drivers/crypto/padlock-aes.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Cryptographic API.
   4  *
   5  * Support for VIA PadLock hardware crypto engine.
   6  *
   7  * Copyright (c) 2004  Michal Ludvig <michal@logix.cz>
   8  *
   9  */
  10
  11 #include <crypto/algapi.h>
  12 #include <crypto/aes.h>
  13 #include <crypto/padlock.h>
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/types.h>
  17 #include <linux/errno.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/kernel.h>
  20 #include <linux/percpu.h>
  21 #include <linux/smp.h>
  22 #include <linux/slab.h>
  23 #include <asm/cpu_device_id.h>
  24 #include <asm/byteorder.h>
  25 #include <asm/processor.h>
  26 #include <asm/fpu/api.h>
  27
  28 /*
  29  * Number of data blocks actually fetched for each xcrypt insn.
  30  * Processors with prefetch errata will fetch extra blocks.
  31  */
  32 static unsigned int ecb_fetch_blocks = 2;
  33 #define MAX_ECB_FETCH_BLOCKS (8)
  34 #define ecb_fetch_bytes (ecb_fetch_blocks * AES_BLOCK_SIZE)
  35
  36 static unsigned int cbc_fetch_blocks = 1;
  37 #define MAX_CBC_FETCH_BLOCKS (4)
  38 #define cbc_fetch_bytes (cbc_fetch_blocks * AES_BLOCK_SIZE)
  39
  40 /* Control word. */
  41 struct cword {
  42         unsigned int __attribute__ ((__packed__))
  43                 rounds:4,
  44                 algo:3,
  45                 keygen:1,
  46                 interm:1,
  47                 encdec:1,
  48                 ksize:2;
  49 } __attribute__ ((__aligned__(PADLOCK_ALIGNMENT)));
  50
  51 /* Whenever making any changes to the following
  52  * structure *make sure* you keep E, d_data
  53  * and cword aligned on 16 Bytes boundaries and
  54  * the Hardware can access 16 * 16 bytes of E and d_data
  55  * (only the first 15 * 16 bytes matter but the HW reads
  56  * more).
  57  */
  58 struct aes_ctx {
  59         u32 E[AES_MAX_KEYLENGTH_U32]
  60                 __attribute__ ((__aligned__(PADLOCK_ALIGNMENT)));
  61         u32 d_data[AES_MAX_KEYLENGTH_U32]
  62                 __attribute__ ((__aligned__(PADLOCK_ALIGNMENT)));
  63         struct {
  64                 struct cword encrypt;
  65                 struct cword decrypt;
  66         } cword;
  67         u32 *D;
  68 };
  69
  70 static DEFINE_PER_CPU(struct cword *, paes_last_cword);
  71
  72 /* Tells whether the ACE is capable to generate
  73    the extended key for a given key_len. */
  74 static inline int
  75 aes_hw_extkey_available(uint8_t key_len)
  76 {
  77         /* TODO: We should check the actual CPU model/stepping
  78                  as it's possible that the capability will be
  79                  added in the next CPU revisions. */
  80         if (key_len == 16)
  81                 return 1;
  82         return 0;
  83 }
  84
  85 static inline struct aes_ctx *aes_ctx_common(void *ctx)
  86 {
  87         unsigned long addr = (unsigned long)ctx;
  88         unsigned long align = PADLOCK_ALIGNMENT;
  89
  90         if (align <= crypto_tfm_ctx_alignment())
  91                 align = 1;
  92         return (struct aes_ctx *)ALIGN(addr, align);
  93 }
  94
  95 static inline struct aes_ctx *aes_ctx(struct crypto_tfm *tfm)
  96 {
  97         return aes_ctx_common(crypto_tfm_ctx(tfm));
  98 }
  99
 100 static inline struct aes_ctx *blk_aes_ctx(struct crypto_blkcipher *tfm)
 101 {
 102         return aes_ctx_common(crypto_blkcipher_ctx(tfm));
 103 }
 104
 105 static int aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
 106                        unsigned int key_len)
 107 {
 108         struct aes_ctx *ctx = aes_ctx(tfm);
 109         const __le32 *key = (const __le32 *)in_key;
 110         u32 *flags = &tfm->crt_flags;
 111         struct crypto_aes_ctx gen_aes;
 112         int cpu;
 113
 114         if (key_len % 8) {
 115                 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 116                 return -EINVAL;
 117         }
 118
 119         /*
 120          * If the hardware is capable of generating the extended key
 121          * itself we must supply the plain key for both encryption
 122          * and decryption.
