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Source at commit 575 created 13 years 6 months ago.
By meklort, Ramdisk 10.x extension loading
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␊
15#ifdef UNUSED␊
16␊
17int multiboot_timeout=0;␊
18int multiboot_timeout_set=0;␊
19int multiboot_partition=0;␊
20int multiboot_partition_set=0;␊
21␊
22// Global multiboot info, if using multiboot.␊
23struct multiboot_info *gMI;␊
24␊
25extern void continue_at_low_address(void);␊
26␊
27// prototype hi_multiboot and keep its implementation below multiboot_to_boot␊
28// to ensure that it doesn't get inlined by the compiler␊
29// We don't want it inlined because we specifically want the stack frame␊
30// pointer to be as high as possible and the hi_multiboot function␊
31// copies multiboot_info onto its stack.␊
32uint32_t hi_multiboot(int multiboot_magic, struct multiboot_info *mi_orig);␊
33// prototype dochainload for the same reason.␊
34void dochainload();␊
35␊
36␊
37// This assumes that the address of the first argument to the function will␊
38// be exactly 4 bytes above the address of the return address.␊
39// It is intended to be used as an lvalue with a statement like this -= OFFSET_1MEG;␊
40#define RETURN_ADDRESS_USING_FIRST_ARG(arg) \␊
41 (*(uint32_t*)((char*)&(arg) - 4))␊
42␊
43#define FIX_RETURN_ADDRESS_USING_FIRST_ARG(arg) \␊
44 RETURN_ADDRESS_USING_FIRST_ARG(arg) -= OFFSET_1MEG␊
45␊
46extern void jump_to_chainbooter();␊
47extern unsigned char chainbootdev;␊
48extern unsigned char chainbootflag;␊
49␊
50void chainLoad();␊
51void waitThenReload();␊
52␊
53int multibootRamdiskReadBytes( int biosdev, unsigned int blkno,␊
54 unsigned int byteoff,␊
55 unsigned int byteCount, void * buffer );␊
56int multiboot_get_ramdisk_info(int biosdev, struct driveInfo *dip);␊
57static long multiboot_LoadExtraDrivers(FileLoadDrivers_t FileLoadDrivers_p);␊
58␊
59// Starts off in the multiboot context 1 MB high but eventually gets into low memory␊
60// and winds up with a bootdevice in eax which is all that boot() wants␊
61// This lets the stack pointer remain very high.␊
62// If we were to call boot directly from multiboot then the whole multiboot_info␊
63// would be on the stack which would possibly be using way too much stack.␊
64void multiboot_to_boot(int multiboot_magic, struct multiboot_info *mi_orig)␊
65{␊
66 uint32_t bootdevice = hi_multiboot(multiboot_magic, mi_orig);␊
67 if(bootdevice != BAD_BOOT_DEVICE)␊
68 {␊
69 // boot only returns to do a chain load.␊
70 for(;;)␊
71 { // NOTE: boot only uses the last byte (the drive number)␊
72 common_boot(bootdevice);␊
73 if(chainbootflag)␊
74 chainLoad();␊
75 else␊
76 waitThenReload();␊
77 }␊
78 }␊
79 // Avoid returning to high-memory address which isn't valid in the segment␊
80 // we are now in.␊
81 // Calling sleep() ensures the user ought to be able to use Ctrl+Alt+Del␊
82 // because the BIOS will have interrupts on.␊
83 for(;;)␊
84 sleep(10);␊
85 // NOTE: *IF* we needed to return we'd have to fix up our return address to␊
86 // be in low memory using the same trick as below.␊
87 // However, there doesn't seem to be any point in returning to assembly␊
88 // particularly when the remaining code merely halts the processor.␊
89}␊
90␊
91void chainLoad()␊
92{␊
93 /* TODO: We ought to load the appropriate partition table, for example␊
94 the MBR if booting a primary partition or the particular extended␊
95 partition table if booting a logical drive. For example, the␊
96 regular MS MBR booter will relocate itself (e.g. the MBR) from␊
97 0:7C00 to 0:0600 and will use SI as the offset when reading␊
98 the partition data from itself. Thus when it jumps to the partition␊
