boot2.c revision 219225 
1/*-
2 * Copyright (c) 2008-2009 TAKAHASHI Yoshihiro
3 * Copyright (c) 1998 Robert Nordier
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms are freely
7 * permitted provided that the above copyright notice and this
8 * paragraph and the following disclaimer are duplicated in all
9 * such forms.
10 *
11 * This software is provided "AS IS" and without any express or
12 * implied warranties, including, without limitation, the implied
13 * warranties of merchantability and fitness for a particular
14 * purpose.
15 */
16
17#include <sys/cdefs.h>
18__FBSDID("$FreeBSD: head/sys/boot/pc98/boot2/boot2.c 219225 2011-03-03 11:45:54Z nyan $");
19
20#include <sys/param.h>
21#include <sys/disklabel.h>
22#include <sys/diskpc98.h>
23#include <sys/dirent.h>
24#include <sys/reboot.h>
25
26#include <machine/bootinfo.h>
27#include <machine/cpufunc.h>
28#include <machine/elf.h>
29#include <machine/psl.h>
30
31#include <stdarg.h>
32
33#include <a.out.h>
34
35#include <btxv86.h>
36
37#include "boot2.h"
38#include "lib.h"
39
40#define IO_KEYBOARD	1
41#define IO_SERIAL	2
42
43#define SECOND		1	/* Circa that many ticks in a second. */
44
45#define RBX_ASKNAME	0x0	/* -a */
46#define RBX_SINGLE	0x1	/* -s */
47/* 0x2 is reserved for log2(RB_NOSYNC). */
48/* 0x3 is reserved for log2(RB_HALT). */
49/* 0x4 is reserved for log2(RB_INITNAME). */
50#define RBX_DFLTROOT	0x5	/* -r */
51#define RBX_KDB 	0x6	/* -d */
52/* 0x7 is reserved for log2(RB_RDONLY). */
53/* 0x8 is reserved for log2(RB_DUMP). */
54/* 0x9 is reserved for log2(RB_MINIROOT). */
55#define RBX_CONFIG	0xa	/* -c */
56#define RBX_VERBOSE	0xb	/* -v */
57#define RBX_SERIAL	0xc	/* -h */
58#define RBX_CDROM	0xd	/* -C */
59/* 0xe is reserved for log2(RB_POWEROFF). */
60#define RBX_GDB 	0xf	/* -g */
61#define RBX_MUTE	0x10	/* -m */
62/* 0x11 is reserved for log2(RB_SELFTEST). */
63/* 0x12 is reserved for boot programs. */
64/* 0x13 is reserved for boot programs. */
65#define RBX_PAUSE	0x14	/* -p */
66#define RBX_QUIET	0x15	/* -q */
67#define RBX_NOINTR	0x1c	/* -n */
68/* 0x1d is reserved for log2(RB_MULTIPLE) and is just misnamed here. */
69#define RBX_DUAL	0x1d	/* -D */
70/* 0x1f is reserved for log2(RB_BOOTINFO). */
71
72/* pass: -a, -s, -r, -d, -c, -v, -h, -C, -g, -m, -p, -D */
73#define RBX_MASK	(OPT_SET(RBX_ASKNAME) | OPT_SET(RBX_SINGLE) | \
74			OPT_SET(RBX_DFLTROOT) | OPT_SET(RBX_KDB ) | \
75			OPT_SET(RBX_CONFIG) | OPT_SET(RBX_VERBOSE) | \
76			OPT_SET(RBX_SERIAL) | OPT_SET(RBX_CDROM) | \
77			OPT_SET(RBX_GDB ) | OPT_SET(RBX_MUTE) | \
78			OPT_SET(RBX_PAUSE) | OPT_SET(RBX_DUAL))
79
80#define PATH_CONFIG	"/boot.config"
81#define PATH_BOOT3	"/boot/loader"
82#define PATH_KERNEL	"/boot/kernel/kernel"
83
84#define ARGS		0x900
85#define NOPT		14
86#define NDEV		3
87#define V86_CY(x)	((x) & PSL_C)
88#define V86_ZR(x)	((x) & PSL_Z)
89
