// SPDX-License-Identifier: GPL-2.0 /* * Generate lookup table for the table-driven CRC64 calculation. * * gen_crc64table is executed in kernel build time and generates * lib/crc64table.h. This header is included by lib/crc64.c for * the table-driven CRC64 calculation. * * See lib/crc64.c for more information about which specification * and polynomial arithmetic that gen_crc64table.c follows to * generate the lookup table. * * Copyright 2018 SUSE Linux. * Author: Coly Li <colyli@suse.de> */ #include <inttypes.h> #include <stdio.h> #define CRC64_ECMA182_POLY 0x42F0E1EBA9EA3693ULL static uint64_t crc64_table[256] = {0}; static void generate_crc64_table(void) { 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) ^ CRC64_ECMA182_POLY; else crc <<= 1; c <<= 1; } crc64_table[i] = crc; } } static void print_crc64_table(void) { int i; 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"); for (i = 0; i < 256; i++) { printf("\t0x%016" PRIx64 "ULL", crc64_table[i]); if (i & 0x1) printf(",\n"); else printf(", "); } printf("};\n"); } int main(int argc, char *argv[]) { generate_crc64_table(); print_crc64_table(); return 0; }