xref: /openbmc/qemu/pc-bios/s390-ccw/bootmap.c (revision 6598f0cd)
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 const uint8_t el_torito_magic[] = "EL TORITO SPECIFICATION"
33                                   "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
34 
35 /*
36  * Match two CCWs located after PSW and eight filler bytes.
37  * From libmagic and arch/s390/kernel/head.S.
38  */
39 const uint8_t linux_s390_magic[] = "\x02\x00\x00\x18\x60\x00\x00\x50\x02\x00"
40                                    "\x00\x68\x60\x00\x00\x50\x40\x40\x40\x40"
41                                    "\x40\x40\x40\x40";
42 
43 static inline bool is_iso_vd_valid(IsoVolDesc *vd)
44 {
45     const uint8_t vol_desc_magic[] = "CD001";
46 
47     return !memcmp(&vd->ident[0], vol_desc_magic, 5) &&
48            vd->version == 0x1 &&
49            vd->type <= VOL_DESC_TYPE_PARTITION;
50 }
51 
52 /***********************************************************************
53  * IPL an ECKD DASD (CDL or LDL/CMS format)
54  */
55 
56 static unsigned char _bprs[8*1024]; /* guessed "max" ECKD sector size */
57 static const int max_bprs_entries = sizeof(_bprs) / sizeof(ExtEckdBlockPtr);
58 static uint8_t _s2[MAX_SECTOR_SIZE * 3] __attribute__((__aligned__(PAGE_SIZE)));
59 static void *s2_prev_blk = _s2;
60 static void *s2_cur_blk = _s2 + MAX_SECTOR_SIZE;
61 static void *s2_next_blk = _s2 + MAX_SECTOR_SIZE * 2;
62 
63 static inline void verify_boot_info(BootInfo *bip)
64 {
65     IPL_assert(magic_match(bip->magic, ZIPL_MAGIC), "No zIPL sig in BootInfo");
66     IPL_assert(bip->version == BOOT_INFO_VERSION, "Wrong zIPL version");
67     IPL_assert(bip->bp_type == BOOT_INFO_BP_TYPE_IPL, "DASD is not for IPL");
68     IPL_assert(bip->dev_type == BOOT_INFO_DEV_TYPE_ECKD, "DASD is not ECKD");
69     IPL_assert(bip->flags == BOOT_INFO_FLAGS_ARCH, "Not for this arch");
70     IPL_assert(block_size_ok(bip->bp.ipl.bm_ptr.eckd.bptr.size),
71                "Bad block size in zIPL section of the 1st record.");
72 }
73 
74 static block_number_t eckd_block_num(EckdCHS *chs)
75 {
76     const uint64_t sectors = virtio_get_sectors();
77     const uint64_t heads = virtio_get_heads();
78     const uint64_t cylinder = chs->cylinder
79                             + ((chs->head & 0xfff0) << 12);
80     const uint64_t head = chs->head & 0x000f;
81     const block_number_t block = sectors * heads * cylinder
82                                + sectors * head
83                                + chs->sector
84                                - 1; /* block nr starts with zero */
85     return block;
86 }
87 
88 static bool eckd_valid_address(BootMapPointer *p)
89 {
90     const uint64_t head = p->eckd.chs.head & 0x000f;
91 
92     if (head >= virtio_get_heads()
93         ||  p->eckd.chs.sector > virtio_get_sectors()
94         ||  p->eckd.chs.sector <= 0) {
95         return false;
96     }
97 
98     if (!virtio_guessed_disk_nature() &&
99         eckd_block_num(&p->eckd.chs) >= virtio_get_blocks()) {
100         return false;
101     }
102 
103     return true;
104 }
105 
106 static block_number_t load_eckd_segments(block_number_t blk, uint64_t *address)
107 {
108     block_number_t block_nr;
109     int j, rc;
110     BootMapPointer *bprs = (void *)_bprs;
111     bool more_data;
112 
113     memset(_bprs, FREE_SPACE_FILLER, sizeof(_bprs));
114     read_block(blk, bprs, "BPRS read failed");
115 
116     do {
117         more_data = false;
118         for (j = 0;; j++) {
119             block_nr = eckd_block_num(&bprs[j].xeckd.bptr.chs);
120             if (is_null_block_number(block_nr)) { /* end of chunk */
121                 break;
122             }
123 
124             /* we need the updated blockno for the next indirect entry
125              * in the chain, but don't want to advance address
126              */
127             if (j == (max_bprs_entries - 1)) {
128                 break;
129             }
130 
131             IPL_assert(block_size_ok(bprs[j].xeckd.bptr.size),
132                        "bad chunk block size");
133             IPL_assert(eckd_valid_address(&bprs[j]), "bad chunk ECKD addr");
134 
135             if ((bprs[j].xeckd.bptr.count == 0) && unused_space(&(bprs[j+1]),
136                 sizeof(EckdBlockPtr))) {
137                 /* This is a "continue" pointer.
