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.
189 tristate "CRC64 ECMA function"
191 This option provides CRC64 ECMA function. Drivers may select this
192 when they need to do cyclic redundancy check according to the CRC64
197 depends on AUDIT && !AUDIT_ARCH
200 config AUDIT_ARCH_COMPAT_GENERIC
204 config AUDIT_COMPAT_GENERIC
206 depends on AUDIT_GENERIC && AUDIT_ARCH_COMPAT_GENERIC && COMPAT
209 config RANDOM32_SELFTEST
210 bool "PRNG perform self test on init"
213 This option enables the 32 bit PRNG library functions to perform a
214 self test on initialization.
217 # compression support is select'ed if needed
223 config 842_DECOMPRESS
237 config LZO_DECOMPRESS
243 config LZ4HC_COMPRESS
246 config LZ4_DECOMPRESS
249 source "lib/xz/Kconfig"
252 # These all provide a common interface (hence the apparent duplication with
253 # ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
255 config DECOMPRESS_GZIP
259 config DECOMPRESS_BZIP2
262 config DECOMPRESS_LZMA
269 config DECOMPRESS_LZO
270 select LZO_DECOMPRESS
273 config DECOMPRESS_LZ4
274 select LZ4_DECOMPRESS
278 # Generic allocator support is selected if needed
280 config GENERIC_ALLOCATOR
284 # reed solomon support is select'ed if needed
289 config REED_SOLOMON_ENC8
292 config REED_SOLOMON_DEC8
295 config REED_SOLOMON_ENC16
298 config REED_SOLOMON_DEC16
302 # BCH support is selected if needed
307 config BCH_CONST_PARAMS
310 Drivers may select this option to force specific constant
311 values for parameters 'm' (Galois field order) and 't'
312 (error correction capability). Those specific values must
313 be set by declaring default values for symbols BCH_CONST_M
315 Doing so will enable extra compiler optimizations,
316 improving encoding and decoding performance up to 2x for
317 usual (m,t) values (typically such that m*t < 200).
318 When this option is selected, the BCH library supports
319 only a single (m,t) configuration. This is mainly useful
320 for NAND flash board drivers requiring known, fixed BCH
327 Constant value for Galois field order 'm'. If 'k' is the
328 number of data bits to protect, 'm' should be chosen such
329 that (k + m*t) <= 2**m - 1.
330 Drivers should declare a default value for this symbol if
331 they select option BCH_CONST_PARAMS.
336 Constant value for error correction capability in bits 't'.
337 Drivers should declare a default value for this symbol if
338 they select option BCH_CONST_PARAMS.
341 # Textsearch support is select'ed if needed
346 config TEXTSEARCH_KMP
352 config TEXTSEARCH_FSM
361 Simple, embeddable, interval-tree. Can find the start of an
362 overlapping range in log(n) time and then iterate over all
363 overlapping nodes. The algorithm is implemented as an
368 Documentation/rbtree.txt
370 for more information.
372 config ASSOCIATIVE_ARRAY
375 Generic associative array. Can be searched and iterated over whilst
376 it is being modified. It is also reasonably quick to search and
377 modify. The algorithms are non-recursive, and the trees are highly
382 Documentation/assoc_array.txt
384 for more information.
392 config HAS_IOPORT_MAP
394 depends on HAS_IOMEM && !NO_IOPORT_MAP
402 config CHECK_SIGNATURE
405 config CPUMASK_OFFSTACK
406 bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
408 Use dynamic allocation for cpumask_var_t, instead of putting
409 them on the stack. This is a bit more expensive, but avoids
421 # This actually supports modular compilation, but the module overhead
422 # is ridiculous for the amount of code involved. Until an out-of-tree
423 # driver asks for it, we'll just link it directly it into the kernel
424 # when required. Since we're ignoring out-of-tree users, there's also
425 # no need bother prompting for a manual decision:
426 # prompt "glob_match() function"
428 This option provides a glob_match function for performing
429 simple text pattern matching. It originated in the ATA code
430 to blacklist particular drive models, but other device drivers
431 may need similar functionality.
433 All drivers in the Linux kernel tree that require this function
434 should automatically select this option. Say N unless you
435 are compiling an out-of tree driver which tells you that it
439 bool "glob self-test on init"
443 This option enables a simple self-test of the glob_match
444 function on startup. It is primarily useful for people
445 working on the code to ensure they haven't introduced any
448 It only adds a little bit of code and slows kernel boot (or
449 module load) by a small amount, so you're welcome to play with
450 it, but you probably don't need it.
453 # Netlink attribute parsing support is select'ed if needed
459 # Generic 64-bit atomic support is selected if needed
461 config GENERIC_ATOMIC64
464 config ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
465 def_bool y if GENERIC_ATOMIC64
474 tristate "CORDIC algorithm"
476 This option provides an implementation of the CORDIC algorithm;
477 calculations are in fixed point. Module will be called cordic.
480 bool "JEDEC DDR data"
482 Data from JEDEC specs for DDR SDRAM memories,
483 particularly the AC timing parameters and addressing
484 information. This data is useful for drivers handling
485 DDR SDRAM controllers.
488 bool "IRQ polling library"
490 Helper library to poll interrupt mitigation using polling.
496 Multiprecision maths library from GnuPG.
497 It is used to implement RSA digital signature verification,
498 which is used by IMA/EVM digital signature extension.
507 Digital signature verification. Currently only RSA is supported.
508 Implementation is done using GnuPG MPI library
511 # libfdt files, only selected if needed.
519 Enable fast lookup object identifier registry.
524 source "lib/fonts/Kconfig"
529 Provides a helper to split scatterlists into chunks, each chunk being
530 a scatterlist. This should be selected by a driver or an API which
531 whishes to split a scatterlist amongst multiple DMA channels.
537 config ARCH_HAS_SG_CHAIN
540 config ARCH_HAS_PMEM_API
543 config ARCH_HAS_MMIO_FLUSH