block/t10-pi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * t10_pi.c - Functions for generating and verifying T10 Protection
   4  *            Information.
   5  */
   6
   7 #include <linux/t10-pi.h>
   8 #include <linux/blk-integrity.h>
   9 #include <linux/crc-t10dif.h>
  10 #include <linux/crc64.h>
  11 #include <linux/module.h>
  12 #include <net/checksum.h>
  13 #include <asm/unaligned.h>
  14 #include "blk.h"
  15
  16 struct blk_integrity_iter {
  17         void                    *prot_buf;
  18         void                    *data_buf;
  19         sector_t                seed;
  20         unsigned int            data_size;
  21         unsigned short          interval;
  22         const char              *disk_name;
  23 };
  24
  25 static __be16 t10_pi_csum(__be16 csum, void *data, unsigned int len,
  26                 unsigned char csum_type)
  27 {
  28         if (csum_type == BLK_INTEGRITY_CSUM_IP)
  29                 return (__force __be16)ip_compute_csum(data, len);
  30         return cpu_to_be16(crc_t10dif_update(be16_to_cpu(csum), data, len));
  31 }
  32
  33 /*
  34  * Type 1 and Type 2 protection use the same format: 16 bit guard tag,
  35  * 16 bit app tag, 32 bit reference tag. Type 3 does not define the ref
  36  * tag.
  37  */
  38 static void t10_pi_generate(struct blk_integrity_iter *iter,
  39                 struct blk_integrity *bi)
  40 {
  41         u8 offset = bi->pi_offset;
  42         unsigned int i;
  43
  44         for (i = 0 ; i < iter->data_size ; i += iter->interval) {
  45                 struct t10_pi_tuple *pi = iter->prot_buf + offset;
  46
  47                 pi->guard_tag = t10_pi_csum(0, iter->data_buf, iter->interval,
  48                                 bi->csum_type);
  49                 if (offset)
  50                         pi->guard_tag = t10_pi_csum(pi->guard_tag,
  51                                         iter->prot_buf, offset, bi->csum_type);
  52                 pi->app_tag = 0;
  53
  54                 if (bi->flags & BLK_INTEGRITY_REF_TAG)
  55                         pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed));
  56                 else
  57                         pi->ref_tag = 0;
  58
  59                 iter->data_buf += iter->interval;
  60                 iter->prot_buf += bi->tuple_size;
  61                 iter->seed++;
  62         }
  63 }
  64
  65 static blk_status_t t10_pi_verify(struct blk_integrity_iter *iter,
  66                 struct blk_integrity *bi)
  67 {
  68         u8 offset = bi->pi_offset;
  69         unsigned int i;
  70
  71         for (i = 0 ; i < iter->data_size ; i += iter->interval) {
  72                 struct t10_pi_tuple *pi = iter->prot_buf + offset;
  73                 __be16 csum;
  74
  75                 if (bi->flags & BLK_INTEGRITY_REF_TAG) {
  76                         if (pi->app_tag == T10_PI_APP_ESCAPE)
  77                                 goto next;
  78
  79                         if (be32_to_cpu(pi->ref_tag) !=
  80                             lower_32_bits(iter->seed)) {
  81                                 pr_err("%s: ref tag error at location %llu " \
  82                                        "(rcvd %u)\n", iter->disk_name,
  83                                        (unsigned long long)
  84                                        iter->seed, be32_to_cpu(pi->ref_tag));
  85                                 return BLK_STS_PROTECTION;
  86                         }
  87                 } else {
  88                         if (pi->app_tag == T10_PI_APP_ESCAPE &&
  89                             pi->ref_tag == T10_PI_REF_ESCAPE)
  90                                 goto next;