138                  * This ptr should be the last one in the current
139                  * script section.
140                  * I.e. the next ptr must point to the unused memory area
141                  */
142                 memset(_bprs, FREE_SPACE_FILLER, sizeof(_bprs));
143                 read_block(block_nr, bprs, "BPRS continuation read failed");
144                 more_data = true;
145                 break;
146             }
147 
148             /* Load (count+1) blocks of code at (block_nr)
149              * to memory (address).
150              */
151             rc = virtio_read_many(block_nr, (void *)(*address),
152                                   bprs[j].xeckd.bptr.count+1);
153             IPL_assert(rc == 0, "code chunk read failed");
154 
155             *address += (bprs[j].xeckd.bptr.count+1) * virtio_get_block_size();
156         }
157     } while (more_data);
158     return block_nr;
159 }
160 
161 static bool find_zipl_boot_menu_banner(int *offset)
162 {
163     int i;
164 
165     /* Menu banner starts with "zIPL" */
166     for (i = 0; i < virtio_get_block_size() - 4; i++) {
167         if (magic_match(s2_cur_blk + i, ZIPL_MAGIC_EBCDIC)) {
168             *offset = i;
169             return true;
170         }
171     }
172 
173     return false;
174 }
175 
176 static int eckd_get_boot_menu_index(block_number_t s1b_block_nr)
177 {
178     block_number_t cur_block_nr;
179     block_number_t prev_block_nr = 0;
180     block_number_t next_block_nr = 0;
181     EckdStage1b *s1b = (void *)sec;
182     int banner_offset;
183     int i;
184 
185     /* Get Stage1b data */
186     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
187     read_block(s1b_block_nr, s1b, "Cannot read stage1b boot loader");
188 
189     memset(_s2, FREE_SPACE_FILLER, sizeof(_s2));
190 
191     /* Get Stage2 data */
192     for (i = 0; i < STAGE2_BLK_CNT_MAX; i++) {
193         cur_block_nr = eckd_block_num(&s1b->seek[i].chs);
194 
195         if (!cur_block_nr) {
196             break;
197         }
198 
199         read_block(cur_block_nr, s2_cur_blk, "Cannot read stage2 boot loader");
200 
201         if (find_zipl_boot_menu_banner(&banner_offset)) {
202             /*
203              * Load the adjacent blocks to account for the
204              * possibility of menu data spanning multiple blocks.
205              */
206             if (prev_block_nr) {
207                 read_block(prev_block_nr, s2_prev_blk,
208                            "Cannot read stage2 boot loader");
209             }
210 
211             if (i + 1 < STAGE2_BLK_CNT_MAX) {
212                 next_block_nr = eckd_block_num(&s1b->seek[i + 1].chs);
213             }
214 
215             if (next_block_nr) {
216                 read_block(next_block_nr, s2_next_blk,
217                            "Cannot read stage2 boot loader");
218             }
219 
220             return menu_get_zipl_boot_index(s2_cur_blk + banner_offset);
221         }
222 
223         prev_block_nr = cur_block_nr;
224     }
225 
226     sclp_print("No zipl boot menu data found. Booting default entry.");
227     return 0;
228 }
229 
230 static void run_eckd_boot_script(block_number_t bmt_block_nr,
231                                  block_number_t s1b_block_nr)
232 {
233     int i;
234     unsigned int loadparm = get_loadparm_index();
235     block_number_t block_nr;
236     uint64_t address;
237     BootMapTable *bmt = (void *)sec;
238     BootMapScript *bms = (void *)sec;
239 
240     if (menu_is_enabled_zipl()) {
241         loadparm = eckd_get_boot_menu_index(s1b_block_nr);
242     }
243 
244     debug_print_int("loadparm", loadparm);
245     IPL_assert(loadparm < MAX_BOOT_ENTRIES, "loadparm value greater than"
