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 bool "Generic logical IO management"
64 def_bool y if PCI && (ARM || UNICORE32 || MICROBLAZE || ARM64)
66 For some architectures, there are no IO space. To support the
67 accesses to legacy I/O devices on those architectures, kernel
68 implemented the memory mapped I/O mechanism based on bridge bus
69 supports. But for some buses which do not support MMIO, the
70 peripherals there should be accessed with device-specific way.
71 To abstract those different I/O accesses into unified I/O accessors,
72 this option provide a generic I/O space management way after mapping
73 the device I/O to system logical/fake I/O and help to hide all the
77 tristate "CRC-CCITT functions"
79 This option is provided for the case where no in-kernel-tree
80 modules require CRC-CCITT functions, but a module built outside
81 the kernel tree does. Such modules that use library CRC-CCITT
82 functions require M here.
85 tristate "CRC16 functions"
87 This option is provided for the case where no in-kernel-tree
88 modules require CRC16 functions, but a module built outside
89 the kernel tree does. Such modules that use library CRC16
90 functions require M here.
93 tristate "CRC calculation for the T10 Data Integrity Field"
95 select CRYPTO_CRCT10DIF
97 This option is only needed if a module that's not in the
98 kernel tree needs to calculate CRC checks for use with the
99 SCSI data integrity subsystem.
102 tristate "CRC ITU-T V.41 functions"
104 This option is provided for the case where no in-kernel-tree
105 modules require CRC ITU-T V.41 functions, but a module built outside
106 the kernel tree does. Such modules that use library CRC ITU-T V.41
107 functions require M here.
110 tristate "CRC32/CRC32c functions"
114 This option is provided for the case where no in-kernel-tree
115 modules require CRC32/CRC32c functions, but a module built outside
116 the kernel tree does. Such modules that use library CRC32/CRC32c
117 functions require M here.
119 config CRC32_SELFTEST
120 tristate "CRC32 perform self test on init"
123 This option enables the CRC32 library functions to perform a
124 self test on initialization. The self test computes crc32_le
125 and crc32_be over byte strings with random alignment and length
126 and computes the total elapsed time and number of bytes processed.
129 prompt "CRC32 implementation"
131 default CRC32_SLICEBY8
133 This option allows a kernel builder to override the default choice
134 of CRC32 algorithm. Choose the default ("slice by 8") unless you
135 know that you need one of the others.
137 config CRC32_SLICEBY8
138 bool "Slice by 8 bytes"
140 Calculate checksum 8 bytes at a time with a clever slicing algorithm.
141 This is the fastest algorithm, but comes with a 8KiB lookup table.
142 Most modern processors have enough cache to hold this table without
145 This is the default implementation choice. Choose this one unless
146 you have a good reason not to.
148 config CRC32_SLICEBY4
149 bool "Slice by 4 bytes"
151 Calculate checksum 4 bytes at a time with a clever slicing algorithm.
152 This is a bit slower than slice by 8, but has a smaller 4KiB lookup
155 Only choose this option if you know what you are doing.
158 bool "Sarwate's Algorithm (one byte at a time)"
160 Calculate checksum a byte at a time using Sarwate's algorithm. This
161 is not particularly fast, but has a small 256 byte lookup table.
163 Only choose this option if you know what you are doing.
166 bool "Classic Algorithm (one bit at a time)"
168 Calculate checksum one bit at a time. This is VERY slow, but has
169 no lookup table. This is provided as a debugging option.
171 Only choose this option if you are debugging crc32.
176 tristate "CRC4 functions"
178 This option is provided for the case where no in-kernel-tree
179 modules require CRC4 functions, but a module built outside
180 the kernel tree does. Such modules that use library CRC4
181 functions require M here.
184 tristate "CRC7 functions"
186 This option is provided for the case where no in-kernel-tree
187 modules require CRC7 functions, but a module built outside
188 the kernel tree does. Such modules that use library CRC7
189 functions require M here.
192 tristate "CRC32c (Castagnoli, et al) Cyclic Redundancy-Check"
196 This option is provided for the case where no in-kernel-tree
197 modules require CRC32c functions, but a module built outside the
198 kernel tree does. Such modules that use library CRC32c functions
199 require M here. See Castagnoli93.
200 Module will be libcrc32c.
203 tristate "CRC8 function"
205 This option provides CRC8 function. Drivers may select this
206 when they need to do cyclic redundancy check according CRC8
207 algorithm. Module will be called crc8.
211 depends on AUDIT && !AUDIT_ARCH
214 config AUDIT_ARCH_COMPAT_GENERIC
218 config AUDIT_COMPAT_GENERIC
220 depends on AUDIT_GENERIC && AUDIT_ARCH_COMPAT_GENERIC && COMPAT
223 config RANDOM32_SELFTEST
224 bool "PRNG perform self test on init"
227 This option enables the 32 bit PRNG library functions to perform a
228 self test on initialization.
