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();␊ |
45 | extern unsigned char chainbootdev;␊ |
46 | extern unsigned char chainbootflag;␊ |
47 | ␊ |
48 | void chainLoad();␊ |
49 | void waitThenReload();␊ |
50 | ␊ |
51 | // Starts off in the multiboot context 1 MB high but eventually gets into low memory␊ |
52 | // and winds up with a bootdevice in eax which is all that boot() wants␊ |
53 | // This lets the stack pointer remain very high.␊ |
54 | // If we were to call boot directly from multiboot then the whole multiboot_info␊ |
55 | // would be on the stack which would possibly be using way too much stack.␊ |
56 | void multiboot_to_boot(int multiboot_magic, struct multiboot_info *mi_orig)␊ |
57 | {␊ |
58 | uint32_t bootdevice = hi_multiboot(multiboot_magic, mi_orig);␊ |
59 | if(bootdevice != BAD_BOOT_DEVICE)␊ |
60 | {␊ |
61 | // boot only returns to do a chain load.␊ |
62 | for(;;)␊ |
63 | { // NOTE: boot only uses the last byte (the drive number)␊ |
64 | common_boot(bootdevice);␊ |
65 | if(chainbootflag)␊ |
66 | chainLoad();␊ |
67 | else␊ |
68 | waitThenReload();␊ |
69 | }␊ |
70 | }␊ |
71 | // Avoid returning to high-memory address which isn't valid in the segment␊ |
72 | // we are now in.␊ |
73 | // Calling sleep() ensures the user ought to be able to use Ctrl+Alt+Del␊ |
74 | // because the BIOS will have interrupts on.␊ |
75 | for(;;)␊ |
76 | sleep(10);␊ |
77 | // NOTE: *IF* we needed to return we'd have to fix up our return address to␊ |
78 | // be in low memory using the same trick as below.␊ |
79 | // However, there doesn't seem to be any point in returning to assembly␊ |
80 | // particularly when the remaining code merely halts the processor.␊ |
81 | }␊ |
82 | ␊ |
83 | void chainLoad()␊ |
84 | {␊ |
85 | /* TODO: We ought to load the appropriate partition table, for example␊ |
86 | the MBR if booting a primary partition or the particular extended␊ |
87 | partition table if booting a logical drive. For example, the␊ |
88 | regular MS MBR booter will relocate itself (e.g. the MBR) from␊ |
89 | 0:7C00 to 0:0600 and will use SI as the offset when reading␊ |
90 | the partition data from itself. Thus when it jumps to the partition␊ |
91 | boot sector, SI will be 0x600 + 446 + i<<4 where i is the partition␊ |
92 | table index.␊ |
93 | ␊ |
94 | On the other hand, our code for the non-Multiboot case doesn't do␊ |
95 | this either, although GRUB does.␊ |
96 | */␊ |
97 | ␊ |
98 | const unsigned char *bootcode = (const unsigned char*)0x7c00;␊ |
99 | if(bootcode[0x1fe] == 0x55 && bootcode[0x1ff] == 0xaa)␊ |
100 | {␊ |
101 | printf("Calling chainbooter\n");␊ |
102 | jump_to_chainbooter();␊ |
103 | /* NORETURN */␊ |
104 | }␊ |
105 | else␊ |
106 | {␊ |
107 | printf("Bad chain boot sector magic: %02x%02x\n", bootcode[0x1fe], bootcode[0x1ff]);␊ |
108 | }␊ |
109 | }␊ |
110 | ␊ |
111 | void waitThenReload()␊ |
112 | {␊ |
113 | /* FIXME: Ctrl+Alt+Del does not work under Boot Camp */␊ |
114 | ␉uint8_t i = 5;␊ |
115 | printf("Darwin booter exited for some reason.\n");␊ |
116 | printf("Please reboot (Ctrl+Alt+Del) your machine.\n");␊ |
117 | printf("Restarting Darwin booter in %d seconds...",i);␊ |
118 | sleep(1);␉␊ |
119 | ␉while (1 < i--) {␊ |
