| 1 | /*␊ |
| 2 | File added by David F. Elliott <dfe@cox.net> on 2007/06/26␊ |
| 3 | */␊ |
| 4 | ␊ |
| 5 | #include "libsaio.h"␊ |
| 6 | #include "boot.h"␊ |
| 7 | #include "bootstruct.h"␊ |
| 8 | ␊ |
| 9 | #include "mboot.h"␊ |
| 10 | ␊ |
| 11 | #define OFFSET_1MEG 0x100000␊ |
| 12 | #define BAD_BOOT_DEVICE 0xffffffff␊ |
| 13 | ␊ |
| 14 | struct multiboot_info *gMI;␊ |
| 15 | ␊ |
| 16 | #if UNUSED␊ |
| 17 | int multiboot_timeout=0;␊ |
| 18 | int multiboot_timeout_set=0;␊ |
| 19 | int multiboot_partition=0;␊ |
| 20 | int multiboot_partition_set=0;␊ |
| 21 | #endif␊ |
| 22 | // Global multiboot info, if using multiboot.␊ |
| 23 | ␊ |
| 24 | extern void continue_at_low_address(void);␊ |
| 25 | ␊ |
| 26 | // prototype hi_multiboot and keep its implementation below multiboot_to_boot␊ |
| 27 | // to ensure that it doesn't get inlined by the compiler␊ |
| 28 | // We don't want it inlined because we specifically want the stack frame␊ |
| 29 | // pointer to be as high as possible and the hi_multiboot function␊ |
| 30 | // copies multiboot_info onto its stack.␊ |
| 31 | uint32_t hi_multiboot(int multiboot_magic, struct multiboot_info *mi_orig);␊ |
| 32 | // prototype dochainload for the same reason.␊ |
| 33 | void dochainload();␊ |
| 34 | ␊ |
| 35 | ␊ |
| 36 | // This assumes that the address of the first argument to the function will␊ |
| 37 | // be exactly 4 bytes above the address of the return address.␊ |
| 38 | // It is intended to be used as an lvalue with a statement like this -= OFFSET_1MEG;␊ |
| 39 | #define RETURN_ADDRESS_USING_FIRST_ARG(arg) \␊ |
| 40 | (*(uint32_t*)((char*)&(arg) - 4))␊ |
| 41 | ␊ |
| 42 | #define FIX_RETURN_ADDRESS_USING_FIRST_ARG(arg) \␊ |
| 43 | RETURN_ADDRESS_USING_FIRST_ARG(arg) -= OFFSET_1MEG␊ |
| 44 | ␊ |
| 45 | extern void jump_to_chainbooter();␊ |
| 46 | extern unsigned char chainbootdev;␊ |
| 47 | extern unsigned char chainbootflag;␊ |
| 48 | ␊ |
| 49 | void chainLoad();␊ |
| 50 | void waitThenReload();␊ |
| 51 | ␊ |
| 52 | // Starts off in the multiboot context 1 MB high but eventually gets into low memory␊ |
| 53 | // and winds up with a bootdevice in eax which is all that boot() wants␊ |
| 54 | // This lets the stack pointer remain very high.␊ |
| 55 | // If we were to call boot directly from multiboot then the whole multiboot_info␊ |
| 56 | // would be on the stack which would possibly be using way too much stack.␊ |
| 57 | void multiboot_to_boot(int multiboot_magic, struct multiboot_info *mi_orig)␊ |
| 58 | {␊ |
| 59 | uint32_t bootdevice = hi_multiboot(multiboot_magic, mi_orig);␊ |
| 60 | if(bootdevice != BAD_BOOT_DEVICE)␊ |
| 61 | {␊ |
| 62 | // boot only returns to do a chain load.␊ |
| 63 | for(;;)␊ |
| 64 | { // NOTE: boot only uses the last byte (the drive number)␊ |
| 65 | common_boot(bootdevice);␊ |
| 66 | if(chainbootflag)␊ |
| 67 | chainLoad();␊ |
| 68 | else␊ |
| 69 | waitThenReload();␊ |
| 70 | }␊ |
| 71 | }␊ |
| 72 | // Avoid returning to high-memory address which isn't valid in the segment␊ |
| 73 | // we are now in.␊ |
