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freebsd-skq/sys/boot/i386/libi386/biosdisk.c
jhb 5690dee266 If a transfer to or from a floppy disk crosses a 64k boundary, we have to 
use a bounce buffer for the actual transfer to avoid crossing a 64k
boundary.  To do this, we malloc a buffer twice as big as we need and then
find an aligned block within that buffer to do the transfer.  The check
to see which part of the block we use used the wrong variable for part of
the condition meaning that in certain edge cases we would ask the BIOS to
cross a 64k boundary.  The BIOS request would then fail resulting in file
transfers that just magically fail in the middle without any apparent
reason.  Specifically, my tests for the splitfs boot floppies managed to
trigger this edge case.

MFC after:	1 week
X-MFC-info:	along with fixes to libstand filesystems
2004-01-21 23:22:29 +00:00

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/*-
* Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* BIOS disk device handling.
*
* Ideas and algorithms from:
*
* - NetBSD libi386/biosdisk.c
* - FreeBSD biosboot/disk.c
*
*/
#include <stand.h>
#include <sys/disklabel.h>
#include <sys/diskmbr.h>
#include <machine/bootinfo.h>
#include <stdarg.h>
#include <bootstrap.h>
#include <btxv86.h>
#include "libi386.h"
#define BIOS_NUMDRIVES 0x475
#define BIOSDISK_SECSIZE 512
#define BUFSIZE (1 * BIOSDISK_SECSIZE)
#define MAXBDDEV MAXDEV
#define DT_ATAPI 0x10 /* disk type for ATAPI floppies */
#define WDMAJOR 0 /* major numbers for devices we frontend for */
#define WFDMAJOR 1
#define FDMAJOR 2
#define DAMAJOR 4
#ifdef DISK_DEBUG
# define DEBUG(fmt, args...) printf("%s: " fmt "\n" , __func__ , ## args)
#else
# define DEBUG(fmt, args...)
#endif
struct open_disk {
int od_dkunit; /* disk unit number */
int od_unit; /* BIOS unit number */
int od_cyl; /* BIOS geometry */
int od_hds;
int od_sec;
int od_boff; /* block offset from beginning of BIOS disk */
int od_flags;
#define BD_MODEINT13 0x0000
#define BD_MODEEDD1 0x0001
#define BD_MODEEDD3 0x0002
#define BD_MODEMASK 0x0003
#define BD_FLOPPY 0x0004
#define BD_LABELOK 0x0008
#define BD_PARTTABOK 0x0010
struct disklabel od_disklabel;
int od_nslices; /* slice count */
struct dos_partition od_slicetab[NEXTDOSPART];
};
/*
* List of BIOS devices, translation from disk unit number to
* BIOS unit number.
*/
static struct bdinfo
{
int bd_unit; /* BIOS unit number */
int bd_flags;
int bd_type; /* BIOS 'drive type' (floppy only) */
} bdinfo [MAXBDDEV];
static int nbdinfo = 0;
static int bd_getgeom(struct open_disk *od);
static int bd_read(struct open_disk *od, daddr_t dblk, int blks,
caddr_t dest);
static int bd_write(struct open_disk *od, daddr_t dblk, int blks,
caddr_t dest);
static int bd_int13probe(struct bdinfo *bd);
static void bd_printslice(struct open_disk *od, struct dos_partition *dp,
char *prefix, int verbose);
static void bd_printbsdslice(struct open_disk *od, daddr_t offset,
char *prefix, int verbose);
static int bd_init(void);
static int bd_strategy(void *devdata, int flag, daddr_t dblk,
size_t size, char *buf, size_t *rsize);
static int bd_realstrategy(void *devdata, int flag, daddr_t dblk,
size_t size, char *buf, size_t *rsize);
static int bd_open(struct open_file *f, ...);
static int bd_close(struct open_file *f);
static void bd_print(int verbose);
struct devsw biosdisk = {
"disk",
DEVT_DISK,
bd_init,
bd_strategy,
bd_open,
bd_close,
noioctl,
bd_print,
NULL
};
static int bd_opendisk(struct open_disk **odp, struct i386_devdesc *dev);
static void bd_closedisk(struct open_disk *od);
static int bd_bestslice(struct open_disk *od);
static void bd_checkextended(struct open_disk *od, int slicenum);
/*
* Translate between BIOS device numbers and our private unit numbers.
*/
int
bd_bios2unit(int biosdev)
{
int i;
DEBUG("looking for bios device 0x%x", biosdev);
for (i = 0; i < nbdinfo; i++) {
DEBUG("bd unit %d is BIOS device 0x%x", i, bdinfo[i].bd_unit);
if (bdinfo[i].bd_unit == biosdev)
return(i);
}
return(-1);
}
int
bd_unit2bios(int unit)
{
if ((unit >= 0) && (unit < nbdinfo))
return(bdinfo[unit].bd_unit);
return(-1);
}
/*
* Quiz the BIOS for disk devices, save a little info about them.