 123          */
 124         ctx->D = ctx->E;
 125
 126         ctx->E[0] = le32_to_cpu(key[0]);
 127         ctx->E[1] = le32_to_cpu(key[1]);
 128         ctx->E[2] = le32_to_cpu(key[2]);
 129         ctx->E[3] = le32_to_cpu(key[3]);
 130
 131         /* Prepare control words. */
 132         memset(&ctx->cword, 0, sizeof(ctx->cword));
 133
 134         ctx->cword.decrypt.encdec = 1;
 135         ctx->cword.encrypt.rounds = 10 + (key_len - 16) / 4;
 136         ctx->cword.decrypt.rounds = ctx->cword.encrypt.rounds;
 137         ctx->cword.encrypt.ksize = (key_len - 16) / 8;
 138         ctx->cword.decrypt.ksize = ctx->cword.encrypt.ksize;
 139
 140         /* Don't generate extended keys if the hardware can do it. */
 141         if (aes_hw_extkey_available(key_len))
 142                 goto ok;
 143
 144         ctx->D = ctx->d_data;
 145         ctx->cword.encrypt.keygen = 1;
 146         ctx->cword.decrypt.keygen = 1;
 147
 148         if (aes_expandkey(&gen_aes, in_key, key_len)) {
 149                 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 150                 return -EINVAL;
 151         }
 152
 153         memcpy(ctx->E, gen_aes.key_enc, AES_MAX_KEYLENGTH);
 154         memcpy(ctx->D, gen_aes.key_dec, AES_MAX_KEYLENGTH);
 155
 156 ok:
 157         for_each_online_cpu(cpu)
 158                 if (&ctx->cword.encrypt == per_cpu(paes_last_cword, cpu) ||
 159                     &ctx->cword.decrypt == per_cpu(paes_last_cword, cpu))
 160                         per_cpu(paes_last_cword, cpu) = NULL;
 161
 162         return 0;
 163 }
 164
 165 /* ====== Encryption/decryption routines ====== */
 166
 167 /* These are the real call to PadLock. */
 168 static inline void padlock_reset_key(struct cword *cword)
 169 {
 170         int cpu = raw_smp_processor_id();
 171
 172         if (cword != per_cpu(paes_last_cword, cpu))
 173 #ifndef CONFIG_X86_64
 174                 asm volatile ("pushfl; popfl");
 175 #else
 176                 asm volatile ("pushfq; popfq");
 177 #endif
 178 }
 179
 180 static inline void padlock_store_cword(struct cword *cword)
 181 {
 182         per_cpu(paes_last_cword, raw_smp_processor_id()) = cword;
 183 }
 184
 185 /*
 186  * While the padlock instructions don't use FP/SSE registers, they
 187  * generate a spurious DNA fault when CR0.TS is '1'.  Fortunately,
 188  * the kernel doesn't use CR0.TS.
 189  */
 190
 191 static inline void rep_xcrypt_ecb(const u8 *input, u8 *output, void *key,
 192                                   struct cword *control_word, int count)
 193 {
 194         asm volatile (".byte 0xf3,0x0f,0xa7,0xc8"       /* rep xcryptecb */
 195                       : "+S"(input), "+D"(output)
 196                       : "d"(control_word), "b"(key), "c"(count));
 197 }
 198
 199 static inline u8 *rep_xcrypt_cbc(const u8 *input, u8 *output, void *key,
 200                                  u8 *iv, struct cword *control_word, int count)
 201 {
 202         asm volatile (".byte 0xf3,0x0f,0xa7,0xd0"       /* rep xcryptcbc */
 203                       : "+S" (input), "+D" (output), "+a" (iv)
 204                       : "d" (control_word), "b" (key), "c" (count));
 205         return iv;
 206 }
 207
 208 static void ecb_crypt_copy(const u8 *in, u8 *out, u32 *key,
 209                            struct cword *cword, int count)
 210 {
 211         /*
 212          * Padlock prefetches extra data so we must provide mapped input buffers.
