pc-bios/s390-ccw/bootmap.c

   1 /*
   2  * QEMU S390 bootmap interpreter
   3  *
   4  * Copyright (c) 2009 Alexander Graf <agraf@suse.de>
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or (at
   7  * your option) any later version. See the COPYING file in the top-level
   8  * directory.
   9  */
  10
  11 #include "libc.h"
  12 #include "s390-ccw.h"
  13 #include "bootmap.h"
  14 #include "virtio.h"
  15 #include "bswap.h"
  16
  17 #ifdef DEBUG
  18 /* #define DEBUG_FALLBACK */
  19 #endif
  20
  21 #ifdef DEBUG_FALLBACK
  22 #define dputs(txt) \
  23     do { sclp_print("zipl: " txt); } while (0)
  24 #else
  25 #define dputs(fmt, ...) \
  26     do { } while (0)
  27 #endif
  28
  29 /* Scratch space */
  30 static uint8_t sec[MAX_SECTOR_SIZE*4] __attribute__((__aligned__(PAGE_SIZE)));
  31
  32 typedef struct ResetInfo {
  33     uint32_t ipl_mask;
  34     uint32_t ipl_addr;
  35     uint32_t ipl_continue;
  36 } ResetInfo;
  37
  38 static ResetInfo save;
  39
  40 static void jump_to_IPL_2(void)
  41 {
  42     ResetInfo *current = 0;
  43
  44     void (*ipl)(void) = (void *) (uint64_t) current->ipl_continue;
  45     *current = save;
  46     ipl(); /* should not return */
  47 }
  48
  49 static void jump_to_IPL_code(uint64_t address)
  50 {
  51     /* store the subsystem information _after_ the bootmap was loaded */
  52     write_subsystem_identification();
  53     /*
  54      * The IPL PSW is at address 0. We also must not overwrite the
  55      * content of non-BIOS memory after we loaded the guest, so we
  56      * save the original content and restore it in jump_to_IPL_2.
  57      */
  58     ResetInfo *current = 0;
  59
  60     save = *current;
  61     current->ipl_addr = (uint32_t) (uint64_t) &jump_to_IPL_2;
  62     current->ipl_continue = address & 0x7fffffff;
  63
  64     debug_print_int("set IPL addr to", current->ipl_continue);
  65
  66     /* Ensure the guest output starts fresh */
  67     sclp_print("\n");
  68
  69     /*
  70      * HACK ALERT.
  71      * We use the load normal reset to keep r15 unchanged. jump_to_IPL_2
  72      * can then use r15 as its stack pointer.
  73      */
  74     asm volatile("lghi 1,1\n\t"
  75                  "diag 1,1,0x308\n\t"
  76                  : : : "1", "memory");
  77     panic("\n! IPL returns !\n");
  78 }
  79
  80 /***********************************************************************
  81  * IPL an ECKD DASD (CDL or LDL/CMS format)
  82  */
  83
  84 static unsigned char _bprs[8*1024]; /* guessed "max" ECKD sector size */
  85 static const int max_bprs_entries = sizeof(_bprs) / sizeof(ExtEckdBlockPtr);
  86
  87 static inline void verify_boot_info(BootInfo *bip)
  88 {
  89     IPL_assert(magic_match(bip->magic, ZIPL_MAGIC), "No zIPL sig in BootInfo");
  90     IPL_assert(bip->version == BOOT_INFO_VERSION, "Wrong zIPL version");
  91     IPL_assert(bip->bp_type == BOOT_INFO_BP_TYPE_IPL, "DASD is not for IPL");
  92     IPL_assert(bip->dev_type == BOOT_INFO_DEV_TYPE_ECKD, "DASD is not ECKD");
  93     IPL_assert(bip->flags == BOOT_INFO_FLAGS_ARCH, "Not for this arch");
  94     IPL_assert(block_size_ok(bip->bp.ipl.bm_ptr.eckd.bptr.size),
  95                "Bad block size in zIPL section of the 1st record.");
  96 }
  97
  98 static block_number_t eckd_block_num(BootMapPointer *p)
  99 {
 100     const uint64_t sectors = virtio_get_sectors();
 101     const uint64_t heads = virtio_get_heads();
 102     const uint64_t cylinder = p->eckd.cylinder
 103                             + ((p->eckd.head & 0xfff0) << 12);
 104     const uint64_t head = p->eckd.head & 0x000f;
