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 "s390-ccw.h"
  12 #include "bootmap.h"
  13 #include "virtio.h"
  14
  15 #ifdef DEBUG
  16 /* #define DEBUG_FALLBACK */
  17 #endif
  18
  19 #ifdef DEBUG_FALLBACK
  20 #define dputs(txt) \
  21     do { sclp_print("zipl: " txt); } while (0)
  22 #else
  23 #define dputs(fmt, ...) \
  24     do { } while (0)
  25 #endif
  26
  27 /* Scratch space */
  28 static uint8_t sec[MAX_SECTOR_SIZE*4] __attribute__((__aligned__(PAGE_SIZE)));
  29
  30 typedef struct ResetInfo {
  31     uint32_t ipl_mask;
  32     uint32_t ipl_addr;
  33     uint32_t ipl_continue;
  34 } ResetInfo;
  35
  36 ResetInfo save;
  37
  38 static void jump_to_IPL_2(void)
  39 {
  40     ResetInfo *current = 0;
  41
  42     void (*ipl)(void) = (void *) (uint64_t) current->ipl_continue;
  43     debug_print_addr("set IPL addr to", ipl);
  44
  45     /* Ensure the guest output starts fresh */
  46     sclp_print("\n");
  47
  48     *current = save;
  49     ipl(); /* should not return */
  50 }
  51
  52 static void jump_to_IPL_code(uint64_t address)
  53 {
  54     /* store the subsystem information _after_ the bootmap was loaded */
  55     write_subsystem_identification();
  56     /*
  57      * The IPL PSW is at address 0. We also must not overwrite the
  58      * content of non-BIOS memory after we loaded the guest, so we
  59      * save the original content and restore it in jump_to_IPL_2.
  60      */
  61     ResetInfo *current = 0;
  62
  63     save = *current;
  64     current->ipl_addr = (uint32_t) (uint64_t) &jump_to_IPL_2;
  65     current->ipl_continue = address & 0x7fffffff;
  66
  67     /*
  68      * HACK ALERT.
  69      * We use the load normal reset to keep r15 unchanged. jump_to_IPL_2
  70      * can then use r15 as its stack pointer.
  71      */
  72     asm volatile("lghi 1,1\n\t"
  73                  "diag 1,1,0x308\n\t"
  74                  : : : "1", "memory");
  75     virtio_panic("\n! IPL returns !\n");
  76 }
  77
  78 /***********************************************************************
  79  * IPL an ECKD DASD (CDL or LDL/CMS format)
  80  */
  81
  82 static unsigned char _bprs[8*1024]; /* guessed "max" ECKD sector size */
  83 const int max_bprs_entries = sizeof(_bprs) / sizeof(ExtEckdBlockPtr);
  84
  85 static inline void verify_boot_info(BootInfo *bip)
  86 {
  87     IPL_assert(magic_match(bip->magic, ZIPL_MAGIC), "No zIPL magic");
  88     IPL_assert(bip->version == BOOT_INFO_VERSION, "Wrong zIPL version");
  89     IPL_assert(bip->bp_type == BOOT_INFO_BP_TYPE_IPL, "DASD is not for IPL");
  90     IPL_assert(bip->dev_type == BOOT_INFO_DEV_TYPE_ECKD, "DASD is not ECKD");
  91     IPL_assert(bip->flags == BOOT_INFO_FLAGS_ARCH, "Not for this arch");
  92     IPL_assert(block_size_ok(bip->bp.ipl.bm_ptr.eckd.bptr.size),
  93                "Bad block size in zIPL section of the 1st record.");
  94 }
  95
  96 static bool eckd_valid_address(BootMapPointer *p)
  97 {
  98     const uint64_t cylinder = p->eckd.cylinder
  99                             + ((p->eckd.head & 0xfff0) << 12);
 100     const uint64_t head = p->eckd.head & 0x000f;
 101
 102     if (head >= virtio_get_heads()
 103         ||  p->eckd.sector > virtio_get_sectors()
 104         ||  p->eckd.sector <= 0) {
 105         return false;
 106     }
 107
 108     if (!virtio_guessed_disk_nature() && cylinder >= virtio_get_cylinders()) {
 109         return false;
 110     }
 111
 112     return true;
 113 }
 114
 115 static block_number_t eckd_block_num(BootMapPointer *p)
 116 {
 117     const uint64_t sectors = virtio_get_sectors();
 118     const uint64_t heads = virtio_get_heads();
 119     const uint64_t cylinder = p->eckd.cylinder
 120                             + ((p->eckd.head & 0xfff0) << 12);
 121     const uint64_t head = p->eckd.head & 0x000f;
 122     const block_number_t block = sectors * heads * cylinder
 123                                + sectors * head
 124                                + p->eckd.sector
 125                                - 1; /* block nr starts with zero */
 126     return block;
 127 }
 128
