1 /* 2 * This file and its contents are supplied under the terms of the 3 * Common Development and Distribution License ("CDDL"), version 1.0. 4 * You may only use this file in accordance with the terms of version 5 * 1.0 of the CDDL. 6 * 7 * A full copy of the text of the CDDL should have accompanied this 8 * source. A copy of the CDDL is also available via the Internet at 9 * http://www.illumos.org/license/CDDL. 10 */ 11 12 /* 13 * Copyright 2015 Toomas Soome <tsoome@me.com> 14 */ 15 16 /* 17 * Chain loader to load BIOS boot block either from MBR or PBR. 18 * 19 * Note the boot block location 0000:7c000 conflicts with loader, so we need to 20 * read in to temporary space and relocate on exec, when btx is stopped. 21 */ 22 23 #include <sys/cdefs.h> 24 #include <stand.h> 25 #include <sys/param.h> 26 #include <sys/linker.h> 27 #include <sys/diskmbr.h> 28 29 #include "bootstrap.h" 30 #include "libi386/vbe.h" 31 #include "libi386/libi386.h" 32 #include "btxv86.h" 33 34 /* 35 * The MBR/VBR is located in first sector of disk/partition. 36 * Read 512B to temporary location and set up relocation. Then 37 * exec relocator. 38 */ 39 #define SECTOR_SIZE (512) 40 41 COMMAND_SET(chain, "chain", "chain load boot block from device", command_chain); 42 43 static int 44 command_chain(int argc, char *argv[]) 45 { 46 int fd, len, size = SECTOR_SIZE; 47 struct stat st; 48 vm_offset_t mem = 0x100000; 49 struct i386_devdesc *rootdev; 50 51 if (argc == 1) { 52 command_errmsg = "no device or file name specified"; 53 return (CMD_ERROR); 54 } 55 if (argc != 2) { 56 command_errmsg = "invalid trailing arguments"; 57 return (CMD_ERROR); 58 } 59 60 fd = open(argv[1], O_RDONLY); 61 if (fd == -1) { 62 command_errmsg = "open failed"; 63 return (CMD_ERROR); 64 } 65 66 len = strlen(argv[1]); 67 if (argv[1][len-1] != ':') { 68 if (fstat(fd, &st) == -1) { 69 command_errmsg = "stat failed"; 70 close(fd); 71 return (CMD_ERROR); 72 } 73 if (size != st.st_size) { 74 command_errmsg = "invalid size"; 75 return (CMD_ERROR); 76 } 77 } else if (strncmp(argv[1], "disk", 4) != 0) { 78 command_errmsg = "can only use disk device"; 79 close(fd); 80 return (CMD_ERROR); 81 } 82 83 i386_getdev((void **)(&rootdev), argv[1], NULL); 84 if (rootdev == NULL) { 85 command_errmsg = "can't determine root device"; 86 close(fd); 87 return (CMD_ERROR); 88 } 89 90 if (archsw.arch_readin(fd, mem, size) != size) { 91 command_errmsg = "failed to read disk"; 92 close(fd); 93 return (CMD_ERROR); 94 } 95 close(fd); 96 97 /* File or device, we assume MBR or VBR boot code */ 98 if (*((uint16_t *)PTOV(mem + DOSMAGICOFFSET)) != DOSMAGIC) { 99 command_errmsg = "wrong magic"; 100 return (CMD_ERROR); 101 } 102 103 bios_set_text_mode(3); 104 relocater_data[0].src = mem; 105 relocater_data[0].dest = 0x7C00; 106 relocater_data[0].size = size; 107 108 relocator_edx = bd_unit2bios(rootdev); 109 relocator_esi = relocater_size; 110 relocator_ds = 0; 111 relocator_es = 0; 112 relocator_fs = 0; 113 relocator_gs = 0; 114 relocator_ss = 0; 115 relocator_cs = 0; 116 relocator_sp = 0x7C00; 117 relocator_ip = 0x7C00; 118 relocator_a20_enabled = 0; 119 120 i386_copyin(relocater, 0x600, relocater_size); 121 122 dev_cleanup(); 123 124 __exec((void *)0x600); 125 126 panic("exec returned"); 127 return (CMD_ERROR); /* not reached */ 128 } 129