| 74 | // Calling sleep() ensures the user ought to be able to use Ctrl+Alt+Del␊ |
| 75 | // because the BIOS will have interrupts on.␊ |
| 76 | for(;;)␊ |
| 77 | sleep(10);␊ |
| 78 | // NOTE: *IF* we needed to return we'd have to fix up our return address to␊ |
| 79 | // be in low memory using the same trick as below.␊ |
| 80 | // However, there doesn't seem to be any point in returning to assembly␊ |
| 81 | // particularly when the remaining code merely halts the processor.␊ |
| 82 | }␊ |
| 83 | ␊ |
| 84 | void chainLoad()␊ |
| 85 | {␊ |
| 86 | /* TODO: We ought to load the appropriate partition table, for example␊ |
| 87 | the MBR if booting a primary partition or the particular extended␊ |
| 88 | partition table if booting a logical drive. For example, the␊ |
| 89 | regular MS MBR booter will relocate itself (e.g. the MBR) from␊ |
| 90 | 0:7C00 to 0:0600 and will use SI as the offset when reading␊ |
| 91 | the partition data from itself. Thus when it jumps to the partition␊ |
| 92 | boot sector, SI will be 0x600 + 446 + i<<4 where i is the partition␊ |
| 93 | table index.␊ |
| 94 | ␊ |
| 95 | On the other hand, our code for the non-Multiboot case doesn't do␊ |
| 96 | this either, although GRUB does.␊ |
| 97 | */␊ |
| 98 | ␊ |
| 99 | const unsigned char *bootcode = (const unsigned char*)0x7c00;␊ |
| 100 | if(bootcode[0x1fe] == 0x55 && bootcode[0x1ff] == 0xaa)␊ |
| 101 | {␊ |
| 102 | printf("Calling chainbooter\n");␊ |
| 103 | jump_to_chainbooter();␊ |
| 104 | /* NORETURN */␊ |
| 105 | }␊ |
| 106 | else␊ |
| 107 | {␊ |
| 108 | printf("Bad chain boot sector magic: %02x%02x\n", bootcode[0x1fe], bootcode[0x1ff]);␊ |
| 109 | }␊ |
| 110 | }␊ |
| 111 | ␊ |
| 112 | void waitThenReload()␊ |
| 113 | {␊ |
| 114 | /* FIXME: Ctrl+Alt+Del does not work under Boot Camp */␊ |
| 115 | ␉uint8_t i = 5;␊ |
| 116 | printf("Darwin booter exited for some reason.\n");␊ |
| 117 | printf("Please reboot (Ctrl+Alt+Del) your machine.\n");␊ |
| 118 | printf("Restarting Darwin booter in %d seconds...",i);␊ |
| 119 | sleep(1);␉␊ |
| 120 | ␉while (1 < i--) {␊ |
| 121 | ␉␉printf("%d...",i);␊ |
| 122 | ␉␉sleep(1);␊ |
| 123 | ␉}␊ |
| 124 | ␉printf("0\n");␊ |
| 125 | }␊ |
| 126 | ␊ |
| 127 | // Declare boot2_sym as an opaque struct so it can't be converted to a pointer␊ |
| 128 | // i.e. ensure the idiot programmer (me) makes sure to use address-of␊ |
| 129 | // Technically it's a function but it's real mode code and we sure don't␊ |
| 130 | // want to call it under any circumstances.␊ |
| 131 | extern struct {} boot2_sym asm("boot2");␊ |
| 132 | ␊ |
| 133 | // prototype multiboot and keep its implementation below hi_multiboot to␊ |
| 134 | // ensure that it doesn't get inlined by the compiler␊ |
| 135 | static inline uint32_t multiboot(int multiboot_magic, struct multiboot_info *mi);␊ |
| 136 | ␊ |
| 137 | ␊ |
| 138 | /*!␊ |
| 139 | Returns a pointer to the first safe address we can use for stowing the multiboot info.␊ |
| 140 | This might actually be a bit pedantic because mboot.c32 and GRUB both stow the multiboot␊ |
| 141 | info in low memory meaning that the >= 128 MB location we choose is plenty high enough.␊ |