*/
static int
bd_init(void)
{
int base, unit, nfd = 0;
/* sequence 0, 0x80 */
for (base = 0; base <= 0x80; base += 0x80) {
for (unit = base; (nbdinfo < MAXBDDEV); unit++) {
/* check the BIOS equipment list for number of fixed disks */
if((base == 0x80) &&
(nfd >= *(unsigned char *)PTOV(BIOS_NUMDRIVES)))
break;
bdinfo[nbdinfo].bd_unit = unit;
bdinfo[nbdinfo].bd_flags = (unit < 0x80) ? BD_FLOPPY : 0;
if (!bd_int13probe(&bdinfo[nbdinfo]))
break;
/* XXX we need "disk aliases" to make this simpler */
printf("BIOS drive %c: is disk%d\n",
(unit < 0x80) ? ('A' + unit) : ('C' + unit - 0x80), nbdinfo);
nbdinfo++;
if (base == 0x80)
nfd++;
}
}
return(0);
}
/*
* Try to detect a device supported by the legacy int13 BIOS
*/
static int
bd_int13probe(struct bdinfo *bd)
{
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0x800;
v86.edx = bd->bd_unit;
v86int();
if (!(v86.efl & 0x1) && /* carry clear */
((v86.edx & 0xff) > ((unsigned)bd->bd_unit & 0x7f))) { /* unit # OK */
bd->bd_flags |= BD_MODEINT13;
bd->bd_type = v86.ebx & 0xff;
/* Determine if we can use EDD with this device. */
v86.eax = 0x4100;
v86.edx = bd->bd_unit;
v86.ebx = 0x55aa;
v86int();
if (!(v86.efl & 0x1) && /* carry clear */
((v86.ebx & 0xffff) == 0xaa55) && /* signature */
(v86.ecx & 0x1)) { /* packets mode ok */
bd->bd_flags |= BD_MODEEDD1;
if((v86.eax & 0xff00) > 0x300)
bd->bd_flags |= BD_MODEEDD3;
}
return(1);
}
return(0);
}
/*
* Print information about disks
*/
static void
bd_print(int verbose)
{
int i, j;
char line[80];
struct i386_devdesc dev;
struct open_disk *od;
struct dos_partition *dptr;
for (i = 0; i < nbdinfo; i++) {
sprintf(line, " disk%d: BIOS drive %c:\n", i,
(bdinfo[i].bd_unit < 0x80) ? ('A' + bdinfo[i].bd_unit) : ('C' + bdinfo[i].bd_unit - 0x80));
pager_output(line);
/* try to open the whole disk */
dev.d_kind.biosdisk.unit = i;
dev.d_kind.biosdisk.slice = -1;
dev.d_kind.biosdisk.partition = -1;
if (!bd_opendisk(&od, &dev)) {
/* Do we have a partition table? */
if (od->od_flags & BD_PARTTABOK) {
dptr = &od->od_slicetab[0];
/* Check for a "dedicated" disk */
if ((dptr[3].dp_typ == DOSPTYP_386BSD) &&
(dptr[3].dp_start == 0) &&
(dptr[3].dp_size == 50000)) {
sprintf(line, " disk%d", i);
bd_printbsdslice(od, 0, line, verbose);
} else {
for (j = 0; j < od->od_nslices; j++) {
sprintf(line, " disk%ds%d", i, j + 1);
bd_printslice(od, &dptr[j], line, verbose);
}
}
}
bd_closedisk(od);
}
}
}
/*
* Print information about slices on a disk. For the size calculations we
* assume a 512 byte sector.
*/
static void
bd_printslice(struct open_disk *od, struct dos_partition *dp, char *prefix,
int verbose)
{
char line[80];
switch (dp->dp_typ) {
case DOSPTYP_386BSD:
bd_printbsdslice(od, (daddr_t)dp->dp_start, prefix, verbose);
return;
case DOSPTYP_LINSWP:
if (verbose)
sprintf(line, "%s: Linux swap %.6dMB (%d - %d)\n",
prefix, dp->dp_size / 2048,
dp->dp_start, dp->dp_start + dp->dp_size);
else
sprintf(line, "%s: Linux swap\n", prefix);
break;
case DOSPTYP_LINUX:
/*
* XXX
* read the superblock to confirm this is an ext2fs partition?
