arch/arm64/crypto/ghash-ce-glue.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Accelerated GHASH implementation with ARMv8 PMULL instructions.
   4  *
   5  * Copyright (C) 2014 - 2018 Linaro Ltd. <ard.biesheuvel@linaro.org>
   6  */
   7
   8 #include <asm/neon.h>
   9 #include <asm/simd.h>
  10 #include <asm/unaligned.h>
  11 #include <crypto/aes.h>
  12 #include <crypto/algapi.h>
  13 #include <crypto/b128ops.h>
  14 #include <crypto/gf128mul.h>
  15 #include <crypto/internal/aead.h>
  16 #include <crypto/internal/hash.h>
  17 #include <crypto/internal/simd.h>
  18 #include <crypto/internal/skcipher.h>
  19 #include <crypto/scatterwalk.h>
  20 #include <linux/cpufeature.h>
  21 #include <linux/crypto.h>
  22 #include <linux/module.h>
  23
  24 MODULE_DESCRIPTION("GHASH and AES-GCM using ARMv8 Crypto Extensions");
  25 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
  26 MODULE_LICENSE("GPL v2");
  27 MODULE_ALIAS_CRYPTO("ghash");
  28
  29 #define GHASH_BLOCK_SIZE        16
  30 #define GHASH_DIGEST_SIZE       16
  31 #define GCM_IV_SIZE             12
  32
  33 struct ghash_key {
  34         be128                   k;
  35         u64                     h[][2];
  36 };
  37
  38 struct ghash_desc_ctx {
  39         u64 digest[GHASH_DIGEST_SIZE/sizeof(u64)];
  40         u8 buf[GHASH_BLOCK_SIZE];
  41         u32 count;
  42 };
  43
  44 struct gcm_aes_ctx {
  45         struct crypto_aes_ctx   aes_key;
  46         struct ghash_key        ghash_key;
  47 };
  48
  49 asmlinkage void pmull_ghash_update_p64(int blocks, u64 dg[], const char *src,
  50                                        u64 const h[][2], const char *head);
  51
  52 asmlinkage void pmull_ghash_update_p8(int blocks, u64 dg[], const char *src,
  53                                       u64 const h[][2], const char *head);
  54
  55 asmlinkage void pmull_gcm_encrypt(int bytes, u8 dst[], const u8 src[],
  56                                   u64 const h[][2], u64 dg[], u8 ctr[],
  57                                   u32 const rk[], int rounds, u8 tag[]);
  58 asmlinkage int pmull_gcm_decrypt(int bytes, u8 dst[], const u8 src[],
  59                                  u64 const h[][2], u64 dg[], u8 ctr[],
  60                                  u32 const rk[], int rounds, const u8 l[],
  61                                  const u8 tag[], u64 authsize);
  62
  63 static int ghash_init(struct shash_desc *desc)
  64 {
  65         struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
  66
  67         *ctx = (struct ghash_desc_ctx){};
  68         return 0;
  69 }
  70
  71 static void ghash_do_update(int blocks, u64 dg[], const char *src,
  72                             struct ghash_key *key, const char *head)
  73 {
  74         be128 dst = { cpu_to_be64(dg[1]), cpu_to_be64(dg[0]) };
  75
  76         do {
  77                 const u8 *in = src;
  78
  79                 if (head) {
  80                         in = head;
  81                         blocks++;
  82                         head = NULL;
  83                 } else {
  84                         src += GHASH_BLOCK_SIZE;
  85                 }
  86
  87                 crypto_xor((u8 *)&dst, in, GHASH_BLOCK_SIZE);
  88                 gf128mul_lle(&dst, &key->k);
  89         } while (--blocks);
  90
  91         dg[0] = be64_to_cpu(dst.b);
  92         dg[1] = be64_to_cpu(dst.a);
  93 }
  94
  95 static __always_inline
  96 void ghash_do_simd_update(int blocks, u64 dg[], const char *src,
  97                           struct ghash_key *key, const char *head,
  98                           void (*simd_update)(int blocks, u64 dg[],
  99                                               const char *src,
 100                                               u64 const h[][2],
 101                                               const char *head))
 102 {
 103         if (likely(crypto_simd_usable())) {
 104                 kernel_neon_begin();
 105                 simd_update(blocks, dg, src, key->h, head);
 106                 kernel_neon_end();
 107         } else {
