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/mm.h> 22 #include <linux/percpu.h> 23 #include <linux/smp.h> 24 #include <linux/slab.h> 25 #include <asm/cpu_device_id.h> 26 #include <asm/byteorder.h> 27 #include <asm/processor.h> 28 #include <asm/fpu/api.h> 29 30 /* 31 * Number of data blocks actually fetched for each xcrypt insn. 32 * Processors with prefetch errata will fetch extra blocks. 33 */ 34 static unsigned int ecb_fetch_blocks = 2; 35 #define MAX_ECB_FETCH_BLOCKS (8) 36 #define ecb_fetch_bytes (ecb_fetch_blocks * AES_BLOCK_SIZE) 37 38 static unsigned int cbc_fetch_blocks = 1; 39 #define MAX_CBC_FETCH_BLOCKS (4) 40 #define cbc_fetch_bytes (cbc_fetch_blocks * AES_BLOCK_SIZE) 41 42 /* Control word. */ 43 struct cword { 44 unsigned int __attribute__ ((__packed__)) 45 rounds:4, 46 algo:3, 47 keygen:1, 48 interm:1, 49 encdec:1, 50 ksize:2; 51 } __attribute__ ((__aligned__(PADLOCK_ALIGNMENT))); 52 53 /* Whenever making any changes to the following 54 * structure *make sure* you keep E, d_data 55 * and cword aligned on 16 Bytes boundaries and 56 * the Hardware can access 16 * 16 bytes of E and d_data 57 * (only the first 15 * 16 bytes matter but the HW reads 58 * more). 59 */ 60 struct aes_ctx { 61 u32 E[AES_MAX_KEYLENGTH_U32] 62 __attribute__ ((__aligned__(PADLOCK_ALIGNMENT))); 63 u32 d_data[AES_MAX_KEYLENGTH_U32] 64 __attribute__ ((__aligned__(PADLOCK_ALIGNMENT))); 65 struct { 66 struct cword encrypt; 67 struct cword decrypt; 68 } cword; 69 u32 *D; 70 }; 71 72 static DEFINE_PER_CPU(struct cword *, paes_last_cword); 73 74 /* Tells whether the ACE is capable to generate 75 the extended key for a given key_len. */ 76 static inline int 77 aes_hw_extkey_available(uint8_t key_len) 78 { 79 /* TODO: We should check the actual CPU model/stepping 80 as it's possible that the capability will be 81 added in the next CPU revisions. */ 82 if (key_len == 16) 83 return 1; 84 return 0; 85 } 86 87 static inline struct aes_ctx *aes_ctx_common(void *ctx) 88 { 89 unsigned long addr = (unsigned long)ctx; 90 unsigned long align = PADLOCK_ALIGNMENT; 91 92 if (align <= crypto_tfm_ctx_alignment()) 93 align = 1; 94 return (struct aes_ctx *)ALIGN(addr, align); 95 } 96 97 static inline struct aes_ctx *aes_ctx(struct crypto_tfm *tfm) 98 { 99 return aes_ctx_common(crypto_tfm_ctx(tfm)); 100 } 101 102 static inline struct aes_ctx *skcipher_aes_ctx(struct crypto_skcipher *tfm) 103 { 104 return aes_ctx_common(crypto_skcipher_ctx(tfm)); 105 } 106 107 static int aes_set_key(struct crypto_tfm *tfm, const u8 *in_key, 108 unsigned int key_len) 109 { 110 struct aes_ctx *ctx = aes_ctx(tfm); 111 const __le32 *key = (const __le32 *)in_key; 112 struct crypto_aes_ctx gen_aes; 113 int cpu; 114 115 if (key_len % 8) 116 return -EINVAL; 117 118 /* 119 * If the hardware is capable of generating the extended key 120 * itself we must supply the plain key for both encryption 121 * and decryption. 