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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 | |
8167ee88 | 17 | * along with this program; if not, see <http://www.gnu.org/licenses/>. |
84778508 | 18 | */ |
2231197c | 19 | #include "qemu/osdep.h" |
84778508 BS |
20 | |
21 | #include "qemu.h" | |
22 | #include "qemu-common.h" | |
6c173b3c | 23 | #include "bsd-mman.h" |
84778508 BS |
24 | |
25 | //#define DEBUG_MMAP | |
26 | ||
2f7bb878 | 27 | #if defined(CONFIG_USE_NPTL) |
84778508 BS |
28 | pthread_mutex_t mmap_mutex; |
29 | static int __thread mmap_lock_count; | |
30 | ||
31 | void mmap_lock(void) | |
32 | { | |
33 | if (mmap_lock_count++ == 0) { | |
34 | pthread_mutex_lock(&mmap_mutex); | |
35 | } | |
36 | } | |
37 | ||
38 | void mmap_unlock(void) | |
39 | { | |
40 | if (--mmap_lock_count == 0) { | |
41 | pthread_mutex_unlock(&mmap_mutex); | |
42 | } | |
43 | } | |
44 | ||
301e40ed AB |
45 | bool have_mmap_lock(void) |
46 | { | |
47 | return mmap_lock_count > 0 ? true : false; | |
48 | } | |
49 | ||
84778508 BS |
50 | /* Grab lock to make sure things are in a consistent state after fork(). */ |
51 | void mmap_fork_start(void) | |
52 | { | |
53 | if (mmap_lock_count) | |
54 | abort(); | |
55 | pthread_mutex_lock(&mmap_mutex); | |
56 | } | |
57 | ||
58 | void mmap_fork_end(int child) | |
59 | { | |
60 | if (child) | |
61 | pthread_mutex_init(&mmap_mutex, NULL); | |
62 | else | |
63 | pthread_mutex_unlock(&mmap_mutex); | |
64 | } | |
65 | #else | |
66 | /* We aren't threadsafe to start with, so no need to worry about locking. */ | |
67 | void mmap_lock(void) | |
68 | { | |
69 | } | |
70 | ||
71 | void mmap_unlock(void) | |
72 | { | |
73 | } | |
74 | #endif | |
75 | ||
84778508 BS |
76 | /* NOTE: all the constants are the HOST ones, but addresses are target. */ |
77 | int target_mprotect(abi_ulong start, abi_ulong len, int prot) | |
78 | { | |
79 | abi_ulong end, host_start, host_end, addr; | |
80 | int prot1, ret; | |
81 | ||
82 | #ifdef DEBUG_MMAP | |
83 | printf("mprotect: start=0x" TARGET_FMT_lx | |
84 | " len=0x" TARGET_FMT_lx " prot=%c%c%c\n", start, len, | |
85 | prot & PROT_READ ? 'r' : '-', | |
86 | prot & PROT_WRITE ? 'w' : '-', | |
87 | prot & PROT_EXEC ? 'x' : '-'); | |
88 | #endif | |
89 | ||
90 | if ((start & ~TARGET_PAGE_MASK) != 0) | |
91 | return -EINVAL; | |
92 | len = TARGET_PAGE_ALIGN(len); | |
93 | end = start + len; | |
94 | if (end < start) | |
95 | return -EINVAL; | |
96 | prot &= PROT_READ | PROT_WRITE | PROT_EXEC; | |
97 | if (len == 0) | |
98 | return 0; | |
99 | ||
100 | mmap_lock(); | |
101 | host_start = start & qemu_host_page_mask; | |
102 | host_end = HOST_PAGE_ALIGN(end); | |
103 | if (start > host_start) { | |
104 | /* handle host page containing start */ | |
105 | prot1 = prot; | |
106 | for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) { | |
107 | prot1 |= page_get_flags(addr); | |
108 | } | |
109 | if (host_end == host_start + qemu_host_page_size) { | |
110 | for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) { | |
111 | prot1 |= page_get_flags(addr); | |
112 | } | |
113 | end = host_end; | |
114 | } | |
115 | ret = mprotect(g2h(host_start), qemu_host_page_size, prot1 & PAGE_BITS); | |