 105     const block_number_t block = sectors * heads * cylinder
 106                                + sectors * head
 107                                + p->eckd.sector
 108                                - 1; /* block nr starts with zero */
 109     return block;
 110 }
 111
 112 static bool eckd_valid_address(BootMapPointer *p)
 113 {
 114     const uint64_t head = p->eckd.head & 0x000f;
 115
 116     if (head >= virtio_get_heads()
 117         ||  p->eckd.sector > virtio_get_sectors()
 118         ||  p->eckd.sector <= 0) {
 119         return false;
 120     }
 121
 122     if (!virtio_guessed_disk_nature() &&
 123         eckd_block_num(p) >= virtio_get_blocks()) {
 124         return false;
 125     }
 126
 127     return true;
 128 }
 129
 130 static block_number_t load_eckd_segments(block_number_t blk, uint64_t *address)
 131 {
 132     block_number_t block_nr;
 133     int j, rc;
 134     BootMapPointer *bprs = (void *)_bprs;
 135     bool more_data;
 136
 137     memset(_bprs, FREE_SPACE_FILLER, sizeof(_bprs));
 138     read_block(blk, bprs, "BPRS read failed");
 139
 140     do {
 141         more_data = false;
 142         for (j = 0;; j++) {
 143             block_nr = eckd_block_num((void *)&(bprs[j].xeckd));
 144             if (is_null_block_number(block_nr)) { /* end of chunk */
 145                 break;
 146             }
 147
 148             /* we need the updated blockno for the next indirect entry
 149              * in the chain, but don't want to advance address
 150              */
 151             if (j == (max_bprs_entries - 1)) {
 152                 break;
 153             }
 154
 155             IPL_assert(block_size_ok(bprs[j].xeckd.bptr.size),
 156                        "bad chunk block size");
 157             IPL_assert(eckd_valid_address(&bprs[j]), "bad chunk ECKD addr");
 158
 159             if ((bprs[j].xeckd.bptr.count == 0) && unused_space(&(bprs[j+1]),
 160                 sizeof(EckdBlockPtr))) {
 161                 /* This is a "continue" pointer.
 162                  * This ptr should be the last one in the current
 163                  * script section.
 164                  * I.e. the next ptr must point to the unused memory area
 165                  */
 166                 memset(_bprs, FREE_SPACE_FILLER, sizeof(_bprs));
 167                 read_block(block_nr, bprs, "BPRS continuation read failed");
 168                 more_data = true;
 169                 break;
 170             }
 171
 172             /* Load (count+1) blocks of code at (block_nr)
 173              * to memory (address).
 174              */
 175             rc = virtio_read_many(block_nr, (void *)(*address),
 176                                   bprs[j].xeckd.bptr.count+1);
 177             IPL_assert(rc == 0, "code chunk read failed");
 178
 179             *address += (bprs[j].xeckd.bptr.count+1) * virtio_get_block_size();
 180         }
 181     } while (more_data);
 182     return block_nr;
 183 }
 184
 185 static void run_eckd_boot_script(block_number_t mbr_block_nr)
 186 {
 187     int i;
 188     unsigned int loadparm = get_loadparm_index();
 189     block_number_t block_nr;
 190     uint64_t address;
 191     ScsiMbr *bte = (void *)sec; /* Eckd bootmap table entry */
 192     BootMapScript *bms = (void *)sec;
 193
 194     debug_print_int("loadparm", loadparm);
 195     IPL_assert(loadparm < 31, "loadparm value greater than"
 196                " maximum number of boot entries allowed");
 197
 198     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 199     read_block(mbr_block_nr, sec, "Cannot read MBR");
 200
 201     block_nr = eckd_block_num((void *)&(bte->blockptr[loadparm]));
