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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" |
05757c5d | 24 | #include "exec/exec-all.h" |
84778508 BS |
25 | |
26 | //#define DEBUG_MMAP | |
27 | ||
95992b67 | 28 | static pthread_mutex_t mmap_mutex = PTHREAD_MUTEX_INITIALIZER; |
06943a62 | 29 | static __thread int mmap_lock_count; |
84778508 BS |
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 | } | |
84778508 | 65 | |
84778508 BS |
66 | /* NOTE: all the constants are the HOST ones, but addresses are target. */ |
67 | int target_mprotect(abi_ulong start, abi_ulong len, int prot) | |
68 | { | |
69 | abi_ulong end, host_start, host_end, addr; | |
70 | int prot1, ret; | |
71 | ||
72 | #ifdef DEBUG_MMAP | |
73 | printf("mprotect: start=0x" TARGET_FMT_lx | |
74 | " len=0x" TARGET_FMT_lx " prot=%c%c%c\n", start, len, | |
75 | prot & PROT_READ ? 'r' : '-', | |
76 | prot & PROT_WRITE ? 'w' : '-', | |
77 | prot & PROT_EXEC ? 'x' : '-'); | |
78 | #endif | |
79 | ||
80 | if ((start & ~TARGET_PAGE_MASK) != 0) | |
81 | return -EINVAL; | |
82 | len = TARGET_PAGE_ALIGN(len); | |
83 | end = start + len; | |
84 | if (end < start) | |
85 | return -EINVAL; | |
86 | prot &= PROT_READ | PROT_WRITE | PROT_EXEC; | |
87 | if (len == 0) | |
88 | return 0; | |
89 | ||
90 | mmap_lock(); | |
91 | host_start = start & qemu_host_page_mask; | |
92 | host_end = HOST_PAGE_ALIGN(end); | |
93 | if (start > host_start) { | |
94 | /* handle host page containing start */ | |
95 | prot1 = prot; | |
96 | for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) { | |
97 | prot1 |= page_get_flags(addr); | |
98 | } | |
99 | if (host_end == host_start + qemu_host_page_size) { | |
100 | for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) { | |
101 | prot1 |= page_get_flags(addr); | |
102 | } | |
103 | end = host_end; | |
104 | } | |
3e8f1628 RH |
105 | ret = mprotect(g2h_untagged(host_start), |
106 | qemu_host_page_size, prot1 & PAGE_BITS); | |
84778508 BS |
107 | if (ret != 0) |
108 | goto error; | |
109 | host_start += qemu_host_page_size; | |
110 | } | |
111 | if (end < host_end) { | |
112 | prot1 = prot; | |
113 | for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) { | |
114 | prot1 |= page_get_flags(addr); | |
115 | } | |
3e8f1628 RH |
116 | ret = mprotect(g2h_untagged(host_end - qemu_host_page_size), |
117 | qemu_host_page_size, prot1 & PAGE_BITS); | |
84778508 BS |
118 | if (ret != 0) |
119 | goto error; | |
120 | host_end -= qemu_host_page_size; | |
121 | } | |
122 | ||
123 | /* handle the pages in the middle */ | |
124 | if (host_start < host_end) { | |
3e8f1628 | 125 | ret = mprotect(g2h_untagged(host_start), host_end - host_start, prot); |
84778508 BS |
126 | if (ret != 0) |
127 | goto error; | |
128 | } | |
129 | page_set_flags(start, start + len, prot | PAGE_VALID); | |
130 | mmap_unlock(); | |
131 | return 0; | |
132 | error: | |
133 | mmap_unlock(); | |
134 | return ret; | |
135 | } | |
136 | ||
137 | /* map an incomplete host page */ | |
138 | static int mmap_frag(abi_ulong real_start, | |
139 | abi_ulong start, abi_ulong end, | |
140 | int prot, int flags, int fd, abi_ulong offset) | |
141 | { | |
142 | abi_ulong real_end, addr; | |
143 | void *host_start; | |
144 | int prot1, prot_new; | |
145 | ||
146 | real_end = real_start + qemu_host_page_size; | |
3e8f1628 | 147 | host_start = g2h_untagged(real_start); |
84778508 BS |
148 | |
149 | /* get the protection of the target pages outside the mapping */ | |
150 | prot1 = 0; | |
151 | for(addr = real_start; addr < real_end; addr++) { | |
152 | if (addr < start || addr >= end) | |
153 | prot1 |= page_get_flags(addr); | |
154 | } | |
155 | ||
156 | if (prot1 == 0) { | |
157 | /* no page was there, so we allocate one */ | |