*/
if (verbose)
sprintf(line, "%s: ext2fs %.6dMB (%d - %d)\n", prefix,
dp->dp_size / 2048, dp->dp_start,
dp->dp_start + dp->dp_size);
else
sprintf(line, "%s: ext2fs\n", prefix);
break;
case 0x00: /* unused partition */
case DOSPTYP_EXT:
return;
case 0x01:
if (verbose)
sprintf(line, "%s: FAT-12 %.6dMB (%d - %d)\n", prefix,
dp->dp_size / 2048, dp->dp_start,
dp->dp_start + dp->dp_size);
else
sprintf(line, "%s: FAT-12\n", prefix);
break;
case 0x04:
case 0x06:
case 0x0e:
if (verbose)
sprintf(line, "%s: FAT-16 %.6dMB (%d - %d)\n", prefix,
dp->dp_size / 2048, dp->dp_start,
dp->dp_start + dp->dp_size);
else
sprintf(line, "%s: FAT-16\n", prefix);
break;
case 0x0b:
case 0x0c:
if (verbose)
sprintf(line, "%s: FAT-32 %.6dMB (%d - %d)\n", prefix,
dp->dp_size / 2048, dp->dp_start,
dp->dp_start + dp->dp_size);
else
sprintf(line, "%s: FAT-32\n", prefix);
break;
default:
if (verbose)
sprintf(line, "%s: Unknown fs: 0x%x %.6dMB (%d - %d)\n",
prefix, dp->dp_typ, dp->dp_size / 2048,
dp->dp_start, dp->dp_start + dp->dp_size);
else
sprintf(line, "%s: Unknown fs: 0x%x\n", prefix,
dp->dp_typ);
}
pager_output(line);
}
/*
* Print out each valid partition in the disklabel of a FreeBSD slice.
* For size calculations, we assume a 512 byte sector size.
*/
static void
bd_printbsdslice(struct open_disk *od, daddr_t offset, char *prefix,
int verbose)
{
char line[80];
char buf[BIOSDISK_SECSIZE];
struct disklabel *lp;
int i;
/* read disklabel */
if (bd_read(od, offset + LABELSECTOR, 1, buf))
return;
lp =(struct disklabel *)(&buf[0]);
if (lp->d_magic != DISKMAGIC) {
sprintf(line, "%s: FFS bad disklabel\n", prefix);
pager_output(line);
return;
}
/* Print partitions */
for (i = 0; i < lp->d_npartitions; i++) {
/*
* For each partition, make sure we know what type of fs it is. If
* not, then skip it. However, since floppies often have bogus
* fstypes, print the 'a' partition on a floppy even if it is marked
* unused.
*/
if ((lp->d_partitions[i].p_fstype == FS_BSDFFS) ||
(lp->d_partitions[i].p_fstype == FS_SWAP) ||
(lp->d_partitions[i].p_fstype == FS_VINUM) ||
((lp->d_partitions[i].p_fstype == FS_UNUSED) &&
(od->od_flags & BD_FLOPPY) && (i == 0))) {
/* Only print out statistics in verbose mode */
if (verbose)
sprintf(line, " %s%c: %s %.6dMB (%d - %d)\n", prefix, 'a' + i,
(lp->d_partitions[i].p_fstype == FS_SWAP) ? "swap" :
(lp->d_partitions[i].p_fstype == FS_VINUM) ? "vinum" :
"FFS",
lp->d_partitions[i].p_size / 2048,
lp->d_partitions[i].p_offset,
lp->d_partitions[i].p_offset + lp->d_partitions[i].p_size);
else
sprintf(line, " %s%c: %s\n", prefix, 'a' + i,
(lp->d_partitions[i].p_fstype == FS_SWAP) ? "swap" :
(lp->d_partitions[i].p_fstype == FS_VINUM) ? "vinum" :
"FFS");
pager_output(line);
}
}
}
/*
* Attempt to open the disk described by (dev) for use by (f).
*
* Note that the philosophy here is "give them exactly what
* they ask for". This is necessary because being too "smart"
* about what the user might want leads to complications.
* (eg. given no slice or partition value, with a disk that is
* sliced - are they after the first BSD slice, or the DOS
* slice before it?)
*/
static int
bd_open(struct open_file *f, ...)
{
va_list ap;
struct i386_devdesc *dev;
struct open_disk *od;
int error;
va_start(ap, f);
dev = va_arg(ap, struct i386_devdesc *);
va_end(ap);
if ((error = bd_opendisk(&od, dev)))
return(error);
/*
* Save our context
*/
((struct i386_devdesc *)(f->f_devdata))->d_kind.biosdisk.data = od;
DEBUG("open_disk %p, partition at 0x%x", od, od->od_boff);
return(0);
}
static int
bd_opendisk(struct open_disk **odp, struct i386_devdesc *dev)
{
struct dos_partition *dptr;
struct disklabel *lp;
struct open_disk *od;
int sector, slice, i;
int error;
char buf[BUFSIZE];
if (dev->d_kind.biosdisk.unit >= nbdinfo) {
DEBUG("attempt to open nonexistent disk");
return(ENXIO);
}
od = (struct open_disk *)malloc(sizeof(struct open_disk));
if (!od) {
DEBUG("no memory");
return (ENOMEM);
}
/* Look up BIOS unit number, intialise open_disk structure */
od->od_dkunit = dev->d_kind.biosdisk.unit;
od->od_unit = bdinfo[od->od_dkunit].bd_unit;
od->od_flags = bdinfo[od->od_dkunit].bd_flags;
od->od_boff = 0;
od->od_nslices = 0;
error = 0;
DEBUG("open '%s', unit 0x%x slice %d partition %c",
i386_fmtdev(dev), dev->d_kind.biosdisk.unit,
dev->d_kind.biosdisk.slice, dev->d_kind.biosdisk.partition + 'a');
/* Get geometry for this open (removable device may have changed) */
if (bd_getgeom(od)) {
DEBUG("can't get geometry");
error = ENXIO;
goto out;
}
/*
* Following calculations attempt to determine the correct value
* for d->od_boff by looking for the slice and partition specified,
* or searching for reasonable defaults.
