xref: /qemu/pc-bios/s390-ccw/bootmap.c (revision 548de8f8)
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 <string.h>
12 #include <stdio.h>
13 #include "s390-ccw.h"
14 #include "s390-arch.h"
15 #include "bootmap.h"
16 #include "virtio.h"
17 #include "bswap.h"
18 
19 #ifdef DEBUG
20 /* #define DEBUG_FALLBACK */
21 #endif
22 
23 #ifdef DEBUG_FALLBACK
24 #define dputs(txt) \
25     do { printf("zipl: " txt); } while (0)
26 #else
27 #define dputs(fmt, ...) \
28     do { } while (0)
29 #endif
30 
31 /* Scratch space */
32 static uint8_t sec[MAX_SECTOR_SIZE*4] __attribute__((__aligned__(PAGE_SIZE)));
33 
34 const uint8_t el_torito_magic[] = "EL TORITO SPECIFICATION"
35                                   "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
36 
37 /*
38  * Match two CCWs located after PSW and eight filler bytes.
39  * From libmagic and arch/s390/kernel/head.S.
40  */
41 const uint8_t linux_s390_magic[] = "\x02\x00\x00\x18\x60\x00\x00\x50\x02\x00"
42                                    "\x00\x68\x60\x00\x00\x50\x40\x40\x40\x40"
43                                    "\x40\x40\x40\x40";
44 
45 static inline bool is_iso_vd_valid(IsoVolDesc *vd)
46 {
47     const uint8_t vol_desc_magic[] = "CD001";
48 
49     return !memcmp(&vd->ident[0], vol_desc_magic, 5) &&
50            vd->version == 0x1 &&
51            vd->type <= VOL_DESC_TYPE_PARTITION;
52 }
53 
54 /***********************************************************************
55  * IPL an ECKD DASD (CDL or LDL/CMS format)
56  */
57 
58 static unsigned char _bprs[8*1024]; /* guessed "max" ECKD sector size */
59 static const int max_bprs_entries = sizeof(_bprs) / sizeof(ExtEckdBlockPtr);
60 static uint8_t _s2[MAX_SECTOR_SIZE * 3] __attribute__((__aligned__(PAGE_SIZE)));
61 static void *s2_prev_blk = _s2;
62 static void *s2_cur_blk = _s2 + MAX_SECTOR_SIZE;
63 static void *s2_next_blk = _s2 + MAX_SECTOR_SIZE * 2;
64 
65 static inline int verify_boot_info(BootInfo *bip)
66 {
67     if (!magic_match(bip->magic, ZIPL_MAGIC)) {
68         puts("No zIPL sig in BootInfo");
69         return -EINVAL;
70     }
71     if (bip->version != BOOT_INFO_VERSION) {
72         puts("Wrong zIPL version");
73         return -EINVAL;
74     }
75     if (bip->bp_type != BOOT_INFO_BP_TYPE_IPL) {
76         puts("DASD is not for IPL");
77         return -ENODEV;
78     }
79     if (bip->dev_type != BOOT_INFO_DEV_TYPE_ECKD) {
80         puts("DASD is not ECKD");
81         return -ENODEV;
82     }
83     if (bip->flags != BOOT_INFO_FLAGS_ARCH) {
84         puts("Not for this arch");
85         return -EINVAL;
86     }
87     if (!block_size_ok(bip->bp.ipl.bm_ptr.eckd.bptr.size)) {
88         puts("Bad block size in zIPL section of 1st record");
89         return -EINVAL;
90     }
91 
92     return 0;
93 }
94 
95 static void eckd_format_chs(ExtEckdBlockPtr *ptr,  bool ldipl,
96                             uint64_t *c,
97                             uint64_t *h,
98                             uint64_t *s)
99 {
100     if (ldipl) {
101         *c = ptr->ldptr.chs.cylinder;
102         *h = ptr->ldptr.chs.head;
103         *s = ptr->ldptr.chs.sector;
104     } else {
105         *c = ptr->bptr.chs.cylinder;
106         *h = ptr->bptr.chs.head;
107         *s = ptr->bptr.chs.sector;
108     }
109 }
110 
111 static block_number_t eckd_chs_to_block(uint64_t c, uint64_t h, uint64_t s)
112 {
113     const uint64_t sectors = virtio_get_sectors();
114     const uint64_t heads = virtio_get_heads();
115     const uint64_t cylinder = c + ((h & 0xfff0) << 12);
116     const uint64_t head = h & 0x000f;
117     const block_number_t block = sectors * heads * cylinder
118                                + sectors * head
119                                + s - 1; /* block nr starts with zero */
120     return block;
121 }
122 
123 static block_number_t eckd_block_num(EckdCHS *chs)
124 {
125     return eckd_chs_to_block(chs->cylinder, chs->head, chs->sector);
126 }
127 
128 static block_number_t gen_eckd_block_num(ExtEckdBlockPtr *ptr, bool ldipl)
129 {
130     uint64_t cyl, head, sec;
131     eckd_format_chs(ptr, ldipl, &cyl, &head, &sec);
132     return eckd_chs_to_block(cyl, head, sec);
133 }
134 
135 static bool eckd_valid_chs(uint64_t cyl, uint64_t head, uint64_t sector)
136 {
137     if (head >= virtio_get_heads()
138         || sector > virtio_get_sectors()
139         || sector <= 0) {
140         return false;
141     }
142 
143     if (!virtio_guessed_disk_nature() &&
144         eckd_chs_to_block(cyl, head, sector) >= virtio_get_blocks()) {
145         return false;
146     }
147 
148     return true;
149 }
150 
151 static bool eckd_valid_address(ExtEckdBlockPtr *ptr, bool ldipl)
152 {
153     uint64_t cyl, head, sec;
154     eckd_format_chs(ptr, ldipl, &cyl, &head, &sec);