158 | void *p = mmap(host_start, qemu_host_page_size, prot, | |
159 | flags | MAP_ANON, -1, 0); | |
160 | if (p == MAP_FAILED) | |
161 | return -1; | |
162 | prot1 = prot; | |
163 | } | |
164 | prot1 &= PAGE_BITS; | |
165 | ||
166 | prot_new = prot | prot1; | |
167 | if (!(flags & MAP_ANON)) { | |
168 | /* msync() won't work here, so we return an error if write is | |
169 | possible while it is a shared mapping */ | |
6c173b3c | 170 | if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED && |
84778508 | 171 | (prot & PROT_WRITE)) |
059bca46 | 172 | return -1; |
84778508 BS |
173 | |
174 | /* adjust protection to be able to read */ | |
175 | if (!(prot1 & PROT_WRITE)) | |
176 | mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE); | |
177 | ||
178 | /* read the corresponding file data */ | |
3e8f1628 | 179 | pread(fd, g2h_untagged(start), end - start, offset); |
84778508 BS |
180 | |
181 | /* put final protection */ | |
182 | if (prot_new != (prot1 | PROT_WRITE)) | |
183 | mprotect(host_start, qemu_host_page_size, prot_new); | |
184 | } else { | |
185 | /* just update the protection */ | |
186 | if (prot_new != prot1) { | |
187 | mprotect(host_start, qemu_host_page_size, prot_new); | |
188 | } | |
189 | } | |
190 | return 0; | |
191 | } | |
192 | ||
84778508 | 193 | static abi_ulong mmap_next_start = 0x40000000; |
84778508 BS |
194 | |
195 | unsigned long last_brk; | |
196 | ||
197 | /* find a free memory area of size 'size'. The search starts at | |
198 | 'start'. If 'start' == 0, then a default start address is used. | |
199 | Return -1 if error. | |
200 | */ | |
201 | /* page_init() marks pages used by the host as reserved to be sure not | |
202 | to use them. */ | |
203 | static abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size) | |
204 | { | |
205 | abi_ulong addr, addr1, addr_start; | |
206 | int prot; | |
207 | unsigned long new_brk; | |
208 | ||
209 | new_brk = (unsigned long)sbrk(0); | |
210 | if (last_brk && last_brk < new_brk && last_brk == (target_ulong)last_brk) { | |
211 | /* This is a hack to catch the host allocating memory with brk(). | |
212 | If it uses mmap then we loose. | |
213 | FIXME: We really want to avoid the host allocating memory in | |
214 | the first place, and maybe leave some slack to avoid switching | |
215 | to mmap. */ | |
216 | page_set_flags(last_brk & TARGET_PAGE_MASK, | |
217 | TARGET_PAGE_ALIGN(new_brk), | |
218 | PAGE_RESERVED); | |
219 | } | |
220 | last_brk = new_brk; | |
221 | ||
222 | size = HOST_PAGE_ALIGN(size); | |
223 | start = start & qemu_host_page_mask; | |
224 | addr = start; | |
225 | if (addr == 0) | |
226 | addr = mmap_next_start; | |
227 | addr_start = addr; | |
228 | for(;;) { | |
229 | prot = 0; | |
230 | for(addr1 = addr; addr1 < (addr + size); addr1 += TARGET_PAGE_SIZE) { | |
231 | prot |= page_get_flags(addr1); | |
232 | } | |
233 | if (prot == 0) | |
234 | break; | |
235 | addr += qemu_host_page_size; | |
236 | /* we found nothing */ | |
237 | if (addr == addr_start) | |
238 | return (abi_ulong)-1; | |
239 | } | |
240 | if (start == 0) | |
241 | mmap_next_start = addr + size; | |
242 | return addr; | |
243 | } | |
244 | ||
245 | /* NOTE: all the constants are the HOST ones */ | |
246 | abi_long target_mmap(abi_ulong start, abi_ulong len, int prot, | |
247 | int flags, int fd, abi_ulong offset) | |
248 | { | |
249 | abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len; | |
250 | unsigned long host_start; | |
251 | ||
252 | mmap_lock(); | |
253 | #ifdef DEBUG_MMAP | |
254 | { | |
255 | printf("mmap: start=0x" TARGET_FMT_lx | |
256 | " len=0x" TARGET_FMT_lx " prot=%c%c%c flags=", | |
257 | start, len, | |
258 | prot & PROT_READ ? 'r' : '-', | |
