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 | struct multiboot_info *gMI;␊ |
15 | ␊ |
16 | #if UNUSED␊ |
17 | int multiboot_timeout=0;␊ |
18 | int multiboot_timeout_set=0;␊ |
19 | int multiboot_partition=0;␊ |
20 | int multiboot_partition_set=0;␊ |
21 | #endif␊ |
22 | // Global multiboot info, if using multiboot.␊ |
23 | ␊ |
24 | extern void continue_at_low_address(void);␊ |
25 | ␊ |
26 | // prototype hi_multiboot and keep its implementation below multiboot_to_boot␊ |
27 | // to ensure that it doesn't get inlined by the compiler␊ |
28 | // We don't want it inlined because we specifically want the stack frame␊ |
29 | // pointer to be as high as possible and the hi_multiboot function␊ |
30 | // copies multiboot_info onto its stack.␊ |
31 | uint32_t hi_multiboot(int multiboot_magic, struct multiboot_info *mi_orig);␊ |
32 | // prototype dochainload for the same reason.␊ |
33 | void dochainload();␊ |
34 | ␊ |
35 | ␊ |
36 | // This assumes that the address of the first argument to the function will␊ |
37 | // be exactly 4 bytes above the address of the return address.␊ |
38 | // It is intended to be used as an lvalue with a statement like this -= OFFSET_1MEG;␊ |
39 | #define RETURN_ADDRESS_USING_FIRST_ARG(arg) \␊ |
40 | (*(uint32_t*)((char*)&(arg) - 4))␊ |
41 | ␊ |
42 | #define FIX_RETURN_ADDRESS_USING_FIRST_ARG(arg) \␊ |
43 | RETURN_ADDRESS_USING_FIRST_ARG(arg) -= OFFSET_1MEG␊ |
44 | ␊ |
45 | extern void jump_to_chainbooter();␊ |
46 | extern unsigned char chainbootdev;␊ |
47 | extern unsigned char chainbootflag;␊ |
48 | ␊ |
49 | void chainLoad();␊ |
50 | void waitThenReload();␊ |
51 | ␊ |
52 | // Starts off in the multiboot context 1 MB high but eventually gets into low memory␊ |
53 | // and winds up with a bootdevice in eax which is all that boot() wants␊ |
54 | // This lets the stack pointer remain very high.␊ |
55 | // If we were to call boot directly from multiboot then the whole multiboot_info␊ |
56 | // would be on the stack which would possibly be using way too much stack.␊ |
57 | void multiboot_to_boot(int multiboot_magic, struct multiboot_info *mi_orig)␊ |
58 | {␊ |
59 | uint32_t bootdevice = hi_multiboot(multiboot_magic, mi_orig);␊ |
60 | if(bootdevice != BAD_BOOT_DEVICE)␊ |
61 | {␊ |
62 | // boot only returns to do a chain load.␊ |
63 | for(;;)␊ |
64 | { // NOTE: boot only uses the last byte (the drive number)␊ |
65 | common_boot(bootdevice);␊ |
66 | if(chainbootflag)␊ |
67 | chainLoad();␊ |
68 | else␊ |
69 | waitThenReload();␊ |
70 | }␊ |
71 | }␊ |
72 | // Avoid returning to high-memory address which isn't valid in the segment␊ |
73 | // we are now in.␊ |
74 | // Calling sleep() ensures the user ought to be able to use Ctrl+Alt+Del␊ |
75 | // because the BIOS will have interrupts on.␊ |
76 | for(;;)␊ |
77 | sleep(10);␊ |
78 | // NOTE: *IF* we needed to return we'd have to fix up our return address to␊ |
79 | // be in low memory using the same trick as below.␊ |
80 | // However, there doesn't seem to be any point in returning to assembly␊ |
81 | // particularly when the remaining code merely halts the processor.␊ |
82 | }␊ |
83 | ␊ |
84 | void chainLoad()␊ |
85 | {␊ |
86 | /* TODO: We ought to load the appropriate partition table, for example␊ |
87 | the MBR if booting a primary partition or the particular extended␊ |
88 | partition table if booting a logical drive. For example, the␊ |
89 | regular MS MBR booter will relocate itself (e.g. the MBR) from␊ |
90 | 0:7C00 to 0:0600 and will use SI as the offset when reading␊ |
