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␊ |
16 | int multiboot_timeout=0;␊ |
17 | int multiboot_timeout_set=0;␊ |
18 | int multiboot_partition=0;␊ |
19 | int multiboot_partition_set=0;␊ |
20 | #endif␊ |
21 | // Global multiboot info, if using multiboot.␊ |
22 | ␊ |
23 | extern 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.␊ |
30 | uint32_t hi_multiboot(int multiboot_magic, struct multiboot_info *mi_orig);␊ |
31 | // prototype dochainload for the same reason.␊ |
32 | void 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 | ␊ |
44 | extern void jump_to_chainbooter(void);␊ |
45 | extern unsigned char chainbootdev;␊ |
46 | extern unsigned char chainbootflag;␊ |
47 | ␊ |
48 | void chainLoad(void);␊ |
49 | void waitThenReload(void);␊ |
50 | void multiboot_to_boot(int multiboot_magic, struct multiboot_info *mi_orig);␊ |
51 | void *determine_safe_hi_addr(int multiboot_magic, struct multiboot_info *mi_orig);␊ |
52 | void * _hi_malloc(void **hi_addr, size_t size);␊ |
53 | char * _hi_strdup(void **hi_addr, char *src);␊ |
54 | struct multiboot_info * copyMultibootInfo(int multiboot_magic, struct multiboot_info *mi_orig);␊ |
55 | static 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.␊ |
62 | void 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 | ␊ |
89 | void 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 | ␊ |
117 | void 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.␊ |
136 | extern 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␊ |
140 | static 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 | */␊ |
148 | void *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 | */␊ |
206 | void * _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 | */␊ |
218 | char * _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 | */␊ |
237 | struct 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 | ␉if (!mi_copy) {␊ |
245 | ␉␉iloop();␊ |
246 | ␉}␊ |
247 | memcpy(mi_copy, mi_orig, sizeof(struct multiboot_info));␊ |
248 | ␊ |
249 | // Copy the command line␊ |
250 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊ |
251 | {␊ |
252 | mi_copy->mi_cmdline = hi_strdup(mi_orig->mi_cmdline);␊ |
253 | }␊ |
254 | // Copy the loader name␊ |
255 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_LOADER_NAME)␊ |
256 | {␊ |
257 | mi_copy->mi_loader_name = hi_strdup(mi_orig->mi_loader_name);␊ |
258 | }␊ |
259 | // Copy the module info␊ |
260 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_MODS)␊ |
261 | { ␊ |
262 | struct multiboot_module *dst_modules = hi_malloc(sizeof(struct multiboot_module) * mi_orig->mi_mods_count);␊ |
263 | ␉␉if (!dst_modules) {␊ |
264 | ␉␉␉iloop();␊ |
265 | ␉␉}␊ |
266 | struct multiboot_module *src_modules = (void*)mi_orig->mi_mods_addr;␊ |
267 | mi_copy->mi_mods_addr = (uint32_t)dst_modules;␊ |
268 | ␉␉␊ |
269 | // Copy all of the module info plus the actual module into high memory␊ |
270 | uint32_t i;␊ |
271 | for(i=0; i < mi_orig->mi_mods_count; ++i)␊ |
272 | {␊ |
273 | // Assume mod_end is 1 past the actual end (i.e. it is start + size, not really end (i.e. start + size - 1))␊ |
274 | // This is what GRUB and mboot.c32 do although the spec is unclear on this.␊ |
275 | uint32_t mod_length = src_modules[i].mm_mod_end - src_modules[i].mm_mod_start;␊ |
276 | ␉␉␉␊ |
277 | dst_modules[i].mm_mod_start = (uint32_t)hi_malloc(mod_length);␊ |
278 | ␉␉␉if (!dst_modules[i].mm_mod_start) {␊ |
279 | ␉␉␉␉iloop();␊ |
280 | ␉␉␉}␊ |
