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84778508 BS |
1 | /* |
2 | * mmap support for qemu | |
3 | * | |
4 | * Copyright (c) 2003 - 2008 Fabrice Bellard | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to the Free Software | |
18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
19 | */ | |
20 | #include <stdlib.h> | |
21 | #include <stdio.h> | |
22 | #include <stdarg.h> | |
23 | #include <string.h> | |
24 | #include <unistd.h> | |
25 | #include <errno.h> | |
26 | #include <sys/mman.h> | |
27 | ||
28 | #include "qemu.h" | |
29 | #include "qemu-common.h" | |
6c173b3c | 30 | #include "bsd-mman.h" |
84778508 BS |
31 | |
32 | //#define DEBUG_MMAP | |
33 | ||
34 | #if defined(USE_NPTL) | |
35 | pthread_mutex_t mmap_mutex; | |
36 | static int __thread mmap_lock_count; | |
37 | ||
38 | void mmap_lock(void) | |
39 | { | |
40 | if (mmap_lock_count++ == 0) { | |
41 | pthread_mutex_lock(&mmap_mutex); | |
42 | } | |
43 | } | |
44 | ||
45 | void mmap_unlock(void) | |
46 | { | |
47 | if (--mmap_lock_count == 0) { | |
48 | pthread_mutex_unlock(&mmap_mutex); | |
49 | } | |
50 | } | |
51 | ||
52 | /* Grab lock to make sure things are in a consistent state after fork(). */ | |
53 | void mmap_fork_start(void) | |
54 | { | |
55 | if (mmap_lock_count) | |
56 | abort(); | |
57 | pthread_mutex_lock(&mmap_mutex); | |
58 | } | |
59 | ||
60 | void mmap_fork_end(int child) | |
61 | { | |
62 | if (child) | |
63 | pthread_mutex_init(&mmap_mutex, NULL); | |
64 | else | |
65 | pthread_mutex_unlock(&mmap_mutex); | |
66 | } | |
67 | #else | |
68 | /* We aren't threadsafe to start with, so no need to worry about locking. */ | |
69 | void mmap_lock(void) | |
70 | { | |
71 | } | |
72 | ||
73 | void mmap_unlock(void) | |
74 | { | |
75 | } | |
76 | #endif | |
77 | ||
78 | void *qemu_vmalloc(size_t size) | |
79 | { | |
80 | void *p; | |
81 | unsigned long addr; | |
82 | mmap_lock(); | |
83 | /* Use map and mark the pages as used. */ | |
84 | p = mmap(NULL, size, PROT_READ | PROT_WRITE, | |
85 | MAP_PRIVATE | MAP_ANON, -1, 0); | |
86 | ||
87 | addr = (unsigned long)p; | |
88 | if (addr == (target_ulong) addr) { | |
89 | /* Allocated region overlaps guest address space. | |
90 | This may recurse. */ | |
91 | page_set_flags(addr & TARGET_PAGE_MASK, TARGET_PAGE_ALIGN(addr + size), | |
92 | PAGE_RESERVED); | |
93 | } | |
94 | ||
95 | mmap_unlock(); | |
96 | return p; | |
97 | } | |
98 | ||
99 | void *qemu_malloc(size_t size) | |
100 | { | |
101 | char * p; | |
102 | size += 16; | |
103 | p = qemu_vmalloc(size); | |
104 | *(size_t *)p = size; | |
105 | return p + 16; | |
106 | } | |
107 | ||
108 | /* We use map, which is always zero initialized. */ | |
109 | void * qemu_mallocz(size_t size) | |
110 | { | |
111 | return qemu_malloc(size); | |
112 | } | |
113 | ||
114 | void qemu_free(void *ptr) | |
115 | { | |
116 | /* FIXME: We should unmark the reserved pages here. However this gets | |
117 | complicated when one target page spans multiple host pages, so we | |
118 | don't bother. */ | |
119 | size_t *p; | |
120 | p = (size_t *)((char *)ptr - 16); | |
121 | munmap(p, *p); | |
122 | } | |
123 | ||
124 | /* NOTE: all the constants are the HOST ones, but addresses are target. */ | |
125 | int target_mprotect(abi_ulong start, abi_ulong len, int prot) | |
126 | { | |
127 | abi_ulong end, host_start, host_end, addr; | |
128 | int prot1, ret; | |
129 | ||
130 | #ifdef DEBUG_MMAP | |
131 | printf("mprotect: start=0x" TARGET_FMT_lx | |