91 | the partition data from itself. Thus when it jumps to the partition␊ |
92 | boot sector, SI will be 0x600 + 446 + i<<4 where i is the partition␊ |
93 | table index.␊ |
94 | ␊ |
95 | On the other hand, our code for the non-Multiboot case doesn't do␊ |
96 | this either, although GRUB does.␊ |
97 | */␊ |
98 | ␊ |
99 | const unsigned char *bootcode = (const unsigned char*)0x7c00;␊ |
100 | if(bootcode[0x1fe] == 0x55 && bootcode[0x1ff] == 0xaa)␊ |
101 | {␊ |
102 | printf("Calling chainbooter\n");␊ |
103 | jump_to_chainbooter();␊ |
104 | /* NORETURN */␊ |
105 | }␊ |
106 | else␊ |
107 | {␊ |
108 | printf("Bad chain boot sector magic: %02x%02x\n", bootcode[0x1fe], bootcode[0x1ff]);␊ |
109 | }␊ |
110 | }␊ |
111 | ␊ |
112 | void waitThenReload()␊ |
113 | {␊ |
114 | /* FIXME: Ctrl+Alt+Del does not work under Boot Camp */␊ |
115 | ␉uint8_t i = 5;␊ |
116 | printf("Darwin booter exited for some reason.\n");␊ |
117 | printf("Please reboot (Ctrl+Alt+Del) your machine.\n");␊ |
118 | printf("Restarting Darwin booter in %d seconds...",i);␊ |
119 | sleep(1);␉␊ |
120 | ␉while (1 < i--) {␊ |
121 | ␉␉printf("%d...",i);␊ |
122 | ␉␉sleep(1);␊ |
123 | ␉}␊ |
124 | ␉printf("0\n");␊ |
125 | }␊ |
126 | ␊ |
127 | // Declare boot2_sym as an opaque struct so it can't be converted to a pointer␊ |
128 | // i.e. ensure the idiot programmer (me) makes sure to use address-of␊ |
129 | // Technically it's a function but it's real mode code and we sure don't␊ |
130 | // want to call it under any circumstances.␊ |
131 | extern struct {} boot2_sym asm("boot2");␊ |
132 | ␊ |
133 | // prototype multiboot and keep its implementation below hi_multiboot to␊ |
134 | // ensure that it doesn't get inlined by the compiler␊ |
135 | static inline uint32_t multiboot(int multiboot_magic, struct multiboot_info *mi);␊ |
136 | ␊ |
137 | ␊ |
138 | /*!␊ |
139 | Returns a pointer to the first safe address we can use for stowing the multiboot info.␊ |
140 | This might actually be a bit pedantic because mboot.c32 and GRUB both stow the multiboot␊ |
141 | info in low memory meaning that the >= 128 MB location we choose is plenty high enough.␊ |
142 | */␊ |
143 | void *determine_safe_hi_addr(int multiboot_magic, struct multiboot_info *mi_orig)␊ |
144 | {␊ |
145 | // hi_addr must be at least up in 128MB+ space so it doesn't get clobbered␊ |
146 | void *hi_addr = (void*)PREBOOT_DATA;␊ |
147 | ␊ |
148 | // Fail if the magic isn't correct. We'll complain later.␊ |
149 | if(multiboot_magic != MULTIBOOT_INFO_MAGIC)␊ |
150 | return NULL;␊ |
151 | // Make sure the command-line isn't in high memory.␊ |
152 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊ |
153 | {␊ |
154 | char *end = mi_orig->mi_cmdline;␊ |
155 | if(end != NULL)␊ |
156 | {␊ |
157 | for(; *end != '\0'; ++end)␊ |
158 | ;␊ |
159 | ++end;␊ |
160 | if( (void*)end > hi_addr)␊ |
161 | hi_addr = end;␊ |
162 | }␊ |
163 | }␊ |
164 | // Make sure the module information isn't in high memory␊ |
165 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_MODS)␊ |
166 | {␊ |
167 | struct multiboot_module *modules = (void*)mi_orig->mi_mods_addr;␊ |
168 | uint32_t i;␊ |
169 | for(i=0; i < mi_orig->mi_mods_count; ++i)␊ |
170 | {␊ |
171 | // make sure the multiboot_module struct itself won't get clobbered␊ |
172 | void *modinfo_end = modules+i+1;␊ |
173 | if(modinfo_end > hi_addr)␊ |
174 | hi_addr = modinfo_end;␊ |
175 | // make sure the module itself won't get clobbered␊ |
176 | modinfo_end = (void*)modules[i].mm_mod_end;␊ |
177 | if(modinfo_end > hi_addr)␊ |
178 | hi_addr = modinfo_end;␊ |