155     return eckd_valid_chs(cyl, head, sec);
156 }
157 
158 static block_number_t load_eckd_segments(block_number_t blk, bool ldipl,
159                                          uint64_t *address)
160 {
161     block_number_t block_nr;
162     int j, rc, count;
163     BootMapPointer *bprs = (void *)_bprs;
164     bool more_data;
165 
166     memset(_bprs, FREE_SPACE_FILLER, sizeof(_bprs));
167     if (virtio_read(blk, bprs)) {
168         puts("BPRS read failed");
169         return ERROR_BLOCK_NR;
170     }
171 
172     do {
173         more_data = false;
174         for (j = 0;; j++) {
175             block_nr = gen_eckd_block_num(&bprs[j].xeckd, ldipl);
176             if (is_null_block_number(block_nr)) { /* end of chunk */
177                 return NULL_BLOCK_NR;
178             }
179 
180             /* we need the updated blockno for the next indirect entry
181              * in the chain, but don't want to advance address
182              */
183             if (j == (max_bprs_entries - 1)) {
184                 break;
185             }
186 
187             /* List directed pointer does not store block size */
188             if (!ldipl && !block_size_ok(bprs[j].xeckd.bptr.size)) {
189                 puts("Bad chunk block size");
190                 return ERROR_BLOCK_NR;
191             }
192 
193             if (!eckd_valid_address(&bprs[j].xeckd, ldipl)) {
194                 /*
195                  * If an invalid address is found during LD-IPL then break and
196                  * retry as CCW-IPL, otherwise abort on error
197                  */
198                 if (!ldipl) {
199                     puts("Bad chunk ECKD address");
200                     return ERROR_BLOCK_NR;
201                 }
202                 break;
203             }
204 
205             if (ldipl) {
206                 count = bprs[j].xeckd.ldptr.count;
207             } else {
208                 count = bprs[j].xeckd.bptr.count;
209             }
210 
211             if (count == 0 && unused_space(&bprs[j + 1],
212                 sizeof(EckdBlockPtr))) {
213                 /* This is a "continue" pointer.
214                  * This ptr should be the last one in the current
215                  * script section.
216                  * I.e. the next ptr must point to the unused memory area
217                  */
218                 memset(_bprs, FREE_SPACE_FILLER, sizeof(_bprs));
219                 if (virtio_read(block_nr, bprs)) {
220                     puts("BPRS continuation read failed");
221                     return ERROR_BLOCK_NR;
222                 }
223                 more_data = true;
224                 break;
225             }
226 
227             /* Load (count+1) blocks of code at (block_nr)
228              * to memory (address).
229              */
230             rc = virtio_read_many(block_nr, (void *)(*address), count + 1);
231             if (rc != 0) {
232                 puts("Code chunk read failed");
233                 return ERROR_BLOCK_NR;
234             }
235 
236             *address += (count + 1) * virtio_get_block_size();
237         }
238     } while (more_data);
239     return block_nr;
240 }
241 
242 static bool find_zipl_boot_menu_banner(int *offset)
243 {
244     int i;
245 
246     /* Menu banner starts with "zIPL" */
247     for (i = 0; i <= virtio_get_block_size() - 4; i++) {
248         if (magic_match(s2_cur_blk + i, ZIPL_MAGIC_EBCDIC)) {
249             *offset = i;
250             return true;
251         }
252     }
253 
254     return false;
255 }
256 
257 static int eckd_get_boot_menu_index(block_number_t s1b_block_nr)
258 {
259     block_number_t cur_block_nr;
260     block_number_t prev_block_nr = 0;
261     block_number_t next_block_nr = 0;
262     EckdStage1b *s1b = (void *)sec;
263     int banner_offset;
264     int i;
265 
266     /* Get Stage1b data */
267     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
268     if (virtio_read(s1b_block_nr, s1b)) {
269         puts("Cannot read stage1b boot loader");
270         return -EIO;
271     }
272 
273     memset(_s2, FREE_SPACE_FILLER, sizeof(_s2));
274 
275     /* Get Stage2 data */
276     for (i = 0; i < STAGE2_BLK_CNT_MAX; i++) {
277         cur_block_nr = eckd_block_num(&s1b->seek[i].chs);
278 
279         if (!cur_block_nr || is_null_block_number(cur_block_nr)) {
280             break;
281         }
282 
283         if (virtio_read(cur_block_nr, s2_cur_blk)) {
284             puts("Cannot read stage2 boot loader");
285             return -EIO;
286         }
287 
288         if (find_zipl_boot_menu_banner(&banner_offset)) {
289             /*
290              * Load the adjacent blocks to account for the
291              * possibility of menu data spanning multiple blocks.