116 | if (ret != 0) | |
117 | goto error; | |
118 | host_start += qemu_host_page_size; | |
119 | } | |
120 | if (end < host_end) { | |
121 | prot1 = prot; | |
122 | for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) { | |
123 | prot1 |= page_get_flags(addr); | |
124 | } | |
125 | ret = mprotect(g2h(host_end - qemu_host_page_size), qemu_host_page_size, | |
126 | prot1 & PAGE_BITS); | |
127 | if (ret != 0) | |
128 | goto error; | |
129 | host_end -= qemu_host_page_size; | |
130 | } | |
131 | ||
132 | /* handle the pages in the middle */ | |
133 | if (host_start < host_end) { | |
134 | ret = mprotect(g2h(host_start), host_end - host_start, prot); | |
135 | if (ret != 0) | |
136 | goto error; | |
137 | } | |
138 | page_set_flags(start, start + len, prot | PAGE_VALID); | |
139 | mmap_unlock(); | |
140 | return 0; | |
141 | error: | |
142 | mmap_unlock(); | |
143 | return ret; | |
144 | } | |
145 | ||
146 | /* map an incomplete host page */ | |
147 | static int mmap_frag(abi_ulong real_start, | |
148 | abi_ulong start, abi_ulong end, | |
149 | int prot, int flags, int fd, abi_ulong offset) | |
150 | { | |
151 | abi_ulong real_end, addr; | |
152 | void *host_start; | |
153 | int prot1, prot_new; | |
154 | ||
155 | real_end = real_start + qemu_host_page_size; | |
156 | host_start = g2h(real_start); | |
157 | ||
158 | /* get the protection of the target pages outside the mapping */ | |
159 | prot1 = 0; | |
160 | for(addr = real_start; addr < real_end; addr++) { | |
161 | if (addr < start || addr >= end) | |
162 | prot1 |= page_get_flags(addr); | |
163 | } | |
164 | ||
165 | if (prot1 == 0) { | |
166 | /* no page was there, so we allocate one */ | |
167 | void *p = mmap(host_start, qemu_host_page_size, prot, | |
168 | flags | MAP_ANON, -1, 0); | |
169 | if (p == MAP_FAILED) | |
170 | return -1; | |
171 | prot1 = prot; | |
172 | } | |
173 | prot1 &= PAGE_BITS; | |
174 | ||
175 | prot_new = prot | prot1; | |
176 | if (!(flags & MAP_ANON)) { | |
177 | /* msync() won't work here, so we return an error if write is | |
178 | possible while it is a shared mapping */ | |
6c173b3c | 179 | if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED && |
84778508 | 180 | (prot & PROT_WRITE)) |
059bca46 | 181 | return -1; |
84778508 BS |
182 | |
183 | /* adjust protection to be able to read */ | |
184 | if (!(prot1 & PROT_WRITE)) | |
185 | mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE); | |
186 | ||
187 | /* read the corresponding file data */ | |
188 | pread(fd, g2h(start), end - start, offset); | |
189 | ||
190 | /* put final protection */ | |
191 | if (prot_new != (prot1 | PROT_WRITE)) | |
192 | mprotect(host_start, qemu_host_page_size, prot_new); | |
193 | } else { | |
194 | /* just update the protection */ | |
195 | if (prot_new != prot1) { | |
196 | mprotect(host_start, qemu_host_page_size, prot_new); | |
197 | } | |
198 | } | |
199 | return 0; | |
200 | } | |
201 | ||
202 | #if defined(__CYGWIN__) | |
203 | /* Cygwin doesn't have a whole lot of address space. */ | |
204 | static abi_ulong mmap_next_start = 0x18000000; | |
205 | #else | |
206 | static abi_ulong mmap_next_start = 0x40000000; | |
207 | #endif | |
208 | ||
209 | unsigned long last_brk; | |