| 142 | */␊ |
| 143 | void *determine_safe_hi_addr(int multiboot_magic, struct multiboot_info *mi_orig)␊ |
| 144 | {␊ |
| 145 | // hi_addr must be at least up in 128MB+ space so it doesn't get clobbered␊ |
| 146 | void *hi_addr = (void*)PREBOOT_DATA;␊ |
| 147 | ␊ |
| 148 | // Fail if the magic isn't correct. We'll complain later.␊ |
| 149 | if(multiboot_magic != MULTIBOOT_INFO_MAGIC)␊ |
| 150 | return NULL;␊ |
| 151 | // Make sure the command-line isn't in high memory.␊ |
| 152 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊ |
| 153 | {␊ |
| 154 | char *end = mi_orig->mi_cmdline;␊ |
| 155 | if(end != NULL)␊ |
| 156 | {␊ |
| 157 | for(; *end != '\0'; ++end)␊ |
| 158 | ;␊ |
| 159 | ++end;␊ |
| 160 | if( (void*)end > hi_addr)␊ |
| 161 | hi_addr = end;␊ |
| 162 | }␊ |
| 163 | }␊ |
| 164 | // Make sure the module information isn't in high memory␊ |
| 165 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_MODS)␊ |
| 166 | {␊ |
| 167 | struct multiboot_module *modules = (void*)mi_orig->mi_mods_addr;␊ |
| 168 | uint32_t i;␊ |
| 169 | for(i=0; i < mi_orig->mi_mods_count; ++i)␊ |
| 170 | {␊ |
| 171 | // make sure the multiboot_module struct itself won't get clobbered␊ |
| 172 | void *modinfo_end = modules+i+1;␊ |
| 173 | if(modinfo_end > hi_addr)␊ |
| 174 | hi_addr = modinfo_end;␊ |
| 175 | // make sure the module itself won't get clobbered␊ |
| 176 | modinfo_end = (void*)modules[i].mm_mod_end;␊ |
| 177 | if(modinfo_end > hi_addr)␊ |
| 178 | hi_addr = modinfo_end;␊ |
| 179 | // make sure the module string doesn't get clobbered␊ |
| 180 | char *end = modules[i].mm_string;␊ |
| 181 | for(; *end != '\0'; ++end)␊ |
| 182 | ;␊ |
| 183 | ++end;␊ |
| 184 | modinfo_end = end;␊ |
| 185 | if(modinfo_end > hi_addr)␊ |
| 186 | hi_addr = modinfo_end;␊ |
| 187 | }␊ |
| 188 | }␊ |
| 189 | // TODO: Copy syms (never needed), mmap, drives, config table, loader name, apm table, VBE info␊ |
| 190 | ␊ |
| 191 | // Round up to page size␊ |
| 192 | hi_addr = (void*)(((uint32_t)hi_addr + 0xfff) & ~(uint32_t)0xfff);␊ |
| 193 | return hi_addr;␊ |
| 194 | }␊ |
| 195 | ␊ |
| 196 | /*!␊ |
| 197 | Like malloc but with a preceding input/output parameter which points to the next available␊ |
| 198 | location for data. The original value of *hi_addr is returned and *hi_addr is incremented␊ |
| 199 | by size bytes.␊ |
| 200 | */␊ |
| 201 | void * _hi_malloc(void **hi_addr, size_t size)␊ |
| 202 | {␊ |
| 203 | void *ret = *hi_addr;␊ |
| 204 | *hi_addr += size;␊ |
| 205 | return ret;␊ |
| 206 | }␊ |
| 207 | ␊ |
| 208 | /*!␊ |
| 209 | Like strdup but with a preceding input/output parameter. The original value of *hi_addr is␊ |
| 210 | returned and *hi_addr is incremented by the number of bytes necessary to complete the string␊ |
| 211 | copy including its NUL terminator.␊ |
| 212 | */␊ |
| 213 | char * _hi_strdup(void **hi_addr, char *src)␊ |
| 214 | {␊ |
| 215 | char *dstStart;␊ |
| 216 | char *dst = dstStart = *hi_addr;␊ |
| 217 | for(; *src != '\0'; ++src, ++dst, ++(*hi_addr))␊ |
| 218 | *dst = *src;␊ |