246                " maximum number of boot entries allowed");
247 
248     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
249     read_block(bmt_block_nr, sec, "Cannot read Boot Map Table");
250 
251     block_nr = eckd_block_num(&bmt->entry[loadparm].xeckd.bptr.chs);
252     IPL_assert(block_nr != -1, "Cannot find Boot Map Table Entry");
253 
254     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
255     read_block(block_nr, sec, "Cannot read Boot Map Script");
256 
257     for (i = 0; bms->entry[i].type == BOOT_SCRIPT_LOAD; i++) {
258         address = bms->entry[i].address.load_address;
259         block_nr = eckd_block_num(&bms->entry[i].blkptr.xeckd.bptr.chs);
260 
261         do {
262             block_nr = load_eckd_segments(block_nr, &address);
263         } while (block_nr != -1);
264     }
265 
266     IPL_assert(bms->entry[i].type == BOOT_SCRIPT_EXEC,
267                "Unknown script entry type");
268     jump_to_IPL_code(bms->entry[i].address.load_address); /* no return */
269 }
270 
271 static void ipl_eckd_cdl(void)
272 {
273     XEckdMbr *mbr;
274     EckdCdlIpl2 *ipl2 = (void *)sec;
275     IplVolumeLabel *vlbl = (void *)sec;
276     block_number_t bmt_block_nr, s1b_block_nr;
277 
278     /* we have just read the block #0 and recognized it as "IPL1" */
279     sclp_print("CDL\n");
280 
281     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
282     read_block(1, ipl2, "Cannot read IPL2 record at block 1");
283 
284     mbr = &ipl2->mbr;
285     IPL_assert(magic_match(mbr, ZIPL_MAGIC), "No zIPL section in IPL2 record.");
286     IPL_assert(block_size_ok(mbr->blockptr.xeckd.bptr.size),
287                "Bad block size in zIPL section of IPL2 record.");
288     IPL_assert(mbr->dev_type == DEV_TYPE_ECKD,
289                "Non-ECKD device type in zIPL section of IPL2 record.");
290 
291     /* save pointer to Boot Map Table */
292     bmt_block_nr = eckd_block_num(&mbr->blockptr.xeckd.bptr.chs);
293 
294     /* save pointer to Stage1b Data */
295     s1b_block_nr = eckd_block_num(&ipl2->stage1.seek[0].chs);
296 
297     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
298     read_block(2, vlbl, "Cannot read Volume Label at block 2");
299     IPL_assert(magic_match(vlbl->key, VOL1_MAGIC),
300                "Invalid magic of volume label block");
301     IPL_assert(magic_match(vlbl->f.key, VOL1_MAGIC),
302                "Invalid magic of volser block");
303     print_volser(vlbl->f.volser);
304 
305     run_eckd_boot_script(bmt_block_nr, s1b_block_nr);
306     /* no return */
307 }
308 
309 static void print_eckd_ldl_msg(ECKD_IPL_mode_t mode)
310 {
311     LDL_VTOC *vlbl = (void *)sec; /* already read, 3rd block */
312     char msg[4] = { '?', '.', '\n', '\0' };
313 
314     sclp_print((mode == ECKD_CMS) ? "CMS" : "LDL");
315     sclp_print(" version ");
316     switch (vlbl->LDL_version) {
317     case LDL1_VERSION:
318         msg[0] = '1';
319         break;
320     case LDL2_VERSION:
321         msg[0] = '2';
322         break;
323     default:
324         msg[0] = vlbl->LDL_version;
325         msg[0] &= 0x0f; /* convert EBCDIC   */
326         msg[0] |= 0x30; /* to ASCII (digit) */
327         msg[1] = '?';
328         break;
329     }
330     sclp_print(msg);
331     print_volser(vlbl->volser);
332 }
333 
334 static void ipl_eckd_ldl(ECKD_IPL_mode_t mode)
335 {
336     block_number_t bmt_block_nr, s1b_block_nr;
337     EckdLdlIpl1 *ipl1 = (void *)sec;
338 
339     if (mode != ECKD_LDL_UNLABELED) {
340         print_eckd_ldl_msg(mode);
341     }
342 
343     /* DO NOT read BootMap pointer (only one, xECKD) at block #2 */
344 
345     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
346     read_block(0, sec, "Cannot read block 0 to grab boot info.");
347     if (mode == ECKD_LDL_UNLABELED) {
