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 bool "CRC32 perform self test on init"
110 This option enables the CRC32 library functions to perform a
111 self test on initialization. The self test computes crc32_le
112 and crc32_be over byte strings with random alignment and length
113 and computes the total elapsed time and number of bytes processed.
116 prompt "CRC32 implementation"
118 default CRC32_SLICEBY8
120 This option allows a kernel builder to override the default choice
121 of CRC32 algorithm. Choose the default ("slice by 8") unless you
122 know that you need one of the others.
124 config CRC32_SLICEBY8
125 bool "Slice by 8 bytes"
127 Calculate checksum 8 bytes at a time with a clever slicing algorithm.
128 This is the fastest algorithm, but comes with a 8KiB lookup table.
129 Most modern processors have enough cache to hold this table without
132 This is the default implementation choice. Choose this one unless
133 you have a good reason not to.
135 config CRC32_SLICEBY4
136 bool "Slice by 4 bytes"
138 Calculate checksum 4 bytes at a time with a clever slicing algorithm.
139 This is a bit slower than slice by 8, but has a smaller 4KiB lookup
142 Only choose this option if you know what you are doing.
145 bool "Sarwate's Algorithm (one byte at a time)"
147 Calculate checksum a byte at a time using Sarwate's algorithm. This
148 is not particularly fast, but has a small 256 byte lookup table.
150 Only choose this option if you know what you are doing.
153 bool "Classic Algorithm (one bit at a time)"
155 Calculate checksum one bit at a time. This is VERY slow, but has
156 no lookup table. This is provided as a debugging option.
158 Only choose this option if you are debugging crc32.
163 tristate "CRC7 functions"
165 This option is provided for the case where no in-kernel-tree
166 modules require CRC7 functions, but a module built outside
167 the kernel tree does. Such modules that use library CRC7
168 functions require M here.
171 tristate "CRC32c (Castagnoli, et al) Cyclic Redundancy-Check"
175 This option is provided for the case where no in-kernel-tree
176 modules require CRC32c functions, but a module built outside the
177 kernel tree does. Such modules that use library CRC32c functions
178 require M here. See Castagnoli93.
179 Module will be libcrc32c.
182 tristate "CRC8 function"
184 This option provides CRC8 function. Drivers may select this
185 when they need to do cyclic redundancy check according CRC8
186 algorithm. Module will be called crc8.
190 depends on AUDIT && !AUDIT_ARCH
193 config AUDIT_ARCH_COMPAT_GENERIC
197 config AUDIT_COMPAT_GENERIC
199 depends on AUDIT_GENERIC && AUDIT_ARCH_COMPAT_GENERIC && COMPAT
202 config RANDOM32_SELFTEST
203 bool "PRNG perform self test on init"
206 This option enables the 32 bit PRNG library functions to perform a
207 self test on initialization.
210 # compression support is select'ed if needed
216 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
467 tristate "CORDIC algorithm"
469 This option provides an implementation of the CORDIC algorithm;
470 calculations are in fixed point. Module will be called cordic.
473 bool "JEDEC DDR data"
475 Data from JEDEC specs for DDR SDRAM memories,
476 particularly the AC timing parameters and addressing
477 information. This data is useful for drivers handling
478 DDR SDRAM controllers.
481 bool "IRQ polling library"
483 Helper library to poll interrupt mitigation using polling.
489 Multiprecision maths library from GnuPG.
490 It is used to implement RSA digital signature verification,
491 which is used by IMA/EVM digital signature extension.
500 Digital signature verification. Currently only RSA is supported.
501 Implementation is done using GnuPG MPI library
504 # libfdt files, only selected if needed.
512 Enable fast lookup object identifier registry.
517 source "lib/fonts/Kconfig"
522 Provides a helper to split scatterlists into chunks, each chunk being
523 a scatterlist. This should be selected by a driver or an API which
524 whishes to split a scatterlist amongst multiple DMA channels.
530 config ARCH_HAS_SG_CHAIN
533 config ARCH_HAS_PMEM_API
536 config ARCH_HAS_MMIO_FLUSH