drivers/crypto/padlock-aes.c

   1 /*
   2  * Cryptographic API.
   3  *
   4  * Support for VIA PadLock hardware crypto engine.
   5  *
   6  * Copyright (c) 2004  Michal Ludvig <michal@logix.cz>
   7  *
   8  * Key expansion routine taken from crypto/aes.c
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * ---------------------------------------------------------------------------
  16  * Copyright (c) 2002, Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK.
  17  * All rights reserved.
  18  *
  19  * LICENSE TERMS
  20  *
  21  * The free distribution and use of this software in both source and binary
  22  * form is allowed (with or without changes) provided that:
  23  *
  24  *   1. distributions of this source code include the above copyright
  25  *      notice, this list of conditions and the following disclaimer;
  26  *
  27  *   2. distributions in binary form include the above copyright
  28  *      notice, this list of conditions and the following disclaimer
  29  *      in the documentation and/or other associated materials;
  30  *
  31  *   3. the copyright holder's name is not used to endorse products
  32  *      built using this software without specific written permission.
  33  *
  34  * ALTERNATIVELY, provided that this notice is retained in full, this product
  35  * may be distributed under the terms of the GNU General Public License (GPL),
  36  * in which case the provisions of the GPL apply INSTEAD OF those given above.
  37  *
  38  * DISCLAIMER
  39  *
  40  * This software is provided 'as is' with no explicit or implied warranties
  41  * in respect of its properties, including, but not limited to, correctness
  42  * and/or fitness for purpose.
  43  * ---------------------------------------------------------------------------
  44  */
  45
  46 #include <crypto/algapi.h>
  47 #include <linux/module.h>
  48 #include <linux/init.h>
  49 #include <linux/types.h>
  50 #include <linux/errno.h>
  51 #include <linux/interrupt.h>
  52 #include <linux/kernel.h>
  53 #include <asm/byteorder.h>
  54 #include "padlock.h"
  55
  56 #define AES_MIN_KEY_SIZE        16      /* in uint8_t units */
  57 #define AES_MAX_KEY_SIZE        32      /* ditto */
  58 #define AES_BLOCK_SIZE          16      /* ditto */
  59 #define AES_EXTENDED_KEY_SIZE   64      /* in uint32_t units */
  60 #define AES_EXTENDED_KEY_SIZE_B (AES_EXTENDED_KEY_SIZE * sizeof(uint32_t))
  61
  62 /* Control word. */
  63 struct cword {
  64         unsigned int __attribute__ ((__packed__))
  65                 rounds:4,
  66                 algo:3,
  67                 keygen:1,
  68                 interm:1,
  69                 encdec:1,
  70                 ksize:2;
  71 } __attribute__ ((__aligned__(PADLOCK_ALIGNMENT)));
  72
  73 /* Whenever making any changes to the following
  74  * structure *make sure* you keep E, d_data
  75  * and cword aligned on 16 Bytes boundaries!!! */
  76 struct aes_ctx {
  77         struct {
  78                 struct cword encrypt;
  79                 struct cword decrypt;
  80         } cword;
  81         u32 *D;
  82         int key_length;
  83         u32 E[AES_EXTENDED_KEY_SIZE]
  84                 __attribute__ ((__aligned__(PADLOCK_ALIGNMENT)));
  85         u32 d_data[AES_EXTENDED_KEY_SIZE]
  86                 __attribute__ ((__aligned__(PADLOCK_ALIGNMENT)));
  87 };
  88
  89 /* ====== Key management routines ====== */
  90
  91 static inline uint32_t
  92 generic_rotr32 (const uint32_t x, const unsigned bits)
  93 {
  94         const unsigned n = bits % 32;
  95         return (x >> n) | (x << (32 - n));
  96 }
  97
  98 static inline uint32_t
  99 generic_rotl32 (const uint32_t x, const unsigned bits)
 100 {
