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
52 config ARCH_USE_CMPXCHG_LOCKREF
55 config ARCH_HAS_FAST_MULTIPLIER
59 bool "Access I/O in non-MMIO mode"
62 On some platforms where no separate I/O space exists, there are I/O
63 hosts which can not be accessed in MMIO mode. Using the logical PIO
64 mechanism, the host-local I/O resource can be mapped into system
65 logic PIO space shared with MMIO hosts, such as PCI/PCIE, then the
66 system can access the I/O devices with the mapped logic PIO through
68 This way has relatively little I/O performance cost. Please make
69 sure your devices really need this configure item enabled.
74 tristate "CRC-CCITT functions"
76 This option is provided for the case where no in-kernel-tree
77 modules require CRC-CCITT functions, but a module built outside
78 the kernel tree does. Such modules that use library CRC-CCITT
79 functions require M here.
82 tristate "CRC16 functions"
84 This option is provided for the case where no in-kernel-tree
85 modules require CRC16 functions, but a module built outside
86 the kernel tree does. Such modules that use library CRC16
87 functions require M here.
90 tristate "CRC calculation for the T10 Data Integrity Field"
92 select CRYPTO_CRCT10DIF
94 This option is only needed if a module that's not in the
95 kernel tree needs to calculate CRC checks for use with the
96 SCSI data integrity subsystem.
99 tristate "CRC ITU-T V.41 functions"
101 This option is provided for the case where no in-kernel-tree
102 modules require CRC ITU-T V.41 functions, but a module built outside
103 the kernel tree does. Such modules that use library CRC ITU-T V.41
104 functions require M here.
107 tristate "CRC32/CRC32c functions"
111 This option is provided for the case where no in-kernel-tree
112 modules require CRC32/CRC32c functions, but a module built outside
113 the kernel tree does. Such modules that use library CRC32/CRC32c
114 functions require M here.
116 config CRC32_SELFTEST
117 tristate "CRC32 perform self test on init"
120 This option enables the CRC32 library functions to perform a
121 self test on initialization. The self test computes crc32_le
122 and crc32_be over byte strings with random alignment and length
123 and computes the total elapsed time and number of bytes processed.
126 prompt "CRC32 implementation"
128 default CRC32_SLICEBY8
130 This option allows a kernel builder to override the default choice
131 of CRC32 algorithm. Choose the default ("slice by 8") unless you
132 know that you need one of the others.
134 config CRC32_SLICEBY8
135 bool "Slice by 8 bytes"
137 Calculate checksum 8 bytes at a time with a clever slicing algorithm.
138 This is the fastest algorithm, but comes with a 8KiB lookup table.
139 Most modern processors have enough cache to hold this table without
142 This is the default implementation choice. Choose this one unless
143 you have a good reason not to.
145 config CRC32_SLICEBY4
146 bool "Slice by 4 bytes"
148 Calculate checksum 4 bytes at a time with a clever slicing algorithm.
149 This is a bit slower than slice by 8, but has a smaller 4KiB lookup
152 Only choose this option if you know what you are doing.
155 bool "Sarwate's Algorithm (one byte at a time)"
157 Calculate checksum a byte at a time using Sarwate's algorithm. This
158 is not particularly fast, but has a small 256 byte lookup table.
160 Only choose this option if you know what you are doing.
163 bool "Classic Algorithm (one bit at a time)"
165 Calculate checksum one bit at a time. This is VERY slow, but has
166 no lookup table. This is provided as a debugging option.
168 Only choose this option if you are debugging crc32.
173 tristate "CRC4 functions"
175 This option is provided for the case where no in-kernel-tree
176 modules require CRC4 functions, but a module built outside
177 the kernel tree does. Such modules that use library CRC4
178 functions require M here.
181 tristate "CRC7 functions"
183 This option is provided for the case where no in-kernel-tree
184 modules require CRC7 functions, but a module built outside
185 the kernel tree does. Such modules that use library CRC7
186 functions require M here.
189 tristate "CRC32c (Castagnoli, et al) Cyclic Redundancy-Check"
193 This option is provided for the case where no in-kernel-tree
194 modules require CRC32c functions, but a module built outside the
195 kernel tree does. Such modules that use library CRC32c functions
196 require M here. See Castagnoli93.
197 Module will be libcrc32c.
200 tristate "CRC8 function"
202 This option provides CRC8 function. Drivers may select this
203 when they need to do cyclic redundancy check according CRC8
204 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
267 config ZSTD_DECOMPRESS
271 source "lib/xz/Kconfig"
274 # These all provide a common interface (hence the apparent duplication with
275 # ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
277 config DECOMPRESS_GZIP
281 config DECOMPRESS_BZIP2
284 config DECOMPRESS_LZMA
291 config DECOMPRESS_LZO
292 select LZO_DECOMPRESS
295 config DECOMPRESS_LZ4
296 select LZ4_DECOMPRESS
300 # Generic allocator support is selected if needed
302 config GENERIC_ALLOCATOR
306 # reed solomon support is select'ed if needed
311 config REED_SOLOMON_ENC8
314 config REED_SOLOMON_DEC8
317 config REED_SOLOMON_ENC16
320 config REED_SOLOMON_DEC16
324 # BCH support is selected if needed
329 config BCH_CONST_PARAMS
332 Drivers may select this option to force specific constant
333 values for parameters 'm' (Galois field order) and 't'
334 (error correction capability). Those specific values must
335 be set by declaring default values for symbols BCH_CONST_M
337 Doing so will enable extra compiler optimizations,
338 improving encoding and decoding performance up to 2x for
339 usual (m,t) values (typically such that m*t < 200).
