.. | .. |
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20 | 20 | |
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21 | 21 | #include "mpi-internal.h" |
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22 | 22 | |
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| 23 | +/* Constants allocated right away at startup. */ |
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| 24 | +static MPI constants[MPI_NUMBER_OF_CONSTANTS]; |
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| 25 | + |
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| 26 | +/* Initialize the MPI subsystem. This is called early and allows to |
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| 27 | + * do some initialization without taking care of threading issues. |
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| 28 | + */ |
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| 29 | +static int __init mpi_init(void) |
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| 30 | +{ |
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| 31 | + int idx; |
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| 32 | + unsigned long value; |
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| 33 | + |
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| 34 | + for (idx = 0; idx < MPI_NUMBER_OF_CONSTANTS; idx++) { |
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| 35 | + switch (idx) { |
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| 36 | + case MPI_C_ZERO: |
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| 37 | + value = 0; |
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| 38 | + break; |
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| 39 | + case MPI_C_ONE: |
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| 40 | + value = 1; |
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| 41 | + break; |
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| 42 | + case MPI_C_TWO: |
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| 43 | + value = 2; |
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| 44 | + break; |
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| 45 | + case MPI_C_THREE: |
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| 46 | + value = 3; |
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| 47 | + break; |
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| 48 | + case MPI_C_FOUR: |
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| 49 | + value = 4; |
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| 50 | + break; |
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| 51 | + case MPI_C_EIGHT: |
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| 52 | + value = 8; |
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| 53 | + break; |
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| 54 | + default: |
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| 55 | + pr_err("MPI: invalid mpi_const selector %d\n", idx); |
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| 56 | + return -EFAULT; |
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| 57 | + } |
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| 58 | + constants[idx] = mpi_alloc_set_ui(value); |
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| 59 | + constants[idx]->flags = (16|32); |
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| 60 | + } |
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| 61 | + |
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| 62 | + return 0; |
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| 63 | +} |
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| 64 | +postcore_initcall(mpi_init); |
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| 65 | + |
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| 66 | +/* Return a constant MPI descripbed by NO which is one of the |
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| 67 | + * MPI_C_xxx macros. There is no need to copy this returned value; it |
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| 68 | + * may be used directly. |
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| 69 | + */ |
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| 70 | +MPI mpi_const(enum gcry_mpi_constants no) |
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| 71 | +{ |
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| 72 | + if ((int)no < 0 || no > MPI_NUMBER_OF_CONSTANTS) |
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| 73 | + pr_err("MPI: invalid mpi_const selector %d\n", no); |
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| 74 | + if (!constants[no]) |
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| 75 | + pr_err("MPI: MPI subsystem not initialized\n"); |
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| 76 | + return constants[no]; |
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| 77 | +} |
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| 78 | +EXPORT_SYMBOL_GPL(mpi_const); |
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| 79 | + |
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23 | 80 | /**************** |
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24 | 81 | * Note: It was a bad idea to use the number of limbs to allocate |
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25 | 82 | * because on a alpha the limbs are large but we normally need |
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.. | .. |
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69 | 126 | if (!a) |
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70 | 127 | return; |
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71 | 128 | |
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72 | | - kzfree(a); |
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| 129 | + kfree_sensitive(a); |
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73 | 130 | } |
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74 | 131 | |
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75 | 132 | void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs) |
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.. | .. |
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95 | 152 | if (!p) |
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96 | 153 | return -ENOMEM; |
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97 | 154 | memcpy(p, a->d, a->alloced * sizeof(mpi_limb_t)); |
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98 | | - kzfree(a->d); |
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| 155 | + kfree_sensitive(a->d); |
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99 | 156 | a->d = p; |
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100 | 157 | } else { |
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101 | 158 | a->d = kcalloc(nlimbs, sizeof(mpi_limb_t), GFP_KERNEL); |