 202     IPL_assert(block_nr != -1, "No Boot Map");
 203
 204     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 205     read_block(block_nr, sec, "Cannot read Boot Map Script");
 206
 207     for (i = 0; bms->entry[i].type == BOOT_SCRIPT_LOAD; i++) {
 208         address = bms->entry[i].address.load_address;
 209         block_nr = eckd_block_num(&(bms->entry[i].blkptr));
 210
 211         do {
 212             block_nr = load_eckd_segments(block_nr, &address);
 213         } while (block_nr != -1);
 214     }
 215
 216     IPL_assert(bms->entry[i].type == BOOT_SCRIPT_EXEC,
 217                "Unknown script entry type");
 218     jump_to_IPL_code(bms->entry[i].address.load_address); /* no return */
 219 }
 220
 221 static void ipl_eckd_cdl(void)
 222 {
 223     XEckdMbr *mbr;
 224     Ipl2 *ipl2 = (void *)sec;
 225     IplVolumeLabel *vlbl = (void *)sec;
 226     block_number_t block_nr;
 227
 228     /* we have just read the block #0 and recognized it as "IPL1" */
 229     sclp_print("CDL\n");
 230
 231     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 232     read_block(1, ipl2, "Cannot read IPL2 record at block 1");
 233
 234     mbr = &ipl2->u.x.mbr;
 235     IPL_assert(magic_match(mbr, ZIPL_MAGIC), "No zIPL section in IPL2 record.");
 236     IPL_assert(block_size_ok(mbr->blockptr.xeckd.bptr.size),
 237                "Bad block size in zIPL section of IPL2 record.");
 238     IPL_assert(mbr->dev_type == DEV_TYPE_ECKD,
 239                "Non-ECKD device type in zIPL section of IPL2 record.");
 240
 241     /* save pointer to Boot Script */
 242     block_nr = eckd_block_num((void *)&(mbr->blockptr));
 243
 244     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 245     read_block(2, vlbl, "Cannot read Volume Label at block 2");
 246     IPL_assert(magic_match(vlbl->key, VOL1_MAGIC),
 247                "Invalid magic of volume label block");
 248     IPL_assert(magic_match(vlbl->f.key, VOL1_MAGIC),
 249                "Invalid magic of volser block");
 250     print_volser(vlbl->f.volser);
 251
 252     run_eckd_boot_script(block_nr);
 253     /* no return */
 254 }
 255
 256 static void print_eckd_ldl_msg(ECKD_IPL_mode_t mode)
 257 {
 258     LDL_VTOC *vlbl = (void *)sec; /* already read, 3rd block */
 259     char msg[4] = { '?', '.', '\n', '\0' };
 260
 261     sclp_print((mode == ECKD_CMS) ? "CMS" : "LDL");
 262     sclp_print(" version ");
 263     switch (vlbl->LDL_version) {
 264     case LDL1_VERSION:
 265         msg[0] = '1';
 266         break;
 267     case LDL2_VERSION:
 268         msg[0] = '2';
 269         break;
 270     default:
 271         msg[0] = vlbl->LDL_version;
 272         msg[0] &= 0x0f; /* convert EBCDIC   */
 273         msg[0] |= 0x30; /* to ASCII (digit) */
 274         msg[1] = '?';
 275         break;
 276     }
 277     sclp_print(msg);
 278     print_volser(vlbl->volser);
 279 }
 280
 281 static void ipl_eckd_ldl(ECKD_IPL_mode_t mode)
 282 {
 283     block_number_t block_nr;
 284     BootInfo *bip = (void *)(sec + 0x70); /* BootInfo is MBR for LDL */
 285
 286     if (mode != ECKD_LDL_UNLABELED) {
 287         print_eckd_ldl_msg(mode);
 288     }
 289
 290     /* DO NOT read BootMap pointer (only one, xECKD) at block #2 */
 291
 292     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 293     read_block(0, sec, "Cannot read block 0 to grab boot info.");
 294     if (mode == ECKD_LDL_UNLABELED) {
 295         if (!magic_match(bip->magic, ZIPL_MAGIC)) {
 296             return; /* not applicable layout */
 297         }
 298         sclp_print("unlabeled LDL.\n");
 299     }
 300     verify_boot_info(bip);