 101         const unsigned n = bits % 32;
 102         return (x << n) | (x >> (32 - n));
 103 }
 104
 105 #define rotl generic_rotl32
 106 #define rotr generic_rotr32
 107
 108 /*
 109  * #define byte(x, nr) ((unsigned char)((x) >> (nr*8)))
 110  */
 111 static inline uint8_t
 112 byte(const uint32_t x, const unsigned n)
 113 {
 114         return x >> (n << 3);
 115 }
 116
 117 #define E_KEY ctx->E
 118 #define D_KEY ctx->D
 119
 120 static uint8_t pow_tab[256];
 121 static uint8_t log_tab[256];
 122 static uint8_t sbx_tab[256];
 123 static uint8_t isb_tab[256];
 124 static uint32_t rco_tab[10];
 125 static uint32_t ft_tab[4][256];
 126 static uint32_t it_tab[4][256];
 127
 128 static uint32_t fl_tab[4][256];
 129 static uint32_t il_tab[4][256];
 130
 131 static inline uint8_t
 132 f_mult (uint8_t a, uint8_t b)
 133 {
 134         uint8_t aa = log_tab[a], cc = aa + log_tab[b];
 135
 136         return pow_tab[cc + (cc < aa ? 1 : 0)];
 137 }
 138
 139 #define ff_mult(a,b)    (a && b ? f_mult(a, b) : 0)
 140
 141 #define f_rn(bo, bi, n, k)                                      \
 142     bo[n] =  ft_tab[0][byte(bi[n],0)] ^                         \
 143              ft_tab[1][byte(bi[(n + 1) & 3],1)] ^               \
 144              ft_tab[2][byte(bi[(n + 2) & 3],2)] ^               \
 145              ft_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n)
 146
 147 #define i_rn(bo, bi, n, k)                                      \
 148     bo[n] =  it_tab[0][byte(bi[n],0)] ^                         \
 149              it_tab[1][byte(bi[(n + 3) & 3],1)] ^               \
 150              it_tab[2][byte(bi[(n + 2) & 3],2)] ^               \
 151              it_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n)
 152
 153 #define ls_box(x)                               \
 154     ( fl_tab[0][byte(x, 0)] ^                   \
 155       fl_tab[1][byte(x, 1)] ^                   \
 156       fl_tab[2][byte(x, 2)] ^                   \
 157       fl_tab[3][byte(x, 3)] )
 158
 159 #define f_rl(bo, bi, n, k)                                      \
 160     bo[n] =  fl_tab[0][byte(bi[n],0)] ^                         \
 161              fl_tab[1][byte(bi[(n + 1) & 3],1)] ^               \
 162              fl_tab[2][byte(bi[(n + 2) & 3],2)] ^               \
 163              fl_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n)
 164
 165 #define i_rl(bo, bi, n, k)                                      \
 166     bo[n] =  il_tab[0][byte(bi[n],0)] ^                         \
 167              il_tab[1][byte(bi[(n + 3) & 3],1)] ^               \
 168              il_tab[2][byte(bi[(n + 2) & 3],2)] ^               \
 169              il_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n)
 170
 171 static void
 172 gen_tabs (void)
 173 {
 174         uint32_t i, t;
 175         uint8_t p, q;
 176
 177         /* log and power tables for GF(2**8) finite field with
 178            0x011b as modular polynomial - the simplest prmitive
 179            root is 0x03, used here to generate the tables */
 180
 181         for (i = 0, p = 1; i < 256; ++i) {
 182                 pow_tab[i] = (uint8_t) p;
 183                 log_tab[p] = (uint8_t) i;
 184
 185                 p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0);
 186         }
 187
 188         log_tab[1] = 0;
 189
 190         for (i = 0, p = 1; i < 10; ++i) {
 191                 rco_tab[i] = p;
 192
 193                 p = (p << 1) ^ (p & 0x80 ? 0x01b : 0);
 194         }
 195
 196         for (i = 0; i < 256; ++i) {
 197                 p = (i ? pow_tab[255 - log_tab[i]] : 0);
 198                 q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2));
 199                 p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2));
