From b5ae12e0ee099e4c458f7814f0317f4e2cbf105e Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Sun, 1 Dec 2024 17:08:28 -0800 Subject: lib/crc32: expose whether the lib is really optimized at runtime Make the CRC32 library export a function crc32_optimizations() which returns flags that indicate which CRC32 functions are actually executing optimized code at runtime. This will be used to determine whether the crc32[c]-$arch shash algorithms should be registered in the crypto API. btrfs could also start using these flags instead of the hack that it currently uses where it parses the crypto_shash_driver_name. Reviewed-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20241202010844.144356-4-ebiggers@kernel.org Signed-off-by: Eric Biggers --- include/linux/crc32.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'include/linux') diff --git a/include/linux/crc32.h b/include/linux/crc32.h index 58c632533b08..e9bd40056687 100644 --- a/include/linux/crc32.h +++ b/include/linux/crc32.h @@ -37,6 +37,21 @@ static inline u32 __pure __crc32c_le(u32 crc, const u8 *p, size_t len) return crc32c_le_base(crc, p, len); } +/* + * crc32_optimizations() returns flags that indicate which CRC32 library + * functions are using architecture-specific optimizations. Unlike + * IS_ENABLED(CONFIG_CRC32_ARCH) it takes into account the different CRC32 + * variants and also whether any needed CPU features are available at runtime. + */ +#define CRC32_LE_OPTIMIZATION BIT(0) /* crc32_le() is optimized */ +#define CRC32_BE_OPTIMIZATION BIT(1) /* crc32_be() is optimized */ +#define CRC32C_OPTIMIZATION BIT(2) /* __crc32c_le() is optimized */ +#if IS_ENABLED(CONFIG_CRC32_ARCH) +u32 crc32_optimizations(void); +#else +static inline u32 crc32_optimizations(void) { return 0; } +#endif + /** * crc32_le_combine - Combine two crc32 check values into one. For two * sequences of bytes, seq1 and seq2 with lengths len1 -- cgit v1.2.3