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Source at commit 1066 created 12 years 10 months ago.
By meklort, Removing even more code...
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␊
8#include "mboot.h"␊
9␊
10int multiboot_timeout=0;␊
11int multiboot_timeout_set=0;␊
12int multiboot_partition=0;␊
13int multiboot_partition_set=0;␊
14␊
15// Global multiboot info, if using multiboot.␊
16struct multiboot_info *gMI;␊
17␊
18extern void continue_at_low_address(void);␊
19␊
20// prototype hi_multiboot and keep its implementation below multiboot_to_boot␊
21// to ensure that it doesn't get inlined by the compiler␊
22// We don't want it inlined because we specifically want the stack frame␊
23// pointer to be as high as possible and the hi_multiboot function␊
24// copies multiboot_info onto its stack.␊
25uint32_t hi_multiboot(int multiboot_magic, struct multiboot_info *mi_orig);␊
26// prototype dochainload for the same reason.␊
27void dochainload();␊
28␊
29#define OFFSET_1MEG 0x100000␊
30#define BAD_BOOT_DEVICE 0xffffffff␊
31␊
32// This assumes that the address of the first argument to the function will␊
33// be exactly 4 bytes above the address of the return address.␊
34// It is intended to be used as an lvalue with a statement like this -= OFFSET_1MEG;␊
35#define RETURN_ADDRESS_USING_FIRST_ARG(arg) \␊
36 (*(uint32_t*)((char*)&(arg) - 4))␊
37␊
38#define FIX_RETURN_ADDRESS_USING_FIRST_ARG(arg) \␊
39 RETURN_ADDRESS_USING_FIRST_ARG(arg) -= OFFSET_1MEG␊
40␊
41extern void jump_to_chainbooter();␊
42extern unsigned char chainbootdev;␊
43extern unsigned char chainbootflag;␊
44␊
45void chainLoad();␊
46void waitThenReload();␊
47␊
48int multibootRamdiskReadBytes( int biosdev, unsigned int blkno,␊
49 unsigned int byteoff,␊
50 unsigned int byteCount, void * buffer );␊
51int multiboot_get_ramdisk_info(int biosdev, struct driveInfo *dip);␊
52//static long multiboot_LoadExtraDrivers(FileLoadDrivers_t FileLoadDrivers_p);␊
53␊
54// Starts off in the multiboot context 1 MB high but eventually gets into low memory␊
55// and winds up with a bootdevice in eax which is all that boot() wants␊
56// This lets the stack pointer remain very high.␊
57// If we were to call boot directly from multiboot then the whole multiboot_info␊
58// would be on the stack which would possibly be using way too much stack.␊
59void multiboot_to_boot(int multiboot_magic, struct multiboot_info *mi_orig)␊
60{␊
61 uint32_t bootdevice = hi_multiboot(multiboot_magic, mi_orig);␊
62 if(bootdevice != BAD_BOOT_DEVICE)␊
63 {␊
64 // boot only returns to do a chain load.␊
65 for(;;)␊
66 { // NOTE: boot only uses the last byte (the drive number)␊
67 common_boot(bootdevice);␊
68 if(chainbootflag)␊
69 chainLoad();␊
70 else␊
71 waitThenReload();␊
72 }␊
73 }␊
74 // Avoid returning to high-memory address which isn't valid in the segment␊
75 // we are now in.␊
76 // Calling sleep() ensures the user ought to be able to use Ctrl+Alt+Del␊
77 // because the BIOS will have interrupts on.␊
78 for(;;)␊
79 sleep(10);␊
80 // NOTE: *IF* we needed to return we'd have to fix up our return address to␊
81 // be in low memory using the same trick as below.␊
82 // However, there doesn't seem to be any point in returning to assembly␊
83 // particularly when the remaining code merely halts the processor.␊
84}␊
85␊
86void chainLoad()␊
87{␊
88 /* TODO: We ought to load the appropriate partition table, for example␊
89 the MBR if booting a primary partition or the particular extended␊
90 partition table if booting a logical drive. For example, the␊
91 regular MS MBR booter will relocate itself (e.g. the MBR) from␊
92 0:7C00 to 0:0600 and will use SI as the offset when reading␊
93 the partition data from itself. Thus when it jumps to the partition␊
