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lib: add rocksoft model crc64

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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>
This commit is contained in:
Keith Busch 2022-03-03 12:13:09 -08:00 committed by Jens Axboe
parent 7ee8809df9
commit cbc0a40e17
3 changed files with 70 additions and 11 deletions
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2
include/linux/crc64.h
View File

@ -8,4 +8,6 @@
#include <linux/types.h>
u64 __pure crc64_be(u64 crc, const void *p, size_t len);
u64 __pure crc64_rocksoft_generic(u64 crc, const void *p, size_t len);
#endif /* _LINUX_CRC64_H */

28
lib/crc64.c
View File

@ -22,6 +22,13 @@
* x^24 + x^23 + x^22 + x^21 + x^19 + x^17 + x^13 + x^12 + x^10 + x^9 +
* x^7 + x^4 + x + 1
*
* crc64rocksoft[256] table is from the Rocksoft specification polynomial
* defined as,
*
* x^64 + x^63 + x^61 + x^59 + x^58 + x^56 + x^55 + x^52 + x^49 + x^48 + x^47 +
* x^46 + x^44 + x^41 + x^37 + x^36 + x^34 + x^32 + x^31 + x^28 + x^26 + x^23 +
* x^22 + x^19 + x^16 + x^13 + x^12 + x^10 + x^9 + x^6 + x^4 + x^3 + 1
*
* Copyright 2018 SUSE Linux.
* Author: Coly Li <colyli@suse.de>
*/
@ -55,3 +62,24 @@ u64 __pure crc64_be(u64 crc, const void *p, size_t len)
return crc;
}
EXPORT_SYMBOL_GPL(crc64_be);
/**
* crc64_rocksoft_generic - Calculate bitwise Rocksoft CRC64
* @crc: seed value for computation. 0 for a new CRC calculation, or the
* previous crc64 value if computing incrementally.
* @p: pointer to buffer over which CRC64 is run
* @len: length of buffer @p
*/
u64 __pure crc64_rocksoft_generic(u64 crc, const void *p, size_t len)
{
const unsigned char *_p = p;
size_t i;
crc = ~crc;
for (i = 0; i < len; i++)
crc = (crc >> 8) ^ crc64rocksofttable[(crc & 0xff) ^ *_p++];
return ~crc;
}
EXPORT_SYMBOL_GPL(crc64_rocksoft_generic);

51
lib/gen_crc64table.c
View File

@ -17,10 +17,30 @@
#include <stdio.h>
#define CRC64_ECMA182_POLY 0x42F0E1EBA9EA3693ULL
#define CRC64_ROCKSOFT_POLY 0x9A6C9329AC4BC9B5ULL
static uint64_t crc64_table[256] = {0};
static uint64_t crc64_rocksoft_table[256] = {0};
static void generate_crc64_table(void)
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;
@ -30,26 +50,22 @@ static void generate_crc64_table(void)
for (j = 0; j < 8; j++) {
if ((crc ^ c) & 0x8000000000000000ULL)
crc = (crc << 1) ^ CRC64_ECMA182_POLY;
crc = (crc << 1) ^ poly;
else
crc <<= 1;
c <<= 1;
}
crc64_table[i] = crc;
table[i] = crc;
}
}
static void print_crc64_table(void)
static void output_table(uint64_t table[256])
{
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]);
printf("\t0x%016" PRIx64 "ULL", table[i]);
if (i & 0x1)
printf(",\n");
else
@ -58,9 +74,22 @@ static void print_crc64_table(void)
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 crc64rocksofttable[256] = {\n");
output_table(crc64_rocksoft_table);
}
int main(int argc, char *argv[])
{
generate_crc64_table();
print_crc64_table();
generate_crc64_table(crc64_table, CRC64_ECMA182_POLY);
generate_reflected_crc64_table(crc64_rocksoft_table, CRC64_ROCKSOFT_POLY);
print_crc64_tables();
return 0;
}