281 | dst_modules[i].mm_mod_end = (uint32_t)dst_modules[i].mm_mod_start + mod_length;␊ |
282 | memcpy((char*)dst_modules[i].mm_mod_start, (char*)src_modules[i].mm_mod_start, mod_length);␊ |
283 | ␊ |
284 | dst_modules[i].mm_string = hi_strdup(src_modules[i].mm_string);␊ |
285 | dst_modules[i].mm_reserved = src_modules[i].mm_reserved;␊ |
286 | }␊ |
287 | }␊ |
288 | // Make sure that only stuff that didn't need to be copied or that we did deep copy is indicated in the copied struct.␊ |
289 | 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;␊ |
290 | ␉␊ |
291 | return mi_copy;␊ |
292 | }␊ |
293 | ␊ |
294 | ␊ |
295 | // When we enter, we're actually 1 MB high.␊ |
296 | // Fortunately, memcpy is position independent, and it's all we need␊ |
297 | uint32_t hi_multiboot(int multiboot_magic, struct multiboot_info *mi_orig)␊ |
298 | {␊ |
299 | // Copy the multiboot info out of the way.␊ |
300 | // We can't bitch about the magic yet because printf won't work␊ |
301 | // because it contains an absolute location of putchar which␊ |
302 | // contains absolute locations to other things which eventually␊ |
303 | // makes a BIOS call from real mode which of course won't work␊ |
304 | // because we're stuck in extended memory at this point.␊ |
305 | struct multiboot_info *mi_p = copyMultibootInfo(multiboot_magic, mi_orig);␉␊ |
306 | ␉␊ |
307 | ␉if (mi_p == NULL) ␊ |
308 | return BAD_BOOT_DEVICE;␊ |
309 | #if 0␉␊ |
310 | /*␊ |
311 | * cparm: I'm not an asm guru but i don't see what's the use of this part of code, moreover some ␊ |
312 | * compilers seems to don't like this at all and crash during compilation, if it's really ␊ |
313 | * necesary maybe we should consider to do it in some other way␊ |
314 | */␊ |
315 | ␊ |
316 | // Get us in to low memory so we can run everything␊ |
317 | ␊ |
318 | // We cannot possibly be more than 383.5k and copying extra won't really hurt anything␊ |
319 | // We use the address of the assembly entrypoint to get our starting location.␊ |
320 | memcpy(&boot2_sym, (char*)&boot2_sym + OFFSET_1MEG, 0x5fe00 /* 383.5k */);␉␊ |
321 | #endif␊ |
322 | ␉␊ |
323 | // This is a little assembler routine that returns to us in the correct selector␊ |
324 | // instead of the kernel selector we're running in now and at the correct␊ |
325 | // instruction pointer ( current minus 1 MB ). It does not fix our return␊ |
326 | // address nor does it fix the return address of our caller.␊ |
327 | continue_at_low_address();␊ |
328 | ␉␊ |
329 | ␉// Now fix our return address.␉␊ |
330 | FIX_RETURN_ADDRESS_USING_FIRST_ARG(multiboot_magic);␊ |
331 | ␉␊ |
332 | // We can now do just about anything, including return to our caller correctly.␊ |
333 | // However, our caller must fix his return address if he wishes to return to␊ |
334 | // his caller and so on and so forth.␊ |
335 | ␉␊ |
336 | ␉␊ |
337 | ␉␊ |
338 | /* Zero the BSS and initialize malloc */␊ |
339 | initialize_runtime();␊ |
340 | ␉␊ |
341 | //gMI = mi_p;␊ |
342 | ␉␊ |
343 | /* Set up a temporary bootArgs so we can call console output routines␊ |
344 | ␉ like printf that check the v_display. Note that we purposefully␊ |
345 | ␉ do not initialize anything else at this early stage.␊ |
346 | ␉ ␊ |
347 | ␉ We are reasonably sure we're already in text mode if GRUB booted us.␊ |
348 | ␉ This is the same assumption that initKernBootStruct makes.␊ |
349 | ␉ We could check the multiboot info I guess, but why bother?␊ |
350 | */␊ |
351 | boot_args temporaryBootArgsData;␊ |
352 | bzero(&temporaryBootArgsData, sizeof(boot_args));␊ |
