2 * mmap support for qemu
4 * Copyright (c) 2003 Fabrice Bellard
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.
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.
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.
32 /* NOTE: all the constants are the HOST ones, but addresses are target. */
33 int target_mprotect(target_ulong start
, target_ulong len
, int prot
)
35 target_ulong end
, host_start
, host_end
, addr
;
39 printf("mprotect: start=0x" TARGET_FMT_lx
40 "len=0x" TARGET_FMT_lx
" prot=%c%c%c\n", start
, len
,
41 prot
& PROT_READ
? 'r' : '-',
42 prot
& PROT_WRITE
? 'w' : '-',
43 prot
& PROT_EXEC
? 'x' : '-');
46 if ((start
& ~TARGET_PAGE_MASK
) != 0)
48 len
= TARGET_PAGE_ALIGN(len
);
52 if (prot
& ~(PROT_READ
| PROT_WRITE
| PROT_EXEC
))
57 host_start
= start
& qemu_host_page_mask
;
58 host_end
= HOST_PAGE_ALIGN(end
);
59 if (start
> host_start
) {
60 /* handle host page containing start */
62 for(addr
= host_start
; addr
< start
; addr
+= TARGET_PAGE_SIZE
) {
63 prot1
|= page_get_flags(addr
);
65 if (host_end
== host_start
+ qemu_host_page_size
) {
66 for(addr
= end
; addr
< host_end
; addr
+= TARGET_PAGE_SIZE
) {
67 prot1
|= page_get_flags(addr
);
71 ret
= mprotect(g2h(host_start
), qemu_host_page_size
, prot1
& PAGE_BITS
);
74 host_start
+= qemu_host_page_size
;
78 for(addr
= end
; addr
< host_end
; addr
+= TARGET_PAGE_SIZE
) {
79 prot1
|= page_get_flags(addr
);
81 ret
= mprotect(g2h(host_end
- qemu_host_page_size
), qemu_host_page_size
,
85 host_end
-= qemu_host_page_size
;
88 /* handle the pages in the middle */
89 if (host_start
< host_end
) {
90 ret
= mprotect(g2h(host_start
), host_end
- host_start
, prot
);
94 page_set_flags(start
, start
+ len
, prot
| PAGE_VALID
);
98 /* map an incomplete host page */
99 static int mmap_frag(target_ulong real_start
,
100 target_ulong start
, target_ulong end
,
101 int prot
, int flags
, int fd
, target_ulong offset
)
103 target_ulong real_end
, ret
, addr
;
107 real_end
= real_start
+ qemu_host_page_size
;
108 host_start
= g2h(real_start
);
110 /* get the protection of the target pages outside the mapping */
112 for(addr
= real_start
; addr
< real_end
; addr
++) {
113 if (addr
< start
|| addr
>= end
)
114 prot1
|= page_get_flags(addr
);
118 /* no page was there, so we allocate one */
119 ret
= (long)mmap(host_start
, qemu_host_page_size
, prot
,
120 flags
| MAP_ANONYMOUS
, -1, 0);
127 prot_new
= prot
| prot1
;
128 if (!(flags
& MAP_ANONYMOUS
)) {
129 /* msync() won't work here, so we return an error if write is
130 possible while it is a shared mapping */
131 if ((flags
& MAP_TYPE
) == MAP_SHARED
&&
135 /* adjust protection to be able to read */
136 if (!(prot1
& PROT_WRITE
))
137 mprotect(host_start
, qemu_host_page_size
, prot1
| PROT_WRITE
);
139 /* read the corresponding file data */
140 pread(fd
, g2h(start
), end
- start
, offset
);
142 /* put final protection */
143 if (prot_new
!= (prot1
| PROT_WRITE
))
144 mprotect(host_start
, qemu_host_page_size
, prot_new
);
146 /* just update the protection */
147 if (prot_new
!= prot1
) {
148 mprotect(host_start
, qemu_host_page_size
, prot_new
);
154 /* NOTE: all the constants are the HOST ones */
155 target_long
target_mmap(target_ulong start
, target_ulong len
, int prot
,
156 int flags
, int fd
, target_ulong offset
)
158 target_ulong ret
, end
, real_start
, real_end
, retaddr