132 | " len=0x" TARGET_FMT_lx " prot=%c%c%c\n", start, len, | |
133 | prot & PROT_READ ? 'r' : '-', | |
134 | prot & PROT_WRITE ? 'w' : '-', | |
135 | prot & PROT_EXEC ? 'x' : '-'); | |
136 | #endif | |
137 | ||
138 | if ((start & ~TARGET_PAGE_MASK) != 0) | |
139 | return -EINVAL; | |
140 | len = TARGET_PAGE_ALIGN(len); | |
141 | end = start + len; | |
142 | if (end < start) | |
143 | return -EINVAL; | |
144 | prot &= PROT_READ | PROT_WRITE | PROT_EXEC; | |
145 | if (len == 0) | |
146 | return 0; | |
147 | ||
148 | mmap_lock(); | |
149 | host_start = start & qemu_host_page_mask; | |
150 | host_end = HOST_PAGE_ALIGN(end); | |
151 | if (start > host_start) { | |
152 | /* handle host page containing start */ | |
153 | prot1 = prot; | |
154 | for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) { | |
155 | prot1 |= page_get_flags(addr); | |
156 | } | |
157 | if (host_end == host_start + qemu_host_page_size) { | |
158 | for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) { | |
159 | prot1 |= page_get_flags(addr); | |
160 | } | |
161 | end = host_end; | |
162 | } | |
163 | ret = mprotect(g2h(host_start), qemu_host_page_size, prot1 & PAGE_BITS); | |
164 | if (ret != 0) | |
165 | goto error; | |
166 | host_start += qemu_host_page_size; | |
167 | } | |
168 | if (end < host_end) { | |
169 | prot1 = prot; | |
170 | for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) { | |
171 | prot1 |= page_get_flags(addr); | |
172 | } | |
173 | ret = mprotect(g2h(host_end - qemu_host_page_size), qemu_host_page_size, | |
174 | prot1 & PAGE_BITS); | |
175 | if (ret != 0) | |
176 | goto error; | |
177 | host_end -= qemu_host_page_size; | |
178 | } | |
179 | ||
180 | /* handle the pages in the middle */ | |
181 | if (host_start < host_end) { | |
182 | ret = mprotect(g2h(host_start), host_end - host_start, prot); | |
183 | if (ret != 0) | |
184 | goto error; | |
185 | } | |
186 | page_set_flags(start, start + len, prot | PAGE_VALID); | |
187 | mmap_unlock(); | |
188 | return 0; | |
189 | error: | |
190 | mmap_unlock(); | |
191 | return ret; | |
192 | } | |
193 | ||
194 | /* map an incomplete host page */ | |
195 | static int mmap_frag(abi_ulong real_start, | |
196 | abi_ulong start, abi_ulong end, | |
197 | int prot, int flags, int fd, abi_ulong offset) | |
198 | { | |
199 | abi_ulong real_end, addr; | |
200 | void *host_start; | |
201 | int prot1, prot_new; | |
202 | ||
203 | real_end = real_start + qemu_host_page_size; | |
204 | host_start = g2h(real_start); | |
205 | ||
206 | /* get the protection of the target pages outside the mapping */ | |
207 | prot1 = 0; | |
208 | for(addr = real_start; addr < real_end; addr++) { | |
209 | if (addr < start || addr >= end) | |
210 | prot1 |= page_get_flags(addr); | |
211 | } | |
212 | ||
213 | if (prot1 == 0) { | |
214 | /* no page was there, so we allocate one */ | |
215 | void *p = mmap(host_start, qemu_host_page_size, prot, | |
216 | flags | MAP_ANON, -1, 0); | |
217 | if (p == MAP_FAILED) | |
218 | return -1; | |
219 | prot1 = prot; | |
220 | } | |
221 | prot1 &= PAGE_BITS; | |
222 | ||
223 | prot_new = prot | prot1; | |
224 | if (!(flags & MAP_ANON)) { | |
225 | /* msync() won't work here, so we return an error if write is | |
226 | possible while it is a shared mapping */ | |
6c173b3c | 227 | if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED && |
84778508 BS |
228 | (prot & PROT_WRITE)) |
229 | return -EINVAL; | |
230 | ||
231 | /* adjust protection to be able to read */ | |
232 | if (!(prot1 & PROT_WRITE)) | |