 108                 ghash_do_update(blocks, dg, src, key, head);
 109         }
 110 }
 111
 112 /* avoid hogging the CPU for too long */
 113 #define MAX_BLOCKS      (SZ_64K / GHASH_BLOCK_SIZE)
 114
 115 static int ghash_update(struct shash_desc *desc, const u8 *src,
 116                         unsigned int len)
 117 {
 118         struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
 119         unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
 120
 121         ctx->count += len;
 122
 123         if ((partial + len) >= GHASH_BLOCK_SIZE) {
 124                 struct ghash_key *key = crypto_shash_ctx(desc->tfm);
 125                 int blocks;
 126
 127                 if (partial) {
 128                         int p = GHASH_BLOCK_SIZE - partial;
 129
 130                         memcpy(ctx->buf + partial, src, p);
 131                         src += p;
 132                         len -= p;
 133                 }
 134
 135                 blocks = len / GHASH_BLOCK_SIZE;
 136                 len %= GHASH_BLOCK_SIZE;
 137
 138                 do {
 139                         int chunk = min(blocks, MAX_BLOCKS);
 140
 141                         ghash_do_simd_update(chunk, ctx->digest, src, key,
 142                                              partial ? ctx->buf : NULL,
 143                                              pmull_ghash_update_p8);
 144
 145                         blocks -= chunk;
 146                         src += chunk * GHASH_BLOCK_SIZE;
 147                         partial = 0;
 148                 } while (unlikely(blocks > 0));
 149         }
 150         if (len)
 151                 memcpy(ctx->buf + partial, src, len);
 152         return 0;
 153 }
 154
 155 static int ghash_final(struct shash_desc *desc, u8 *dst)
 156 {
 157         struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
 158         unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
 159
 160         if (partial) {
 161                 struct ghash_key *key = crypto_shash_ctx(desc->tfm);
 162
 163                 memset(ctx->buf + partial, 0, GHASH_BLOCK_SIZE - partial);
 164
 165                 ghash_do_simd_update(1, ctx->digest, ctx->buf, key, NULL,
 166                                      pmull_ghash_update_p8);
 167         }
 168         put_unaligned_be64(ctx->digest[1], dst);
 169         put_unaligned_be64(ctx->digest[0], dst + 8);
 170
 171         memzero_explicit(ctx, sizeof(*ctx));
 172         return 0;
 173 }
 174
 175 static void ghash_reflect(u64 h[], const be128 *k)
 176 {
 177         u64 carry = be64_to_cpu(k->a) & BIT(63) ? 1 : 0;
 178
 179         h[0] = (be64_to_cpu(k->b) << 1) | carry;
 180         h[1] = (be64_to_cpu(k->a) << 1) | (be64_to_cpu(k->b) >> 63);
 181
 182         if (carry)
 183                 h[1] ^= 0xc200000000000000UL;
 184 }
 185
 186 static int ghash_setkey(struct crypto_shash *tfm,
 187                         const u8 *inkey, unsigned int keylen)
 188 {
 189         struct ghash_key *key = crypto_shash_ctx(tfm);
 190
 191         if (keylen != GHASH_BLOCK_SIZE)
 192                 return -EINVAL;
 193
 194         /* needed for the fallback */
 195         memcpy(&key->k, inkey, GHASH_BLOCK_SIZE);
 196
 197         ghash_reflect(key->h[0], &key->k);
 198         return 0;
 199 }
 200
 201 static struct shash_alg ghash_alg = {
 202         .base.cra_name          = "ghash",
 203         .base.cra_driver_name   = "ghash-neon",
 204         .base.cra_priority      = 150,
 205         .base.cra_blocksize     = GHASH_BLOCK_SIZE,
 206         .base.cra_ctxsize       = sizeof(struct ghash_key) + sizeof(u64[2]),
 207         .base.cra_module        = THIS_MODULE,
 208
 209         .digestsize             = GHASH_DIGEST_SIZE,
 210         .init                   = ghash_init,
 211         .update                 = ghash_update,
 212         .final                  = ghash_final,
 213         .setkey                 = ghash_setkey,
 214         .descsize               = sizeof(struct ghash_desc_ctx),
 215 };
 216