, host_offset
, host_len
;
159 unsigned long host_start
;
160 #if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__) || \
161 defined(__ia64) || defined(__mips__)
162 static target_ulong last_start
= 0x40000000;
163 #elif defined(__CYGWIN__)
164 /* Cygwin doesn't have a whole lot of address space. */
165 static target_ulong last_start
= 0x18000000;
170 printf("mmap: start=0x" TARGET_FMT_lx
171 " len=0x" TARGET_FMT_lx
" prot=%c%c%c flags=",
173 prot
& PROT_READ
? 'r' : '-',
174 prot
& PROT_WRITE
? 'w' : '-',
175 prot
& PROT_EXEC
? 'x' : '-');
176 if (flags
& MAP_FIXED
)
177 printf("MAP_FIXED ");
178 if (flags
& MAP_ANONYMOUS
)
180 switch(flags
& MAP_TYPE
) {
182 printf("MAP_PRIVATE ");
185 printf("MAP_SHARED ");
188 printf("[MAP_TYPE=0x%x] ", flags
& MAP_TYPE
);
191 printf("fd=%d offset=" TARGET_FMT_lx
"\n", fd
, offset
);
195 if (offset
& ~TARGET_PAGE_MASK
) {
200 len
= TARGET_PAGE_ALIGN(len
);
203 real_start
= start
& qemu_host_page_mask
;
205 if (!(flags
& MAP_FIXED
)) {
206 #if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__) || \
207 defined(__ia64) || defined(__mips__) || defined(__CYGWIN__)
208 /* tell the kernel to search at the same place as i386 */
209 if (real_start
== 0) {
210 real_start
= last_start
;
211 last_start
+= HOST_PAGE_ALIGN(len
);
214 host_offset
= offset
& qemu_host_page_mask
;
215 host_len
= len
+ offset
- host_offset
;
217 if (qemu_host_page_size
> qemu_real_host_page_size
) {
219 * The guest expects to see mmapped areas aligned to it's pagesize.
220 * If the host's real page size is smaller than the guest's, we need
221 * to fixup the maps. It is done by allocating a larger area,
222 * displacing the map (if needed) and finally chopping off the spare
227 * We assume qemu_host_page_size is always the same as
228 * TARGET_PAGE_SIZE, see exec.c. qemu_real_host_page_size is the
229 * hosts real page size.
231 target_ulong host_end
;
232 unsigned long host_aligned_start
;
234 host_len
= HOST_PAGE_ALIGN(host_len
+ qemu_host_page_size
235 - qemu_real_host_page_size
);
236 host_start
= (unsigned long) mmap(real_start
?
237 g2h(real_start
) : NULL
,
238 host_len
, prot
, flags
,
240 if (host_start
== -1)
243 host_end
= host_start
+ host_len
;
245 /* Find start and end, aligned to the targets pagesize with-in the
246 large mmaped area. */
247 host_aligned_start
= TARGET_PAGE_ALIGN(host_start
);
248 if (!(flags
& MAP_ANONYMOUS
))
249 host_aligned_start
+= offset
- host_offset
;
251 start
= h2g(host_aligned_start
);
252 end
= start
+ TARGET_PAGE_ALIGN(len
);
254 /* Chop off the leftovers, if any. */
255 if (host_aligned_start
> host_start
)
256 munmap((void *)host_start
, host_aligned_start
- host_start
);
258 munmap((void *)g2h(end
), host_end
- end
);
262 /* if not fixed, no need to do anything */
263 host_start
= (long)mmap(real_start
? g2h(real_start
) : NULL
,
264 host_len
, prot
, flags
, fd
, host_offset
);
265 if (host_start
== -1)
267 /* update start so that it points to the file position at 'offset' */
268 if (!(flags
& MAP_ANONYMOUS
))
269 host_start
+= offset
- host_offset
;
270 start
= h2g(host_start
);
275 if (start
& ~TARGET_PAGE_MASK
) {
280 real_end
= HOST_PAGE_ALIGN(end
);
282 /* worst case: we cannot map the file because the offset is not
283 aligned, so we read it */
284 if (!(flags
& MAP_ANONYMOUS
) &&
285 (offset
& ~qemu_host_page_mask
) != (start