| 219 | *dst = '\0';␊ |
| 220 | ++(*hi_addr);␊ |
| 221 | return dstStart;␊ |
| 222 | }␊ |
| 223 | ␊ |
| 224 | // Convenience macros␊ |
| 225 | #define hi_malloc(size) _hi_malloc(&hi_addr, (size))␊ |
| 226 | #define hi_strdup(src) _hi_strdup(&hi_addr, (src))␊ |
| 227 | ␊ |
| 228 | /*!␊ |
| 229 | Copies the Multiboot info and any associated data (e.g. various strings and any multiboot modules)␊ |
| 230 | up to very high RAM (above 128 MB) to ensure it doesn't get clobbered by the booter.␊ |
| 231 | */␊ |
| 232 | struct multiboot_info * copyMultibootInfo(int multiboot_magic, struct multiboot_info *mi_orig)␊ |
| 233 | {␊ |
| 234 | void *hi_addr = determine_safe_hi_addr(multiboot_magic, mi_orig);␊ |
| 235 | if(hi_addr == NULL)␊ |
| 236 | return NULL;␊ |
| 237 | ␊ |
| 238 | struct multiboot_info *mi_copy = hi_malloc(sizeof(*mi_copy));␊ |
| 239 | memcpy(mi_copy, mi_orig, sizeof(*mi_copy));␊ |
| 240 | ␊ |
| 241 | // Copy the command line␊ |
| 242 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊ |
| 243 | {␊ |
| 244 | mi_copy->mi_cmdline = hi_strdup(mi_orig->mi_cmdline);␊ |
| 245 | }␊ |
| 246 | // Copy the loader name␊ |
| 247 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_LOADER_NAME)␊ |
| 248 | {␊ |
| 249 | mi_copy->mi_loader_name = hi_strdup(mi_orig->mi_loader_name);␊ |
| 250 | }␊ |
| 251 | // Copy the module info␊ |
| 252 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_MODS)␊ |
| 253 | {␊ |
| 254 | struct multiboot_module *dst_modules = hi_malloc(sizeof(*dst_modules)*mi_orig->mi_mods_count);␊ |
| 255 | struct multiboot_module *src_modules = (void*)mi_orig->mi_mods_addr;␊ |
| 256 | mi_copy->mi_mods_addr = (uint32_t)dst_modules;␊ |
| 257 | ␊ |
| 258 | // Copy all of the module info plus the actual module into high memory␊ |
| 259 | uint32_t i;␊ |
| 260 | for(i=0; i < mi_orig->mi_mods_count; ++i)␊ |
| 261 | {␊ |
| 262 | // Assume mod_end is 1 past the actual end (i.e. it is start + size, not really end (i.e. start + size - 1))␊ |
| 263 | // This is what GRUB and mboot.c32 do although the spec is unclear on this.␊ |
| 264 | uint32_t mod_length = src_modules[i].mm_mod_end - src_modules[i].mm_mod_start;␊ |
| 265 | ␊ |
| 266 | dst_modules[i].mm_mod_start = (uint32_t)hi_malloc(mod_length);␊ |
| 267 | dst_modules[i].mm_mod_end = (uint32_t)dst_modules[i].mm_mod_start + mod_length;␊ |
| 268 | memcpy((char*)dst_modules[i].mm_mod_start, (char*)src_modules[i].mm_mod_start, mod_length);␊ |
| 269 | ␊ |
| 270 | dst_modules[i].mm_string = hi_strdup(src_modules[i].mm_string);␊ |
| 271 | dst_modules[i].mm_reserved = src_modules[i].mm_reserved;␊ |
| 272 | }␊ |
| 273 | }␊ |
| 274 | // Make sure that only stuff that didn't need to be copied or that we did deep copy is indicated in the copied struct.␊ |
| 275 | mi_copy->mi_flags &= MULTIBOOT_INFO_HAS_MEMORY | MULTIBOOT_INFO_HAS_BOOT_DEVICE | MULTIBOOT_INFO_HAS_CMDLINE | MULTIBOOT_INFO_HAS_LOADER_NAME | MULTIBOOT_INFO_HAS_MODS;␊ |
| 276 | ␊ |
| 277 | return mi_copy;␊ |
| 278 | }␊ |
| 279 | ␊ |
| 280 | // When we enter, we're actually 1 MB high.␊ |
