1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* -*- linux-c -*- ------------------------------------------------------- *
3 *
4 * Copyright 2002-2007 H. Peter Anvin - All Rights Reserved
5 *
6 * ----------------------------------------------------------------------- */
7
8 /*
9 * mktables.c
10 *
11 * Make RAID-6 tables. This is a host user space program to be run at
12 * compile time.
13 */
14
15 #include <stdio.h>
16 #include <string.h>
17 #include <inttypes.h>
18 #include <stdlib.h>
19 #include <time.h>
20
gfmul(uint8_t a,uint8_t b)21 static uint8_t gfmul(uint8_t a, uint8_t b)
22 {
23 uint8_t v = 0;
24
25 while (b) {
26 if (b & 1)
27 v ^= a;
28 a = (a << 1) ^ (a & 0x80 ? 0x1d : 0);
29 b >>= 1;
30 }
31
32 return v;
33 }
34
gfpow(uint8_t a,int b)35 static uint8_t gfpow(uint8_t a, int b)
36 {
37 uint8_t v = 1;
38
39 b %= 255;
40 if (b < 0)
41 b += 255;
42
43 while (b) {
44 if (b & 1)
45 v = gfmul(v, a);
46 a = gfmul(a, a);
47 b >>= 1;
48 }
49
50 return v;
51 }
52
main(int argc,char * argv[])53 int main(int argc, char *argv[])
54 {
55 int i, j, k;
56 uint8_t v;
57 uint8_t exptbl[256], invtbl[256];
58
59 printf("#include <linux/raid/pq.h>\n");
60 printf("#include <linux/export.h>\n");
61
62 /* Compute multiplication table */
63 printf("\nconst u8 __attribute__((aligned(256)))\n"
64 "raid6_gfmul[256][256] =\n"
65 "{\n");
66 for (i = 0; i < 256; i++) {
67 printf("\t{\n");
68 for (j = 0; j < 256; j += 8) {
69 printf("\t\t");
70 for (k = 0; k < 8; k++)
71 printf("0x%02x,%c", gfmul(i, j + k),
72 (k == 7) ? '\n' : ' ');
73 }
74 printf("\t},\n");
75 }
76 printf("};\n");
77 printf("#ifdef __KERNEL__\n");
78 printf("EXPORT_SYMBOL(raid6_gfmul);\n");
79 printf("#endif\n");
80
81 /* Compute vector multiplication table */
82 printf("\nconst u8 __attribute__((aligned(256)))\n"
83 "raid6_vgfmul[256][32] =\n"
84 "{\n");
85 for (i = 0; i < 256; i++) {
86 printf("\t{\n");
87 for (j = 0; j < 16; j += 8) {
88 printf("\t\t");
89 for (k = 0; k < 8; k++)
90 printf("0x%02x,%c", gfmul(i, j + k),
91 (k == 7) ? '\n' : ' ');
92 }
93 for (j = 0; j < 16; j += 8) {
94 printf("\t\t");
95 for (k = 0; k < 8; k++)
96 printf("0x%02x,%c", gfmul(i, (j + k) << 4),
97 (k == 7) ? '\n' : ' ');
98 }
99 printf("\t},\n");
100 }
101 printf("};\n");
102 printf("#ifdef __KERNEL__\n");
103 printf("EXPORT_SYMBOL(raid6_vgfmul);\n");
104 printf("#endif\n");
105
106 /* Compute power-of-2 table (exponent) */
107 v = 1;
108 printf("\nconst u8 __attribute__((aligned(256)))\n"
109 "raid6_gfexp[256] =\n" "{\n");
110 for (i = 0; i < 256; i += 8) {
111 printf("\t");
112 for (j = 0; j < 8; j++) {
113 exptbl[i + j] = v;
114 printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
115 v = gfmul(v, 2);
116 if (v == 1)
117 v = 0; /* For entry 255, not a real entry */
118 }
119 }
120 printf("};\n");
121 printf("#ifdef __KERNEL__\n");
122 printf("EXPORT_SYMBOL(raid6_gfexp);\n");
123 printf("#endif\n");
124
125 /* Compute log-of-2 table */
126 printf("\nconst u8 __attribute__((aligned(256)))\n"
127 "raid6_gflog[256] =\n" "{\n");
128 for (i = 0; i < 256; i += 8) {
129 printf("\t");
130 for (j = 0; j < 8; j++) {
131 v = 255;
132 for (k = 0; k < 256; k++)
133 if (exptbl[k] == (i + j)) {
134 v = k;
135 break;
136 }
137 printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
138 }
139 }
140 printf("};\n");
141 printf("#ifdef __KERNEL__\n");
142 printf("EXPORT_SYMBOL(raid6_gflog);\n");
143 printf("#endif\n");
144
145 /* Compute inverse table x^-1 == x^254 */
146 printf("\nconst u8 __attribute__((aligned(256)))\n"
147 "raid6_gfinv[256] =\n" "{\n");
148 for (i = 0; i < 256; i += 8) {
149 printf("\t");
150 for (j = 0; j < 8; j++) {
151 invtbl[i + j] = v = gfpow(i + j, 254);
152 printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
153 }
154 }
155 printf("};\n");
156 printf("#ifdef __KERNEL__\n");
157 printf("EXPORT_SYMBOL(raid6_gfinv);\n");
158 printf("#endif\n");
159
160 /* Compute inv(2^x + 1) (exponent-xor-inverse) table */
161 printf("\nconst u8 __attribute__((aligned(256)))\n"
162 "raid6_gfexi[256] =\n" "{\n");
163 for (i = 0; i < 256; i += 8) {
164 printf("\t");
165 for (j = 0; j < 8; j++)
166 printf("0x%02x,%c", invtbl[exptbl[i + j] ^ 1],
167 (j == 7) ? '\n' : ' ');
168 }
169 printf("};\n");
170 printf("#ifdef __KERNEL__\n");
171 printf("EXPORT_SYMBOL(raid6_gfexi);\n");
172 printf("#endif\n");
173
174 return 0;
175 }
176