1 # SPDX-License-Identifier: GPL-2.0-only
3 # Library configuration
9 menu "Library routines"
14 config RAID6_PQ_BENCHMARK
15 bool "Automatically choose fastest RAID6 PQ functions"
19 Benchmark all available RAID6 PQ functions on init and choose the
26 bool "Generic bitfield packing and unpacking"
29 This option provides the packing() helper function, which permits
30 converting bitfields between a CPU-usable representation and a
31 memory representation that can have any combination of these quirks:
32 - Is little endian (bytes are reversed within a 32-bit group)
33 - The least-significant 32-bit word comes first (within a 64-bit
35 - The most significant bit of a byte is at its right (bit 0 of a
36 register description is numerically 2^7).
37 Drivers may use these helpers to match the bit indices as described
38 in the data sheets of the peripherals they are in control of.
45 config HAVE_ARCH_BITREVERSE
49 This option enables the use of hardware bit-reversal instructions on
50 architectures which support such operations.
52 config ARCH_HAS_STRNCPY_FROM_USER
55 config ARCH_HAS_STRNLEN_USER
58 config GENERIC_STRNCPY_FROM_USER
59 def_bool !ARCH_HAS_STRNCPY_FROM_USER
61 config GENERIC_STRNLEN_USER
62 def_bool !ARCH_HAS_STRNLEN_USER
64 config GENERIC_NET_UTILS
67 config GENERIC_FIND_FIRST_BIT
70 source "lib/math/Kconfig"
72 config NO_GENERIC_PCI_IOPORT_MAP
75 config GENERIC_PCI_IOMAP
80 select GENERIC_PCI_IOMAP
85 config ARCH_USE_CMPXCHG_LOCKREF
88 config ARCH_HAS_FAST_MULTIPLIER
91 config ARCH_USE_SYM_ANNOTATIONS
95 bool "Access I/O in non-MMIO mode"
98 On some platforms where no separate I/O space exists, there are I/O
99 hosts which can not be accessed in MMIO mode. Using the logical PIO
100 mechanism, the host-local I/O resource can be mapped into system
101 logic PIO space shared with MMIO hosts, such as PCI/PCIe, then the
102 system can access the I/O devices with the mapped-logic PIO through
105 This way has relatively little I/O performance cost. Please make
106 sure your devices really need this configure item enabled.
108 When in doubt, say N.
110 config INDIRECT_IOMEM
113 This is selected by other options/architectures to provide the
114 emulated iomem accessors.
116 config INDIRECT_IOMEM_FALLBACK
118 depends on INDIRECT_IOMEM
120 If INDIRECT_IOMEM is selected, this enables falling back to plain
121 mmio accesses when the IO memory address is not a registered
124 source "lib/crypto/Kconfig"
127 tristate "CRC-CCITT functions"
129 This option is provided for the case where no in-kernel-tree
130 modules require CRC-CCITT functions, but a module built outside
131 the kernel tree does. Such modules that use library CRC-CCITT
132 functions require M here.
135 tristate "CRC16 functions"
137 This option is provided for the case where no in-kernel-tree
138 modules require CRC16 functions, but a module built outside
139 the kernel tree does. Such modules that use library CRC16
140 functions require M here.
143 tristate "CRC calculation for the T10 Data Integrity Field"
145 select CRYPTO_CRCT10DIF
147 This option is only needed if a module that's not in the
148 kernel tree needs to calculate CRC checks for use with the
149 SCSI data integrity subsystem.
152 tristate "CRC ITU-T V.41 functions"
154 This option is provided for the case where no in-kernel-tree
155 modules require CRC ITU-T V.41 functions, but a module built outside
156 the kernel tree does. Such modules that use library CRC ITU-T V.41
157 functions require M here.
160 tristate "CRC32/CRC32c functions"
164 This option is provided for the case where no in-kernel-tree
165 modules require CRC32/CRC32c functions, but a module built outside
166 the kernel tree does. Such modules that use library CRC32/CRC32c
167 functions require M here.
169 config CRC32_SELFTEST
170 tristate "CRC32 perform self test on init"
173 This option enables the CRC32 library functions to perform a
174 self test on initialization. The self test computes crc32_le
175 and crc32_be over byte strings with random alignment and length
176 and computes the total elapsed time and number of bytes processed.
179 prompt "CRC32 implementation"
181 default CRC32_SLICEBY8
183 This option allows a kernel builder to override the default choice
184 of CRC32 algorithm. Choose the default ("slice by 8") unless you
185 know that you need one of the others.
187 config CRC32_SLICEBY8
188 bool "Slice by 8 bytes"
190 Calculate checksum 8 bytes at a time with a clever slicing algorithm.
191 This is the fastest algorithm, but comes with a 8KiB lookup table.
192 Most modern processors have enough cache to hold this table without
195 This is the default implementation choice. Choose this one unless
196 you have a good reason not to.