 200                 sbx_tab[i] = p;
 201                 isb_tab[p] = (uint8_t) i;
 202         }
 203
 204         for (i = 0; i < 256; ++i) {
 205                 p = sbx_tab[i];
 206
 207                 t = p;
 208                 fl_tab[0][i] = t;
 209                 fl_tab[1][i] = rotl (t, 8);
 210                 fl_tab[2][i] = rotl (t, 16);
 211                 fl_tab[3][i] = rotl (t, 24);
 212
 213                 t = ((uint32_t) ff_mult (2, p)) |
 214                     ((uint32_t) p << 8) |
 215                     ((uint32_t) p << 16) | ((uint32_t) ff_mult (3, p) << 24);
 216
 217                 ft_tab[0][i] = t;
 218                 ft_tab[1][i] = rotl (t, 8);
 219                 ft_tab[2][i] = rotl (t, 16);
 220                 ft_tab[3][i] = rotl (t, 24);
 221
 222                 p = isb_tab[i];
 223
 224                 t = p;
 225                 il_tab[0][i] = t;
 226                 il_tab[1][i] = rotl (t, 8);
 227                 il_tab[2][i] = rotl (t, 16);
 228                 il_tab[3][i] = rotl (t, 24);
 229
 230                 t = ((uint32_t) ff_mult (14, p)) |
 231                     ((uint32_t) ff_mult (9, p) << 8) |
 232                     ((uint32_t) ff_mult (13, p) << 16) |
 233                     ((uint32_t) ff_mult (11, p) << 24);
 234
 235                 it_tab[0][i] = t;
 236                 it_tab[1][i] = rotl (t, 8);
 237                 it_tab[2][i] = rotl (t, 16);
 238                 it_tab[3][i] = rotl (t, 24);
 239         }
 240 }
 241
 242 #define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b)
 243
 244 #define imix_col(y,x)       \
 245     u   = star_x(x);        \
 246     v   = star_x(u);        \
 247     w   = star_x(v);        \
 248     t   = w ^ (x);          \
 249    (y)  = u ^ v ^ w;        \
 250    (y) ^= rotr(u ^ t,  8) ^ \
 251           rotr(v ^ t, 16) ^ \
 252           rotr(t,24)
 253
 254 /* initialise the key schedule from the user supplied key */
 255
 256 #define loop4(i)                                    \
 257 {   t = rotr(t,  8); t = ls_box(t) ^ rco_tab[i];    \
 258     t ^= E_KEY[4 * i];     E_KEY[4 * i + 4] = t;    \
 259     t ^= E_KEY[4 * i + 1]; E_KEY[4 * i + 5] = t;    \
 260     t ^= E_KEY[4 * i + 2]; E_KEY[4 * i + 6] = t;    \
 261     t ^= E_KEY[4 * i + 3]; E_KEY[4 * i + 7] = t;    \
 262 }
 263
 264 #define loop6(i)                                    \
 265 {   t = rotr(t,  8); t = ls_box(t) ^ rco_tab[i];    \
 266     t ^= E_KEY[6 * i];     E_KEY[6 * i + 6] = t;    \
 267     t ^= E_KEY[6 * i + 1]; E_KEY[6 * i + 7] = t;    \
 268     t ^= E_KEY[6 * i + 2]; E_KEY[6 * i + 8] = t;    \
 269     t ^= E_KEY[6 * i + 3]; E_KEY[6 * i + 9] = t;    \
 270     t ^= E_KEY[6 * i + 4]; E_KEY[6 * i + 10] = t;   \
 271     t ^= E_KEY[6 * i + 5]; E_KEY[6 * i + 11] = t;   \
 272 }
 273
 274 #define loop8(i)                                    \
 275 {   t = rotr(t,  8); ; t = ls_box(t) ^ rco_tab[i];  \
 276     t ^= E_KEY[8 * i];     E_KEY[8 * i + 8] = t;    \
 277     t ^= E_KEY[8 * i + 1]; E_KEY[8 * i + 9] = t;    \
 278     t ^= E_KEY[8 * i + 2]; E_KEY[8 * i + 10] = t;   \
 279     t ^= E_KEY[8 * i + 3]; E_KEY[8 * i + 11] = t;   \
 280     t  = E_KEY[8 * i + 4] ^ ls_box(t);    \
 281     E_KEY[8 * i + 12] = t;                \
 282     t ^= E_KEY[8 * i + 5]; E_KEY[8 * i + 13] = t;   \
 283     t ^= E_KEY[8 * i + 6]; E_KEY[8 * i + 14] = t;   \
 284     t ^= E_KEY[8 * i + 7]; E_KEY[8 * i + 15] = t;   \
 285 }
 286
 287 /* Tells whether the ACE is capable to generate
 288    the extended key for a given key_len. */
 289 static inline int
 290 aes_hw_extkey_available(uint8_t key_len)
 291 {
 292         /* TODO: We should check the actual CPU model/stepping