*/
/*
* Find the slice in the DOS slice table.
*/
if (bd_read(od, 0, 1, buf)) {
DEBUG("error reading MBR");
error = EIO;
goto out;
}
/*
* Check the slice table magic.
*/
if (((u_char)buf[0x1fe] != 0x55) || ((u_char)buf[0x1ff] != 0xaa)) {
/* If a slice number was explicitly supplied, this is an error */
if (dev->d_kind.biosdisk.slice > 0) {
DEBUG("no slice table/MBR (no magic)");
error = ENOENT;
goto out;
}
sector = 0;
goto unsliced; /* may be a floppy */
}
/*
* copy the partition table, then pick up any extended partitions.
*/
bcopy(buf + DOSPARTOFF, &od->od_slicetab,
sizeof(struct dos_partition) * NDOSPART);
od->od_nslices = 4; /* extended slices start here */
for (i = 0; i < NDOSPART; i++)
bd_checkextended(od, i);
od->od_flags |= BD_PARTTABOK;
dptr = &od->od_slicetab[0];
/* Is this a request for the whole disk? */
if (dev->d_kind.biosdisk.slice == -1) {
sector = 0;
goto unsliced;
}
/*
* if a slice number was supplied but not found, this is an error.
*/
if (dev->d_kind.biosdisk.slice > 0) {
slice = dev->d_kind.biosdisk.slice - 1;
if (slice >= od->od_nslices) {
DEBUG("slice %d not found", slice);
error = ENOENT;
goto out;
}
}
/*
* Check for the historically bogus MBR found on true dedicated disks
*/
if ((dptr[3].dp_typ == DOSPTYP_386BSD) &&
(dptr[3].dp_start == 0) &&
(dptr[3].dp_size == 50000)) {
sector = 0;
goto unsliced;
}
/* Try to auto-detect the best slice; this should always give a slice number */
if (dev->d_kind.biosdisk.slice == 0) {
slice = bd_bestslice(od);
if (slice == -1) {
error = ENOENT;
goto out;
}
dev->d_kind.biosdisk.slice = slice;
}
dptr = &od->od_slicetab[0];
/*
* Accept the supplied slice number unequivocally (we may be looking
* at a DOS partition).
*/
dptr += (dev->d_kind.biosdisk.slice - 1); /* we number 1-4, offsets are 0-3 */
sector = dptr->dp_start;
DEBUG("slice entry %d at %d, %d sectors", dev->d_kind.biosdisk.slice - 1, sector, dptr->dp_size);
/*
* If we are looking at a BSD slice, and the partition is < 0, assume the 'a' partition
*/
if ((dptr->dp_typ == DOSPTYP_386BSD) && (dev->d_kind.biosdisk.partition < 0))
dev->d_kind.biosdisk.partition = 0;
unsliced:
/*
* Now we have the slice offset, look for the partition in the disklabel if we have
* a partition to start with.
*
* XXX we might want to check the label checksum.
