1 // SPDX-License-Identifier: BSD-2-Clause
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31 #include <linux/limits.h>
32 #include <linux/string.h> /* for memset */
33 #include <libcfs/libcfs.h>
34 #include "erasure_code.h"
36 /* Global GF(256) tables */
37 static const unsigned char gff_base[] = {
38 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1d, 0x3a,
39 0x74, 0xe8, 0xcd, 0x87, 0x13, 0x26, 0x4c, 0x98, 0x2d, 0x5a,
40 0xb4, 0x75, 0xea, 0xc9, 0x8f, 0x03, 0x06, 0x0c, 0x18, 0x30,
41 0x60, 0xc0, 0x9d, 0x27, 0x4e, 0x9c, 0x25, 0x4a, 0x94, 0x35,
42 0x6a, 0xd4, 0xb5, 0x77, 0xee, 0xc1, 0x9f, 0x23, 0x46, 0x8c,
43 0x05, 0x0a, 0x14, 0x28, 0x50, 0xa0, 0x5d, 0xba, 0x69, 0xd2,
44 0xb9, 0x6f, 0xde, 0xa1, 0x5f, 0xbe, 0x61, 0xc2, 0x99, 0x2f,
45 0x5e, 0xbc, 0x65, 0xca, 0x89, 0x0f, 0x1e, 0x3c, 0x78, 0xf0,
46 0xfd, 0xe7, 0xd3, 0xbb, 0x6b, 0xd6, 0xb1, 0x7f, 0xfe, 0xe1,
47 0xdf, 0xa3, 0x5b, 0xb6, 0x71, 0xe2, 0xd9, 0xaf, 0x43, 0x86,
48 0x11, 0x22, 0x44, 0x88, 0x0d, 0x1a, 0x34, 0x68, 0xd0, 0xbd,
49 0x67, 0xce, 0x81, 0x1f, 0x3e, 0x7c, 0xf8, 0xed, 0xc7, 0x93,
50 0x3b, 0x76, 0xec, 0xc5, 0x97, 0x33, 0x66, 0xcc, 0x85, 0x17,
51 0x2e, 0x5c, 0xb8, 0x6d, 0xda, 0xa9, 0x4f, 0x9e, 0x21, 0x42,
52 0x84, 0x15, 0x2a, 0x54, 0xa8, 0x4d, 0x9a, 0x29, 0x52, 0xa4,
53 0x55, 0xaa, 0x49, 0x92, 0x39, 0x72, 0xe4, 0xd5, 0xb7, 0x73,
54 0xe6, 0xd1, 0xbf, 0x63, 0xc6, 0x91, 0x3f, 0x7e, 0xfc, 0xe5,
55 0xd7, 0xb3, 0x7b, 0xf6, 0xf1, 0xff, 0xe3, 0xdb, 0xab, 0x4b,
56 0x96, 0x31, 0x62, 0xc4, 0x95, 0x37, 0x6e, 0xdc, 0xa5, 0x57,
57 0xae, 0x41, 0x82, 0x19, 0x32, 0x64, 0xc8, 0x8d, 0x07, 0x0e,
58 0x1c, 0x38, 0x70, 0xe0, 0xdd, 0xa7, 0x53, 0xa6, 0x51, 0xa2,
59 0x59, 0xb2, 0x79, 0xf2, 0xf9, 0xef, 0xc3, 0x9b, 0x2b, 0x56,
60 0xac, 0x45, 0x8a, 0x09, 0x12, 0x24, 0x48, 0x90, 0x3d, 0x7a,
61 0xf4, 0xf5, 0xf7, 0xf3, 0xfb, 0xeb, 0xcb, 0x8b, 0x0b, 0x16,
62 0x2c, 0x58, 0xb0, 0x7d, 0xfa, 0xe9, 0xcf, 0x83, 0x1b, 0x36,
63 0x6c, 0xd8, 0xad, 0x47, 0x8e, 0x01
66 static const unsigned char gflog_base[] = {
67 0x00, 0xff, 0x01, 0x19, 0x02, 0x32, 0x1a, 0xc6, 0x03, 0xdf,
68 0x33, 0xee, 0x1b, 0x68, 0xc7, 0x4b, 0x04, 0x64, 0xe0, 0x0e,
69 0x34, 0x8d, 0xef, 0x81, 0x1c, 0xc1, 0x69, 0xf8, 0xc8, 0x08,
70 0x4c, 0x71, 0x05, 0x8a, 0x65, 0x2f, 0xe1, 0x24, 0x0f, 0x21,
71 0x35, 0x93, 0x8e, 0xda, 0xf0, 0x12, 0x82, 0x45, 0x1d, 0xb5,
72 0xc2, 0x7d, 0x6a, 0x27, 0xf9, 0xb9, 0xc9, 0x9a, 0x09, 0x78,
73 0x4d, 0xe4, 0x72, 0xa6, 0x06, 0xbf, 0x8b, 0x62, 0x66, 0xdd,
74 0x30, 0xfd, 0xe2, 0x98, 0x25, 0xb3, 0x10, 0x91, 0x22, 0x88,
75 0x36, 0xd0, 0x94, 0xce, 0x8f, 0x96, 0xdb, 0xbd, 0xf1, 0xd2,
76 0x13, 0x5c, 0x83, 0x38, 0x46, 0x40, 0x1e, 0x42, 0xb6, 0xa3,
77 0xc3, 0x48, 0x7e, 0x6e, 0x6b, 0x3a, 0x28, 0x54, 0xfa, 0x85,