94 boot sector, SI will be 0x600 + 446 + i<<4 where i is the partition␊
95 table index.␊
96 ␊
97 On the other hand, our code for the non-Multiboot case doesn't do␊
98 this either, although GRUB does.␊
99 */␊
100␊
101 const unsigned char *bootcode = (const unsigned char*)0x7c00;␊
102 if(bootcode[0x1fe] == 0x55 && bootcode[0x1ff] == 0xaa)␊
103 {␊
104 printf("Calling chainbooter\n");␊
105 jump_to_chainbooter();␊
106 /* NORETURN */␊
107 }␊
108 else␊
109 {␊
110 printf("Bad chain boot sector magic: %02x%02x\n", bootcode[0x1fe], bootcode[0x1ff]);␊
111 }␊
112}␊
113␊
114void waitThenReload()␊
115{␊
116 /* FIXME: Ctrl+Alt+Del does not work under Boot Camp */␊
117 printf("Darwin booter exited for some reason.\n");␊
118 printf("Please reboot (Ctrl+Alt+Del) your machine.\n");␊
119 printf("Restarting Darwin booter in 5 seconds...");␊
120 sleep(1);␊
121 printf("4...");␊
122 sleep(1);␊
123 printf("3...");␊
124 sleep(1);␊
125 printf("2...");␊
126 sleep(1);␊
127 printf("1...");␊
128 sleep(1);␊
129 printf("0\n");␊
130}␊
131␊
132// Declare boot2_sym as an opaque struct so it can't be converted to a pointer␊
133// i.e. ensure the idiot programmer (me) makes sure to use address-of␊
134// Technically it's a function but it's real mode code and we sure don't␊
135// want to call it under any circumstances.␊
136extern struct {} boot2_sym asm("boot2");␊
137␊
138// prototype multiboot and keep its implementation below hi_multiboot to␊
139// ensure that it doesn't get inlined by the compiler␊
140static inline uint32_t multiboot(int multiboot_magic, struct multiboot_info *mi);␊
141␊
142␊
143/*!␊
144 Returns a pointer to the first safe address we can use for stowing the multiboot info.␊
145 This might actually be a bit pedantic because mboot.c32 and GRUB both stow the multiboot␊
146 info in low memory meaning that the >= 128 MB location we choose is plenty high enough.␊
147 */␊
148void *determine_safe_hi_addr(int multiboot_magic, struct multiboot_info *mi_orig)␊
149{␊
150 // hi_addr must be at least up in 128MB+ space so it doesn't get clobbered␊
151 void *hi_addr = (void*)PREBOOT_DATA;␊
152␊
153 // Fail if the magic isn't correct. We'll complain later.␊
154 if(multiboot_magic != MULTIBOOT_INFO_MAGIC)␊
155 return NULL;␊
156 // Make sure the command-line isn't in high memory.␊
157 if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊
158 {␊
159 char *end = mi_orig->mi_cmdline;␊
160 if(end != NULL)␊
161 {␊
162 for(; *end != '\0'; ++end)␊
163 ;␊
164 ++end;␊
165 if( (void*)end > hi_addr)␊
166 hi_addr = end;␊
167 }␊
168 }␊
169 // Make sure the module information isn't in high memory␊
170 if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_MODS)␊
171 {␊
172 struct multiboot_module *modules = (void*)mi_orig->mi_mods_addr;␊
173 int i;␊
174 for(i=0; i < mi_orig->mi_mods_count; ++i)␊
175 {␊
176 // make sure the multiboot_module struct itself won't get clobbered␊
177 void *modinfo_end = modules+i+1;␊
178 if(modinfo_end > hi_addr)␊
179 hi_addr = modinfo_end;␊
180 // make sure the module itself won't get clobbered␊
181 modinfo_end = (void*)modules[i].mm_mod_end;␊
182 if(modinfo_end > hi_addr)␊
183 hi_addr = modinfo_end;␊
184 // make sure the module string doesn't get clobbered␊
185 char *end = modules[i].mm_string;␊
186 for(; *end != '\0'; ++end)␊
187 ;␊
188 ++end;␊
189 modinfo_end = end;␊
190 if(modinfo_end > hi_addr)␊
191 hi_addr = modinfo_end;␊
192 }␊
193 }␊
194 // TODO: Copy syms (never needed), mmap, drives, config table, loader name, apm table, VBE info␊
195␊
196 // Round up to page size␊
197 hi_addr = (void*)(((uint32_t)hi_addr + 0xfff) & ~(uint32_t)0xfff);␊
198 return hi_addr;␊
199}␊
200␊
201/*!␊