  91                 }
  92
  93                 csum = t10_pi_csum(0, iter->data_buf, iter->interval,
  94                                 bi->csum_type);
  95                 if (offset)
  96                         csum = t10_pi_csum(csum, iter->prot_buf, offset,
  97                                         bi->csum_type);
  98
  99                 if (pi->guard_tag != csum) {
 100                         pr_err("%s: guard tag error at sector %llu " \
 101                                "(rcvd %04x, want %04x)\n", iter->disk_name,
 102                                (unsigned long long)iter->seed,
 103                                be16_to_cpu(pi->guard_tag), be16_to_cpu(csum));
 104                         return BLK_STS_PROTECTION;
 105                 }
 106
 107 next:
 108                 iter->data_buf += iter->interval;
 109                 iter->prot_buf += bi->tuple_size;
 110                 iter->seed++;
 111         }
 112
 113         return BLK_STS_OK;
 114 }
 115
 116 /**
 117  * t10_pi_type1_prepare - prepare PI prior submitting request to device
 118  * @rq:              request with PI that should be prepared
 119  *
 120  * For Type 1/Type 2, the virtual start sector is the one that was
 121  * originally submitted by the block layer for the ref_tag usage. Due to
 122  * partitioning, MD/DM cloning, etc. the actual physical start sector is
 123  * likely to be different. Remap protection information to match the
 124  * physical LBA.
 125  */
 126 static void t10_pi_type1_prepare(struct request *rq)
 127 {
 128         struct blk_integrity *bi = &rq->q->limits.integrity;
 129         const int tuple_sz = bi->tuple_size;
 130         u32 ref_tag = t10_pi_ref_tag(rq);
 131         u8 offset = bi->pi_offset;
 132         struct bio *bio;
 133
 134         __rq_for_each_bio(bio, rq) {
 135                 struct bio_integrity_payload *bip = bio_integrity(bio);
 136                 u32 virt = bip_get_seed(bip) & 0xffffffff;
 137                 struct bio_vec iv;
 138                 struct bvec_iter iter;
 139
 140                 /* Already remapped? */
 141                 if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
 142                         break;
 143
 144                 bip_for_each_vec(iv, bip, iter) {
 145                         unsigned int j;
 146                         void *p;
 147
 148                         p = bvec_kmap_local(&iv);
 149                         for (j = 0; j < iv.bv_len; j += tuple_sz) {
 150                                 struct t10_pi_tuple *pi = p + offset;
 151
 152                                 if (be32_to_cpu(pi->ref_tag) == virt)
 153                                         pi->ref_tag = cpu_to_be32(ref_tag);
 154                                 virt++;
 155                                 ref_tag++;
 156                                 p += tuple_sz;
 157                         }
 158                         kunmap_local(p);
 159                 }
 160
 161                 bip->bip_flags |= BIP_MAPPED_INTEGRITY;
 162         }
 163 }
 164
 165 /**
 166  * t10_pi_type1_complete - prepare PI prior returning request to the blk layer
 167  * @rq:              request with PI that should be prepared
 168  * @nr_bytes:        total bytes to prepare
 169  *
 170  * For Type 1/Type 2, the virtual start sector is the one that was
 171  * originally submitted by the block layer for the ref_tag usage. Due to
 172  * partitioning, MD/DM cloning, etc. the actual physical start sector is
 173  * likely to be different. Since the physical start sector was submitted
 174  * to the device, we should remap it back to virtual values expected by the
 175  * block layer.