 213          * Assume there are at least 16 bytes of stack already in use.
 214          */
 215         u8 buf[AES_BLOCK_SIZE * (MAX_ECB_FETCH_BLOCKS - 1) + PADLOCK_ALIGNMENT - 1];
 216         u8 *tmp = PTR_ALIGN(&buf[0], PADLOCK_ALIGNMENT);
 217
 218         memcpy(tmp, in, count * AES_BLOCK_SIZE);
 219         rep_xcrypt_ecb(tmp, out, key, cword, count);
 220 }
 221
 222 static u8 *cbc_crypt_copy(const u8 *in, u8 *out, u32 *key,
 223                            u8 *iv, struct cword *cword, int count)
 224 {
 225         /*
 226          * Padlock prefetches extra data so we must provide mapped input buffers.
 227          * Assume there are at least 16 bytes of stack already in use.
 228          */
 229         u8 buf[AES_BLOCK_SIZE * (MAX_CBC_FETCH_BLOCKS - 1) + PADLOCK_ALIGNMENT - 1];
 230         u8 *tmp = PTR_ALIGN(&buf[0], PADLOCK_ALIGNMENT);
 231
 232         memcpy(tmp, in, count * AES_BLOCK_SIZE);
 233         return rep_xcrypt_cbc(tmp, out, key, iv, cword, count);
 234 }
 235
 236 static inline void ecb_crypt(const u8 *in, u8 *out, u32 *key,
 237                              struct cword *cword, int count)
 238 {
 239         /* Padlock in ECB mode fetches at least ecb_fetch_bytes of data.
 240          * We could avoid some copying here but it's probably not worth it.
 241          */
 242         if (unlikely(offset_in_page(in) + ecb_fetch_bytes > PAGE_SIZE)) {
 243                 ecb_crypt_copy(in, out, key, cword, count);
 244                 return;
 245         }
 246
 247         rep_xcrypt_ecb(in, out, key, cword, count);
 248 }
 249
 250 static inline u8 *cbc_crypt(const u8 *in, u8 *out, u32 *key,
 251                             u8 *iv, struct cword *cword, int count)
 252 {
 253         /* Padlock in CBC mode fetches at least cbc_fetch_bytes of data. */
 254         if (unlikely(offset_in_page(in) + cbc_fetch_bytes > PAGE_SIZE))
 255                 return cbc_crypt_copy(in, out, key, iv, cword, count);
 256
 257         return rep_xcrypt_cbc(in, out, key, iv, cword, count);
 258 }
 259
 260 static inline void padlock_xcrypt_ecb(const u8 *input, u8 *output, void *key,
 261                                       void *control_word, u32 count)
 262 {
 263         u32 initial = count & (ecb_fetch_blocks - 1);
 264
 265         if (count < ecb_fetch_blocks) {
 266                 ecb_crypt(input, output, key, control_word, count);
 267                 return;
 268         }
 269
 270         count -= initial;
 271
 272         if (initial)
 273                 asm volatile (".byte 0xf3,0x0f,0xa7,0xc8"       /* rep xcryptecb */
 274                               : "+S"(input), "+D"(output)
 275                               : "d"(control_word), "b"(key), "c"(initial));
 276
 277         asm volatile (".byte 0xf3,0x0f,0xa7,0xc8"       /* rep xcryptecb */
 278                       : "+S"(input), "+D"(output)
 279                       : "d"(control_word), "b"(key), "c"(count));
 280 }
 281
 282 static inline u8 *padlock_xcrypt_cbc(const u8 *input, u8 *output, void *key,
 283                                      u8 *iv, void *control_word, u32 count)
 284 {
 285         u32 initial = count & (cbc_fetch_blocks - 1);
 286
 287         if (count < cbc_fetch_blocks)
 288                 return cbc_crypt(input, output, key, iv, control_word, count);
 289
 290         count -= initial;
 291
 292         if (initial)
 293                 asm volatile (".byte 0xf3,0x0f,0xa7,0xd0"       /* rep xcryptcbc */
 294                               : "+S" (input), "+D" (output), "+a" (iv)
