Coly Li | feba04f | 2018-08-21 21:57:11 -0700 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * Generate lookup table for the table-driven CRC64 calculation. |
| 4 | * |
| 5 | * gen_crc64table is executed in kernel build time and generates |
| 6 | * lib/crc64table.h. This header is included by lib/crc64.c for |
| 7 | * the table-driven CRC64 calculation. |
| 8 | * |
| 9 | * See lib/crc64.c for more information about which specification |
| 10 | * and polynomial arithmetic that gen_crc64table.c follows to |
| 11 | * generate the lookup table. |
| 12 | * |
| 13 | * Copyright 2018 SUSE Linux. |
| 14 | * Author: Coly Li <colyli@suse.de> |
| 15 | */ |
| 16 | #include <inttypes.h> |
| 17 | #include <stdio.h> |
| 18 | |
Coly Li | feba04f | 2018-08-21 21:57:11 -0700 | [diff] [blame] | 19 | #define CRC64_ECMA182_POLY 0x42F0E1EBA9EA3693ULL |
Keith Busch | cbc0a40 | 2022-03-03 12:13:09 -0800 | [diff] [blame] | 20 | #define CRC64_ROCKSOFT_POLY 0x9A6C9329AC4BC9B5ULL |
Coly Li | feba04f | 2018-08-21 21:57:11 -0700 | [diff] [blame] | 21 | |
| 22 | static uint64_t crc64_table[256] = {0}; |
Keith Busch | cbc0a40 | 2022-03-03 12:13:09 -0800 | [diff] [blame] | 23 | static uint64_t crc64_rocksoft_table[256] = {0}; |
Coly Li | feba04f | 2018-08-21 21:57:11 -0700 | [diff] [blame] | 24 | |
Keith Busch | cbc0a40 | 2022-03-03 12:13:09 -0800 | [diff] [blame] | 25 | static void generate_reflected_crc64_table(uint64_t table[256], uint64_t poly) |
| 26 | { |
| 27 | uint64_t i, j, c, crc; |
| 28 | |
| 29 | for (i = 0; i < 256; i++) { |
| 30 | crc = 0ULL; |
| 31 | c = i; |
| 32 | |
| 33 | for (j = 0; j < 8; j++) { |
| 34 | if ((crc ^ (c >> j)) & 1) |
| 35 | crc = (crc >> 1) ^ poly; |
| 36 | else |
| 37 | crc >>= 1; |
| 38 | } |
| 39 | table[i] = crc; |
| 40 | } |
| 41 | } |
| 42 | |
| 43 | static void generate_crc64_table(uint64_t table[256], uint64_t poly) |
Coly Li | feba04f | 2018-08-21 21:57:11 -0700 | [diff] [blame] | 44 | { |
| 45 | uint64_t i, j, c, crc; |
| 46 | |
| 47 | for (i = 0; i < 256; i++) { |
| 48 | crc = 0; |
| 49 | c = i << 56; |
| 50 | |
| 51 | for (j = 0; j < 8; j++) { |
| 52 | if ((crc ^ c) & 0x8000000000000000ULL) |
Keith Busch | cbc0a40 | 2022-03-03 12:13:09 -0800 | [diff] [blame] | 53 | crc = (crc << 1) ^ poly; |
Coly Li | feba04f | 2018-08-21 21:57:11 -0700 | [diff] [blame] | 54 | else |
| 55 | crc <<= 1; |
| 56 | c <<= 1; |
| 57 | } |
| 58 | |
Keith Busch | cbc0a40 | 2022-03-03 12:13:09 -0800 | [diff] [blame] | 59 | table[i] = crc; |
Coly Li | feba04f | 2018-08-21 21:57:11 -0700 | [diff] [blame] | 60 | } |
| 61 | } |
| 62 | |
Keith Busch | cbc0a40 | 2022-03-03 12:13:09 -0800 | [diff] [blame] | 63 | static void output_table(uint64_t table[256]) |
Coly Li | feba04f | 2018-08-21 21:57:11 -0700 | [diff] [blame] | 64 | { |
| 65 | int i; |
| 66 | |
Coly Li | feba04f | 2018-08-21 21:57:11 -0700 | [diff] [blame] | 67 | for (i = 0; i < 256; i++) { |
Keith Busch | cbc0a40 | 2022-03-03 12:13:09 -0800 | [diff] [blame] | 68 | printf("\t0x%016" PRIx64 "ULL", table[i]); |
Coly Li | feba04f | 2018-08-21 21:57:11 -0700 | [diff] [blame] | 69 | if (i & 0x1) |
| 70 | printf(",\n"); |
| 71 | else |
| 72 | printf(", "); |
| 73 | } |
| 74 | printf("};\n"); |
| 75 | } |
| 76 | |
Keith Busch | cbc0a40 | 2022-03-03 12:13:09 -0800 | [diff] [blame] | 77 | static void print_crc64_tables(void) |
| 78 | { |
| 79 | printf("/* this file is generated - do not edit */\n\n"); |
| 80 | printf("#include <linux/types.h>\n"); |
| 81 | printf("#include <linux/cache.h>\n\n"); |
| 82 | printf("static const u64 ____cacheline_aligned crc64table[256] = {\n"); |
| 83 | output_table(crc64_table); |
| 84 | |
| 85 | printf("\nstatic const u64 ____cacheline_aligned crc64rocksofttable[256] = {\n"); |
| 86 | output_table(crc64_rocksoft_table); |
| 87 | } |
| 88 | |
Coly Li | feba04f | 2018-08-21 21:57:11 -0700 | [diff] [blame] | 89 | int main(int argc, char *argv[]) |
| 90 | { |
Keith Busch | cbc0a40 | 2022-03-03 12:13:09 -0800 | [diff] [blame] | 91 | generate_crc64_table(crc64_table, CRC64_ECMA182_POLY); |
| 92 | generate_reflected_crc64_table(crc64_rocksoft_table, CRC64_ROCKSOFT_POLY); |
| 93 | print_crc64_tables(); |
Coly Li | feba04f | 2018-08-21 21:57:11 -0700 | [diff] [blame] | 94 | return 0; |
| 95 | } |