 217 static int num_rounds(struct crypto_aes_ctx *ctx)
 218 {
 219         /*
 220          * # of rounds specified by AES:
 221          * 128 bit key          10 rounds
 222          * 192 bit key          12 rounds
 223          * 256 bit key          14 rounds
 224          * => n byte key        => 6 + (n/4) rounds
 225          */
 226         return 6 + ctx->key_length / 4;
 227 }
 228
 229 static int gcm_setkey(struct crypto_aead *tfm, const u8 *inkey,
 230                       unsigned int keylen)
 231 {
 232         struct gcm_aes_ctx *ctx = crypto_aead_ctx(tfm);
 233         u8 key[GHASH_BLOCK_SIZE];
 234         be128 h;
 235         int ret;
 236
 237         ret = aes_expandkey(&ctx->aes_key, inkey, keylen);
 238         if (ret)
 239                 return -EINVAL;
 240
 241         aes_encrypt(&ctx->aes_key, key, (u8[AES_BLOCK_SIZE]){});
 242
 243         /* needed for the fallback */
 244         memcpy(&ctx->ghash_key.k, key, GHASH_BLOCK_SIZE);
 245
 246         ghash_reflect(ctx->ghash_key.h[0], &ctx->ghash_key.k);
 247
 248         h = ctx->ghash_key.k;
 249         gf128mul_lle(&h, &ctx->ghash_key.k);
 250         ghash_reflect(ctx->ghash_key.h[1], &h);
 251
 252         gf128mul_lle(&h, &ctx->ghash_key.k);
 253         ghash_reflect(ctx->ghash_key.h[2], &h);
 254
 255         gf128mul_lle(&h, &ctx->ghash_key.k);
 256         ghash_reflect(ctx->ghash_key.h[3], &h);
 257
 258         return 0;
 259 }
 260
 261 static int gcm_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
 262 {
 263         switch (authsize) {
 264         case 4:
 265         case 8:
 266         case 12 ... 16:
 267                 break;
 268         default:
 269                 return -EINVAL;
 270         }
 271         return 0;
 272 }
 273
 274 static void gcm_update_mac(u64 dg[], const u8 *src, int count, u8 buf[],
 275                            int *buf_count, struct gcm_aes_ctx *ctx)
 276 {
 277         if (*buf_count > 0) {
 278                 int buf_added = min(count, GHASH_BLOCK_SIZE - *buf_count);
 279
 280                 memcpy(&buf[*buf_count], src, buf_added);
 281
 282                 *buf_count += buf_added;
 283                 src += buf_added;
 284                 count -= buf_added;
 285         }
 286
 287         if (count >= GHASH_BLOCK_SIZE || *buf_count == GHASH_BLOCK_SIZE) {
 288                 int blocks = count / GHASH_BLOCK_SIZE;
 289
 290                 ghash_do_simd_update(blocks, dg, src, &ctx->ghash_key,
 291                                      *buf_count ? buf : NULL,
 292                                      pmull_ghash_update_p64);
 293
 294                 src += blocks * GHASH_BLOCK_SIZE;
 295                 count %= GHASH_BLOCK_SIZE;
 296                 *buf_count = 0;
 297         }
 298
 299         if (count > 0) {
 300                 memcpy(buf, src, count);
 301                 *buf_count = count;
 302         }
 303 }
 304
 305 static void gcm_calculate_auth_mac(struct aead_request *req, u64 dg[])
 306 {
 307         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 308         struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
 309         u8 buf[GHASH_BLOCK_SIZE];
 310         struct scatter_walk walk;
 311         u32 len = req->assoclen;
 312         int buf_count = 0;
 313
 314         scatterwalk_start(&walk, req->src);
 315
 316         do {
 317                 u32 n = scatterwalk_clamp(&walk, len);
 318                 u8 *p;
 319
 320                 if (!n) {
 321                         scatterwalk_start(&walk, sg_next(walk.sg));
 322                         n = scatterwalk_clamp(&walk, len);
 323                 }
 324                 p = scatterwalk_map(&walk);
 325
 326                 gcm_update_mac(dg, p, n, buf, &buf_count, ctx);
 327                 len -= n;
 328
 329                 scatterwalk_unmap(p);
 330                 scatterwalk_advance(&walk, n);
 331                 scatterwalk_done(&walk, 0, len);
 332         } while (len);
 333
 334         if (buf_count) {
 335                 memset(&buf[buf_count], 0, GHASH_BLOCK_SIZE - buf_count);