 176  */
 177 static void t10_pi_type1_complete(struct request *rq, unsigned int nr_bytes)
 178 {
 179         struct blk_integrity *bi = &rq->q->limits.integrity;
 180         unsigned intervals = nr_bytes >> bi->interval_exp;
 181         const int tuple_sz = bi->tuple_size;
 182         u32 ref_tag = t10_pi_ref_tag(rq);
 183         u8 offset = bi->pi_offset;
 184         struct bio *bio;
 185
 186         __rq_for_each_bio(bio, rq) {
 187                 struct bio_integrity_payload *bip = bio_integrity(bio);
 188                 u32 virt = bip_get_seed(bip) & 0xffffffff;
 189                 struct bio_vec iv;
 190                 struct bvec_iter iter;
 191
 192                 bip_for_each_vec(iv, bip, iter) {
 193                         unsigned int j;
 194                         void *p;
 195
 196                         p = bvec_kmap_local(&iv);
 197                         for (j = 0; j < iv.bv_len && intervals; j += tuple_sz) {
 198                                 struct t10_pi_tuple *pi = p + offset;
 199
 200                                 if (be32_to_cpu(pi->ref_tag) == ref_tag)
 201                                         pi->ref_tag = cpu_to_be32(virt);
 202                                 virt++;
 203                                 ref_tag++;
 204                                 intervals--;
 205                                 p += tuple_sz;
 206                         }
 207                         kunmap_local(p);
 208                 }
 209         }
 210 }
 211
 212 static __be64 ext_pi_crc64(u64 crc, void *data, unsigned int len)
 213 {
 214         return cpu_to_be64(crc64_rocksoft_update(crc, data, len));
 215 }
 216
 217 static void ext_pi_crc64_generate(struct blk_integrity_iter *iter,
 218                 struct blk_integrity *bi)
 219 {
 220         u8 offset = bi->pi_offset;
 221         unsigned int i;
 222
 223         for (i = 0 ; i < iter->data_size ; i += iter->interval) {
 224                 struct crc64_pi_tuple *pi = iter->prot_buf + offset;
 225
 226                 pi->guard_tag = ext_pi_crc64(0, iter->data_buf, iter->interval);
 227                 if (offset)
 228                         pi->guard_tag = ext_pi_crc64(be64_to_cpu(pi->guard_tag),
 229                                         iter->prot_buf, offset);
 230                 pi->app_tag = 0;
 231
 232                 if (bi->flags & BLK_INTEGRITY_REF_TAG)
 233                         put_unaligned_be48(iter->seed, pi->ref_tag);
 234                 else
 235                         put_unaligned_be48(0ULL, pi->ref_tag);
 236
 237                 iter->data_buf += iter->interval;
 238                 iter->prot_buf += bi->tuple_size;
 239                 iter->seed++;
 240         }
 241 }
 242
 243 static bool ext_pi_ref_escape(u8 *ref_tag)
 244 {
 245         static u8 ref_escape[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 246
 247         return memcmp(ref_tag, ref_escape, sizeof(ref_escape)) == 0;
 248 }
 249
 250 static blk_status_t ext_pi_crc64_verify(struct blk_integrity_iter *iter,
 251                 struct blk_integrity *bi)
 252 {
 253         u8 offset = bi->pi_offset;
 254         unsigned int i;
 255
 256         for (i = 0; i < iter->data_size; i += iter->interval) {
 257                 struct crc64_pi_tuple *pi = iter->prot_buf + offset;
 258                 u64 ref, seed;
 259                 __be64 csum;
 260
 261                 if (bi->flags & BLK_INTEGRITY_REF_TAG) {
 262                         if (pi->app_tag == T10_PI_APP_ESCAPE)
 263                                 goto next;
 264
 265                         ref = get_unaligned_be48(pi->ref_tag);
 266                         seed = lower_48_bits(iter->seed);
 267                         if (ref != seed) {
 268                                 pr_err("%s: ref tag error at location %llu (rcvd %llu)\n",
 269                                         iter->disk_name, seed, ref);
 270                                 return BLK_STS_PROTECTION;
 271                         }
 272                 } else {
 273                         if (pi->app_tag == T10_PI_APP_ESCAPE &&