*/
if (dev->d_kind.biosdisk.partition < 0) {
od->od_boff = sector; /* no partition, must be after the slice */
DEBUG("opening raw slice");
} else {
if (bd_read(od, sector + LABELSECTOR, 1, buf)) {
DEBUG("error reading disklabel");
error = EIO;
goto out;
}
DEBUG("copy %d bytes of label from %p to %p", sizeof(struct disklabel), buf + LABELOFFSET, &od->od_disklabel);
bcopy(buf + LABELOFFSET, &od->od_disklabel, sizeof(struct disklabel));
lp = &od->od_disklabel;
od->od_flags |= BD_LABELOK;
if (lp->d_magic != DISKMAGIC) {
DEBUG("no disklabel");
error = ENOENT;
goto out;
}
if (dev->d_kind.biosdisk.partition >= lp->d_npartitions) {
DEBUG("partition '%c' exceeds partitions in table (a-'%c')",
'a' + dev->d_kind.biosdisk.partition, 'a' + lp->d_npartitions);
error = EPART;
goto out;
}
#ifdef DISK_DEBUG
/* Complain if the partition is unused unless this is a floppy. */
if ((lp->d_partitions[dev->d_kind.biosdisk.partition].p_fstype == FS_UNUSED) &&
!(od->od_flags & BD_FLOPPY))
DEBUG("warning, partition marked as unused");
#endif
od->od_boff =
lp->d_partitions[dev->d_kind.biosdisk.partition].p_offset -
lp->d_partitions[RAW_PART].p_offset +
sector;
}
out:
if (error) {
free(od);
} else {
*odp = od; /* return the open disk */
}
return(error);
}
static void
bd_checkextended(struct open_disk *od, int slicenum)
{
char buf[BIOSDISK_SECSIZE];
struct dos_partition *dp;
u_int base;
int i, start, end;
dp = &od->od_slicetab[slicenum];
start = od->od_nslices;
if (dp->dp_size == 0)
goto done;
if (dp->dp_typ != DOSPTYP_EXT)
goto done;
if (bd_read(od, (daddr_t)dp->dp_start, 1, buf))
goto done;
if (((u_char)buf[0x1fe] != 0x55) || ((u_char)buf[0x1ff] != 0xaa)) {
DEBUG("no magic in extended table");
goto done;
}
base = dp->dp_start;
dp = (struct dos_partition *)(&buf[DOSPARTOFF]);
for (i = 0; i < NDOSPART; i++, dp++) {
if (dp->dp_size == 0)
continue;
if (od->od_nslices == NEXTDOSPART)
goto done;
dp->dp_start += base;
bcopy(dp, &od->od_slicetab[od->od_nslices], sizeof(*dp));
od->od_nslices++;
}
end = od->od_nslices;
/*
* now, recursively check the slices we just added
*/
for (i = start; i < end; i++)
bd_checkextended(od, i);
done:
return;
}
/*
* Search for a slice with the following preferences:
*
* 1: Active FreeBSD slice
* 2: Non-active FreeBSD slice
* 3: Active Linux slice
* 4: non-active Linux slice
* 5: Active FAT/FAT32 slice
* 6: non-active FAT/FAT32 slice
*/
#define PREF_RAWDISK 0
#define PREF_FBSD_ACT 1
#define PREF_FBSD 2
#define PREF_LINUX_ACT 3
#define PREF_LINUX 4
#define PREF_DOS_ACT 5
#define PREF_DOS 6
#define PREF_NONE 7
/*
* slicelimit is in the range 0 .. NDOSPART
*/
static int
bd_bestslice(struct open_disk *od)
{
struct dos_partition *dp;
int pref, preflevel;
int i, prefslice;
prefslice = 0;
preflevel = PREF_NONE;
dp = &od->od_slicetab[0];
for (i = 0; i < od->od_nslices; i++, dp++) {
switch (dp->dp_typ) {
case DOSPTYP_386BSD: /* FreeBSD */
pref = dp->dp_flag & 0x80 ? PREF_FBSD_ACT : PREF_FBSD;
break;
case DOSPTYP_LINUX:
pref = dp->dp_flag & 0x80 ? PREF_LINUX_ACT : PREF_LINUX;
break;
case 0x01: /* DOS/Windows */
case 0x04:
case 0x06:
case 0x0b:
case 0x0c:
case 0x0e:
pref = dp->dp_flag & 0x80 ? PREF_DOS_ACT : PREF_DOS;
break;
default:
pref = PREF_NONE;
}
if (pref < preflevel) {
preflevel = pref;
prefslice = i + 1;
}
}
return (prefslice);
}
static int
bd_close(struct open_file *f)
{
struct open_disk *od = (struct open_disk *)(((struct i386_devdesc *)(f->f_devdata))->d_kind.biosdisk.data);
bd_closedisk(od);
return(0);
}
static void
bd_closedisk(struct open_disk *od)
{
DEBUG("open_disk %p", od);
#if 0
/* XXX is this required? (especially if disk already open...) */
if (od->od_flags & BD_FLOPPY)
delay(3000000);
#endif
free(od);
}
static int
bd_strategy(void *devdata, int rw, daddr_t dblk, size_t size, char *buf, size_t *rsize)
{
struct bcache_devdata bcd;
struct open_disk *od = (struct open_disk *)(((struct i386_devdesc *)devdata)->d_kind.biosdisk.data);
bcd.dv_strategy = bd_realstrategy;