259 | prot & PROT_WRITE ? 'w' : '-', | |
260 | prot & PROT_EXEC ? 'x' : '-'); | |
261 | if (flags & MAP_FIXED) | |
262 | printf("MAP_FIXED "); | |
263 | if (flags & MAP_ANON) | |
264 | printf("MAP_ANON "); | |
6c173b3c | 265 | switch(flags & TARGET_BSD_MAP_FLAGMASK) { |
84778508 BS |
266 | case MAP_PRIVATE: |
267 | printf("MAP_PRIVATE "); | |
268 | break; | |
269 | case MAP_SHARED: | |
270 | printf("MAP_SHARED "); | |
271 | break; | |
272 | default: | |
6c173b3c | 273 | printf("[MAP_FLAGMASK=0x%x] ", flags & TARGET_BSD_MAP_FLAGMASK); |
84778508 BS |
274 | break; |
275 | } | |
276 | printf("fd=%d offset=" TARGET_FMT_lx "\n", fd, offset); | |
277 | } | |
278 | #endif | |
279 | ||
280 | if (offset & ~TARGET_PAGE_MASK) { | |
281 | errno = EINVAL; | |
282 | goto fail; | |
283 | } | |
284 | ||
285 | len = TARGET_PAGE_ALIGN(len); | |
286 | if (len == 0) | |
287 | goto the_end; | |
288 | real_start = start & qemu_host_page_mask; | |
289 | ||
290 | if (!(flags & MAP_FIXED)) { | |
291 | abi_ulong mmap_start; | |
292 | void *p; | |
293 | host_offset = offset & qemu_host_page_mask; | |
294 | host_len = len + offset - host_offset; | |
295 | host_len = HOST_PAGE_ALIGN(host_len); | |
296 | mmap_start = mmap_find_vma(real_start, host_len); | |
297 | if (mmap_start == (abi_ulong)-1) { | |
298 | errno = ENOMEM; | |
299 | goto fail; | |
300 | } | |
301 | /* Note: we prefer to control the mapping address. It is | |
302 | especially important if qemu_host_page_size > | |
303 | qemu_real_host_page_size */ | |
3e8f1628 | 304 | p = mmap(g2h_untagged(mmap_start), |
84778508 BS |
305 | host_len, prot, flags | MAP_FIXED, fd, host_offset); |
306 | if (p == MAP_FAILED) | |
307 | goto fail; | |
308 | /* update start so that it points to the file position at 'offset' */ | |
309 | host_start = (unsigned long)p; | |
310 | if (!(flags & MAP_ANON)) | |
311 | host_start += offset - host_offset; | |
312 | start = h2g(host_start); | |
313 | } else { | |
314 | int flg; | |
315 | target_ulong addr; | |
316 | ||
317 | if (start & ~TARGET_PAGE_MASK) { | |
318 | errno = EINVAL; | |
319 | goto fail; | |
320 | } | |
321 | end = start + len; | |
322 | real_end = HOST_PAGE_ALIGN(end); | |
323 | ||
324 | for(addr = real_start; addr < real_end; addr += TARGET_PAGE_SIZE) { | |
325 | flg = page_get_flags(addr); | |
326 | if (flg & PAGE_RESERVED) { | |
327 | errno = ENXIO; | |
328 | goto fail; | |
329 | } | |
330 | } | |
331 | ||
332 | /* worst case: we cannot map the file because the offset is not | |
333 | aligned, so we read it */ | |
334 | if (!(flags & MAP_ANON) && | |
335 | (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) { | |
336 | /* msync() won't work here, so we return an error if write is | |
337 | possible while it is a shared mapping */ | |
6c173b3c | 338 | if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED && |
84778508 BS |
339 | (prot & PROT_WRITE)) { |
340 | errno = EINVAL; | |
341 | goto fail; | |
342 | } | |
343 | retaddr = target_mmap(start, len, prot | PROT_WRITE, | |
344 | MAP_FIXED | MAP_PRIVATE | MAP_ANON, | |
345 | -1, 0); | |
346 | if (retaddr == -1) | |
347 | goto fail; | |
3e8f1628 | 348 | pread(fd, g2h_untagged(start), len, offset); |
84778508 BS |
349 | if (!(prot & PROT_WRITE)) { |
350 | ret = target_mprotect(start, len, prot); | |
351 | if (ret != 0) { | |
352 | start = ret; | |
353 | goto the_end; | |
354 | } | |
355 | } | |
356 | goto the_end; | |
357 | } | |
358 | ||
359 | /* handle the start of the mapping */ | |
360 | if (start > real_start) { | |
361 | if (real_end == real_start + qemu_host_page_size) { | |
362 | /* one single host page */ | |
363 | ret = mmap_frag(real_start, start, end, | |
364 | prot, flags, fd, offset); | |
365 | if (ret == -1) | |
