lib/efi_loader/efi_device_path.c

   1 /*
   2  * EFI device path from u-boot device-model mapping
   3  *
   4  * (C) Copyright 2017 Rob Clark
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #include <common.h>
  10 #include <blk.h>
  11 #include <dm.h>
  12 #include <usb.h>
  13 #include <mmc.h>
  14 #include <efi_loader.h>
  15 #include <inttypes.h>
  16 #include <part.h>
  17
  18 /* template END node: */
  19 static const struct efi_device_path END = {
  20         .type     = DEVICE_PATH_TYPE_END,
  21         .sub_type = DEVICE_PATH_SUB_TYPE_END,
  22         .length   = sizeof(END),
  23 };
  24
  25 #define U_BOOT_GUID \
  26         EFI_GUID(0xe61d73b9, 0xa384, 0x4acc, \
  27                  0xae, 0xab, 0x82, 0xe8, 0x28, 0xf3, 0x62, 0x8b)
  28
  29 /* template ROOT node: */
  30 static const struct efi_device_path_vendor ROOT = {
  31         .dp = {
  32                 .type     = DEVICE_PATH_TYPE_HARDWARE_DEVICE,
  33                 .sub_type = DEVICE_PATH_SUB_TYPE_VENDOR,
  34                 .length   = sizeof(ROOT),
  35         },
  36         .guid = U_BOOT_GUID,
  37 };
  38
  39 #if defined(CONFIG_DM_MMC) && defined(CONFIG_MMC)
  40 /*
  41  * Determine if an MMC device is an SD card.
  42  *
  43  * @desc        block device descriptor
  44  * @return      true if the device is an SD card
  45  */
  46 static bool is_sd(struct blk_desc *desc)
  47 {
  48         struct mmc *mmc = find_mmc_device(desc->devnum);
  49
  50         if (!mmc)
  51                 return false;
  52
  53         return IS_SD(mmc) != 0U;
  54 }
  55 #endif
  56
  57 static void *dp_alloc(size_t sz)
  58 {
  59         void *buf;
  60
  61         if (efi_allocate_pool(EFI_ALLOCATE_ANY_PAGES, sz, &buf) != EFI_SUCCESS)
  62                 return NULL;
  63
  64         return buf;
  65 }
  66
  67 /*
  68  * Iterate to next block in device-path, terminating (returning NULL)
  69  * at /End* node.
  70  */
  71 struct efi_device_path *efi_dp_next(const struct efi_device_path *dp)
  72 {
  73         if (dp == NULL)
  74                 return NULL;
  75         if (dp->type == DEVICE_PATH_TYPE_END)
  76                 return NULL;
  77         dp = ((void *)dp) + dp->length;
  78         if (dp->type == DEVICE_PATH_TYPE_END)
  79                 return NULL;
  80         return (struct efi_device_path *)dp;
  81 }
  82
  83 /*
  84  * Compare two device-paths, stopping when the shorter of the two hits
  85  * an End* node.  This is useful to, for example, compare a device-path
  86  * representing a device with one representing a file on the device, or
  87  * a device with a parent device.
  88  */
  89 int efi_dp_match(const struct efi_device_path *a,
  90                  const struct efi_device_path *b)
  91 {
  92         while (1) {
  93                 int ret;
  94
  95                 ret = memcmp(&a->length, &b->length, sizeof(a->length));
  96                 if (ret)
  97                         return ret;
  98
  99                 ret = memcmp(a, b, a->length);
 100                 if (ret)
 101                         return ret;
 102
 103                 a = efi_dp_next(a);
 104                 b = efi_dp_next(b);
 105
 106                 if (!a || !b)
 107                         return 0;
 108         }
 109 }
 110
 111
 112 /*
 113  * See UEFI spec (section 3.1.2, about short-form device-paths..
