1 /*
2 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
3 * Copyright (c) 2012 Andrey V. Elsukov <ae@FreeBSD.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include <sys/cdefs.h>
29
30 /*
31 * BIOS disk device handling.
32 *
33 * Ideas and algorithms from:
34 *
35 * - NetBSD libi386/biosdisk.c
36 * - FreeBSD biosboot/disk.c
37 *
38 */
39
40 #include <sys/disk.h>
41 #include <sys/limits.h>
42 #include <sys/queue.h>
43 #include <stand.h>
44 #include <machine/bootinfo.h>
45 #include <stdarg.h>
46 #include <stdbool.h>
47
48 #include <bootstrap.h>
49 #include <btxv86.h>
50 #include <edd.h>
51 #include "disk.h"
52 #include "libi386.h"
53
54 #define BIOS_NUMDRIVES 0x475
55 #define BIOSDISK_SECSIZE 512
56 #define BUFSIZE (1 * BIOSDISK_SECSIZE)
57
58 #define DT_ATAPI 0x10 /* disk type for ATAPI floppies */
59 #define WDMAJOR 0 /* major numbers for devices we frontend for */
60 #define WFDMAJOR 1
61 #define FDMAJOR 2
62 #define DAMAJOR 4
63 #define ACDMAJOR 117
64 #define CDMAJOR 15
65
66 /*
67 * INT13 commands
68 */
69 #define CMD_RESET 0x0000
70 #define CMD_READ_CHS 0x0200
71 #define CMD_WRITE_CHS 0x0300
72 #define CMD_READ_PARAM 0x0800
73 #define CMD_DRIVE_TYPE 0x1500
74 #define CMD_CHECK_EDD 0x4100
75 #define CMD_READ_LBA 0x4200
76 #define CMD_WRITE_LBA 0x4300
77 #define CMD_EXT_PARAM 0x4800
78 #define CMD_CD_GET_STATUS 0x4b01
79
80 #define DISK_BIOS 0x13
81
82 #ifdef DISK_DEBUG
83 #define DPRINTF(fmt, args...) printf("%s: " fmt "\n", __func__, ## args)
84 #else
85 #define DPRINTF(fmt, args...) ((void)0)
86 #endif
87
88 struct specification_packet {
89 uint8_t sp_size;
90 uint8_t sp_bootmedia;
91 uint8_t sp_drive;
92 uint8_t sp_controller;
93 uint32_t sp_lba;
94 uint16_t sp_devicespec;
95 uint16_t sp_buffersegment;
96 uint16_t sp_loadsegment;
97 uint16_t sp_sectorcount;
98 uint16_t sp_cylsec;
99 uint8_t sp_head;
100 uint8_t sp_dummy[16]; /* Avoid memory corruption */
101 } __packed;
102
103 /*
104 * List of BIOS devices, translation from disk unit number to
105 * BIOS unit number.
106 */
107 typedef struct bdinfo
108 {
109 STAILQ_ENTRY(bdinfo) bd_link; /* link in device list */
110 int bd_unit; /* BIOS unit number */
111 int bd_cyl; /* BIOS geometry */
112 int bd_hds;
113 int bd_sec;
114 int bd_flags;
115 #define BD_MODEINT13 0x0000
116 #define BD_MODEEDD1 0x0001
117 #define BD_MODEEDD3 0x0002
118 #define BD_MODEEDD (BD_MODEEDD1 | BD_MODEEDD3)
119 #define BD_MODEMASK 0x0003
120 #define BD_FLOPPY 0x0004
121 #define BD_CDROM 0x0008
122 #define BD_NO_MEDIA 0x0010
123 int bd_type; /* BIOS 'drive type' (floppy only) */
124 uint16_t bd_sectorsize; /* Sector size */
125 uint64_t bd_sectors; /* Disk size */
126 int bd_open; /* reference counter */
127 void *bd_bcache; /* buffer cache data */
128 } bdinfo_t;
129
130 #define BD_RD 0
131 #define BD_WR 1
132
133 typedef STAILQ_HEAD(bdinfo_list, bdinfo) bdinfo_list_t;
134 static bdinfo_list_t fdinfo = STAILQ_HEAD_INITIALIZER(fdinfo);
135 static bdinfo_list_t cdinfo = STAILQ_HEAD_INITIALIZER(cdinfo);
136 static bdinfo_list_t hdinfo = STAILQ_HEAD_INITIALIZER(hdinfo);
137
138 static void bd_io_workaround(bdinfo_t *);
139 static int bd_io(struct disk_devdesc *, bdinfo_t *, daddr_t, int, caddr_t, int);
140 static bool bd_int13probe(bdinfo_t *);
141
142 static int bd_init(void);
143 static int cd_init(void);
144 static int fd_init(void);
145 static int bd_strategy(void *devdata, int flag, daddr_t dblk, size_t size,
146 char *buf, size_t *rsize);
147 static int bd_realstrategy(void *devdata, int flag, daddr_t dblk, size_t size,
148 char *buf, size_t *rsize);
149 static int bd_open(struct open_file *f, ...);
150 static int bd_close(struct open_file *f);
151 static int bd_ioctl(struct open_file *f, ulong_t cmd, void *data);
152 static int bd_print(int verbose);
153 static int cd_print(int verbose);
154 static int fd_print(int verbose);
155 static void bd_reset_disk(int);
156 static int bd_get_diskinfo_std(struct bdinfo *);
157
158 struct devsw biosfd = {
159 .dv_name = "fd",
160 .dv_type = DEVT_FD,
161 .dv_init = fd_init,
162 .dv_strategy = bd_strategy,
163 .dv_open = bd_open,
164 .dv_close = bd_close,
165 .dv_ioctl = bd_ioctl,
166 .dv_print = fd_print,
167 .dv_cleanup = NULL
168 };
169
170 struct devsw bioscd = {
171 .dv_name = "cd",
172 .dv_type = DEVT_CD,
173 .dv_init = cd_init,
174 .dv_strategy = bd_strategy,
175 .dv_open = bd_open,
176 .dv_close = bd_close,
177 .dv_ioctl = bd_ioctl,
178 .dv_print = cd_print,
179 .dv_cleanup = NULL
180 };
181
182 struct devsw bioshd = {
183 .dv_name = "disk",
184 .dv_type = DEVT_DISK,
185 .dv_init = bd_init,
186 .dv_strategy = bd_strategy,
187 .dv_open = bd_open,
188 .dv_close = bd_close,
189 .dv_ioctl = bd_ioctl,
190 .dv_print = bd_print,
191 .dv_cleanup = NULL
192 };
193
194 static bdinfo_list_t *
bd_get_bdinfo_list(struct devsw * dev)195 bd_get_bdinfo_list(struct devsw *dev)
196 {
197 if (dev->dv_type == DEVT_DISK)
198 return (&hdinfo);
199 if (dev->dv_type == DEVT_CD)
200 return (&cdinfo);
201 if (dev->dv_type == DEVT_FD)
202 return (&fdinfo);
203 return (NULL);
204 }
205
206 /* XXX this gets called way way too often, investigate */
207 static bdinfo_t *
bd_get_bdinfo(struct devdesc * dev)208 bd_get_bdinfo(struct devdesc *dev)
209 {
210 bdinfo_list_t *bdi;
211 bdinfo_t *bd = NULL;
212 int unit;
213
214 bdi = bd_get_bdinfo_list(dev->d_dev);
215 if (bdi == NULL)
216 return (bd);
217
218 unit = 0;
219 STAILQ_FOREACH(bd, bdi, bd_link) {
220 if (unit == dev->d_unit)
221 return (bd);
222 unit++;
223 }
224 return (bd);
225 }
226
227 /*
228 * Translate between BIOS device numbers and our private unit numbers.