348         if (!magic_match(ipl1->bip.magic, ZIPL_MAGIC)) {
349             return; /* not applicable layout */
350         }
351         sclp_print("unlabeled LDL.\n");
352     }
353     verify_boot_info(&ipl1->bip);
354 
355     /* save pointer to Boot Map Table */
356     bmt_block_nr = eckd_block_num(&ipl1->bip.bp.ipl.bm_ptr.eckd.bptr.chs);
357 
358     /* save pointer to Stage1b Data */
359     s1b_block_nr = eckd_block_num(&ipl1->stage1.seek[0].chs);
360 
361     run_eckd_boot_script(bmt_block_nr, s1b_block_nr);
362     /* no return */
363 }
364 
365 static void print_eckd_msg(void)
366 {
367     char msg[] = "Using ECKD scheme (block size *****), ";
368     char *p = &msg[34], *q = &msg[30];
369     int n = virtio_get_block_size();
370 
371     /* Fill in the block size and show up the message */
372     if (n > 0 && n <= 99999) {
373         while (n) {
374             *p-- = '0' + (n % 10);
375             n /= 10;
376         }
377         while (p >= q) {
378             *p-- = ' ';
379         }
380     }
381     sclp_print(msg);
382 }
383 
384 static void ipl_eckd(void)
385 {
386     XEckdMbr *mbr = (void *)sec;
387     LDL_VTOC *vlbl = (void *)sec;
388 
389     print_eckd_msg();
390 
391     /* Grab the MBR again */
392     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
393     read_block(0, mbr, "Cannot read block 0 on DASD");
394 
395     if (magic_match(mbr->magic, IPL1_MAGIC)) {
396         ipl_eckd_cdl(); /* no return */
397     }
398 
399     /* LDL/CMS? */
400     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
401     read_block(2, vlbl, "Cannot read block 2");
402 
403     if (magic_match(vlbl->magic, CMS1_MAGIC)) {
404         ipl_eckd_ldl(ECKD_CMS); /* no return */
405     }
406     if (magic_match(vlbl->magic, LNX1_MAGIC)) {
407         ipl_eckd_ldl(ECKD_LDL); /* no return */
408     }
409 
410     ipl_eckd_ldl(ECKD_LDL_UNLABELED); /* it still may return */
411     /*
412      * Ok, it is not a LDL by any means.
413      * It still might be a CDL with zero record keys for IPL1 and IPL2
414      */
415     ipl_eckd_cdl();
416 }
417 
418 /***********************************************************************
419  * IPL a SCSI disk
420  */
421 
422 static void zipl_load_segment(ComponentEntry *entry)
423 {
424     const int max_entries = (MAX_SECTOR_SIZE / sizeof(ScsiBlockPtr));
425     ScsiBlockPtr *bprs = (void *)sec;
426     const int bprs_size = sizeof(sec);
427     block_number_t blockno;
428     uint64_t address;
429     int i;
430     char err_msg[] = "zIPL failed to read BPRS at 0xZZZZZZZZZZZZZZZZ";
431     char *blk_no = &err_msg[30]; /* where to print blockno in (those ZZs) */
432 
433     blockno = entry->data.blockno;
434     address = entry->load_address;
435 
436     debug_print_int("loading segment at block", blockno);
437     debug_print_int("addr", address);
438 
439     do {
440         memset(bprs, FREE_SPACE_FILLER, bprs_size);
441         fill_hex_val(blk_no, &blockno, sizeof(blockno));
442         read_block(blockno, bprs, err_msg);
443 
444         for (i = 0;; i++) {
445             uint64_t *cur_desc = (void *)&bprs[i];
446 
447             blockno = bprs[i].blockno;
448             if (!blockno) {
449                 break;
450             }
451 
452             /* we need the updated blockno for the next indirect entry in the
453                chain, but don't want to advance address */
454             if (i == (max_entries - 1)) {
455                 break;
456             }
457 
458             if (bprs[i].blockct == 0 && unused_space(&bprs[i + 1],
459                 sizeof(ScsiBlockPtr))) {
460                 /* This is a "continue" pointer.
461                  * This ptr is the last one in the current script section.