 336                 ghash_do_simd_update(1, dg, buf, &ctx->ghash_key, NULL,
 337                                      pmull_ghash_update_p64);
 338         }
 339 }
 340
 341 static int gcm_encrypt(struct aead_request *req)
 342 {
 343         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 344         struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
 345         int nrounds = num_rounds(&ctx->aes_key);
 346         struct skcipher_walk walk;
 347         u8 buf[AES_BLOCK_SIZE];
 348         u8 iv[AES_BLOCK_SIZE];
 349         u64 dg[2] = {};
 350         be128 lengths;
 351         u8 *tag;
 352         int err;
 353
 354         lengths.a = cpu_to_be64(req->assoclen * 8);
 355         lengths.b = cpu_to_be64(req->cryptlen * 8);
 356
 357         if (req->assoclen)
 358                 gcm_calculate_auth_mac(req, dg);
 359
 360         memcpy(iv, req->iv, GCM_IV_SIZE);
 361         put_unaligned_be32(2, iv + GCM_IV_SIZE);
 362
 363         err = skcipher_walk_aead_encrypt(&walk, req, false);
 364
 365         if (likely(crypto_simd_usable())) {
 366                 do {
 367                         const u8 *src = walk.src.virt.addr;
 368                         u8 *dst = walk.dst.virt.addr;
 369                         int nbytes = walk.nbytes;
 370
 371                         tag = (u8 *)&lengths;
 372
 373                         if (unlikely(nbytes > 0 && nbytes < AES_BLOCK_SIZE)) {
 374                                 src = dst = memcpy(buf + sizeof(buf) - nbytes,
 375                                                    src, nbytes);
 376                         } else if (nbytes < walk.total) {
 377                                 nbytes &= ~(AES_BLOCK_SIZE - 1);
 378                                 tag = NULL;
 379                         }
 380
 381                         kernel_neon_begin();
 382                         pmull_gcm_encrypt(nbytes, dst, src, ctx->ghash_key.h,
 383                                           dg, iv, ctx->aes_key.key_enc, nrounds,
 384                                           tag);
 385                         kernel_neon_end();
 386
 387                         if (unlikely(!nbytes))
 388                                 break;
 389
 390                         if (unlikely(nbytes > 0 && nbytes < AES_BLOCK_SIZE))
 391                                 memcpy(walk.dst.virt.addr,
 392                                        buf + sizeof(buf) - nbytes, nbytes);
 393
 394                         err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
 395                 } while (walk.nbytes);
 396         } else {
 397                 while (walk.nbytes >= AES_BLOCK_SIZE) {
 398                         int blocks = walk.nbytes / AES_BLOCK_SIZE;
 399                         const u8 *src = walk.src.virt.addr;
 400                         u8 *dst = walk.dst.virt.addr;
 401                         int remaining = blocks;
 402
 403                         do {
 404                                 aes_encrypt(&ctx->aes_key, buf, iv);
 405                                 crypto_xor_cpy(dst, src, buf, AES_BLOCK_SIZE);
 406                                 crypto_inc(iv, AES_BLOCK_SIZE);
 407
 408                                 dst += AES_BLOCK_SIZE;
 409                                 src += AES_BLOCK_SIZE;
 410                         } while (--remaining > 0);
 411
 412                         ghash_do_update(blocks, dg, walk.dst.virt.addr,
 413                                         &ctx->ghash_key, NULL);
 414
 415                         err = skcipher_walk_done(&walk,
 416                                                  walk.nbytes % AES_BLOCK_SIZE);
 417                 }
 418
 419                 /* handle the tail */
 420                 if (walk.nbytes) {
 421                         aes_encrypt(&ctx->aes_key, buf, iv);
 422
 423                         crypto_xor_cpy(walk.dst.virt.addr, walk.src.virt.addr,
 424                                        buf, walk.nbytes);
 425
 426                         memcpy(buf, walk.dst.virt.addr, walk.nbytes);
