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