292              */
293             if (prev_block_nr) {
294                 if (virtio_read(prev_block_nr, s2_prev_blk)) {
295                     puts("Cannot read stage2 boot loader");
296                     return -EIO;
297                 }
298             }
299 
300             if (i + 1 < STAGE2_BLK_CNT_MAX) {
301                 next_block_nr = eckd_block_num(&s1b->seek[i + 1].chs);
302             }
303 
304             if (next_block_nr && !is_null_block_number(next_block_nr)) {
305                 if (virtio_read(next_block_nr, s2_next_blk)) {
306                     puts("Cannot read stage2 boot loader");
307                     return -EIO;
308                 }
309             }
310 
311             return menu_get_zipl_boot_index(s2_cur_blk + banner_offset);
312         }
313 
314         prev_block_nr = cur_block_nr;
315     }
316 
317     printf("No zipl boot menu data found. Booting default entry.");
318     return 0;
319 }
320 
321 static int run_eckd_boot_script(block_number_t bmt_block_nr,
322                                  block_number_t s1b_block_nr)
323 {
324     int i;
325     unsigned int loadparm = get_loadparm_index();
326     block_number_t block_nr;
327     uint64_t address;
328     BootMapTable *bmt = (void *)sec;
329     BootMapScript *bms = (void *)sec;
330     /* The S1B block number is NULL_BLOCK_NR if and only if it's an LD-IPL */
331     bool ldipl = (s1b_block_nr == NULL_BLOCK_NR);
332 
333     if (menu_is_enabled_zipl() && !ldipl) {
334         loadparm = eckd_get_boot_menu_index(s1b_block_nr);
335     }
336 
337     debug_print_int("loadparm", loadparm);
338     if (loadparm >= MAX_BOOT_ENTRIES) {
339         puts("loadparm value greater than max number of boot entries allowed");
340         return -EINVAL;
341     }
342 
343     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
344     if (virtio_read(bmt_block_nr, sec)) {
345         puts("Cannot read Boot Map Table");
346         return -EIO;
347     }
348 
349     block_nr = gen_eckd_block_num(&bmt->entry[loadparm].xeckd, ldipl);
350     if (block_nr == NULL_BLOCK_NR) {
351         puts("Cannot find Boot Map Table Entry");
352         return -EIO;
353     }
354 
355     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
356     if (virtio_read(block_nr, sec)) {
357         puts("Cannot read Boot Map Script");
358         return -EIO;
359     }
360 
361     for (i = 0; bms->entry[i].type == BOOT_SCRIPT_LOAD ||
362                 bms->entry[i].type == BOOT_SCRIPT_SIGNATURE; i++) {
363 
364         /* We don't support secure boot yet, so we skip signature entries */
365         if (bms->entry[i].type == BOOT_SCRIPT_SIGNATURE) {
366             continue;
367         }
368 
369         address = bms->entry[i].address.load_address;
370         block_nr = gen_eckd_block_num(&bms->entry[i].blkptr.xeckd, ldipl);
371 
372         do {
373             block_nr = load_eckd_segments(block_nr, ldipl, &address);
374             if (block_nr == ERROR_BLOCK_NR) {
375                 return ldipl ? 0 : -EIO;
376             }
377         } while (block_nr != NULL_BLOCK_NR);
378     }
379 
380     if (ldipl && bms->entry[i].type != BOOT_SCRIPT_EXEC) {
381         /* Abort LD-IPL and retry as CCW-IPL */
382         return 0;
383     }
384 
385     if (bms->entry[i].type != BOOT_SCRIPT_EXEC) {
386         puts("Unknown script entry type");
387         return -EINVAL;
388     }
389     write_reset_psw(bms->entry[i].address.load_address);
390     jump_to_IPL_code(0);
391     return -1;
392 }
393 
394 static int ipl_eckd_cdl(void)
395 {
396     XEckdMbr *mbr;
397     EckdCdlIpl2 *ipl2 = (void *)sec;
398     IplVolumeLabel *vlbl = (void *)sec;
399     block_number_t bmt_block_nr, s1b_block_nr;
400 
401     /* we have just read the block #0 and recognized it as "IPL1" */
402     puts("CDL");
403 
404     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
405     if (virtio_read(1, ipl2)) {
406         puts("Cannot read IPL2 record at block 1");
407         return -EIO;
408     }
409 
410     mbr = &ipl2->mbr;
411     if (!magic_match(mbr, ZIPL_MAGIC)) {
412         puts("No zIPL section in IPL2 record.");
413         return 0;
414     }
415     if (!block_size_ok(mbr->blockptr.xeckd.bptr.size)) {
416         puts("Bad block size in zIPL section of IPL2 record.");
417         return 0;
418     }
419     if (mbr->dev_type != DEV_TYPE_ECKD) {
