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 inverse table x^-1 == x^254 */
129	printf("\nconst u8 __attribute__((aligned(256)))\n"
130	       "raid6_gfinv[256] =\n" "{\n");
131	for (i = 0; i < 256; i += 8) {
132		printf("\t");
133		for (j = 0; j < 8; j++) {
134			invtbl[i + j] = v = gfpow(i + j, 254);
135			printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
136		}
137	}
138	printf("};\n");
139	printf("#ifdef __KERNEL__\n");
140	printf("EXPORT_SYMBOL(raid6_gfinv);\n");
141	printf("#endif\n");
142
143	/* Compute inv(2^x + 1) (exponent-xor-inverse) table */
144	printf("\nconst u8 __attribute__((aligned(256)))\n"
145	       "raid6_gfexi[256] =\n" "{\n");
146	for (i = 0; i < 256; i += 8) {
147		printf("\t");
148		for (j = 0; j < 8; j++)
149			printf("0x%02x,%c", invtbl[exptbl[i + j] ^ 1],
150			       (j == 7) ? '\n' : ' ');
151	}
152	printf("};\n");
153	printf("#ifdef __KERNEL__\n");
154	printf("EXPORT_SYMBOL(raid6_gfexi);\n");
155	printf("#endif\n");
156
157	return 0;
158}
159