179 | // make sure the module string doesn't get clobbered␊ |
180 | char *end = modules[i].mm_string;␊ |
181 | for(; *end != '\0'; ++end)␊ |
182 | ;␊ |
183 | ++end;␊ |
184 | modinfo_end = end;␊ |
185 | if(modinfo_end > hi_addr)␊ |
186 | hi_addr = modinfo_end;␊ |
187 | }␊ |
188 | }␊ |
189 | // TODO: Copy syms (never needed), mmap, drives, config table, loader name, apm table, VBE info␊ |
190 | ␊ |
191 | // Round up to page size␊ |
192 | hi_addr = (void*)(((uint32_t)hi_addr + 0xfff) & ~(uint32_t)0xfff);␊ |
193 | return hi_addr;␊ |
194 | }␊ |
195 | ␊ |
196 | /*!␊ |
197 | Like malloc but with a preceding input/output parameter which points to the next available␊ |
198 | location for data. The original value of *hi_addr is returned and *hi_addr is incremented␊ |
199 | by size bytes.␊ |
200 | */␊ |
201 | void * _hi_malloc(void **hi_addr, size_t size)␊ |
202 | {␊ |
203 | void *ret = *hi_addr;␊ |
204 | *hi_addr += size;␊ |
205 | return ret;␊ |
206 | }␊ |
207 | ␊ |
208 | /*!␊ |
209 | Like strdup but with a preceding input/output parameter. The original value of *hi_addr is␊ |
210 | returned and *hi_addr is incremented by the number of bytes necessary to complete the string␊ |
211 | copy including its NUL terminator.␊ |
212 | */␊ |
213 | char * _hi_strdup(void **hi_addr, char *src)␊ |
214 | {␊ |
215 | char *dstStart;␊ |
216 | char *dst = dstStart = *hi_addr;␊ |
217 | for(; *src != '\0'; ++src, ++dst, ++(*hi_addr))␊ |
218 | *dst = *src;␊ |
219 | *dst = '\0';␊ |
220 | ++(*hi_addr);␊ |
221 | return dstStart;␊ |
222 | }␊ |
223 | ␊ |
224 | // Convenience macros␊ |
225 | #define hi_malloc(size) _hi_malloc(&hi_addr, (size))␊ |
226 | #define hi_strdup(src) _hi_strdup(&hi_addr, (src))␊ |
227 | ␊ |
228 | /*!␊ |
229 | Copies the Multiboot info and any associated data (e.g. various strings and any multiboot modules)␊ |
230 | up to very high RAM (above 128 MB) to ensure it doesn't get clobbered by the booter.␊ |
231 | */␊ |
232 | struct multiboot_info * copyMultibootInfo(int multiboot_magic, struct multiboot_info *mi_orig)␊ |
233 | {␊ |
234 | void *hi_addr = determine_safe_hi_addr(multiboot_magic, mi_orig);␊ |
235 | if(hi_addr == NULL)␊ |
236 | return NULL;␊ |
237 | ␊ |
238 | struct multiboot_info *mi_copy = hi_malloc(sizeof(*mi_copy));␊ |
239 | memcpy(mi_copy, mi_orig, sizeof(*mi_copy));␊ |
240 | ␊ |
241 | // Copy the command line␊ |
242 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊ |
243 | {␊ |
244 | mi_copy->mi_cmdline = hi_strdup(mi_orig->mi_cmdline);␊ |
245 | }␊ |
246 | // Copy the loader name␊ |
247 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_LOADER_NAME)␊ |
248 | {␊ |
249 | mi_copy->mi_loader_name = hi_strdup(mi_orig->mi_loader_name);␊ |
250 | }␊ |
251 | // Copy the module info␊ |
252 | if(mi_orig->mi_flags & MULTIBOOT_INFO_HAS_MODS)␊ |
253 | {␊ |
254 | struct multiboot_module *dst_modules = hi_malloc(sizeof(*dst_modules)*mi_orig->mi_mods_count);␊ |
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 | /* Zero the BSS and initialize malloc */␊ |
312 | initialize_runtime();␊ |
313 | ␊ |
314 | gMI = mi_p;␊ |
315 | ␊ |
316 | /* Set up a temporary bootArgs so we can call console output routines␊ |
317 | like printf that check the v_display. Note that we purposefully␊ |
318 | do not initialize anything else at this early stage.␊ |
319 | ␊ |
320 | We are reasonably sure we're already in text mode if GRUB booted us.␊ |
321 | This is the same assumption that initKernBootStruct makes.␊ |
322 | We could check the multiboot info I guess, but why bother?␊ |
323 | */␊ |
324 | boot_args temporaryBootArgsData;␊ |
