1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
|
/* -*- linux-c -*- ------------------------------------------------------- *
*
* Copyright 2002-2007 H. Peter Anvin - All Rights Reserved
*
* This file is part of the Linux kernel, and is made available under
* the terms of the GNU General Public License version 2 or (at your
* option) any later version; incorporated herein by reference.
*
* ----------------------------------------------------------------------- */
/*
* mktables.c
*
* Make RAID-6 tables. This is a host user space program to be run at
* compile time.
*/
/*
* Btrfs-progs port, with following minor fixes:
* 1) Use "kerncompat.h"
* 2) Get rid of __KERNEL__ related macros
*/
#include <stdio.h>
#include <inttypes.h>
static uint8_t gfmul(uint8_t a, uint8_t b)
{
uint8_t v = 0;
while (b) {
if (b & 1)
v ^= a;
a = (a << 1) ^ (a & 0x80 ? 0x1d : 0);
b >>= 1;
}
return v;
}
static uint8_t gfpow(uint8_t a, int b)
{
uint8_t v = 1;
b %= 255;
if (b < 0)
b += 255;
while (b) {
if (b & 1)
v = gfmul(v, a);
a = gfmul(a, a);
b >>= 1;
}
return v;
}
int main(int argc, char *argv[])
{
int i, j, k;
uint8_t v;
uint8_t exptbl[256], invtbl[256];
printf("#include \"kerncompat.h\"\n");
/* Compute multiplication table */
printf("\nconst u8 __attribute__((aligned(256)))\n"
"raid6_gfmul[256][256] =\n"
"{\n");
for (i = 0; i < 256; i++) {
printf("\t{\n");
for (j = 0; j < 256; j += 8) {
printf("\t\t");
for (k = 0; k < 8; k++)
printf("0x%02x,%c", gfmul(i, j + k),
(k == 7) ? '\n' : ' ');
}
printf("\t},\n");
}
printf("};\n");
/* Compute vector multiplication table */
printf("\nconst u8 __attribute__((aligned(256)))\n"
"raid6_vgfmul[256][32] =\n"
"{\n");
for (i = 0; i < 256; i++) {
printf("\t{\n");
for (j = 0; j < 16; j += 8) {
printf("\t\t");
for (k = 0; k < 8; k++)
printf("0x%02x,%c", gfmul(i, j + k),
(k == 7) ? '\n' : ' ');
}
for (j = 0; j < 16; j += 8) {
printf("\t\t");
for (k = 0; k < 8; k++)
printf("0x%02x,%c", gfmul(i, (j + k) << 4),
(k == 7) ? '\n' : ' ');
}
printf("\t},\n");
}
printf("};\n");
/* Compute power-of-2 table (exponent) */
v = 1;
printf("\nconst u8 __attribute__((aligned(256)))\n"
"raid6_gfexp[256] =\n" "{\n");
for (i = 0; i < 256; i += 8) {
printf("\t");
for (j = 0; j < 8; j++) {
exptbl[i + j] = v;
printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
v = gfmul(v, 2);
if (v == 1)
v = 0; /* For entry 255, not a real entry */
}
}
printf("};\n");
/* Compute inverse table x^-1 == x^254 */
printf("\nconst u8 __attribute__((aligned(256)))\n"
"raid6_gfinv[256] =\n" "{\n");
for (i = 0; i < 256; i += 8) {
printf("\t");
for (j = 0; j < 8; j++) {
invtbl[i + j] = v = gfpow(i + j, 254);
printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
}
}
printf("};\n");
/* Compute inv(2^x + 1) (exponent-xor-inverse) table */
printf("\nconst u8 __attribute__((aligned(256)))\n"
"raid6_gfexi[256] =\n" "{\n");
for (i = 0; i < 256; i += 8) {
printf("\t");
for (j = 0; j < 8; j++)
printf("0x%02x,%c", invtbl[exptbl[i + j] ^ 1],
(j == 7) ? '\n' : ' ');
}
printf("};\n");
return 0;
}
|