bcd.dv_devdata = devdata;
return(bcache_strategy(&bcd, od->od_unit, rw, dblk+od->od_boff, size, buf, rsize));
}
static int
bd_realstrategy(void *devdata, int rw, daddr_t dblk, size_t size, char *buf, size_t *rsize)
{
struct open_disk *od = (struct open_disk *)(((struct i386_devdesc *)devdata)->d_kind.biosdisk.data);
int blks;
#ifdef BD_SUPPORT_FRAGS
char fragbuf[BIOSDISK_SECSIZE];
size_t fragsize;
fragsize = size % BIOSDISK_SECSIZE;
#else
if (size % BIOSDISK_SECSIZE)
panic("bd_strategy: %d bytes I/O not multiple of block size", size);
#endif
DEBUG("open_disk %p", od);
switch(rw){
case F_READ:
blks = size / BIOSDISK_SECSIZE;
DEBUG("read %d from %d to %p", blks, dblk, buf);
if (rsize)
*rsize = 0;
if (blks && bd_read(od, dblk, blks, buf)) {
DEBUG("read error");
return (EIO);
}
#ifdef BD_SUPPORT_FRAGS
DEBUG("bd_strategy: frag read %d from %d+%d to %p",
fragsize, dblk, blks, buf + (blks * BIOSDISK_SECSIZE));
if (fragsize && bd_read(od, dblk + blks, 1, fragsize)) {
DEBUG("frag read error");
return(EIO);
}
bcopy(fragbuf, buf + (blks * BIOSDISK_SECSIZE), fragsize);
#endif
if (rsize)
*rsize = size;
return (0);
break;
case F_WRITE :
blks = size / BIOSDISK_SECSIZE;
DEBUG("write %d from %d to %p", blks, dblk, buf);
if (rsize)
*rsize = 0;
if (blks && bd_write(od, dblk, blks, buf)) {
DEBUG("write error");
return (EIO);
}
#ifdef BD_SUPPORT_FRAGS
if(fragsize) {
DEBUG("Attempted to write a frag");
return (EIO);
}
#endif
if (rsize)
*rsize = size;
return (0);
default:
/* DO NOTHING */
}
return EROFS;
}
/* Max number of sectors to bounce-buffer if the request crosses a 64k boundary */
#define FLOPPY_BOUNCEBUF 18
static int
bd_read(struct open_disk *od, daddr_t dblk, int blks, caddr_t dest)
{
u_int x, bpc, cyl, hd, sec, result, resid, retry, maxfer;
caddr_t p, xp, bbuf, breg;
/* Just in case some idiot actually tries to read -1 blocks... */
if (blks < 0)
return (-1);
bpc = (od->od_sec * od->od_hds); /* blocks per cylinder */
resid = blks;
p = dest;
/* Decide whether we have to bounce */
if ((od->od_unit < 0x80) &&
((VTOP(dest) >> 16) != (VTOP(dest + blks * BIOSDISK_SECSIZE) >> 16))) {
/*
* There is a 64k physical boundary somewhere in the destination buffer, so we have
* to arrange a suitable bounce buffer. Allocate a buffer twice as large as we
* need to. Use the bottom half unless there is a break there, in which case we
* use the top half.
*/
x = min(FLOPPY_BOUNCEBUF, (unsigned)blks);
bbuf = malloc(x * 2 * BIOSDISK_SECSIZE);
if (((u_int32_t)VTOP(bbuf) & 0xffff0000) == ((u_int32_t)VTOP(bbuf + x * BIOSDISK_SECSIZE) & 0xffff0000)) {
breg = bbuf;
} else {
breg = bbuf + x * BIOSDISK_SECSIZE;
}
maxfer = x; /* limit transfers to bounce region size */
} else {
breg = bbuf = NULL;
maxfer = 0;
}
while (resid > 0) {
x = dblk;
cyl = x / bpc; /* block # / blocks per cylinder */
x %= bpc; /* block offset into cylinder */
hd = x / od->od_sec; /* offset / blocks per track */
sec = x % od->od_sec; /* offset into track */
/* play it safe and don't cross track boundaries (XXX this is probably unnecessary) */
x = min(od->od_sec - sec, resid);
if (maxfer > 0)
x = min(x, maxfer); /* fit bounce buffer */
/* where do we transfer to? */
xp = bbuf == NULL ? p : breg;
/* correct sector number for 1-based BIOS numbering */
sec++;
/* Loop retrying the operation a couple of times. The BIOS may also retry. */
for (retry = 0; retry < 3; retry++) {
/* if retrying, reset the drive */
if (retry > 0) {
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0;
v86.edx = od->od_unit;
v86int();
}
if(cyl > 1023) {
/* use EDD if the disk supports it, otherwise, return error */
if(od->od_flags & BD_MODEEDD1) {
static unsigned short packet[8];
packet[0] = 0x10;
packet[1] = x;
packet[2] = VTOPOFF(xp);
packet[3] = VTOPSEG(xp);
packet[4] = dblk & 0xffff;
packet[5] = dblk >> 16;
packet[6] = 0;
packet[7] = 0;
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0x4200;
v86.edx = od->od_unit;
v86.ds = VTOPSEG(packet);
v86.esi = VTOPOFF(packet);