 295                               : "d" (control_word), "b" (key), "c" (initial));
 296
 297         asm volatile (".byte 0xf3,0x0f,0xa7,0xd0"       /* rep xcryptcbc */
 298                       : "+S" (input), "+D" (output), "+a" (iv)
 299                       : "d" (control_word), "b" (key), "c" (count));
 300         return iv;
 301 }
 302
 303 static void padlock_aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
 304 {
 305         struct aes_ctx *ctx = aes_ctx(tfm);
 306
 307         padlock_reset_key(&ctx->cword.encrypt);
 308         ecb_crypt(in, out, ctx->E, &ctx->cword.encrypt, 1);
 309         padlock_store_cword(&ctx->cword.encrypt);
 310 }
 311
 312 static void padlock_aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
 313 {
 314         struct aes_ctx *ctx = aes_ctx(tfm);
 315
 316         padlock_reset_key(&ctx->cword.encrypt);
 317         ecb_crypt(in, out, ctx->D, &ctx->cword.decrypt, 1);
 318         padlock_store_cword(&ctx->cword.encrypt);
 319 }
 320
 321 static struct crypto_alg aes_alg = {
 322         .cra_name               =       "aes",
 323         .cra_driver_name        =       "aes-padlock",
 324         .cra_priority           =       PADLOCK_CRA_PRIORITY,
 325         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
 326         .cra_blocksize          =       AES_BLOCK_SIZE,
 327         .cra_ctxsize            =       sizeof(struct aes_ctx),
 328         .cra_alignmask          =       PADLOCK_ALIGNMENT - 1,
 329         .cra_module             =       THIS_MODULE,
 330         .cra_u                  =       {
 331                 .cipher = {
 332                         .cia_min_keysize        =       AES_MIN_KEY_SIZE,
 333                         .cia_max_keysize        =       AES_MAX_KEY_SIZE,
 334                         .cia_setkey             =       aes_set_key,
 335                         .cia_encrypt            =       padlock_aes_encrypt,
 336                         .cia_decrypt            =       padlock_aes_decrypt,
 337                 }
 338         }
 339 };
 340
 341 static int ecb_aes_encrypt(struct blkcipher_desc *desc,
 342                            struct scatterlist *dst, struct scatterlist *src,
 343                            unsigned int nbytes)
 344 {
 345         struct aes_ctx *ctx = blk_aes_ctx(desc->tfm);
 346         struct blkcipher_walk walk;
 347         int err;
 348
 349         padlock_reset_key(&ctx->cword.encrypt);
 350
 351         blkcipher_walk_init(&walk, dst, src, nbytes);
 352         err = blkcipher_walk_virt(desc, &walk);
 353
 354         while ((nbytes = walk.nbytes)) {
 355                 padlock_xcrypt_ecb(walk.src.virt.addr, walk.dst.virt.addr,
 356                                    ctx->E, &ctx->cword.encrypt,
 357                                    nbytes / AES_BLOCK_SIZE);
 358                 nbytes &= AES_BLOCK_SIZE - 1;
 359                 err = blkcipher_walk_done(desc, &walk, nbytes);
 360         }
 361
 362         padlock_store_cword(&ctx->cword.encrypt);
 363
 364         return err;
 365 }
 366
 367 static int ecb_aes_decrypt(struct blkcipher_desc *desc,
 368                            struct scatterlist *dst, struct scatterlist *src,
 369                            unsigned int nbytes)
 370 {
 371         struct aes_ctx *ctx = blk_aes_ctx(desc->tfm);
 372         struct blkcipher_walk walk;
 373         int err;
 374
 375         padlock_reset_key(&ctx->cword.decrypt);
 376
 377         blkcipher_walk_init(&walk, dst, src, nbytes);
 378         err = blkcipher_walk_virt(desc, &walk);
 379
