2 # Library configuration
8 menu "Library routines"
16 config HAVE_ARCH_BITREVERSE
20 This option enables the use of hardware bit-reversal instructions on
21 architectures which support such operations.
26 config GENERIC_STRNCPY_FROM_USER
29 config GENERIC_STRNLEN_USER
32 config GENERIC_NET_UTILS
35 config GENERIC_FIND_FIRST_BIT
38 config NO_GENERIC_PCI_IOPORT_MAP
41 config GENERIC_PCI_IOMAP
46 select GENERIC_PCI_IOMAP
55 config ARCH_USE_CMPXCHG_LOCKREF
58 config ARCH_HAS_FAST_MULTIPLIER
62 tristate "CRC-CCITT functions"
64 This option is provided for the case where no in-kernel-tree
65 modules require CRC-CCITT functions, but a module built outside
66 the kernel tree does. Such modules that use library CRC-CCITT
67 functions require M here.
70 tristate "CRC16 functions"
72 This option is provided for the case where no in-kernel-tree
73 modules require CRC16 functions, but a module built outside
74 the kernel tree does. Such modules that use library CRC16
75 functions require M here.
78 tristate "CRC calculation for the T10 Data Integrity Field"
80 select CRYPTO_CRCT10DIF
82 This option is only needed if a module that's not in the
83 kernel tree needs to calculate CRC checks for use with the
84 SCSI data integrity subsystem.
87 tristate "CRC ITU-T V.41 functions"
89 This option is provided for the case where no in-kernel-tree
90 modules require CRC ITU-T V.41 functions, but a module built outside
91 the kernel tree does. Such modules that use library CRC ITU-T V.41
92 functions require M here.
95 tristate "CRC32/CRC32c functions"
99 This option is provided for the case where no in-kernel-tree
100 modules require CRC32/CRC32c functions, but a module built outside
101 the kernel tree does. Such modules that use library CRC32/CRC32c
102 functions require M here.
104 config CRC32_SELFTEST
105 tristate "CRC32 perform self test on init"
108 This option enables the CRC32 library functions to perform a
109 self test on initialization. The self test computes crc32_le
110 and crc32_be over byte strings with random alignment and length
111 and computes the total elapsed time and number of bytes processed.
114 prompt "CRC32 implementation"
116 default CRC32_SLICEBY8
118 This option allows a kernel builder to override the default choice
119 of CRC32 algorithm. Choose the default ("slice by 8") unless you
120 know that you need one of the others.
122 config CRC32_SLICEBY8
123 bool "Slice by 8 bytes"
125 Calculate checksum 8 bytes at a time with a clever slicing algorithm.
126 This is the fastest algorithm, but comes with a 8KiB lookup table.
127 Most modern processors have enough cache to hold this table without
130 This is the default implementation choice. Choose this one unless
131 you have a good reason not to.
133 config CRC32_SLICEBY4
134 bool "Slice by 4 bytes"
136 Calculate checksum 4 bytes at a time with a clever slicing algorithm.
137 This is a bit slower than slice by 8, but has a smaller 4KiB lookup
140 Only choose this option if you know what you are doing.
143 bool "Sarwate's Algorithm (one byte at a time)"
145 Calculate checksum a byte at a time using Sarwate's algorithm. This
146 is not particularly fast, but has a small 256 byte lookup table.
148 Only choose this option if you know what you are doing.
151 bool "Classic Algorithm (one bit at a time)"
153 Calculate checksum one bit at a time. This is VERY slow, but has
154 no lookup table. This is provided as a debugging option.
156 Only choose this option if you are debugging crc32.
161 tristate "CRC4 functions"
163 This option is provided for the case where no in-kernel-tree
164 modules require CRC4 functions, but a module built outside
165 the kernel tree does. Such modules that use library CRC4
166 functions require M here.
169 tristate "CRC7 functions"
171 This option is provided for the case where no in-kernel-tree
172 modules require CRC7 functions, but a module built outside
173 the kernel tree does. Such modules that use library CRC7
174 functions require M here.
177 tristate "CRC32c (Castagnoli, et al) Cyclic Redundancy-Check"
181 This option is provided for the case where no in-kernel-tree
182 modules require CRC32c functions, but a module built outside the
183 kernel tree does. Such modules that use library CRC32c functions
184 require M here. See Castagnoli93.
185 Module will be libcrc32c.
188 tristate "CRC8 function"
190 This option provides CRC8 function. Drivers may select this
191 when they need to do cyclic redundancy check according CRC8
192 algorithm. Module will be called crc8.
199 depends on AUDIT && !AUDIT_ARCH
202 config AUDIT_ARCH_COMPAT_GENERIC
206 config AUDIT_COMPAT_GENERIC
208 depends on AUDIT_GENERIC && AUDIT_ARCH_COMPAT_GENERIC && COMPAT
211 config RANDOM32_SELFTEST
212 bool "PRNG perform self test on init"
215 This option enables the 32 bit PRNG library functions to perform a
216 self test on initialization.