 114  * tl;dr: we can have a device-path that starts with a USB WWID
 115  * or USB Class node, and a few other cases which don't encode
 116  * the full device path with bus hierarchy:
 117  *
 118  *   - MESSAGING:USB_WWID
 119  *   - MESSAGING:USB_CLASS
 120  *   - MEDIA:FILE_PATH
 121  *   - MEDIA:HARD_DRIVE
 122  *   - MESSAGING:URI
 123  */
 124 static struct efi_device_path *shorten_path(struct efi_device_path *dp)
 125 {
 126         while (dp) {
 127                 /*
 128                  * TODO: Add MESSAGING:USB_WWID and MESSAGING:URI..
 129                  * in practice fallback.efi just uses MEDIA:HARD_DRIVE
 130                  * so not sure when we would see these other cases.
 131                  */
 132                 if (EFI_DP_TYPE(dp, MESSAGING_DEVICE, MSG_USB_CLASS) ||
 133                     EFI_DP_TYPE(dp, MEDIA_DEVICE, HARD_DRIVE_PATH) ||
 134                     EFI_DP_TYPE(dp, MEDIA_DEVICE, FILE_PATH))
 135                         return dp;
 136
 137                 dp = efi_dp_next(dp);
 138         }
 139
 140         return dp;
 141 }
 142
 143 static struct efi_object *find_obj(struct efi_device_path *dp, bool short_path,
 144                                    struct efi_device_path **rem)
 145 {
 146         struct efi_object *efiobj;
 147         unsigned int dp_size = efi_dp_size(dp);
 148
 149         list_for_each_entry(efiobj, &efi_obj_list, link) {
 150                 struct efi_handler *handler;
 151                 struct efi_device_path *obj_dp;
 152                 efi_status_t ret;
 153
 154                 ret = efi_search_protocol(efiobj->handle,
 155                                           &efi_guid_device_path, &handler);
 156                 if (ret != EFI_SUCCESS)
 157                         continue;
 158                 obj_dp = handler->protocol_interface;
 159
 160                 do {
 161                         if (efi_dp_match(dp, obj_dp) == 0) {
 162                                 if (rem) {
 163                                         /*
 164                                          * Allow partial matches, but inform
 165                                          * the caller.
 166                                          */
 167                                         *rem = ((void *)dp) +
 168                                                 efi_dp_size(obj_dp);
 169                                         return efiobj;
 170                                 } else {
 171                                         /* Only return on exact matches */
 172                                         if (efi_dp_size(obj_dp) == dp_size)
 173                                                 return efiobj;
 174                                 }
 175                         }
 176
 177                         obj_dp = shorten_path(efi_dp_next(obj_dp));
 178                 } while (short_path && obj_dp);
 179         }
 180
 181         return NULL;
 182 }
 183
 184
 185 /*
 186  * Find an efiobj from device-path, if 'rem' is not NULL, returns the
 187  * remaining part of the device path after the matched object.