90#define DRV_DISK	0xf0
91#define DRV_UNIT	0x0f
92
93#define TYPE_AD		0
94#define TYPE_DA		1
95#define TYPE_FD		2
96
97#define OPT_SET(opt)	(1 << (opt))
98#define OPT_CHECK(opt)	((opts) & OPT_SET(opt))
99
100extern uint32_t _end;
101
102static const char optstr[NOPT] = "DhaCcdgmnpqrsv"; /* Also 'P', 'S' */
103static const unsigned char flags[NOPT] = {
104    RBX_DUAL,
105    RBX_SERIAL,
106    RBX_ASKNAME,
107    RBX_CDROM,
108    RBX_CONFIG,
109    RBX_KDB,
110    RBX_GDB,
111    RBX_MUTE,
112    RBX_NOINTR,
113    RBX_PAUSE,
114    RBX_QUIET,
115    RBX_DFLTROOT,
116    RBX_SINGLE,
117    RBX_VERBOSE
118};
119
120static const char *const dev_nm[NDEV] = {"ad", "da", "fd"};
121static const unsigned char dev_maj[NDEV] = {30, 4, 2};
122static const unsigned char dev_daua[NDEV] = {0x80, 0xa0, 0x90};
123
124static struct dsk {
125    unsigned daua;
126    unsigned type;
127    unsigned disk;
128    unsigned unit;
129    unsigned head;
130    unsigned sec;
131    unsigned slice;
132    unsigned part;
133    unsigned start;
134} dsk;
135static char cmd[512], cmddup[512];
136static const char *kname = NULL;
137static uint32_t opts;
138static int comspeed = SIOSPD;
139static struct bootinfo bootinfo;
140static unsigned ioctrl = IO_KEYBOARD;
141
142void exit(int);
143static void load(void);
144static int parse(void);
145static int xfsread(ino_t, void *, size_t);
146static int dskread(void *, unsigned, unsigned);
147static void printf(const char *,...);
148static void putchar(int);
149static int drvread(void *, unsigned);
150static int keyhit(unsigned);
151static int xputc(int);
152static int xgetc(int);
153static int getc(int);
154
155static void memcpy(void *, const void *, int);
156static void
157memcpy(void *dst, const void *src, int len)
158{
159    const char *s = src;
160    char *d = dst;
161
162    while (len--)
163        *d++ = *s++;
164}
165
166static inline int
167strcmp(const char *s1, const char *s2)
168{
169    for (; *s1 == *s2 && *s1; s1++, s2++);
170    return (unsigned char)*s1 - (unsigned char)*s2;
171}
172
173#define	UFS_SMALL_CGBASE
174#include "ufsread.c"
175
176static inline int
177xfsread(ino_t inode, void *buf, size_t nbyte)
178{
179    if ((size_t)fsread(inode, buf, nbyte) != nbyte) {
180	printf("Invalid %s\n", "format");
181	return -1;
182    }
183    return 0;
184}
185
186static inline void
187getstr(void)
188{
189    char *s;
190    int c;
191
192    s = cmd;
193    for (;;) {
194	switch (c = xgetc(0)) {
195	case 0:
196	    break;
197	case '\177':
198	case '\b':
199	    if (s > cmd) {
200		s--;
201		printf("\b \b");
202	    }
203	    break;
204	case '\n':
205	case '\r':
206	    *s = 0;
207	    return;
208	default:
209	    if (s - cmd < sizeof(cmd) - 1)
210		*s++ = c;
211	    putchar(c);
212	}
213    }
214}
215
216static inline void
217putc(int c)
218{
219
220    v86.ctl = V86_ADDR | V86_CALLF | V86_FLAGS;
