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
59 config ARCH_USE_CMPXCHG_LOCKREF
62 config ARCH_HAS_FAST_MULTIPLIER
66 tristate "CRC-CCITT functions"
68 This option is provided for the case where no in-kernel-tree
69 modules require CRC-CCITT functions, but a module built outside
70 the kernel tree does. Such modules that use library CRC-CCITT
71 functions require M here.
74 tristate "CRC16 functions"
76 This option is provided for the case where no in-kernel-tree
77 modules require CRC16 functions, but a module built outside
78 the kernel tree does. Such modules that use library CRC16
79 functions require M here.
82 tristate "CRC calculation for the T10 Data Integrity Field"
84 select CRYPTO_CRCT10DIF
86 This option is only needed if a module that's not in the
87 kernel tree needs to calculate CRC checks for use with the
88 SCSI data integrity subsystem.
91 tristate "CRC ITU-T V.41 functions"
93 This option is provided for the case where no in-kernel-tree
94 modules require CRC ITU-T V.41 functions, but a module built outside
95 the kernel tree does. Such modules that use library CRC ITU-T V.41
96 functions require M here.
99 tristate "CRC32/CRC32c functions"
103 This option is provided for the case where no in-kernel-tree
104 modules require CRC32/CRC32c functions, but a module built outside
105 the kernel tree does. Such modules that use library CRC32/CRC32c
106 functions require M here.
108 config CRC32_SELFTEST
109 bool "CRC32 perform self test on init"
113 This option enables the CRC32 library functions to perform a
114 self test on initialization. The self test computes crc32_le
115 and crc32_be over byte strings with random alignment and length
116 and computes the total elapsed time and number of bytes processed.
119 prompt "CRC32 implementation"
121 default CRC32_SLICEBY8
123 This option allows a kernel builder to override the default choice
124 of CRC32 algorithm. Choose the default ("slice by 8") unless you
125 know that you need one of the others.
127 config CRC32_SLICEBY8
128 bool "Slice by 8 bytes"
130 Calculate checksum 8 bytes at a time with a clever slicing algorithm.
131 This is the fastest algorithm, but comes with a 8KiB lookup table.
132 Most modern processors have enough cache to hold this table without
135 This is the default implementation choice. Choose this one unless
136 you have a good reason not to.
138 config CRC32_SLICEBY4
139 bool "Slice by 4 bytes"
141 Calculate checksum 4 bytes at a time with a clever slicing algorithm.
142 This is a bit slower than slice by 8, but has a smaller 4KiB lookup
145 Only choose this option if you know what you are doing.
148 bool "Sarwate's Algorithm (one byte at a time)"
150 Calculate checksum a byte at a time using Sarwate's algorithm. This
151 is not particularly fast, but has a small 256 byte lookup table.
153 Only choose this option if you know what you are doing.
156 bool "Classic Algorithm (one bit at a time)"
158 Calculate checksum one bit at a time. This is VERY slow, but has
159 no lookup table. This is provided as a debugging option.
161 Only choose this option if you are debugging crc32.
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.
193 depends on AUDIT && !AUDIT_ARCH
196 config AUDIT_ARCH_COMPAT_GENERIC
200 config AUDIT_COMPAT_GENERIC
202 depends on AUDIT_GENERIC && AUDIT_ARCH_COMPAT_GENERIC && COMPAT
205 config RANDOM32_SELFTEST
206 bool "PRNG perform self test on init"
209 This option enables the 32 bit PRNG library functions to perform a
210 self test on initialization.
213 # compression support is select'ed if needed
218 config 842_DECOMPRESS
230 config LZO_DECOMPRESS
236 config LZ4HC_COMPRESS
239 config LZ4_DECOMPRESS
242 source "lib/xz/Kconfig"
245 # These all provide a common interface (hence the apparent duplication with
246 # ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
248 config DECOMPRESS_GZIP
252 config DECOMPRESS_BZIP2
255 config DECOMPRESS_LZMA
262 config DECOMPRESS_LZO
263 select LZO_DECOMPRESS
266 config DECOMPRESS_LZ4
267 select LZ4_DECOMPRESS
271 # Generic allocator support is selected if needed
273 config GENERIC_ALLOCATOR
277 # reed solomon support is select'ed if needed
282 config REED_SOLOMON_ENC8
285 config REED_SOLOMON_DEC8
288 config REED_SOLOMON_ENC16
291 config REED_SOLOMON_DEC16
295 # BCH support is selected if needed
300 config BCH_CONST_PARAMS
303 Drivers may select this option to force specific constant
304 values for parameters 'm' (Galois field order) and 't'
305 (error correction capability). Those specific values must
306 be set by declaring default values for symbols BCH_CONST_M
308 Doing so will enable extra compiler optimizations,
309 improving encoding and decoding performance up to 2x for
310 usual (m,t) values (typically such that m*t < 200).