 188  */
 189 struct efi_object *efi_dp_find_obj(struct efi_device_path *dp,
 190                                    struct efi_device_path **rem)
 191 {
 192         struct efi_object *efiobj;
 193
 194         /* Search for an exact match first */
 195         efiobj = find_obj(dp, false, NULL);
 196
 197         /* Then for a fuzzy match */
 198         if (!efiobj)
 199                 efiobj = find_obj(dp, false, rem);
 200
 201         /* And now for a fuzzy short match */
 202         if (!efiobj)
 203                 efiobj = find_obj(dp, true, rem);
 204
 205         return efiobj;
 206 }
 207
 208 /* return size not including End node: */
 209 unsigned efi_dp_size(const struct efi_device_path *dp)
 210 {
 211         unsigned sz = 0;
 212
 213         while (dp) {
 214                 sz += dp->length;
 215                 dp = efi_dp_next(dp);
 216         }
 217
 218         return sz;
 219 }
 220
 221 struct efi_device_path *efi_dp_dup(const struct efi_device_path *dp)
 222 {
 223         struct efi_device_path *ndp;
 224         unsigned sz = efi_dp_size(dp) + sizeof(END);
 225
 226         if (!dp)
 227                 return NULL;
 228
 229         ndp = dp_alloc(sz);
 230         memcpy(ndp, dp, sz);
 231
 232         return ndp;
 233 }
 234
 235 struct efi_device_path *efi_dp_append(const struct efi_device_path *dp1,
 236                                       const struct efi_device_path *dp2)
 237 {
 238         struct efi_device_path *ret;
 239
 240         if (!dp1) {
 241                 ret = efi_dp_dup(dp2);
 242         } else if (!dp2) {
 243                 ret = efi_dp_dup(dp1);
 244         } else {
 245                 /* both dp1 and dp2 are non-null */
 246                 unsigned sz1 = efi_dp_size(dp1);
 247                 unsigned sz2 = efi_dp_size(dp2);
 248                 void *p = dp_alloc(sz1 + sz2 + sizeof(END));
 249                 memcpy(p, dp1, sz1);
 250                 memcpy(p + sz1, dp2, sz2);
 251                 memcpy(p + sz1 + sz2, &END, sizeof(END));
 252                 ret = p;
 253         }
 254
 255         return ret;
 256 }
 257
 258 struct efi_device_path *efi_dp_append_node(const struct efi_device_path *dp,
 259                                            const struct efi_device_path *node)
 260 {
 261         struct efi_device_path *ret;
 262
 263         if (!node && !dp) {
 264                 ret = efi_dp_dup(&END);
 265         } else if (!node) {
 266                 ret = efi_dp_dup(dp);
 267         } else if (!dp) {
 268                 unsigned sz = node->length;
 269                 void *p = dp_alloc(sz + sizeof(END));
 270                 memcpy(p, node, sz);
 271                 memcpy(p + sz, &END, sizeof(END));
 272                 ret = p;
 273         } else {
 274                 /* both dp and node are non-null */
 275                 unsigned sz = efi_dp_size(dp);
 276                 void *p = dp_alloc(sz + node->length + sizeof(END));
 277                 memcpy(p, dp, sz);
 278                 memcpy(p + sz, node, node->length);
 279                 memcpy(p + sz + node->length, &END, sizeof(END));
 280                 ret = p;
 281         }
 282
 283         return ret;
 284 }
 285
 286 #ifdef CONFIG_DM
 287 /* size of device-path not including END node for device and all parents
 288  * up to the root device.
 289  */
 290 static unsigned dp_size(struct udevice *dev)
 291 {
 292         if (!dev || !dev->driver)
 293                 return sizeof(ROOT);
 294
 295         switch (dev->driver->id) {
 296         case UCLASS_ROOT:
 297         case UCLASS_SIMPLE_BUS:
 298                 /* stop traversing parents at this point: */
 299                 return sizeof(ROOT);
 300         case UCLASS_MMC:
 301                 return dp_size(dev->parent) +
 302                         sizeof(struct efi_device_path_sd_mmc_path);
 303         case UCLASS_MASS_STORAGE:
 304         case UCLASS_USB_HUB:
 305                 return dp_size(dev->parent) +
 306                         sizeof(struct efi_device_path_usb_class);
 307         default:
 308                 /* just skip over unknown classes: */
 309                 return dp_size(dev->parent);
 310         }
 311 }
 312
 313 static void *dp_fill(void *buf, struct udevice *dev)
 314 {
 315         if (!dev || !dev->driver)
 316                 return buf;
 317
 318         switch (dev->driver->id) {
 319         case UCLASS_ROOT:
 320         case UCLASS_SIMPLE_BUS: {
 321                 /* stop traversing parents at this point: */
 322                 struct efi_device_path_vendor *vdp = buf;
 323                 *vdp = ROOT;
 324                 return &vdp[1];
 325         }
 326 #if defined(CONFIG_DM_MMC) && defined(CONFIG_MMC)
 327         case UCLASS_MMC: {
 328                 struct efi_device_path_sd_mmc_path *sddp =
 329                         dp_fill(buf, dev->parent);
 330                 struct mmc *mmc = mmc_get_mmc_dev(dev);
 331                 struct blk_desc *desc = mmc_get_blk_desc(mmc);
 332
 333                 sddp->dp.type     = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 334                 sddp->dp.sub_type = is_sd(desc) ?