340 When this option is selected, the BCH library supports
341 only a single (m,t) configuration. This is mainly useful
342 for NAND flash board drivers requiring known, fixed BCH
349 Constant value for Galois field order 'm'. If 'k' is the
350 number of data bits to protect, 'm' should be chosen such
351 that (k + m*t) <= 2**m - 1.
352 Drivers should declare a default value for this symbol if
353 they select option BCH_CONST_PARAMS.
358 Constant value for error correction capability in bits 't'.
359 Drivers should declare a default value for this symbol if
360 they select option BCH_CONST_PARAMS.
363 # Textsearch support is select'ed if needed
368 config TEXTSEARCH_KMP
374 config TEXTSEARCH_FSM
383 Simple, embeddable, interval-tree. Can find the start of an
384 overlapping range in log(n) time and then iterate over all
385 overlapping nodes. The algorithm is implemented as an
390 Documentation/rbtree.txt
392 for more information.
394 config RADIX_TREE_MULTIORDER
397 config ASSOCIATIVE_ARRAY
400 Generic associative array. Can be searched and iterated over whilst
401 it is being modified. It is also reasonably quick to search and
402 modify. The algorithms are non-recursive, and the trees are highly
407 Documentation/assoc_array.txt
409 for more information.
417 config HAS_IOPORT_MAP
419 depends on HAS_IOMEM && !NO_IOPORT_MAP
429 depends on HAS_DMA && (!64BIT || ARCH_DMA_ADDR_T_64BIT)
434 depends on HAS_DMA && (!64BIT || ARCH_DMA_ADDR_T_64BIT)
437 config CHECK_SIGNATURE
440 config CPUMASK_OFFSTACK
441 bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
443 Use dynamic allocation for cpumask_var_t, instead of putting
444 them on the stack. This is a bit more expensive, but avoids
456 # This actually supports modular compilation, but the module overhead
457 # is ridiculous for the amount of code involved. Until an out-of-tree
458 # driver asks for it, we'll just link it directly it into the kernel
459 # when required. Since we're ignoring out-of-tree users, there's also
460 # no need bother prompting for a manual decision:
461 # prompt "glob_match() function"
463 This option provides a glob_match function for performing
464 simple text pattern matching. It originated in the ATA code
465 to blacklist particular drive models, but other device drivers
466 may need similar functionality.
468 All drivers in the Linux kernel tree that require this function
469 should automatically select this option. Say N unless you
470 are compiling an out-of tree driver which tells you that it
474 tristate "glob self-test on init"
477 This option enables a simple self-test of the glob_match
478 function on startup. It is primarily useful for people
479 working on the code to ensure they haven't introduced any
482 It only adds a little bit of code and slows kernel boot (or
483 module load) by a small amount, so you're welcome to play with
484 it, but you probably don't need it.
487 # Netlink attribute parsing support is select'ed if needed
493 # Generic 64-bit atomic support is selected if needed
495 config GENERIC_ATOMIC64
505 tristate "CORDIC algorithm"
507 This option provides an implementation of the CORDIC algorithm;
508 calculations are in fixed point. Module will be called cordic.
511 bool "JEDEC DDR data"
513 Data from JEDEC specs for DDR SDRAM memories,
514 particularly the AC timing parameters and addressing
515 information. This data is useful for drivers handling
516 DDR SDRAM controllers.
519 bool "IRQ polling library"
521 Helper library to poll interrupt mitigation using polling.
527 Multiprecision maths library from GnuPG.
528 It is used to implement RSA digital signature verification,
529 which is used by IMA/EVM digital signature extension.
538 Digital signature verification. Currently only RSA is supported.
539 Implementation is done using GnuPG MPI library
542 # libfdt files, only selected if needed.
550 Enable fast lookup object identifier registry.
555 source "lib/fonts/Kconfig"
560 Provides a helper to split scatterlists into chunks, each chunk being
561 a scatterlist. This should be selected by a driver or an API which
562 whishes to split a scatterlist amongst multiple DMA channels.
567 Provides a helper to allocate chained scatterlists. This should be
568 selected by a driver or an API which whishes to allocate chained
575 config ARCH_HAS_SG_CHAIN
578 config ARCH_HAS_PMEM_API
581 config ARCH_HAS_UACCESS_FLUSHCACHE
592 tristate "parman" if COMPILE_TEST
597 config STRING_SELFTEST
598 tristate "Test string functions"
602 config GENERIC_ASHLDI3
605 config GENERIC_ASHRDI3
608 config GENERIC_LSHRDI3
611 config GENERIC_MULDI3
614 config GENERIC_CMPDI2
617 config GENERIC_UCMPDI2