229 */
230 int
bd_bios2unit(int biosdev)231 bd_bios2unit(int biosdev)
232 {
233 bdinfo_list_t *bdi[] = { &fdinfo, &cdinfo, &hdinfo, NULL };
234 bdinfo_t *bd;
235 int i, unit;
236
237 DPRINTF("looking for bios device 0x%x", biosdev);
238 for (i = 0; bdi[i] != NULL; i++) {
239 unit = 0;
240 STAILQ_FOREACH(bd, bdi[i], bd_link) {
241 if (bd->bd_unit == biosdev) {
242 DPRINTF("bd unit %d is BIOS device 0x%x", unit,
243 bd->bd_unit);
244 return (unit);
245 }
246 unit++;
247 }
248 }
249 return (-1);
250 }
251
252 int
bd_unit2bios(struct i386_devdesc * dev)253 bd_unit2bios(struct i386_devdesc *dev)
254 {
255 bdinfo_list_t *bdi;
256 bdinfo_t *bd;
257 int unit;
258
259 bdi = bd_get_bdinfo_list(dev->dd.d_dev);
260 if (bdi == NULL)
261 return (-1);
262
263 unit = 0;
264 STAILQ_FOREACH(bd, bdi, bd_link) {
265 if (unit == dev->dd.d_unit)
266 return (bd->bd_unit);
267 unit++;
268 }
269 return (-1);
270 }
271
272 /*
273 * Use INT13 AH=15 - Read Drive Type.
274 */
275 static int
fd_count(void)276 fd_count(void)
277 {
278 int drive;
279
280 bd_reset_disk(0);
281
282 for (drive = 0; drive < MAXBDDEV; drive++) {
283 v86.ctl = V86_FLAGS;
284 v86.addr = DISK_BIOS;
285 v86.eax = CMD_DRIVE_TYPE;
286 v86.edx = drive;
287 v86int();
288
289 if (V86_CY(v86.efl))
290 break;
291
292 if ((v86.eax & 0x300) == 0)
293 break;
294 }
295
296 return (drive);
297 }
298
299 /*
300 * Quiz the BIOS for disk devices, save a little info about them.
301 */
302 static int
fd_init(void)303 fd_init(void)
304 {
305 int unit, numfd;
306 bdinfo_t *bd;
307
308 numfd = fd_count();
309 for (unit = 0; unit < numfd; unit++) {
310 if ((bd = calloc(1, sizeof (*bd))) == NULL)
311 break;
312
313 bd->bd_sectorsize = BIOSDISK_SECSIZE;
314 bd->bd_flags = BD_FLOPPY;
315 bd->bd_unit = unit;
316
317 /* Use std diskinfo for floppy drive */
318 if (bd_get_diskinfo_std(bd) != 0) {
319 free(bd);
320 break;
321 }
322 if (bd->bd_sectors == 0)
323 bd->bd_flags |= BD_NO_MEDIA;
324 printf("BIOS drive %c: is %s%d\n", ('A' + unit),
325 biosfd.dv_name, unit);
326 STAILQ_INSERT_TAIL(&fdinfo, bd, bd_link);
327 }
328
329 bcache_add_dev(unit);
330 return (0);
331 }
332
333 static int
bd_init(void)334 bd_init(void)
335 {
336 int base, unit;
337 bdinfo_t *bd;
338
339 base = 0x80;
340 for (unit = 0; unit < *(unsigned char *)PTOV(BIOS_NUMDRIVES); unit++) {
341 /*
342 * Check the BIOS equipment list for number of fixed disks.
343 */
344 if ((bd = calloc(1, sizeof (*bd))) == NULL)
345 break;
346 bd->bd_unit = base + unit;
347 if (!bd_int13probe(bd)) {
348 free(bd);
349 break;
350 }
351 printf("BIOS drive %c: is %s%d\n", ('C' + unit),
352 bioshd.dv_name, unit);
353 STAILQ_INSERT_TAIL(&hdinfo, bd, bd_link);
354 }
355 bcache_add_dev(unit);
356 return (0);
357 }
358
359 /*
360 * We can't quiz, we have to be told what device to use, so this function
361 * doesn't do anything. Instead, the loader calls bc_add() with the BIOS
362 * device number to add.
363 */
364 static int
cd_init(void)365 cd_init(void)
366 {
367
368 return (0);
369 }
370
371 /*
372 * Information from bootable CD-ROM.
