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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#include "mboot.h"␊
9␊
10#define OFFSET_1MEG 0x100000␊
11#define BAD_BOOT_DEVICE 0xffffffff␊
12␊
13//struct multiboot_info *gMI;␊
14␊
15#if UNUSED␊
16int multiboot_timeout=0;␊
17int multiboot_timeout_set=0;␊
18int multiboot_partition=0;␊
19int multiboot_partition_set=0;␊
20#endif␊
21// Global multiboot info, if using multiboot.␊
22␊
23extern void continue_at_low_address(void);␊
24␊
25// prototype hi_multiboot and keep its implementation below multiboot_to_boot␊
26// to ensure that it doesn't get inlined by the compiler␊
27// We don't want it inlined because we specifically want the stack frame␊
28// pointer to be as high as possible and the hi_multiboot function␊
29// copies multiboot_info onto its stack.␊
30uint32_t hi_multiboot(int multiboot_magic, struct multiboot_info *mi_orig);␊
31// prototype dochainload for the same reason.␊
32void dochainload();␊
33␊
34␊
35// This assumes that the address of the first argument to the function will␊
36// be exactly 4 bytes above the address of the return address.␊
37// It is intended to be used as an lvalue with a statement like this -= OFFSET_1MEG;␊
38#define RETURN_ADDRESS_USING_FIRST_ARG(arg) \␊
39 (*(uint32_t*)((char*)&(arg) - 4))␊
40␊
41#define FIX_RETURN_ADDRESS_USING_FIRST_ARG(arg) \␊
42 RETURN_ADDRESS_USING_FIRST_ARG(arg) -= OFFSET_1MEG␊
43␊
44extern void jump_to_chainbooter(void);␊
45extern unsigned char chainbootdev;␊
46extern unsigned char chainbootflag;␊
47␊
48void chainLoad(void);␊
49void waitThenReload(void);␊
50void multiboot_to_boot(int multiboot_magic, struct multiboot_info *mi_orig);␊
51void *determine_safe_hi_addr(int multiboot_magic, struct multiboot_info *mi_orig);␊
52void * _hi_malloc(void **hi_addr, size_t size);␊
53char * _hi_strdup(void **hi_addr, char *src);␊
54struct multiboot_info * copyMultibootInfo(int multiboot_magic, struct multiboot_info *mi_orig);␊
55static inline uint32_t multiboot(int multiboot_magic, struct multiboot_info *mi);␊
56␊
57// Starts off in the multiboot context 1 MB high but eventually gets into low memory␊
58// and winds up with a bootdevice in eax which is all that boot() wants␊
59// This lets the stack pointer remain very high.␊
60// If we were to call boot directly from multiboot then the whole multiboot_info␊
61// would be on the stack which would possibly be using way too much stack.␊
62void multiboot_to_boot(int multiboot_magic, struct multiboot_info *mi_orig)␊
63{␊
64 uint32_t bootdevice = hi_multiboot(multiboot_magic, mi_orig);␊
65 if(bootdevice != BAD_BOOT_DEVICE)␊
66 {␊
67 // boot only returns to do a chain load.␊
68 for(;;)␊
69 { // NOTE: boot only uses the last byte (the drive number)␊
70 common_boot(bootdevice);␊
71 if(chainbootflag)␊
72 chainLoad();␊
73 else␊
74 waitThenReload();␊
75 }␊
76 }␊
77 // Avoid returning to high-memory address which isn't valid in the segment␊
78 // we are now in.␊
79 // Calling sleep() ensures the user ought to be able to use Ctrl+Alt+Del␊
80 // because the BIOS will have interrupts on.␊
81 for(;;)␊
82 sleep(10);␊
83 // NOTE: *IF* we needed to return we'd have to fix up our return address to␊
84 // be in low memory using the same trick as below.␊
85 // However, there doesn't seem to be any point in returning to assembly␊
86 // particularly when the remaining code merely halts the processor.␊
87}␊
88␊
89void chainLoad(void)␊
90{␊
91 /* TODO: We ought to load the appropriate partition table, for example␊
92 the MBR if booting a primary partition or the particular extended␊
93 partition table if booting a logical drive. For example, the␊
94 regular MS MBR booter will relocate itself (e.g. the MBR) from␊
95 0:7C00 to 0:0600 and will use SI as the offset when reading␊
96 the partition data from itself. Thus when it jumps to the partition␊
97 boot sector, SI will be 0x600 + 446 + i<<4 where i is the partition␊
98 table index.␊
99 ␊
100 On the other hand, our code for the non-Multiboot case doesn't do␊
101 this either, although GRUB does.␊