462                  * I.e. the next ptr must point to the unused memory area.
463                  * The blockno is not zero, so the upper loop must continue
464                  * reading next section of BPRS.
465                  */
466                 break;
467             }
468             address = virtio_load_direct(cur_desc[0], cur_desc[1], 0,
469                                          (void *)address);
470             IPL_assert(address != -1, "zIPL load segment failed");
471         }
472     } while (blockno);
473 }
474 
475 /* Run a zipl program */
476 static void zipl_run(ScsiBlockPtr *pte)
477 {
478     ComponentHeader *header;
479     ComponentEntry *entry;
480     uint8_t tmp_sec[MAX_SECTOR_SIZE];
481 
482     read_block(pte->blockno, tmp_sec, "Cannot read header");
483     header = (ComponentHeader *)tmp_sec;
484 
485     IPL_assert(magic_match(tmp_sec, ZIPL_MAGIC), "No zIPL magic in header");
486     IPL_assert(header->type == ZIPL_COMP_HEADER_IPL, "Bad header type");
487 
488     dputs("start loading images\n");
489 
490     /* Load image(s) into RAM */
491     entry = (ComponentEntry *)(&header[1]);
492     while (entry->component_type == ZIPL_COMP_ENTRY_LOAD) {
493         zipl_load_segment(entry);
494 
495         entry++;
496 
497         IPL_assert((uint8_t *)(&entry[1]) <= (tmp_sec + MAX_SECTOR_SIZE),
498                    "Wrong entry value");
499     }
500 
501     IPL_assert(entry->component_type == ZIPL_COMP_ENTRY_EXEC, "No EXEC entry");
502 
503     /* should not return */
504     jump_to_IPL_code(entry->load_address);
505 }
506 
507 static void ipl_scsi(void)
508 {
509     ScsiMbr *mbr = (void *)sec;
510     int program_table_entries = 0;
511     BootMapTable *prog_table = (void *)sec;
512     unsigned int loadparm = get_loadparm_index();
513     bool valid_entries[MAX_BOOT_ENTRIES] = {false};
514     size_t i;
515 
516     /* Grab the MBR */
517     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
518     read_block(0, mbr, "Cannot read block 0");
519 
520     if (!magic_match(mbr->magic, ZIPL_MAGIC)) {
521         return;
522     }
523 
524     sclp_print("Using SCSI scheme.\n");
525     debug_print_int("MBR Version", mbr->version_id);
526     IPL_check(mbr->version_id == 1,
527               "Unknown MBR layout version, assuming version 1");
528     debug_print_int("program table", mbr->pt.blockno);
529     IPL_assert(mbr->pt.blockno, "No Program Table");
530 
531     /* Parse the program table */
532     read_block(mbr->pt.blockno, sec, "Error reading Program Table");
533     IPL_assert(magic_match(sec, ZIPL_MAGIC), "No zIPL magic in PT");
534 
535     for (i = 0; i < MAX_BOOT_ENTRIES; i++) {
536         if (prog_table->entry[i].scsi.blockno) {
537             valid_entries[i] = true;
538             program_table_entries++;
539         }
540     }
541 
542     debug_print_int("program table entries", program_table_entries);
543     IPL_assert(program_table_entries != 0, "Empty Program Table");
544 
545     if (menu_is_enabled_enum()) {
546         loadparm = menu_get_enum_boot_index(valid_entries);
547     }
548 
549     debug_print_int("loadparm", loadparm);
550     IPL_assert(loadparm < MAX_BOOT_ENTRIES, "loadparm value greater than"
551                " maximum number of boot entries allowed");
552 
553     zipl_run(&prog_table->entry[loadparm].scsi); /* no return */
554 }
555 
556 /***********************************************************************
557  * IPL El Torito ISO9660 image or DVD
558  */
559 
560 static bool is_iso_bc_entry_compatible(IsoBcSection *s)
561 {
562     uint8_t *magic_sec = (uint8_t *)(sec + ISO_SECTOR_SIZE);
563 
564     if (s->unused || !s->sector_count) {
565         return false;
566     }
567     read_iso_sector(bswap32(s->load_rba), magic_sec,
568                     "Failed to read image sector 0");
569 
570     /* Checking bytes 8 - 32 for S390 Linux magic */
571     return !memcmp(magic_sec + 8, linux_s390_magic, 24);
572 }
573 