373 */
374 static int
bd_get_diskinfo_cd(struct bdinfo * bd)375 bd_get_diskinfo_cd(struct bdinfo *bd)
376 {
377 struct specification_packet bc_sp;
378 int ret = -1;
379
380 (void) memset(&bc_sp, 0, sizeof (bc_sp));
381 /* Set sp_size as per specification. */
382 bc_sp.sp_size = sizeof (bc_sp) - sizeof (bc_sp.sp_dummy);
383
384 v86.ctl = V86_FLAGS;
385 v86.addr = DISK_BIOS;
386 v86.eax = CMD_CD_GET_STATUS;
387 v86.edx = bd->bd_unit;
388 v86.ds = VTOPSEG(&bc_sp);
389 v86.esi = VTOPOFF(&bc_sp);
390 v86int();
391
392 if ((v86.eax & 0xff00) == 0 &&
393 bc_sp.sp_drive == bd->bd_unit) {
394 bd->bd_cyl = ((bc_sp.sp_cylsec & 0xc0) << 2) +
395 ((bc_sp.sp_cylsec & 0xff00) >> 8) + 1;
396 bd->bd_sec = bc_sp.sp_cylsec & 0x3f;
397 bd->bd_hds = bc_sp.sp_head + 1;
398 bd->bd_sectors = (uint64_t)bd->bd_cyl * bd->bd_hds * bd->bd_sec;
399
400 if (bc_sp.sp_bootmedia & 0x0F) {
401 /* Floppy or hard-disk emulation */
402 bd->bd_sectorsize = BIOSDISK_SECSIZE;
403 return (-1);
404 } else {
405 bd->bd_sectorsize = 2048;
406 bd->bd_flags = BD_MODEEDD | BD_CDROM;
407 ret = 0;
408 }
409 }
410
411 /*
412 * If this is the boot_drive, default to non-emulation bootable CD-ROM.
413 */
414 if (ret != 0 && bd->bd_unit >= 0x88) {
415 bd->bd_cyl = 0;
416 bd->bd_hds = 1;
417 bd->bd_sec = 15;
418 bd->bd_sectorsize = 2048;
419 bd->bd_flags = BD_MODEEDD | BD_CDROM;
420 bd->bd_sectors = 0;
421 ret = 0;
422 }
423
424 /*
425 * Note we can not use bd_get_diskinfo_ext() nor bd_get_diskinfo_std()
426 * here - some systems do get hung with those.
427 */
428 /*
429 * Still no size? use 7.961GB. The size does not really matter
430 * as long as it is reasonably large to make our reads to pass
431 * the sector count check.
432 */
433 if (bd->bd_sectors == 0)
434 bd->bd_sectors = 4173824;
435
436 return (ret);
437 }
438
439 int
bc_add(int biosdev)440 bc_add(int biosdev)
441 {
442 bdinfo_t *bd;
443 int nbcinfo = 0;
444
445 if (!STAILQ_EMPTY(&cdinfo))
446 return (-1);
447
448 if ((bd = calloc(1, sizeof (*bd))) == NULL)
449 return (-1);
450
451 bd->bd_unit = biosdev;
452 if (bd_get_diskinfo_cd(bd) < 0) {
453 free(bd);
454 return (-1);
455 }
456
457 STAILQ_INSERT_TAIL(&cdinfo, bd, bd_link);
458 printf("BIOS CD is cd%d\n", nbcinfo);
459 nbcinfo++;
460 bcache_add_dev(nbcinfo); /* register cd device in bcache */
461 return (0);
462 }
463
464 /*
465 * Return EDD version or 0 if EDD is not supported on this drive.
466 */
467 static int
bd_check_extensions(int unit)468 bd_check_extensions(int unit)
469 {
470 /* do not use ext calls for floppy devices */
471 if (unit < 0x80)
472 return (0);
473
474 /* Determine if we can use EDD with this device. */
475 v86.ctl = V86_FLAGS;
476 v86.addr = DISK_BIOS;
477 v86.eax = CMD_CHECK_EDD;
478 v86.edx = unit;
479 v86.ebx = EDD_QUERY_MAGIC;
480 v86int();
481
482 if (V86_CY(v86.efl) || /* carry set */
483 (v86.ebx & 0xffff) != EDD_INSTALLED) /* signature */
484 return (0);
485
486 /* extended disk access functions (AH=42h-44h,47h,48h) supported */
487 if ((v86.ecx & EDD_INTERFACE_FIXED_DISK) == 0)
488 return (0);
489
490 return ((v86.eax >> 8) & 0xff);
491 }
492
493 static void
bd_reset_disk(int unit)494 bd_reset_disk(int unit)
495 {
496 /* reset disk */
497 v86.ctl = V86_FLAGS;
498 v86.addr = DISK_BIOS;
499 v86.eax = CMD_RESET;
500 v86.edx = unit;
501 v86int();
502 }
503
504 /*
505 * Read CHS info. Return 0 on success, error otherwise.
506 */
507 static int
bd_get_diskinfo_std(struct bdinfo * bd)508 bd_get_diskinfo_std(struct bdinfo *bd)
509 {
510 bzero(&v86, sizeof (v86));
511 v86.ctl = V86_FLAGS;
512 v86.addr = DISK_BIOS;
513 v86.eax = CMD_READ_PARAM;
514 v86.edx = bd->bd_unit;
515 v86int();
516
517 if (V86_CY(v86.efl) && ((v86.eax & 0xff00) != 0))
518 return ((v86.eax & 0xff00) >> 8);
519
520 /* return custom error on absurd sector number */
521 if ((v86.ecx & 0x3f) == 0)
522 return (0x60);
523
524 bd->bd_cyl = ((v86.ecx & 0xc0) << 2) + ((v86.ecx & 0xff00) >> 8) + 1;
525 /* Convert max head # -> # of heads */
526 bd->bd_hds = ((v86.edx & 0xff00) >> 8) + 1;
527 bd->bd_sec = v86.ecx & 0x3f;
528 bd->bd_type = v86.ebx;
529 bd->bd_sectors = (uint64_t)bd->bd_cyl * bd->bd_hds * bd->bd_sec;
530
531 return (0);
532 }
533
534 /*
535 * Read EDD info. Return 0 on success, error otherwise.
536 *
537 * Avoid stack corruption on some systems by adding extra bytes to
538 * params block.
