lib: add rocksoft model crc64

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.

Keith Busch committed 4 years ago

Commit cbc0a401 parent 7ee88093 files · +70 −11Browse files

Unified · Split

3 files

include/linux/crc64.h +2 −0
lib/crc64.c +28 −0
lib/gen_crc64table.c +40 −11

include/linux/crc64.h+2−0

@@ -8,4 +8,6 @@ · 7 unmodified lines
8	8	#include <linux/types.h>
9	9
10	10	u64 __pure crc64_be(u64 crc, const void *p, size_t len);
	11	+u64 __pure crc64_rocksoft_generic(u64 crc, const void *p, size_t len);
	12	+
11	13	#endif /* _LINUX_CRC64_H */

lib/crc64.c+28−0

@@ -22,6 +22,13 @@ · 21 unmodified lines
22	22	* x^24 + x^23 + x^22 + x^21 + x^19 + x^17 + x^13 + x^12 + x^10 + x^9 +
23	23	* x^7 + x^4 + x + 1
24	24	*
	25	+ * crc64rocksoft[256] table is from the Rocksoft specification polynomial
	26	+ * defined as,
	27	+ *
	28	+ * x^64 + x^63 + x^61 + x^59 + x^58 + x^56 + x^55 + x^52 + x^49 + x^48 + x^47 +
	29	+ * x^46 + x^44 + x^41 + x^37 + x^36 + x^34 + x^32 + x^31 + x^28 + x^26 + x^23 +
	30	+ * x^22 + x^19 + x^16 + x^13 + x^12 + x^10 + x^9 + x^6 + x^4 + x^3 + 1
	31	+ *
25	32	* Copyright 2018 SUSE Linux.
26	33	* Author: Coly Li <colyli@suse.de>
27	34	*/
@@ -55,3 +62,24 @@ u64 __pure crc64_be(u64 crc, const void *p, size_t len) · 27 unmodified lines
55	62	return crc;
56	63	}
57	64	EXPORT_SYMBOL_GPL(crc64_be);
	65	+
	66	+/**
	67	+ * crc64_rocksoft_generic - Calculate bitwise Rocksoft CRC64
	68	+ * @crc: seed value for computation. 0 for a new CRC calculation, or the
	69	+ * previous crc64 value if computing incrementally.
	70	+ * @p: pointer to buffer over which CRC64 is run
	71	+ * @len: length of buffer @p
	72	+ */
	73	+u64 __pure crc64_rocksoft_generic(u64 crc, const void *p, size_t len)
	74	+{
	75	+ const unsigned char *_p = p;
	76	+ size_t i;
	77	+
	78	+ crc = ~crc;
	79	+
	80	+ for (i = 0; i < len; i++)
	81	+ crc = (crc >> 8) ^ crc64rocksofttable[(crc & 0xff) ^ *_p++];
	82	+
	83	+ return ~crc;
	84	+}
	85	+EXPORT_SYMBOL_GPL(crc64_rocksoft_generic);

lib/gen_crc64table.c+40−11

@@ -17,10 +17,30 @@ · 16 unmodified lines
17	17	#include <stdio.h>
18	18
19	19	#define CRC64_ECMA182_POLY 0x42F0E1EBA9EA3693ULL
	20	+#define CRC64_ROCKSOFT_POLY 0x9A6C9329AC4BC9B5ULL
20	21
21	22	static uint64_t crc64_table[256] = {0};
	23	+static uint64_t crc64_rocksoft_table[256] = {0};
22	24
23		−static void generate_crc64_table(void)
	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)
24	44	{
25	45	uint64_t i, j, c, crc;
26	46
@@ -30,26 +50,22 @@ static void generate_crc64_table(void) · 3 unmodified lines
30	50
31	51	for (j = 0; j < 8; j++) {
32	52	if ((crc ^ c) & 0x8000000000000000ULL)
33		− crc = (crc << 1) ^ CRC64_ECMA182_POLY;
	53	+ crc = (crc << 1) ^ poly;
34	54	else
35	55	crc <<= 1;
36	56	c <<= 1;
37	57	}
38	58
39		− crc64_table[i] = crc;
	59	+ table[i] = crc;
40	60	}
41	61	}
42	62
43		−static void print_crc64_table(void)
	63	+static void output_table(uint64_t table[256])
44	64	{
45	65	int i;
46	66
47		− printf("/* this file is generated - do not edit */\n\n");
48		− printf("#include <linux/types.h>\n");
49		− printf("#include <linux/cache.h>\n\n");
50		− printf("static const u64 ____cacheline_aligned crc64table[256] = {\n");
51	67	for (i = 0; i < 256; i++) {
52		− printf("\t0x%016" PRIx64 "ULL", crc64_table[i]);
	68	+ printf("\t0x%016" PRIx64 "ULL", table[i]);
53	69	if (i & 0x1)
54	70	printf(",\n");
55	71	else
@@ -58,9 +74,22 @@ static void print_crc64_table(void) · 2 unmodified lines
58	74	printf("};\n");
59	75	}
60	76
	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	+
61	89	int main(int argc, char *argv[])
62	90	{
63		− generate_crc64_table();
64		− print_crc64_table();
	91	+ generate_crc64_table(crc64_table, CRC64_ECMA182_POLY);
	92	+ generate_reflected_crc64_table(crc64_rocksoft_table, CRC64_ROCKSOFT_POLY);
	93	+ print_crc64_tables();
65	94	return 0;
66	95	}

lib: add rocksoft model crc64

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