v86int();
result = (v86.efl & 0x1);
if(result == 0)
break;
} else {
result = 1;
break;
}
} else {
/* Use normal CHS addressing */
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0x200 | x;
v86.ecx = ((cyl & 0xff) << 8) | ((cyl & 0x300) >> 2) | sec;
v86.edx = (hd << 8) | od->od_unit;
v86.es = VTOPSEG(xp);
v86.ebx = VTOPOFF(xp);
v86int();
result = (v86.efl & 0x1);
if (result == 0)
break;
}
}
DEBUG("%d sectors from %d/%d/%d to %p (0x%x) %s", x, cyl, hd, sec - 1, p, VTOP(p), result ? "failed" : "ok");
/* BUG here, cannot use v86 in printf because putchar uses it too */
DEBUG("ax = 0x%04x cx = 0x%04x dx = 0x%04x status 0x%x",
0x200 | x, ((cyl & 0xff) << 8) | ((cyl & 0x300) >> 2) | sec, (hd << 8) | od->od_unit, (v86.eax >> 8) & 0xff);
if (result) {
if (bbuf != NULL)
free(bbuf);
return(-1);
}
if (bbuf != NULL)
bcopy(breg, p, x * BIOSDISK_SECSIZE);
p += (x * BIOSDISK_SECSIZE);
dblk += x;
resid -= x;
}
/* hexdump(dest, (blks * BIOSDISK_SECSIZE)); */
if (bbuf != NULL)
free(bbuf);
return(0);
}
static int
bd_write(struct open_disk *od, daddr_t dblk, int blks, caddr_t dest)
{
u_int x, bpc, cyl, hd, sec, result, resid, retry, maxfer;
caddr_t p, xp, bbuf, breg;
/* Just in case some idiot actually tries to read -1 blocks... */
if (blks < 0)
return (-1);
bpc = (od->od_sec * od->od_hds); /* blocks per cylinder */
resid = blks;
p = dest;
/* Decide whether we have to bounce */
if ((od->od_unit < 0x80) &&
((VTOP(dest) >> 16) != (VTOP(dest + blks * BIOSDISK_SECSIZE) >> 16))) {
/*
* There is a 64k physical boundary somewhere in the destination buffer, so we have
* to arrange a suitable bounce buffer. Allocate a buffer twice as large as we
* need to. Use the bottom half unless there is a break there, in which case we
* use the top half.
*/
x = min(FLOPPY_BOUNCEBUF, (unsigned)blks);
bbuf = malloc(x * 2 * BIOSDISK_SECSIZE);
if (((u_int32_t)VTOP(bbuf) & 0xffff0000) == ((u_int32_t)VTOP(bbuf + x * BIOSDISK_SECSIZE) & 0xffff0000)) {
breg = bbuf;
} else {
breg = bbuf + x * BIOSDISK_SECSIZE;
}
maxfer = x; /* limit transfers to bounce region size */
} else {
breg = bbuf = NULL;
maxfer = 0;
}
while (resid > 0) {
x = dblk;
cyl = x / bpc; /* block # / blocks per cylinder */
x %= bpc; /* block offset into cylinder */
hd = x / od->od_sec; /* offset / blocks per track */
sec = x % od->od_sec; /* offset into track */
/* play it safe and don't cross track boundaries (XXX this is probably unnecessary) */
x = min(od->od_sec - sec, resid);
if (maxfer > 0)
x = min(x, maxfer); /* fit bounce buffer */
/* where do we transfer to? */
xp = bbuf == NULL ? p : breg;
/* correct sector number for 1-based BIOS numbering */
sec++;
/* Put your Data In, Put your Data out,
Put your Data In, and shake it all about
*/
if (bbuf != NULL)
bcopy(p, breg, x * BIOSDISK_SECSIZE);
p += (x * BIOSDISK_SECSIZE);
dblk += x;
resid -= x;
/* Loop retrying the operation a couple of times. The BIOS may also retry. */
for (retry = 0; retry < 3; retry++) {
/* if retrying, reset the drive */
if (retry > 0) {
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0;
v86.edx = od->od_unit;
v86int();
}
if(cyl > 1023) {
/* use EDD if the disk supports it, otherwise, return error */
if(od->od_flags & BD_MODEEDD1) {
static unsigned short packet[8];
packet[0] = 0x10;
packet[1] = x;
packet[2] = VTOPOFF(xp);
packet[3] = VTOPSEG(xp);
packet[4] = dblk & 0xffff;
packet[5] = dblk >> 16;
packet[6] = 0;
packet[7] = 0;
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
/* Should we Write with verify ?? 0x4302 ? */
v86.eax = 0x4300;
v86.edx = od->od_unit;
v86.ds = VTOPSEG(packet);
v86.esi = VTOPOFF(packet);
v86int();
result = (v86.efl & 0x1);
if(result == 0)
break;
} else {
result = 1;
break;
}
} else {
/* Use normal CHS addressing */
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0x300 | x;
v86.ecx = ((cyl & 0xff) << 8) | ((cyl & 0x300) >> 2) | sec;
v86.edx = (hd << 8) | od->od_unit;
v86.es = VTOPSEG(xp);
v86.ebx = VTOPOFF(xp);
v86int();