 301
 302     block_nr = eckd_block_num((void *)&(bip->bp.ipl.bm_ptr.eckd.bptr));
 303     run_eckd_boot_script(block_nr);
 304     /* no return */
 305 }
 306
 307 static void print_eckd_msg(void)
 308 {
 309     char msg[] = "Using ECKD scheme (block size *****), ";
 310     char *p = &msg[34], *q = &msg[30];
 311     int n = virtio_get_block_size();
 312
 313     /* Fill in the block size and show up the message */
 314     if (n > 0 && n <= 99999) {
 315         while (n) {
 316             *p-- = '0' + (n % 10);
 317             n /= 10;
 318         }
 319         while (p >= q) {
 320             *p-- = ' ';
 321         }
 322     }
 323     sclp_print(msg);
 324 }
 325
 326 static void ipl_eckd(void)
 327 {
 328     ScsiMbr *mbr = (void *)sec;
 329     LDL_VTOC *vlbl = (void *)sec;
 330
 331     print_eckd_msg();
 332
 333     /* Grab the MBR again */
 334     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 335     read_block(0, mbr, "Cannot read block 0 on DASD");
 336
 337     if (magic_match(mbr->magic, IPL1_MAGIC)) {
 338         ipl_eckd_cdl(); /* no return */
 339     }
 340
 341     /* LDL/CMS? */
 342     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 343     read_block(2, vlbl, "Cannot read block 2");
 344
 345     if (magic_match(vlbl->magic, CMS1_MAGIC)) {
 346         ipl_eckd_ldl(ECKD_CMS); /* no return */
 347     }
 348     if (magic_match(vlbl->magic, LNX1_MAGIC)) {
 349         ipl_eckd_ldl(ECKD_LDL); /* no return */
 350     }
 351
 352     ipl_eckd_ldl(ECKD_LDL_UNLABELED); /* it still may return */
 353     /*
 354      * Ok, it is not a LDL by any means.
 355      * It still might be a CDL with zero record keys for IPL1 and IPL2
 356      */
 357     ipl_eckd_cdl();
 358 }
 359
 360 /***********************************************************************
 361  * IPL a SCSI disk
 362  */
 363
 364 static void zipl_load_segment(ComponentEntry *entry)
 365 {
 366     const int max_entries = (MAX_SECTOR_SIZE / sizeof(ScsiBlockPtr));
 367     ScsiBlockPtr *bprs = (void *)sec;
 368     const int bprs_size = sizeof(sec);
 369     block_number_t blockno;
 370     uint64_t address;
 371     int i;
 372     char err_msg[] = "zIPL failed to read BPRS at 0xZZZZZZZZZZZZZZZZ";
 373     char *blk_no = &err_msg[30]; /* where to print blockno in (those ZZs) */
 374
 375     blockno = entry->data.blockno;
 376     address = entry->load_address;
 377
 378     debug_print_int("loading segment at block", blockno);
 379     debug_print_int("addr", address);
 380
 381     do {
 382         memset(bprs, FREE_SPACE_FILLER, bprs_size);
 383         fill_hex_val(blk_no, &blockno, sizeof(blockno));
 384         read_block(blockno, bprs, err_msg);
 385
 386         for (i = 0;; i++) {
 387             uint64_t *cur_desc = (void *)&bprs[i];
 388
 389             blockno = bprs[i].blockno;
 390             if (!blockno) {
 391                 break;
 392             }
 393
 394             /* we need the updated blockno for the next indirect entry in the
 395                chain, but don't want to advance address */
 396             if (i == (max_entries - 1)) {
 397                 break;
 398             }
 399
 400             if (bprs[i].blockct == 0 && unused_space(&bprs[i + 1],
 401                 sizeof(ScsiBlockPtr))) {
 402                 /* This is a "continue" pointer.
 403                  * This ptr is the last one in the current script section.
 404                  * I.e. the next ptr must point to the unused memory area.
 405                  * The blockno is not zero, so the upper loop must continue
 406                  * reading next section of BPRS.
