kernel/linux.git/lib/crc/arm, branch v7.2-rc1

lib/crc: arm: Enable arm64's NEON intrinsics implementation of crc64

2026-05-28T20:14:23+00:00

Tweak the NEON intrinsics crc64 code written for arm64 so it can be built for 32-bit ARM as well. The only workaround needed is to provide alternatives for vmull_p64() and vmull_high_p64() on Clang, which only defines those when building for the AArch64 or arm64ec ISA. Use the same helpers for GCC too, to avoid doubling the size of the test/validation matrix. KUnit benchmark results (Cortex-A53 @ 1 Ghz) Before: # crc64_nvme_benchmark: len=1: 35 MB/s # crc64_nvme_benchmark: len=16: 78 MB/s # crc64_nvme_benchmark: len=64: 87 MB/s # crc64_nvme_benchmark: len=127: 88 MB/s # crc64_nvme_benchmark: len=128: 88 MB/s # crc64_nvme_benchmark: len=200: 89 MB/s # crc64_nvme_benchmark: len=256: 89 MB/s # crc64_nvme_benchmark: len=511: 89 MB/s # crc64_nvme_benchmark: len=512: 89 MB/s # crc64_nvme_benchmark: len=1024: 90 MB/s # crc64_nvme_benchmark: len=3173: 90 MB/s # crc64_nvme_benchmark: len=4096: 90 MB/s # crc64_nvme_benchmark: len=16384: 90 MB/s After: # crc64_nvme_benchmark: len=1: 32 MB/s # crc64_nvme_benchmark: len=16: 76 MB/s # crc64_nvme_benchmark: len=64: 71 MB/s # crc64_nvme_benchmark: len=127: 88 MB/s # crc64_nvme_benchmark: len=128: 618 MB/s # crc64_nvme_benchmark: len=200: 542 MB/s # crc64_nvme_benchmark: len=256: 920 MB/s # crc64_nvme_benchmark: len=511: 836 MB/s # crc64_nvme_benchmark: len=512: 1261 MB/s # crc64_nvme_benchmark: len=1024: 1531 MB/s # crc64_nvme_benchmark: len=3173: 1731 MB/s # crc64_nvme_benchmark: len=4096: 1851 MB/s # crc64_nvme_benchmark: len=16384: 1858 MB/s Don't bother with big-endian, as it doesn't work correctly on Clang, and is barely used these days. Note that ARM disables preemption and softirq processing when using kernel mode SIMD, so take care not to hog the CPU for too long. Signed-off-by: Ard Biesheuvel Link: https://patch.msgid.link/20260422171655.3437334-15-ardb+git@google.com Signed-off-by: Eric Biggers

lib/crc: Switch ARM and arm64 to 'ksimd' scoped guard API

2025-11-12T08:52:01+00:00

Before modifying the prototypes of kernel_neon_begin() and kernel_neon_end() to accommodate kernel mode FP/SIMD state buffers allocated on the stack, move arm64 to the new 'ksimd' scoped guard API, which encapsulates the calls to those functions. For symmetry, do the same for 32-bit ARM too. Reviewed-by: Eric Biggers Reviewed-by: Jonathan Cameron Acked-by: Catalin Marinas Signed-off-by: Ard Biesheuvel

lib/crc: Drop inline from all *_mod_init_arch() functions

2025-08-16T02:06:08+00:00

Drop 'inline' from all the *_mod_init_arch() functions so that the compiler will warn about any bugs where they are unused due to not being wired up properly. (There are no such bugs currently, so this just establishes a more robust convention for the future. Of course, these functions also tend to get inlined anyway, regardless of the keyword.) Link: https://lore.kernel.org/r/20250816020240.431545-1-ebiggers@kernel.org Signed-off-by: Eric Biggers

lib/crc: Use underlying functions instead of crypto_simd_usable()

2025-08-11T18:28:00+00:00

Since crc_kunit now tests the fallback code paths without using crypto_simd_disabled_for_test, make the CRC code just use the underlying may_use_simd() and irq_fpu_usable() functions directly instead of crypto_simd_usable(). This eliminates an unnecessary layer. Take the opportunity to add likely() and unlikely() annotations as well. Link: https://lore.kernel.org/r/20250811182631.376302-4-ebiggers@kernel.org Signed-off-by: Eric Biggers

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

2025-06-30T16:31:57+00:00

Move the arm-optimized CRC code from arch/arm/lib/crc* into its new location in lib/crc/arm/, 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/20250607200454.73587-4-ebiggers@kernel.org Signed-off-by: Eric Biggers