78 0xba, 0x3d, 0xca, 0x5e, 0x9b, 0x9f, 0x0a, 0x15, 0x79, 0x2b,
79 0x4e, 0xd4, 0xe5, 0xac, 0x73, 0xf3, 0xa7, 0x57, 0x07, 0x70,
80 0xc0, 0xf7, 0x8c, 0x80, 0x63, 0x0d, 0x67, 0x4a, 0xde, 0xed,
81 0x31, 0xc5, 0xfe, 0x18, 0xe3, 0xa5, 0x99, 0x77, 0x26, 0xb8,
82 0xb4, 0x7c, 0x11, 0x44, 0x92, 0xd9, 0x23, 0x20, 0x89, 0x2e,
83 0x37, 0x3f, 0xd1, 0x5b, 0x95, 0xbc, 0xcf, 0xcd, 0x90, 0x87,
84 0x97, 0xb2, 0xdc, 0xfc, 0xbe, 0x61, 0xf2, 0x56, 0xd3, 0xab,
85 0x14, 0x2a, 0x5d, 0x9e, 0x84, 0x3c, 0x39, 0x53, 0x47, 0x6d,
86 0x41, 0xa2, 0x1f, 0x2d, 0x43, 0xd8, 0xb7, 0x7b, 0xa4, 0x76,
87 0xc4, 0x17, 0x49, 0xec, 0x7f, 0x0c, 0x6f, 0xf6, 0x6c, 0xa1,
88 0x3b, 0x52, 0x29, 0x9d, 0x55, 0xaa, 0xfb, 0x60, 0x86, 0xb1,
89 0xbb, 0xcc, 0x3e, 0x5a, 0xcb, 0x59, 0x5f, 0xb0, 0x9c, 0xa9,
90 0xa0, 0x51, 0x0b, 0xf5, 0x16, 0xeb, 0x7a, 0x75, 0x2c, 0xd7,
91 0x4f, 0xae, 0xd5, 0xe9, 0xe6, 0xe7, 0xad, 0xe8, 0x74, 0xd6,
92 0xf4, 0xea, 0xa8, 0x50, 0x58, 0xaf
95 void ec_init_tables(int k, int rows, unsigned char *a, unsigned char *g_tbls)
99 for (i = 0; i < rows; i++) {
100 for (j = 0; j < k; j++) {
101 gf_vect_mul_init(*a++, g_tbls);
106 EXPORT_SYMBOL(ec_init_tables);
108 static unsigned char gf_mul(unsigned char a, unsigned char b)
112 if ((a == 0) || (b == 0))
115 i = gflog_base[a] + gflog_base[b];
116 return gff_base[i > 254 ? i - 255 : i];
119 static unsigned char gf_inv(unsigned char a)
124 return gff_base[255 - gflog_base[a]];
127 void gf_gen_cauchy1_matrix(unsigned char *a, int m, int k)
132 /* Identity matrix in high position */
134 for (i = 0; i < k; i++)
137 /* For the rest choose 1/(i + j) | i != j */
139 for (i = k; i < m; i++)
140 for (j = 0; j < k; j++)
141 *p++ = gf_inv(i ^ j);
144 EXPORT_SYMBOL(gf_gen_cauchy1_matrix);
146 int gf_invert_matrix(unsigned char *in_mat, unsigned char *out_mat, const int n)
151 /* Set out_mat[] to the identity matrix */
152 for (i = 0; i < n * n; i++) /* memset(out_mat, 0, n*n) */
155 for (i = 0; i < n; i++)
156 out_mat[i * n + i] = 1;
159 for (i = 0; i < n; i++) {
160 /* Check for 0 in pivot element */
161 if (in_mat[i * n + i] == 0) {
162 /* Find a row with non-zero in current column and swap */
163 for (j = i + 1; j < n; j++)
164 if (in_mat[j * n + i])
167 if (j == n) /* Couldn't find means it's singular */
170 for (k = 0; k < n; k++) { /* Swap rows i,j */
171 temp = in_mat[i * n + k];
172 in_mat[i * n + k] = in_mat[j * n + k];
173 in_mat[j * n + k] = temp;
175 temp = out_mat[i * n + k];
176 out_mat[i * n + k] = out_mat[j * n + k];
177 out_mat[j * n + k] = temp;
181 temp = gf_inv(in_mat[i * n + i]); /* 1/pivot */
182 for (j = 0; j < n; j++) { /* Scale row i by 1/pivot */
183 in_mat[i * n + j] = gf_mul(in_mat[i * n + j], temp);