120 | ␉␉printf("%d...",i);␊ |
121 | ␉␉sleep(1);␊ |
122 | ␉}␊ |
123 | ␉printf("0\n");␊ |
124 | }␊ |
125 | ␊ |
126 | // Declare boot2_sym as an opaque struct so it can't be converted to a pointer␊ |
127 | // i.e. ensure the idiot programmer (me) makes sure to use address-of␊ |
128 | // Technically it's a function but it's real mode code and we sure don't␊ |
129 | // want to call it under any circumstances.␊ |
130 | extern struct {} boot2_sym asm("boot2");␊ |
131 | ␊ |
132 | // prototype multiboot and keep its implementation below hi_multiboot to␊ |
133 | // ensure that it doesn't get inlined by the compiler␊ |
134 | static inline uint32_t multiboot(int multiboot_magic, struct multiboot_info *mi);␊ |
135 | ␊ |
136 | ␊ |
137 | /*!␊ |
138 | Returns a pointer to the first safe address we can use for stowing the multiboot info.␊ |
139 | This might actually be a bit pedantic because mboot.c32 and GRUB both stow the multiboot␊ |
140 | info in low memory meaning that the >= 128 MB location we choose is plenty high enough.␊ |
141 | */␊ |
142 | void *determine_safe_hi_addr(int multiboot_magic, struct multiboot_info *mi_orig)␊ |
143 | {␊ |
144 | // hi_addr must be at least up in 128MB+ space so it doesn't get clobbered␊ |
145 | void *hi_addr = (void*)PREBOOT_DATA;␊ |
146 | ␊ |
147 | // Fail if the magic isn't correct. We'll complain later.␊ |
148 | if(multiboot_magic != MULTIBOOT_INFO_MAGIC)␊ |
149 | return NULL;␊ |
150 | // Make sure the command-line isn't in high memory.␊ |
151 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊ |
152 | {␊ |
153 | char *end = mi_orig->mi_cmdline;␊ |
154 | if(end != NULL)␊ |
155 | {␊ |
156 | for(; *end != '\0'; ++end)␊ |
157 | ;␊ |
158 | ++end;␊ |
159 | if( (void*)end > hi_addr)␊ |
160 | hi_addr = end;␊ |
161 | }␊ |
162 | }␊ |
163 | // Make sure the module information isn't in high memory␊ |
164 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_MODS)␊ |
165 | {␊ |
166 | struct multiboot_module *modules = (void*)mi_orig->mi_mods_addr;␊ |
167 | uint32_t i;␊ |
168 | for(i=0; i < mi_orig->mi_mods_count; ++i)␊ |
169 | {␊ |
170 | // make sure the multiboot_module struct itself won't get clobbered␊ |
171 | void *modinfo_end = modules+i+1;␊ |
172 | if(modinfo_end > hi_addr)␊ |
173 | hi_addr = modinfo_end;␊ |
174 | // make sure the module itself won't get clobbered␊ |
175 | modinfo_end = (void*)modules[i].mm_mod_end;␊ |
176 | if(modinfo_end > hi_addr)␊ |
177 | hi_addr = modinfo_end;␊ |
178 | // make sure the module string doesn't get clobbered␊ |
179 | char *end = modules[i].mm_string;␊ |
180 | for(; *end != '\0'; ++end)␊ |
181 | ;␊ |
182 | ++end;␊ |
183 | modinfo_end = end;␊ |
184 | if(modinfo_end > hi_addr)␊ |
185 | hi_addr = modinfo_end;␊ |
186 | }␊ |
187 | }␊ |
188 | // TODO: Copy syms (never needed), mmap, drives, config table, loader name, apm table, VBE info␊ |
189 | ␊ |
190 | // Round up to page size␊ |
191 | hi_addr = (void*)(((uint32_t)hi_addr + 0xfff) & ~(uint32_t)0xfff);␊ |
192 | return hi_addr;␊ |
193 | }␊ |
194 | ␊ |
195 | /*!␊ |
196 | Like malloc but with a preceding input/output parameter which points to the next available␊ |
197 | location for data. The original value of *hi_addr is returned and *hi_addr is incremented␊ |