| 281 | // Fortunately, memcpy is position independent, and it's all we need␊ |
| 282 | uint32_t hi_multiboot(int multiboot_magic, struct multiboot_info *mi_orig)␊ |
| 283 | {␊ |
| 284 | // Copy the multiboot info out of the way.␊ |
| 285 | // We can't bitch about the magic yet because printf won't work␊ |
| 286 | // because it contains an absolute location of putchar which␊ |
| 287 | // contains absolute locations to other things which eventually␊ |
| 288 | // makes a BIOS call from real mode which of course won't work␊ |
| 289 | // because we're stuck in extended memory at this point.␊ |
| 290 | struct multiboot_info *mi_p = copyMultibootInfo(multiboot_magic, mi_orig);␉␊ |
| 291 | ␉␊ |
| 292 | // Get us in to low memory so we can run everything␊ |
| 293 | ␊ |
| 294 | // We cannot possibly be more than 383.5k and copying extra won't really hurt anything␊ |
| 295 | // We use the address of the assembly entrypoint to get our starting location.␊ |
| 296 | memcpy(&boot2_sym, (char*)&boot2_sym + OFFSET_1MEG, 0x5fe00 /* 383.5k */);␉␊ |
| 297 | ␉␊ |
| 298 | // This is a little assembler routine that returns to us in the correct selector␊ |
| 299 | // instead of the kernel selector we're running in now and at the correct␊ |
| 300 | // instruction pointer ( current minus 1 MB ). It does not fix our return␊ |
| 301 | // address nor does it fix the return address of our caller.␊ |
| 302 | continue_at_low_address();␊ |
| 303 | ␊ |
| 304 | // Now fix our return address.␊ |
| 305 | FIX_RETURN_ADDRESS_USING_FIRST_ARG(multiboot_magic);␊ |
| 306 | ␊ |
| 307 | // We can now do just about anything, including return to our caller correctly.␊ |
| 308 | // However, our caller must fix his return address if he wishes to return to␊ |
| 309 | // his caller and so on and so forth.␊ |
| 310 | ␊ |
| 311 | /* Zero the BSS and initialize malloc */␊ |
| 312 | initialize_runtime();␊ |
| 313 | ␊ |
| 314 | gMI = mi_p;␊ |
| 315 | ␊ |
| 316 | /* Set up a temporary bootArgs so we can call console output routines␊ |
| 317 | like printf that check the v_display. Note that we purposefully␊ |
| 318 | do not initialize anything else at this early stage.␊ |
| 319 | ␊ |
| 320 | We are reasonably sure we're already in text mode if GRUB booted us.␊ |
| 321 | This is the same assumption that initKernBootStruct makes.␊ |
| 322 | We could check the multiboot info I guess, but why bother?␊ |
| 323 | */␊ |
| 324 | boot_args temporaryBootArgsData;␊ |
| 325 | bzero(&temporaryBootArgsData, sizeof(boot_args));␊ |
| 326 | bootArgs = &temporaryBootArgsData;␊ |
| 327 | bootArgs->Video.v_display = VGA_TEXT_MODE;␊ |
| 328 | ␊ |
| 329 | ␊ |
| 330 | // Since we call multiboot ourselves, its return address will be correct.␊ |
| 331 | // That is unless it's inlined in which case it does not matter.␊ |
| 332 | uint32_t bootdevice = multiboot(multiboot_magic, mi_p);␊ |
| 333 | // We're about to exit and temporaryBootArgs will no longer be valid␊ |
| 334 | bootArgs = NULL;␊ |
| 335 | return bootdevice;␊ |
| 336 | }␊ |
| 337 | ␊ |
| 338 | // This is the meat of our implementation. It grabs the boot device from␊ |