233 | mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE); | |
234 | ||
235 | /* read the corresponding file data */ | |
236 | pread(fd, g2h(start), end - start, offset); | |
237 | ||
238 | /* put final protection */ | |
239 | if (prot_new != (prot1 | PROT_WRITE)) | |
240 | mprotect(host_start, qemu_host_page_size, prot_new); | |
241 | } else { | |
242 | /* just update the protection */ | |
243 | if (prot_new != prot1) { | |
244 | mprotect(host_start, qemu_host_page_size, prot_new); | |
245 | } | |
246 | } | |
247 | return 0; | |
248 | } | |
249 | ||
250 | #if defined(__CYGWIN__) | |
251 | /* Cygwin doesn't have a whole lot of address space. */ | |
252 | static abi_ulong mmap_next_start = 0x18000000; | |
253 | #else | |
254 | static abi_ulong mmap_next_start = 0x40000000; | |
255 | #endif | |
256 | ||
257 | unsigned long last_brk; | |
258 | ||
259 | /* find a free memory area of size 'size'. The search starts at | |
260 | 'start'. If 'start' == 0, then a default start address is used. | |
261 | Return -1 if error. | |
262 | */ | |
263 | /* page_init() marks pages used by the host as reserved to be sure not | |
264 | to use them. */ | |
265 | static abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size) | |
266 | { | |
267 | abi_ulong addr, addr1, addr_start; | |
268 | int prot; | |
269 | unsigned long new_brk; | |
270 | ||
271 | new_brk = (unsigned long)sbrk(0); | |
272 | if (last_brk && last_brk < new_brk && last_brk == (target_ulong)last_brk) { | |
273 | /* This is a hack to catch the host allocating memory with brk(). | |
274 | If it uses mmap then we loose. | |
275 | FIXME: We really want to avoid the host allocating memory in | |
276 | the first place, and maybe leave some slack to avoid switching | |
277 | to mmap. */ | |
278 | page_set_flags(last_brk & TARGET_PAGE_MASK, | |
279 | TARGET_PAGE_ALIGN(new_brk), | |
280 | PAGE_RESERVED); | |
281 | } | |
282 | last_brk = new_brk; | |
283 | ||
284 | size = HOST_PAGE_ALIGN(size); | |
285 | start = start & qemu_host_page_mask; | |
286 | addr = start; | |
287 | if (addr == 0) | |
288 | addr = mmap_next_start; | |
289 | addr_start = addr; | |
290 | for(;;) { | |
291 | prot = 0; | |
292 | for(addr1 = addr; addr1 < (addr + size); addr1 += TARGET_PAGE_SIZE) { | |
293 | prot |= page_get_flags(addr1); | |
294 | } | |
295 | if (prot == 0) | |
296 | break; | |
297 | addr += qemu_host_page_size; | |
298 | /* we found nothing */ | |
299 | if (addr == addr_start) | |
300 | return (abi_ulong)-1; | |
301 | } | |
302 | if (start == 0) | |
303 | mmap_next_start = addr + size; | |
304 | return addr; | |
305 | } | |
306 | ||
307 | /* NOTE: all the constants are the HOST ones */ | |
308 | abi_long target_mmap(abi_ulong start, abi_ulong len, int prot, | |
309 | int flags, int fd, abi_ulong offset) | |
310 | { | |
311 | abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len; | |
312 | unsigned long host_start; | |
313 | ||
314 | mmap_lock(); | |
315 | #ifdef DEBUG_MMAP | |
316 | { | |
317 | printf("mmap: start=0x" TARGET_FMT_lx | |
318 | " len=0x" TARGET_FMT_lx " prot=%c%c%c flags=", | |
319 | start, len, | |
320 | prot & PROT_READ ? 'r' : '-', | |
321 | prot & PROT_WRITE ? 'w' : '-', | |
322 | prot & PROT_EXEC ? 'x' : '-'); | |
323 | if (flags & MAP_FIXED) | |
324 | printf("MAP_FIXED "); | |
325 | if (flags & MAP_ANON) | |
326 | printf("MAP_ANON "); | |
6c173b3c | 327 | switch(flags & TARGET_BSD_MAP_FLAGMASK) { |
84778508 BS |
328 | case MAP_PRIVATE: |