 407                  */
 408                 break;
 409             }
 410             address = virtio_load_direct(cur_desc[0], cur_desc[1], 0,
 411                                          (void *)address);
 412             IPL_assert(address != -1, "zIPL load segment failed");
 413         }
 414     } while (blockno);
 415 }
 416
 417 /* Run a zipl program */
 418 static void zipl_run(ScsiBlockPtr *pte)
 419 {
 420     ComponentHeader *header;
 421     ComponentEntry *entry;
 422     uint8_t tmp_sec[MAX_SECTOR_SIZE];
 423
 424     read_block(pte->blockno, tmp_sec, "Cannot read header");
 425     header = (ComponentHeader *)tmp_sec;
 426
 427     IPL_assert(magic_match(tmp_sec, ZIPL_MAGIC), "No zIPL magic in header");
 428     IPL_assert(header->type == ZIPL_COMP_HEADER_IPL, "Bad header type");
 429
 430     dputs("start loading images\n");
 431
 432     /* Load image(s) into RAM */
 433     entry = (ComponentEntry *)(&header[1]);
 434     while (entry->component_type == ZIPL_COMP_ENTRY_LOAD) {
 435         zipl_load_segment(entry);
 436
 437         entry++;
 438
 439         IPL_assert((uint8_t *)(&entry[1]) <= (tmp_sec + MAX_SECTOR_SIZE),
 440                    "Wrong entry value");
 441     }
 442
 443     IPL_assert(entry->component_type == ZIPL_COMP_ENTRY_EXEC, "No EXEC entry");
 444
 445     /* should not return */
 446     jump_to_IPL_code(entry->load_address);
 447 }
 448
 449 static void ipl_scsi(void)
 450 {
 451     ScsiMbr *mbr = (void *)sec;
 452     uint8_t *ns, *ns_end;
 453     int program_table_entries = 0;
 454     const int pte_len = sizeof(ScsiBlockPtr);
 455     ScsiBlockPtr *prog_table_entry = NULL;
 456     unsigned int loadparm = get_loadparm_index();
 457
 458     /* Grab the MBR */
 459     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 460     read_block(0, mbr, "Cannot read block 0");
 461
 462     if (!magic_match(mbr->magic, ZIPL_MAGIC)) {
 463         return;
 464     }
 465
 466     sclp_print("Using SCSI scheme.\n");
 467     debug_print_int("MBR Version", mbr->version_id);
 468     IPL_check(mbr->version_id == 1,
 469               "Unknown MBR layout version, assuming version 1");
 470     debug_print_int("program table", mbr->blockptr[0].blockno);
 471     IPL_assert(mbr->blockptr[0].blockno, "No Program Table");
 472
 473     /* Parse the program table */
 474     read_block(mbr->blockptr[0].blockno, sec,
 475                "Error reading Program Table");
 476
 477     IPL_assert(magic_match(sec, ZIPL_MAGIC), "No zIPL magic in PT");
 478
 479     debug_print_int("loadparm index", loadparm);
 480     ns_end = sec + virtio_get_block_size();
 481     for (ns = (sec + pte_len); (ns + pte_len) < ns_end; ns += pte_len) {
 482         prog_table_entry = (ScsiBlockPtr *)ns;
 483         if (!prog_table_entry->blockno) {
 484             break;
 485         }
 486
 487         program_table_entries++;
 488         if (program_table_entries == loadparm + 1) {
 489             break; /* selected entry found */
 490         }
 491     }
 492
 493     debug_print_int("program table entries", program_table_entries);
 494
 495     IPL_assert(program_table_entries != 0, "Empty Program Table");
 496
 497     zipl_run(prog_table_entry); /* no return */
 498 }
 499
 500 /***********************************************************************
 501  * IPL El Torito ISO9660 image or DVD
 502  */
 503
 504 static bool is_iso_bc_entry_compatible(IsoBcSection *s)
 505 {
 506     uint8_t *magic_sec = (uint8_t *)(sec + ISO_SECTOR_SIZE);
 507
 508     if (s->unused || !s->sector_count) {
 509         return false;
 510     }
 511     read_iso_sector(bswap32(s->load_rba), magic_sec,
 512                     "Failed to read image sector 0");
 513
 514     /* Checking bytes 8 - 32 for S390 Linux magic */
 515     return !_memcmp(magic_sec + 8, linux_s390_magic, 24);
 516 }
 517
 518 /* Location of the current sector of the directory */
 519 static uint32_t sec_loc[ISO9660_MAX_DIR_DEPTH];
 520 /* Offset in the current sector of the directory */
 521 static uint32_t sec_offset[ISO9660_MAX_DIR_DEPTH];