231 # compression support is select'ed if needed
237 config 842_DECOMPRESS
251 config LZO_DECOMPRESS
257 config LZ4HC_COMPRESS
260 config LZ4_DECOMPRESS
263 source "lib/xz/Kconfig"
266 # These all provide a common interface (hence the apparent duplication with
267 # ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
269 config DECOMPRESS_GZIP
273 config DECOMPRESS_BZIP2
276 config DECOMPRESS_LZMA
283 config DECOMPRESS_LZO
284 select LZO_DECOMPRESS
287 config DECOMPRESS_LZ4
288 select LZ4_DECOMPRESS
292 # Generic allocator support is selected if needed
294 config GENERIC_ALLOCATOR
298 # reed solomon support is select'ed if needed
303 config REED_SOLOMON_ENC8
306 config REED_SOLOMON_DEC8
309 config REED_SOLOMON_ENC16
312 config REED_SOLOMON_DEC16
316 # BCH support is selected if needed
321 config BCH_CONST_PARAMS
324 Drivers may select this option to force specific constant
325 values for parameters 'm' (Galois field order) and 't'
326 (error correction capability). Those specific values must
327 be set by declaring default values for symbols BCH_CONST_M
329 Doing so will enable extra compiler optimizations,
330 improving encoding and decoding performance up to 2x for
331 usual (m,t) values (typically such that m*t < 200).
332 When this option is selected, the BCH library supports
333 only a single (m,t) configuration. This is mainly useful
334 for NAND flash board drivers requiring known, fixed BCH
341 Constant value for Galois field order 'm'. If 'k' is the
342 number of data bits to protect, 'm' should be chosen such
343 that (k + m*t) <= 2**m - 1.
344 Drivers should declare a default value for this symbol if
345 they select option BCH_CONST_PARAMS.
350 Constant value for error correction capability in bits 't'.
351 Drivers should declare a default value for this symbol if
352 they select option BCH_CONST_PARAMS.
355 # Textsearch support is select'ed if needed
360 config TEXTSEARCH_KMP
366 config TEXTSEARCH_FSM
375 Simple, embeddable, interval-tree. Can find the start of an
376 overlapping range in log(n) time and then iterate over all
377 overlapping nodes. The algorithm is implemented as an
382 Documentation/rbtree.txt
384 for more information.
386 config RADIX_TREE_MULTIORDER
389 config ASSOCIATIVE_ARRAY
392 Generic associative array. Can be searched and iterated over whilst
393 it is being modified. It is also reasonably quick to search and
394 modify. The algorithms are non-recursive, and the trees are highly
399 Documentation/assoc_array.txt
401 for more information.
409 config HAS_IOPORT_MAP
411 depends on HAS_IOMEM && !NO_IOPORT_MAP
421 depends on HAS_DMA && (!64BIT || ARCH_DMA_ADDR_T_64BIT)
426 depends on HAS_DMA && (!64BIT || ARCH_DMA_ADDR_T_64BIT)
429 config CHECK_SIGNATURE
432 config CPUMASK_OFFSTACK
433 bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
435 Use dynamic allocation for cpumask_var_t, instead of putting
436 them on the stack. This is a bit more expensive, but avoids
448 # This actually supports modular compilation, but the module overhead
449 # is ridiculous for the amount of code involved. Until an out-of-tree
450 # driver asks for it, we'll just link it directly it into the kernel
451 # when required. Since we're ignoring out-of-tree users, there's also
452 # no need bother prompting for a manual decision:
453 # prompt "glob_match() function"
455 This option provides a glob_match function for performing
456 simple text pattern matching. It originated in the ATA code
457 to blacklist particular drive models, but other device drivers
458 may need similar functionality.
460 All drivers in the Linux kernel tree that require this function
461 should automatically select this option. Say N unless you
462 are compiling an out-of tree driver which tells you that it
466 tristate "glob self-test on init"
469 This option enables a simple self-test of the glob_match
470 function on startup. It is primarily useful for people
471 working on the code to ensure they haven't introduced any
474 It only adds a little bit of code and slows kernel boot (or
475 module load) by a small amount, so you're welcome to play with
476 it, but you probably don't need it.
479 # Netlink attribute parsing support is select'ed if needed
485 # Generic 64-bit atomic support is selected if needed
487 config GENERIC_ATOMIC64
497 tristate "CORDIC algorithm"
499 This option provides an implementation of the CORDIC algorithm;
500 calculations are in fixed point. Module will be called cordic.
503 bool "JEDEC DDR data"
505 Data from JEDEC specs for DDR SDRAM memories,
506 particularly the AC timing parameters and addressing
507 information. This data is useful for drivers handling
508 DDR SDRAM controllers.
511 bool "IRQ polling library"
513 Helper library to poll interrupt mitigation using polling.
519 Multiprecision maths library from GnuPG.
520 It is used to implement RSA digital signature verification,
521 which is used by IMA/EVM digital signature extension.
530 Digital signature verification. Currently only RSA is supported.
531 Implementation is done using GnuPG MPI library
534 # libfdt files, only selected if needed.
542 Enable fast lookup object identifier registry.
547 source "lib/fonts/Kconfig"
552 Provides a helper to split scatterlists into chunks, each chunk being
553 a scatterlist. This should be selected by a driver or an API which
554 whishes to split a scatterlist amongst multiple DMA channels.
559 Provides a helper to allocate chained scatterlists. This should be
560 selected by a driver or an API which whishes to allocate chained
567 config ARCH_HAS_SG_CHAIN
570 config ARCH_HAS_PMEM_API
573 config ARCH_HAS_UACCESS_FLUSHCACHE
576 config ARCH_HAS_MMIO_FLUSH
587 tristate "parman" if COMPILE_TEST