diff options
Diffstat (limited to 'stand/i386/loader/chain.c')
| -rw-r--r-- | stand/i386/loader/chain.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/stand/i386/loader/chain.c b/stand/i386/loader/chain.c new file mode 100644 index 0000000..d6810ef --- /dev/null +++ b/stand/i386/loader/chain.c @@ -0,0 +1,134 @@ +/*- + * 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"; + return (CMD_ERROR); + } + + if (archsw.arch_readin(fd, mem, SECTOR_SIZE) != SECTOR_SIZE) { + command_errmsg = "failed to read disk"; + close(fd); + return (CMD_ERROR); + } + close(fd); + + if (*((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 = SECTOR_SIZE; + + relocator_edx = bd_unit2bios(rootdev->d_unit); + 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 */ +} |