 427                         memset(buf + walk.nbytes, 0, sizeof(buf) - walk.nbytes);
 428                 }
 429
 430                 tag = (u8 *)&lengths;
 431                 ghash_do_update(1, dg, tag, &ctx->ghash_key,
 432                                 walk.nbytes ? buf : NULL);
 433
 434                 if (walk.nbytes)
 435                         err = skcipher_walk_done(&walk, 0);
 436
 437                 put_unaligned_be64(dg[1], tag);
 438                 put_unaligned_be64(dg[0], tag + 8);
 439                 put_unaligned_be32(1, iv + GCM_IV_SIZE);
 440                 aes_encrypt(&ctx->aes_key, iv, iv);
 441                 crypto_xor(tag, iv, AES_BLOCK_SIZE);
 442         }
 443
 444         if (err)
 445                 return err;
 446
 447         /* copy authtag to end of dst */
 448         scatterwalk_map_and_copy(tag, req->dst, req->assoclen + req->cryptlen,
 449                                  crypto_aead_authsize(aead), 1);
 450
 451         return 0;
 452 }
 453
 454 static int gcm_decrypt(struct aead_request *req)
 455 {
 456         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 457         struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
 458         unsigned int authsize = crypto_aead_authsize(aead);
 459         int nrounds = num_rounds(&ctx->aes_key);
 460         struct skcipher_walk walk;
 461         u8 otag[AES_BLOCK_SIZE];
 462         u8 buf[AES_BLOCK_SIZE];
 463         u8 iv[AES_BLOCK_SIZE];
 464         u64 dg[2] = {};
 465         be128 lengths;
 466         u8 *tag;
 467         int err;
 468
 469         lengths.a = cpu_to_be64(req->assoclen * 8);
 470         lengths.b = cpu_to_be64((req->cryptlen - authsize) * 8);
 471
 472         if (req->assoclen)
 473                 gcm_calculate_auth_mac(req, dg);
 474
 475         memcpy(iv, req->iv, GCM_IV_SIZE);
 476         put_unaligned_be32(2, iv + GCM_IV_SIZE);
 477
 478         scatterwalk_map_and_copy(otag, req->src,
 479                                  req->assoclen + req->cryptlen - authsize,
 480                                  authsize, 0);
 481
 482         err = skcipher_walk_aead_decrypt(&walk, req, false);
 483
 484         if (likely(crypto_simd_usable())) {
 485                 int ret;
 486
 487                 do {
 488                         const u8 *src = walk.src.virt.addr;
 489                         u8 *dst = walk.dst.virt.addr;
 490                         int nbytes = walk.nbytes;
 491
 492                         tag = (u8 *)&lengths;
 493
 494                         if (unlikely(nbytes > 0 && nbytes < AES_BLOCK_SIZE)) {
 495                                 src = dst = memcpy(buf + sizeof(buf) - nbytes,
 496                                                    src, nbytes);
 497                         } else if (nbytes < walk.total) {
 498                                 nbytes &= ~(AES_BLOCK_SIZE - 1);
 499                                 tag = NULL;
 500                         }
 501
 502                         kernel_neon_begin();
 503                         ret = pmull_gcm_decrypt(nbytes, dst, src,
 504                                                 ctx->ghash_key.h,
 505                                                 dg, iv, ctx->aes_key.key_enc,
 506                                                 nrounds, tag, otag, authsize);
 507                         kernel_neon_end();
 508
 509                         if (unlikely(!nbytes))
 510                                 break;
 511
 512                         if (unlikely(nbytes > 0 && nbytes < AES_BLOCK_SIZE))
 513                                 memcpy(walk.dst.virt.addr,
 514                                        buf + sizeof(buf) - nbytes, nbytes);
 515
 516                         err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
 517                 } while (walk.nbytes);
 518
 519                 if (err)
 520                         return err;
 521                 if (ret)
 522                         return -EBADMSG;
 523         } else {
