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