366 | goto fail; | |
367 | goto the_end1; | |
368 | } | |
369 | ret = mmap_frag(real_start, start, real_start + qemu_host_page_size, | |
370 | prot, flags, fd, offset); | |
371 | if (ret == -1) | |
372 | goto fail; | |
373 | real_start += qemu_host_page_size; | |
374 | } | |
375 | /* handle the end of the mapping */ | |
376 | if (end < real_end) { | |
377 | ret = mmap_frag(real_end - qemu_host_page_size, | |
378 | real_end - qemu_host_page_size, real_end, | |
379 | prot, flags, fd, | |
380 | offset + real_end - qemu_host_page_size - start); | |
381 | if (ret == -1) | |
382 | goto fail; | |
383 | real_end -= qemu_host_page_size; | |
384 | } | |
385 | ||
386 | /* map the middle (easier) */ | |
387 | if (real_start < real_end) { | |
388 | void *p; | |
389 | unsigned long offset1; | |
390 | if (flags & MAP_ANON) | |
391 | offset1 = 0; | |
392 | else | |
393 | offset1 = offset + real_start - start; | |
3e8f1628 | 394 | p = mmap(g2h_untagged(real_start), real_end - real_start, |
84778508 BS |
395 | prot, flags, fd, offset1); |
396 | if (p == MAP_FAILED) | |
397 | goto fail; | |
398 | } | |
399 | } | |
400 | the_end1: | |
401 | page_set_flags(start, start + len, prot | PAGE_VALID); | |
402 | the_end: | |
403 | #ifdef DEBUG_MMAP | |
404 | printf("ret=0x" TARGET_FMT_lx "\n", start); | |
405 | page_dump(stdout); | |
406 | printf("\n"); | |
407 | #endif | |
408 | mmap_unlock(); | |
409 | return start; | |
410 | fail: | |
411 | mmap_unlock(); | |
412 | return -1; | |
413 | } | |
414 | ||
415 | int target_munmap(abi_ulong start, abi_ulong len) | |
416 | { | |
417 | abi_ulong end, real_start, real_end, addr; | |
418 | int prot, ret; | |
419 | ||
420 | #ifdef DEBUG_MMAP | |
421 | printf("munmap: start=0x%lx len=0x%lx\n", start, len); | |
422 | #endif | |
423 | if (start & ~TARGET_PAGE_MASK) | |
424 | return -EINVAL; | |
425 | len = TARGET_PAGE_ALIGN(len); | |
426 | if (len == 0) | |
427 | return -EINVAL; | |
428 | mmap_lock(); | |
429 | end = start + len; | |
430 | real_start = start & qemu_host_page_mask; | |
431 | real_end = HOST_PAGE_ALIGN(end); | |
432 | ||
433 | if (start > real_start) { | |
434 | /* handle host page containing start */ | |
435 | prot = 0; | |
436 | for(addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) { | |
437 | prot |= page_get_flags(addr); | |
438 | } | |
439 | if (real_end == real_start + qemu_host_page_size) { | |
440 | for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { | |
441 | prot |= page_get_flags(addr); | |
442 | } | |
443 | end = real_end; | |
444 | } | |
445 | if (prot != 0) | |
446 | real_start += qemu_host_page_size; | |
447 | } | |
448 | if (end < real_end) { | |
449 | prot = 0; | |
450 | for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { | |
451 | prot |= page_get_flags(addr); | |
452 | } | |
453 | if (prot != 0) | |
454 | real_end -= qemu_host_page_size; | |
455 | } | |
456 | ||
457 | ret = 0; | |
458 | /* unmap what we can */ | |
459 | if (real_start < real_end) { | |
3e8f1628 | 460 | ret = munmap(g2h_untagged(real_start), real_end - real_start); |
84778508 BS |
461 | } |
462 | ||
463 | if (ret == 0) | |
464 | page_set_flags(start, start + len, 0); | |
465 | mmap_unlock(); | |
466 | return ret; | |
467 | } | |
468 | ||
469 | int target_msync(abi_ulong start, abi_ulong len, int flags) | |
470 | { | |
471 | abi_ulong end; | |
472 | ||
473 | if (start & ~TARGET_PAGE_MASK) | |
474 | return -EINVAL; | |
475 | len = TARGET_PAGE_ALIGN(len); | |
476 | end = start + len; | |
477 | if (end < start) | |
478 | return -EINVAL; | |
479 | if (end == start) | |
480 | return 0; | |
481 | ||
482 | start &= qemu_host_page_mask; | |
3e8f1628 | 483 | return msync(g2h_untagged(start), end - start, flags); |
84778508 | 484 | } |