198 config CRC32_SLICEBY4
199 bool "Slice by 4 bytes"
201 Calculate checksum 4 bytes at a time with a clever slicing algorithm.
202 This is a bit slower than slice by 8, but has a smaller 4KiB lookup
205 Only choose this option if you know what you are doing.
208 bool "Sarwate's Algorithm (one byte at a time)"
210 Calculate checksum a byte at a time using Sarwate's algorithm. This
211 is not particularly fast, but has a small 256 byte lookup table.
213 Only choose this option if you know what you are doing.
216 bool "Classic Algorithm (one bit at a time)"
218 Calculate checksum one bit at a time. This is VERY slow, but has
219 no lookup table. This is provided as a debugging option.
221 Only choose this option if you are debugging crc32.
226 tristate "CRC64 functions"
228 This option is provided for the case where no in-kernel-tree
229 modules require CRC64 functions, but a module built outside
230 the kernel tree does. Such modules that use library CRC64
231 functions require M here.
234 tristate "CRC4 functions"
236 This option is provided for the case where no in-kernel-tree
237 modules require CRC4 functions, but a module built outside
238 the kernel tree does. Such modules that use library CRC4
239 functions require M here.
242 tristate "CRC7 functions"
244 This option is provided for the case where no in-kernel-tree
245 modules require CRC7 functions, but a module built outside
246 the kernel tree does. Such modules that use library CRC7
247 functions require M here.
250 tristate "CRC32c (Castagnoli, et al) Cyclic Redundancy-Check"
254 This option is provided for the case where no in-kernel-tree
255 modules require CRC32c functions, but a module built outside the
256 kernel tree does. Such modules that use library CRC32c functions
257 require M here. See Castagnoli93.
258 Module will be libcrc32c.
261 tristate "CRC8 function"
263 This option provides CRC8 function. Drivers may select this
264 when they need to do cyclic redundancy check according CRC8
265 algorithm. Module will be called crc8.
272 depends on AUDIT && !AUDIT_ARCH
275 config AUDIT_ARCH_COMPAT_GENERIC
279 config AUDIT_COMPAT_GENERIC
281 depends on AUDIT_GENERIC && AUDIT_ARCH_COMPAT_GENERIC && COMPAT
284 config RANDOM32_SELFTEST
285 bool "PRNG perform self test on init"
287 This option enables the 32 bit PRNG library functions to perform a
288 self test on initialization.
291 # compression support is select'ed if needed
297 config 842_DECOMPRESS
311 prompt "Enable s390x DEFLATE CONVERSION CALL support for kernel zlib"
313 Enable s390x hardware support for zlib in the kernel.
318 config LZO_DECOMPRESS
324 config LZ4HC_COMPRESS
327 config LZ4_DECOMPRESS
334 config ZSTD_DECOMPRESS
338 source "lib/xz/Kconfig"
341 # These all provide a common interface (hence the apparent duplication with
342 # ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
344 config DECOMPRESS_GZIP
348 config DECOMPRESS_BZIP2
351 config DECOMPRESS_LZMA
358 config DECOMPRESS_LZO
359 select LZO_DECOMPRESS
362 config DECOMPRESS_LZ4
363 select LZ4_DECOMPRESS
366 config DECOMPRESS_ZSTD
367 select ZSTD_DECOMPRESS
371 # Generic allocator support is selected if needed
373 config GENERIC_ALLOCATOR
377 # reed solomon support is select'ed if needed
382 config REED_SOLOMON_ENC8
385 config REED_SOLOMON_DEC8
388 config REED_SOLOMON_ENC16
391 config REED_SOLOMON_DEC16
395 # BCH support is selected if needed
400 config BCH_CONST_PARAMS
403 Drivers may select this option to force specific constant
404 values for parameters 'm' (Galois field order) and 't'
405 (error correction capability). Those specific values must
406 be set by declaring default values for symbols BCH_CONST_M
408 Doing so will enable extra compiler optimizations,
409 improving encoding and decoding performance up to 2x for
410 usual (m,t) values (typically such that m*t < 200).
411 When this option is selected, the BCH library supports
412 only a single (m,t) configuration. This is mainly useful
413 for NAND flash board drivers requiring known, fixed BCH
420 Constant value for Galois field order 'm'. If 'k' is the
421 number of data bits to protect, 'm' should be chosen such
422 that (k + m*t) <= 2**m - 1.
423 Drivers should declare a default value for this symbol if
424 they select option BCH_CONST_PARAMS.
429 Constant value for error correction capability in bits 't'.
430 Drivers should declare a default value for this symbol if
431 they select option BCH_CONST_PARAMS.
