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
56 config ARCH_USE_CMPXCHG_LOCKREF
59 config ARCH_HAS_FAST_MULTIPLIER
63 tristate "CRC-CCITT functions"
65 This option is provided for the case where no in-kernel-tree
66 modules require CRC-CCITT functions, but a module built outside
67 the kernel tree does. Such modules that use library CRC-CCITT
68 functions require M here.
71 tristate "CRC16 functions"
73 This option is provided for the case where no in-kernel-tree
74 modules require CRC16 functions, but a module built outside
75 the kernel tree does. Such modules that use library CRC16
76 functions require M here.
79 tristate "CRC calculation for the T10 Data Integrity Field"
81 select CRYPTO_CRCT10DIF
83 This option is only needed if a module that's not in the
84 kernel tree needs to calculate CRC checks for use with the
85 SCSI data integrity subsystem.
88 tristate "CRC ITU-T V.41 functions"
90 This option is provided for the case where no in-kernel-tree
91 modules require CRC ITU-T V.41 functions, but a module built outside
92 the kernel tree does. Such modules that use library CRC ITU-T V.41
93 functions require M here.
96 tristate "CRC32/CRC32c functions"
100 This option is provided for the case where no in-kernel-tree
101 modules require CRC32/CRC32c functions, but a module built outside
102 the kernel tree does. Such modules that use library CRC32/CRC32c
103 functions require M here.
105 config CRC32_SELFTEST
106 tristate "CRC32 perform self test on init"
109 This option enables the CRC32 library functions to perform a
110 self test on initialization. The self test computes crc32_le
111 and crc32_be over byte strings with random alignment and length
112 and computes the total elapsed time and number of bytes processed.
115 prompt "CRC32 implementation"
117 default CRC32_SLICEBY8
119 This option allows a kernel builder to override the default choice
120 of CRC32 algorithm. Choose the default ("slice by 8") unless you
121 know that you need one of the others.
123 config CRC32_SLICEBY8
124 bool "Slice by 8 bytes"
126 Calculate checksum 8 bytes at a time with a clever slicing algorithm.
127 This is the fastest algorithm, but comes with a 8KiB lookup table.
128 Most modern processors have enough cache to hold this table without
131 This is the default implementation choice. Choose this one unless
132 you have a good reason not to.
134 config CRC32_SLICEBY4
135 bool "Slice by 4 bytes"
137 Calculate checksum 4 bytes at a time with a clever slicing algorithm.
138 This is a bit slower than slice by 8, but has a smaller 4KiB lookup
141 Only choose this option if you know what you are doing.
144 bool "Sarwate's Algorithm (one byte at a time)"
146 Calculate checksum a byte at a time using Sarwate's algorithm. This
147 is not particularly fast, but has a small 256 byte lookup table.
149 Only choose this option if you know what you are doing.
152 bool "Classic Algorithm (one bit at a time)"
154 Calculate checksum one bit at a time. This is VERY slow, but has
155 no lookup table. This is provided as a debugging option.
157 Only choose this option if you are debugging crc32.
162 tristate "CRC4 functions"
164 This option is provided for the case where no in-kernel-tree
165 modules require CRC4 functions, but a module built outside
166 the kernel tree does. Such modules that use library CRC4
167 functions require M here.
170 tristate "CRC7 functions"
172 This option is provided for the case where no in-kernel-tree
173 modules require CRC7 functions, but a module built outside
174 the kernel tree does. Such modules that use library CRC7
175 functions require M here.
178 tristate "CRC32c (Castagnoli, et al) Cyclic Redundancy-Check"
182 This option is provided for the case where no in-kernel-tree
183 modules require CRC32c functions, but a module built outside the
184 kernel tree does. Such modules that use library CRC32c functions
185 require M here. See Castagnoli93.
186 Module will be libcrc32c.
189 tristate "CRC8 function"
191 This option provides CRC8 function. Drivers may select this
192 when they need to do cyclic redundancy check according CRC8
193 algorithm. Module will be called crc8.
200 depends on AUDIT && !AUDIT_ARCH
203 config AUDIT_ARCH_COMPAT_GENERIC
207 config AUDIT_COMPAT_GENERIC
209 depends on AUDIT_GENERIC && AUDIT_ARCH_COMPAT_GENERIC && COMPAT
212 config RANDOM32_SELFTEST
213 bool "PRNG perform self test on init"
216 This option enables the 32 bit PRNG library functions to perform a
217 self test on initialization.
220 # compression support is select'ed if needed
226 config 842_DECOMPRESS
240 config LZO_DECOMPRESS
246 config LZ4HC_COMPRESS
249 config LZ4_DECOMPRESS
256 config ZSTD_DECOMPRESS
260 source "lib/xz/Kconfig"
263 # These all provide a common interface (hence the apparent duplication with
264 # ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
266 config DECOMPRESS_GZIP
270 config DECOMPRESS_BZIP2
273 config DECOMPRESS_LZMA
280 config DECOMPRESS_LZO
281 select LZO_DECOMPRESS
284 config DECOMPRESS_LZ4
285 select LZ4_DECOMPRESS
289 # Generic allocator support is selected if needed
291 config GENERIC_ALLOCATOR
295 # reed solomon support is select'ed if needed
300 config REED_SOLOMON_ENC8
303 config REED_SOLOMON_DEC8
306 config REED_SOLOMON_ENC16
309 config REED_SOLOMON_DEC16
313 # BCH support is selected if needed
318 config BCH_CONST_PARAMS
321 Drivers may select this option to force specific constant
322 values for parameters 'm' (Galois field order) and 't'
323 (error correction capability). Those specific values must
324 be set by declaring default values for symbols BCH_CONST_M
326 Doing so will enable extra compiler optimizations,
327 improving encoding and decoding performance up to 2x for
328 usual (m,t) values (typically such that m*t < 200).
329 When this option is selected, the BCH library supports
330 only a single (m,t) configuration. This is mainly useful
331 for NAND flash board drivers requiring known, fixed BCH
338 Constant value for Galois field order 'm'. If 'k' is the
339 number of data bits to protect, 'm' should be chosen such
340 that (k + m*t) <= 2**m - 1.
341 Drivers should declare a default value for this symbol if
342 they select option BCH_CONST_PARAMS.
347 Constant value for error correction capability in bits 't'.
348 Drivers should declare a default value for this symbol if
349 they select option BCH_CONST_PARAMS.
352 # Textsearch support is select'ed if needed
357 config TEXTSEARCH_KMP
363 config TEXTSEARCH_FSM
372 Simple, embeddable, interval-tree. Can find the start of an
373 overlapping range in log(n) time and then iterate over all
374 overlapping nodes. The algorithm is implemented as an
379 Documentation/rbtree.txt
381 for more information.
383 config RADIX_TREE_MULTIORDER
386 config ASSOCIATIVE_ARRAY
389 Generic associative array. Can be searched and iterated over whilst
390 it is being modified. It is also reasonably quick to search and
391 modify. The algorithms are non-recursive, and the trees are highly
396 Documentation/assoc_array.txt
398 for more information.
406 config HAS_IOPORT_MAP
408 depends on HAS_IOMEM && !NO_IOPORT_MAP
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 bool "Test string functions"