 129 static block_number_t load_eckd_segments(block_number_t blk, uint64_t *address)
 130 {
 131     block_number_t block_nr;
 132     int j, rc;
 133     BootMapPointer *bprs = (void *)_bprs;
 134     bool more_data;
 135
 136     memset(_bprs, FREE_SPACE_FILLER, sizeof(_bprs));
 137     read_block(blk, bprs, "BPRS read failed");
 138
 139     do {
 140         more_data = false;
 141         for (j = 0;; j++) {
 142             block_nr = eckd_block_num((void *)&(bprs[j].xeckd));
 143             if (is_null_block_number(block_nr)) { /* end of chunk */
 144                 break;
 145             }
 146
 147             /* we need the updated blockno for the next indirect entry
 148              * in the chain, but don't want to advance address
 149              */
 150             if (j == (max_bprs_entries - 1)) {
 151                 break;
 152             }
 153
 154             IPL_assert(block_size_ok(bprs[j].xeckd.bptr.size),
 155                        "bad chunk block size");
 156             IPL_assert(eckd_valid_address(&bprs[j]), "bad chunk ECKD addr");
 157
 158             if ((bprs[j].xeckd.bptr.count == 0) && unused_space(&(bprs[j+1]),
 159                 sizeof(EckdBlockPtr))) {
 160                 /* This is a "continue" pointer.
 161                  * This ptr should be the last one in the current
 162                  * script section.
 163                  * I.e. the next ptr must point to the unused memory area
 164                  */
 165                 memset(_bprs, FREE_SPACE_FILLER, sizeof(_bprs));
 166                 read_block(block_nr, bprs, "BPRS continuation read failed");
 167                 more_data = true;
 168                 break;
 169             }
 170
 171             /* Load (count+1) blocks of code at (block_nr)
 172              * to memory (address).
 173              */
 174             rc = virtio_read_many(block_nr, (void *)(*address),
 175                                   bprs[j].xeckd.bptr.count+1);
 176             IPL_assert(rc == 0, "code chunk read failed");
 177
 178             *address += (bprs[j].xeckd.bptr.count+1) * virtio_get_block_size();
 179         }
 180     } while (more_data);
 181     return block_nr;
 182 }
 183
 184 static void run_eckd_boot_script(block_number_t mbr_block_nr)
 185 {
 186     int i;
 187     block_number_t block_nr;
 188     uint64_t address;
 189     ScsiMbr *scsi_mbr = (void *)sec;
 190     BootMapScript *bms = (void *)sec;
 191
 192     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 193     read_block(mbr_block_nr, sec, "Cannot read MBR");
 194
 195     block_nr = eckd_block_num((void *)&(scsi_mbr->blockptr));
 196
 197     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 198     read_block(block_nr, sec, "Cannot read Boot Map Script");
 199
 200     for (i = 0; bms->entry[i].type == BOOT_SCRIPT_LOAD; i++) {
 201         address = bms->entry[i].address.load_address;
 202         block_nr = eckd_block_num(&(bms->entry[i].blkptr));
 203
 204         do {
 205             block_nr = load_eckd_segments(block_nr, &address);
 206         } while (block_nr != -1);
 207     }
 208
 209     IPL_assert(bms->entry[i].type == BOOT_SCRIPT_EXEC,
 210                "Unknown script entry type");
 211     jump_to_IPL_code(bms->entry[i].address.load_address); /* no return */
 212 }
 213
 214 static void ipl_eckd_cdl(void)
 215 {
 216     XEckdMbr *mbr;
 217     Ipl2 *ipl2 = (void *)sec;
 218     IplVolumeLabel *vlbl = (void *)sec;
 219     block_number_t block_nr;
 220
 221     /* we have just read the block #0 and recognized it as "IPL1" */
 222     sclp_print("CDL\n");
 223
 224     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 225     read_block(1, ipl2, "Cannot read IPL2 record at block 1");
 226     IPL_assert(magic_match(ipl2, IPL2_MAGIC), "No IPL2 record");
 227
 228     mbr = &ipl2->u.x.mbr;
 229     IPL_assert(magic_match(mbr, ZIPL_MAGIC), "No zIPL section in IPL2 record.");
 230     IPL_assert(block_size_ok(mbr->blockptr.xeckd.bptr.size),
 231                "Bad block size in zIPL section of IPL2 record.");
 232     IPL_assert(mbr->dev_type == DEV_TYPE_ECKD,