184 out_mat[i * n + j] = gf_mul(out_mat[i * n + j], temp);
187 for (j = 0; j < n; j++) {
191 temp = in_mat[j * n + i];
192 for (k = 0; k < n; k++) {
193 out_mat[j * n + k] ^= gf_mul(temp, out_mat[i * n + k]);
194 in_mat[j * n + k] ^= gf_mul(temp, in_mat[i * n + k]);
200 EXPORT_SYMBOL(gf_invert_matrix);
202 /* Calculates const table gftbl in GF(2^8) from single input A
203 * gftbl(A) = {A{00}, A{01}, A{02}, ... , A{0f} }, {A{00}, A{10}, A{20}, ... ,
206 void gf_vect_mul_init(unsigned char c, unsigned char *tbl)
208 unsigned char c2 = (c << 1) ^ ((c & 0x80) ? 0x1d : 0); /* Mult by
211 unsigned char c4 = (c2 << 1) ^ ((c2 & 0x80) ? 0x1d : 0); /* Mult by
214 unsigned char c8 = (c4 << 1) ^ ((c4 & 0x80) ? 0x1d : 0); /* Mult by
217 #if BITS_PER_LONG == 64
218 unsigned long long v1, v2, v4, v8, *t;
219 unsigned long long v10, v20, v40, v80;
220 unsigned char c17, c18, c20, c24;
222 t = (unsigned long long *)tbl;
224 v1 = c * 0x0100010001000100ull;
225 v2 = c2 * 0x0101000001010000ull;
226 v4 = c4 * 0x0101010100000000ull;
227 v8 = c8 * 0x0101010101010101ull;
233 c17 = (c8 << 1) ^ ((c8 & 0x80) ? 0x1d : 0); //Mult by GF{2}
234 c18 = (c17 << 1) ^ ((c17 & 0x80) ? 0x1d : 0); //Mult by GF{2}
235 c20 = (c18 << 1) ^ ((c18 & 0x80) ? 0x1d : 0); //Mult by GF{2}
236 c24 = (c20 << 1) ^ ((c20 & 0x80) ? 0x1d : 0); //Mult by GF{2}
238 v10 = c17 * 0x0100010001000100ull;
239 v20 = c18 * 0x0101000001010000ull;
240 v40 = c20 * 0x0101010100000000ull;
241 v80 = c24 * 0x0101010101010101ull;
243 v40 = v10 ^ v20 ^ v40;
247 #else /* 32-bit or other */
248 unsigned char c3, c5, c6, c7, c9, c10, c11, c12, c13, c14, c15;
249 unsigned char c17, c18, c19, c20, c21, c22, c23, c24, c25, c26;
250 unsigned char c27, c28, c29, c30, c31;
282 c17 = (c8 << 1) ^ ((c8 & 0x80) ? 0x1d : 0); /* Mult by GF{2} */
283 c18 = (c17 << 1) ^ ((c17 & 0x80) ? 0x1d : 0); /* Mult by GF{2} */
285 c20 = (c18 << 1) ^ ((c18 & 0x80) ? 0x1d : 0); /* Mult by GF{2} */
289 c24 = (c20 << 1) ^ ((c20 & 0x80) ? 0x1d : 0); /* Mult by GF{2} */
315 #endif /* BITS_PER_LONG == 64 */
318 void ec_encode_data(int len, int srcs, int dests, unsigned char *v,
319 unsigned char **src, unsigned char **dest)
324 for (l = 0; l < dests; l++) {
325 for (i = 0; i < len; i++) {
327 for (j = 0; j < srcs; j++)
328 s ^= gf_mul(src[j][i], v[j * 32 + l * srcs * 32 + 1]);
334 EXPORT_SYMBOL(ec_encode_data);
336 static int __init ec_init(void)
341 static void __exit ec_exit(void)
345 MODULE_AUTHOR("Intel Corporation");
346 MODULE_DESCRIPTION("M to N erasure code handling");
347 MODULE_VERSION("1.0.0");
348 MODULE_LICENSE("Dual BSD/GPL");
350 module_init(ec_init);
351 module_exit(ec_exit);