122 */ 123 ctx->D = ctx->E; 124 125 ctx->E[0] = le32_to_cpu(key[0]); 126 ctx->E[1] = le32_to_cpu(key[1]); 127 ctx->E[2] = le32_to_cpu(key[2]); 128 ctx->E[3] = le32_to_cpu(key[3]); 129 130 /* Prepare control words. */ 131 memset(&ctx->cword, 0, sizeof(ctx->cword)); 132 133 ctx->cword.decrypt.encdec = 1; 134 ctx->cword.encrypt.rounds = 10 + (key_len - 16) / 4; 135 ctx->cword.decrypt.rounds = ctx->cword.encrypt.rounds; 136 ctx->cword.encrypt.ksize = (key_len - 16) / 8; 137 ctx->cword.decrypt.ksize = ctx->cword.encrypt.ksize; 138 139 /* Don't generate extended keys if the hardware can do it. */ 140 if (aes_hw_extkey_available(key_len)) 141 goto ok; 142 143 ctx->D = ctx->d_data; 144 ctx->cword.encrypt.keygen = 1; 145 ctx->cword.decrypt.keygen = 1; 146 147 if (aes_expandkey(&gen_aes, in_key, key_len)) 148 return -EINVAL; 149 150 memcpy(ctx->E, gen_aes.key_enc, AES_MAX_KEYLENGTH); 151 memcpy(ctx->D, gen_aes.key_dec, AES_MAX_KEYLENGTH); 152 153 ok: 154 for_each_online_cpu(cpu) 155 if (&ctx->cword.encrypt == per_cpu(paes_last_cword, cpu) || 156 &ctx->cword.decrypt == per_cpu(paes_last_cword, cpu)) 157 per_cpu(paes_last_cword, cpu) = NULL; 158 159 return 0; 160 } 161 162 static int aes_set_key_skcipher(struct crypto_skcipher *tfm, const u8 *in_key, 163 unsigned int key_len) 164 { 165 return aes_set_key(crypto_skcipher_tfm(tfm), in_key, key_len); 166 } 167 168 /* ====== Encryption/decryption routines ====== */ 169 170 /* These are the real call to PadLock. */ 171 static inline void padlock_reset_key(struct cword *cword) 172 { 173 int cpu = raw_smp_processor_id(); 174 175 if (cword != per_cpu(paes_last_cword, cpu)) 176 #ifndef CONFIG_X86_64 177 asm volatile ("pushfl; popfl"); 178 #else 179 asm volatile ("pushfq; popfq"); 180 #endif 181 } 182 183 static inline void padlock_store_cword(struct cword *cword) 184 { 185 per_cpu(paes_last_cword, raw_smp_processor_id()) = cword; 186 } 187 188 /* 189 * While the padlock instructions don't use FP/SSE registers, they 190 * generate a spurious DNA fault when CR0.TS is '1'. Fortunately, 191 * the kernel doesn't use CR0.TS. 192 */ 193 194 static inline void rep_xcrypt_ecb(const u8 *input, u8 *output, void *key, 195 struct cword *control_word, int count) 196 { 197 asm volatile (".byte 0xf3,0x0f,0xa7,0xc8" /* rep xcryptecb */ 198 : "+S"(input), "+D"(output) 199 : "d"(control_word), "b"(key), "c"(count)); 200 } 201 202 static inline u8 *rep_xcrypt_cbc(const u8 *input, u8 *output, void *key, 203 u8 *iv, struct cword *control_word, int count) 204 { 205 asm volatile (".byte 0xf3,0x0f,0xa7,0xd0" /* rep xcryptcbc */ 206 : "+S" (input), "+D" (output), "+a" (iv) 207 : "d" (control_word), "b" (key), "c" (count)); 208 return iv; 209 } 210 211 static void ecb_crypt_copy(const u8 *in, u8 *out, u32 *key, 212 struct cword *cword, int count) 213 { 214 /* 215 * Padlock prefetches extra data so we must provide mapped input buffers. 216 * Assume there are at least 16 bytes of stack already in use. 217 */ 218 u8 buf[AES_BLOCK_SIZE * (MAX_ECB_FETCH_BLOCKS - 1) + PADLOCK_ALIGNMENT - 1]; 219 u8 *tmp = PTR_ALIGN(&buf[0], PADLOCK_ALIGNMENT); 220 221 memcpy(tmp, in, count * AES_BLOCK_SIZE); 222 rep_xcrypt_ecb(tmp, out, key, cword, count); 223 } 224 225 static u8 *cbc_crypt_copy(const u8 *in, u8 *out, u32 *key, 226 u8 *iv, struct cword *cword, int count) 227 { 228 /* 229 * Padlock prefetches extra data so we must provide mapped input buffers. 