202 Like malloc but with a preceding input/output parameter which points to the next available␊
203 location for data. The original value of *hi_addr is returned and *hi_addr is incremented␊
204 by size bytes.␊
205 */␊
206void * _hi_malloc(void **hi_addr, size_t size)␊
207{␊
208 void *ret = *hi_addr;␊
209 *hi_addr += size;␊
210 return ret;␊
211}␊
212␊
213/*!␊
214 Like strdup but with a preceding input/output parameter. The original value of *hi_addr is␊
215 returned and *hi_addr is incremented by the number of bytes necessary to complete the string␊
216 copy including its NUL terminator.␊
217 */␊
218char * _hi_strdup(void **hi_addr, char *src)␊
219{␊
220 char *dstStart;␊
221 char *dst = dstStart = *hi_addr;␊
222 for(; *src != '\0'; ++src, ++dst, ++(*hi_addr))␊
223 *dst = *src;␊
224 *dst = '\0';␊
225 ++(*hi_addr);␊
226 return dstStart;␊
227}␊
228␊
229// Convenience macros␊
230#define hi_malloc(size) _hi_malloc(&hi_addr, (size))␊
231#define hi_strdup(src) _hi_strdup(&hi_addr, (src))␊
232␊
233/*!␊
234 Copies the Multiboot info and any associated data (e.g. various strings and any multiboot modules)␊
235 up to very high RAM (above 128 MB) to ensure it doesn't get clobbered by the booter.␊
236 */␊
237struct multiboot_info * copyMultibootInfo(int multiboot_magic, struct multiboot_info *mi_orig)␊
238{␊
239 void *hi_addr = determine_safe_hi_addr(multiboot_magic, mi_orig);␊
240 if(hi_addr == NULL)␊
241 return NULL;␊
242␊
243 struct multiboot_info *mi_copy = hi_malloc(sizeof(*mi_copy));␊
244 memcpy(mi_copy, mi_orig, sizeof(*mi_copy));␊
245 ␊
246 // Copy the command line␊
247 if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊
248 {␊
249 mi_copy->mi_cmdline = hi_strdup(mi_orig->mi_cmdline);␊
250 }␊
251 // Copy the loader name␊
252 if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_LOADER_NAME)␊
253 {␊
254 mi_copy->mi_loader_name = hi_strdup(mi_orig->mi_loader_name);␊
255 }␊
256 // Copy the module info␊
257 if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_MODS)␊
258 {␊
259 struct multiboot_module *dst_modules = hi_malloc(sizeof(*dst_modules)*mi_orig->mi_mods_count);␊
260 struct multiboot_module *src_modules = (void*)mi_orig->mi_mods_addr;␊
261 mi_copy->mi_mods_addr = (uint32_t)dst_modules;␊
262␊
263 // Copy all of the module info plus the actual module into high memory␊
264 int i;␊
265 for(i=0; i < mi_orig->mi_mods_count; ++i)␊
266 {␊
267 // Assume mod_end is 1 past the actual end (i.e. it is start + size, not really end (i.e. start + size - 1))␊
268 // This is what GRUB and mboot.c32 do although the spec is unclear on this.␊
269 uint32_t mod_length = src_modules[i].mm_mod_end - src_modules[i].mm_mod_start;␊
270␊
271 dst_modules[i].mm_mod_start = (uint32_t)hi_malloc(mod_length);␊
272 dst_modules[i].mm_mod_end = (uint32_t)dst_modules[i].mm_mod_start + mod_length;␊
273 memcpy((char*)dst_modules[i].mm_mod_start, (char*)src_modules[i].mm_mod_start, mod_length);␊
274 ␊
275 dst_modules[i].mm_string = hi_strdup(src_modules[i].mm_string);␊
276 dst_modules[i].mm_reserved = src_modules[i].mm_reserved;␊
277 }␊
278 }␊
279 // Make sure that only stuff that didn't need to be copied or that we did deep copy is indicated in the copied struct.␊
280 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;␊
281␊
282 return mi_copy;␊
283}␊
284␊
285// When we enter, we're actually 1 MB high.␊
286// Fortunately, memcpy is position independent, and it's all we need␊
287uint32_t hi_multiboot(int multiboot_magic, struct multiboot_info *mi_orig)␊
288{␊
289 // Copy the multiboot info out of the way.␊
290 // We can't bitch about the magic yet because printf won't work␊
291 // because it contains an absolute location of putchar which␊
292 // contains absolute locations to other things which eventually␊