539 */
540 static int
bd_get_diskinfo_ext(struct bdinfo * bd)541 bd_get_diskinfo_ext(struct bdinfo *bd)
542 {
543 struct disk_params {
544 struct edd_params head;
545 struct edd_device_path_v3 device_path;
546 uint8_t dummy[16];
547 } __packed dparams;
548 struct edd_params *params;
549 uint64_t total;
550
551 params = &dparams.head;
552 /* Get disk params */
553 bzero(&dparams, sizeof (dparams));
554 params->len = sizeof (struct edd_params_v3);
555 v86.ctl = V86_FLAGS;
556 v86.addr = DISK_BIOS;
557 v86.eax = CMD_EXT_PARAM;
558 v86.edx = bd->bd_unit;
559 v86.ds = VTOPSEG(&dparams);
560 v86.esi = VTOPOFF(&dparams);
561 v86int();
562
563 if (V86_CY(v86.efl) && ((v86.eax & 0xff00) != 0))
564 return ((v86.eax & 0xff00) >> 8);
565
566 /*
567 * Sector size must be a multiple of 512 bytes.
568 * An alternate test would be to check power of 2,
569 * powerof2(params.sector_size).
570 * 16K is largest read buffer we can use at this time.
571 */
572 if (params->sector_size >= 512 &&
573 params->sector_size <= 16384 &&
574 (params->sector_size % BIOSDISK_SECSIZE) == 0)
575 bd->bd_sectorsize = params->sector_size;
576
577 bd->bd_cyl = params->cylinders;
578 bd->bd_hds = params->heads;
579 bd->bd_sec = params->sectors_per_track;
580
581 if (params->sectors != 0) {
582 total = params->sectors;
583 } else {
584 total = (uint64_t)params->cylinders *
585 params->heads * params->sectors_per_track;
586 }
587 bd->bd_sectors = total;
588
589 return (0);
590 }
591
592 /*
593 * Try to detect a device supported by the legacy int13 BIOS
594 */
595 static bool
bd_int13probe(bdinfo_t * bd)596 bd_int13probe(bdinfo_t *bd)
597 {
598 int edd, ret;
599
600 bd->bd_flags &= ~BD_NO_MEDIA;
601
602 if ((bd->bd_flags & BD_CDROM) != 0) {
603 return (bd_get_diskinfo_cd(bd) == 0);
604 }
605
606 edd = bd_check_extensions(bd->bd_unit);
607 if (edd == 0)
608 bd->bd_flags |= BD_MODEINT13;
609 else if (edd < 0x30)
610 bd->bd_flags |= BD_MODEEDD1;
611 else
612 bd->bd_flags |= BD_MODEEDD3;
613
614 /* Default sector size */
615 if (bd->bd_sectorsize == 0)
616 bd->bd_sectorsize = BIOSDISK_SECSIZE;
617
618 /*
619 * Test if the floppy device is present, so we can avoid receiving
620 * bogus information from bd_get_diskinfo_std().
621 */
622 if (bd->bd_unit < 0x80) {
623 /* reset disk */
624 bd_reset_disk(bd->bd_unit);
625
626 /* Get disk type */
627 v86.ctl = V86_FLAGS;
628 v86.addr = DISK_BIOS;
629 v86.eax = CMD_DRIVE_TYPE;
630 v86.edx = bd->bd_unit;
631 v86int();
632 if (V86_CY(v86.efl) || (v86.eax & 0x300) == 0)
633 return (false);
634 }
635
636 ret = 1;
637 if (edd != 0)
638 ret = bd_get_diskinfo_ext(bd);
639 if (ret != 0 || bd->bd_sectors == 0)
640 ret = bd_get_diskinfo_std(bd);
641
642 if (ret != 0 && bd->bd_unit < 0x80) {
643 /* Set defaults for 1.44 floppy */
644 bd->bd_cyl = 80;
645 bd->bd_hds = 2;
646 bd->bd_sec = 18;
647 bd->bd_sectors = 2880;
648 /* Since we are there, there most likely is no media */
649 bd->bd_flags |= BD_NO_MEDIA;
650 ret = 0;
651 }
652
653 if (ret != 0) {
654 if (bd->bd_sectors != 0 && edd != 0) {
655 bd->bd_sec = 63;
656 bd->bd_hds = 255;
657 bd->bd_cyl =
658 (bd->bd_sectors + bd->bd_sec * bd->bd_hds - 1) /
659 bd->bd_sec * bd->bd_hds;
660 } else {
661 const char *dv_name;
662
663 if ((bd->bd_flags & BD_FLOPPY) != 0)
664 dv_name = biosfd.dv_name;
665 else
666 dv_name = bioshd.dv_name;
667
668 printf("Can not get information about %s unit %#x\n",
669 dv_name, bd->bd_unit);
670 return (false);
671 }
672 }
673
674 if (bd->bd_sec == 0)
675 bd->bd_sec = 63;
676 if (bd->bd_hds == 0)
677 bd->bd_hds = 255;
678
679 if (bd->bd_sectors == 0)
680 bd->bd_sectors = (uint64_t)bd->bd_cyl * bd->bd_hds * bd->bd_sec;
681
682 DPRINTF("unit 0x%x geometry %d/%d/%d\n", bd->bd_unit, bd->bd_cyl,
683 bd->bd_hds, bd->bd_sec);
684
685 return (true);
686 }
687
688 static int
bd_count(bdinfo_list_t * bdi)689 bd_count(bdinfo_list_t *bdi)
690 {
691 bdinfo_t *bd;
692 int i;
693
694 i = 0;
695 STAILQ_FOREACH(bd, bdi, bd_link)
696 i++;
697 return (i);
698 }
699
700 /*
701 * Print information about disks
702 */
703 static int
bd_print_common(struct devsw * dev,bdinfo_list_t * bdi,int verbose)704 bd_print_common(struct devsw *dev, bdinfo_list_t *bdi, int verbose)
705 {
706 char line[80];
707 struct disk_devdesc devd;
708 bdinfo_t *bd;
709 int i, ret = 0;
710 char drive;
711
712 if (STAILQ_EMPTY(bdi))
713 return (0);
714
715 printf("%s devices:", dev->dv_name);
716 if ((ret = pager_output("\n")) != 0)
717 return (ret);
718
719 i = -1;
720 STAILQ_FOREACH(bd, bdi, bd_link) {
721 i++;
722
723 switch (dev->dv_type) {
724 case DEVT_FD:
725 drive = 'A';
726 break;
727 case DEVT_CD:
728 drive = 'C' + bd_count(&hdinfo);
729 break;
730 default:
731 drive = 'C';
732 break;
733 }
734
735 snprintf(line, sizeof (line),
736 " %s%d: BIOS drive %c (%s%ju X %u):\n",
737 dev->dv_name, i, drive + i,
738 (bd->bd_flags & BD_NO_MEDIA) == BD_NO_MEDIA ?
