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 24 static 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 38 static 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 56 int 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