 335                         DEVICE_PATH_SUB_TYPE_MSG_SD :
 336                         DEVICE_PATH_SUB_TYPE_MSG_MMC;
 337                 sddp->dp.length   = sizeof(*sddp);
 338                 sddp->slot_number = dev->seq;
 339
 340                 return &sddp[1];
 341         }
 342 #endif
 343         case UCLASS_MASS_STORAGE:
 344         case UCLASS_USB_HUB: {
 345                 struct efi_device_path_usb_class *udp =
 346                         dp_fill(buf, dev->parent);
 347                 struct usb_device *udev = dev_get_parent_priv(dev);
 348                 struct usb_device_descriptor *desc = &udev->descriptor;
 349
 350                 udp->dp.type     = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 351                 udp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_USB_CLASS;
 352                 udp->dp.length   = sizeof(*udp);
 353                 udp->vendor_id   = desc->idVendor;
 354                 udp->product_id  = desc->idProduct;
 355                 udp->device_class    = desc->bDeviceClass;
 356                 udp->device_subclass = desc->bDeviceSubClass;
 357                 udp->device_protocol = desc->bDeviceProtocol;
 358
 359                 return &udp[1];
 360         }
 361         default:
 362                 debug("unhandled device class: %s (%u)\n",
 363                       dev->name, dev->driver->id);
 364                 return dp_fill(buf, dev->parent);
 365         }
 366 }
 367
 368 /* Construct a device-path from a device: */
 369 struct efi_device_path *efi_dp_from_dev(struct udevice *dev)
 370 {
 371         void *buf, *start;
 372
 373         start = buf = dp_alloc(dp_size(dev) + sizeof(END));
 374         buf = dp_fill(buf, dev);
 375         *((struct efi_device_path *)buf) = END;
 376
 377         return start;
 378 }
 379 #endif
 380
 381 static unsigned dp_part_size(struct blk_desc *desc, int part)
 382 {
 383         unsigned dpsize;
 384
 385 #ifdef CONFIG_BLK
 386         dpsize = dp_size(desc->bdev->parent);
 387 #else
 388         dpsize = sizeof(ROOT) + sizeof(struct efi_device_path_usb);
 389 #endif
 390
 391         if (part == 0) /* the actual disk, not a partition */
 392                 return dpsize;
 393
 394         if (desc->part_type == PART_TYPE_ISO)
 395                 dpsize += sizeof(struct efi_device_path_cdrom_path);
 396         else
 397                 dpsize += sizeof(struct efi_device_path_hard_drive_path);
 398
 399         return dpsize;
 400 }
 401
 402 /*
 403  * Create a device path for a block device or one of its partitions.
 404  *
 405  * @buf         buffer to which the device path is wirtten
 406  * @desc        block device descriptor
 407  * @part        partition number, 0 identifies a block device
 408  */
 409 static void *dp_part_fill(void *buf, struct blk_desc *desc, int part)
 410 {
 411         disk_partition_t info;
 412
 413 #ifdef CONFIG_BLK
 414         buf = dp_fill(buf, desc->bdev->parent);
 415 #else
 416         /*
 417          * We *could* make a more accurate path, by looking at if_type
 418          * and handling all the different cases like we do for non-
 419          * legacy (ie CONFIG_BLK=y) case.  But most important thing
 420          * is just to have a unique device-path for if_type+devnum.
 421          * So map things to a fictitious USB device.