| 339 | // the multiboot_info and returns it as is. If it fails it returns␊ |
| 340 | // BAD_BOOT_DEVICE. We can call an awful lot of libsa and libsaio but␊ |
| 341 | // we need to take care not to call anything that requires malloc because␊ |
| 342 | // it won't be initialized until boot() does it.␊ |
| 343 | static inline uint32_t multiboot(int multiboot_magic, struct multiboot_info *mi)␊ |
| 344 | {␊ |
| 345 | if(multiboot_magic != MULTIBOOT_INFO_MAGIC)␊ |
| 346 | {␊ |
| 347 | printf("Wrong Multiboot magic\n");␊ |
| 348 | sleep(2);␊ |
| 349 | return BAD_BOOT_DEVICE;␊ |
| 350 | }␊ |
| 351 | printf("Multiboot info @0x%x\n", (uint32_t)mi);␊ |
| 352 | if(mi->mi_flags & MULTIBOOT_INFO_HAS_LOADER_NAME)␊ |
| 353 | printf("Loaded by %s\n", mi->mi_loader_name);␊ |
| 354 | ␊ |
| 355 | // Multiboot puts boot device in high byte␊ |
| 356 | // Normal booter wants it in low byte␊ |
| 357 | uint32_t bootdevice = mi->mi_boot_device_drive;␊ |
| 358 | ␊ |
| 359 | //bool doSelectDevice = false;␊ |
| 360 | if(mi->mi_flags & MULTIBOOT_INFO_HAS_BOOT_DEVICE)␊ |
| 361 | {␊ |
| 362 | printf("Boot device 0x%x\n", bootdevice);␊ |
| 363 | }␊ |
| 364 | else␊ |
| 365 | {␊ |
| 366 | printf("Multiboot info does not include chosen boot device\n");␊ |
| 367 | //doSelectDevice = true;␊ |
| 368 | bootdevice = BAD_BOOT_DEVICE;␊ |
| 369 | }␊ |
| 370 | if(mi->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊ |
| 371 | {␊ |
| 372 | const char *val;␊ |
| 373 | int size;␊ |
| 374 | ␊ |
| 375 | if(getValueForBootKey(mi->mi_cmdline, "biosdev", &val, &size))␊ |
| 376 | {␊ |
| 377 | char *endptr;␊ |
| 378 | int intVal = strtol(val, &endptr, 16 /* always hex */);␊ |
| 379 | if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊ |
| 380 | {␊ |
| 381 | printf("Boot device overridden to %02x with biosdev=%s\n", intVal, val);␊ |
| 382 | bootdevice = intVal;␊ |
| 383 | //doSelectDevice = false;␊ |
| 384 | }␊ |
| 385 | //else␊ |
| 386 | // doSelectDevice = true;␊ |
| 387 | }␊ |
| 388 | #if UNUSED␉␉␊ |
| 389 | if(getValueForBootKey(mi->mi_cmdline, "timeout", &val, &size))␊ |
| 390 | {␊ |
| 391 | char *endptr;␊ |
| 392 | int intVal = strtol(val, &endptr, 0);␊ |
| 393 | if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊ |
| 394 | {␊ |
| 395 | printf("Timeout overridden to %d with timeout=%s\n", intVal, val);␊ |
| 396 | multiboot_timeout = intVal;␊ |
| 397 | multiboot_timeout_set = 1;␊ |
| 398 | }␊ |
| 399 | }␉␉␊ |
| 400 | ␉␉␊ |
| 401 | if(getValueForBootKey(mi->mi_cmdline, "partno", &val, &size))␊ |
| 402 | {␊ |
| 403 | char *endptr;␊ |
| 404 | int intVal = strtol(val, &endptr, 0);␊ |
| 405 | if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊ |
| 406 | {␊ |
| 407 | printf("Default partition overridden to %d with timeout=%s\n", intVal, val);␊ |
| 408 | multiboot_partition = intVal;␊ |
| 409 | multiboot_partition_set = 1;␊ |
| 410 | }␊ |
| 411 | }␊ |
| 412 | #endif␊ |
| 413 | }␊ |
| 414 | if(bootdevice == BAD_BOOT_DEVICE)␊ |
| 415 | sleep(2); // pause for a second before halting␊ |
| 416 | return bootdevice;␊ |
| 417 | }␊ |
| 418 | |
