1/* -*- linux-c -*- ------------------------------------------------------- *
2 *
3 * Copyright 2002-2007 H. Peter Anvin - All Rights Reserved
4 *
5 * This file is part of the Linux kernel, and is made available under
6 * the terms of the GNU General Public License version 2 or (at your
7 * option) any later version; incorporated herein by reference.
8 *
9 * ----------------------------------------------------------------------- */
10
11/*
12 * mktables.c
13 *
14 * Make RAID-6 tables. This is a host user space program to be run at
15 * compile time.
16 */
17
18#include <stdio.h>
19#include <string.h>
20#include <inttypes.h>
21#include <stdlib.h>
22#include <time.h>
23
24static uint8_t gfmul(uint8_t a, uint8_t b)
25{
26 uint8_t v = 0;
27
28 while (b) {
29 if (b & 1)
30 v ^= a;
31 a = (a << 1) ^ (a & 0x80 ? 0x1d : 0);
32 b >>= 1;
33 }
34
35 return v;
36}
37
38static uint8_t gfpow(uint8_t a, int b)
39{
40 uint8_t v = 1;
41
42 b %= 255;
43 if (b < 0)
44 b += 255;
45
46 while (b) {
47 if (b & 1)
48 v = gfmul(v, a);
49 a = gfmul(a, a);
50 b >>= 1;
51 }
52
53 return v;
54}
55
56int main(int argc, char *argv[])
57{
58 int i, j, k;
59 uint8_t v;
60 uint8_t exptbl[256], invtbl[256];
61
62 printf("#include <linux/raid/pq.h>\n");
63 printf("#include <linux/export.h>\n");
64
65 /* Compute multiplication table */
66 printf("\nconst u8 __attribute__((aligned(256)))\n"
67 "raid6_gfmul[256][256] =\n"
68 "{\n");
69 for (i = 0; i < 256; i++) {
70 printf("\t{\n");
71 for (j = 0; j < 256; j += 8) {
72 printf("\t\t");
73 for (k = 0; k < 8; k++)
74 printf("0x%02x,%c", gfmul(i, j + k),
75 (k == 7) ? '\n' : ' ');
76 }
77 printf("\t},\n");
78 }
79 printf("};\n");
80 printf("#ifdef __KERNEL__\n");
81 printf("EXPORT_SYMBOL(raid6_gfmul);\n");
82 printf("#endif\n");
83
84 /* Compute vector multiplication table */
85 printf("\nconst u8 __attribute__((aligned(256)))\n"
86 "raid6_vgfmul[256][32] =\n"
87 "{\n");
88 for (i = 0; i < 256; i++) {
89 printf("\t{\n");
90 for (j = 0; j < 16; j += 8) {
91 printf("\t\t");
92 for (k = 0; k < 8; k++)
93 printf("0x%02x,%c", gfmul(i, j + k),
94 (k == 7) ? '\n' : ' ');
95 }
96 for (j = 0; j < 16; j += 8) {
97 printf("\t\t");
98 for (k = 0; k < 8; k++)
99 printf("0x%02x,%c", gfmul(i, (j + k) << 4),
100 (k == 7) ? '\n' : ' ');
101 }
102 printf("\t},\n");
103 }
104 printf("};\n");
105 printf("#ifdef __KERNEL__\n");
106 printf("EXPORT_SYMBOL(raid6_vgfmul);\n");
107 printf("#endif\n");
108
109 /* Compute power-of-2 table (exponent) */
110 v = 1;
111 printf("\nconst u8 __attribute__((aligned(256)))\n"
112 "raid6_gfexp[256] =\n" "{\n");
113 for (i = 0; i < 256; i += 8) {
114 printf("\t");
115 for (j = 0; j < 8; j++) {
116 exptbl[i + j] = v;
117 printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
118 v = gfmul(v, 2);
119 if (v == 1)
120 v = 0; /* For entry 255, not a real entry */
121 }
122 }
123 printf("};\n");
124 printf("#ifdef __KERNEL__\n");
125 printf("EXPORT_SYMBOL(raid6_gfexp);\n");
126 printf("#endif\n");
127
128 /* Compute log-of-2 table */
129 printf("\nconst u8 __attribute__((aligned(256)))\n"
130 "raid6_gflog[256] =\n" "{\n");
131 for (i = 0; i < 256; i += 8) {
132 printf("\t");
133 for (j = 0; j < 8; j++) {
134 v = 255;
135 for (k = 0; k < 256; k++)
136 if (exptbl[k] == (i + j)) {
137 v = k;
138 break;
139 }
140 printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
141 }
142 }
143 printf("};\n");
144 printf("#ifdef __KERNEL__\n");
145 printf("EXPORT_SYMBOL(raid6_gflog);\n");
146 printf("#endif\n");
147
148 /* Compute inverse table x^-1 == x^254 */
149 printf("\nconst u8 __attribute__((aligned(256)))\n"
150 "raid6_gfinv[256] =\n" "{\n");
151 for (i = 0; i < 256; i += 8) {
152 printf("\t");
153 for (j = 0; j < 8; j++) {
154 invtbl[i + j] = v = gfpow(i + j, 254);
155 printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
156 }
157 }
158 printf("};\n");
159 printf("#ifdef __KERNEL__\n");
160 printf("EXPORT_SYMBOL(raid6_gfinv);\n");
161 printf("#endif\n");
162
163 /* Compute inv(2^x + 1) (exponent-xor-inverse) table */
164 printf("\nconst u8 __attribute__((aligned(256)))\n"
165 "raid6_gfexi[256] =\n" "{\n");
166 for (i = 0; i < 256; i += 8) {
167 printf("\t");
168 for (j = 0; j < 8; j++)
169 printf("0x%02x,%c", invtbl[exptbl[i + j] ^ 1],
170 (j == 7) ? '\n' : ' ');
171 }
172 printf("};\n");
173 printf("#ifdef __KERNEL__\n");
174 printf("EXPORT_SYMBOL(raid6_gfexi);\n");
175 printf("#endif\n");
176
177 return 0;
178}
179