 293                  as it's possible that the capability will be
 294                  added in the next CPU revisions. */
 295         if (key_len == 16)
 296                 return 1;
 297         return 0;
 298 }
 299
 300 static inline struct aes_ctx *aes_ctx_common(void *ctx)
 301 {
 302         unsigned long addr = (unsigned long)ctx;
 303         unsigned long align = PADLOCK_ALIGNMENT;
 304
 305         if (align <= crypto_tfm_ctx_alignment())
 306                 align = 1;
 307         return (struct aes_ctx *)ALIGN(addr, align);
 308 }
 309
 310 static inline struct aes_ctx *aes_ctx(struct crypto_tfm *tfm)
 311 {
 312         return aes_ctx_common(crypto_tfm_ctx(tfm));
 313 }
 314
 315 static inline struct aes_ctx *blk_aes_ctx(struct crypto_blkcipher *tfm)
 316 {
 317         return aes_ctx_common(crypto_blkcipher_ctx(tfm));
 318 }
 319
 320 static int aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
 321                        unsigned int key_len)
 322 {
 323         struct aes_ctx *ctx = aes_ctx(tfm);
 324         const __le32 *key = (const __le32 *)in_key;
 325         u32 *flags = &tfm->crt_flags;
 326         uint32_t i, t, u, v, w;
 327         uint32_t P[AES_EXTENDED_KEY_SIZE];
 328         uint32_t rounds;
 329
 330         if (key_len % 8) {
 331                 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 332                 return -EINVAL;
 333         }
 334
 335         ctx->key_length = key_len;
 336
 337         /*
 338          * If the hardware is capable of generating the extended key
 339          * itself we must supply the plain key for both encryption
 340          * and decryption.
 341          */
 342         ctx->D = ctx->E;
 343
 344         E_KEY[0] = le32_to_cpu(key[0]);
 345         E_KEY[1] = le32_to_cpu(key[1]);
 346         E_KEY[2] = le32_to_cpu(key[2]);
 347         E_KEY[3] = le32_to_cpu(key[3]);
 348
 349         /* Prepare control words. */
 350         memset(&ctx->cword, 0, sizeof(ctx->cword));
 351
 352         ctx->cword.decrypt.encdec = 1;
 353         ctx->cword.encrypt.rounds = 10 + (key_len - 16) / 4;
 354         ctx->cword.decrypt.rounds = ctx->cword.encrypt.rounds;
 355         ctx->cword.encrypt.ksize = (key_len - 16) / 8;
 356         ctx->cword.decrypt.ksize = ctx->cword.encrypt.ksize;
 357
 358         /* Don't generate extended keys if the hardware can do it. */
 359         if (aes_hw_extkey_available(key_len))
 360                 return 0;
 361
 362         ctx->D = ctx->d_data;
 363         ctx->cword.encrypt.keygen = 1;
 364         ctx->cword.decrypt.keygen = 1;
 365
 366         switch (key_len) {
 367         case 16:
 368                 t = E_KEY[3];
 369                 for (i = 0; i < 10; ++i)
 370                         loop4 (i);
 371                 break;
 372
 373         case 24:
 374                 E_KEY[4] = le32_to_cpu(key[4]);
 375                 t = E_KEY[5] = le32_to_cpu(key[5]);
 376                 for (i = 0; i < 8; ++i)
 377                         loop6 (i);
 378                 break;
 379
 380         case 32:
 381                 E_KEY[4] = le32_to_cpu(key[4]);
 382                 E_KEY[5] = le32_to_cpu(key[5]);
 383                 E_KEY[6] = le32_to_cpu(key[6]);
 384                 t = E_KEY[7] = le32_to_cpu(key[7]);
 385                 for (i = 0; i < 7; ++i)
 386                         loop8 (i);
 387                 break;
 388         }
 389
 390         D_KEY[0] = E_KEY[0];
 391         D_KEY[1] = E_KEY[1];
 392         D_KEY[2] = E_KEY[2];
 393         D_KEY[3] = E_KEY[3];
 394
 395         for (i = 4; i < key_len + 24; ++i) {
 396                 imix_col (D_KEY[i], E_KEY[i]);
 397         }
 398
 399         /* PadLock needs a different format of the decryption key. */