221    v86.addr = PUTCORG;		/* call to putc in boot1 */
222    v86.eax = c;
223    v86int();
224    v86.ctl = V86_FLAGS;
225}
226
227static inline int
228is_scsi_hd(void)
229{
230
231    if ((*(u_char *)PTOV(0x482) >> dsk.unit) & 0x01)
232	return 1;
233
234    return 0;
235}
236
237static inline void
238fix_sector_size(void)
239{
240    u_char *p;
241
242    p = (u_char *)PTOV(0x460 + dsk.unit * 4);	/* SCSI equipment parameter */
243
244    if ((p[0] & 0x1f) == 7) {		/* SCSI MO */
245	if (!(p[3] & 0x30)) {		/* 256B / sector */
246	    p[3] |= 0x10;		/* forced set 512B / sector */
247	    p[3 + 0xa1000] |= 0x10;
248	}
249    }
250}
251
252static inline uint32_t
253get_diskinfo(void)
254{
255
256    if (dsk.disk == 0x30) {				/* 1440KB FD */
257	/* 80 cylinders, 2 heads, 18 sectors */
258	return (80 << 16) | (2 << 8) | 18;
259    } else if (dsk.disk == 0x90) {			/* 1200KB FD */
260	/* 80 cylinders, 2 heads, 15 sectors */
261	return (80 << 16) | (2 << 8) | 15;
262    } else if (dsk.disk == 0x80 || is_scsi_hd()) {	/* IDE or SCSI HDD */
263	v86.addr = 0x1b;
264	v86.eax = 0x8400 | dsk.daua;
265	v86int();
266	return (v86.ecx << 16) | v86.edx;
267    }
268
269    /* SCSI MO or CD */
270    fix_sector_size();	/* SCSI MO */
271
272    /* other SCSI devices */
273    return (65535 << 16) | (8 << 8) | 32;
274}
275
276static void
277set_dsk(void)
278{
279    uint32_t di;
280
281    di = get_diskinfo();
282
283    dsk.head = (di >> 8) & 0xff;
284    dsk.sec = di & 0xff;
285    dsk.start = 0;
286}
287
288#ifdef GET_BIOSGEOM
289static uint32_t
290bd_getbigeom(int bunit)
291{
292    int hds = 0;
293    int unit = 0x80;		/* IDE HDD */
294    u_int addr = 0x55d;
295
296    while (unit < 0xa7) {
297	if (*(u_char *)PTOV(addr) & (1 << (unit & 0x0f)))
298	    if (hds++ == bunit)
299		break;
300
301	if (unit >= 0xA0) {
302	    int media = ((unsigned *)PTOV(0x460))[unit & 0x0F] & 0x1F;
303
304	    if (media == 7 && hds++ == bunit)	/* SCSI MO */
305		return(0xFFFE0820); /* C:65535 H:8 S:32 */
306	}
307	if (++unit == 0x84) {
308	    unit = 0xA0;	/* SCSI HDD */
309	    addr = 0x482;
310	}
311    }
312    if (unit == 0xa7)
313	return 0x4F020F;	/* 1200KB FD C:80 H:2 S:15 */
314    v86.addr = 0x1b;
315    v86.eax = 0x8400 | unit;
316    v86int();
317    if (v86.efl & 0x1)
318	return 0x4F020F;	/* 1200KB FD C:80 H:2 S:15 */
319    return ((v86.ecx & 0xffff) << 16) | (v86.edx & 0xffff);
320}
321#endif
322
323static int
324check_slice(void)
325{
326    struct pc98_partition *dp;
327    char *sec;
328    unsigned i, cyl;
329
330    sec = dmadat->secbuf;
331    cyl = *(uint16_t *)PTOV(ARGS);
332    set_dsk();
333
334    if (dsk.type == TYPE_FD)
335	return (WHOLE_DISK_SLICE);
336    if (drvread(sec, DOSBBSECTOR + 1))
337	return (WHOLE_DISK_SLICE);	/* Read error */
338    dp = (void *)(sec + DOSPARTOFF);