329 | printf("MAP_PRIVATE "); | |
330 | break; | |
331 | case MAP_SHARED: | |
332 | printf("MAP_SHARED "); | |
333 | break; | |
334 | default: | |
6c173b3c | 335 | printf("[MAP_FLAGMASK=0x%x] ", flags & TARGET_BSD_MAP_FLAGMASK); |
84778508 BS |
336 | break; |
337 | } | |
338 | printf("fd=%d offset=" TARGET_FMT_lx "\n", fd, offset); | |
339 | } | |
340 | #endif | |
341 | ||
342 | if (offset & ~TARGET_PAGE_MASK) { | |
343 | errno = EINVAL; | |
344 | goto fail; | |
345 | } | |
346 | ||
347 | len = TARGET_PAGE_ALIGN(len); | |
348 | if (len == 0) | |
349 | goto the_end; | |
350 | real_start = start & qemu_host_page_mask; | |
351 | ||
352 | if (!(flags & MAP_FIXED)) { | |
353 | abi_ulong mmap_start; | |
354 | void *p; | |
355 | host_offset = offset & qemu_host_page_mask; | |
356 | host_len = len + offset - host_offset; | |
357 | host_len = HOST_PAGE_ALIGN(host_len); | |
358 | mmap_start = mmap_find_vma(real_start, host_len); | |
359 | if (mmap_start == (abi_ulong)-1) { | |
360 | errno = ENOMEM; | |
361 | goto fail; | |
362 | } | |
363 | /* Note: we prefer to control the mapping address. It is | |
364 | especially important if qemu_host_page_size > | |
365 | qemu_real_host_page_size */ | |
366 | p = mmap(g2h(mmap_start), | |
367 | host_len, prot, flags | MAP_FIXED, fd, host_offset); | |
368 | if (p == MAP_FAILED) | |
369 | goto fail; | |
370 | /* update start so that it points to the file position at 'offset' */ | |
371 | host_start = (unsigned long)p; | |
372 | if (!(flags & MAP_ANON)) | |
373 | host_start += offset - host_offset; | |
374 | start = h2g(host_start); | |
375 | } else { | |
376 | int flg; | |
377 | target_ulong addr; | |
378 | ||
379 | if (start & ~TARGET_PAGE_MASK) { | |
380 | errno = EINVAL; | |
381 | goto fail; | |
382 | } | |
383 | end = start + len; | |
384 | real_end = HOST_PAGE_ALIGN(end); | |
385 | ||
386 | for(addr = real_start; addr < real_end; addr += TARGET_PAGE_SIZE) { | |
387 | flg = page_get_flags(addr); | |
388 | if (flg & PAGE_RESERVED) { | |
389 | errno = ENXIO; | |
390 | goto fail; | |
391 | } | |
392 | } | |
393 | ||
394 | /* worst case: we cannot map the file because the offset is not | |
395 | aligned, so we read it */ | |
396 | if (!(flags & MAP_ANON) && | |
397 | (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) { | |
398 | /* msync() won't work here, so we return an error if write is | |
399 | possible while it is a shared mapping */ | |
6c173b3c | 400 | if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED && |
84778508 BS |
401 | (prot & PROT_WRITE)) { |
402 | errno = EINVAL; | |
403 | goto fail; | |
404 | } | |
405 | retaddr = target_mmap(start, len, prot | PROT_WRITE, | |
406 | MAP_FIXED | MAP_PRIVATE | MAP_ANON, | |
407 | -1, 0); | |
408 | if (retaddr == -1) | |
409 | goto fail; | |
410 | pread(fd, g2h(start), len, offset); | |
411 | if (!(prot & PROT_WRITE)) { | |
412 | ret = target_mprotect(start, len, prot); | |
413 | if (ret != 0) { | |
414 | start = ret; | |
415 | goto the_end; | |
416 | } | |
417 | } | |
418 | goto the_end; | |
419 | } | |
420 | ||
421 | /* handle the start of the mapping */ | |
422 | if (start > real_start) { | |
423 | if (real_end == real_start + qemu_host_page_size) { | |
424 | /* one single host page */ | |
425 | ret = mmap_frag(real_start, start, end, | |
426 | prot, flags, fd, offset); | |
427 | if (ret == -1) | |
428 | goto fail; | |
429 | goto the_end1; | |
430 | } | |
431 | ret = mmap_frag(real_start, start, real_start + qemu_host_page_size, | |