420         puts("Non-ECKD device type in zIPL section of IPL2 record.");
421         return 0;
422     }
423 
424     /* save pointer to Boot Map Table */
425     bmt_block_nr = eckd_block_num(&mbr->blockptr.xeckd.bptr.chs);
426 
427     /* save pointer to Stage1b Data */
428     s1b_block_nr = eckd_block_num(&ipl2->stage1.seek[0].chs);
429 
430     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
431     if (virtio_read(2, vlbl)) {
432         puts("Cannot read Volume Label at block 2");
433         return -EIO;
434     }
435     if (!magic_match(vlbl->key, VOL1_MAGIC)) {
436         puts("Invalid magic of volume label block.");
437         return 0;
438     }
439     if (!magic_match(vlbl->f.key, VOL1_MAGIC)) {
440         puts("Invalid magic of volser block.");
441         return 0;
442     }
443     print_volser(vlbl->f.volser);
444 
445     return run_eckd_boot_script(bmt_block_nr, s1b_block_nr);
446 }
447 
448 static void print_eckd_ldl_msg(ECKD_IPL_mode_t mode)
449 {
450     LDL_VTOC *vlbl = (void *)sec; /* already read, 3rd block */
451     char msg[4] = { '?', '.', '\n', '\0' };
452 
453     printf((mode == ECKD_CMS) ? "CMS" : "LDL");
454     printf(" version ");
455     switch (vlbl->LDL_version) {
456     case LDL1_VERSION:
457         msg[0] = '1';
458         break;
459     case LDL2_VERSION:
460         msg[0] = '2';
461         break;
462     default:
463         msg[0] = ebc2asc[vlbl->LDL_version];
464         msg[1] = '?';
465         break;
466     }
467     printf("%s", msg);
468     print_volser(vlbl->volser);
469 }
470 
471 static int ipl_eckd_ldl(ECKD_IPL_mode_t mode)
472 {
473     block_number_t bmt_block_nr, s1b_block_nr;
474     EckdLdlIpl1 *ipl1 = (void *)sec;
475 
476     if (mode != ECKD_LDL_UNLABELED) {
477         print_eckd_ldl_msg(mode);
478     }
479 
480     /* DO NOT read BootMap pointer (only one, xECKD) at block #2 */
481 
482     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
483     if (virtio_read(0, sec)) {
484         puts("Cannot read block 0 to grab boot info.");
485         return -EIO;
486     }
487     if (mode == ECKD_LDL_UNLABELED) {
488         if (!magic_match(ipl1->bip.magic, ZIPL_MAGIC)) {
489             return 0; /* not applicable layout */
490         }
491         puts("unlabeled LDL.");
492     }
493     verify_boot_info(&ipl1->bip);
494 
495     /* save pointer to Boot Map Table */
496     bmt_block_nr = eckd_block_num(&ipl1->bip.bp.ipl.bm_ptr.eckd.bptr.chs);
497 
498     /* save pointer to Stage1b Data */
499     s1b_block_nr = eckd_block_num(&ipl1->stage1.seek[0].chs);
500 
501     return run_eckd_boot_script(bmt_block_nr, s1b_block_nr);
502 }
503 
504 static block_number_t eckd_find_bmt(ExtEckdBlockPtr *ptr)
505 {
506     block_number_t blockno;
507     uint8_t tmp_sec[MAX_SECTOR_SIZE];
508     BootRecord *br;
509 
510     blockno = gen_eckd_block_num(ptr, 0);
511     if (virtio_read(blockno, tmp_sec)) {
512         puts("Cannot read boot record");
513         return ERROR_BLOCK_NR;
514     }
515     br = (BootRecord *)tmp_sec;
516     if (!magic_match(br->magic, ZIPL_MAGIC)) {
517         /* If the boot record is invalid, return and try CCW-IPL instead */
518         return NULL_BLOCK_NR;
519     }
520 
521     return gen_eckd_block_num(&br->pgt.xeckd, 1);
522 }
523 
524 static void print_eckd_msg(void)
525 {
526     char msg[] = "Using ECKD scheme (block size *****), ";
527     char *p = &msg[34], *q = &msg[30];
528     int n = virtio_get_block_size();
529 
530     /* Fill in the block size and show up the message */
531     if (n > 0 && n <= 99999) {
532         while (n) {
533             *p-- = '0' + (n % 10);
534             n /= 10;
535         }
536         while (p >= q) {
537             *p-- = ' ';
538         }
539     }
540     printf("%s", msg);
541 }
542 
543 static int ipl_eckd(void)
544 {
545     IplVolumeLabel *vlbl = (void *)sec;
546     LDL_VTOC *vtoc = (void *)sec;
547     block_number_t ldipl_bmt; /* Boot Map Table for List-Directed IPL */
548 
549     print_eckd_msg();
550 
551     /* Block 2 can contain either the CDL VOL1 label or the LDL VTOC */
552     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
553     if (virtio_read(2, vlbl)) {
554         puts("Cannot read block 2");
555         return -EIO;
556     }
557 
558     /*
559      * First check for a list-directed-format pointer which would
560      * supersede the CCW pointer.