339    for (i = 0; i < NDOSPART; i++) {
340	if (dp[i].dp_mid == DOSMID_386BSD) {
341	    if (dp[i].dp_scyl <= cyl && cyl <= dp[i].dp_ecyl)
342		return (BASE_SLICE + i);
343	}
344    }
345
346    return (WHOLE_DISK_SLICE);
347}
348
349int
350main(void)
351{
352#ifdef GET_BIOSGEOM
353    int i;
354#endif
355    uint8_t autoboot;
356    ino_t ino;
357
358    dmadat = (void *)(roundup2(__base + (int32_t)&_end, 0x10000) - __base);
359    v86.ctl = V86_FLAGS;
360    v86.efl = PSL_RESERVED_DEFAULT | PSL_I;
361    dsk.daua = *(uint8_t *)PTOV(0x584);
362    dsk.disk = dsk.daua & DRV_DISK;
363    dsk.unit = dsk.daua & DRV_UNIT;
364    if (dsk.disk == 0x80)
365        dsk.type = TYPE_AD;
366    else if (dsk.disk == 0xa0)
367        dsk.type = TYPE_DA;
368    else /* if (dsk.disk == 0x30 || dsk.disk == 0x90) */
369        dsk.type = TYPE_FD;
370    dsk.slice = check_slice();
371#ifdef GET_BIOSGEOM
372    for (i = 0; i < N_BIOS_GEOM; i++)
373	bootinfo.bi_bios_geom[i] = bd_getbigeom(i);
374#endif
375    bootinfo.bi_version = BOOTINFO_VERSION;
376    bootinfo.bi_size = sizeof(bootinfo);
377
378    /* Process configuration file */
379
380    autoboot = 1;
381
382    if ((ino = lookup(PATH_CONFIG)))
383	fsread(ino, cmd, sizeof(cmd));
384
385    if (*cmd) {
386	memcpy(cmddup, cmd, sizeof(cmd));
387	if (parse())
388	    autoboot = 0;
389	if (!OPT_CHECK(RBX_QUIET))
390	    printf("%s: %s", PATH_CONFIG, cmddup);
391	/* Do not process this command twice */
392	*cmd = 0;
393    }
394
395    /*
396     * Try to exec stage 3 boot loader. If interrupted by a keypress,
397     * or in case of failure, try to load a kernel directly instead.
398     */
399
400    if (autoboot && !kname) {
401	kname = PATH_BOOT3;
402	if (!keyhit(3*SECOND)) {
403	    load();
404	    kname = PATH_KERNEL;
405	}
406    }
407
408    /* Present the user with the boot2 prompt. */
409
410    for (;;) {
411	if (!autoboot || !OPT_CHECK(RBX_QUIET))
412	    printf("\nFreeBSD/pc98 boot\n"
413		   "Default: %u:%s(%u,%c)%s\n"
414		   "boot: ",
415		   dsk.unit, dev_nm[dsk.type], dsk.unit,
416		   'a' + dsk.part, kname);
417	if (ioctrl & IO_SERIAL)
418	    sio_flush();
419	if (!autoboot || keyhit(3*SECOND))
420	    getstr();
421	else if (!autoboot || !OPT_CHECK(RBX_QUIET))
422	    putchar('\n');
423	autoboot = 0;
424	if (parse())
425	    putchar('\a');
426	else
427	    load();
428    }
429}
430
431/* XXX - Needed for btxld to link the boot2 binary; do not remove. */
432void
433exit(int x)
434{
435}
436
437static void
438load(void)
439{
440    union {
441	struct exec ex;
442	Elf32_Ehdr eh;
443    } hdr;
444    static Elf32_Phdr ep[2];
445    static Elf32_Shdr es[2];
446    caddr_t p;
447    ino_t ino;
448    uint32_t addr, x;
449    int i, j;
450    uint8_t fmt;
451
452    if (!(ino = lookup(kname))) {
453	if (!ls)
454	    printf("No %s\n", kname);
455	return;
456    }