739 "no media, " : "",
740 (uintmax_t)bd->bd_sectors,
741 bd->bd_sectorsize);
742 if ((ret = pager_output(line)) != 0)
743 break;
744
745 if ((bd->bd_flags & BD_NO_MEDIA) == BD_NO_MEDIA)
746 continue;
747
748 if (dev->dv_type != DEVT_DISK)
749 continue;
750
751 devd.dd.d_dev = dev;
752 devd.dd.d_unit = i;
753 devd.d_slice = D_SLICENONE;
754 devd.d_partition = D_PARTNONE;
755 if (disk_open(&devd,
756 bd->bd_sectorsize * bd->bd_sectors,
757 bd->bd_sectorsize) == 0) {
758 snprintf(line, sizeof (line), " %s%d",
759 dev->dv_name, i);
760 ret = disk_print(&devd, line, verbose);
761 disk_close(&devd);
762 if (ret != 0)
763 break;
764 }
765 }
766 return (ret);
767 }
768
769 static int
fd_print(int verbose)770 fd_print(int verbose)
771 {
772 return (bd_print_common(&biosfd, &fdinfo, verbose));
773 }
774
775 static int
bd_print(int verbose)776 bd_print(int verbose)
777 {
778 return (bd_print_common(&bioshd, &hdinfo, verbose));
779 }
780
781 static int
cd_print(int verbose)782 cd_print(int verbose)
783 {
784 return (bd_print_common(&bioscd, &cdinfo, verbose));
785 }
786
787 /*
788 * Read disk size from partition.
789 * This is needed to work around buggy BIOS systems returning
790 * wrong (truncated) disk media size.
791 * During bd_probe() we tested if the multiplication of bd_sectors
792 * would overflow so it should be safe to perform here.
793 */
794 static uint64_t
bd_disk_get_sectors(struct disk_devdesc * dev)795 bd_disk_get_sectors(struct disk_devdesc *dev)
796 {
797 bdinfo_t *bd;
798 struct disk_devdesc disk;
799 uint64_t size;
800
801 bd = bd_get_bdinfo(&dev->dd);
802 if (bd == NULL)
803 return (0);
804
805 disk.dd.d_dev = dev->dd.d_dev;
806 disk.dd.d_unit = dev->dd.d_unit;
807 disk.d_slice = D_SLICENONE;
808 disk.d_partition = D_PARTNONE;
809 disk.d_offset = 0;
810
811 size = bd->bd_sectors * bd->bd_sectorsize;
812 if (disk_open(&disk, size, bd->bd_sectorsize) == 0) {
813 (void) disk_ioctl(&disk, DIOCGMEDIASIZE, &size);
814 disk_close(&disk);
815 }
816 return (size / bd->bd_sectorsize);
817 }
818
819 /*
820 * Attempt to open the disk described by (dev) for use by (f).
821 *
822 * Note that the philosophy here is "give them exactly what
823 * they ask for". This is necessary because being too "smart"
824 * about what the user might want leads to complications.
825 * (eg. given no slice or partition value, with a disk that is
826 * sliced - are they after the first BSD slice, or the DOS
827 * slice before it?)
828 */
829 static int
bd_open(struct open_file * f,...)830 bd_open(struct open_file *f, ...)
831 {
832 bdinfo_t *bd;
833 struct disk_devdesc *dev;
834 va_list ap;
835 int rc;
836
837 va_start(ap, f);
838 dev = va_arg(ap, struct disk_devdesc *);
839 va_end(ap);
840
841 bd = bd_get_bdinfo(&dev->dd);
842 if (bd == NULL)
843 return (EIO);
844
845 if ((bd->bd_flags & BD_NO_MEDIA) == BD_NO_MEDIA) {
846 if (!bd_int13probe(bd))
847 return (EIO);
848 if ((bd->bd_flags & BD_NO_MEDIA) == BD_NO_MEDIA)
849 return (EIO);
850 }
851 if (bd->bd_bcache == NULL)
852 bd->bd_bcache = bcache_allocate();
853
854 if (bd->bd_open == 0)
855 bd->bd_sectors = bd_disk_get_sectors(dev);
856 bd->bd_open++;
857
858 rc = 0;
859 if (dev->dd.d_dev->dv_type == DEVT_DISK) {
860 rc = disk_open(dev, bd->bd_sectors * bd->bd_sectorsize,
861 bd->bd_sectorsize);
862 if (rc != 0) {
863 bd->bd_open--;
864 if (bd->bd_open == 0) {
865 bcache_free(bd->bd_bcache);
866 bd->bd_bcache = NULL;
867 }
868 }
869 }
870 return (rc);
871 }
872
873 static int
bd_close(struct open_file * f)874 bd_close(struct open_file *f)
875 {
876 struct disk_devdesc *dev;
877 bdinfo_t *bd;
878 int rc = 0;
879
880 dev = (struct disk_devdesc *)f->f_devdata;
881 bd = bd_get_bdinfo(&dev->dd);
882 if (bd == NULL)
883 return (EIO);
884
885 bd->bd_open--;
886 if (bd->bd_open == 0) {
887 bcache_free(bd->bd_bcache);
888 bd->bd_bcache = NULL;
889 }
890 if (dev->dd.d_dev->dv_type == DEVT_DISK)
891 rc = disk_close(dev);
892 return (rc);
893 }
894
895 static int
bd_ioctl(struct open_file * f,ulong_t cmd,void * data)896 bd_ioctl(struct open_file *f, ulong_t cmd, void *data)
897 {
898 bdinfo_t *bd;
899 struct disk_devdesc *dev;
900 int rc;
901
902 dev = (struct disk_devdesc *)f->f_devdata;
903 bd = bd_get_bdinfo(&dev->dd);
904 if (bd == NULL)
905 return (EIO);
906
907 if (dev->dd.d_dev->dv_type == DEVT_DISK) {
908 rc = disk_ioctl(dev, cmd, data);
909 if (rc != ENOTTY)
910 return (rc);
911 }
912
913 switch (cmd) {
914 case DIOCGSECTORSIZE:
915 *(uint32_t *)data = bd->bd_sectorsize;
916 break;
917 case DIOCGMEDIASIZE:
