user/sven/linux.git/lib/crc/Kconfig, branch master

lib/crc: arm64: add NEON accelerated CRC64-NVMe implementation

2026-03-29T20:22:13Z

Implement an optimized CRC64 (NVMe) algorithm for ARM64 using NEON Polynomial Multiply Long (PMULL) instructions. The generic shift-and-XOR software implementation is slow, which creates a bottleneck in NVMe and other storage subsystems. The acceleration is implemented using C intrinsics () rather than raw assembly for better readability and maintainability. Key highlights of this implementation: - Uses 4KB chunking inside scoped_ksimd() to avoid preemption latency spikes on large buffers. - Pre-calculates and loads fold constants via vld1q_u64() to minimize register spilling. - Benchmarks show the break-even point against the generic implementation is around 128 bytes. The PMULL path is enabled only for len >= 128. Performance results (kunit crc_benchmark on Cortex-A72): - Generic (len=4096): ~268 MB/s - PMULL (len=4096): ~1556 MB/s (nearly 6x improvement) Signed-off-by: Demian Shulhan Link: https://lore.kernel.org/r/20260329074338.1053550-1-demyansh@gmail.com Signed-off-by: Eric Biggers

lib/crc: arm64: Drop check for CONFIG_KERNEL_MODE_NEON

2026-03-17T16:29:28Z

CONFIG_KERNEL_MODE_NEON is always enabled on arm64, and it always has been since its introduction in 2013. Given that and the fact that the usefulness of kernel-mode NEON has only been increasing over time, checking for this option in arm64-specific code is unnecessary. Remove this check from lib/crc/ to simplify the code and prevent any future bugs where e.g. code gets disabled due to a typo in this logic. Acked-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20260314175744.30620-1-ebiggers@kernel.org Signed-off-by: Eric Biggers

lib/crc: tests: Add CRC_ENABLE_ALL_FOR_KUNIT

2026-03-09T20:29:46Z

Now that crc_kunit uses the standard "depends on" pattern, enabling the full set of CRC tests is a bit difficult, mainly due to CRC7 being rarely used. Add a kconfig option to make it easier. It is visible only when KUNIT, so hopefully the extra prompt won't be too annoying. Link: https://lore.kernel.org/r/20260306033557.250499-3-ebiggers@kernel.org Signed-off-by: Eric Biggers

lib/crc: tests: Make crc_kunit test only the enabled CRC variants

2026-03-09T20:29:46Z

Like commit 4478e8eeb871 ("lib/crypto: tests: Depend on library options rather than selecting them") did with the crypto library tests, make crc_kunit depend on the code it tests rather than selecting it. This follows the standard convention for KUnit and fixes an issue where enabling KUNIT_ALL_TESTS enabled non-test code. crc_kunit does differ from the crypto library tests in that it consolidates the tests for multiple CRC variants, with 5 kconfig options, into one KUnit suite. Since depending on *all* of these kconfig options would greatly restrict the ability to enable crc_kunit, instead just depend on *any* of these options. Update crc_kunit accordingly to test only the reachable code. Alternatively we could split crc_kunit into 5 test suites. But keeping it as one is simpler for now. Fixes: e47d9b1a76ed ("lib/crc_kunit.c: add KUnit test suite for CRC library functions") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20260306033557.250499-2-ebiggers@kernel.org Signed-off-by: Eric Biggers

lib/crc: Remove ARCH_HAS_* kconfig symbols

2025-06-30T16:31:57Z

These symbols are no longer used, so remove them. Reviewed-by: "Martin K. Petersen" Acked-by: Ingo Molnar Acked-by: "Jason A. Donenfeld" Link: https://lore.kernel.org/r/20250607200454.73587-13-ebiggers@kernel.org Signed-off-by: Eric Biggers

lib/crc: x86: Migrate optimized CRC code into lib/crc/

2025-06-30T16:31:57Z

Move the x86-optimized CRC code from arch/x86/lib/crc* into its new location in lib/crc/x86/, and wire it up in the new way. This new way of organizing the CRC code eliminates the need to artificially split the code for each CRC variant into separate arch and generic modules, enabling better inlining and dead code elimination. For more details, see "lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/". Reviewed-by: "Martin K. Petersen" Acked-by: Ingo Molnar Acked-by: "Jason A. Donenfeld" Link: https://lore.kernel.org/r/20250607200454.73587-12-ebiggers@kernel.org Signed-off-by: Eric Biggers

lib/crc: sparc: Migrate optimized CRC code into lib/crc/

2025-06-30T16:31:57Z

Move the sparc-optimized CRC code from arch/sparc/lib/crc* into its new location in lib/crc/sparc/, and wire it up in the new way. This new way of organizing the CRC code eliminates the need to artificially split the code for each CRC variant into separate arch and generic modules, enabling better inlining and dead code elimination. For more details, see "lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/". Reviewed-by: "Martin K. Petersen" Acked-by: Ingo Molnar Acked-by: "Jason A. Donenfeld" Link: https://lore.kernel.org/r/20250607200454.73587-11-ebiggers@kernel.org Signed-off-by: Eric Biggers

lib/crc: s390: Migrate optimized CRC code into lib/crc/

2025-06-30T16:31:57Z

Move the s390-optimized CRC code from arch/s390/lib/crc* into its new location in lib/crc/s390/, and wire it up in the new way. This new way of organizing the CRC code eliminates the need to artificially split the code for each CRC variant into separate arch and generic modules, enabling better inlining and dead code elimination. For more details, see "lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/". Reviewed-by: "Martin K. Petersen" Acked-by: Ingo Molnar Acked-by: "Jason A. Donenfeld" Link: https://lore.kernel.org/r/20250607200454.73587-10-ebiggers@kernel.org Signed-off-by: Eric Biggers

lib/crc: riscv: Migrate optimized CRC code into lib/crc/

2025-06-30T16:31:57Z

Move the riscv-optimized CRC code from arch/riscv/lib/crc* into its new location in lib/crc/riscv/, and wire it up in the new way. This new way of organizing the CRC code eliminates the need to artificially split the code for each CRC variant into separate arch and generic modules, enabling better inlining and dead code elimination. For more details, see "lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/". Reviewed-by: "Martin K. Petersen" Acked-by: Ingo Molnar Acked-by: "Jason A. Donenfeld" Link: https://lore.kernel.org/r/20250607200454.73587-9-ebiggers@kernel.org Signed-off-by: Eric Biggers

lib/crc: powerpc: Migrate optimized CRC code into lib/crc/

2025-06-30T16:31:57Z

Move the powerpc-optimized CRC code from arch/powerpc/lib/crc* into its new location in lib/crc/powerpc/, and wire it up in the new way. This new way of organizing the CRC code eliminates the need to artificially split the code for each CRC variant into separate arch and generic modules, enabling better inlining and dead code elimination. For more details, see "lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/". Reviewed-by: "Martin K. Petersen" Acked-by: Ingo Molnar Acked-by: "Jason A. Donenfeld" Link: https://lore.kernel.org/r/20250607200454.73587-8-ebiggers@kernel.org Signed-off-by: Eric Biggers