99 boot sector, SI will be 0x600 + 446 + i<<4 where i is the partition␊
100 table index.␊
101 ␊
102 On the other hand, our code for the non-Multiboot case doesn't do␊
103 this either, although GRUB does.␊
104 */␊
105␊
106 const unsigned char *bootcode = (const unsigned char*)0x7c00;␊
107 if(bootcode[0x1fe] == 0x55 && bootcode[0x1ff] == 0xaa)␊
108 {␊
109 printf("Calling chainbooter\n");␊
110 jump_to_chainbooter();␊
111 /* NORETURN */␊
112 }␊
113 else␊
114 {␊
115 printf("Bad chain boot sector magic: %02x%02x\n", bootcode[0x1fe], bootcode[0x1ff]);␊
116 }␊
117}␊
118␊
119void waitThenReload()␊
120{␊
121 /* FIXME: Ctrl+Alt+Del does not work under Boot Camp */␊
122 printf("Darwin booter exited for some reason.\n");␊
123 printf("Please reboot (Ctrl+Alt+Del) your machine.\n");␊
124 printf("Restarting Darwin booter in 5 seconds...");␊
125 sleep(1);␊
126 printf("4...");␊
127 sleep(1);␊
128 printf("3...");␊
129 sleep(1);␊
130 printf("2...");␊
131 sleep(1);␊
132 printf("1...");␊
133 sleep(1);␊
134 printf("0\n");␊
135}␊
136␊
137// Declare boot2_sym as an opaque struct so it can't be converted to a pointer␊
138// i.e. ensure the idiot programmer (me) makes sure to use address-of␊
139// Technically it's a function but it's real mode code and we sure don't␊
140// want to call it under any circumstances.␊
141extern struct {} boot2_sym asm("boot2");␊
142␊
143// prototype multiboot and keep its implementation below hi_multiboot to␊
144// ensure that it doesn't get inlined by the compiler␊
145static inline uint32_t multiboot(int multiboot_magic, struct multiboot_info *mi);␊
146␊
147␊
148/*!␊
149 Returns a pointer to the first safe address we can use for stowing the multiboot info.␊
150 This might actually be a bit pedantic because mboot.c32 and GRUB both stow the multiboot␊
151 info in low memory meaning that the >= 128 MB location we choose is plenty high enough.␊
152 */␊
153void *determine_safe_hi_addr(int multiboot_magic, struct multiboot_info *mi_orig)␊
154{␊
155 // hi_addr must be at least up in 128MB+ space so it doesn't get clobbered␊
156 void *hi_addr = (void*)PREBOOT_DATA;␊
157␊
158 // Fail if the magic isn't correct. We'll complain later.␊
159 if(multiboot_magic != MULTIBOOT_INFO_MAGIC)␊
160 return NULL;␊
161 // Make sure the command-line isn't in high memory.␊
162 if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊
163 {␊
164 char *end = mi_orig->mi_cmdline;␊
165 if(end != NULL)␊
166 {␊
167 for(; *end != '\0'; ++end)␊
168 ;␊
169 ++end;␊
170 if( (void*)end > hi_addr)␊
171 hi_addr = end;␊
172 }␊
173 }␊
174 // Make sure the module information isn't in high memory␊
175 if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_MODS)␊
176 {␊
177 struct multiboot_module *modules = (void*)mi_orig->mi_mods_addr;␊
178 int i;␊
179 for(i=0; i < mi_orig->mi_mods_count; ++i)␊
180 {␊
181 // make sure the multiboot_module struct itself won't get clobbered␊
182 void *modinfo_end = modules+i+1;␊
183 if(modinfo_end > hi_addr)␊
184 hi_addr = modinfo_end;␊
185 // make sure the module itself won't get clobbered␊
186 modinfo_end = (void*)modules[i].mm_mod_end;␊
187 if(modinfo_end > hi_addr)␊
188 hi_addr = modinfo_end;␊
189 // make sure the module string doesn't get clobbered␊
190 char *end = modules[i].mm_string;␊
191 for(; *end != '\0'; ++end)␊
192 ;␊
193 ++end;␊
194 modinfo_end = end;␊
195 if(modinfo_end > hi_addr)␊
196 hi_addr = modinfo_end;␊
197 }␊
198 }␊
199 // TODO: Copy syms (never needed), mmap, drives, config table, loader name, apm table, VBE info␊
200␊
201 // Round up to page size␊
202 hi_addr = (void*)(((uint32_t)hi_addr + 0xfff) & ~(uint32_t)0xfff);␊
203 return hi_addr;␊
204}␊
205␊
206/*!␊
