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 bool "CRC32 perform self test on init"
124 This option enables the CRC32 library functions to perform a
125 self test on initialization. The self test computes crc32_le
126 and crc32_be over byte strings with random alignment and length
127 and computes the total elapsed time and number of bytes processed.
130 prompt "CRC32 implementation"
132 default CRC32_SLICEBY8
134 This option allows a kernel builder to override the default choice
135 of CRC32 algorithm. Choose the default ("slice by 8") unless you
136 know that you need one of the others.
138 config CRC32_SLICEBY8
139 bool "Slice by 8 bytes"
141 Calculate checksum 8 bytes at a time with a clever slicing algorithm.
142 This is the fastest algorithm, but comes with a 8KiB lookup table.
143 Most modern processors have enough cache to hold this table without
146 This is the default implementation choice. Choose this one unless
147 you have a good reason not to.
149 config CRC32_SLICEBY4
150 bool "Slice by 4 bytes"
152 Calculate checksum 4 bytes at a time with a clever slicing algorithm.
153 This is a bit slower than slice by 8, but has a smaller 4KiB lookup
156 Only choose this option if you know what you are doing.
159 bool "Sarwate's Algorithm (one byte at a time)"
161 Calculate checksum a byte at a time using Sarwate's algorithm. This
162 is not particularly fast, but has a small 256 byte lookup table.
164 Only choose this option if you know what you are doing.
167 bool "Classic Algorithm (one bit at a time)"
169 Calculate checksum one bit at a time. This is VERY slow, but has
170 no lookup table. This is provided as a debugging option.
172 Only choose this option if you are debugging crc32.
177 tristate "CRC7 functions"
179 This option is provided for the case where no in-kernel-tree
180 modules require CRC7 functions, but a module built outside
181 the kernel tree does. Such modules that use library CRC7
182 functions require M here.
185 tristate "CRC32c (Castagnoli, et al) Cyclic Redundancy-Check"
189 This option is provided for the case where no in-kernel-tree
190 modules require CRC32c functions, but a module built outside the
191 kernel tree does. Such modules that use library CRC32c functions
192 require M here. See Castagnoli93.
193 Module will be libcrc32c.
196 tristate "CRC8 function"
198 This option provides CRC8 function. Drivers may select this
199 when they need to do cyclic redundancy check according CRC8
200 algorithm. Module will be called crc8.
204 depends on AUDIT && !AUDIT_ARCH
207 config AUDIT_ARCH_COMPAT_GENERIC
211 config AUDIT_COMPAT_GENERIC
213 depends on AUDIT_GENERIC && AUDIT_ARCH_COMPAT_GENERIC && COMPAT
216 config RANDOM32_SELFTEST
217 bool "PRNG perform self test on init"
220 This option enables the 32 bit PRNG library functions to perform a
221 self test on initialization.
224 # compression support is select'ed if needed
230 config 842_DECOMPRESS
244 config LZO_DECOMPRESS
250 config LZ4HC_COMPRESS
253 config LZ4_DECOMPRESS
256 source "lib/xz/Kconfig"
259 # These all provide a common interface (hence the apparent duplication with
260 # ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
262 config DECOMPRESS_GZIP
266 config DECOMPRESS_BZIP2
269 config DECOMPRESS_LZMA
276 config DECOMPRESS_LZO
277 select LZO_DECOMPRESS
280 config DECOMPRESS_LZ4
281 select LZ4_DECOMPRESS
285 # Generic allocator support is selected if needed
287 config GENERIC_ALLOCATOR
291 # reed solomon support is select'ed if needed
296 config REED_SOLOMON_ENC8
299 config REED_SOLOMON_DEC8
302 config REED_SOLOMON_ENC16
305 config REED_SOLOMON_DEC16
309 # BCH support is selected if needed
314 config BCH_CONST_PARAMS
317 Drivers may select this option to force specific constant
318 values for parameters 'm' (Galois field order) and 't'
319 (error correction capability). Those specific values must
320 be set by declaring default values for symbols BCH_CONST_M
322 Doing so will enable extra compiler optimizations,
323 improving encoding and decoding performance up to 2x for
324 usual (m,t) values (typically such that m*t < 200).
