2 # Library configuration
8 menu "Library routines"
16 config HAVE_ARCH_BITREVERSE
21 This option provides an config for the architecture which have instruction
22 can do bitreverse operation, we use the hardware instruction if the architecture
28 config GENERIC_STRNCPY_FROM_USER
31 config GENERIC_STRNLEN_USER
34 config GENERIC_NET_UTILS
37 config GENERIC_FIND_FIRST_BIT
40 config NO_GENERIC_PCI_IOPORT_MAP
43 config GENERIC_PCI_IOMAP
48 select GENERIC_PCI_IOMAP
60 config ARCH_USE_CMPXCHG_LOCKREF
63 config ARCH_HAS_FAST_MULTIPLIER
67 tristate "CRC-CCITT functions"
69 This option is provided for the case where no in-kernel-tree
70 modules require CRC-CCITT functions, but a module built outside
71 the kernel tree does. Such modules that use library CRC-CCITT
72 functions require M here.
75 tristate "CRC16 functions"
77 This option is provided for the case where no in-kernel-tree
78 modules require CRC16 functions, but a module built outside
79 the kernel tree does. Such modules that use library CRC16
80 functions require M here.
83 tristate "CRC calculation for the T10 Data Integrity Field"
85 select CRYPTO_CRCT10DIF
87 This option is only needed if a module that's not in the
88 kernel tree needs to calculate CRC checks for use with the
89 SCSI data integrity subsystem.
92 tristate "CRC ITU-T V.41 functions"
94 This option is provided for the case where no in-kernel-tree
95 modules require CRC ITU-T V.41 functions, but a module built outside
96 the kernel tree does. Such modules that use library CRC ITU-T V.41
97 functions require M here.
100 tristate "CRC32/CRC32c functions"
104 This option is provided for the case where no in-kernel-tree
105 modules require CRC32/CRC32c functions, but a module built outside
106 the kernel tree does. Such modules that use library CRC32/CRC32c
107 functions require M here.
109 config CRC32_SELFTEST
110 bool "CRC32 perform self test on init"
114 This option enables the CRC32 library functions to perform a
115 self test on initialization. The self test computes crc32_le
116 and crc32_be over byte strings with random alignment and length
117 and computes the total elapsed time and number of bytes processed.
120 prompt "CRC32 implementation"
122 default CRC32_SLICEBY8
124 This option allows a kernel builder to override the default choice
125 of CRC32 algorithm. Choose the default ("slice by 8") unless you
126 know that you need one of the others.
128 config CRC32_SLICEBY8
129 bool "Slice by 8 bytes"
131 Calculate checksum 8 bytes at a time with a clever slicing algorithm.
132 This is the fastest algorithm, but comes with a 8KiB lookup table.
133 Most modern processors have enough cache to hold this table without
136 This is the default implementation choice. Choose this one unless
137 you have a good reason not to.
139 config CRC32_SLICEBY4
140 bool "Slice by 4 bytes"
142 Calculate checksum 4 bytes at a time with a clever slicing algorithm.
143 This is a bit slower than slice by 8, but has a smaller 4KiB lookup
146 Only choose this option if you know what you are doing.
149 bool "Sarwate's Algorithm (one byte at a time)"
151 Calculate checksum a byte at a time using Sarwate's algorithm. This
152 is not particularly fast, but has a small 256 byte lookup table.
154 Only choose this option if you know what you are doing.
157 bool "Classic Algorithm (one bit at a time)"
159 Calculate checksum one bit at a time. This is VERY slow, but has
160 no lookup table. This is provided as a debugging option.
162 Only choose this option if you are debugging crc32.
167 tristate "CRC7 functions"
169 This option is provided for the case where no in-kernel-tree
170 modules require CRC7 functions, but a module built outside
171 the kernel tree does. Such modules that use library CRC7
172 functions require M here.
175 tristate "CRC32c (Castagnoli, et al) Cyclic Redundancy-Check"
179 This option is provided for the case where no in-kernel-tree
180 modules require CRC32c functions, but a module built outside the
181 kernel tree does. Such modules that use library CRC32c functions
182 require M here. See Castagnoli93.
183 Module will be libcrc32c.
186 tristate "CRC8 function"
188 This option provides CRC8 function. Drivers may select this
189 when they need to do cyclic redundancy check according CRC8
190 algorithm. Module will be called crc8.
194 depends on AUDIT && !AUDIT_ARCH
197 config AUDIT_ARCH_COMPAT_GENERIC
201 config AUDIT_COMPAT_GENERIC
203 depends on AUDIT_GENERIC && AUDIT_ARCH_COMPAT_GENERIC && COMPAT
206 config RANDOM32_SELFTEST
207 bool "PRNG perform self test on init"
210 This option enables the 32 bit PRNG library functions to perform a
211 self test on initialization.