432 | prot, flags, fd, offset); | |
433 | if (ret == -1) | |
434 | goto fail; | |
435 | real_start += qemu_host_page_size; | |
436 | } | |
437 | /* handle the end of the mapping */ | |
438 | if (end < real_end) { | |
439 | ret = mmap_frag(real_end - qemu_host_page_size, | |
440 | real_end - qemu_host_page_size, real_end, | |
441 | prot, flags, fd, | |
442 | offset + real_end - qemu_host_page_size - start); | |
443 | if (ret == -1) | |
444 | goto fail; | |
445 | real_end -= qemu_host_page_size; | |
446 | } | |
447 | ||
448 | /* map the middle (easier) */ | |
449 | if (real_start < real_end) { | |
450 | void *p; | |
451 | unsigned long offset1; | |
452 | if (flags & MAP_ANON) | |
453 | offset1 = 0; | |
454 | else | |
455 | offset1 = offset + real_start - start; | |
456 | p = mmap(g2h(real_start), real_end - real_start, | |
457 | prot, flags, fd, offset1); | |
458 | if (p == MAP_FAILED) | |
459 | goto fail; | |
460 | } | |
461 | } | |
462 | the_end1: | |
463 | page_set_flags(start, start + len, prot | PAGE_VALID); | |
464 | the_end: | |
465 | #ifdef DEBUG_MMAP | |
466 | printf("ret=0x" TARGET_FMT_lx "\n", start); | |
467 | page_dump(stdout); | |
468 | printf("\n"); | |
469 | #endif | |
470 | mmap_unlock(); | |
471 | return start; | |
472 | fail: | |
473 | mmap_unlock(); | |
474 | return -1; | |
475 | } | |
476 | ||
477 | int target_munmap(abi_ulong start, abi_ulong len) | |
478 | { | |
479 | abi_ulong end, real_start, real_end, addr; | |
480 | int prot, ret; | |
481 | ||
482 | #ifdef DEBUG_MMAP | |
483 | printf("munmap: start=0x%lx len=0x%lx\n", start, len); | |
484 | #endif | |
485 | if (start & ~TARGET_PAGE_MASK) | |
486 | return -EINVAL; | |
487 | len = TARGET_PAGE_ALIGN(len); | |
488 | if (len == 0) | |
489 | return -EINVAL; | |
490 | mmap_lock(); | |
491 | end = start + len; | |
492 | real_start = start & qemu_host_page_mask; | |
493 | real_end = HOST_PAGE_ALIGN(end); | |
494 | ||
495 | if (start > real_start) { | |
496 | /* handle host page containing start */ | |
497 | prot = 0; | |
498 | for(addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) { | |
499 | prot |= page_get_flags(addr); | |
500 | } | |
501 | if (real_end == real_start + qemu_host_page_size) { | |
502 | for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { | |
503 | prot |= page_get_flags(addr); | |
504 | } | |
505 | end = real_end; | |
506 | } | |
507 | if (prot != 0) | |
508 | real_start += qemu_host_page_size; | |
509 | } | |
510 | if (end < real_end) { | |
511 | prot = 0; | |
512 | for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { | |
513 | prot |= page_get_flags(addr); | |
514 | } | |
515 | if (prot != 0) | |
516 | real_end -= qemu_host_page_size; | |
517 | } | |
518 | ||
519 | ret = 0; | |
520 | /* unmap what we can */ | |
521 | if (real_start < real_end) { | |
522 | ret = munmap(g2h(real_start), real_end - real_start); | |
523 | } | |
524 | ||
525 | if (ret == 0) | |
526 | page_set_flags(start, start + len, 0); | |
527 | mmap_unlock(); | |
528 | return ret; | |
529 | } | |
530 | ||
531 | int target_msync(abi_ulong start, abi_ulong len, int flags) | |
532 | { | |
533 | abi_ulong end; | |
534 | ||
535 | if (start & ~TARGET_PAGE_MASK) | |
536 | return -EINVAL; | |
537 | len = TARGET_PAGE_ALIGN(len); | |
538 | end = start + len; | |
539 | if (end < start) | |
540 | return -EINVAL; | |
541 | if (end == start) | |
542 | return 0; | |
543 | ||
544 | start &= qemu_host_page_mask; | |
545 | return msync(g2h(start), end - start, flags); | |
546 | } |