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 tristate "CRC32 perform self test on init"
109 This option enables the CRC32 library functions to perform a
110 self test on initialization. The self test computes crc32_le
111 and crc32_be over byte strings with random alignment and length
112 and computes the total elapsed time and number of bytes processed.
115 prompt "CRC32 implementation"
117 default CRC32_SLICEBY8
119 This option allows a kernel builder to override the default choice
120 of CRC32 algorithm. Choose the default ("slice by 8") unless you
121 know that you need one of the others.
123 config CRC32_SLICEBY8
124 bool "Slice by 8 bytes"
126 Calculate checksum 8 bytes at a time with a clever slicing algorithm.
127 This is the fastest algorithm, but comes with a 8KiB lookup table.
128 Most modern processors have enough cache to hold this table without
131 This is the default implementation choice. Choose this one unless
132 you have a good reason not to.
134 config CRC32_SLICEBY4
135 bool "Slice by 4 bytes"
137 Calculate checksum 4 bytes at a time with a clever slicing algorithm.
138 This is a bit slower than slice by 8, but has a smaller 4KiB lookup
141 Only choose this option if you know what you are doing.
144 bool "Sarwate's Algorithm (one byte at a time)"
146 Calculate checksum a byte at a time using Sarwate's algorithm. This
147 is not particularly fast, but has a small 256 byte lookup table.
149 Only choose this option if you know what you are doing.
152 bool "Classic Algorithm (one bit at a time)"
154 Calculate checksum one bit at a time. This is VERY slow, but has
155 no lookup table. This is provided as a debugging option.
157 Only choose this option if you are debugging crc32.
162 tristate "CRC7 functions"
164 This option is provided for the case where no in-kernel-tree
165 modules require CRC7 functions, but a module built outside
166 the kernel tree does. Such modules that use library CRC7
167 functions require M here.
170 tristate "CRC32c (Castagnoli, et al) Cyclic Redundancy-Check"
174 This option is provided for the case where no in-kernel-tree
175 modules require CRC32c functions, but a module built outside the
176 kernel tree does. Such modules that use library CRC32c functions
177 require M here. See Castagnoli93.
178 Module will be libcrc32c.
181 tristate "CRC8 function"
183 This option provides CRC8 function. Drivers may select this
184 when they need to do cyclic redundancy check according CRC8
185 algorithm. Module will be called crc8.
189 depends on AUDIT && !AUDIT_ARCH
192 config AUDIT_ARCH_COMPAT_GENERIC
196 config AUDIT_COMPAT_GENERIC
198 depends on AUDIT_GENERIC && AUDIT_ARCH_COMPAT_GENERIC && COMPAT
201 config RANDOM32_SELFTEST
202 bool "PRNG perform self test on init"
205 This option enables the 32 bit PRNG library functions to perform a
206 self test on initialization.
209 # compression support is select'ed if needed
215 config 842_DECOMPRESS
229 config LZO_DECOMPRESS
235 config LZ4HC_COMPRESS
238 config LZ4_DECOMPRESS
241 source "lib/xz/Kconfig"
244 # These all provide a common interface (hence the apparent duplication with
245 # ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
247 config DECOMPRESS_GZIP
251 config DECOMPRESS_BZIP2
254 config DECOMPRESS_LZMA
261 config DECOMPRESS_LZO
262 select LZO_DECOMPRESS
265 config DECOMPRESS_LZ4
266 select LZ4_DECOMPRESS
270 # Generic allocator support is selected if needed
272 config GENERIC_ALLOCATOR
276 # reed solomon support is select'ed if needed
281 config REED_SOLOMON_ENC8
284 config REED_SOLOMON_DEC8
287 config REED_SOLOMON_ENC16
290 config REED_SOLOMON_DEC16
294 # BCH support is selected if needed
299 config BCH_CONST_PARAMS
302 Drivers may select this option to force specific constant
303 values for parameters 'm' (Galois field order) and 't'
304 (error correction capability). Those specific values must
305 be set by declaring default values for symbols BCH_CONST_M
307 Doing so will enable extra compiler optimizations,
308 improving encoding and decoding performance up to 2x for
309 usual (m,t) values (typically such that m*t < 200).