& ~qemu_host_page_mask
)) {
286 /* msync() won't work here, so we return an error if write is
287 possible while it is a shared mapping */
288 if ((flags
& MAP_TYPE
) == MAP_SHARED
&&
289 (prot
& PROT_WRITE
)) {
293 retaddr
= target_mmap(start
, len
, prot
| PROT_WRITE
,
294 MAP_FIXED
| MAP_PRIVATE
| MAP_ANONYMOUS
,
298 pread(fd
, g2h(start
), len
, offset
);
299 if (!(prot
& PROT_WRITE
)) {
300 ret
= target_mprotect(start
, len
, prot
);
307 /* handle the start of the mapping */
308 if (start
> real_start
) {
309 if (real_end
== real_start
+ qemu_host_page_size
) {
310 /* one single host page */
311 ret
= mmap_frag(real_start
, start
, end
,
312 prot
, flags
, fd
, offset
);
317 ret
= mmap_frag(real_start
, start
, real_start
+ qemu_host_page_size
,
318 prot
, flags
, fd
, offset
);
321 real_start
+= qemu_host_page_size
;
323 /* handle the end of the mapping */
324 if (end
< real_end
) {
325 ret
= mmap_frag(real_end
- qemu_host_page_size
,
326 real_end
- qemu_host_page_size
, real_end
,
328 offset
+ real_end
- qemu_host_page_size
- start
);
331 real_end
-= qemu_host_page_size
;
334 /* map the middle (easier) */
335 if (real_start
< real_end
) {
336 unsigned long offset1
;
337 if (flags
& MAP_ANONYMOUS
)
340 offset1
= offset
+ real_start
- start
;
341 ret
= (long)mmap(g2h(real_start
), real_end
- real_start
,
342 prot
, flags
, fd
, offset1
);
347 page_set_flags(start
, start
+ len
, prot
| PAGE_VALID
);
350 printf("ret=0x%llx\n", start
);
357 int target_munmap(target_ulong start
, target_ulong len
)
359 target_ulong end
, real_start
, real_end
, addr
;
363 printf("munmap: start=0x%lx len=0x%lx\n", start
, len
);
365 if (start
& ~TARGET_PAGE_MASK
)
367 len
= TARGET_PAGE_ALIGN(len
);
371 real_start
= start
& qemu_host_page_mask
;
372 real_end
= HOST_PAGE_ALIGN(end
);
374 if (start
> real_start
) {
375 /* handle host page containing start */
377 for(addr
= real_start
; addr
< start
; addr
+= TARGET_PAGE_SIZE
) {
378 prot
|= page_get_flags(addr
);
380 if (real_end
== real_start
+ qemu_host_page_size
) {
381 for(addr
= end
; addr
< real_end
; addr
+= TARGET_PAGE_SIZE
) {
382 prot
|= page_get_flags(addr
);
387 real_start
+= qemu_host_page_size
;
389 if (end
< real_end
) {
391 for(addr
= end
; addr
< real_end
; addr
+= TARGET_PAGE_SIZE
) {
392 prot
|= page_get_flags(addr
);
395 real_end
-= qemu_host_page_size
;
398 /* unmap what we can */
399 if (real_start
< real_end
) {
400 ret
= munmap(g2h(real_start
), real_end
- real_start
);
405 page_set_flags(start
, start
+ len
, 0);
409 /* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED
410 blocks which have been allocated starting on a host page */
411 target_long
target_mremap(target_ulong old_addr
, target_ulong old_size
,
412 target_ulong new_size
, unsigned long flags
,
413 target_ulong new_addr
)
416 unsigned long host_addr
;
418 /* XXX: use 5 args syscall */
419 host_addr
= (long)mremap(g2h(old_addr
), old_size
, new_size
, flags
);
422 new_addr
= h2g(host_addr
);
423 prot
= page_get_flags(old_addr
);
424 page_set_flags(old_addr
, old_addr
+ old_size
, 0);
425 page_set_flags(new_addr
, new_addr
+ new_size
, prot
| PAGE_VALID
);
429 int target_msync(target_ulong start
, target_ulong len
, int flags
)
433 if (start
& ~TARGET_PAGE_MASK
)
435 len
= TARGET_PAGE_ALIGN(len
);
442 start
&= qemu_host_page_mask
;
443 return msync(g2h(start
), end
- start
, flags
);