 522 /* Remained directory space in bytes */
 523 static uint32_t dir_rem[ISO9660_MAX_DIR_DEPTH];
 524
 525 static inline uint32_t iso_get_file_size(uint32_t load_rba)
 526 {
 527     IsoVolDesc *vd = (IsoVolDesc *)sec;
 528     IsoDirHdr *cur_record = &vd->vd.primary.rootdir;
 529     uint8_t *temp = sec + ISO_SECTOR_SIZE;
 530     int level = 0;
 531
 532     read_iso_sector(ISO_PRIMARY_VD_SECTOR, sec,
 533                     "Failed to read ISO primary descriptor");
 534     sec_loc[0] = iso_733_to_u32(cur_record->ext_loc);
 535     dir_rem[0] = 0;
 536     sec_offset[0] = 0;
 537
 538     while (level >= 0) {
 539         IPL_assert(sec_offset[level] <= ISO_SECTOR_SIZE,
 540                    "Directory tree structure violation");
 541
 542         cur_record = (IsoDirHdr *)(temp + sec_offset[level]);
 543
 544         if (sec_offset[level] == 0) {
 545             read_iso_sector(sec_loc[level], temp,
 546                             "Failed to read ISO directory");
 547             if (dir_rem[level] == 0) {
 548                 /* Skip self and parent records */
 549                 dir_rem[level] = iso_733_to_u32(cur_record->data_len) -
 550                                  cur_record->dr_len;
 551                 sec_offset[level] += cur_record->dr_len;
 552
 553                 cur_record = (IsoDirHdr *)(temp + sec_offset[level]);
 554                 dir_rem[level] -= cur_record->dr_len;
 555                 sec_offset[level] += cur_record->dr_len;
 556                 continue;
 557             }
 558         }
 559
 560         if (!cur_record->dr_len || sec_offset[level] == ISO_SECTOR_SIZE) {
 561             /* Zero-padding and/or the end of current sector */
 562             dir_rem[level] -= ISO_SECTOR_SIZE - sec_offset[level];
 563             sec_offset[level] = 0;
 564             sec_loc[level]++;
 565         } else {
 566             /* The directory record is valid */
 567             if (load_rba == iso_733_to_u32(cur_record->ext_loc)) {
 568                 return iso_733_to_u32(cur_record->data_len);
 569             }
 570
 571             dir_rem[level] -= cur_record->dr_len;
 572             sec_offset[level] += cur_record->dr_len;
 573
 574             if (cur_record->file_flags & 0x2) {
 575                 /* Subdirectory */
 576                 if (level == ISO9660_MAX_DIR_DEPTH - 1) {
 577                     sclp_print("ISO-9660 directory depth limit exceeded\n");
 578                 } else {
 579                     level++;
 580                     sec_loc[level] = iso_733_to_u32(cur_record->ext_loc);
 581                     sec_offset[level] = 0;
 582                     dir_rem[level] = 0;
 583                     continue;
 584                 }
 585             }
 586         }
 587
 588         if (dir_rem[level] == 0) {
 589             /* Nothing remaining */
 590             level--;
 591             read_iso_sector(sec_loc[level], temp,
 592                             "Failed to read ISO directory");
 593         }
 594     }
 595
 596     return 0;
 597 }
 598
 599 static void load_iso_bc_entry(IsoBcSection *load)
 600 {
 601     IsoBcSection s = *load;
 602     /*
 603      * According to spec, extent for each file
 604      * is padded and ISO_SECTOR_SIZE bytes aligned
 605      */
 606     uint32_t blks_to_load = bswap16(s.sector_count) >> ET_SECTOR_SHIFT;
 607     uint32_t real_size = iso_get_file_size(bswap32(s.load_rba));
 608
 609     if (real_size) {
 610         /* Round up blocks to load */
 611         blks_to_load = (real_size + ISO_SECTOR_SIZE - 1) / ISO_SECTOR_SIZE;
 612         sclp_print("ISO boot image size verified\n");
 613     } else {
 614         sclp_print("ISO boot image size could not be verified\n");
 615     }
 616
 617     read_iso_boot_image(bswap32(s.load_rba),
 618                         (void *)((uint64_t)bswap16(s.load_segment)),
 619                         blks_to_load);
 620
 621     /* Trying to get PSW at zero address */
 622     if (*((uint64_t *)0) & IPL_PSW_MASK) {
 623         jump_to_IPL_code((*((uint64_t *)0)) & 0x7fffffff);