918 *(uint64_t *)data = bd->bd_sectors * bd->bd_sectorsize;
919 break;
920 default:
921 return (ENOTTY);
922 }
923 return (0);
924 }
925
926 static int
bd_strategy(void * devdata,int rw,daddr_t dblk,size_t size,char * buf,size_t * rsize)927 bd_strategy(void *devdata, int rw, daddr_t dblk, size_t size,
928 char *buf, size_t *rsize)
929 {
930 bdinfo_t *bd;
931 struct bcache_devdata bcd;
932 struct disk_devdesc *dev;
933 daddr_t offset;
934
935 dev = (struct disk_devdesc *)devdata;
936 bd = bd_get_bdinfo(&dev->dd);
937 if (bd == NULL)
938 return (EINVAL);
939
940 bcd.dv_strategy = bd_realstrategy;
941 bcd.dv_devdata = devdata;
942 bcd.dv_cache = bd->bd_bcache;
943
944 offset = 0;
945 if (dev->dd.d_dev->dv_type == DEVT_DISK) {
946
947 offset = dev->d_offset * bd->bd_sectorsize;
948 offset /= BIOSDISK_SECSIZE;
949 }
950 return (bcache_strategy(&bcd, rw, dblk + offset, size,
951 buf, rsize));
952 }
953
954 static int
bd_realstrategy(void * devdata,int rw,daddr_t dblk,size_t size,char * buf,size_t * rsize)955 bd_realstrategy(void *devdata, int rw, daddr_t dblk, size_t size,
956 char *buf, size_t *rsize)
957 {
958 struct disk_devdesc *dev = (struct disk_devdesc *)devdata;
959 bdinfo_t *bd;
960 uint64_t disk_blocks, offset, d_offset;
961 size_t blks, blkoff, bsize, bio_size, rest;
962 caddr_t bbuf = NULL;
963 int rc;
964
965 bd = bd_get_bdinfo(&dev->dd);
966 if (bd == NULL || (bd->bd_flags & BD_NO_MEDIA) == BD_NO_MEDIA)
967 return (EIO);
968
969 /*
970 * First make sure the IO size is a multiple of 512 bytes. While we do
971 * process partial reads below, the strategy mechanism is built
972 * assuming IO is a multiple of 512B blocks. If the request is not
973 * a multiple of 512B blocks, it has to be some sort of bug.
974 */
975 if (size == 0 || (size % BIOSDISK_SECSIZE) != 0) {
976 printf("bd_strategy: %d bytes I/O not multiple of %d\n",
977 size, BIOSDISK_SECSIZE);
978 return (EIO);
979 }
980
981 DPRINTF("open_disk %p", dev);
982
983 offset = dblk * BIOSDISK_SECSIZE;
984 dblk = offset / bd->bd_sectorsize;
985 blkoff = offset % bd->bd_sectorsize;
986
987 /*
988 * Check the value of the size argument. We do have quite small
989 * heap (64MB), but we do not know good upper limit, so we check against
990 * INT_MAX here. This will also protect us against possible overflows
991 * while translating block count to bytes.
992 */
993 if (size > INT_MAX) {
994 DPRINTF("too large I/O: %zu bytes", size);
995 return (EIO);
996 }
997
998 blks = size / bd->bd_sectorsize;
999 if (blks == 0 || (size % bd->bd_sectorsize) != 0)
1000 blks++;
1001
1002 if (dblk > dblk + blks)
1003 return (EIO);
1004
1005 if (rsize)
1006 *rsize = 0;
1007
1008 /*
1009 * Get disk blocks, this value is either for whole disk or for
1010 * partition.
1011 */
1012 d_offset = 0;
1013 disk_blocks = 0;
1014 if (dev->dd.d_dev->dv_type == DEVT_DISK) {
1015 if (disk_ioctl(dev, DIOCGMEDIASIZE, &disk_blocks) == 0) {
1016 /* DIOCGMEDIASIZE does return bytes. */
1017 disk_blocks /= bd->bd_sectorsize;
1018 }
1019 d_offset = dev->d_offset;
1020 }
1021 if (disk_blocks == 0)
1022 disk_blocks = bd->bd_sectors - d_offset;
1023
1024 /* Validate source block address. */
1025 if (dblk < d_offset || dblk >= d_offset + disk_blocks)
1026 return (EIO);
1027
1028 /*
1029 * Truncate if we are crossing disk or partition end.
1030 */
1031 if (dblk + blks >= d_offset + disk_blocks) {
1032 blks = d_offset + disk_blocks - dblk;
1033 size = blks * bd->bd_sectorsize;
1034 DPRINTF("short I/O %d", blks);
1035 }
1036
1037 bio_size = min(BIO_BUFFER_SIZE, size);
1038 while (bio_size > bd->bd_sectorsize) {
1039 bbuf = bio_alloc(bio_size);
1040 if (bbuf != NULL)
1041 break;
1042 bio_size -= bd->bd_sectorsize;
1043 }
1044 if (bbuf == NULL) {
1045 bio_size = V86_IO_BUFFER_SIZE;
1046 if (bio_size < bd->bd_sectorsize)
1047 panic("BUG: Real mode buffer is too small");
1048
1049 /* Use alternate 4k buffer */
1050 bbuf = PTOV(V86_IO_BUFFER);
1051 }
1052 rest = size;
1053 rc = 0;
1054 while (blks > 0) {
1055 int x = min(blks, bio_size / bd->bd_sectorsize);
1056
1057 switch (rw & F_MASK) {
1058 case F_READ:
1059 DPRINTF("read %d from %lld to %p", x, dblk, buf);
1060 bsize = bd->bd_sectorsize * x - blkoff;
1061 if (rest < bsize)
1062 bsize = rest;
1063
1064 if ((rc = bd_io(dev, bd, dblk, x, bbuf, BD_RD)) != 0) {
1065 rc = EIO;
1066 goto error;
1067 }
1068
1069 bcopy(bbuf + blkoff, buf, bsize);
1070 break;
1071 case F_WRITE :
1072 DPRINTF("write %d from %lld to %p", x, dblk, buf);
1073 if (blkoff != 0) {
1074 /*
1075 * We got offset to sector, read 1 sector to
1076 * bbuf.