434 # Textsearch support is select'ed if needed
439 config TEXTSEARCH_KMP
445 config TEXTSEARCH_FSM
454 Simple, embeddable, interval-tree. Can find the start of an
455 overlapping range in log(n) time and then iterate over all
456 overlapping nodes. The algorithm is implemented as an
461 Documentation/core-api/rbtree.rst
463 for more information.
468 Support entries which occupy multiple consecutive indices in the
471 config ASSOCIATIVE_ARRAY
474 Generic associative array. Can be searched and iterated over whilst
475 it is being modified. It is also reasonably quick to search and
476 modify. The algorithms are non-recursive, and the trees are highly
481 Documentation/core-api/assoc_array.rst
483 for more information.
490 config HAS_IOPORT_MAP
492 depends on HAS_IOMEM && !NO_IOPORT_MAP
495 source "kernel/dma/Kconfig"
504 config CHECK_SIGNATURE
507 config CPUMASK_OFFSTACK
508 bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
510 Use dynamic allocation for cpumask_var_t, instead of putting
511 them on the stack. This is a bit more expensive, but avoids
523 # This actually supports modular compilation, but the module overhead
524 # is ridiculous for the amount of code involved. Until an out-of-tree
525 # driver asks for it, we'll just link it directly it into the kernel
526 # when required. Since we're ignoring out-of-tree users, there's also
527 # no need bother prompting for a manual decision:
528 # prompt "glob_match() function"
530 This option provides a glob_match function for performing
531 simple text pattern matching. It originated in the ATA code
532 to blacklist particular drive models, but other device drivers
533 may need similar functionality.
535 All drivers in the Linux kernel tree that require this function
536 should automatically select this option. Say N unless you
537 are compiling an out-of tree driver which tells you that it
541 tristate "glob self-test on init"
544 This option enables a simple self-test of the glob_match
545 function on startup. It is primarily useful for people
546 working on the code to ensure they haven't introduced any
549 It only adds a little bit of code and slows kernel boot (or
550 module load) by a small amount, so you're welcome to play with
551 it, but you probably don't need it.
554 # Netlink attribute parsing support is select'ed if needed
560 # Generic 64-bit atomic support is selected if needed
562 config GENERIC_ATOMIC64
572 bool "IRQ polling library"
574 Helper library to poll interrupt mitigation using polling.
580 Multiprecision maths library from GnuPG.
581 It is used to implement RSA digital signature verification,
582 which is used by IMA/EVM digital signature extension.
591 Digital signature verification. Currently only RSA is supported.
592 Implementation is done using GnuPG MPI library
597 Dynamic Interrupt Moderation library.
598 Implements an algorithm for dynamically changing CQ moderation values
599 according to run time performance.
602 # libfdt files, only selected if needed.
610 Enable fast lookup object identifier registry.
618 source "lib/vdso/Kconfig"
620 source "lib/fonts/Kconfig"
625 Provides a helper to split scatterlists into chunks, each chunk being
626 a scatterlist. This should be selected by a driver or an API which
627 whishes to split a scatterlist amongst multiple DMA channels.
632 Provides a helper to allocate chained scatterlists. This should be
633 selected by a driver or an API which whishes to allocate chained
640 config ARCH_NO_SG_CHAIN
643 config ARCH_HAS_PMEM_API
649 config ARCH_HAS_MEMREMAP_COMPAT_ALIGN
652 # use memcpy to implement user copies for nommu architectures
653 config UACCESS_MEMCPY
656 config ARCH_HAS_UACCESS_FLUSHCACHE
659 # arch has a concept of a recoverable synchronous exception due to a
660 # memory-read error like x86 machine-check or ARM data-abort, and
661 # implements copy_mc_to_{user,kernel} to abort and report
662 # 'bytes-transferred' if that exception fires when accessing the source
664 config ARCH_HAS_COPY_MC
667 # Temporary. Goes away when all archs are cleaned up
668 config ARCH_STACKWALK
675 config STACK_HASH_ORDER
676 int "stack depot hash size (12 => 4KB, 20 => 1024KB)"
679 depends on STACKDEPOT
681 Select the hash size as a power of 2 for the stackdepot hash table.
682 Choose a lower value to reduce the memory impact.
688 tristate "parman" if COMPILE_TEST
691 tristate "objagg" if COMPILE_TEST
695 config GENERIC_IOREMAP
698 config GENERIC_LIB_ASHLDI3
701 config GENERIC_LIB_ASHRDI3
704 config GENERIC_LIB_LSHRDI3
707 config GENERIC_LIB_MULDI3
710 config GENERIC_LIB_CMPDI2
713 config GENERIC_LIB_UCMPDI2
716 config GENERIC_LIB_DEVMEM_IS_ALLOWED