574 /* Location of the current sector of the directory */
575 static uint32_t sec_loc[ISO9660_MAX_DIR_DEPTH];
576 /* Offset in the current sector of the directory */
577 static uint32_t sec_offset[ISO9660_MAX_DIR_DEPTH];
578 /* Remained directory space in bytes */
579 static uint32_t dir_rem[ISO9660_MAX_DIR_DEPTH];
580 
581 static inline uint32_t iso_get_file_size(uint32_t load_rba)
582 {
583     IsoVolDesc *vd = (IsoVolDesc *)sec;
584     IsoDirHdr *cur_record = &vd->vd.primary.rootdir;
585     uint8_t *temp = sec + ISO_SECTOR_SIZE;
586     int level = 0;
587 
588     read_iso_sector(ISO_PRIMARY_VD_SECTOR, sec,
589                     "Failed to read ISO primary descriptor");
590     sec_loc[0] = iso_733_to_u32(cur_record->ext_loc);
591     dir_rem[0] = 0;
592     sec_offset[0] = 0;
593 
594     while (level >= 0) {
595         IPL_assert(sec_offset[level] <= ISO_SECTOR_SIZE,
596                    "Directory tree structure violation");
597 
598         cur_record = (IsoDirHdr *)(temp + sec_offset[level]);
599 
600         if (sec_offset[level] == 0) {
601             read_iso_sector(sec_loc[level], temp,
602                             "Failed to read ISO directory");
603             if (dir_rem[level] == 0) {
604                 /* Skip self and parent records */
605                 dir_rem[level] = iso_733_to_u32(cur_record->data_len) -
606                                  cur_record->dr_len;
607                 sec_offset[level] += cur_record->dr_len;
608 
609                 cur_record = (IsoDirHdr *)(temp + sec_offset[level]);
610                 dir_rem[level] -= cur_record->dr_len;
611                 sec_offset[level] += cur_record->dr_len;
612                 continue;
613             }
614         }
615 
616         if (!cur_record->dr_len || sec_offset[level] == ISO_SECTOR_SIZE) {
617             /* Zero-padding and/or the end of current sector */
618             dir_rem[level] -= ISO_SECTOR_SIZE - sec_offset[level];
619             sec_offset[level] = 0;
620             sec_loc[level]++;
621         } else {
622             /* The directory record is valid */
623             if (load_rba == iso_733_to_u32(cur_record->ext_loc)) {
624                 return iso_733_to_u32(cur_record->data_len);
625             }
626 
627             dir_rem[level] -= cur_record->dr_len;
628             sec_offset[level] += cur_record->dr_len;
629 
630             if (cur_record->file_flags & 0x2) {
631                 /* Subdirectory */
632                 if (level == ISO9660_MAX_DIR_DEPTH - 1) {
633                     sclp_print("ISO-9660 directory depth limit exceeded\n");
634                 } else {
635                     level++;
636                     sec_loc[level] = iso_733_to_u32(cur_record->ext_loc);
637                     sec_offset[level] = 0;
638                     dir_rem[level] = 0;
639                     continue;
640                 }
641             }
642         }
643 
644         if (dir_rem[level] == 0) {
645             /* Nothing remaining */
646             level--;
647             read_iso_sector(sec_loc[level], temp,
648                             "Failed to read ISO directory");
649         }
650     }
651 
652     return 0;
653 }
654 
655 static void load_iso_bc_entry(IsoBcSection *load)
656 {
657     IsoBcSection s = *load;
658     /*
659      * According to spec, extent for each file
660      * is padded and ISO_SECTOR_SIZE bytes aligned
661      */
662     uint32_t blks_to_load = bswap16(s.sector_count) >> ET_SECTOR_SHIFT;
663     uint32_t real_size = iso_get_file_size(bswap32(s.load_rba));
664 
665     if (real_size) {
666         /* Round up blocks to load */
667         blks_to_load = (real_size + ISO_SECTOR_SIZE - 1) / ISO_SECTOR_SIZE;
668         sclp_print("ISO boot image size verified\n");
669     } else {
670         sclp_print("ISO boot image size could not be verified\n");
671     }
672 
673     read_iso_boot_image(bswap32(s.load_rba),
674                         (void *)((uint64_t)bswap16(s.load_segment)),