 400         rounds = 10 + (key_len - 16) / 4;
 401
 402         for (i = 0; i < rounds; i++) {
 403                 P[((i + 1) * 4) + 0] = D_KEY[((rounds - i - 1) * 4) + 0];
 404                 P[((i + 1) * 4) + 1] = D_KEY[((rounds - i - 1) * 4) + 1];
 405                 P[((i + 1) * 4) + 2] = D_KEY[((rounds - i - 1) * 4) + 2];
 406                 P[((i + 1) * 4) + 3] = D_KEY[((rounds - i - 1) * 4) + 3];
 407         }
 408
 409         P[0] = E_KEY[(rounds * 4) + 0];
 410         P[1] = E_KEY[(rounds * 4) + 1];
 411         P[2] = E_KEY[(rounds * 4) + 2];
 412         P[3] = E_KEY[(rounds * 4) + 3];
 413
 414         memcpy(D_KEY, P, AES_EXTENDED_KEY_SIZE_B);
 415
 416         return 0;
 417 }
 418
 419 /* ====== Encryption/decryption routines ====== */
 420
 421 /* These are the real call to PadLock. */
 422 static inline void padlock_xcrypt_ecb(const u8 *input, u8 *output, void *key,
 423                                       void *control_word, u32 count)
 424 {
 425         asm volatile ("pushfl; popfl");         /* enforce key reload. */
 426         asm volatile (".byte 0xf3,0x0f,0xa7,0xc8"       /* rep xcryptecb */
 427                       : "+S"(input), "+D"(output)
 428                       : "d"(control_word), "b"(key), "c"(count));
 429 }
 430
 431 static inline u8 *padlock_xcrypt_cbc(const u8 *input, u8 *output, void *key,
 432                                      u8 *iv, void *control_word, u32 count)
 433 {
 434         /* Enforce key reload. */
 435         asm volatile ("pushfl; popfl");
 436         /* rep xcryptcbc */
 437         asm volatile (".byte 0xf3,0x0f,0xa7,0xd0"
 438                       : "+S" (input), "+D" (output), "+a" (iv)
 439                       : "d" (control_word), "b" (key), "c" (count));
 440         return iv;
 441 }
 442
 443 static void aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
 444 {
 445         struct aes_ctx *ctx = aes_ctx(tfm);
 446         padlock_xcrypt_ecb(in, out, ctx->E, &ctx->cword.encrypt, 1);
 447 }
 448
 449 static void aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
 450 {
 451         struct aes_ctx *ctx = aes_ctx(tfm);
 452         padlock_xcrypt_ecb(in, out, ctx->D, &ctx->cword.decrypt, 1);
 453 }
 454
 455 static struct crypto_alg aes_alg = {
 456         .cra_name               =       "aes",
 457         .cra_driver_name        =       "aes-padlock",
 458         .cra_priority           =       PADLOCK_CRA_PRIORITY,
 459         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
 460         .cra_blocksize          =       AES_BLOCK_SIZE,
 461         .cra_ctxsize            =       sizeof(struct aes_ctx),
 462         .cra_alignmask          =       PADLOCK_ALIGNMENT - 1,
 463         .cra_module             =       THIS_MODULE,
 464         .cra_list               =       LIST_HEAD_INIT(aes_alg.cra_list),
 465         .cra_u                  =       {
 466                 .cipher = {
 467                         .cia_min_keysize        =       AES_MIN_KEY_SIZE,
 468                         .cia_max_keysize        =       AES_MAX_KEY_SIZE,
 469                         .cia_setkey             =       aes_set_key,
 470                         .cia_encrypt            =       aes_encrypt,
 471                         .cia_decrypt            =       aes_decrypt,
 472                 }
 473         }
 474 };
 475
 476 static int ecb_aes_encrypt(struct blkcipher_desc *desc,
 477                            struct scatterlist *dst, struct scatterlist *src,
 478                            unsigned int nbytes)
 479 {
 480         struct aes_ctx *ctx = blk_aes_ctx(desc->tfm);
 481         struct blkcipher_walk walk;
 482         int err;
 483
 484         blkcipher_walk_init(&walk, dst, src, nbytes);
