mktables.c 3.9 KB

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