102 */␊
103␊
104 const unsigned char *bootcode = (const unsigned char*)0x7c00;␊
105 if(bootcode[0x1fe] == 0x55 && bootcode[0x1ff] == 0xaa)␊
106 {␊
107 printf("Calling chainbooter\n");␊
108 jump_to_chainbooter();␊
109 /* NORETURN */␊
110 }␊
111 else␊
112 {␊
113 printf("Bad chain boot sector magic: %02x%02x\n", bootcode[0x1fe], bootcode[0x1ff]);␊
114 }␊
115}␊
116␊
117void waitThenReload(void)␊
118{␊
119 /* FIXME: Ctrl+Alt+Del does not work under Boot Camp */␊
120␉uint8_t i = 5;␊
121 printf("Darwin booter exited for some reason.\n");␊
122 printf("Please reboot (Ctrl+Alt+Del) your machine.\n");␊
123 printf("Restarting Darwin booter in %d seconds...",i);␊
124 sleep(1);␉␊
125␉while (1 < i--) {␊
126␉␉printf("%d...",i);␊
127␉␉sleep(1);␊
128␉}␊
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 uint32_t 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(struct multiboot_info));␊
244 memcpy(mi_copy, mi_orig, sizeof(struct multiboot_info));␊
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(struct multiboot_module) * mi_orig->mi_mods_count);␊
260␊
261 struct multiboot_module *src_modules = (void*)mi_orig->mi_mods_addr;␊
262 mi_copy->mi_mods_addr = (uint32_t)dst_modules;␊
263␊
264 // Copy all of the module info plus the actual module into high memory␊
265 uint32_t i;␊
266 for(i=0; i < mi_orig->mi_mods_count; ++i)␊
267 {␊
268 // Assume mod_end is 1 past the actual end (i.e. it is start + size, not really end (i.e. start + size - 1))␊
269 // This is what GRUB and mboot.c32 do although the spec is unclear on this.␊
270 uint32_t mod_length = src_modules[i].mm_mod_end - src_modules[i].mm_mod_start;␊
271␊
272 dst_modules[i].mm_mod_start = (uint32_t)hi_malloc(mod_length);␊
273 dst_modules[i].mm_mod_end = (uint32_t)dst_modules[i].mm_mod_start + mod_length;␊
274 memcpy((char*)dst_modules[i].mm_mod_start, (char*)src_modules[i].mm_mod_start, mod_length);␊
275 ␊
276 dst_modules[i].mm_string = hi_strdup(src_modules[i].mm_string);␊
277 dst_modules[i].mm_reserved = src_modules[i].mm_reserved;␊
278 }␊
279 }␊
280 // Make sure that only stuff that didn't need to be copied or that we did deep copy is indicated in the copied struct.␊
281 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;␊
282␊
283 return mi_copy;␊
284}␊
285␊
286␊
287// When we enter, we're actually 1 MB high.␊
288// Fortunately, memcpy is position independent, and it's all we need␊
289uint32_t hi_multiboot(int multiboot_magic, struct multiboot_info *mi_orig)␊
290{␊
291 // Copy the multiboot info out of the way.␊
292 // We can't bitch about the magic yet because printf won't work␊
293 // because it contains an absolute location of putchar which␊
294 // contains absolute locations to other things which eventually␊
295 // makes a BIOS call from real mode which of course won't work␊
296 // because we're stuck in extended memory at this point.␊
297 struct multiboot_info *mi_p = copyMultibootInfo(multiboot_magic, mi_orig);␉␊
298␊
299␉if (mi_p == NULL) ␊
300 return BAD_BOOT_DEVICE;␊
301#if 0␉␊
302 /*␊
303 * cparm: I'm not an asm guru but i don't see what's the use of this part of code, moreover some ␊
304 * compilers seems to don't like this at all and crash during compilation, if it's really ␊
305 * necesary maybe we should consider to do it in some other way␊
306 */␊
307 ␊
308 // Get us in to low memory so we can run everything␊
309 ␊
310 // We cannot possibly be more than 383.5k and copying extra won't really hurt anything␊
311 // We use the address of the assembly entrypoint to get our starting location.␊
312 memcpy(&boot2_sym, (char*)&boot2_sym + OFFSET_1MEG, 0x5fe00 /* 383.5k */);␉␊
313#endif␊
314␉␊
315 // This is a little assembler routine that returns to us in the correct selector␊
316 // instead of the kernel selector we're running in now and at the correct␊
317 // instruction pointer ( current minus 1 MB ). It does not fix our return␊
318 // address nor does it fix the return address of our caller.␊
319 continue_at_low_address();␊
320␊
321␉// Now fix our return address.␉␊