 380         while ((nbytes = walk.nbytes)) {
 381                 padlock_xcrypt_ecb(walk.src.virt.addr, walk.dst.virt.addr,
 382                                    ctx->D, &ctx->cword.decrypt,
 383                                    nbytes / AES_BLOCK_SIZE);
 384                 nbytes &= AES_BLOCK_SIZE - 1;
 385                 err = blkcipher_walk_done(desc, &walk, nbytes);
 386         }
 387
 388         padlock_store_cword(&ctx->cword.encrypt);
 389
 390         return err;
 391 }
 392
 393 static struct crypto_alg ecb_aes_alg = {
 394         .cra_name               =       "ecb(aes)",
 395         .cra_driver_name        =       "ecb-aes-padlock",
 396         .cra_priority           =       PADLOCK_COMPOSITE_PRIORITY,
 397         .cra_flags              =       CRYPTO_ALG_TYPE_BLKCIPHER,
 398         .cra_blocksize          =       AES_BLOCK_SIZE,
 399         .cra_ctxsize            =       sizeof(struct aes_ctx),
 400         .cra_alignmask          =       PADLOCK_ALIGNMENT - 1,
 401         .cra_type               =       &crypto_blkcipher_type,
 402         .cra_module             =       THIS_MODULE,
 403         .cra_u                  =       {
 404                 .blkcipher = {
 405                         .min_keysize            =       AES_MIN_KEY_SIZE,
 406                         .max_keysize            =       AES_MAX_KEY_SIZE,
 407                         .setkey                 =       aes_set_key,
 408                         .encrypt                =       ecb_aes_encrypt,
 409                         .decrypt                =       ecb_aes_decrypt,
 410                 }
 411         }
 412 };
 413
 414 static int cbc_aes_encrypt(struct blkcipher_desc *desc,
 415                            struct scatterlist *dst, struct scatterlist *src,
 416                            unsigned int nbytes)
 417 {
 418         struct aes_ctx *ctx = blk_aes_ctx(desc->tfm);
 419         struct blkcipher_walk walk;
 420         int err;
 421
 422         padlock_reset_key(&ctx->cword.encrypt);
 423
 424         blkcipher_walk_init(&walk, dst, src, nbytes);
 425         err = blkcipher_walk_virt(desc, &walk);
 426
 427         while ((nbytes = walk.nbytes)) {
 428                 u8 *iv = padlock_xcrypt_cbc(walk.src.virt.addr,
 429                                             walk.dst.virt.addr, ctx->E,
 430                                             walk.iv, &ctx->cword.encrypt,
 431                                             nbytes / AES_BLOCK_SIZE);
 432                 memcpy(walk.iv, iv, AES_BLOCK_SIZE);
 433                 nbytes &= AES_BLOCK_SIZE - 1;
 434                 err = blkcipher_walk_done(desc, &walk, nbytes);
 435         }
 436
 437         padlock_store_cword(&ctx->cword.decrypt);
 438
 439         return err;
 440 }
 441
 442 static int cbc_aes_decrypt(struct blkcipher_desc *desc,
 443                            struct scatterlist *dst, struct scatterlist *src,
 444                            unsigned int nbytes)
 445 {
 446         struct aes_ctx *ctx = blk_aes_ctx(desc->tfm);
 447         struct blkcipher_walk walk;
 448         int err;
 449
 450         padlock_reset_key(&ctx->cword.encrypt);
 451
 452         blkcipher_walk_init(&walk, dst, src, nbytes);
 453         err = blkcipher_walk_virt(desc, &walk);
 454
 455         while ((nbytes = walk.nbytes)) {
 456                 padlock_xcrypt_cbc(walk.src.virt.addr, walk.dst.virt.addr,
 457                                    ctx->D, walk.iv, &ctx->cword.decrypt,
 458                                    nbytes / AES_BLOCK_SIZE);