214 # compression support is select'ed if needed
225 config LZO_DECOMPRESS
231 config LZ4HC_COMPRESS
234 config LZ4_DECOMPRESS
237 source "lib/xz/Kconfig"
240 # These all provide a common interface (hence the apparent duplication with
241 # ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
243 config DECOMPRESS_GZIP
247 config DECOMPRESS_BZIP2
250 config DECOMPRESS_LZMA
257 config DECOMPRESS_LZO
258 select LZO_DECOMPRESS
261 config DECOMPRESS_LZ4
262 select LZ4_DECOMPRESS
266 # Generic allocator support is selected if needed
268 config GENERIC_ALLOCATOR
272 # reed solomon support is select'ed if needed
277 config REED_SOLOMON_ENC8
280 config REED_SOLOMON_DEC8
283 config REED_SOLOMON_ENC16
286 config REED_SOLOMON_DEC16
290 # BCH support is selected if needed
295 config BCH_CONST_PARAMS
298 Drivers may select this option to force specific constant
299 values for parameters 'm' (Galois field order) and 't'
300 (error correction capability). Those specific values must
301 be set by declaring default values for symbols BCH_CONST_M
303 Doing so will enable extra compiler optimizations,
304 improving encoding and decoding performance up to 2x for
305 usual (m,t) values (typically such that m*t < 200).
306 When this option is selected, the BCH library supports
307 only a single (m,t) configuration. This is mainly useful
308 for NAND flash board drivers requiring known, fixed BCH
315 Constant value for Galois field order 'm'. If 'k' is the
316 number of data bits to protect, 'm' should be chosen such
317 that (k + m*t) <= 2**m - 1.
318 Drivers should declare a default value for this symbol if
319 they select option BCH_CONST_PARAMS.
324 Constant value for error correction capability in bits 't'.
325 Drivers should declare a default value for this symbol if
326 they select option BCH_CONST_PARAMS.
329 # Textsearch support is select'ed if needed
334 config TEXTSEARCH_KMP
340 config TEXTSEARCH_FSM
349 Simple, embeddable, interval-tree. Can find the start of an
350 overlapping range in log(n) time and then iterate over all
351 overlapping nodes. The algorithm is implemented as an
356 Documentation/rbtree.txt
358 for more information.
360 config ASSOCIATIVE_ARRAY
363 Generic associative array. Can be searched and iterated over whilst
364 it is being modified. It is also reasonably quick to search and
365 modify. The algorithms are non-recursive, and the trees are highly
370 Documentation/assoc_array.txt
372 for more information.
380 config HAS_IOPORT_MAP
382 depends on HAS_IOMEM && !NO_IOPORT_MAP
390 config CHECK_SIGNATURE
393 config CPUMASK_OFFSTACK
394 bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
396 Use dynamic allocation for cpumask_var_t, instead of putting
397 them on the stack. This is a bit more expensive, but avoids
400 config DISABLE_OBSOLETE_CPUMASK_FUNCTIONS
401 bool "Disable obsolete cpumask functions" if DEBUG_PER_CPU_MAPS
413 # This actually supports modular compilation, but the module overhead
414 # is ridiculous for the amount of code involved. Until an out-of-tree
415 # driver asks for it, we'll just link it directly it into the kernel
416 # when required. Since we're ignoring out-of-tree users, there's also
417 # no need bother prompting for a manual decision:
418 # prompt "glob_match() function"
420 This option provides a glob_match function for performing
421 simple text pattern matching. It originated in the ATA code
422 to blacklist particular drive models, but other device drivers
423 may need similar functionality.
425 All drivers in the Linux kernel tree that require this function
426 should automatically select this option. Say N unless you
427 are compiling an out-of tree driver which tells you that it
431 bool "glob self-test on init"
435 This option enables a simple self-test of the glob_match
436 function on startup. It is primarily useful for people
437 working on the code to ensure they haven't introduced any
440 It only adds a little bit of code and slows kernel boot (or
441 module load) by a small amount, so you're welcome to play with
442 it, but you probably don't need it.
445 # Netlink attribute parsing support is select'ed if needed
451 # Generic 64-bit atomic support is selected if needed
453 config GENERIC_ATOMIC64
456 config ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
457 def_bool y if GENERIC_ATOMIC64
463 bool "Averaging functions"
465 This option is provided for the case where no in-kernel-tree
466 modules require averaging functions, but a module built outside
467 the kernel tree does. Such modules that use library averaging
468 functions require Y here.
476 tristate "CORDIC algorithm"
478 This option provides an implementation of the CORDIC algorithm;
479 calculations are in fixed point. Module will be called cordic.
482 bool "JEDEC DDR data"
484 Data from JEDEC specs for DDR SDRAM memories,
485 particularly the AC timing parameters and addressing
486 information. This data is useful for drivers handling
487 DDR SDRAM controllers.
493 Multiprecision maths library from GnuPG.
494 It is used to implement RSA digital signature verification,
495 which is used by IMA/EVM digital signature extension.
504 Digital signature verification. Currently only RSA is supported.
505 Implementation is done using GnuPG MPI library
508 # libfdt files, only selected if needed.
516 Enable fast lookup object identifier registry.
521 source "lib/fonts/Kconfig"
527 config ARCH_HAS_SG_CHAIN