322 FIX_RETURN_ADDRESS_USING_FIRST_ARG(multiboot_magic);␊
323␉␊
324 // We can now do just about anything, including return to our caller correctly.␊
325 // However, our caller must fix his return address if he wishes to return to␊
326 // his caller and so on and so forth.␊
327␊
328␊
329␉␊
330 /* Zero the BSS and initialize malloc */␊
331 initialize_runtime();␊
332␊
333 //gMI = mi_p;␊
334␊
335 /* Set up a temporary bootArgs so we can call console output routines␊
336 like printf that check the v_display. Note that we purposefully␊
337 do not initialize anything else at this early stage.␊
338␊
339 We are reasonably sure we're already in text mode if GRUB booted us.␊
340 This is the same assumption that initKernBootStruct makes.␊
341 We could check the multiboot info I guess, but why bother?␊
342 */␊
343 boot_args temporaryBootArgsData;␊
344 bzero(&temporaryBootArgsData, sizeof(boot_args));␊
345 bootArgs = &temporaryBootArgsData;␊
346 bootArgs->Video.v_display = VGA_TEXT_MODE;␊
347␊
348 // Since we call multiboot ourselves, its return address will be correct.␊
349 // That is unless it's inlined in which case it does not matter.␊
350 uint32_t bootdevice = multiboot(multiboot_magic, mi_p);␊
351 // We're about to exit and temporaryBootArgs will no longer be valid␊
352 bootArgs = NULL;␊
353 ␊
354 return bootdevice;␊
355}␊
356␊
357// This is the meat of our implementation. It grabs the boot device from␊
358// the multiboot_info and returns it as is. If it fails it returns␊
359// BAD_BOOT_DEVICE. We can call an awful lot of libsa and libsaio but␊
360// we need to take care not to call anything that requires malloc because␊
361// it won't be initialized until boot() does it.␊
362static inline uint32_t multiboot(int multiboot_magic, struct multiboot_info *mi)␊
363{␊
364 if(multiboot_magic != MULTIBOOT_INFO_MAGIC)␊
365 {␊
366 printf("Wrong Multiboot magic\n");␊
367 sleep(2);␊
368 return BAD_BOOT_DEVICE;␊
369 }␊
370 printf("Multiboot info @0x%x\n", (uint32_t)mi);␊
371 if(mi->mi_flags & MULTIBOOT_INFO_HAS_LOADER_NAME)␊
372 printf("Loaded by %s\n", mi->mi_loader_name);␊
373␊
374 // Multiboot puts boot device in high byte␊
375 // Normal booter wants it in low byte␊
376 uint32_t bootdevice = mi->mi_boot_device_drive;␊
377␊
378 //bool doSelectDevice = false;␊
379 if(mi->mi_flags & MULTIBOOT_INFO_HAS_BOOT_DEVICE)␊
380 {␊
381 printf("Boot device 0x%x\n", bootdevice);␊
382 }␊
383 else␊
384 {␊
385 printf("Multiboot info does not include chosen boot device\n");␊
386 //doSelectDevice = true;␊
387 bootdevice = BAD_BOOT_DEVICE;␊
388 }␊
389 if(mi->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊
390 {␊
391 const char *val;␊
392 int size;␊
393 ␊
394 if(getValueForBootKey(mi->mi_cmdline, "biosdev", &val, &size))␊
395 {␊
396 char *endptr;␊
397 int intVal = strtol(val, &endptr, 16 /* always hex */);␊
398 if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊
399 {␊
400 printf("Boot device overridden to %02x with biosdev=%s\n", intVal, val);␊
401 bootdevice = intVal;␊
402 //doSelectDevice = false;␊
403 }␊
404 //else␊
405 // doSelectDevice = true;␊
406 }␊
407#if UNUSED␉␉␊
408 if(getValueForBootKey(mi->mi_cmdline, "timeout", &val, &size))␊
409 {␊
410 char *endptr;␊
411 int intVal = strtol(val, &endptr, 0);␊
412 if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊
413 {␊
414 printf("Timeout overridden to %d with timeout=%s\n", intVal, val);␊
415 multiboot_timeout = intVal;␊
416 multiboot_timeout_set = 1;␊
417 }␊
418 }␉␉␊
419␉␉␊
420 if(getValueForBootKey(mi->mi_cmdline, "partno", &val, &size))␊
421 {␊
422 char *endptr;␊
423 int intVal = strtol(val, &endptr, 0);␊
424 if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊
425 {␊
426 printf("Default partition overridden to %d with timeout=%s\n", intVal, val);␊
427 multiboot_partition = intVal;␊
428 multiboot_partition_set = 1;␊
429 }␊
430 }␊
431#endif␊
432 }␊
433 if(bootdevice == BAD_BOOT_DEVICE)␊
434 sleep(2); // pause for a second before halting␊
435 return bootdevice;␊
436}␊
437

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Revision: 2006