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author | Linus Torvalds <torvalds@linux-foundation.org> | 2025-07-28 17:43:29 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2025-07-28 17:43:29 -0700 |
commit | a578dd095dfe8b56c167201d9aea43e47d27f807 (patch) | |
tree | 6d4ee6e286b92ebad6d10572af74eb15fd31973f /lib/crc/gen_crc64table.c | |
parent | 8e736a2eeaf261213b4557778e015699da1e1c8c (diff) | |
parent | 118da22eb6fbd48f896d17411f942399283d600c (diff) |
Merge tag 'crc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux
Pull CRC updates from Eric Biggers:
- Reorganize the architecture-optimized CRC code
It now lives in lib/crc/$(SRCARCH)/ rather than arch/$(SRCARCH)/lib/,
and it is no longer artificially split into separate generic and arch
modules. This allows better inlining and dead code elimination
The generic CRC code is also no longer exported, simplifying the API.
(This mirrors the similar changes to SHA-1 and SHA-2 in lib/crypto/,
which can be found in the "Crypto library updates" pull request)
- Improve crc32c() performance on newer x86_64 CPUs on long messages by
enabling the VPCLMULQDQ optimized code
- Simplify the crypto_shash wrappers for crc32_le() and crc32c()
Register just one shash algorithm for each that uses the (fully
optimized) library functions, instead of unnecessarily providing
direct access to the generic CRC code
- Remove unused and obsolete drivers for hardware CRC engines
- Remove CRC-32 combination functions that are no longer used
- Add kerneldoc for crc32_le(), crc32_be(), and crc32c()
- Convert the crc32() macro to an inline function
* tag 'crc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux: (26 commits)
lib/crc: x86/crc32c: Enable VPCLMULQDQ optimization where beneficial
lib/crc: x86: Reorganize crc-pclmul static_call initialization
lib/crc: crc64: Add include/linux/crc64.h to kernel-api.rst
lib/crc: crc32: Change crc32() from macro to inline function and remove cast
nvmem: layouts: Switch from crc32() to crc32_le()
lib/crc: crc32: Document crc32_le(), crc32_be(), and crc32c()
lib/crc: Explicitly include <linux/export.h>
lib/crc: Remove ARCH_HAS_* kconfig symbols
lib/crc: x86: Migrate optimized CRC code into lib/crc/
lib/crc: sparc: Migrate optimized CRC code into lib/crc/
lib/crc: s390: Migrate optimized CRC code into lib/crc/
lib/crc: riscv: Migrate optimized CRC code into lib/crc/
lib/crc: powerpc: Migrate optimized CRC code into lib/crc/
lib/crc: mips: Migrate optimized CRC code into lib/crc/
lib/crc: loongarch: Migrate optimized CRC code into lib/crc/
lib/crc: arm64: Migrate optimized CRC code into lib/crc/
lib/crc: arm: Migrate optimized CRC code into lib/crc/
lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/
lib/crc: Move files into lib/crc/
lib/crc32: Remove unused combination support
...
Diffstat (limited to 'lib/crc/gen_crc64table.c')
-rw-r--r-- | lib/crc/gen_crc64table.c | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/lib/crc/gen_crc64table.c b/lib/crc/gen_crc64table.c new file mode 100644 index 000000000000..f2be9f62bab7 --- /dev/null +++ b/lib/crc/gen_crc64table.c @@ -0,0 +1,88 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This host program runs at kernel build time and generates the lookup tables + * used by the generic CRC64 code. + * + * Copyright 2018 SUSE Linux. + * Author: Coly Li <colyli@suse.de> + */ +#include <inttypes.h> +#include <stdio.h> + +#define CRC64_ECMA182_POLY 0x42F0E1EBA9EA3693ULL +#define CRC64_NVME_POLY 0x9A6C9329AC4BC9B5ULL + +static uint64_t crc64_table[256] = {0}; +static uint64_t crc64_nvme_table[256] = {0}; + +static void generate_reflected_crc64_table(uint64_t table[256], uint64_t poly) +{ + uint64_t i, j, c, crc; + + for (i = 0; i < 256; i++) { + crc = 0ULL; + c = i; + + for (j = 0; j < 8; j++) { + if ((crc ^ (c >> j)) & 1) + crc = (crc >> 1) ^ poly; + else + crc >>= 1; + } + table[i] = crc; + } +} + +static void generate_crc64_table(uint64_t table[256], uint64_t poly) +{ + uint64_t i, j, c, crc; + + for (i = 0; i < 256; i++) { + crc = 0; + c = i << 56; + + for (j = 0; j < 8; j++) { + if ((crc ^ c) & 0x8000000000000000ULL) + crc = (crc << 1) ^ poly; + else + crc <<= 1; + c <<= 1; + } + + table[i] = crc; + } +} + +static void output_table(uint64_t table[256]) +{ + int i; + + for (i = 0; i < 256; i++) { + printf("\t0x%016" PRIx64 "ULL", table[i]); + if (i & 0x1) + printf(",\n"); + else + printf(", "); + } + printf("};\n"); +} + +static void print_crc64_tables(void) +{ + printf("/* this file is generated - do not edit */\n\n"); + printf("#include <linux/types.h>\n"); + printf("#include <linux/cache.h>\n\n"); + printf("static const u64 ____cacheline_aligned crc64table[256] = {\n"); + output_table(crc64_table); + + printf("\nstatic const u64 ____cacheline_aligned crc64nvmetable[256] = {\n"); + output_table(crc64_nvme_table); +} + +int main(int argc, char *argv[]) +{ + generate_crc64_table(crc64_table, CRC64_ECMA182_POLY); + generate_reflected_crc64_table(crc64_nvme_table, CRC64_NVME_POLY); + print_crc64_tables(); + return 0; +} |