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.. | .. |
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106 | 163 | return 0; |
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107 | 164 | } |
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108 | 165 | |
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| 166 | +void mpi_clear(MPI a) |
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| 167 | +{ |
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| 168 | + if (!a) |
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| 169 | + return; |
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| 170 | + a->nlimbs = 0; |
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| 171 | + a->flags = 0; |
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| 172 | +} |
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| 173 | +EXPORT_SYMBOL_GPL(mpi_clear); |
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| 174 | + |
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109 | 175 | void mpi_free(MPI a) |
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110 | 176 | { |
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111 | 177 | if (!a) |
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112 | 178 | return; |
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113 | 179 | |
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114 | 180 | if (a->flags & 4) |
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115 | | - kzfree(a->d); |
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| 181 | + kfree_sensitive(a->d); |
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116 | 182 | else |
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117 | 183 | mpi_free_limb_space(a->d); |
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118 | 184 | |
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.. | .. |
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122 | 188 | } |
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123 | 189 | EXPORT_SYMBOL_GPL(mpi_free); |
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124 | 190 | |
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| 191 | +/**************** |
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| 192 | + * Note: This copy function should not interpret the MPI |
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| 193 | + * but copy it transparently. |
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| 194 | + */ |
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| 195 | +MPI mpi_copy(MPI a) |
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| 196 | +{ |
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| 197 | + int i; |
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| 198 | + MPI b; |
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| 199 | + |
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| 200 | + if (a) { |
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| 201 | + b = mpi_alloc(a->nlimbs); |
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| 202 | + b->nlimbs = a->nlimbs; |
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| 203 | + b->sign = a->sign; |
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| 204 | + b->flags = a->flags; |
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| 205 | + b->flags &= ~(16|32); /* Reset the immutable and constant flags. */ |
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| 206 | + for (i = 0; i < b->nlimbs; i++) |
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| 207 | + b->d[i] = a->d[i]; |
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| 208 | + } else |
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| 209 | + b = NULL; |
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| 210 | + return b; |
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| 211 | +} |
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| 212 | + |
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| 213 | +/**************** |
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| 214 | + * This function allocates an MPI which is optimized to hold |
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| 215 | + * a value as large as the one given in the argument and allocates it |
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| 216 | + * with the same flags as A. |
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| 217 | + */ |
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| 218 | +MPI mpi_alloc_like(MPI a) |
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| 219 | +{ |
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| 220 | + MPI b; |
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| 221 | + |
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| 222 | + if (a) { |
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| 223 | + b = mpi_alloc(a->nlimbs); |
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| 224 | + b->nlimbs = 0; |
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| 225 | + b->sign = 0; |
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| 226 | + b->flags = a->flags; |
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| 227 | + } else |
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| 228 | + b = NULL; |
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| 229 | + |
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| 230 | + return b; |
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| 231 | +} |
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| 232 | + |
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| 233 | + |
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| 234 | +/* Set U into W and release U. If W is NULL only U will be released. */ |
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| 235 | +void mpi_snatch(MPI w, MPI u) |
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| 236 | +{ |
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| 237 | + if (w) { |
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| 238 | + mpi_assign_limb_space(w, u->d, u->alloced); |
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| 239 | + w->nlimbs = u->nlimbs; |
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| 240 | + w->sign = u->sign; |
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| 241 | + w->flags = u->flags; |
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| 242 | + u->alloced = 0; |
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| 243 | + u->nlimbs = 0; |
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| 244 | + u->d = NULL; |
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| 245 | + } |
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| 246 | + mpi_free(u); |
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| 247 | +} |
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| 248 | + |
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| 249 | + |