325 | bzero(&temporaryBootArgsData, sizeof(boot_args));␊ |
326 | bootArgs = &temporaryBootArgsData;␊ |
327 | bootArgs->Video.v_display = VGA_TEXT_MODE;␊ |
328 | ␊ |
329 | ␊ |
330 | // Since we call multiboot ourselves, its return address will be correct.␊ |
331 | // That is unless it's inlined in which case it does not matter.␊ |
332 | uint32_t bootdevice = multiboot(multiboot_magic, mi_p);␊ |
333 | // We're about to exit and temporaryBootArgs will no longer be valid␊ |
334 | bootArgs = NULL;␊ |
335 | return bootdevice;␊ |
336 | }␊ |
337 | ␊ |
338 | // This is the meat of our implementation. It grabs the boot device from␊ |
339 | // the multiboot_info and returns it as is. If it fails it returns␊ |
340 | // BAD_BOOT_DEVICE. We can call an awful lot of libsa and libsaio but␊ |
341 | // we need to take care not to call anything that requires malloc because␊ |
342 | // it won't be initialized until boot() does it.␊ |
343 | static inline uint32_t multiboot(int multiboot_magic, struct multiboot_info *mi)␊ |
344 | {␊ |
345 | if(multiboot_magic != MULTIBOOT_INFO_MAGIC)␊ |
346 | {␊ |
347 | printf("Wrong Multiboot magic\n");␊ |
348 | sleep(2);␊ |
349 | return BAD_BOOT_DEVICE;␊ |
350 | }␊ |
351 | printf("Multiboot info @0x%x\n", (uint32_t)mi);␊ |
352 | if(mi->mi_flags & MULTIBOOT_INFO_HAS_LOADER_NAME)␊ |
353 | printf("Loaded by %s\n", mi->mi_loader_name);␊ |
354 | ␊ |
355 | // Multiboot puts boot device in high byte␊ |
356 | // Normal booter wants it in low byte␊ |
357 | uint32_t bootdevice = mi->mi_boot_device_drive;␊ |
358 | ␊ |
359 | //bool doSelectDevice = false;␊ |
360 | if(mi->mi_flags & MULTIBOOT_INFO_HAS_BOOT_DEVICE)␊ |
361 | {␊ |
362 | printf("Boot device 0x%x\n", bootdevice);␊ |
363 | }␊ |
364 | else␊ |
365 | {␊ |
366 | printf("Multiboot info does not include chosen boot device\n");␊ |
367 | //doSelectDevice = true;␊ |
368 | bootdevice = BAD_BOOT_DEVICE;␊ |
369 | }␊ |
370 | if(mi->mi_flags & MULTIBOOT_INFO_HAS_CMDLINE)␊ |
371 | {␊ |
372 | const char *val;␊ |
373 | int size;␊ |
374 | ␊ |
375 | if(getValueForBootKey(mi->mi_cmdline, "biosdev", &val, &size))␊ |
376 | {␊ |
377 | char *endptr;␊ |
378 | int intVal = strtol(val, &endptr, 16 /* always hex */);␊ |
379 | if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊ |
380 | {␊ |
381 | printf("Boot device overridden to %02x with biosdev=%s\n", intVal, val);␊ |
382 | bootdevice = intVal;␊ |
383 | //doSelectDevice = false;␊ |
384 | }␊ |
385 | //else␊ |
386 | // doSelectDevice = true;␊ |
387 | }␊ |
388 | #if UNUSED␉␉␊ |
389 | if(getValueForBootKey(mi->mi_cmdline, "timeout", &val, &size))␊ |
390 | {␊ |
391 | char *endptr;␊ |
392 | int intVal = strtol(val, &endptr, 0);␊ |
393 | if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊ |
394 | {␊ |
395 | printf("Timeout overridden to %d with timeout=%s\n", intVal, val);␊ |
396 | multiboot_timeout = intVal;␊ |
397 | multiboot_timeout_set = 1;␊ |
398 | }␊ |
399 | }␉␉␊ |
400 | ␉␉␊ |
401 | if(getValueForBootKey(mi->mi_cmdline, "partno", &val, &size))␊ |
402 | {␊ |
403 | char *endptr;␊ |
404 | int intVal = strtol(val, &endptr, 0);␊ |
405 | if(*val != '\0' && (*endptr == '\0' || *endptr == ' ' || *endptr == '\t'))␊ |
406 | {␊ |
407 | printf("Default partition overridden to %d with timeout=%s\n", intVal, val);␊ |
408 | multiboot_partition = intVal;␊ |
409 | multiboot_partition_set = 1;␊ |
410 | }␊ |
411 | }␊ |
412 | #endif␊ |
413 | }␊ |
414 | if(bootdevice == BAD_BOOT_DEVICE)␊ |
415 | sleep(2); // pause for a second before halting␊ |
416 | return bootdevice;␊ |
417 | }␊ |
418 | |