210 | ||
211 | /* find a free memory area of size 'size'. The search starts at | |
212 | 'start'. If 'start' == 0, then a default start address is used. | |
213 | Return -1 if error. | |
214 | */ | |
215 | /* page_init() marks pages used by the host as reserved to be sure not | |
216 | to use them. */ | |
217 | static abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size) | |
218 | { | |
219 | abi_ulong addr, addr1, addr_start; | |
220 | int prot; | |
221 | unsigned long new_brk; | |
222 | ||
223 | new_brk = (unsigned long)sbrk(0); | |
224 | if (last_brk && last_brk < new_brk && last_brk == (target_ulong)last_brk) { | |
225 | /* This is a hack to catch the host allocating memory with brk(). | |
226 | If it uses mmap then we loose. | |
227 | FIXME: We really want to avoid the host allocating memory in | |
228 | the first place, and maybe leave some slack to avoid switching | |
229 | to mmap. */ | |
230 | page_set_flags(last_brk & TARGET_PAGE_MASK, | |
231 | TARGET_PAGE_ALIGN(new_brk), | |
232 | PAGE_RESERVED); | |
233 | } | |
234 | last_brk = new_brk; | |
235 | ||
236 | size = HOST_PAGE_ALIGN(size); | |
237 | start = start & qemu_host_page_mask; | |
238 | addr = start; | |
239 | if (addr == 0) | |
240 | addr = mmap_next_start; | |
241 | addr_start = addr; | |
242 | for(;;) { | |
243 | prot = 0; | |
244 | for(addr1 = addr; addr1 < (addr + size); addr1 += TARGET_PAGE_SIZE) { | |
245 | prot |= page_get_flags(addr1); | |
246 | } | |
247 | if (prot == 0) | |
248 | break; | |
249 | addr += qemu_host_page_size; | |
250 | /* we found nothing */ | |
251 | if (addr == addr_start) | |
252 | return (abi_ulong)-1; | |
253 | } | |
254 | if (start == 0) | |
255 | mmap_next_start = addr + size; | |
256 | return addr; | |
257 | } | |
258 | ||
259 | /* NOTE: all the constants are the HOST ones */ | |
260 | abi_long target_mmap(abi_ulong start, abi_ulong len, int prot, | |
261 | int flags, int fd, abi_ulong offset) | |
262 | { | |
263 | abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len; | |
264 | unsigned long host_start; | |
265 | ||
266 | mmap_lock(); | |
267 | #ifdef DEBUG_MMAP | |
268 | { | |
269 | printf("mmap: start=0x" TARGET_FMT_lx | |
270 | " len=0x" TARGET_FMT_lx " prot=%c%c%c flags=", | |
271 | start, len, | |
272 | prot & PROT_READ ? 'r' : '-', | |
273 | prot & PROT_WRITE ? 'w' : '-', | |
274 | prot & PROT_EXEC ? 'x' : '-'); | |
275 | if (flags & MAP_FIXED) | |
276 | printf("MAP_FIXED "); | |
277 | if (flags & MAP_ANON) | |
278 | printf("MAP_ANON "); | |
6c173b3c | 279 | switch(flags & TARGET_BSD_MAP_FLAGMASK) { |
84778508 BS |
280 | case MAP_PRIVATE: |
281 | printf("MAP_PRIVATE "); | |
282 | break; | |
283 | case MAP_SHARED: | |
284 | printf("MAP_SHARED "); | |
285 | break; | |
286 | default: | |
6c173b3c | 287 | printf("[MAP_FLAGMASK=0x%x] ", flags & TARGET_BSD_MAP_FLAGMASK); |
84778508 BS |
288 | break; |
289 | } | |
290 | printf("fd=%d offset=" TARGET_FMT_lx "\n", fd, offset); | |
291 | } | |
292 | #endif | |
293 | ||
294 | if (offset & ~TARGET_PAGE_MASK) { | |
295 | errno = EINVAL; | |
296 | goto fail; | |
297 | } | |
298 | ||
299 | len = TARGET_PAGE_ALIGN(len); | |
300 | if (len == 0) | |
301 | goto the_end; | |