293 // makes a BIOS call from real mode which of course won't work␊
294 // because we're stuck in extended memory at this point.␊
295 struct multiboot_info *mi_p = copyMultibootInfo(multiboot_magic, mi_orig);␊
296␊
297 // Get us in to low memory so we can run everything␊
298␊
299 // We cannot possibly be more than 447k and copying extra won't really hurt anything␊
300 // We use the address of the assembly entrypoint to get our starting location.␊
301 memcpy(&boot2_sym, (char*)&boot2_sym + OFFSET_1MEG, BOOT2_MAX_LENGTH /* 447k */);␊
302␊
303 // This is a little assembler routine that returns to us in the correct selector␊
304 // instead of the kernel selector we're running in now and at the correct␊
305 // instruction pointer ( current minus 1 MB ). It does not fix our return␊
306 // address nor does it fix the return address of our caller.␊
307 continue_at_low_address();␊
308␊
309 // Now fix our return address.␊
310 FIX_RETURN_ADDRESS_USING_FIRST_ARG(multiboot_magic);␊
311␊
312 // We can now do just about anything, including return to our caller correctly.␊
313 // However, our caller must fix his return address if he wishes to return to␊
314 // his caller and so on and so forth.␊
315␊
316 /* Zero the BSS and initialize malloc */␊
317 initialize_runtime();␊
318␊
319 gMI = mi_p;␊
320␊
321 /* Set up a temporary bootArgs so we can call console output routines␊
322 like printf that check the v_display. Note that we purposefully␊
323 do not initialize anything else at this early stage.␊
324␊
325 We are reasonably sure we're already in text mode if GRUB booted us.␊
326 This is the same assumption that initKernBootStruct makes.␊
327 We could check the multiboot info I guess, but why bother?␊
328 */␊
329 boot_args temporaryBootArgsData;␊
330 bzero(&temporaryBootArgsData, sizeof(boot_args));␊
331// bootArgs = &temporaryBootArgsData;␊
332 // bootArgs->Video.v_display = VGA_TEXT_MODE;␊
333␊
334 // Install ramdisk and extra driver hooks␊
335 p_get_ramdisk_info = &multiboot_get_ramdisk_info;␊
336 p_ramdiskReadBytes = &multibootRamdiskReadBytes;␊
337 //LoadExtraDrivers_p = &multiboot_LoadExtraDrivers;␊
338␊
339 // Since we call multiboot ourselves, its return address will be correct.␊
340 // That is unless it's inlined in which case it does not matter.␊
341 uint32_t bootdevice = multiboot(multiboot_magic, mi_p);␊
342 // We're about to exit and temporaryBootArgs will no longer be valid␊
343 //bootArgs = NULL;␊
344 return bootdevice;␊
345}␊
346␊
347// This is the meat of our implementation. It grabs the boot device from␊
348// the multiboot_info and returns it as is. If it fails it returns␊
349// BAD_BOOT_DEVICE. We can call an awful lot of libsa and libsaio but␊
350// we need to take care not to call anything that requires malloc because␊
351// it won't be initialized until boot() does it.␊
352static inline uint32_t multiboot(int multiboot_magic, struct multiboot_info *mi)␊
353{␊
354 if(multiboot_magic != MULTIBOOT_INFO_MAGIC)␊
355 {␊
356 printf("Wrong Multiboot magic\n");␊
357 sleep(2);␊
358 return BAD_BOOT_DEVICE;␊
359 }␊
360 printf("Multiboot info @0x%x\n", (uint32_t)mi);␊
361 if(mi->mi_flags & MULTIBOOT_INFO_HAS_LOADER_NAME)␊
362 printf("Loaded by %s\n", mi->mi_loader_name);␊
363␊
364 // Multiboot puts boot device in high byte␊
365 // Normal booter wants it in low byte␊
366 int bootdevice = mi->mi_boot_device_drive;␊
367␊
368 bool doSelectDevice = false;␊
369 if(mi->mi_flags & MULTIBOOT_INFO_HAS_BOOT_DEVICE)␊
370 {␊
371 printf("Boot device 0x%x\n", bootdevice);␊
372 }␊
373 else␊
374 {␊
375 printf("Multiboot info does not include chosen boot device\n");␊
376 doSelectDevice = true;␊
377 bootdevice = BAD_BOOT_DEVICE;␊
378 }␊
379 if(mi->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊
380 {␊
381 const char *val;␊
382 int size;␊
383 ␊
384 if(getValueForBootKey(mi->mi_cmdline, "biosdev", &val, &size))␊
385 {␊
386 char *endptr;␊
387 int intVal = strtol(val, &endptr, 16 /* always hex */);␊
388 if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊
389 {␊
390 printf("Boot device overridden to %02x with biosdev=%s\n", intVal, val);␊
391 bootdevice = intVal;␊
392 doSelectDevice = false;␊
393 }␊
394 else␊
395 doSelectDevice = true;␊
396 }␊
397␉␉␊
398 if(getValueForBootKey(mi->mi_cmdline, "timeout", &val, &size))␊
399 {␊
400 char *endptr;␊
401 int intVal = strtol(val, &endptr, 0);␊
402 if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊
403 {␊
404 printf("Timeout overridden to %d with timeout=%s\n", intVal, val);␊
405 multiboot_timeout = intVal;␊
406 multiboot_timeout_set = 1;␊
407 }␊
408 }␉␉␊
409␉␉␊
410 if(getValueForBootKey(mi->mi_cmdline, "partno", &val, &size))␊
411 {␊
412 char *endptr;␊
413 int intVal = strtol(val, &endptr, 0);␊
414 if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊
415 {␊
416 printf("Default partition overridden to %d with timeout=%s\n", intVal, val);␊
417 multiboot_partition = intVal;␊
418 multiboot_partition_set = 1;␊
419 }␊
420 }␉␉␉␉␊
421 }␊
422␊
423 if(bootdevice == BAD_BOOT_DEVICE)␊
424 sleep(2); // pause for a second before halting␊
425 return bootdevice;␊
426}␊
427␊
428///////////////////////////////////////////////////////////////////////////␊
429// Ramdisk and extra drivers code␊
430␊
431int multibootRamdiskReadBytes( int biosdev, unsigned int blkno,␊
432 unsigned int byteoff,␊
433 unsigned int byteCount, void * buffer )␊
434{␊
435 int module_count = gMI->mi_mods_count;␊
436 struct multiboot_module *modules = (void*)gMI->mi_mods_addr;␊
437 if(biosdev < 0x100)␊
438 return -1;␊
439 if(biosdev >= (0x100 + module_count))␊
440 return -1;␊
441 struct multiboot_module *module = modules + (biosdev - 0x100);␊
442␊
443 void *p_initrd = (void*)module->mm_mod_start;␊
444 bcopy(p_initrd + blkno*512 + byteoff, buffer, byteCount);␊
445 return 0;␊
446}␊
447␊
448int multiboot_get_ramdisk_info(int biosdev, struct driveInfo *dip)␊
449{␊
450 int module_count = gMI->mi_mods_count;␊
451 struct multiboot_module *modules = (void*)gMI->mi_mods_addr;␊
452 if(biosdev < 0x100)␊
453 return -1;␊
454 if(biosdev >= (0x100 + module_count))␊
455 return -1;␊
456 struct multiboot_module *module = modules + (biosdev - 0x100);␊
457 dip->biosdev = biosdev;␊
458 dip->uses_ebios = true;␉// XXX aserebln uses_ebios isn't a boolean at all␊
459 dip->di.params.phys_sectors = (module->mm_mod_end - module->mm_mod_start + 511) / 512;␊
460 dip->valid = true;␊
461 return 0;␊
462}␊
463#if 0␊
464static long multiboot_LoadExtraDrivers(FileLoadDrivers_t FileLoadDrivers_p)␊
465{␊
466 char extensionsSpec[1024];␊
467 int ramdiskUnit;␊
468 for(ramdiskUnit = 0; ramdiskUnit < gMI->mi_mods_count; ++ramdiskUnit)␊
469 {␊
470 int partCount; // unused␊
471 BVRef ramdiskChain = diskScanBootVolumes(0x100 + ramdiskUnit, &partCount);␊
472 if(ramdiskChain == NULL)␊
473 {␊
474 verbose("Ramdisk contains no partitions\n");␊
475 continue;␊
476 }␊
477 for(; ramdiskChain != NULL; ramdiskChain = ramdiskChain->next)␊
478 {␊
479 sprintf(extensionsSpec, "rd(%d,%d)/Extra/", ramdiskUnit, ramdiskChain->part_no);␊
480 struct dirstuff *extradir = opendir(extensionsSpec);␊
481 closedir(extradir);␊
482 if(extradir != NULL)␊
483 {␊
484 int ret = FileLoadDrivers_p(extensionsSpec, 0 /* this is a kext root dir, not a kext with plugins */);␊
485 if(ret != 0)␊
486 {␊
487 verbose("FileLoadDrivers failed on a ramdisk\n");␊
488 return ret;␊
489 }␊
490 }␊
491 }␊
492 }␊
493 return 0;␊
494}␊
495#endif

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