207 Like malloc but with a preceding input/output parameter which points to the next available␊
208 location for data. The original value of *hi_addr is returned and *hi_addr is incremented␊
209 by size bytes.␊
210 */␊
211void * _hi_malloc(void **hi_addr, size_t size)␊
212{␊
213 void *ret = *hi_addr;␊
214 *hi_addr += size;␊
215 return ret;␊
216}␊
217␊
218/*!␊
219 Like strdup but with a preceding input/output parameter. The original value of *hi_addr is␊
220 returned and *hi_addr is incremented by the number of bytes necessary to complete the string␊
221 copy including its NUL terminator.␊
222 */␊
223char * _hi_strdup(void **hi_addr, char *src)␊
224{␊
225 char *dstStart;␊
226 char *dst = dstStart = *hi_addr;␊
227 for(; *src != '\0'; ++src, ++dst, ++(*hi_addr))␊
228 *dst = *src;␊
229 *dst = '\0';␊
230 ++(*hi_addr);␊
231 return dstStart;␊
232}␊
233␊
234// Convenience macros␊
235#define hi_malloc(size) _hi_malloc(&hi_addr, (size))␊
236#define hi_strdup(src) _hi_strdup(&hi_addr, (src))␊
237␊
238/*!␊
239 Copies the Multiboot info and any associated data (e.g. various strings and any multiboot modules)␊
240 up to very high RAM (above 128 MB) to ensure it doesn't get clobbered by the booter.␊
241 */␊
242struct multiboot_info * copyMultibootInfo(int multiboot_magic, struct multiboot_info *mi_orig)␊
243{␊
244 void *hi_addr = determine_safe_hi_addr(multiboot_magic, mi_orig);␊
245 if(hi_addr == NULL)␊
246 return NULL;␊
247␊
248 struct multiboot_info *mi_copy = hi_malloc(sizeof(*mi_copy));␊
249 memcpy(mi_copy, mi_orig, sizeof(*mi_copy));␊
250 ␊
251 // Copy the command line␊
252 if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊
253 {␊
254 mi_copy->mi_cmdline = hi_strdup(mi_orig->mi_cmdline);␊
255 }␊
256 // Copy the loader name␊
257 if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_LOADER_NAME)␊
258 {␊
259 mi_copy->mi_loader_name = hi_strdup(mi_orig->mi_loader_name);␊
260 }␊
261 // Copy the module info␊
262 if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_MODS)␊
263 {␊
264 struct multiboot_module *dst_modules = hi_malloc(sizeof(*dst_modules)*mi_orig->mi_mods_count);␊
265 struct multiboot_module *src_modules = (void*)mi_orig->mi_mods_addr;␊
266 mi_copy->mi_mods_addr = (uint32_t)dst_modules;␊
267␊
268 // Copy all of the module info plus the actual module into high memory␊
269 int i;␊
270 for(i=0; i < mi_orig->mi_mods_count; ++i)␊
271 {␊
272 // Assume mod_end is 1 past the actual end (i.e. it is start + size, not really end (i.e. start + size - 1))␊
273 // This is what GRUB and mboot.c32 do although the spec is unclear on this.␊
274 uint32_t mod_length = src_modules[i].mm_mod_end - src_modules[i].mm_mod_start;␊
275␊
276 dst_modules[i].mm_mod_start = (uint32_t)hi_malloc(mod_length);␊
277 dst_modules[i].mm_mod_end = (uint32_t)dst_modules[i].mm_mod_start + mod_length;␊
278 memcpy((char*)dst_modules[i].mm_mod_start, (char*)src_modules[i].mm_mod_start, mod_length);␊
279 ␊
280 dst_modules[i].mm_string = hi_strdup(src_modules[i].mm_string);␊
281 dst_modules[i].mm_reserved = src_modules[i].mm_reserved;␊
282 }␊
283 }␊
284 // Make sure that only stuff that didn't need to be copied or that we did deep copy is indicated in the copied struct.␊
285 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;␊
286␊
287 return mi_copy;␊
288}␊
289␊
290// When we enter, we're actually 1 MB high.␊
291// Fortunately, memcpy is position independent, and it's all we need␊
292uint32_t hi_multiboot(int multiboot_magic, struct multiboot_info *mi_orig)␊
293{␊
294 // Copy the multiboot info out of the way.␊
295 // We can't bitch about the magic yet because printf won't work␊
296 // because it contains an absolute location of putchar which␊