302 | real_start = start & qemu_host_page_mask; | |
303 | ||
304 | if (!(flags & MAP_FIXED)) { | |
305 | abi_ulong mmap_start; | |
306 | void *p; | |
307 | host_offset = offset & qemu_host_page_mask; | |
308 | host_len = len + offset - host_offset; | |
309 | host_len = HOST_PAGE_ALIGN(host_len); | |
310 | mmap_start = mmap_find_vma(real_start, host_len); | |
311 | if (mmap_start == (abi_ulong)-1) { | |
312 | errno = ENOMEM; | |
313 | goto fail; | |
314 | } | |
315 | /* Note: we prefer to control the mapping address. It is | |
316 | especially important if qemu_host_page_size > | |
317 | qemu_real_host_page_size */ | |
318 | p = mmap(g2h(mmap_start), | |
319 | host_len, prot, flags | MAP_FIXED, fd, host_offset); | |
320 | if (p == MAP_FAILED) | |
321 | goto fail; | |
322 | /* update start so that it points to the file position at 'offset' */ | |
323 | host_start = (unsigned long)p; | |
324 | if (!(flags & MAP_ANON)) | |
325 | host_start += offset - host_offset; | |
326 | start = h2g(host_start); | |
327 | } else { | |
328 | int flg; | |
329 | target_ulong addr; | |
330 | ||
331 | if (start & ~TARGET_PAGE_MASK) { | |
332 | errno = EINVAL; | |
333 | goto fail; | |
334 | } | |
335 | end = start + len; | |
336 | real_end = HOST_PAGE_ALIGN(end); | |
337 | ||
338 | for(addr = real_start; addr < real_end; addr += TARGET_PAGE_SIZE) { | |
339 | flg = page_get_flags(addr); | |
340 | if (flg & PAGE_RESERVED) { | |
341 | errno = ENXIO; | |
342 | goto fail; | |
343 | } | |
344 | } | |
345 | ||
346 | /* worst case: we cannot map the file because the offset is not | |
347 | aligned, so we read it */ | |
348 | if (!(flags & MAP_ANON) && | |
349 | (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) { | |
350 | /* msync() won't work here, so we return an error if write is | |
351 | possible while it is a shared mapping */ | |
6c173b3c | 352 | if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED && |
84778508 BS |
353 | (prot & PROT_WRITE)) { |
354 | errno = EINVAL; | |
355 | goto fail; | |
356 | } | |
357 | retaddr = target_mmap(start, len, prot | PROT_WRITE, | |
358 | MAP_FIXED | MAP_PRIVATE | MAP_ANON, | |
359 | -1, 0); | |
360 | if (retaddr == -1) | |
361 | goto fail; | |
362 | pread(fd, g2h(start), len, offset); | |
363 | if (!(prot & PROT_WRITE)) { | |
364 | ret = target_mprotect(start, len, prot); | |
365 | if (ret != 0) { | |
366 | start = ret; | |
367 | goto the_end; | |
368 | } | |
369 | } | |
370 | goto the_end; | |
371 | } | |
372 | ||
373 | /* handle the start of the mapping */ | |
374 | if (start > real_start) { | |
375 | if (real_end == real_start + qemu_host_page_size) { | |
376 | /* one single host page */ | |
377 | ret = mmap_frag(real_start, start, end, | |
378 | prot, flags, fd, offset); | |
379 | if (ret == -1) | |
380 | goto fail; | |
381 | goto the_end1; | |
382 | } | |
383 | ret = mmap_frag(real_start, start, real_start + qemu_host_page_size, | |
384 | prot, flags, fd, offset); | |
385 | if (ret == -1) | |
386 | goto fail; | |
387 | real_start += qemu_host_page_size; | |
388 | } | |
389 | /* handle the end of the mapping */ | |
390 | if (end < real_end) { | |
391 | ret = mmap_frag(real_end - qemu_host_page_size, | |