561      */
562     if (eckd_valid_address((ExtEckdBlockPtr *)&vlbl->f.br, 0)) {
563         ldipl_bmt = eckd_find_bmt((ExtEckdBlockPtr *)&vlbl->f.br);
564         switch (ldipl_bmt) {
565         case ERROR_BLOCK_NR:
566             return -EIO;
567         case NULL_BLOCK_NR:
568             break; /* Invalid BMT but the device may still boot with CCW-IPL */
569         default:
570             puts("List-Directed");
571             /*
572              * LD-IPL does not use the S1B bock, just make it NULL_BLOCK_NR.
573              * In some failure cases retry IPL before aborting.
574              */
575             if (run_eckd_boot_script(ldipl_bmt, NULL_BLOCK_NR)) {
576                 return -EIO;
577             }
578             /* Non-fatal error, retry as CCW-IPL */
579             printf("Retrying IPL ");
580             print_eckd_msg();
581         }
582         memset(sec, FREE_SPACE_FILLER, sizeof(sec));
583         if (virtio_read(2, vtoc)) {
584             puts("Cannot read block 2");
585             return -EIO;
586         }
587     }
588 
589     /* Not list-directed */
590     if (magic_match(vtoc->magic, VOL1_MAGIC)) {
591         if (ipl_eckd_cdl()) {
592             return -1;
593         }
594     }
595 
596     if (magic_match(vtoc->magic, CMS1_MAGIC)) {
597         return ipl_eckd_ldl(ECKD_CMS);
598     }
599     if (magic_match(vtoc->magic, LNX1_MAGIC)) {
600         return ipl_eckd_ldl(ECKD_LDL);
601     }
602 
603     if (ipl_eckd_ldl(ECKD_LDL_UNLABELED)) {
604         return -1;
605     }
606     /*
607      * Ok, it is not a LDL by any means.
608      * It still might be a CDL with zero record keys for IPL1 and IPL2
609      */
610     return ipl_eckd_cdl();
611 }
612 
613 /***********************************************************************
614  * IPL a SCSI disk
615  */
616 
617 static int zipl_load_segment(ComponentEntry *entry)
618 {
619     const int max_entries = (MAX_SECTOR_SIZE / sizeof(ScsiBlockPtr));
620     ScsiBlockPtr *bprs = (void *)sec;
621     const int bprs_size = sizeof(sec);
622     block_number_t blockno;
623     uint64_t address;
624     int i;
625     char err_msg[] = "zIPL failed to read BPRS at 0xZZZZZZZZZZZZZZZZ";
626     char *blk_no = &err_msg[30]; /* where to print blockno in (those ZZs) */
627 
628     blockno = entry->data.blockno;
629     address = entry->compdat.load_addr;
630 
631     debug_print_int("loading segment at block", blockno);
632     debug_print_int("addr", address);
633 
634     do {
635         memset(bprs, FREE_SPACE_FILLER, bprs_size);
636         fill_hex_val(blk_no, &blockno, sizeof(blockno));
637         if (virtio_read(blockno, bprs)) {
638             puts(err_msg);
639             return -EIO;
640         }
641 
642         for (i = 0;; i++) {
643             uint64_t *cur_desc = (void *)&bprs[i];
644 
645             blockno = bprs[i].blockno;
646             if (!blockno) {
647                 break;
648             }
649 
650             /* we need the updated blockno for the next indirect entry in the
651                chain, but don't want to advance address */
652             if (i == (max_entries - 1)) {
653                 break;
654             }
655 
656             if (bprs[i].blockct == 0 && unused_space(&bprs[i + 1],
657                 sizeof(ScsiBlockPtr))) {
658                 /* This is a "continue" pointer.
659                  * This ptr is the last one in the current script section.
660                  * I.e. the next ptr must point to the unused memory area.
661                  * The blockno is not zero, so the upper loop must continue
662                  * reading next section of BPRS.
