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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright 2002-2007 H. Peter Anvin - All Rights Reserved
4 *
5 * Make RAID-6 tables. This is a host user space program to be run at compile
6 * time.
7 */
8
9#include <stdio.h>
10#include <string.h>
11#include <inttypes.h>
12#include <stdlib.h>
13#include <time.h>
14
15static uint8_t gfmul(uint8_t a, uint8_t b)
16{
17 uint8_t v = 0;
18
19 while (b) {
20 if (b & 1)
21 v ^= a;
22 a = (a << 1) ^ (a & 0x80 ? 0x1d : 0);
23 b >>= 1;
24 }
25
26 return v;
27}
28
29static uint8_t gfpow(uint8_t a, int b)
30{
31 uint8_t v = 1;
32
33 b %= 255;
34 if (b < 0)
35 b += 255;
36
37 while (b) {
38 if (b & 1)
39 v = gfmul(v, a);
40 a = gfmul(a, a);
41 b >>= 1;
42 }
43
44 return v;
45}
46
47int main(int argc, char *argv[])
48{
49 int i, j, k;
50 uint8_t v;
51 uint8_t exptbl[256], invtbl[256];
52
53 printf("#include <linux/export.h>\n");
54 printf("#include \"algos.h\"\n");
55
56 /* Compute multiplication table */
57 printf("\nconst u8 __attribute__((aligned(256)))\n"
58 "raid6_gfmul[256][256] =\n"
59 "{\n");
60 for (i = 0; i < 256; i++) {
61 printf("\t{\n");
62 for (j = 0; j < 256; j += 8) {
63 printf("\t\t");
64 for (k = 0; k < 8; k++)
65 printf("0x%02x,%c", gfmul(i, j + k),
66 (k == 7) ? '\n' : ' ');
67 }
68 printf("\t},\n");
69 }
70 printf("};\n");
71 printf("EXPORT_SYMBOL(raid6_gfmul);\n");
72
73 /* Compute vector multiplication table */
74 printf("\nconst u8 __attribute__((aligned(256)))\n"
75 "raid6_vgfmul[256][32] =\n"
76 "{\n");
77 for (i = 0; i < 256; i++) {
78 printf("\t{\n");
79 for (j = 0; j < 16; j += 8) {
80 printf("\t\t");
81 for (k = 0; k < 8; k++)
82 printf("0x%02x,%c", gfmul(i, j + k),
83 (k == 7) ? '\n' : ' ');
84 }
85 for (j = 0; j < 16; j += 8) {
86 printf("\t\t");
87 for (k = 0; k < 8; k++)
88 printf("0x%02x,%c", gfmul(i, (j + k) << 4),
89 (k == 7) ? '\n' : ' ');
90 }
91 printf("\t},\n");
92 }
93 printf("};\n");
94 printf("EXPORT_SYMBOL(raid6_vgfmul);\n");
95
96 /* Compute power-of-2 table (exponent) */
97 v = 1;
98 printf("\nconst u8 __attribute__((aligned(256)))\n"
99 "raid6_gfexp[256] =\n" "{\n");
100 for (i = 0; i < 256; i += 8) {
101 printf("\t");
102 for (j = 0; j < 8; j++) {
103 exptbl[i + j] = v;
104 printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
105 v = gfmul(v, 2);
106 if (v == 1)
107 v = 0; /* For entry 255, not a real entry */
108 }
109 }
110 printf("};\n");
111 printf("EXPORT_SYMBOL(raid6_gfexp);\n");
112
113 /* Compute log-of-2 table */
114 printf("\nconst u8 __attribute__((aligned(256)))\n"
115 "raid6_gflog[256] =\n" "{\n");
116 for (i = 0; i < 256; i += 8) {
117 printf("\t");
118 for (j = 0; j < 8; j++) {
119 v = 255;
120 for (k = 0; k < 256; k++)
121 if (exptbl[k] == (i + j)) {
122 v = k;
123 break;
124 }
125 printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
126 }
127 }
128 printf("};\n");
129 printf("EXPORT_SYMBOL(raid6_gflog);\n");
130
131 /* Compute inverse table x^-1 == x^254 */
132 printf("\nconst u8 __attribute__((aligned(256)))\n"
133 "raid6_gfinv[256] =\n" "{\n");
134 for (i = 0; i < 256; i += 8) {
135 printf("\t");
136 for (j = 0; j < 8; j++) {
137 invtbl[i + j] = v = gfpow(i + j, 254);
138 printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
139 }
140 }
141 printf("};\n");
142 printf("EXPORT_SYMBOL(raid6_gfinv);\n");
143
144 /* Compute inv(2^x + 1) (exponent-xor-inverse) table */
145 printf("\nconst u8 __attribute__((aligned(256)))\n"
146 "raid6_gfexi[256] =\n" "{\n");
147 for (i = 0; i < 256; i += 8) {
148 printf("\t");
149 for (j = 0; j < 8; j++)
150 printf("0x%02x,%c", invtbl[exptbl[i + j] ^ 1],
151 (j == 7) ? '\n' : ' ');
152 }
153 printf("};\n");
154 printf("EXPORT_SYMBOL(raid6_gfexi);\n");
155
156 return 0;
157}