457    if (xfsread(ino, &hdr, sizeof(hdr)))
458	return;
459    if (N_GETMAGIC(hdr.ex) == ZMAGIC)
460	fmt = 0;
461    else if (IS_ELF(hdr.eh))
462	fmt = 1;
463    else {
464	printf("Invalid %s\n", "format");
465	return;
466    }
467    if (fmt == 0) {
468	addr = hdr.ex.a_entry & 0xffffff;
469	p = PTOV(addr);
470	fs_off = PAGE_SIZE;
471	if (xfsread(ino, p, hdr.ex.a_text))
472	    return;
473	p += roundup2(hdr.ex.a_text, PAGE_SIZE);
474	if (xfsread(ino, p, hdr.ex.a_data))
475	    return;
476    } else {
477	fs_off = hdr.eh.e_phoff;
478	for (j = i = 0; i < hdr.eh.e_phnum && j < 2; i++) {
479	    if (xfsread(ino, ep + j, sizeof(ep[0])))
480		return;
481	    if (ep[j].p_type == PT_LOAD)
482		j++;
483	}
484	for (i = 0; i < 2; i++) {
485	    p = PTOV(ep[i].p_paddr & 0xffffff);
486	    fs_off = ep[i].p_offset;
487	    if (xfsread(ino, p, ep[i].p_filesz))
488		return;
489	}
490	p += roundup2(ep[1].p_memsz, PAGE_SIZE);
491	bootinfo.bi_symtab = VTOP(p);
492	if (hdr.eh.e_shnum == hdr.eh.e_shstrndx + 3) {
493	    fs_off = hdr.eh.e_shoff + sizeof(es[0]) *
494		(hdr.eh.e_shstrndx + 1);
495	    if (xfsread(ino, &es, sizeof(es)))
496		return;
497	    for (i = 0; i < 2; i++) {
498		*(Elf32_Word *)p = es[i].sh_size;
499		p += sizeof(es[i].sh_size);
500		fs_off = es[i].sh_offset;
501		if (xfsread(ino, p, es[i].sh_size))
502		    return;
503		p += es[i].sh_size;
504	    }
505	}
506	addr = hdr.eh.e_entry & 0xffffff;
507	bootinfo.bi_esymtab = VTOP(p);
508    }
509    bootinfo.bi_kernelname = VTOP(kname);
510    bootinfo.bi_bios_dev = dsk.daua;
511    __exec((caddr_t)addr, RB_BOOTINFO | (opts & RBX_MASK),
512	   MAKEBOOTDEV(dev_maj[dsk.type], dsk.slice, dsk.unit, dsk.part),
513	   0, 0, 0, VTOP(&bootinfo));
514}
515
516static int
517parse()
518{
519    char *arg = cmd;
520    char *ep, *p, *q;
521    const char *cp;
522    unsigned int drv;
523    int c, i, j;
524
525    while ((c = *arg++)) {
526	if (c == ' ' || c == '\t' || c == '\n')
527	    continue;
528	for (p = arg; *p && *p != '\n' && *p != ' ' && *p != '\t'; p++);
529	ep = p;
530	if (*p)
531	    *p++ = 0;
532	if (c == '-') {
533	    while ((c = *arg++)) {
534		if (c == 'P') {
535		    if (*(uint8_t *)PTOV(0x481) & 0x48) {
536			cp = "yes";
537		    } else {
538			opts |= OPT_SET(RBX_DUAL) | OPT_SET(RBX_SERIAL);
539			cp = "no";
540		    }
541		    printf("Keyboard: %s\n", cp);
542		    continue;
543		} else if (c == 'S') {
544		    j = 0;
545		    while ((unsigned int)(i = *arg++ - '0') <= 9)
546			j = j * 10 + i;
547		    if (j > 0 && i == -'0') {
548			comspeed = j;
549			break;
550		    }
551		    /* Fall through to error below ('S' not in optstr[]). */
552		}
553		for (i = 0; c != optstr[i]; i++)
554		    if (i == NOPT - 1)
555			return -1;
556		opts ^= OPT_SET(flags[i]);
557	    }
558	    ioctrl = OPT_CHECK(RBX_DUAL) ? (IO_SERIAL|IO_KEYBOARD) :