1077 */
1078 x = 1;
1079 bsize = bd->bd_sectorsize - blkoff;
1080 bsize = min(bsize, rest);
1081 rc = bd_io(dev, bd, dblk, x, bbuf, BD_RD);
1082 } else if (rest < bd->bd_sectorsize) {
1083 /*
1084 * The remaining block is not full
1085 * sector. Read 1 sector to bbuf.
1086 */
1087 x = 1;
1088 bsize = rest;
1089 rc = bd_io(dev, bd, dblk, x, bbuf, BD_RD);
1090 } else {
1091 /* We can write full sector(s). */
1092 bsize = bd->bd_sectorsize * x;
1093 }
1094 /*
1095 * Put your Data In, Put your Data out,
1096 * Put your Data In, and shake it all about
1097 */
1098 bcopy(buf, bbuf + blkoff, bsize);
1099 if ((rc = bd_io(dev, bd, dblk, x, bbuf, BD_WR)) != 0) {
1100 rc = EIO;
1101 goto error;
1102 }
1103 break;
1104 default:
1105 /* DO NOTHING */
1106 rc = EROFS;
1107 goto error;
1108 }
1109
1110 blkoff = 0;
1111 buf += bsize;
1112 rest -= bsize;
1113 blks -= x;
1114 dblk += x;
1115 }
1116
1117 if (rsize != NULL)
1118 *rsize = size;
1119 error:
1120 if (bbuf != PTOV(V86_IO_BUFFER))
1121 bio_free(bbuf, bio_size);
1122 return (rc);
1123 }
1124
1125 static int
bd_edd_io(bdinfo_t * bd,daddr_t dblk,int blks,caddr_t dest,int dowrite)1126 bd_edd_io(bdinfo_t *bd, daddr_t dblk, int blks, caddr_t dest,
1127 int dowrite)
1128 {
1129 static struct edd_packet packet;
1130
1131 packet.len = sizeof (struct edd_packet);
1132 packet.count = blks;
1133 packet.off = VTOPOFF(dest);
1134 packet.seg = VTOPSEG(dest);
1135 packet.lba = dblk;
1136 v86.ctl = V86_FLAGS;
1137 v86.addr = DISK_BIOS;
1138 if (dowrite == BD_WR)
1139 v86.eax = CMD_WRITE_LBA; /* maybe Write with verify 0x4302? */
1140 else
1141 v86.eax = CMD_READ_LBA;
1142 v86.edx = bd->bd_unit;
1143 v86.ds = VTOPSEG(&packet);
1144 v86.esi = VTOPOFF(&packet);
1145 v86int();
1146 if (V86_CY(v86.efl))
1147 return (v86.eax >> 8);
1148 return (0);
1149 }
1150
1151 static int
bd_chs_io(bdinfo_t * bd,daddr_t dblk,int blks,caddr_t dest,int dowrite)1152 bd_chs_io(bdinfo_t *bd, daddr_t dblk, int blks, caddr_t dest,
1153 int dowrite)
1154 {
1155 uint32_t x, bpc, cyl, hd, sec;
1156
1157 bpc = bd->bd_sec * bd->bd_hds; /* blocks per cylinder */
1158 x = dblk;
1159 cyl = x / bpc; /* block # / blocks per cylinder */
1160 x %= bpc; /* block offset into cylinder */
1161 hd = x / bd->bd_sec; /* offset / blocks per track */
1162 sec = x % bd->bd_sec; /* offset into track */
1163
1164 /* correct sector number for 1-based BIOS numbering */
1165 sec++;
1166
1167 if (cyl > 1023) {
1168 /* CHS doesn't support cylinders > 1023. */
1169 return (1);
1170 }
1171
1172 v86.ctl = V86_FLAGS;
1173 v86.addr = DISK_BIOS;
1174 if (dowrite == BD_WR)
1175 v86.eax = CMD_WRITE_CHS | blks;
1176 else
1177 v86.eax = CMD_READ_CHS | blks;
1178 v86.ecx = ((cyl & 0xff) << 8) | ((cyl & 0x300) >> 2) | sec;
1179 v86.edx = (hd << 8) | bd->bd_unit;
1180 v86.es = VTOPSEG(dest);
1181 v86.ebx = VTOPOFF(dest);
1182 v86int();
1183 if (V86_CY(v86.efl))
1184 return (v86.eax >> 8);
1185 return (0);
1186 }
1187
1188 static void
bd_io_workaround(bdinfo_t * bd)1189 bd_io_workaround(bdinfo_t *bd)
1190 {
1191 uint8_t buf[8 * 1024];
1192
1193 bd_edd_io(bd, 0xffffffff, 1, (caddr_t)buf, BD_RD);
1194 }
1195
1196 static int
bd_io(struct disk_devdesc * dev,bdinfo_t * bd,daddr_t dblk,int blks,caddr_t dest,int dowrite)1197 bd_io(struct disk_devdesc *dev, bdinfo_t *bd, daddr_t dblk, int blks,
1198 caddr_t dest, int dowrite)
1199 {
1200 int result, retry;
1201
1202 /* Just in case some idiot actually tries to read/write -1 blocks... */
1203 if (blks < 0)
1204 return (-1);
1205
1206 /*
1207 * Workaround for a problem with some HP ProLiant BIOS failing to work
1208 * out the boot disk after installation. hrs and kuriyama discovered
1209 * this problem with an HP ProLiant DL320e Gen 8 with a 3TB HDD, and
1210 * discovered that an int13h call seems to cause a buffer overrun in
1211 * the bios. The problem is alleviated by doing an extra read before
1212 * the buggy read. It is not immediately known whether other models
1213 * are similarly affected.
1214 * Loop retrying the operation a couple of times. The BIOS
1215 * may also retry.