 459                 nbytes &= AES_BLOCK_SIZE - 1;
 460                 err = blkcipher_walk_done(desc, &walk, nbytes);
 461         }
 462
 463         padlock_store_cword(&ctx->cword.encrypt);
 464
 465         return err;
 466 }
 467
 468 static struct crypto_alg cbc_aes_alg = {
 469         .cra_name               =       "cbc(aes)",
 470         .cra_driver_name        =       "cbc-aes-padlock",
 471         .cra_priority           =       PADLOCK_COMPOSITE_PRIORITY,
 472         .cra_flags              =       CRYPTO_ALG_TYPE_BLKCIPHER,
 473         .cra_blocksize          =       AES_BLOCK_SIZE,
 474         .cra_ctxsize            =       sizeof(struct aes_ctx),
 475         .cra_alignmask          =       PADLOCK_ALIGNMENT - 1,
 476         .cra_type               =       &crypto_blkcipher_type,
 477         .cra_module             =       THIS_MODULE,
 478         .cra_u                  =       {
 479                 .blkcipher = {
 480                         .min_keysize            =       AES_MIN_KEY_SIZE,
 481                         .max_keysize            =       AES_MAX_KEY_SIZE,
 482                         .ivsize                 =       AES_BLOCK_SIZE,
 483                         .setkey                 =       aes_set_key,
 484                         .encrypt                =       cbc_aes_encrypt,
 485                         .decrypt                =       cbc_aes_decrypt,
 486                 }
 487         }
 488 };
 489
 490 static const struct x86_cpu_id padlock_cpu_id[] = {
 491         X86_FEATURE_MATCH(X86_FEATURE_XCRYPT),
 492         {}
 493 };
 494 MODULE_DEVICE_TABLE(x86cpu, padlock_cpu_id);
 495
 496 static int __init padlock_init(void)
 497 {
 498         int ret;
 499         struct cpuinfo_x86 *c = &cpu_data(0);
 500
 501         if (!x86_match_cpu(padlock_cpu_id))
 502                 return -ENODEV;
 503
 504         if (!boot_cpu_has(X86_FEATURE_XCRYPT_EN)) {
 505                 printk(KERN_NOTICE PFX "VIA PadLock detected, but not enabled. Hmm, strange...\n");
 506                 return -ENODEV;
 507         }
 508
 509         if ((ret = crypto_register_alg(&aes_alg)))
 510                 goto aes_err;
 511
 512         if ((ret = crypto_register_alg(&ecb_aes_alg)))
 513                 goto ecb_aes_err;
 514
 515         if ((ret = crypto_register_alg(&cbc_aes_alg)))
 516                 goto cbc_aes_err;
 517
 518         printk(KERN_NOTICE PFX "Using VIA PadLock ACE for AES algorithm.\n");
 519
 520         if (c->x86 == 6 && c->x86_model == 15 && c->x86_stepping == 2) {
 521                 ecb_fetch_blocks = MAX_ECB_FETCH_BLOCKS;
 522                 cbc_fetch_blocks = MAX_CBC_FETCH_BLOCKS;
 523                 printk(KERN_NOTICE PFX "VIA Nano stepping 2 detected: enabling workaround.\n");
 524         }
 525
 526 out:
 527         return ret;
 528
 529 cbc_aes_err:
 530         crypto_unregister_alg(&ecb_aes_alg);
 531 ecb_aes_err:
 532         crypto_unregister_alg(&aes_alg);
 533 aes_err:
 534         printk(KERN_ERR PFX "VIA PadLock AES initialization failed.\n");
 535         goto out;
 536 }
 537
 538 static void __exit padlock_fini(void)
 539 {
 540         crypto_unregister_alg(&cbc_aes_alg);
 541         crypto_unregister_alg(&ecb_aes_alg);
 542         crypto_unregister_alg(&aes_alg);
 543 }
 544
 545 module_init(padlock_init);
 546 module_exit(padlock_fini);
 547
 548 MODULE_DESCRIPTION("VIA PadLock AES algorithm support");
 549 MODULE_LICENSE("GPL");
 550 MODULE_AUTHOR("Michal Ludvig");
 551
 552 MODULE_ALIAS_CRYPTO("aes");