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| 250 | +MPI mpi_set(MPI w, MPI u) |
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| 251 | +{ |
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| 252 | + mpi_ptr_t wp, up; |
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| 253 | + mpi_size_t usize = u->nlimbs; |
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| 254 | + int usign = u->sign; |
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| 255 | + |
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| 256 | + if (!w) |
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| 257 | + w = mpi_alloc(mpi_get_nlimbs(u)); |
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| 258 | + RESIZE_IF_NEEDED(w, usize); |
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| 259 | + wp = w->d; |
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| 260 | + up = u->d; |
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| 261 | + MPN_COPY(wp, up, usize); |
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| 262 | + w->nlimbs = usize; |
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| 263 | + w->flags = u->flags; |
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| 264 | + w->flags &= ~(16|32); /* Reset the immutable and constant flags. */ |
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| 265 | + w->sign = usign; |
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| 266 | + return w; |
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| 267 | +} |
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| 268 | +EXPORT_SYMBOL_GPL(mpi_set); |
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| 269 | + |
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| 270 | +MPI mpi_set_ui(MPI w, unsigned long u) |
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| 271 | +{ |
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| 272 | + if (!w) |
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| 273 | + w = mpi_alloc(1); |
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| 274 | + /* FIXME: If U is 0 we have no need to resize and thus possible |
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| 275 | + * allocating the the limbs. |
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| 276 | + */ |
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| 277 | + RESIZE_IF_NEEDED(w, 1); |
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| 278 | + w->d[0] = u; |
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| 279 | + w->nlimbs = u ? 1 : 0; |
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| 280 | + w->sign = 0; |
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| 281 | + w->flags = 0; |
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| 282 | + return w; |
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| 283 | +} |
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| 284 | +EXPORT_SYMBOL_GPL(mpi_set_ui); |
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| 285 | + |
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| 286 | +MPI mpi_alloc_set_ui(unsigned long u) |
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| 287 | +{ |
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| 288 | + MPI w = mpi_alloc(1); |
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| 289 | + w->d[0] = u; |
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| 290 | + w->nlimbs = u ? 1 : 0; |
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| 291 | + w->sign = 0; |
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| 292 | + return w; |
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| 293 | +} |
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| 294 | + |
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| 295 | +/**************** |
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| 296 | + * Swap the value of A and B, when SWAP is 1. |
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| 297 | + * Leave the value when SWAP is 0. |
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| 298 | + * This implementation should be constant-time regardless of SWAP. |
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| 299 | + */ |
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| 300 | +void mpi_swap_cond(MPI a, MPI b, unsigned long swap) |
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| 301 | +{ |
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| 302 | + mpi_size_t i; |
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| 303 | + mpi_size_t nlimbs; |
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| 304 | + mpi_limb_t mask = ((mpi_limb_t)0) - swap; |
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| 305 | + mpi_limb_t x; |
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| 306 | + |
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| 307 | + if (a->alloced > b->alloced) |
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| 308 | + nlimbs = b->alloced; |
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| 309 | + else |
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| 310 | + nlimbs = a->alloced; |
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| 311 | + if (a->nlimbs > nlimbs || b->nlimbs > nlimbs) |
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| 312 | + return; |
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| 313 | + |
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| 314 | + for (i = 0; i < nlimbs; i++) { |
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| 315 | + x = mask & (a->d[i] ^ b->d[i]); |
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| 316 | + a->d[i] = a->d[i] ^ x; |
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| 317 | + b->d[i] = b->d[i] ^ x; |
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| 318 | + } |
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| 319 | + |
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| 320 | + x = mask & (a->nlimbs ^ b->nlimbs); |
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| 321 | + a->nlimbs = a->nlimbs ^ x; |
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| 322 | + b->nlimbs = b->nlimbs ^ x; |
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| 323 | + |
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| 324 | + x = mask & (a->sign ^ b->sign); |
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| 325 | + a->sign = a->sign ^ x; |
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| 326 | + b->sign = b->sign ^ x; |
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| 327 | +} |
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| 328 | + |
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125 | 329 | MODULE_DESCRIPTION("Multiprecision maths library"); |
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126 | 330 | MODULE_LICENSE("GPL"); |
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