663                  */
664                 break;
665             }
666             address = virtio_load_direct(cur_desc[0], cur_desc[1], 0,
667                                          (void *)address);
668             if (!address) {
669                 puts("zIPL load segment failed");
670                 return -EIO;
671             }
672         }
673     } while (blockno);
674 
675     return 0;
676 }
677 
678 /* Run a zipl program */
679 static int zipl_run(ScsiBlockPtr *pte)
680 {
681     ComponentHeader *header;
682     ComponentEntry *entry;
683     uint8_t tmp_sec[MAX_SECTOR_SIZE];
684 
685     if (virtio_read(pte->blockno, tmp_sec)) {
686         puts("Cannot read header");
687         return -EIO;
688     }
689     header = (ComponentHeader *)tmp_sec;
690 
691     if (!magic_match(tmp_sec, ZIPL_MAGIC)) {
692         puts("No zIPL magic in header");
693         return -EINVAL;
694     }
695     if (header->type != ZIPL_COMP_HEADER_IPL) {
696         puts("Bad header type");
697         return -EINVAL;
698     }
699 
700     dputs("start loading images\n");
701 
702     /* Load image(s) into RAM */
703     entry = (ComponentEntry *)(&header[1]);
704     while (entry->component_type == ZIPL_COMP_ENTRY_LOAD ||
705            entry->component_type == ZIPL_COMP_ENTRY_SIGNATURE) {
706 
707         /* We don't support secure boot yet, so we skip signature entries */
708         if (entry->component_type == ZIPL_COMP_ENTRY_SIGNATURE) {
709             entry++;
710             continue;
711         }
712 
713         if (zipl_load_segment(entry)) {
714             return -1;
715         }
716 
717         entry++;
718 
719         if ((uint8_t *)(&entry[1]) > (tmp_sec + MAX_SECTOR_SIZE)) {
720             puts("Wrong entry value");
721             return -EINVAL;
722         }
723     }
724 
725     if (entry->component_type != ZIPL_COMP_ENTRY_EXEC) {
726         puts("No EXEC entry");
727         return -EINVAL;
728     }
729 
730     /* should not return */
731     write_reset_psw(entry->compdat.load_psw);
732     jump_to_IPL_code(0);
733     return -1;
734 }
735 
736 static int ipl_scsi(void)
737 {
738     ScsiMbr *mbr = (void *)sec;
739     int program_table_entries = 0;
740     BootMapTable *prog_table = (void *)sec;
741     unsigned int loadparm = get_loadparm_index();
742     bool valid_entries[MAX_BOOT_ENTRIES] = {false};
743     size_t i;
744 
745     /* Grab the MBR */
746     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
747     if (virtio_read(0, mbr)) {
748         puts("Cannot read block 0");
749         return -EIO;
750     }
751 
752     if (!magic_match(mbr->magic, ZIPL_MAGIC)) {
753         return 0;
754     }
755 
756     puts("Using SCSI scheme.");
757     debug_print_int("MBR Version", mbr->version_id);
758     IPL_check(mbr->version_id == 1,
759               "Unknown MBR layout version, assuming version 1");
760     debug_print_int("program table", mbr->pt.blockno);
761     if (!mbr->pt.blockno) {
762         puts("No Program Table");
763         return -EINVAL;
764     }
765 
766     /* Parse the program table */
767     if (virtio_read(mbr->pt.blockno, sec)) {
768         puts("Error reading Program Table");
769         return -EIO;
770     }
771     if (!magic_match(sec, ZIPL_MAGIC)) {
772         puts("No zIPL magic in Program Table");
773         return -EINVAL;
774     }
775 
776     for (i = 0; i < MAX_BOOT_ENTRIES; i++) {
777         if (prog_table->entry[i].scsi.blockno) {
778             valid_entries[i] = true;
779             program_table_entries++;
780         }
781     }
782 
783     debug_print_int("program table entries", program_table_entries);
784     if (program_table_entries == 0) {
785         puts("Empty Program Table");
786         return -EINVAL;
787     }
788 
789     if (menu_is_enabled_enum()) {
790         loadparm = menu_get_enum_boot_index(valid_entries);
791     }
792 
793     debug_print_int("loadparm", loadparm);
794     if (loadparm >= MAX_BOOT_ENTRIES) {
795         puts("loadparm value greater than max number of boot entries allowed");
796         return -EINVAL;
797     }
798 
799     return zipl_run(&prog_table->entry[loadparm].scsi);
800 }
801 
802 /***********************************************************************
803  * IPL El Torito ISO9660 image or DVD
804  */
805 
806 static bool is_iso_bc_entry_compatible(IsoBcSection *s)
807 {
808     uint8_t *magic_sec = (uint8_t *)(sec + ISO_SECTOR_SIZE);
809 
810     if (s->unused || !s->sector_count) {
811         return false;
812     }
813     if (virtio_read(bswap32(s->load_rba), magic_sec)) {
814         puts("Failed to read image sector 0");
815         return false;
816     }
817 
818     /* Checking bytes 8 - 32 for S390 Linux magic */
819     return !memcmp(magic_sec + 8, linux_s390_magic, 24);
820 }
821 
822 /* Location of the current sector of the directory */
823 static uint32_t sec_loc[ISO9660_MAX_DIR_DEPTH];
824 /* Offset in the current sector of the directory */
825 static uint32_t sec_offset[ISO9660_MAX_DIR_DEPTH];
826 /* Remained directory space in bytes */
827 static uint32_t dir_rem[ISO9660_MAX_DIR_DEPTH];
828 
829 static inline long iso_get_file_size(uint32_t load_rba)
830 {
831     IsoVolDesc *vd = (IsoVolDesc *)sec;
832     IsoDirHdr *cur_record = &vd->vd.primary.rootdir;
