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cbc0a40e17
The NVM Express specification extended data integrity fields to 64 bits
using the Rocksoft parameters. Add the poly to the crc64 table
generation, and provide a generic library routine implementing the
algorithm.
The Rocksoft 64-bit CRC model parameters are as follows:
Poly: 0xAD93D23594C93659
Initial value: 0xFFFFFFFFFFFFFFFF
Reflected Input: True
Reflected Output: True
Xor Final: 0xFFFFFFFFFFFFFFFF
Since this model used reflected bits, the implementation generates the
reflected table so the result is ordered consistently.
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20220303201312.3255347-6-kbusch@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
96 lines
2.1 KiB
C
96 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Generate lookup table for the table-driven CRC64 calculation.
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*
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* gen_crc64table is executed in kernel build time and generates
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* lib/crc64table.h. This header is included by lib/crc64.c for
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* the table-driven CRC64 calculation.
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*
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* See lib/crc64.c for more information about which specification
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* and polynomial arithmetic that gen_crc64table.c follows to
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* generate the lookup table.
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*
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* Copyright 2018 SUSE Linux.
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* Author: Coly Li <colyli@suse.de>
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*/
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#include <inttypes.h>
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#include <stdio.h>
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#define CRC64_ECMA182_POLY 0x42F0E1EBA9EA3693ULL
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#define CRC64_ROCKSOFT_POLY 0x9A6C9329AC4BC9B5ULL
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static uint64_t crc64_table[256] = {0};
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static uint64_t crc64_rocksoft_table[256] = {0};
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static void generate_reflected_crc64_table(uint64_t table[256], uint64_t poly)
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{
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uint64_t i, j, c, crc;
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for (i = 0; i < 256; i++) {
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crc = 0ULL;
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c = i;
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for (j = 0; j < 8; j++) {
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if ((crc ^ (c >> j)) & 1)
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crc = (crc >> 1) ^ poly;
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else
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crc >>= 1;
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}
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table[i] = crc;
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}
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}
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static void generate_crc64_table(uint64_t table[256], uint64_t poly)
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{
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uint64_t i, j, c, crc;
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for (i = 0; i < 256; i++) {
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crc = 0;
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c = i << 56;
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for (j = 0; j < 8; j++) {
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if ((crc ^ c) & 0x8000000000000000ULL)
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crc = (crc << 1) ^ poly;
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else
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crc <<= 1;
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c <<= 1;
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}
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table[i] = crc;
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}
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}
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static void output_table(uint64_t table[256])
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{
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int i;
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for (i = 0; i < 256; i++) {
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printf("\t0x%016" PRIx64 "ULL", table[i]);
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if (i & 0x1)
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printf(",\n");
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else
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printf(", ");
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}
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printf("};\n");
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}
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static void print_crc64_tables(void)
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{
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printf("/* this file is generated - do not edit */\n\n");
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printf("#include <linux/types.h>\n");
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printf("#include <linux/cache.h>\n\n");
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printf("static const u64 ____cacheline_aligned crc64table[256] = {\n");
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output_table(crc64_table);
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printf("\nstatic const u64 ____cacheline_aligned crc64rocksofttable[256] = {\n");
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output_table(crc64_rocksoft_table);
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}
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int main(int argc, char *argv[])
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{
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generate_crc64_table(crc64_table, CRC64_ECMA182_POLY);
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generate_reflected_crc64_table(crc64_rocksoft_table, CRC64_ROCKSOFT_POLY);
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print_crc64_tables();
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return 0;
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}
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