freebsd-skq/stand/i386/loader/chain.c
Toomas Soome cdff10360e loader: create separate lists for fd, cd and hd, merge bioscd with biosdisk
Create unified block IO implementation in BIOS version, like it is done in UEFI
side. Implement fd, disk and cd device lists, this will split floppy devices
from disks and will allow us to have consistent, predictable device naming
(modulo BIOS issues).

Differential Revision:	https://reviews.freebsd.org/D17888
2018-11-30 08:01:11 +00:00

137 lines
3.7 KiB
C

/*-
* Copyright 2015 Toomas Soome <tsoome@me.com>
* 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.
*/
/*
* Chain loader to load BIOS boot block either from MBR or PBR.
*
* Note the boot block location 0000:7c000 conflicts with loader, so we need to
* read in to temporary space and relocate on exec, when btx is stopped.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <stand.h>
#include <sys/param.h>
#include <sys/linker.h>
#include <sys/diskmbr.h>
#include "bootstrap.h"
#include "libi386/libi386.h"
#include "btxv86.h"
/*
* The MBR/VBR is located in first sector of disk/partition.
* Read 512B to temporary location and set up relocation. Then
* exec relocator.
*/
#define SECTOR_SIZE (512)
COMMAND_SET(chain, "chain", "chain load boot block from device", command_chain);
static int
command_chain(int argc, char *argv[])
{
int fd, len, size = SECTOR_SIZE;
struct stat st;
vm_offset_t mem = 0x100000;
struct i386_devdesc *rootdev;
if (argc == 1) {
command_errmsg = "no device or file name specified";
return (CMD_ERROR);
}
if (argc != 2) {
command_errmsg = "invalid trailing arguments";
return (CMD_ERROR);
}
fd = open(argv[1], O_RDONLY);
if (fd == -1) {
command_errmsg = "open failed";
return (CMD_ERROR);
}
len = strlen(argv[1]);
if (argv[1][len-1] != ':') {
if (fstat(fd, &st) == -1) {
command_errmsg = "stat failed";
close(fd);
return (CMD_ERROR);
}
size = st.st_size;
} else if (strncmp(argv[1], "disk", 4) != 0) {
command_errmsg = "can only use disk device";
close(fd);
return (CMD_ERROR);
}
i386_getdev((void **)(&rootdev), argv[1], NULL);
if (rootdev == NULL) {
command_errmsg = "can't determine root device";
close(fd);
return (CMD_ERROR);
}
if (archsw.arch_readin(fd, mem, size) != size) {
command_errmsg = "failed to read disk";
close(fd);
return (CMD_ERROR);
}
close(fd);
if (argv[1][len-1] == ':' &&
*((uint16_t *)PTOV(mem + DOSMAGICOFFSET)) != DOSMAGIC) {
command_errmsg = "wrong magic";
return (CMD_ERROR);
}
relocater_data[0].src = mem;
relocater_data[0].dest = 0x7C00;
relocater_data[0].size = size;
relocator_edx = bd_unit2bios(rootdev);
relocator_esi = relocater_size;
relocator_ds = 0;
relocator_es = 0;
relocator_fs = 0;
relocator_gs = 0;
relocator_ss = 0;
relocator_cs = 0;
relocator_sp = 0x7C00;
relocator_ip = 0x7C00;
relocator_a20_enabled = 0;
i386_copyin(relocater, 0x600, relocater_size);
dev_cleanup();
__exec((void *)0x600);
panic("exec returned");
return (CMD_ERROR); /* not reached */
}