833     uint8_t *temp = sec + ISO_SECTOR_SIZE;
834     int level = 0;
835 
836     if (virtio_read(ISO_PRIMARY_VD_SECTOR, sec)) {
837         puts("Failed to read ISO primary descriptor");
838         return -EIO;
839     }
840 
841     sec_loc[0] = iso_733_to_u32(cur_record->ext_loc);
842     dir_rem[0] = 0;
843     sec_offset[0] = 0;
844 
845     while (level >= 0) {
846         if (sec_offset[level] > ISO_SECTOR_SIZE) {
847             puts("Directory tree structure violation");
848             return -EIO;
849         }
850 
851         cur_record = (IsoDirHdr *)(temp + sec_offset[level]);
852 
853         if (sec_offset[level] == 0) {
854             if (virtio_read(sec_loc[level], temp)) {
855                 puts("Failed to read ISO directory");
856                 return -EIO;
857             }
858             if (dir_rem[level] == 0) {
859                 /* Skip self and parent records */
860                 dir_rem[level] = iso_733_to_u32(cur_record->data_len) -
861                                  cur_record->dr_len;
862                 sec_offset[level] += cur_record->dr_len;
863 
864                 cur_record = (IsoDirHdr *)(temp + sec_offset[level]);
865                 dir_rem[level] -= cur_record->dr_len;
866                 sec_offset[level] += cur_record->dr_len;
867                 continue;
868             }
869         }
870 
871         if (!cur_record->dr_len || sec_offset[level] == ISO_SECTOR_SIZE) {
872             /* Zero-padding and/or the end of current sector */
873             dir_rem[level] -= ISO_SECTOR_SIZE - sec_offset[level];
874             sec_offset[level] = 0;
875             sec_loc[level]++;
876         } else {
877             /* The directory record is valid */
878             if (load_rba == iso_733_to_u32(cur_record->ext_loc)) {
879                 return iso_733_to_u32(cur_record->data_len);
880             }
881 
882             dir_rem[level] -= cur_record->dr_len;
883             sec_offset[level] += cur_record->dr_len;
884 
885             if (cur_record->file_flags & 0x2) {
886                 /* Subdirectory */
887                 if (level == ISO9660_MAX_DIR_DEPTH - 1) {
888                     puts("ISO-9660 directory depth limit exceeded");
889                 } else {
890                     level++;
891                     sec_loc[level] = iso_733_to_u32(cur_record->ext_loc);
892                     sec_offset[level] = 0;
893                     dir_rem[level] = 0;
894                     continue;
895                 }
896             }
897         }
898 
899         if (dir_rem[level] == 0) {
900             /* Nothing remaining */
901             level--;
902             if (virtio_read(sec_loc[level], temp)) {
903                 puts("Failed to read ISO directory");
904                 return -EIO;
905             }
906         }
907     }
908 
909     return 0;
910 }
911 
912 static void load_iso_bc_entry(IsoBcSection *load)
913 {
914     IsoBcSection s = *load;
915     /*
916      * According to spec, extent for each file
917      * is padded and ISO_SECTOR_SIZE bytes aligned
918      */
919     uint32_t blks_to_load = bswap16(s.sector_count) >> ET_SECTOR_SHIFT;
920     long real_size = iso_get_file_size(bswap32(s.load_rba));
921 
922     if (real_size > 0) {
923         /* Round up blocks to load */
924         blks_to_load = (real_size + ISO_SECTOR_SIZE - 1) / ISO_SECTOR_SIZE;
925         puts("ISO boot image size verified");
926     } else {
927         puts("ISO boot image size could not be verified");
928         if (real_size < 0) {
929             return;
930         }
931     }
932 
933     if (read_iso_boot_image(bswap32(s.load_rba),
934                         (void *)((uint64_t)bswap16(s.load_segment)),
935                         blks_to_load)) {
936         return;
937     }
938 
939     jump_to_low_kernel();
940 }
941 
942 static uint32_t find_iso_bc(void)
943 {
944     IsoVolDesc *vd = (IsoVolDesc *)sec;
945     uint32_t block_num = ISO_PRIMARY_VD_SECTOR;
946 
947     if (virtio_read_many(block_num++, sec, 1)) {
948         /* If primary vd cannot be read, there is no boot catalog */
949         return 0;
950     }
951 
952     while (is_iso_vd_valid(vd) && vd->type != VOL_DESC_TERMINATOR) {
953         if (vd->type == VOL_DESC_TYPE_BOOT) {
954             IsoVdElTorito *et = &vd->vd.boot;
955 
956             if (!memcmp(&et->el_torito[0], el_torito_magic, 32)) {
957                 return bswap32(et->bc_offset);
958             }
959         }
960         if (virtio_read(block_num++, sec)) {
961             puts("Failed to read ISO volume descriptor");
962             return 0;
963         }
964     }
965 
966     return 0;
967 }
968 
969 static IsoBcSection *find_iso_bc_entry(uint32_t offset)
970 {
971     IsoBcEntry *e = (IsoBcEntry *)sec;
972     int i;
973     unsigned int loadparm = get_loadparm_index();
974 
975     if (!offset) {
976         return NULL;
977     }
978 
979     if (virtio_read(offset, sec)) {
980         puts("Failed to read El Torito boot catalog");
981         return NULL;
982     }
983 
984     if (!is_iso_bc_valid(e)) {
985         /* The validation entry is mandatory */
986         return NULL;
987     }
988 
989     /*
990      * Each entry has 32 bytes size, so one sector cannot contain > 64 entries.