310 When this option is selected, the BCH library supports
311 only a single (m,t) configuration. This is mainly useful
312 for NAND flash board drivers requiring known, fixed BCH
319 Constant value for Galois field order 'm'. If 'k' is the
320 number of data bits to protect, 'm' should be chosen such
321 that (k + m*t) <= 2**m - 1.
322 Drivers should declare a default value for this symbol if
323 they select option BCH_CONST_PARAMS.
328 Constant value for error correction capability in bits 't'.
329 Drivers should declare a default value for this symbol if
330 they select option BCH_CONST_PARAMS.
333 # Textsearch support is select'ed if needed
338 config TEXTSEARCH_KMP
344 config TEXTSEARCH_FSM
353 Simple, embeddable, interval-tree. Can find the start of an
354 overlapping range in log(n) time and then iterate over all
355 overlapping nodes. The algorithm is implemented as an
360 Documentation/rbtree.txt
362 for more information.
364 config RADIX_TREE_MULTIORDER
367 config ASSOCIATIVE_ARRAY
370 Generic associative array. Can be searched and iterated over whilst
371 it is being modified. It is also reasonably quick to search and
372 modify. The algorithms are non-recursive, and the trees are highly
377 Documentation/assoc_array.txt
379 for more information.
387 config HAS_IOPORT_MAP
389 depends on HAS_IOMEM && !NO_IOPORT_MAP
399 depends on HAS_DMA && (!64BIT || ARCH_DMA_ADDR_T_64BIT)
404 depends on HAS_DMA && (!64BIT || ARCH_DMA_ADDR_T_64BIT)
407 config CHECK_SIGNATURE
410 config CPUMASK_OFFSTACK
411 bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
413 Use dynamic allocation for cpumask_var_t, instead of putting
414 them on the stack. This is a bit more expensive, but avoids
426 # This actually supports modular compilation, but the module overhead
427 # is ridiculous for the amount of code involved. Until an out-of-tree
428 # driver asks for it, we'll just link it directly it into the kernel
429 # when required. Since we're ignoring out-of-tree users, there's also
430 # no need bother prompting for a manual decision:
431 # prompt "glob_match() function"
433 This option provides a glob_match function for performing
434 simple text pattern matching. It originated in the ATA code
435 to blacklist particular drive models, but other device drivers
436 may need similar functionality.
438 All drivers in the Linux kernel tree that require this function
439 should automatically select this option. Say N unless you
440 are compiling an out-of tree driver which tells you that it
444 tristate "glob self-test on init"
447 This option enables a simple self-test of the glob_match
448 function on startup. It is primarily useful for people
449 working on the code to ensure they haven't introduced any
452 It only adds a little bit of code and slows kernel boot (or
453 module load) by a small amount, so you're welcome to play with
454 it, but you probably don't need it.
457 # Netlink attribute parsing support is select'ed if needed
463 # Generic 64-bit atomic support is selected if needed
465 config GENERIC_ATOMIC64
475 tristate "CORDIC algorithm"
477 This option provides an implementation of the CORDIC algorithm;
478 calculations are in fixed point. Module will be called cordic.
481 bool "JEDEC DDR data"
483 Data from JEDEC specs for DDR SDRAM memories,
484 particularly the AC timing parameters and addressing
485 information. This data is useful for drivers handling
486 DDR SDRAM controllers.
489 bool "IRQ polling library"
491 Helper library to poll interrupt mitigation using polling.
497 Multiprecision maths library from GnuPG.
498 It is used to implement RSA digital signature verification,
499 which is used by IMA/EVM digital signature extension.
508 Digital signature verification. Currently only RSA is supported.
509 Implementation is done using GnuPG MPI library
512 # libfdt files, only selected if needed.
520 Enable fast lookup object identifier registry.
525 source "lib/fonts/Kconfig"
530 Provides a helper to split scatterlists into chunks, each chunk being
531 a scatterlist. This should be selected by a driver or an API which
532 whishes to split a scatterlist amongst multiple DMA channels.
537 Provides a helper to allocate chained scatterlists. This should be
538 selected by a driver or an API which whishes to allocate chained
545 config ARCH_HAS_SG_CHAIN
548 config ARCH_HAS_PMEM_API
551 config ARCH_HAS_MMIO_FLUSH
562 tristate "parman" if COMPILE_TEST