 524                 while (walk.nbytes >= AES_BLOCK_SIZE) {
 525                         int blocks = walk.nbytes / AES_BLOCK_SIZE;
 526                         const u8 *src = walk.src.virt.addr;
 527                         u8 *dst = walk.dst.virt.addr;
 528
 529                         ghash_do_update(blocks, dg, walk.src.virt.addr,
 530                                         &ctx->ghash_key, NULL);
 531
 532                         do {
 533                                 aes_encrypt(&ctx->aes_key, buf, iv);
 534                                 crypto_xor_cpy(dst, src, buf, AES_BLOCK_SIZE);
 535                                 crypto_inc(iv, AES_BLOCK_SIZE);
 536
 537                                 dst += AES_BLOCK_SIZE;
 538                                 src += AES_BLOCK_SIZE;
 539                         } while (--blocks > 0);
 540
 541                         err = skcipher_walk_done(&walk,
 542                                                  walk.nbytes % AES_BLOCK_SIZE);
 543                 }
 544
 545                 /* handle the tail */
 546                 if (walk.nbytes) {
 547                         memcpy(buf, walk.src.virt.addr, walk.nbytes);
 548                         memset(buf + walk.nbytes, 0, sizeof(buf) - walk.nbytes);
 549                 }
 550
 551                 tag = (u8 *)&lengths;
 552                 ghash_do_update(1, dg, tag, &ctx->ghash_key,
 553                                 walk.nbytes ? buf : NULL);
 554
 555                 if (walk.nbytes) {
 556                         aes_encrypt(&ctx->aes_key, buf, iv);
 557
 558                         crypto_xor_cpy(walk.dst.virt.addr, walk.src.virt.addr,
 559                                        buf, walk.nbytes);
 560
 561                         err = skcipher_walk_done(&walk, 0);
 562                 }
 563
 564                 if (err)
 565                         return err;
 566
 567                 put_unaligned_be64(dg[1], tag);
 568                 put_unaligned_be64(dg[0], tag + 8);
 569                 put_unaligned_be32(1, iv + GCM_IV_SIZE);
 570                 aes_encrypt(&ctx->aes_key, iv, iv);
 571                 crypto_xor(tag, iv, AES_BLOCK_SIZE);
 572
 573                 if (crypto_memneq(tag, otag, authsize)) {
 574                         memzero_explicit(tag, AES_BLOCK_SIZE);
 575                         return -EBADMSG;
 576                 }
 577         }
 578         return 0;
 579 }
 580
 581 static struct aead_alg gcm_aes_alg = {
 582         .ivsize                 = GCM_IV_SIZE,
 583         .chunksize              = AES_BLOCK_SIZE,
 584         .maxauthsize            = AES_BLOCK_SIZE,
 585         .setkey                 = gcm_setkey,
 586         .setauthsize            = gcm_setauthsize,
 587         .encrypt                = gcm_encrypt,
 588         .decrypt                = gcm_decrypt,
 589
 590         .base.cra_name          = "gcm(aes)",
 591         .base.cra_driver_name   = "gcm-aes-ce",
 592         .base.cra_priority      = 300,
 593         .base.cra_blocksize     = 1,
 594         .base.cra_ctxsize       = sizeof(struct gcm_aes_ctx) +
 595                                   4 * sizeof(u64[2]),
 596         .base.cra_module        = THIS_MODULE,
 597 };
 598
 599 static int __init ghash_ce_mod_init(void)
 600 {
 601         if (!cpu_have_named_feature(ASIMD))
 602                 return -ENODEV;
 603
 604         if (cpu_have_named_feature(PMULL))
 605                 return crypto_register_aead(&gcm_aes_alg);
 606
 607         return crypto_register_shash(&ghash_alg);
 608 }
 609
 610 static void __exit ghash_ce_mod_exit(void)
 611 {
 612         if (cpu_have_named_feature(PMULL))
 613                 crypto_unregister_aead(&gcm_aes_alg);
 614         else
 615                 crypto_unregister_shash(&ghash_alg);
 616 }
 617
 618 static const struct cpu_feature ghash_cpu_feature[] = {
 619         { cpu_feature(PMULL) }, { }
 620 };
 621 MODULE_DEVICE_TABLE(cpu, ghash_cpu_feature);
 622
 623 module_init(ghash_ce_mod_init);
 624 module_exit(ghash_ce_mod_exit);