230 * Assume there are at least 16 bytes of stack already in use. 231 */ 232 u8 buf[AES_BLOCK_SIZE * (MAX_CBC_FETCH_BLOCKS - 1) + PADLOCK_ALIGNMENT - 1]; 233 u8 *tmp = PTR_ALIGN(&buf[0], PADLOCK_ALIGNMENT); 234 235 memcpy(tmp, in, count * AES_BLOCK_SIZE); 236 return rep_xcrypt_cbc(tmp, out, key, iv, cword, count); 237 } 238 239 static inline void ecb_crypt(const u8 *in, u8 *out, u32 *key, 240 struct cword *cword, int count) 241 { 242 /* Padlock in ECB mode fetches at least ecb_fetch_bytes of data. 243 * We could avoid some copying here but it's probably not worth it. 244 */ 245 if (unlikely(offset_in_page(in) + ecb_fetch_bytes > PAGE_SIZE)) { 246 ecb_crypt_copy(in, out, key, cword, count); 247 return; 248 } 249 250 rep_xcrypt_ecb(in, out, key, cword, count); 251 } 252 253 static inline u8 *cbc_crypt(const u8 *in, u8 *out, u32 *key, 254 u8 *iv, struct cword *cword, int count) 255 { 256 /* Padlock in CBC mode fetches at least cbc_fetch_bytes of data. */ 257 if (unlikely(offset_in_page(in) + cbc_fetch_bytes > PAGE_SIZE)) 258 return cbc_crypt_copy(in, out, key, iv, cword, count); 259 260 return rep_xcrypt_cbc(in, out, key, iv, cword, count); 261 } 262 263 static inline void padlock_xcrypt_ecb(const u8 *input, u8 *output, void *key, 264 void *control_word, u32 count) 265 { 266 u32 initial = count & (ecb_fetch_blocks - 1); 267 268 if (count < ecb_fetch_blocks) { 269 ecb_crypt(input, output, key, control_word, count); 270 return; 271 } 272 273 count -= initial; 274 275 if (initial) 276 asm volatile (".byte 0xf3,0x0f,0xa7,0xc8" /* rep xcryptecb */ 277 : "+S"(input), "+D"(output) 278 : "d"(control_word), "b"(key), "c"(initial)); 279 280 asm volatile (".byte 0xf3,0x0f,0xa7,0xc8" /* rep xcryptecb */ 281 : "+S"(input), "+D"(output) 282 : "d"(control_word), "b"(key), "c"(count)); 283 } 284 285 static inline u8 *padlock_xcrypt_cbc(const u8 *input, u8 *output, void *key, 286 u8 *iv, void *control_word, u32 count) 287 { 288 u32 initial = count & (cbc_fetch_blocks - 1); 289 290 if (count < cbc_fetch_blocks) 291 return cbc_crypt(input, output, key, iv, control_word, count); 292 293 count -= initial; 294 295 if (initial) 296 asm volatile (".byte 0xf3,0x0f,0xa7,0xd0" /* rep xcryptcbc */ 297 : "+S" (input), "+D" (output), "+a" (iv) 298 : "d" (control_word), "b" (key), "c" (initial)); 299 300 asm volatile (".byte 0xf3,0x0f,0xa7,0xd0" /* rep xcryptcbc */ 301 : "+S" (input), "+D" (output), "+a" (iv) 302 : "d" (control_word), "b" (key), "c" (count)); 303 return iv; 304 } 305 306 static void padlock_aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) 307 { 308 struct aes_ctx *ctx = aes_ctx(tfm); 309 310 padlock_reset_key(&ctx->cword.encrypt); 311 ecb_crypt(in, out, ctx->E, &ctx->cword.encrypt, 1); 312 padlock_store_cword(&ctx->cword.encrypt); 313 } 314 315 static void padlock_aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) 316 { 317 struct aes_ctx *ctx = aes_ctx(tfm); 318 319 padlock_reset_key(&ctx->cword.encrypt); 320 ecb_crypt(in, out, ctx->D, &ctx->cword.decrypt, 1); 321 padlock_store_cword(&ctx->cword.encrypt); 322 } 323 