198 | by size bytes.␊ |
199 | */␊ |
200 | void * _hi_malloc(void **hi_addr, size_t size)␊ |
201 | {␊ |
202 | void *ret = *hi_addr;␊ |
203 | *hi_addr += size;␊ |
204 | return ret;␊ |
205 | }␊ |
206 | ␊ |
207 | /*!␊ |
208 | Like strdup but with a preceding input/output parameter. The original value of *hi_addr is␊ |
209 | returned and *hi_addr is incremented by the number of bytes necessary to complete the string␊ |
210 | copy including its NUL terminator.␊ |
211 | */␊ |
212 | char * _hi_strdup(void **hi_addr, char *src)␊ |
213 | {␊ |
214 | char *dstStart;␊ |
215 | char *dst = dstStart = *hi_addr;␊ |
216 | for(; *src != '\0'; ++src, ++dst, ++(*hi_addr))␊ |
217 | *dst = *src;␊ |
218 | *dst = '\0';␊ |
219 | ++(*hi_addr);␊ |
220 | return dstStart;␊ |
221 | }␊ |
222 | ␊ |
223 | // Convenience macros␊ |
224 | #define hi_malloc(size) _hi_malloc(&hi_addr, (size))␊ |
225 | #define hi_strdup(src) _hi_strdup(&hi_addr, (src))␊ |
226 | ␊ |
227 | /*!␊ |
228 | Copies the Multiboot info and any associated data (e.g. various strings and any multiboot modules)␊ |
229 | up to very high RAM (above 128 MB) to ensure it doesn't get clobbered by the booter.␊ |
230 | */␊ |
231 | struct multiboot_info * copyMultibootInfo(int multiboot_magic, struct multiboot_info *mi_orig)␊ |
232 | {␊ |
233 | void *hi_addr = determine_safe_hi_addr(multiboot_magic, mi_orig);␊ |
234 | if(hi_addr == NULL)␊ |
235 | return NULL;␊ |
236 | ␊ |
237 | struct multiboot_info *mi_copy = hi_malloc(sizeof(struct multiboot_info));␊ |
238 | memcpy(mi_copy, mi_orig, sizeof(struct multiboot_info));␊ |
239 | ␊ |
240 | // Copy the command line␊ |
241 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊ |
242 | {␊ |
243 | mi_copy->mi_cmdline = hi_strdup(mi_orig->mi_cmdline);␊ |
244 | }␊ |
245 | // Copy the loader name␊ |
246 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_LOADER_NAME)␊ |
247 | {␊ |
248 | mi_copy->mi_loader_name = hi_strdup(mi_orig->mi_loader_name);␊ |
249 | }␊ |
250 | // Copy the module info␊ |
251 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_MODS)␊ |
252 | { ␊ |
253 | struct multiboot_module *dst_modules = hi_malloc(sizeof(struct multiboot_module) * mi_orig->mi_mods_count);␊ |
254 | ␊ |
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 | ␉␊ |
312 | /* Zero the BSS and initialize malloc */␊ |
313 | initialize_runtime();␊ |
314 | ␊ |
315 | gMI = mi_p;␊ |
316 | ␊ |
317 | /* Set up a temporary bootArgs so we can call console output routines␊ |
318 | like printf that check the v_display. Note that we purposefully␊ |
319 | do not initialize anything else at this early stage.␊ |
320 | ␊ |
321 | We are reasonably sure we're already in text mode if GRUB booted us.␊ |
322 | This is the same assumption that initKernBootStruct makes.␊ |
323 | We could check the multiboot info I guess, but why bother?␊ |
324 | */␊ |
325 | boot_args temporaryBootArgsData;␊ |
326 | bzero(&temporaryBootArgsData, sizeof(boot_args));␊ |
327 | bootArgs = &temporaryBootArgsData;␊ |
328 | bootArgs->Video.v_display = VGA_TEXT_MODE;␊ |
329 | ␊ |
330 | ␊ |
331 | // Since we call multiboot ourselves, its return address will be correct.␊ |
332 | // That is unless it's inlined in which case it does not matter.␊ |