559		     OPT_CHECK(RBX_SERIAL) ? IO_SERIAL : IO_KEYBOARD;
560	    if (ioctrl & IO_SERIAL)
561	        sio_init(115200 / comspeed);
562	} else {
563	    for (q = arg--; *q && *q != '('; q++);
564	    if (*q) {
565		drv = -1;
566		if (arg[1] == ':') {
567		    drv = *arg - '0';
568		    if (drv > 9)
569			return (-1);
570		    arg += 2;
571		}
572		if (q - arg != 2)
573		    return -1;
574		for (i = 0; arg[0] != dev_nm[i][0] ||
575			    arg[1] != dev_nm[i][1]; i++)
576		    if (i == NDEV - 1)
577			return -1;
578		dsk.type = i;
579		arg += 3;
580		dsk.unit = *arg - '0';
581		if (arg[1] != ',' || dsk.unit > 9)
582		    return -1;
583		arg += 2;
584		dsk.slice = WHOLE_DISK_SLICE;
585		if (arg[1] == ',') {
586		    dsk.slice = *arg - '0' + 1;
587		    if (dsk.slice > NDOSPART + 1)
588			return -1;
589		    arg += 2;
590		}
591		if (arg[1] != ')')
592		    return -1;
593		dsk.part = *arg - 'a';
594		if (dsk.part > 7)
595		    return (-1);
596		arg += 2;
597		if (drv == -1)
598		    drv = dsk.unit;
599		dsk.disk = dev_daua[dsk.type];
600		dsk.daua = dsk.disk | dsk.unit;
601		dsk_meta = 0;
602	    }
603            kname = arg;
604	}
605	arg = p;
606    }
607    return 0;
608}
609
610static int
611dskread(void *buf, unsigned lba, unsigned nblk)
612{
613    struct pc98_partition *dp;
614    struct disklabel *d;
615    char *sec;
616    unsigned sl, i;
617    u_char *p;
618
619    if (!dsk_meta) {
620	sec = dmadat->secbuf;
621	set_dsk();
622	if (dsk.type == TYPE_FD)
623	    goto unsliced;
624	if (drvread(sec, DOSBBSECTOR + 1))
625	    return -1;
626	dp = (void *)(sec + DOSPARTOFF);
627	sl = dsk.slice;
628	if (sl < BASE_SLICE) {
629	    for (i = 0; i < NDOSPART; i++)
630		if (dp[i].dp_mid == DOSMID_386BSD) {
631		    sl = BASE_SLICE + i;
632		    break;
633		}
634	    dsk.slice = sl;
635	}
636	if (sl != WHOLE_DISK_SLICE) {
637	    dp += sl - BASE_SLICE;
638	    if (dp->dp_mid != DOSMID_386BSD) {
639		printf("Invalid %s\n", "slice");
640		return -1;
641	    }
642	    dsk.start = dp->dp_scyl * dsk.head * dsk.sec +
643		dp->dp_shd * dsk.sec + dp->dp_ssect;
644	}
645	if (drvread(sec, dsk.start + LABELSECTOR))
646		return -1;
647	d = (void *)(sec + LABELOFFSET);
648	if (d->d_magic != DISKMAGIC || d->d_magic2 != DISKMAGIC) {
649	    if (dsk.part != RAW_PART) {
650		printf("Invalid %s\n", "label");
651		return -1;
652	    }
653	} else {
654	    if (dsk.part >= d->d_npartitions ||
655		!d->d_partitions[dsk.part].p_size) {
656		printf("Invalid %s\n", "partition");
657		return -1;
658	    }
659	    dsk.start += d->d_partitions[dsk.part].p_offset;
660	    dsk.start -= d->d_partitions[RAW_PART].p_offset;
661	}
662    unsliced: ;
663    }
664    for (p = buf; nblk; p += 512, lba++, nblk--) {
665	if ((i = drvread(p, dsk.start + lba)))
666	    return i;
667    }
668    return 0;
669}
670
671static void
672printf(const char *fmt,...)