675                         blks_to_load);
676 
677     jump_to_low_kernel();
678 }
679 
680 static uint32_t find_iso_bc(void)
681 {
682     IsoVolDesc *vd = (IsoVolDesc *)sec;
683     uint32_t block_num = ISO_PRIMARY_VD_SECTOR;
684 
685     if (virtio_read_many(block_num++, sec, 1)) {
686         /* If primary vd cannot be read, there is no boot catalog */
687         return 0;
688     }
689 
690     while (is_iso_vd_valid(vd) && vd->type != VOL_DESC_TERMINATOR) {
691         if (vd->type == VOL_DESC_TYPE_BOOT) {
692             IsoVdElTorito *et = &vd->vd.boot;
693 
694             if (!memcmp(&et->el_torito[0], el_torito_magic, 32)) {
695                 return bswap32(et->bc_offset);
696             }
697         }
698         read_iso_sector(block_num++, sec,
699                         "Failed to read ISO volume descriptor");
700     }
701 
702     return 0;
703 }
704 
705 static IsoBcSection *find_iso_bc_entry(void)
706 {
707     IsoBcEntry *e = (IsoBcEntry *)sec;
708     uint32_t offset = find_iso_bc();
709     int i;
710     unsigned int loadparm = get_loadparm_index();
711 
712     if (!offset) {
713         return NULL;
714     }
715 
716     read_iso_sector(offset, sec, "Failed to read El Torito boot catalog");
717 
718     if (!is_iso_bc_valid(e)) {
719         /* The validation entry is mandatory */
720         panic("No valid boot catalog found!\n");
721         return NULL;
722     }
723 
724     /*
725      * Each entry has 32 bytes size, so one sector cannot contain > 64 entries.
726      * We consider only boot catalogs with no more than 64 entries.
727      */
728     for (i = 1; i < ISO_BC_ENTRY_PER_SECTOR; i++) {
729         if (e[i].id == ISO_BC_BOOTABLE_SECTION) {
730             if (is_iso_bc_entry_compatible(&e[i].body.sect)) {
731                 if (loadparm <= 1) {
732                     /* found, default, or unspecified */
733                     return &e[i].body.sect;
734                 }
735                 loadparm--;
736             }
737         }
738     }
739 
740     panic("No suitable boot entry found on ISO-9660 media!\n");
741 
742     return NULL;
743 }
744 
745 static void ipl_iso_el_torito(void)
746 {
747     IsoBcSection *s = find_iso_bc_entry();
748 
749     if (s) {
750         load_iso_bc_entry(s);
751         /* no return */
752     }
753 }
754 
755 /***********************************************************************
756  * Bus specific IPL sequences
757  */
758 
759 static void zipl_load_vblk(void)
760 {
761     if (virtio_guessed_disk_nature()) {
762         virtio_assume_iso9660();
763     }
764     ipl_iso_el_torito();
765 
766     if (virtio_guessed_disk_nature()) {
767         sclp_print("Using guessed DASD geometry.\n");
768         virtio_assume_eckd();
769     }
770     ipl_eckd();
771 }
772 
773 static void zipl_load_vscsi(void)
774 {
775     if (virtio_get_block_size() == VIRTIO_ISO_BLOCK_SIZE) {
776         /* Is it an ISO image in non-CD drive? */
777         ipl_iso_el_torito();
778     }
779 
780     sclp_print("Using guessed DASD geometry.\n");
781     virtio_assume_eckd();
782     ipl_eckd();
783 }
784 
785 /***********************************************************************
786  * IPL starts here
787  */
788 
789 void zipl_load(void)
790 {
791     VDev *vdev = virtio_get_device();
792 
793     if (vdev->is_cdrom) {
794         ipl_iso_el_torito();
795         panic("\n! Cannot IPL this ISO image !\n");
796     }
797 
798     if (virtio_get_device_type() == VIRTIO_ID_NET) {
799         jump_to_IPL_code(vdev->netboot_start_addr);
800     }
801 
802     ipl_scsi();
803 
804     switch (virtio_get_device_type()) {
805     case VIRTIO_ID_BLOCK:
806         zipl_load_vblk();
807         break;
808     case VIRTIO_ID_SCSI:
809         zipl_load_vscsi();
810         break;
811     default:
812         panic("\n! Unknown IPL device type !\n");
813     }
814 
815     panic("\n* this can never happen *\n");
816 }
817