 274                             ext_pi_ref_escape(pi->ref_tag))
 275                                 goto next;
 276                 }
 277
 278                 csum = ext_pi_crc64(0, iter->data_buf, iter->interval);
 279                 if (offset)
 280                         csum = ext_pi_crc64(be64_to_cpu(csum), iter->prot_buf,
 281                                             offset);
 282
 283                 if (pi->guard_tag != csum) {
 284                         pr_err("%s: guard tag error at sector %llu " \
 285                                "(rcvd %016llx, want %016llx)\n",
 286                                 iter->disk_name, (unsigned long long)iter->seed,
 287                                 be64_to_cpu(pi->guard_tag), be64_to_cpu(csum));
 288                         return BLK_STS_PROTECTION;
 289                 }
 290
 291 next:
 292                 iter->data_buf += iter->interval;
 293                 iter->prot_buf += bi->tuple_size;
 294                 iter->seed++;
 295         }
 296
 297         return BLK_STS_OK;
 298 }
 299
 300 static void ext_pi_type1_prepare(struct request *rq)
 301 {
 302         struct blk_integrity *bi = &rq->q->limits.integrity;
 303         const int tuple_sz = bi->tuple_size;
 304         u64 ref_tag = ext_pi_ref_tag(rq);
 305         u8 offset = bi->pi_offset;
 306         struct bio *bio;
 307
 308         __rq_for_each_bio(bio, rq) {
 309                 struct bio_integrity_payload *bip = bio_integrity(bio);
 310                 u64 virt = lower_48_bits(bip_get_seed(bip));
 311                 struct bio_vec iv;
 312                 struct bvec_iter iter;
 313
 314                 /* Already remapped? */
 315                 if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
 316                         break;
 317
 318                 bip_for_each_vec(iv, bip, iter) {
 319                         unsigned int j;
 320                         void *p;
 321
 322                         p = bvec_kmap_local(&iv);
 323                         for (j = 0; j < iv.bv_len; j += tuple_sz) {
 324                                 struct crc64_pi_tuple *pi = p +  offset;
 325                                 u64 ref = get_unaligned_be48(pi->ref_tag);
 326
 327                                 if (ref == virt)
 328                                         put_unaligned_be48(ref_tag, pi->ref_tag);
 329                                 virt++;
 330                                 ref_tag++;
 331                                 p += tuple_sz;
 332                         }
 333                         kunmap_local(p);
 334                 }
 335
 336                 bip->bip_flags |= BIP_MAPPED_INTEGRITY;
 337         }
 338 }
 339
 340 static void ext_pi_type1_complete(struct request *rq, unsigned int nr_bytes)
 341 {
 342         struct blk_integrity *bi = &rq->q->limits.integrity;
 343         unsigned intervals = nr_bytes >> bi->interval_exp;
 344         const int tuple_sz = bi->tuple_size;
 345         u64 ref_tag = ext_pi_ref_tag(rq);
 346         u8 offset = bi->pi_offset;
 347         struct bio *bio;
 348
 349         __rq_for_each_bio(bio, rq) {
 350                 struct bio_integrity_payload *bip = bio_integrity(bio);
 351                 u64 virt = lower_48_bits(bip_get_seed(bip));
 352                 struct bio_vec iv;
 353                 struct bvec_iter iter;
 354
 355                 bip_for_each_vec(iv, bip, iter) {
 356                         unsigned int j;
 357                         void *p;
 358
 359                         p = bvec_kmap_local(&iv);
 360                         for (j = 0; j < iv.bv_len && intervals; j += tuple_sz) {
 361                                 struct crc64_pi_tuple *pi = p + offset;
 362                                 u64 ref = get_unaligned_be48(pi->ref_tag);
 363
 364                                 if (ref == ref_tag)
 365                                         put_unaligned_be48(virt, pi->ref_tag);
 366                                 virt++;
 367                                 ref_tag++;
 368                                 intervals--;