 233                "Non-ECKD device type in zIPL section of IPL2 record.");
 234
 235     /* save pointer to Boot Script */
 236     block_nr = eckd_block_num((void *)&(mbr->blockptr));
 237
 238     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 239     read_block(2, vlbl, "Cannot read Volume Label at block 2");
 240     IPL_assert(magic_match(vlbl->key, VOL1_MAGIC),
 241                "Invalid magic of volume label block");
 242     IPL_assert(magic_match(vlbl->f.key, VOL1_MAGIC),
 243                "Invalid magic of volser block");
 244     print_volser(vlbl->f.volser);
 245
 246     run_eckd_boot_script(block_nr);
 247     /* no return */
 248 }
 249
 250 static void ipl_eckd_ldl(ECKD_IPL_mode_t mode)
 251 {
 252     LDL_VTOC *vlbl = (void *)sec; /* already read, 3rd block */
 253     char msg[4] = { '?', '.', '\n', '\0' };
 254     block_number_t block_nr;
 255     BootInfo *bip;
 256
 257     sclp_print((mode == ECKD_CMS) ? "CMS" : "LDL");
 258     sclp_print(" version ");
 259     switch (vlbl->LDL_version) {
 260     case LDL1_VERSION:
 261         msg[0] = '1';
 262         break;
 263     case LDL2_VERSION:
 264         msg[0] = '2';
 265         break;
 266     default:
 267         msg[0] = vlbl->LDL_version;
 268         msg[0] &= 0x0f; /* convert EBCDIC   */
 269         msg[0] |= 0x30; /* to ASCII (digit) */
 270         msg[1] = '?';
 271         break;
 272     }
 273     sclp_print(msg);
 274     print_volser(vlbl->volser);
 275
 276     /* DO NOT read BootMap pointer (only one, xECKD) at block #2 */
 277
 278     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 279     read_block(0, sec, "Cannot read block 0");
 280     bip = (void *)(sec + 0x70); /* "boot info" is "eckd mbr" for LDL */
 281     verify_boot_info(bip);
 282
 283     block_nr = eckd_block_num((void *)&(bip->bp.ipl.bm_ptr.eckd.bptr));
 284     run_eckd_boot_script(block_nr);
 285     /* no return */
 286 }
 287
 288 static void ipl_eckd(ECKD_IPL_mode_t mode)
 289 {
 290     switch (mode) {
 291     case ECKD_CDL:
 292         ipl_eckd_cdl(); /* no return */
 293     case ECKD_CMS:
 294     case ECKD_LDL:
 295         ipl_eckd_ldl(mode); /* no return */
 296     default:
 297         virtio_panic("\n! Unknown ECKD IPL mode !\n");
 298     }
 299 }
 300
 301 /***********************************************************************
 302  * IPL a SCSI disk
 303  */
 304
 305 static void zipl_load_segment(ComponentEntry *entry)
 306 {
 307     const int max_entries = (MAX_SECTOR_SIZE / sizeof(ScsiBlockPtr));
 308     ScsiBlockPtr *bprs = (void *)sec;
 309     const int bprs_size = sizeof(sec);
 310     block_number_t blockno;
 311     uint64_t address;
 312     int i;
 313     char err_msg[] = "zIPL failed to read BPRS at 0xZZZZZZZZZZZZZZZZ";
 314     char *blk_no = &err_msg[30]; /* where to print blockno in (those ZZs) */
 315
 316     blockno = entry->data.blockno;
 317     address = entry->load_address;
 318
 319     debug_print_int("loading segment at block", blockno);
 320     debug_print_int("addr", address);
 321
 322     do {
 323         memset(bprs, FREE_SPACE_FILLER, bprs_size);
 324         fill_hex_val(blk_no, &blockno, sizeof(blockno));
 325         read_block(blockno, bprs, err_msg);
 326
 327         for (i = 0;; i++) {
 328             uint64_t *cur_desc = (void *)&bprs[i];
 329
 330             blockno = bprs[i].blockno;
 331             if (!blockno) {
 332                 break;
 333             }
 334
 335             /* we need the updated blockno for the next indirect entry in the
 336                chain, but don't want to advance address */
 337             if (i == (max_entries - 1)) {
 338                 break;
 339             }
 340
 341             if (bprs[i].blockct == 0 && unused_space(&bprs[i + 1],
 342                 sizeof(ScsiBlockPtr))) {
 343                 /* This is a "continue" pointer.
 344                  * This ptr is the last one in the current script section.
 345                  * I.e. the next ptr must point to the unused memory area.
 346                  * The blockno is not zero, so the upper loop must continue
 347                  * reading next section of BPRS.