311 When this option is selected, the BCH library supports
312 only a single (m,t) configuration. This is mainly useful
313 for NAND flash board drivers requiring known, fixed BCH
320 Constant value for Galois field order 'm'. If 'k' is the
321 number of data bits to protect, 'm' should be chosen such
322 that (k + m*t) <= 2**m - 1.
323 Drivers should declare a default value for this symbol if
324 they select option BCH_CONST_PARAMS.
329 Constant value for error correction capability in bits 't'.
330 Drivers should declare a default value for this symbol if
331 they select option BCH_CONST_PARAMS.
334 # Textsearch support is select'ed if needed
339 config TEXTSEARCH_KMP
345 config TEXTSEARCH_FSM
354 Simple, embeddable, interval-tree. Can find the start of an
355 overlapping range in log(n) time and then iterate over all
356 overlapping nodes. The algorithm is implemented as an
361 Documentation/rbtree.txt
363 for more information.
365 config ASSOCIATIVE_ARRAY
368 Generic associative array. Can be searched and iterated over whilst
369 it is being modified. It is also reasonably quick to search and
370 modify. The algorithms are non-recursive, and the trees are highly
375 Documentation/assoc_array.txt
377 for more information.
385 config HAS_IOPORT_MAP
387 depends on HAS_IOMEM && !NO_IOPORT_MAP
395 config CHECK_SIGNATURE
398 config CPUMASK_OFFSTACK
399 bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
401 Use dynamic allocation for cpumask_var_t, instead of putting
402 them on the stack. This is a bit more expensive, but avoids
414 # This actually supports modular compilation, but the module overhead
415 # is ridiculous for the amount of code involved. Until an out-of-tree
416 # driver asks for it, we'll just link it directly it into the kernel
417 # when required. Since we're ignoring out-of-tree users, there's also
418 # no need bother prompting for a manual decision:
419 # prompt "glob_match() function"
421 This option provides a glob_match function for performing
422 simple text pattern matching. It originated in the ATA code
423 to blacklist particular drive models, but other device drivers
424 may need similar functionality.
426 All drivers in the Linux kernel tree that require this function
427 should automatically select this option. Say N unless you
428 are compiling an out-of tree driver which tells you that it
432 bool "glob self-test on init"
436 This option enables a simple self-test of the glob_match
437 function on startup. It is primarily useful for people
438 working on the code to ensure they haven't introduced any
441 It only adds a little bit of code and slows kernel boot (or
442 module load) by a small amount, so you're welcome to play with
443 it, but you probably don't need it.
446 # Netlink attribute parsing support is select'ed if needed
452 # Generic 64-bit atomic support is selected if needed
454 config GENERIC_ATOMIC64
457 config ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
458 def_bool y if GENERIC_ATOMIC64
464 bool "Averaging functions"
466 This option is provided for the case where no in-kernel-tree
467 modules require averaging functions, but a module built outside
468 the kernel tree does. Such modules that use library averaging
469 functions require Y here.
477 tristate "CORDIC algorithm"
479 This option provides an implementation of the CORDIC algorithm;
480 calculations are in fixed point. Module will be called cordic.
483 bool "JEDEC DDR data"
485 Data from JEDEC specs for DDR SDRAM memories,
486 particularly the AC timing parameters and addressing
487 information. This data is useful for drivers handling
488 DDR SDRAM controllers.
494 Multiprecision maths library from GnuPG.
495 It is used to implement RSA digital signature verification,
496 which is used by IMA/EVM digital signature extension.
505 Digital signature verification. Currently only RSA is supported.
506 Implementation is done using GnuPG MPI library
509 # libfdt files, only selected if needed.
517 Enable fast lookup object identifier registry.
522 source "lib/fonts/Kconfig"
528 config ARCH_HAS_SG_CHAIN
531 config ARCH_HAS_PMEM_API