kernel/git/stable/linux-stable.git/lib/crc32.c, branch linux-6.14.y

lib/crc32: remove other generic implementations

2025-01-29T17:10:35+00:00

Now that we've standardized on the byte-by-byte implementation of CRC32 as the only generic implementation (see previous commit for the rationale), remove the code for the other implementations. Tested with crc_kunit. Link: https://lore.kernel.org/r/20250123212904.118683-3-ebiggers@kernel.org Reviewed-by: Ard Biesheuvel Reviewed-by: Martin K. Petersen Signed-off-by: Eric Biggers

lib/crc32: improve support for arch-specific overrides

2024-12-02T01:23:01+00:00

Currently the CRC32 library functions are defined as weak symbols, and the arm64 and riscv architectures override them. This method of arch-specific overrides has the limitation that it only works when both the base and arch code is built-in. Also, it makes the arch-specific code be silently not used if it is accidentally built with lib-y instead of obj-y; unfortunately the RISC-V code does this. This commit reorganizes the code to have explicit *_arch() functions that are called when they are enabled, similar to how some of the crypto library code works (e.g. chacha_crypt() calls chacha_crypt_arch()). Make the existing kconfig choice for the CRC32 implementation also control whether the arch-optimized implementation (if one is available) is enabled or not. Make it enabled by default if CRC32 is also enabled. The result is that arch-optimized CRC32 library functions will be included automatically when appropriate, but it is now possible to disable them. They can also now be built as a loadable module if the CRC32 library functions happen to be used only by loadable modules, in which case the arch and base CRC32 modules will be automatically loaded via direct symbol dependency when appropriate. Reviewed-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20241202010844.144356-3-ebiggers@kernel.org Signed-off-by: Eric Biggers

lib/crc32: drop leading underscores from __crc32c_le_base

2024-12-02T01:23:01+00:00

Remove the leading underscores from __crc32c_le_base(). This is in preparation for adding crc32c_le_arch() and eventually renaming __crc32c_le() to crc32c_le(). Reviewed-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20241202010844.144356-2-ebiggers@kernel.org Signed-off-by: Eric Biggers

crypto: crc32c - Provide crc32c-arch driver for accelerated library code

2024-10-28T10:33:10+00:00

crc32c-generic is currently backed by the architecture's CRC-32c library code, which may offer a variety of implementations depending on the capabilities of the platform. These are not covered by the crypto subsystem's fuzz testing capabilities because crc32c-generic is the reference driver that the fuzzing logic uses as a source of truth. Fix this by providing a crc32c-arch implementation which is based on the arch library code if available, and modify crc32c-generic so it is always based on the generic C implementation. If the arch has no CRC-32c library code, this change does nothing. Signed-off-by: Ard Biesheuvel Signed-off-by: Herbert Xu

crypto: crc32 - Provide crc32-arch driver for accelerated library code

2024-10-28T10:33:10+00:00

crc32-generic is currently backed by the architecture's CRC-32 library code, which may offer a variety of implementations depending on the capabilities of the platform. These are not covered by the crypto subsystem's fuzz testing capabilities because crc32-generic is the reference driver that the fuzzing logic uses as a source of truth. Fix this by providing a crc32-arch implementation which is based on the arch library code if available, and modify crc32-generic so it is always based on the generic C implementation. If the arch has no CRC-32 library code, this change does nothing. Signed-off-by: Ard Biesheuvel Signed-off-by: Herbert Xu

lib/crc32: Make crc32_be weak for arch override

2022-01-31T00:21:43+00:00

crc32_le and __crc32c_le can be overridden - extend this to crc32_be. Signed-off-by: Kevin Bracey Signed-off-by: Herbert Xu

lib/crc32: remove unneeded casts

2022-01-31T00:21:43+00:00

Casts were added in commit 8f243af42ade ("sections: fix const sections for crc32 table") to cope with the tables not being const. They are no longer required since commit f5e38b9284e1 ("lib: crc32: constify crc32 lookup table"). Signed-off-by: Kevin Bracey Signed-off-by: Herbert Xu

lib/crc32.c: fix trivial typo in preprocessor condition

2020-10-16T18:11:20+00:00

Whether crc32_be needs a lookup table is chosen based on CRC_LE_BITS. Obviously, the _be function should be governed by the _BE_ define. This probably never pops up as it's hard to come up with a configuration where CRC_BE_BITS isn't the same as CRC_LE_BITS and as nobody is using bitwise CRC anyway. Fixes: 46c5801eaf86 ("crc32: bolt on crc32c") Signed-off-by: Tobias Jordan Signed-off-by: Andrew Morton Cc: Krzysztof Kozlowski Cc: Jonathan Corbet Cc: Mauro Carvalho Chehab Link: https://lkml.kernel.org/r/20200923182122.GA3338@agrajag.zerfleddert.de Signed-off-by: Linus Torvalds

docs: move remaining stuff under Documentation/*.txt to Documentation/staging

2020-06-19T20:17:05+00:00

There are several files that I was unable to find a proper place for them, and 3 ones that are still in plain old text format. Let's place those stuff behind the carpet, as we'd like to keep the root directory clean. We can later discuss and move those into better places. Signed-off-by: Mauro Carvalho Chehab Link: https://lore.kernel.org/r/11bd0d75e65a874f7c276a0aeab0fe13f3376f5f.1592203650.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet

lib/crc32.c: mark crc32_le_base/__crc32c_le_base aliases as __pure

2019-02-15T18:50:07+00:00

The upcoming GCC 9 release extends the -Wmissing-attributes warnings (enabled by -Wall) to C and aliases: it warns when particular function attributes are missing in the aliases but not in their target. In particular, it triggers here because crc32_le_base/__crc32c_le_base aren't __pure while their target crc32_le/__crc32c_le are. These aliases are used by architectures as a fallback in accelerated versions of CRC32. See commit 9784d82db3eb ("lib/crc32: make core crc32() routines weak so they can be overridden"). Therefore, being fallbacks, it is likely that even if the aliases were called from C, there wouldn't be any optimizations possible. Currently, the only user is arm64, which calls this from asm. Still, marking the aliases as __pure makes sense and is a good idea for documentation purposes and possible future optimizations, which also silences the warning. Acked-by: Ard Biesheuvel Tested-by: Laura Abbott Signed-off-by: Miguel Ojeda