297 // contains absolute locations to other things which eventually␊
298 // makes a BIOS call from real mode which of course won't work␊
299 // because we're stuck in extended memory at this point.␊
300 struct multiboot_info *mi_p = copyMultibootInfo(multiboot_magic, mi_orig);␊
301␊
302 // Get us in to low memory so we can run everything␊
303␊
304 // We cannot possibly be more than 383.5k and copying extra won't really hurt anything␊
305 // We use the address of the assembly entrypoint to get our starting location.␊
306 memcpy(&boot2_sym, (char*)&boot2_sym + OFFSET_1MEG, 0x5fe00 /* 383.5k */);␊
307␊
308 // This is a little assembler routine that returns to us in the correct selector␊
309 // instead of the kernel selector we're running in now and at the correct␊
310 // instruction pointer ( current minus 1 MB ). It does not fix our return␊
311 // address nor does it fix the return address of our caller.␊
312 continue_at_low_address();␊
313␊
314 // Now fix our return address.␊
315 FIX_RETURN_ADDRESS_USING_FIRST_ARG(multiboot_magic);␊
316␊
317 // We can now do just about anything, including return to our caller correctly.␊
318 // However, our caller must fix his return address if he wishes to return to␊
319 // his caller and so on and so forth.␊
320␊
321 /* Zero the BSS and initialize malloc */␊
322 initialize_runtime();␊
323␊
324 gMI = mi_p;␊
325␊
326 /* Set up a temporary bootArgs so we can call console output routines␊
327 like printf that check the v_display. Note that we purposefully␊
328 do not initialize anything else at this early stage.␊
329␊
330 We are reasonably sure we're already in text mode if GRUB booted us.␊
331 This is the same assumption that initKernBootStruct makes.␊
332 We could check the multiboot info I guess, but why bother?␊
333 */␊
334 boot_args temporaryBootArgsData;␊
335 bzero(&temporaryBootArgsData, sizeof(boot_args));␊
336 bootArgs = &temporaryBootArgsData;␊
337 bootArgs->Video.v_display = VGA_TEXT_MODE;␊
338␊
339 // Install ramdisk and extra driver hooks␊
340 p_get_ramdisk_info = &multiboot_get_ramdisk_info;␊
341 p_ramdiskReadBytes = &multibootRamdiskReadBytes;␊
342 LoadExtraDrivers_p = &multiboot_LoadExtraDrivers;␊
343␊
344 // Since we call multiboot ourselves, its return address will be correct.␊
345 // That is unless it's inlined in which case it does not matter.␊
346 uint32_t bootdevice = multiboot(multiboot_magic, mi_p);␊
347 // We're about to exit and temporaryBootArgs will no longer be valid␊
348 bootArgs = NULL;␊
349 return bootdevice;␊
350}␊
351␊
352enum {␊
353 kReturnKey = 0x0d,␊
354 kEscapeKey = 0x1b,␊
355 kBackspaceKey = 0x08,␊
356 kASCIIKeyMask = 0x7f␊
357};␊
358␊
359// This is the meat of our implementation. It grabs the boot device from␊
360// the multiboot_info and returns it as is. If it fails it returns␊
361// BAD_BOOT_DEVICE. We can call an awful lot of libsa and libsaio but␊
362// we need to take care not to call anything that requires malloc because␊
363// it won't be initialized until boot() does it.␊
364static inline uint32_t multiboot(int multiboot_magic, struct multiboot_info *mi)␊
365{␊
366 if(multiboot_magic != MULTIBOOT_INFO_MAGIC)␊
367 {␊
368 printf("Wrong Multiboot magic\n");␊
369 sleep(2);␊
370 return BAD_BOOT_DEVICE;␊
371 }␊
372 printf("Multiboot info @0x%x\n", (uint32_t)mi);␊
373 if(mi->mi_flags & MULTIBOOT_INFO_HAS_LOADER_NAME)␊
374 printf("Loaded by %s\n", mi->mi_loader_name);␊
375␊
376 // Multiboot puts boot device in high byte␊
377 // Normal booter wants it in low byte␊
378 int bootdevice = mi->mi_boot_device_drive;␊
379␊
380 bool doSelectDevice = false;␊
381 if(mi->mi_flags & MULTIBOOT_INFO_HAS_BOOT_DEVICE)␊
382 {␊
383 printf("Boot device 0x%x\n", bootdevice);␊