392 | real_end - qemu_host_page_size, real_end, | |
393 | prot, flags, fd, | |
394 | offset + real_end - qemu_host_page_size - start); | |
395 | if (ret == -1) | |
396 | goto fail; | |
397 | real_end -= qemu_host_page_size; | |
398 | } | |
399 | ||
400 | /* map the middle (easier) */ | |
401 | if (real_start < real_end) { | |
402 | void *p; | |
403 | unsigned long offset1; | |
404 | if (flags & MAP_ANON) | |
405 | offset1 = 0; | |
406 | else | |
407 | offset1 = offset + real_start - start; | |
408 | p = mmap(g2h(real_start), real_end - real_start, | |
409 | prot, flags, fd, offset1); | |
410 | if (p == MAP_FAILED) | |
411 | goto fail; | |
412 | } | |
413 | } | |
414 | the_end1: | |
415 | page_set_flags(start, start + len, prot | PAGE_VALID); | |
416 | the_end: | |
417 | #ifdef DEBUG_MMAP | |
418 | printf("ret=0x" TARGET_FMT_lx "\n", start); | |
419 | page_dump(stdout); | |
420 | printf("\n"); | |
421 | #endif | |
422 | mmap_unlock(); | |
423 | return start; | |
424 | fail: | |
425 | mmap_unlock(); | |
426 | return -1; | |
427 | } | |
428 | ||
429 | int target_munmap(abi_ulong start, abi_ulong len) | |
430 | { | |
431 | abi_ulong end, real_start, real_end, addr; | |
432 | int prot, ret; | |
433 | ||
434 | #ifdef DEBUG_MMAP | |
435 | printf("munmap: start=0x%lx len=0x%lx\n", start, len); | |
436 | #endif | |
437 | if (start & ~TARGET_PAGE_MASK) | |
438 | return -EINVAL; | |
439 | len = TARGET_PAGE_ALIGN(len); | |
440 | if (len == 0) | |
441 | return -EINVAL; | |
442 | mmap_lock(); | |
443 | end = start + len; | |
444 | real_start = start & qemu_host_page_mask; | |
445 | real_end = HOST_PAGE_ALIGN(end); | |
446 | ||
447 | if (start > real_start) { | |
448 | /* handle host page containing start */ | |
449 | prot = 0; | |
450 | for(addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) { | |
451 | prot |= page_get_flags(addr); | |
452 | } | |
453 | if (real_end == real_start + qemu_host_page_size) { | |
454 | for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { | |
455 | prot |= page_get_flags(addr); | |
456 | } | |
457 | end = real_end; | |
458 | } | |
459 | if (prot != 0) | |
460 | real_start += qemu_host_page_size; | |
461 | } | |
462 | if (end < real_end) { | |
463 | prot = 0; | |
464 | for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { | |
465 | prot |= page_get_flags(addr); | |
466 | } | |
467 | if (prot != 0) | |
468 | real_end -= qemu_host_page_size; | |
469 | } | |
470 | ||
471 | ret = 0; | |
472 | /* unmap what we can */ | |
473 | if (real_start < real_end) { | |
474 | ret = munmap(g2h(real_start), real_end - real_start); | |
475 | } | |
476 | ||
477 | if (ret == 0) | |
478 | page_set_flags(start, start + len, 0); | |
479 | mmap_unlock(); | |
480 | return ret; | |
481 | } | |
482 | ||
483 | int target_msync(abi_ulong start, abi_ulong len, int flags) | |
484 | { | |
485 | abi_ulong end; | |
486 | ||
487 | if (start & ~TARGET_PAGE_MASK) | |
488 | return -EINVAL; | |
489 | len = TARGET_PAGE_ALIGN(len); | |
490 | end = start + len; | |
491 | if (end < start) | |
492 | return -EINVAL; | |
493 | if (end == start) | |
494 | return 0; | |
495 | ||
496 | start &= qemu_host_page_mask; | |
497 | return msync(g2h(start), end - start, flags); | |
498 | } |