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