 422          */
 423         struct efi_device_path_usb *udp;
 424
 425         memcpy(buf, &ROOT, sizeof(ROOT));
 426         buf += sizeof(ROOT);
 427
 428         udp = buf;
 429         udp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 430         udp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_USB;
 431         udp->dp.length = sizeof(*udp);
 432         udp->parent_port_number = desc->if_type;
 433         udp->usb_interface = desc->devnum;
 434         buf = &udp[1];
 435 #endif
 436
 437         if (part == 0) /* the actual disk, not a partition */
 438                 return buf;
 439
 440         part_get_info(desc, part, &info);
 441
 442         if (desc->part_type == PART_TYPE_ISO) {
 443                 struct efi_device_path_cdrom_path *cddp = buf;
 444
 445                 cddp->boot_entry = part;
 446                 cddp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
 447                 cddp->dp.sub_type = DEVICE_PATH_SUB_TYPE_CDROM_PATH;
 448                 cddp->dp.length = sizeof(*cddp);
 449                 cddp->partition_start = info.start;
 450                 cddp->partition_end = info.size;
 451
 452                 buf = &cddp[1];
 453         } else {
 454                 struct efi_device_path_hard_drive_path *hddp = buf;
 455
 456                 hddp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
 457                 hddp->dp.sub_type = DEVICE_PATH_SUB_TYPE_HARD_DRIVE_PATH;
 458                 hddp->dp.length = sizeof(*hddp);
 459                 hddp->partition_number = part;
 460                 hddp->partition_start = info.start;
 461                 hddp->partition_end = info.size;
 462                 if (desc->part_type == PART_TYPE_EFI)
 463                         hddp->partmap_type = 2;
 464                 else
 465                         hddp->partmap_type = 1;
 466
 467                 switch (desc->sig_type) {
 468                 case SIG_TYPE_NONE:
 469                 default:
 470                         hddp->signature_type = 0;
 471                         memset(hddp->partition_signature, 0,
 472                                sizeof(hddp->partition_signature));
 473                         break;
 474                 case SIG_TYPE_MBR:
 475                         hddp->signature_type = 1;
 476                         memset(hddp->partition_signature, 0,
 477                                sizeof(hddp->partition_signature));
 478                         memcpy(hddp->partition_signature, &desc->mbr_sig,
 479                                sizeof(desc->mbr_sig));
 480                         break;
 481                 case SIG_TYPE_GUID:
 482                         hddp->signature_type = 2;
 483                         memcpy(hddp->partition_signature, &desc->guid_sig,
 484                                sizeof(hddp->partition_signature));
 485                         break;
 486                 }
 487
 488                 buf = &hddp[1];
 489         }
 490
 491         return buf;
 492 }
 493
 494
 495 /* Construct a device-path from a partition on a blk device: */
 496 struct efi_device_path *efi_dp_from_part(struct blk_desc *desc, int part)
 497 {
 498         void *buf, *start;
 499
 500         start = buf = dp_alloc(dp_part_size(desc, part) + sizeof(END));
 501
 502         buf = dp_part_fill(buf, desc, part);
 503
 504         *((struct efi_device_path *)buf) = END;
 505
 506         return start;
 507 }
 508
 509 /* convert path to an UEFI style path (ie. DOS style backslashes and utf16) */
 510 static void path_to_uefi(u16 *uefi, const char *path)
 511 {
 512         while (*path) {
 513                 char c = *(path++);
 514                 if (c == '/')
 515                         c = '\\';
 516                 *(uefi++) = c;
 517         }
 518         *uefi = '\0';
 519 }
 520
 521 /*
 522  * If desc is NULL, this creates a path with only the file component,