324 static struct crypto_alg aes_alg = { 325 .cra_name = "aes", 326 .cra_driver_name = "aes-padlock", 327 .cra_priority = PADLOCK_CRA_PRIORITY, 328 .cra_flags = CRYPTO_ALG_TYPE_CIPHER, 329 .cra_blocksize = AES_BLOCK_SIZE, 330 .cra_ctxsize = sizeof(struct aes_ctx), 331 .cra_alignmask = PADLOCK_ALIGNMENT - 1, 332 .cra_module = THIS_MODULE, 333 .cra_u = { 334 .cipher = { 335 .cia_min_keysize = AES_MIN_KEY_SIZE, 336 .cia_max_keysize = AES_MAX_KEY_SIZE, 337 .cia_setkey = aes_set_key, 338 .cia_encrypt = padlock_aes_encrypt, 339 .cia_decrypt = padlock_aes_decrypt, 340 } 341 } 342 }; 343 344 static int ecb_aes_encrypt(struct skcipher_request *req) 345 { 346 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 347 struct aes_ctx *ctx = skcipher_aes_ctx(tfm); 348 struct skcipher_walk walk; 349 unsigned int nbytes; 350 int err; 351 352 padlock_reset_key(&ctx->cword.encrypt); 353 354 err = skcipher_walk_virt(&walk, req, false); 355 356 while ((nbytes = walk.nbytes) != 0) { 357 padlock_xcrypt_ecb(walk.src.virt.addr, walk.dst.virt.addr, 358 ctx->E, &ctx->cword.encrypt, 359 nbytes / AES_BLOCK_SIZE); 360 nbytes &= AES_BLOCK_SIZE - 1; 361 err = skcipher_walk_done(&walk, nbytes); 362 } 363 364 padlock_store_cword(&ctx->cword.encrypt); 365 366 return err; 367 } 368 369 static int ecb_aes_decrypt(struct skcipher_request *req) 370 { 371 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 372 struct aes_ctx *ctx = skcipher_aes_ctx(tfm); 373 struct skcipher_walk walk; 374 unsigned int nbytes; 375 int err; 376 377 padlock_reset_key(&ctx->cword.decrypt); 378 379 err = skcipher_walk_virt(&walk, req, false); 380 381 while ((nbytes = walk.nbytes) != 0) { 382 padlock_xcrypt_ecb(walk.src.virt.addr, walk.dst.virt.addr, 383 ctx->D, &ctx->cword.decrypt, 384 nbytes / AES_BLOCK_SIZE); 385 nbytes &= AES_BLOCK_SIZE - 1; 386 err = skcipher_walk_done(&walk, nbytes); 387 } 388 389 padlock_store_cword(&ctx->cword.encrypt); 390 391 return err; 392 } 393 394 static struct skcipher_alg ecb_aes_alg = { 395 .base.cra_name = "ecb(aes)", 396 .base.cra_driver_name = "ecb-aes-padlock", 397 .base.cra_priority = PADLOCK_COMPOSITE_PRIORITY, 398 .base.cra_blocksize = AES_BLOCK_SIZE, 399 .base.cra_ctxsize = sizeof(struct aes_ctx), 400 .base.cra_alignmask = PADLOCK_ALIGNMENT - 1, 401 .base.cra_module = THIS_MODULE, 402 .min_keysize = AES_MIN_KEY_SIZE, 403 .max_keysize = AES_MAX_KEY_SIZE, 404 .setkey = aes_set_key_skcipher, 405 .encrypt = ecb_aes_encrypt, 406 .decrypt = ecb_aes_decrypt, 407 }; 408 409 static int cbc_aes_encrypt(struct skcipher_request *req) 410 { 411 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 412 struct aes_ctx *ctx = skcipher_aes_ctx(tfm); 413 struct skcipher_walk walk; 414 unsigned int nbytes; 415 int err; 416 417 padlock_reset_key(&ctx->cword.encrypt); 418 419 err = skcipher_walk_virt(&walk, req, false); 420 421 while ((nbytes = walk.nbytes) != 0) { 422 u8 *iv = padlock_xcrypt_cbc(walk.src.virt.addr, 423 walk.dst.virt.addr, ctx->E, 424 walk.iv, &ctx->cword.encrypt, 425 nbytes / AES_BLOCK_SIZE); 426 memcpy(walk.iv, iv, AES_BLOCK_SIZE); 427 nbytes &= AES_BLOCK_SIZE - 1; 428 err = skcipher_walk_done(&walk, nbytes); 429 } 430 431 padlock_store_cword(&ctx->cword.decrypt); 432 433 return err; 434 } 435 436 static int cbc_aes_decrypt(struct skcipher_request *req) 437 { 438 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 439 struct aes_ctx *ctx = skcipher_aes_ctx(tfm); 440 struct skcipher_walk walk; 441 unsigned int nbytes; 442 int err; 443 444 padlock_reset_key(&ctx->cword.encrypt); 445 446 err = skcipher_walk_virt(&walk, req, false); 447 448 while ((nbytes = walk.nbytes) != 0) { 449 padlock_xcrypt_cbc(walk.src.virt.addr, walk.dst.virt.addr, 450 ctx->D, walk.iv, &ctx->cword.decrypt, 451 nbytes / AES_BLOCK_SIZE); 452 nbytes &= AES_BLOCK_SIZE - 1; 453 err = skcipher_walk_done(&walk, nbytes); 454 } 455 456 padlock_store_cword(&ctx->cword.encrypt); 457 458 return err; 459 } 460 461 static struct skcipher_alg cbc_aes_alg = { 462 .base.cra_name = "cbc(aes)", 463 .base.cra_driver_name = "cbc-aes-padlock", 464 .base.cra_priority = PADLOCK_COMPOSITE_PRIORITY, 465 .base.cra_blocksize = AES_BLOCK_SIZE, 466 .base.cra_ctxsize = sizeof(struct aes_ctx), 467 .base.cra_alignmask = PADLOCK_ALIGNMENT - 1, 468 .base.cra_module = THIS_MODULE, 469 .min_keysize = AES_MIN_KEY_SIZE, 470 .max_keysize = AES_MAX_KEY_SIZE, 471 .ivsize = AES_BLOCK_SIZE, 472 .setkey = aes_set_key_skcipher, 473 .encrypt = cbc_aes_encrypt, 474 .decrypt = cbc_aes_decrypt, 475 }; 476 477 static const struct x86_cpu_id padlock_cpu_id[] = { 478 X86_MATCH_FEATURE(X86_FEATURE_XCRYPT, NULL), 479 {} 480 }; 481 MODULE_DEVICE_TABLE(x86cpu, padlock_cpu_id); 482 483 static int __init padlock_init(void) 484 { 485 int ret; 486 struct cpuinfo_x86 *c = &cpu_data(0); 487 488 if (!x86_match_cpu(padlock_cpu_id)) 489 return -ENODEV; 490 491 if (!boot_cpu_has(X86_FEATURE_XCRYPT_EN)) { 492 printk(KERN_NOTICE PFX "VIA PadLock detected, but not enabled. Hmm, strange...\n"); 493 return -ENODEV; 494 } 495 496 if ((ret = crypto_register_alg(&aes_alg)) != 0) 497 goto aes_err; 498 499 if ((ret = crypto_register_skcipher(&ecb_aes_alg)) != 0) 500 goto ecb_aes_err; 501 502 if ((ret = crypto_register_skcipher(&cbc_aes_alg)) != 0) 503 goto cbc_aes_err; 504 505 printk(KERN_NOTICE PFX "Using VIA PadLock ACE for AES algorithm.\n"); 506 507 if (c->x86 == 6 && c->x86_model == 15 && c->x86_stepping == 2) { 508 ecb_fetch_blocks = MAX_ECB_FETCH_BLOCKS; 509 cbc_fetch_blocks = MAX_CBC_FETCH_BLOCKS; 510 printk(KERN_NOTICE PFX "VIA Nano stepping 2 detected: enabling workaround.\n"); 511 } 512 513 out: 514 return ret; 515 516 cbc_aes_err: 517 crypto_unregister_skcipher(&ecb_aes_alg); 518 ecb_aes_err: 519 crypto_unregister_alg(&aes_alg); 520 aes_err: 521 printk(KERN_ERR PFX "VIA PadLock AES initialization failed.\n"); 522 goto out; 523 } 524 525 static void __exit padlock_fini(void) 526 { 527 crypto_unregister_skcipher(&cbc_aes_alg); 528 crypto_unregister_skcipher(&ecb_aes_alg); 529 crypto_unregister_alg(&aes_alg); 530 } 531 532 module_init(padlock_init); 533 module_exit(padlock_fini); 534 535 MODULE_DESCRIPTION("VIA PadLock AES algorithm support"); 536 MODULE_LICENSE("GPL"); 537 MODULE_AUTHOR("Michal Ludvig"); 538 539 MODULE_ALIAS_CRYPTO("aes"); 540