353 | bootArgs = &temporaryBootArgsData;␊ |
354 | bootArgs->Video.v_display = VGA_TEXT_MODE;␊ |
355 | ␉␊ |
356 | // Since we call multiboot ourselves, its return address will be correct.␊ |
357 | // That is unless it's inlined in which case it does not matter.␊ |
358 | uint32_t bootdevice = multiboot(multiboot_magic, mi_p);␊ |
359 | // We're about to exit and temporaryBootArgs will no longer be valid␊ |
360 | bootArgs = NULL;␊ |
361 | ␊ |
362 | return bootdevice;␊ |
363 | }␊ |
364 | ␊ |
365 | // This is the meat of our implementation. It grabs the boot device from␊ |
366 | // the multiboot_info and returns it as is. If it fails it returns␊ |
367 | // BAD_BOOT_DEVICE. We can call an awful lot of libsa and libsaio but␊ |
368 | // we need to take care not to call anything that requires malloc because␊ |
369 | // it won't be initialized until boot() does it.␊ |
370 | static inline uint32_t multiboot(int multiboot_magic, struct multiboot_info *mi)␊ |
371 | {␊ |
372 | if(multiboot_magic != MULTIBOOT_INFO_MAGIC)␊ |
373 | {␊ |
374 | printf("Wrong Multiboot magic\n");␊ |
375 | sleep(2);␊ |
376 | return BAD_BOOT_DEVICE;␊ |
377 | }␊ |
378 | printf("Multiboot info @0x%x\n", (uint32_t)mi);␊ |
379 | if(mi->mi_flags & MULTIBOOT_INFO_HAS_LOADER_NAME)␊ |
380 | printf("Loaded by %s\n", mi->mi_loader_name);␊ |
381 | ␉␊ |
382 | // Multiboot puts boot device in high byte␊ |
383 | // Normal booter wants it in low byte␊ |
384 | uint32_t bootdevice = mi->mi_boot_device_drive;␊ |
385 | ␉␊ |
386 | //bool doSelectDevice = false;␊ |
387 | if(mi->mi_flags & MULTIBOOT_INFO_HAS_BOOT_DEVICE)␊ |
388 | {␊ |
389 | printf("Boot device 0x%x\n", bootdevice);␊ |
390 | }␊ |
391 | else␊ |
392 | {␊ |
393 | printf("Multiboot info does not include chosen boot device\n");␊ |
394 | //doSelectDevice = true;␊ |
395 | bootdevice = BAD_BOOT_DEVICE;␊ |
396 | }␊ |
397 | if(mi->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊ |
398 | {␊ |
399 | const char *val;␊ |
400 | int size;␊ |
401 | ␊ |
402 | if(getValueForBootKey(mi->mi_cmdline, "biosdev", &val, &size))␊ |
403 | {␊ |
404 | char *endptr;␊ |
405 | int intVal = strtol(val, &endptr, 16 /* always hex */);␊ |
406 | if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊ |
407 | {␊ |
408 | printf("Boot device overridden to %02x with biosdev=%s\n", intVal, val);␊ |
409 | bootdevice = intVal;␊ |
410 | //doSelectDevice = false;␊ |
411 | }␊ |
412 | //else␊ |
413 | // doSelectDevice = true;␊ |
414 | }␊ |
415 | #if UNUSED␉␉␊ |
416 | if(getValueForBootKey(mi->mi_cmdline, "timeout", &val, &size))␊ |
417 | {␊ |
418 | char *endptr;␊ |
419 | int intVal = strtol(val, &endptr, 0);␊ |
420 | if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊ |
421 | {␊ |
422 | printf("Timeout overridden to %d with timeout=%s\n", intVal, val);␊ |
423 | multiboot_timeout = intVal;␊ |
424 | multiboot_timeout_set = 1;␊ |
425 | }␊ |
426 | }␉␉␊ |
427 | ␉␉␊ |
428 | if(getValueForBootKey(mi->mi_cmdline, "partno", &val, &size))␊ |
429 | {␊ |
430 | char *endptr;␊ |
431 | int intVal = strtol(val, &endptr, 0);␊ |
432 | if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊ |
433 | {␊ |
434 | printf("Default partition overridden to %d with timeout=%s\n", intVal, val);␊ |
435 | multiboot_partition = intVal;␊ |
436 | multiboot_partition_set = 1;␊ |
437 | }␊ |
438 | }␊ |
439 | #endif␊ |
440 | }␊ |
441 | if(bootdevice == BAD_BOOT_DEVICE)␊ |
442 | sleep(2); // pause for a second before halting␊ |
443 | return bootdevice;␊ |
444 | }␊ |
445 | |