219 # compression support is select'ed if needed
225 config 842_DECOMPRESS
239 config LZO_DECOMPRESS
245 config LZ4HC_COMPRESS
248 config LZ4_DECOMPRESS
255 config ZSTD_DECOMPRESS
259 source "lib/xz/Kconfig"
262 # These all provide a common interface (hence the apparent duplication with
263 # ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
265 config DECOMPRESS_GZIP
269 config DECOMPRESS_BZIP2
272 config DECOMPRESS_LZMA
279 config DECOMPRESS_LZO
280 select LZO_DECOMPRESS
283 config DECOMPRESS_LZ4
284 select LZ4_DECOMPRESS
288 # Generic allocator support is selected if needed
290 config GENERIC_ALLOCATOR
294 # reed solomon support is select'ed if needed
299 config REED_SOLOMON_ENC8
302 config REED_SOLOMON_DEC8
305 config REED_SOLOMON_ENC16
308 config REED_SOLOMON_DEC16
312 # BCH support is selected if needed
317 config BCH_CONST_PARAMS
320 Drivers may select this option to force specific constant
321 values for parameters 'm' (Galois field order) and 't'
322 (error correction capability). Those specific values must
323 be set by declaring default values for symbols BCH_CONST_M
325 Doing so will enable extra compiler optimizations,
326 improving encoding and decoding performance up to 2x for
327 usual (m,t) values (typically such that m*t < 200).
328 When this option is selected, the BCH library supports
329 only a single (m,t) configuration. This is mainly useful
330 for NAND flash board drivers requiring known, fixed BCH
337 Constant value for Galois field order 'm'. If 'k' is the
338 number of data bits to protect, 'm' should be chosen such
339 that (k + m*t) <= 2**m - 1.
340 Drivers should declare a default value for this symbol if
341 they select option BCH_CONST_PARAMS.
346 Constant value for error correction capability in bits 't'.
347 Drivers should declare a default value for this symbol if
348 they select option BCH_CONST_PARAMS.
351 # Textsearch support is select'ed if needed
356 config TEXTSEARCH_KMP
362 config TEXTSEARCH_FSM
371 Simple, embeddable, interval-tree. Can find the start of an
372 overlapping range in log(n) time and then iterate over all
373 overlapping nodes. The algorithm is implemented as an
378 Documentation/rbtree.txt
380 for more information.
382 config RADIX_TREE_MULTIORDER
385 config ASSOCIATIVE_ARRAY
388 Generic associative array. Can be searched and iterated over whilst
389 it is being modified. It is also reasonably quick to search and
390 modify. The algorithms are non-recursive, and the trees are highly
395 Documentation/assoc_array.txt
397 for more information.
405 config HAS_IOPORT_MAP
407 depends on HAS_IOMEM && !NO_IOPORT_MAP
421 depends on HAS_DMA && (!64BIT || ARCH_DMA_ADDR_T_64BIT)
426 depends on HAS_DMA && (!64BIT || ARCH_DMA_ADDR_T_64BIT)
429 config CHECK_SIGNATURE
432 config CPUMASK_OFFSTACK
433 bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
435 Use dynamic allocation for cpumask_var_t, instead of putting
436 them on the stack. This is a bit more expensive, but avoids
448 # This actually supports modular compilation, but the module overhead
449 # is ridiculous for the amount of code involved. Until an out-of-tree
450 # driver asks for it, we'll just link it directly it into the kernel
451 # when required. Since we're ignoring out-of-tree users, there's also
452 # no need bother prompting for a manual decision:
453 # prompt "glob_match() function"
455 This option provides a glob_match function for performing
456 simple text pattern matching. It originated in the ATA code
457 to blacklist particular drive models, but other device drivers
458 may need similar functionality.
460 All drivers in the Linux kernel tree that require this function
461 should automatically select this option. Say N unless you
462 are compiling an out-of tree driver which tells you that it
466 tristate "glob self-test on init"
469 This option enables a simple self-test of the glob_match
470 function on startup. It is primarily useful for people
471 working on the code to ensure they haven't introduced any
474 It only adds a little bit of code and slows kernel boot (or
475 module load) by a small amount, so you're welcome to play with
476 it, but you probably don't need it.
479 # Netlink attribute parsing support is select'ed if needed
485 # Generic 64-bit atomic support is selected if needed
487 config GENERIC_ATOMIC64
497 tristate "CORDIC algorithm"
499 This option provides an implementation of the CORDIC algorithm;
500 calculations are in fixed point. Module will be called cordic.
503 bool "JEDEC DDR data"
505 Data from JEDEC specs for DDR SDRAM memories,
506 particularly the AC timing parameters and addressing
507 information. This data is useful for drivers handling
508 DDR SDRAM controllers.
511 bool "IRQ polling library"
513 Helper library to poll interrupt mitigation using polling.
519 Multiprecision maths library from GnuPG.
520 It is used to implement RSA digital signature verification,
521 which is used by IMA/EVM digital signature extension.
530 Digital signature verification. Currently only RSA is supported.
531 Implementation is done using GnuPG MPI library
534 # libfdt files, only selected if needed.
542 Enable fast lookup object identifier registry.
547 source "lib/fonts/Kconfig"
552 Provides a helper to split scatterlists into chunks, each chunk being
553 a scatterlist. This should be selected by a driver or an API which
554 whishes to split a scatterlist amongst multiple DMA channels.
559 Provides a helper to allocate chained scatterlists. This should be
560 selected by a driver or an API which whishes to allocate chained
567 config ARCH_HAS_SG_CHAIN
570 config ARCH_HAS_PMEM_API
573 config ARCH_HAS_UACCESS_FLUSHCACHE
584 tristate "parman" if COMPILE_TEST
589 config STRING_SELFTEST
590 bool "Test string functions"