 485         err = blkcipher_walk_virt(desc, &walk);
 486
 487         while ((nbytes = walk.nbytes)) {
 488                 padlock_xcrypt_ecb(walk.src.virt.addr, walk.dst.virt.addr,
 489                                    ctx->E, &ctx->cword.encrypt,
 490                                    nbytes / AES_BLOCK_SIZE);
 491                 nbytes &= AES_BLOCK_SIZE - 1;
 492                 err = blkcipher_walk_done(desc, &walk, nbytes);
 493         }
 494
 495         return err;
 496 }
 497
 498 static int ecb_aes_decrypt(struct blkcipher_desc *desc,
 499                            struct scatterlist *dst, struct scatterlist *src,
 500                            unsigned int nbytes)
 501 {
 502         struct aes_ctx *ctx = blk_aes_ctx(desc->tfm);
 503         struct blkcipher_walk walk;
 504         int err;
 505
 506         blkcipher_walk_init(&walk, dst, src, nbytes);
 507         err = blkcipher_walk_virt(desc, &walk);
 508
 509         while ((nbytes = walk.nbytes)) {
 510                 padlock_xcrypt_ecb(walk.src.virt.addr, walk.dst.virt.addr,
 511                                    ctx->D, &ctx->cword.decrypt,
 512                                    nbytes / AES_BLOCK_SIZE);
 513                 nbytes &= AES_BLOCK_SIZE - 1;
 514                 err = blkcipher_walk_done(desc, &walk, nbytes);
 515         }
 516
 517         return err;
 518 }
 519
 520 static struct crypto_alg ecb_aes_alg = {
 521         .cra_name               =       "ecb(aes)",
 522         .cra_driver_name        =       "ecb-aes-padlock",
 523         .cra_priority           =       PADLOCK_COMPOSITE_PRIORITY,
 524         .cra_flags              =       CRYPTO_ALG_TYPE_BLKCIPHER,
 525         .cra_blocksize          =       AES_BLOCK_SIZE,
 526         .cra_ctxsize            =       sizeof(struct aes_ctx),
 527         .cra_alignmask          =       PADLOCK_ALIGNMENT - 1,
 528         .cra_type               =       &crypto_blkcipher_type,
 529         .cra_module             =       THIS_MODULE,
 530         .cra_list               =       LIST_HEAD_INIT(ecb_aes_alg.cra_list),
 531         .cra_u                  =       {
 532                 .blkcipher = {
 533                         .min_keysize            =       AES_MIN_KEY_SIZE,
 534                         .max_keysize            =       AES_MAX_KEY_SIZE,
 535                         .setkey                 =       aes_set_key,
 536                         .encrypt                =       ecb_aes_encrypt,
 537                         .decrypt                =       ecb_aes_decrypt,
 538                 }
 539         }
 540 };
 541
 542 static int cbc_aes_encrypt(struct blkcipher_desc *desc,
 543                            struct scatterlist *dst, struct scatterlist *src,
 544                            unsigned int nbytes)
 545 {
 546         struct aes_ctx *ctx = blk_aes_ctx(desc->tfm);
 547         struct blkcipher_walk walk;
 548         int err;
 549
 550         blkcipher_walk_init(&walk, dst, src, nbytes);
 551         err = blkcipher_walk_virt(desc, &walk);
 552
 553         while ((nbytes = walk.nbytes)) {
 554                 u8 *iv = padlock_xcrypt_cbc(walk.src.virt.addr,
 555                                             walk.dst.virt.addr, ctx->E,
 556                                             walk.iv, &ctx->cword.encrypt,
 557                                             nbytes / AES_BLOCK_SIZE);
 558                 memcpy(walk.iv, iv, AES_BLOCK_SIZE);
 559                 nbytes &= AES_BLOCK_SIZE - 1;
 560                 err = blkcipher_walk_done(desc, &walk, nbytes);
 561         }
 562
 563         return err;
 564 }
 565
 566 static int cbc_aes_decrypt(struct blkcipher_desc *desc,