384 }␊
385 else␊
386 {␊
387 printf("Multiboot info does not include chosen boot device\n");␊
388 doSelectDevice = true;␊
389 bootdevice = BAD_BOOT_DEVICE;␊
390 }␊
391 if(mi->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊
392 {␊
393 const char *val;␊
394 int size;␊
395 ␊
396 if(getValueForBootKey(mi->mi_cmdline, "biosdev", &val, &size))␊
397 {␊
398 char *endptr;␊
399 int intVal = strtol(val, &endptr, 16 /* always hex */);␊
400 if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊
401 {␊
402 printf("Boot device overridden to %02x with biosdev=%s\n", intVal, val);␊
403 bootdevice = intVal;␊
404 doSelectDevice = false;␊
405 }␊
406 else␊
407 doSelectDevice = true;␊
408 }␊
409␉␉␊
410 if(getValueForBootKey(mi->mi_cmdline, "timeout", &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("Timeout overridden to %d with timeout=%s\n", intVal, val);␊
417 multiboot_timeout = intVal;␊
418 multiboot_timeout_set = 1;␊
419 }␊
420 }␉␉␊
421␉␉␊
422 if(getValueForBootKey(mi->mi_cmdline, "partno", &val, &size))␊
423 {␊
424 char *endptr;␊
425 int intVal = strtol(val, &endptr, 0);␊
426 if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊
427 {␊
428 printf("Default partition overridden to %d with timeout=%s\n", intVal, val);␊
429 multiboot_partition = intVal;␊
430 multiboot_partition_set = 1;␊
431 }␊
432 }␉␉␉␉␊
433 }␊
434 if(doSelectDevice)␊
435 {␊
436 bootdevice = selectAlternateBootDevice(bootdevice);␊
437 }␊
438 if(bootdevice == BAD_BOOT_DEVICE)␊
439 sleep(2); // pause for a second before halting␊
440 return bootdevice;␊
441}␊
442␊
443///////////////////////////////////////////////////////////////////////////␊
444// Ramdisk and extra drivers code␊
445␊
446int multibootRamdiskReadBytes( int biosdev, unsigned int blkno,␊
447 unsigned int byteoff,␊
448 unsigned int byteCount, void * buffer )␊
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␊
458 void *p_initrd = (void*)module->mm_mod_start;␊
459 bcopy(p_initrd + blkno*512 + byteoff, buffer, byteCount);␊
460 return 0;␊
461}␊
462␊
463int multiboot_get_ramdisk_info(int biosdev, struct driveInfo *dip)␊
464{␊
465 int module_count = gMI->mi_mods_count;␊
466 struct multiboot_module *modules = (void*)gMI->mi_mods_addr;␊
467 if(biosdev < 0x100)␊
468 return -1;␊
469 if(biosdev >= (0x100 + module_count))␊
470 return -1;␊
471 struct multiboot_module *module = modules + (biosdev - 0x100);␊
472 dip->biosdev = biosdev;␊
473 dip->uses_ebios = true;␉// XXX aserebln uses_ebios isn't a boolean at all␊
474 dip->di.params.phys_sectors = (module->mm_mod_end - module->mm_mod_start + 511) / 512;␊
475 dip->valid = true;␊
476 return 0;␊
477}␊
478␊
479static long multiboot_LoadExtraDrivers(FileLoadDrivers_t FileLoadDrivers_p)␊
480{␊
481 char extensionsSpec[1024];␊
482 int ramdiskUnit;␊
483 for(ramdiskUnit = 0; ramdiskUnit < gMI->mi_mods_count; ++ramdiskUnit)␊
484 {␊
485 int partCount; // unused␊
486 BVRef ramdiskChain = diskScanBootVolumes(0x100 + ramdiskUnit, &partCount);␊
487 if(ramdiskChain == NULL)␊
488 {␊
489 verbose("Ramdisk contains no partitions\n");␊
490 continue;␊
491 }␊
492 for(; ramdiskChain != NULL; ramdiskChain = ramdiskChain->next)␊
493 {␊
494 sprintf(extensionsSpec, "rd(%d,%d)/Extra/", ramdiskUnit, ramdiskChain->part_no);␊
495 struct dirstuff *extradir = opendir(extensionsSpec);␊
496 closedir(extradir);␊
497 if(extradir != NULL)␊
498 {␊
499 int ret = FileLoadDrivers_p(extensionsSpec, 0 /* this is a kext root dir, not a kext with plugins */);␊
500 if(ret != 0)␊
501 {␊
502 verbose("FileLoadDrivers failed on a ramdisk\n");␊
503 return ret;␊
504 }␊
505 }␊
506 }␊
507 }␊
508 return 0;␊
509}␊
510#endif

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