 624     }
 625
 626     /* Try default linux start address */
 627     jump_to_IPL_code(KERN_IMAGE_START);
 628 }
 629
 630 static uint32_t find_iso_bc(void)
 631 {
 632     IsoVolDesc *vd = (IsoVolDesc *)sec;
 633     uint32_t block_num = ISO_PRIMARY_VD_SECTOR;
 634
 635     if (virtio_read_many(block_num++, sec, 1)) {
 636         /* If primary vd cannot be read, there is no boot catalog */
 637         return 0;
 638     }
 639
 640     while (is_iso_vd_valid(vd) && vd->type != VOL_DESC_TERMINATOR) {
 641         if (vd->type == VOL_DESC_TYPE_BOOT) {
 642             IsoVdElTorito *et = &vd->vd.boot;
 643
 644             if (!_memcmp(&et->el_torito[0], el_torito_magic, 32)) {
 645                 return bswap32(et->bc_offset);
 646             }
 647         }
 648         read_iso_sector(block_num++, sec,
 649                         "Failed to read ISO volume descriptor");
 650     }
 651
 652     return 0;
 653 }
 654
 655 static IsoBcSection *find_iso_bc_entry(void)
 656 {
 657     IsoBcEntry *e = (IsoBcEntry *)sec;
 658     uint32_t offset = find_iso_bc();
 659     int i;
 660     unsigned int loadparm = get_loadparm_index();
 661
 662     if (!offset) {
 663         return NULL;
 664     }
 665
 666     read_iso_sector(offset, sec, "Failed to read El Torito boot catalog");
 667
 668     if (!is_iso_bc_valid(e)) {
 669         /* The validation entry is mandatory */
 670         panic("No valid boot catalog found!\n");
 671         return NULL;
 672     }
 673
 674     /*
 675      * Each entry has 32 bytes size, so one sector cannot contain > 64 entries.
 676      * We consider only boot catalogs with no more than 64 entries.
 677      */
 678     for (i = 1; i < ISO_BC_ENTRY_PER_SECTOR; i++) {
 679         if (e[i].id == ISO_BC_BOOTABLE_SECTION) {
 680             if (is_iso_bc_entry_compatible(&e[i].body.sect)) {
 681                 if (loadparm <= 1) {
 682                     /* found, default, or unspecified */
 683                     return &e[i].body.sect;
 684                 }
 685                 loadparm--;
 686             }
 687         }
 688     }
 689
 690     panic("No suitable boot entry found on ISO-9660 media!\n");
 691
 692     return NULL;
 693 }
 694
 695 static void ipl_iso_el_torito(void)
 696 {
 697     IsoBcSection *s = find_iso_bc_entry();
 698
 699     if (s) {
 700         load_iso_bc_entry(s);
 701         /* no return */
 702     }
 703 }
 704
 705 /***********************************************************************
 706  * Bus specific IPL sequences
 707  */
 708
 709 static void zipl_load_vblk(void)
 710 {
 711     if (virtio_guessed_disk_nature()) {
 712         virtio_assume_iso9660();
 713     }
 714     ipl_iso_el_torito();
 715
 716     if (virtio_guessed_disk_nature()) {
 717         sclp_print("Using guessed DASD geometry.\n");
 718         virtio_assume_eckd();
 719     }
 720     ipl_eckd();
 721 }
 722
 723 static void zipl_load_vscsi(void)
 724 {
 725     if (virtio_get_block_size() == VIRTIO_ISO_BLOCK_SIZE) {
 726         /* Is it an ISO image in non-CD drive? */
 727         ipl_iso_el_torito();
 728     }
 729
 730     sclp_print("Using guessed DASD geometry.\n");
 731     virtio_assume_eckd();
 732     ipl_eckd();
 733 }
 734
 735 /***********************************************************************
 736  * IPL starts here
 737  */
 738
 739 void zipl_load(void)
 740 {
 741     VDev *vdev = virtio_get_device();
 742
 743     if (vdev->is_cdrom) {
 744         ipl_iso_el_torito();
 745         panic("\n! Cannot IPL this ISO image !\n");
 746     }
 747
 748     if (virtio_get_device_type() == VIRTIO_ID_NET) {
 749         jump_to_IPL_code(vdev->netboot_start_addr);
 750     }
 751
 752     ipl_scsi();
 753
 754     switch (virtio_get_device_type()) {
 755     case VIRTIO_ID_BLOCK:
 756         zipl_load_vblk();
 757         break;
 758     case VIRTIO_ID_SCSI:
 759         zipl_load_vscsi();
 760         break;
 761     default:
 762         panic("\n! Unknown IPL device type !\n");
 763     }
 764
 765     panic("\n* this can never happen *\n");
 766 }