 523  * otherwise it creates a full path with both device and file components
 524  */
 525 struct efi_device_path *efi_dp_from_file(struct blk_desc *desc, int part,
 526                 const char *path)
 527 {
 528         struct efi_device_path_file_path *fp;
 529         void *buf, *start;
 530         unsigned dpsize = 0, fpsize;
 531
 532         if (desc)
 533                 dpsize = dp_part_size(desc, part);
 534
 535         fpsize = sizeof(struct efi_device_path) + 2 * (strlen(path) + 1);
 536         dpsize += fpsize;
 537
 538         start = buf = dp_alloc(dpsize + sizeof(END));
 539
 540         if (desc)
 541                 buf = dp_part_fill(buf, desc, part);
 542
 543         /* add file-path: */
 544         fp = buf;
 545         fp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
 546         fp->dp.sub_type = DEVICE_PATH_SUB_TYPE_FILE_PATH;
 547         fp->dp.length = fpsize;
 548         path_to_uefi(fp->str, path);
 549         buf += fpsize;
 550
 551         *((struct efi_device_path *)buf) = END;
 552
 553         return start;
 554 }
 555
 556 #ifdef CONFIG_NET
 557 struct efi_device_path *efi_dp_from_eth(void)
 558 {
 559         struct efi_device_path_mac_addr *ndp;
 560         void *buf, *start;
 561         unsigned dpsize = 0;
 562
 563         assert(eth_get_dev());
 564
 565 #ifdef CONFIG_DM_ETH
 566         dpsize += dp_size(eth_get_dev());
 567 #else
 568         dpsize += sizeof(ROOT);
 569 #endif
 570         dpsize += sizeof(*ndp);
 571
 572         start = buf = dp_alloc(dpsize + sizeof(END));
 573
 574 #ifdef CONFIG_DM_ETH
 575         buf = dp_fill(buf, eth_get_dev());
 576 #else
 577         memcpy(buf, &ROOT, sizeof(ROOT));
 578         buf += sizeof(ROOT);
 579 #endif
 580
 581         ndp = buf;
 582         ndp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 583         ndp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_MAC_ADDR;
 584         ndp->dp.length = sizeof(*ndp);
 585         memcpy(ndp->mac.addr, eth_get_ethaddr(), ARP_HLEN);
 586         buf = &ndp[1];
 587
 588         *((struct efi_device_path *)buf) = END;
 589
 590         return start;
 591 }
 592 #endif
 593
 594 /* Construct a device-path for memory-mapped image */
 595 struct efi_device_path *efi_dp_from_mem(uint32_t memory_type,
 596                                         uint64_t start_address,
 597                                         uint64_t end_address)
 598 {
 599         struct efi_device_path_memory *mdp;
 600         void *buf, *start;
 601
 602         start = buf = dp_alloc(sizeof(*mdp) + sizeof(END));
 603
 604         mdp = buf;
 605         mdp->dp.type = DEVICE_PATH_TYPE_HARDWARE_DEVICE;
 606         mdp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MEMORY;
 607         mdp->dp.length = sizeof(*mdp);
 608         mdp->memory_type = memory_type;
 609         mdp->start_address = start_address;
 610         mdp->end_address = end_address;
 611         buf = &mdp[1];
 612
 613         *((struct efi_device_path *)buf) = END;
 614
 615         return start;
 616 }
 617
 618 /*
 619  * Helper to split a full device path (containing both device and file
 620  * parts) into it's constituent parts.
 621  */
 622 void efi_dp_split_file_path(struct efi_device_path *full_path,
 623                             struct efi_device_path **device_path,
 624                             struct efi_device_path **file_path)
 625 {
 626         struct efi_device_path *p, *dp, *fp;
 627
 628         dp = efi_dp_dup(full_path);
 629         p = dp;
 630         while (!EFI_DP_TYPE(p, MEDIA_DEVICE, FILE_PATH))
 631                 p = efi_dp_next(p);
 632         fp = efi_dp_dup(p);
 633
 634         p->type = DEVICE_PATH_TYPE_END;
 635         p->sub_type = DEVICE_PATH_SUB_TYPE_END;
 636         p->length = sizeof(*p);
 637
 638         *device_path = dp;
 639         *file_path = fp;
 640 }