 369                                 p += tuple_sz;
 370                         }
 371                         kunmap_local(p);
 372                 }
 373         }
 374 }
 375
 376 void blk_integrity_generate(struct bio *bio)
 377 {
 378         struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
 379         struct bio_integrity_payload *bip = bio_integrity(bio);
 380         struct blk_integrity_iter iter;
 381         struct bvec_iter bviter;
 382         struct bio_vec bv;
 383
 384         iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
 385         iter.interval = 1 << bi->interval_exp;
 386         iter.seed = bio->bi_iter.bi_sector;
 387         iter.prot_buf = bvec_virt(bip->bip_vec);
 388         bio_for_each_segment(bv, bio, bviter) {
 389                 void *kaddr = bvec_kmap_local(&bv);
 390
 391                 iter.data_buf = kaddr;
 392                 iter.data_size = bv.bv_len;
 393                 switch (bi->csum_type) {
 394                 case BLK_INTEGRITY_CSUM_CRC64:
 395                         ext_pi_crc64_generate(&iter, bi);
 396                         break;
 397                 case BLK_INTEGRITY_CSUM_CRC:
 398                 case BLK_INTEGRITY_CSUM_IP:
 399                         t10_pi_generate(&iter, bi);
 400                         break;
 401                 default:
 402                         break;
 403                 }
 404                 kunmap_local(kaddr);
 405         }
 406 }
 407
 408 void blk_integrity_verify(struct bio *bio)
 409 {
 410         struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
 411         struct bio_integrity_payload *bip = bio_integrity(bio);
 412         struct blk_integrity_iter iter;
 413         struct bvec_iter bviter;
 414         struct bio_vec bv;
 415
 416         /*
 417          * At the moment verify is called bi_iter has been advanced during split
 418          * and completion, so use the copy created during submission here.
 419          */
 420         iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
 421         iter.interval = 1 << bi->interval_exp;
 422         iter.seed = bip->bio_iter.bi_sector;
 423         iter.prot_buf = bvec_virt(bip->bip_vec);
 424         __bio_for_each_segment(bv, bio, bviter, bip->bio_iter) {
 425                 void *kaddr = bvec_kmap_local(&bv);
 426                 blk_status_t ret = BLK_STS_OK;
 427
 428                 iter.data_buf = kaddr;
 429                 iter.data_size = bv.bv_len;
 430                 switch (bi->csum_type) {
 431                 case BLK_INTEGRITY_CSUM_CRC64:
 432                         ret = ext_pi_crc64_verify(&iter, bi);
 433                         break;
 434                 case BLK_INTEGRITY_CSUM_CRC:
 435                 case BLK_INTEGRITY_CSUM_IP:
 436                         ret = t10_pi_verify(&iter, bi);
 437                         break;
 438                 default:
 439                         break;
 440                 }
 441                 kunmap_local(kaddr);
 442
 443                 if (ret) {
 444                         bio->bi_status = ret;
 445                         return;
 446                 }
 447         }
 448 }
 449
 450 void blk_integrity_prepare(struct request *rq)
 451 {
 452         struct blk_integrity *bi = &rq->q->limits.integrity;
 453
 454         if (!(bi->flags & BLK_INTEGRITY_REF_TAG))
 455                 return;
 456
 457         if (bi->csum_type == BLK_INTEGRITY_CSUM_CRC64)
 458                 ext_pi_type1_prepare(rq);
 459         else
 460                 t10_pi_type1_prepare(rq);
 461 }
 462
 463 void blk_integrity_complete(struct request *rq, unsigned int nr_bytes)
 464 {
 465         struct blk_integrity *bi = &rq->q->limits.integrity;
 466
 467         if (!(bi->flags & BLK_INTEGRITY_REF_TAG))
 468                 return;
 469
 470         if (bi->csum_type == BLK_INTEGRITY_CSUM_CRC64)
 471                 ext_pi_type1_complete(rq, nr_bytes);
 472         else
 473                 t10_pi_type1_complete(rq, nr_bytes);
 474 }
 475
 476 MODULE_DESCRIPTION("T10 Protection Information module");
 477 MODULE_LICENSE("GPL");