673{
674    va_list ap;
675    char buf[10];
676    char *s;
677    unsigned u;
678    int c;
679
680    va_start(ap, fmt);
681    while ((c = *fmt++)) {
682	if (c == '%') {
683	    c = *fmt++;
684	    switch (c) {
685	    case 'c':
686		putchar(va_arg(ap, int));
687		continue;
688	    case 's':
689		for (s = va_arg(ap, char *); *s; s++)
690		    putchar(*s);
691		continue;
692	    case 'u':
693		u = va_arg(ap, unsigned);
694		s = buf;
695		do
696		    *s++ = '0' + u % 10U;
697		while (u /= 10U);
698		while (--s >= buf)
699		    putchar(*s);
700		continue;
701	    }
702	}
703	putchar(c);
704    }
705    va_end(ap);
706    return;
707}
708
709static void
710putchar(int c)
711{
712    if (c == '\n')
713	xputc('\r');
714    xputc(c);
715}
716
717static int
718drvread(void *buf, unsigned lba)
719{
720    static unsigned c = 0x2d5c7c2f;
721    unsigned bpc, x, cyl, head, sec;
722
723    bpc = dsk.sec * dsk.head;
724    cyl = lba / bpc;
725    x = lba % bpc;
726    head = x / dsk.sec;
727    sec = x % dsk.sec;
728
729    if (!OPT_CHECK(RBX_QUIET))
730	printf("%c\b", c = c << 8 | c >> 24);
731    v86.ctl = V86_ADDR | V86_CALLF | V86_FLAGS;
732    v86.addr = READORG;		/* call to read in boot1 */
733    v86.ecx = cyl;
734    v86.edx = (head << 8) | sec;
735    v86.edi = lba;
736    v86.ebx = 512;
737    v86.es = VTOPSEG(buf);
738    v86.ebp = VTOPOFF(buf);
739    v86int();
740    v86.ctl = V86_FLAGS;
741    if (V86_CY(v86.efl)) {
742	printf("error %u c/h/s %u/%u/%u lba %u\n", v86.eax >> 8 & 0xff,
743	       cyl, head, sec, lba);
744	return -1;
745    }
746    return 0;
747}
748
749static inline void
750delay(void)
751{
752    int i;
753
754    i = 800;
755    do {
756	outb(0x5f, 0);	/* about 600ns */
757    } while (--i >= 0);
758}
759
760static int
761keyhit(unsigned sec)
762{
763    unsigned i;
764
765    if (OPT_CHECK(RBX_NOINTR))
766	return 0;
767    for (i = 0; i < sec * 1000; i++) {
768	if (xgetc(1))
769	    return 1;
770	delay();
771    }
772    return 0;
773}
774
775static int
776xputc(int c)
777{
778    if (ioctrl & IO_KEYBOARD)
779	putc(c);
780    if (ioctrl & IO_SERIAL)
781	sio_putc(c);
782    return c;
783}
784
785static int
786xgetc(int fn)
787{
788    if (OPT_CHECK(RBX_NOINTR))
789	return 0;
790    for (;;) {
791	if (ioctrl & IO_KEYBOARD && getc(1))
792	    return fn ? 1 : getc(0);
793	if (ioctrl & IO_SERIAL && sio_ischar())
794	    return fn ? 1 : sio_getc();
795	if (fn)
796	    return 0;
797    }
798}
799
800static int
801getc(int fn)
802{
803    v86.addr = 0x18;
804    v86.eax = fn << 8;
805    v86int();
806    if (fn)
807	return (v86.ebx >> 8) & 0x01;
808    else
809	return v86.eax & 0xff;
810}
811