 567                            struct scatterlist *dst, struct scatterlist *src,
 568                            unsigned int nbytes)
 569 {
 570         struct aes_ctx *ctx = blk_aes_ctx(desc->tfm);
 571         struct blkcipher_walk walk;
 572         int err;
 573
 574         blkcipher_walk_init(&walk, dst, src, nbytes);
 575         err = blkcipher_walk_virt(desc, &walk);
 576
 577         while ((nbytes = walk.nbytes)) {
 578                 padlock_xcrypt_cbc(walk.src.virt.addr, walk.dst.virt.addr,
 579                                    ctx->D, walk.iv, &ctx->cword.decrypt,
 580                                    nbytes / AES_BLOCK_SIZE);
 581                 nbytes &= AES_BLOCK_SIZE - 1;
 582                 err = blkcipher_walk_done(desc, &walk, nbytes);
 583         }
 584
 585         return err;
 586 }
 587
 588 static struct crypto_alg cbc_aes_alg = {
 589         .cra_name               =       "cbc(aes)",
 590         .cra_driver_name        =       "cbc-aes-padlock",
 591         .cra_priority           =       PADLOCK_COMPOSITE_PRIORITY,
 592         .cra_flags              =       CRYPTO_ALG_TYPE_BLKCIPHER,
 593         .cra_blocksize          =       AES_BLOCK_SIZE,
 594         .cra_ctxsize            =       sizeof(struct aes_ctx),
 595         .cra_alignmask          =       PADLOCK_ALIGNMENT - 1,
 596         .cra_type               =       &crypto_blkcipher_type,
 597         .cra_module             =       THIS_MODULE,
 598         .cra_list               =       LIST_HEAD_INIT(cbc_aes_alg.cra_list),
 599         .cra_u                  =       {
 600                 .blkcipher = {
 601                         .min_keysize            =       AES_MIN_KEY_SIZE,
 602                         .max_keysize            =       AES_MAX_KEY_SIZE,
 603                         .ivsize                 =       AES_BLOCK_SIZE,
 604                         .setkey                 =       aes_set_key,
 605                         .encrypt                =       cbc_aes_encrypt,
 606                         .decrypt                =       cbc_aes_decrypt,
 607                 }
 608         }
 609 };
 610
 611 static int __init padlock_init(void)
 612 {
 613         int ret;
 614
 615         if (!cpu_has_xcrypt) {
 616                 printk(KERN_ERR PFX "VIA PadLock not detected.\n");
 617                 return -ENODEV;
 618         }
 619
 620         if (!cpu_has_xcrypt_enabled) {
 621                 printk(KERN_ERR PFX "VIA PadLock detected, but not enabled. Hmm, strange...\n");
 622                 return -ENODEV;
 623         }
 624
 625         gen_tabs();
 626         if ((ret = crypto_register_alg(&aes_alg)))
 627                 goto aes_err;
 628
 629         if ((ret = crypto_register_alg(&ecb_aes_alg)))
 630                 goto ecb_aes_err;
 631
 632         if ((ret = crypto_register_alg(&cbc_aes_alg)))
 633                 goto cbc_aes_err;
 634
 635         printk(KERN_NOTICE PFX "Using VIA PadLock ACE for AES algorithm.\n");
 636
 637 out:
 638         return ret;
 639
 640 cbc_aes_err:
 641         crypto_unregister_alg(&ecb_aes_alg);
 642 ecb_aes_err:
 643         crypto_unregister_alg(&aes_alg);
 644 aes_err:
 645         printk(KERN_ERR PFX "VIA PadLock AES initialization failed.\n");
 646         goto out;
 647 }
 648
 649 static void __exit padlock_fini(void)
 650 {
 651         crypto_unregister_alg(&cbc_aes_alg);
 652         crypto_unregister_alg(&ecb_aes_alg);
 653         crypto_unregister_alg(&aes_alg);
 654 }
 655
 656 module_init(padlock_init);
 657 module_exit(padlock_fini);
 658
 659 MODULE_DESCRIPTION("VIA PadLock AES algorithm support");
 660 MODULE_LICENSE("GPL");
 661 MODULE_AUTHOR("Michal Ludvig");
 662
 663 MODULE_ALIAS("aes-padlock");