tree driver which tells you that it
463 tristate "glob self-test on init"
466 This option enables a simple self-test of the glob_match
467 function on startup. It is primarily useful for people
468 working on the code to ensure they haven't introduced any
471 It only adds a little bit of code and slows kernel boot (or
472 module load) by a small amount, so you're welcome to play with
473 it, but you probably don't need it.
476 # Netlink attribute parsing support is select'ed if needed
482 # Generic 64-bit atomic support is selected if needed
484 config GENERIC_ATOMIC64
494 tristate "CORDIC algorithm"
496 This option provides an implementation of the CORDIC algorithm;
497 calculations are in fixed point. Module will be called cordic.
500 bool "JEDEC DDR data"
502 Data from JEDEC specs for DDR SDRAM memories,
503 particularly the AC timing parameters and addressing
504 information. This data is useful for drivers handling
505 DDR SDRAM controllers.
508 bool "IRQ polling library"
510 Helper library to poll interrupt mitigation using polling.
516 Multiprecision maths library from GnuPG.
517 It is used to implement RSA digital signature verification,
518 which is used by IMA/EVM digital signature extension.
527 Digital signature verification. Currently only RSA is supported.
528 Implementation is done using GnuPG MPI library
531 # libfdt files, only selected if needed.
539 Enable fast lookup object identifier registry.
544 source "lib/fonts/Kconfig"
549 Provides a helper to split scatterlists into chunks, each chunk being
550 a scatterlist. This should be selected by a driver or an API which
551 whishes to split a scatterlist amongst multiple DMA channels.
556 Provides a helper to allocate chained scatterlists. This should be
557 selected by a driver or an API which whishes to allocate chained
564 config ARCH_HAS_SG_CHAIN
567 config ARCH_HAS_PMEM_API
570 config ARCH_HAS_UACCESS_FLUSHCACHE
581 tristate "parman" if COMPILE_TEST
586 config STRING_SELFTEST
587 tristate "Test string functions"
591 config GENERIC_ASHLDI3
594 config GENERIC_ASHRDI3
597 config GENERIC_LSHRDI3
600 config GENERIC_MULDI3
603 config GENERIC_CMPDI2
606 config GENERIC_UCMPDI2