325 When this option is selected, the BCH library supports
326 only a single (m,t) configuration. This is mainly useful
327 for NAND flash board drivers requiring known, fixed BCH
334 Constant value for Galois field order 'm'. If 'k' is the
335 number of data bits to protect, 'm' should be chosen such
336 that (k + m*t) <= 2**m - 1.
337 Drivers should declare a default value for this symbol if
338 they select option BCH_CONST_PARAMS.
343 Constant value for error correction capability in bits 't'.
344 Drivers should declare a default value for this symbol if
345 they select option BCH_CONST_PARAMS.
348 # Textsearch support is select'ed if needed
353 config TEXTSEARCH_KMP
359 config TEXTSEARCH_FSM
368 Simple, embeddable, interval-tree. Can find the start of an
369 overlapping range in log(n) time and then iterate over all
370 overlapping nodes. The algorithm is implemented as an
375 Documentation/rbtree.txt
377 for more information.
379 config RADIX_TREE_MULTIORDER
382 config ASSOCIATIVE_ARRAY
385 Generic associative array. Can be searched and iterated over whilst
386 it is being modified. It is also reasonably quick to search and
387 modify. The algorithms are non-recursive, and the trees are highly
392 Documentation/assoc_array.txt
394 for more information.
402 config HAS_IOPORT_MAP
404 depends on HAS_IOMEM && !NO_IOPORT_MAP
412 config CHECK_SIGNATURE
415 config CPUMASK_OFFSTACK
416 bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
418 Use dynamic allocation for cpumask_var_t, instead of putting
419 them on the stack. This is a bit more expensive, but avoids
431 # This actually supports modular compilation, but the module overhead
432 # is ridiculous for the amount of code involved. Until an out-of-tree
433 # driver asks for it, we'll just link it directly it into the kernel
434 # when required. Since we're ignoring out-of-tree users, there's also
435 # no need bother prompting for a manual decision:
436 # prompt "glob_match() function"
438 This option provides a glob_match function for performing
439 simple text pattern matching. It originated in the ATA code
440 to blacklist particular drive models, but other device drivers
441 may need similar functionality.
443 All drivers in the Linux kernel tree that require this function
444 should automatically select this option. Say N unless you
445 are compiling an out-of tree driver which tells you that it
449 bool "glob self-test on init"
453 This option enables a simple self-test of the glob_match
454 function on startup. It is primarily useful for people
455 working on the code to ensure they haven't introduced any
458 It only adds a little bit of code and slows kernel boot (or
459 module load) by a small amount, so you're welcome to play with
460 it, but you probably don't need it.
463 # Netlink attribute parsing support is select'ed if needed
469 # Generic 64-bit atomic support is selected if needed
471 config GENERIC_ATOMIC64
481 tristate "CORDIC algorithm"
483 This option provides an implementation of the CORDIC algorithm;
484 calculations are in fixed point. Module will be called cordic.
487 bool "JEDEC DDR data"
489 Data from JEDEC specs for DDR SDRAM memories,
490 particularly the AC timing parameters and addressing
491 information. This data is useful for drivers handling
492 DDR SDRAM controllers.
495 bool "IRQ polling library"
497 Helper library to poll interrupt mitigation using polling.
503 Multiprecision maths library from GnuPG.
504 It is used to implement RSA digital signature verification,
505 which is used by IMA/EVM digital signature extension.
514 Digital signature verification. Currently only RSA is supported.
515 Implementation is done using GnuPG MPI library
518 # libfdt files, only selected if needed.
526 Enable fast lookup object identifier registry.
531 source "lib/fonts/Kconfig"
536 Provides a helper to split scatterlists into chunks, each chunk being
537 a scatterlist. This should be selected by a driver or an API which
538 whishes to split a scatterlist amongst multiple DMA channels.
543 Provides a helper to allocate chained scatterlists. This should be
544 selected by a driver or an API which whishes to allocate chained
551 config ARCH_HAS_SG_CHAIN
554 config ARCH_HAS_PMEM_API
557 config ARCH_HAS_MMIO_FLUSH