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