991      * We consider only boot catalogs with no more than 64 entries.
992      */
993     for (i = 1; i < ISO_BC_ENTRY_PER_SECTOR; i++) {
994         if (e[i].id == ISO_BC_BOOTABLE_SECTION) {
995             if (is_iso_bc_entry_compatible(&e[i].body.sect)) {
996                 if (loadparm <= 1) {
997                     /* found, default, or unspecified */
998                     return &e[i].body.sect;
999                 }
1000                 loadparm--;
1001             }
1002         }
1003     }
1004 
1005     return NULL;
1006 }
1007 
1008 static int ipl_iso_el_torito(void)
1009 {
1010     uint32_t offset = find_iso_bc();
1011     if (!offset) {
1012         return 0;
1013     }
1014 
1015     IsoBcSection *s = find_iso_bc_entry(offset);
1016 
1017     if (s) {
1018         load_iso_bc_entry(s); /* only return in error */
1019         return -1;
1020     }
1021 
1022     puts("No suitable boot entry found on ISO-9660 media!");
1023     return -EIO;
1024 }
1025 
1026 /**
1027  * Detect whether we're trying to boot from an .ISO image.
1028  * These always have a signature string "CD001" at offset 0x8001.
1029  */
1030 static bool has_iso_signature(void)
1031 {
1032     int blksize = virtio_get_block_size();
1033 
1034     if (!blksize || virtio_read(0x8000 / blksize, sec)) {
1035         return false;
1036     }
1037 
1038     return !memcmp("CD001", &sec[1], 5);
1039 }
1040 
1041 /***********************************************************************
1042  * Bus specific IPL sequences
1043  */
1044 
1045 static int zipl_load_vblk(void)
1046 {
1047     int blksize = virtio_get_block_size();
1048 
1049     if (blksize == VIRTIO_ISO_BLOCK_SIZE || has_iso_signature()) {
1050         if (blksize != VIRTIO_ISO_BLOCK_SIZE) {
1051             virtio_assume_iso9660();
1052         }
1053         if (ipl_iso_el_torito()) {
1054             return 0;
1055         }
1056     }
1057 
1058     if (blksize != VIRTIO_DASD_DEFAULT_BLOCK_SIZE) {
1059         puts("Using guessed DASD geometry.");
1060         virtio_assume_eckd();
1061     }
1062     return ipl_eckd();
1063 }
1064 
1065 static int zipl_load_vscsi(void)
1066 {
1067     if (virtio_get_block_size() == VIRTIO_ISO_BLOCK_SIZE) {
1068         /* Is it an ISO image in non-CD drive? */
1069         if (ipl_iso_el_torito()) {
1070             return 0;
1071         }
1072     }
1073 
1074     puts("Using guessed DASD geometry.");
1075     virtio_assume_eckd();
1076     return ipl_eckd();
1077 }
1078 
1079 /***********************************************************************
1080  * IPL starts here
1081  */
1082 
1083 void zipl_load(void)
1084 {
1085     VDev *vdev = virtio_get_device();
1086 
1087     if (vdev->is_cdrom) {
1088         ipl_iso_el_torito();
1089         puts("Failed to IPL this ISO image!");
1090         return;
1091     }
1092 
1093     if (virtio_get_device_type() == VIRTIO_ID_NET) {
1094         netmain();
1095         puts("Failed to IPL from this network!");
1096         return;
1097     }
1098 
1099     if (ipl_scsi()) {
1100         puts("Failed to IPL from this SCSI device!");
1101         return;
1102     }
1103 
1104     switch (virtio_get_device_type()) {
1105     case VIRTIO_ID_BLOCK:
1106         zipl_load_vblk();
1107         break;
1108     case VIRTIO_ID_SCSI:
1109         zipl_load_vscsi();
1110         break;
1111     default:
1112         puts("Unknown IPL device type!");
1113         return;
1114     }
1115 
1116     puts("zIPL load failed!");
1117 }
1118