333 | uint32_t bootdevice = multiboot(multiboot_magic, mi_p);␊ |
334 | // We're about to exit and temporaryBootArgs will no longer be valid␊ |
335 | bootArgs = NULL;␊ |
336 | return bootdevice;␊ |
337 | }␊ |
338 | ␊ |
339 | // This is the meat of our implementation. It grabs the boot device from␊ |
340 | // the multiboot_info and returns it as is. If it fails it returns␊ |
341 | // BAD_BOOT_DEVICE. We can call an awful lot of libsa and libsaio but␊ |
342 | // we need to take care not to call anything that requires malloc because␊ |
343 | // it won't be initialized until boot() does it.␊ |
344 | static inline uint32_t multiboot(int multiboot_magic, struct multiboot_info *mi)␊ |
345 | {␊ |
346 | if(multiboot_magic != MULTIBOOT_INFO_MAGIC)␊ |
347 | {␊ |
348 | printf("Wrong Multiboot magic\n");␊ |
349 | sleep(2);␊ |
350 | return BAD_BOOT_DEVICE;␊ |
351 | }␊ |
352 | printf("Multiboot info @0x%x\n", (uint32_t)mi);␊ |
353 | if(mi->mi_flags & MULTIBOOT_INFO_HAS_LOADER_NAME)␊ |
354 | printf("Loaded by %s\n", mi->mi_loader_name);␊ |
355 | ␊ |
356 | // Multiboot puts boot device in high byte␊ |
357 | // Normal booter wants it in low byte␊ |
358 | uint32_t bootdevice = mi->mi_boot_device_drive;␊ |
359 | ␊ |
360 | //bool doSelectDevice = false;␊ |
361 | if(mi->mi_flags & MULTIBOOT_INFO_HAS_BOOT_DEVICE)␊ |
362 | {␊ |
363 | printf("Boot device 0x%x\n", bootdevice);␊ |
364 | }␊ |
365 | else␊ |
366 | {␊ |
367 | printf("Multiboot info does not include chosen boot device\n");␊ |
368 | //doSelectDevice = true;␊ |
369 | bootdevice = BAD_BOOT_DEVICE;␊ |
370 | }␊ |
371 | if(mi->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊ |
372 | {␊ |
373 | const char *val;␊ |
374 | int size;␊ |
375 | ␊ |
376 | if(getValueForBootKey(mi->mi_cmdline, "biosdev", &val, &size))␊ |
377 | {␊ |
378 | char *endptr;␊ |
379 | int intVal = strtol(val, &endptr, 16 /* always hex */);␊ |
380 | if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊ |
381 | {␊ |
382 | printf("Boot device overridden to %02x with biosdev=%s\n", intVal, val);␊ |
383 | bootdevice = intVal;␊ |
384 | //doSelectDevice = false;␊ |
385 | }␊ |
386 | //else␊ |
387 | // doSelectDevice = true;␊ |
388 | }␊ |
389 | #if UNUSED␉␉␊ |
390 | if(getValueForBootKey(mi->mi_cmdline, "timeout", &val, &size))␊ |
391 | {␊ |
392 | char *endptr;␊ |
393 | int intVal = strtol(val, &endptr, 0);␊ |
394 | if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊ |
395 | {␊ |
396 | printf("Timeout overridden to %d with timeout=%s\n", intVal, val);␊ |
397 | multiboot_timeout = intVal;␊ |
398 | multiboot_timeout_set = 1;␊ |
399 | }␊ |
400 | }␉␉␊ |
401 | ␉␉␊ |
402 | if(getValueForBootKey(mi->mi_cmdline, "partno", &val, &size))␊ |
403 | {␊ |
404 | char *endptr;␊ |
405 | int intVal = strtol(val, &endptr, 0);␊ |
406 | if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊ |
407 | {␊ |
408 | printf("Default partition overridden to %d with timeout=%s\n", intVal, val);␊ |
409 | multiboot_partition = intVal;␊ |
410 | multiboot_partition_set = 1;␊ |
411 | }␊ |
412 | }␊ |
413 | #endif␊ |
414 | }␊ |
415 | if(bootdevice == BAD_BOOT_DEVICE)␊ |
416 | sleep(2); // pause for a second before halting␊ |
417 | return bootdevice;␊ |
418 | }␊ |
419 | |