 348                  */
 349                 break;
 350             }
 351             address = virtio_load_direct(cur_desc[0], cur_desc[1], 0,
 352                                          (void *)address);
 353             IPL_assert(address != -1, "zIPL load segment failed");
 354         }
 355     } while (blockno);
 356 }
 357
 358 /* Run a zipl program */
 359 static void zipl_run(ScsiBlockPtr *pte)
 360 {
 361     ComponentHeader *header;
 362     ComponentEntry *entry;
 363     uint8_t tmp_sec[MAX_SECTOR_SIZE];
 364
 365     read_block(pte->blockno, tmp_sec, "Cannot read header");
 366     header = (ComponentHeader *)tmp_sec;
 367
 368     IPL_assert(magic_match(tmp_sec, ZIPL_MAGIC), "No zIPL magic");
 369     IPL_assert(header->type == ZIPL_COMP_HEADER_IPL, "Bad header type");
 370
 371     dputs("start loading images\n");
 372
 373     /* Load image(s) into RAM */
 374     entry = (ComponentEntry *)(&header[1]);
 375     while (entry->component_type == ZIPL_COMP_ENTRY_LOAD) {
 376         zipl_load_segment(entry);
 377
 378         entry++;
 379
 380         IPL_assert((uint8_t *)(&entry[1]) <= (tmp_sec + MAX_SECTOR_SIZE),
 381                    "Wrong entry value");
 382     }
 383
 384     IPL_assert(entry->component_type == ZIPL_COMP_ENTRY_EXEC, "No EXEC entry");
 385
 386     /* should not return */
 387     jump_to_IPL_code(entry->load_address);
 388 }
 389
 390 static void ipl_scsi(void)
 391 {
 392     ScsiMbr *mbr = (void *)sec;
 393     uint8_t *ns, *ns_end;
 394     int program_table_entries = 0;
 395     const int pte_len = sizeof(ScsiBlockPtr);
 396     ScsiBlockPtr *prog_table_entry;
 397
 398     /* The 0-th block (MBR) was already read into sec[] */
 399
 400     sclp_print("Using SCSI scheme.\n");
 401     debug_print_int("program table", mbr->blockptr.blockno);
 402
 403     /* Parse the program table */
 404     read_block(mbr->blockptr.blockno, sec,
 405                "Error reading Program Table");
 406
 407     IPL_assert(magic_match(sec, ZIPL_MAGIC), "No zIPL magic");
 408
 409     ns_end = sec + virtio_get_block_size();
 410     for (ns = (sec + pte_len); (ns + pte_len) < ns_end; ns++) {
 411         prog_table_entry = (ScsiBlockPtr *)ns;
 412         if (!prog_table_entry->blockno) {
 413             break;
 414         }
 415
 416         program_table_entries++;
 417     }
 418
 419     debug_print_int("program table entries", program_table_entries);
 420
 421     IPL_assert(program_table_entries != 0, "Empty Program Table");
 422
 423     /* Run the default entry */
 424
 425     prog_table_entry = (ScsiBlockPtr *)(sec + pte_len);
 426
 427     zipl_run(prog_table_entry); /* no return */
 428 }
 429
 430 /***********************************************************************
 431  * IPL starts here
 432  */
 433
 434 void zipl_load(void)
 435 {
 436     ScsiMbr *mbr = (void *)sec;
 437     LDL_VTOC *vlbl = (void *)sec;
 438
 439     /* Grab the MBR */
 440     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 441     read_block(0, mbr, "Cannot read block 0");
 442
 443     dputs("checking magic\n");
 444
 445     if (magic_match(mbr->magic, ZIPL_MAGIC)) {
 446         ipl_scsi(); /* no return */
 447     }
 448
 449     /* We have failed to follow the SCSI scheme, so */
 450     sclp_print("Using ECKD scheme.\n");
 451     if (virtio_guessed_disk_nature()) {
 452         sclp_print("Using guessed DASD geometry.\n");
 453         virtio_assume_eckd();
 454     }
 455
 456     if (magic_match(mbr->magic, IPL1_MAGIC)) {
 457         ipl_eckd(ECKD_CDL); /* no return */
 458     }
 459
 460     /* LDL/CMS? */
 461     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
 462     read_block(2, vlbl, "Cannot read block 2");
 463
 464     if (magic_match(vlbl->magic, CMS1_MAGIC)) {
 465         ipl_eckd(ECKD_CMS); /* no return */
 466     }
 467     if (magic_match(vlbl->magic, LNX1_MAGIC)) {
 468         ipl_eckd(ECKD_LDL); /* no return */
 469     }
 470
 471     virtio_panic("\n* invalid MBR magic *\n");
 472 }