1216 */
1217 if (dowrite == BD_RD && dblk >= 0x100000000)
1218 bd_io_workaround(bd);
1219 for (retry = 0; retry < 3; retry++) {
1220 if (bd->bd_flags & BD_MODEEDD)
1221 result = bd_edd_io(bd, dblk, blks, dest, dowrite);
1222 else
1223 result = bd_chs_io(bd, dblk, blks, dest, dowrite);
1224
1225 if (result == 0) {
1226 if (bd->bd_flags & BD_NO_MEDIA)
1227 bd->bd_flags &= ~BD_NO_MEDIA;
1228 break;
1229 }
1230
1231 bd_reset_disk(bd->bd_unit);
1232
1233 /*
1234 * Error codes:
1235 * 20h controller failure
1236 * 31h no media in drive (IBM/MS INT 13 extensions)
1237 * 80h no media in drive, VMWare (Fusion)
1238 * There is no reason to repeat the IO with errors above.
1239 */
1240 if (result == 0x20 || result == 0x31 || result == 0x80) {
1241 bd->bd_flags |= BD_NO_MEDIA;
1242 break;
1243 }
1244 }
1245
1246 if (result != 0 && (bd->bd_flags & BD_NO_MEDIA) == 0) {
1247 if (dowrite == BD_WR) {
1248 printf("%s%d: Write %d sector(s) from %p (0x%x) "
1249 "to %lld: 0x%x\n", dev->dd.d_dev->dv_name,
1250 dev->dd.d_unit, blks, dest, VTOP(dest), dblk,
1251 result);
1252 } else {
1253 printf("%s%d: Read %d sector(s) from %lld to %p "
1254 "(0x%x): 0x%x\n", dev->dd.d_dev->dv_name,
1255 dev->dd.d_unit, blks, dblk, dest, VTOP(dest),
1256 result);
1257 }
1258 }
1259
1260 return (result);
1261 }
1262
1263 /*
1264 * Return the BIOS geometry of a given "fixed drive" in a format
1265 * suitable for the legacy bootinfo structure. Since the kernel is
1266 * expecting raw int 0x13/0x8 values for N_BIOS_GEOM drives, we
1267 * prefer to get the information directly, rather than rely on being
1268 * able to put it together from information already maintained for
1269 * different purposes and for a probably different number of drives.
1270 *
1271 * For valid drives, the geometry is expected in the format (31..0)
1272 * "000000cc cccccccc hhhhhhhh 00ssssss"; and invalid drives are
1273 * indicated by returning the geometry of a "1.2M" PC-format floppy
1274 * disk. And, incidentally, what is returned is not the geometry as
1275 * such but the highest valid cylinder, head, and sector numbers.
1276 */
1277 uint32_t
bd_getbigeom(int bunit)1278 bd_getbigeom(int bunit)
1279 {
1280
1281 v86.ctl = V86_FLAGS;
1282 v86.addr = DISK_BIOS;
1283 v86.eax = CMD_READ_PARAM;
1284 v86.edx = 0x80 + bunit;
1285 v86int();
1286 if (V86_CY(v86.efl))
1287 return (0x4f010f);
1288 return (((v86.ecx & 0xc0) << 18) | ((v86.ecx & 0xff00) << 8) |
1289 (v86.edx & 0xff00) | (v86.ecx & 0x3f));
1290 }
1291
1292 /*
1293 * Return a suitable dev_t value for (dev).
1294 *
1295 * In the case where it looks like (dev) is a SCSI disk, we allow the number of
1296 * IDE disks to be specified in $num_ide_disks. There should be a Better Way.
1297 */
1298 int
bd_getdev(struct i386_devdesc * d)1299 bd_getdev(struct i386_devdesc *d)
1300 {
1301 struct disk_devdesc *dev;
1302 bdinfo_t *bd;
1303 int biosdev;
1304 int major;
1305 int rootdev;
1306 char *nip, *cp;
1307 int i, unit, slice, partition;
1308
1309 /* XXX: Assume partition 'a'. */
1310 slice = 0;
1311 partition = 0;
1312
1313 dev = (struct disk_devdesc *)d;
1314 bd = bd_get_bdinfo(&dev->dd);
1315 if (bd == NULL)
1316 return (-1);
1317
1318 biosdev = bd_unit2bios(d);
1319 DPRINTF("unit %d BIOS device %d", dev->dd.d_unit, biosdev);
1320 if (biosdev == -1) /* not a BIOS device */
1321 return (-1);
1322
1323 if (dev->dd.d_dev->dv_type == DEVT_DISK) {
1324 if (disk_open(dev, bd->bd_sectors * bd->bd_sectorsize,
1325 bd->bd_sectorsize) != 0) /* oops, not a viable device */
1326 return (-1);
1327 else
1328 disk_close(dev);
1329 slice = dev->d_slice + 1;
1330 partition = dev->d_partition;
1331 }
1332
1333 if (biosdev < 0x80) {
1334 /* floppy (or emulated floppy) or ATAPI device */
1335 if (bd->bd_type == DT_ATAPI) {
1336 /* is an ATAPI disk */
1337 major = WFDMAJOR;
1338 } else {
1339 /* is a floppy disk */
1340 major = FDMAJOR;
1341 }
1342 } else {
1343 /* assume an IDE disk */
1344 major = WDMAJOR;
1345 }
1346 /* default root disk unit number */
1347 unit = biosdev & 0x7f;
1348
1349 if (dev->dd.d_dev->dv_type == DEVT_CD) {
1350 /*
1351 * XXX: Need to examine device spec here to figure out if
1352 * SCSI or ATAPI. No idea on how to figure out device number.
1353 * All we can really pass to the kernel is what bus and device
1354 * on which bus we were booted from, which dev_t isn't well
1355 * suited to since those number don't match to unit numbers
1356 * very well. We may just need to engage in a hack where
1357 * we pass -C to the boot args if we are the boot device.
1358 */
1359 major = ACDMAJOR;
1360 unit = 0; /* XXX */
1361 }
1362
1363 /* XXX a better kludge to set the root disk unit number */
1364 if ((nip = getenv("root_disk_unit")) != NULL) {
1365 i = strtol(nip, &cp, 0);
1366 /* check for parse error */
1367 if ((cp != nip) && (*cp == 0))
1368 unit = i;
1369 }
1370
1371 rootdev = MAKEBOOTDEV(major, slice, unit, partition);
1372 DPRINTF("dev is 0x%x\n", rootdev);
1373 return (rootdev);
1374 }
1375