result = (v86.efl & 0x1);
if (result == 0)
break;
}
}
DEBUG("%d sectors from %d/%d/%d to %p (0x%x) %s", x, cyl, hd, sec - 1, p, VTOP(p), result ? "failed" : "ok");
/* BUG here, cannot use v86 in printf because putchar uses it too */
DEBUG("ax = 0x%04x cx = 0x%04x dx = 0x%04x status 0x%x",
0x200 | x, ((cyl & 0xff) << 8) | ((cyl & 0x300) >> 2) | sec, (hd << 8) | od->od_unit, (v86.eax >> 8) & 0xff);
if (result) {
if (bbuf != NULL)
free(bbuf);
return(-1);
}
}
/* hexdump(dest, (blks * BIOSDISK_SECSIZE)); */
if (bbuf != NULL)
free(bbuf);
return(0);
}
static int
bd_getgeom(struct open_disk *od)
{
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0x800;
v86.edx = od->od_unit;
v86int();
if ((v86.efl & 0x1) || /* carry set */
((v86.edx & 0xff) <= (unsigned)(od->od_unit & 0x7f))) /* unit # bad */
return(1);
/* convert max cyl # -> # of cylinders */
od->od_cyl = ((v86.ecx & 0xc0) << 2) + ((v86.ecx & 0xff00) >> 8) + 1;
/* convert max head # -> # of heads */
od->od_hds = ((v86.edx & 0xff00) >> 8) + 1;
od->od_sec = v86.ecx & 0x3f;
DEBUG("unit 0x%x geometry %d/%d/%d", od->od_unit, od->od_cyl, od->od_hds, od->od_sec);
return(0);
}
/*
* Return the BIOS geometry of a given "fixed drive" in a format
* suitable for the legacy bootinfo structure. Since the kernel is
* expecting raw int 0x13/0x8 values for N_BIOS_GEOM drives, we
* prefer to get the information directly, rather than rely on being
* able to put it together from information already maintained for
* different purposes and for a probably different number of drives.
*
* For valid drives, the geometry is expected in the format (31..0)
* "000000cc cccccccc hhhhhhhh 00ssssss"; and invalid drives are
* indicated by returning the geometry of a "1.2M" PC-format floppy
* disk. And, incidentally, what is returned is not the geometry as
* such but the highest valid cylinder, head, and sector numbers.
*/
u_int32_t
bd_getbigeom(int bunit)
{
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0x800;
v86.edx = 0x80 + bunit;
v86int();
if (v86.efl & 0x1)
return 0x4f010f;
return ((v86.ecx & 0xc0) << 18) | ((v86.ecx & 0xff00) << 8) |
(v86.edx & 0xff00) | (v86.ecx & 0x3f);
}
/*
* Return a suitable dev_t value for (dev).
*
* In the case where it looks like (dev) is a SCSI disk, we allow the number of
* IDE disks to be specified in $num_ide_disks. There should be a Better Way.
*/
int
bd_getdev(struct i386_devdesc *dev)
{
struct open_disk *od;
int biosdev;
int major;
int rootdev;
char *nip, *cp;
int unitofs = 0, i, unit;
biosdev = bd_unit2bios(dev->d_kind.biosdisk.unit);
DEBUG("unit %d BIOS device %d", dev->d_kind.biosdisk.unit, biosdev);
if (biosdev == -1) /* not a BIOS device */
return(-1);
if (bd_opendisk(&od, dev) != 0) /* oops, not a viable device */
return(-1);
if (biosdev < 0x80) {
/* floppy (or emulated floppy) or ATAPI device */
if (bdinfo[dev->d_kind.biosdisk.unit].bd_type == DT_ATAPI) {
/* is an ATAPI disk */
major = WFDMAJOR;
} else {
/* is a floppy disk */
major = FDMAJOR;
}
} else {
/* harddisk */
if ((od->od_flags & BD_LABELOK) && (od->od_disklabel.d_type == DTYPE_SCSI)) {
/* label OK, disk labelled as SCSI */
major = DAMAJOR;
/* check for unit number correction hint, now deprecated */
if ((nip = getenv("num_ide_disks")) != NULL) {
i = strtol(nip, &cp, 0);
/* check for parse error */
if ((cp != nip) && (*cp == 0))
unitofs = i;
}
} else {
/* assume an IDE disk */
major = WDMAJOR;
}
}
/* default root disk unit number */
unit = (biosdev & 0x7f) - unitofs;
/* XXX a better kludge to set the root disk unit number */
if ((nip = getenv("root_disk_unit")) != NULL) {
i = strtol(nip, &cp, 0);
/* check for parse error */
if ((cp != nip) && (*cp == 0))
unit = i;
}
rootdev = MAKEBOOTDEV(major,
(dev->d_kind.biosdisk.slice + 1) >> 4, /* XXX slices may be wrong here */
(dev->d_kind.biosdisk.slice + 1) & 0xf,
unit,
dev->d_kind.biosdisk.partition);
DEBUG("dev is 0x%x\n", rootdev);
return(rootdev);
}
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