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1.1 root 1: /*
2: * mmap support for qemu
3: *
4: * Copyright (c) 2003 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:
30: //#define DEBUG_MMAP
31:
32: /* NOTE: all the constants are the HOST ones */
33: int target_mprotect(unsigned long start, unsigned long len, int prot)
34: {
35: unsigned long end, host_start, host_end, addr;
36: int prot1, ret;
37:
38: #ifdef DEBUG_MMAP
39: printf("mprotect: start=0x%lx len=0x%lx prot=%c%c%c\n", start, len,
40: prot & PROT_READ ? 'r' : '-',
41: prot & PROT_WRITE ? 'w' : '-',
42: prot & PROT_EXEC ? 'x' : '-');
43: #endif
44:
45: if ((start & ~TARGET_PAGE_MASK) != 0)
46: return -EINVAL;
47: len = TARGET_PAGE_ALIGN(len);
48: end = start + len;
49: if (end < start)
50: return -EINVAL;
51: if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC))
52: return -EINVAL;
53: if (len == 0)
54: return 0;
55:
56: host_start = start & qemu_host_page_mask;
57: host_end = HOST_PAGE_ALIGN(end);
58: if (start > host_start) {
59: /* handle host page containing start */
60: prot1 = prot;
61: for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
62: prot1 |= page_get_flags(addr);
63: }
64: if (host_end == host_start + qemu_host_page_size) {
65: for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
66: prot1 |= page_get_flags(addr);
67: }
68: end = host_end;
69: }
70: ret = mprotect((void *)host_start, qemu_host_page_size, prot1 & PAGE_BITS);
71: if (ret != 0)
72: return ret;
73: host_start += qemu_host_page_size;
74: }
75: if (end < host_end) {
76: prot1 = prot;
77: for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
78: prot1 |= page_get_flags(addr);
79: }
80: ret = mprotect((void *)(host_end - qemu_host_page_size), qemu_host_page_size,
81: prot1 & PAGE_BITS);
82: if (ret != 0)
83: return ret;
84: host_end -= qemu_host_page_size;
85: }
86:
87: /* handle the pages in the middle */
88: if (host_start < host_end) {
89: ret = mprotect((void *)host_start, host_end - host_start, prot);
90: if (ret != 0)
91: return ret;
92: }
93: page_set_flags(start, start + len, prot | PAGE_VALID);
94: return 0;
95: }
96:
97: /* map an incomplete host page */
98: int mmap_frag(unsigned long host_start,
99: unsigned long start, unsigned long end,
100: int prot, int flags, int fd, unsigned long offset)
101: {
102: unsigned long host_end, ret, addr;
103: int prot1, prot_new;
104:
105: host_end = host_start + qemu_host_page_size;
106:
107: /* get the protection of the target pages outside the mapping */
108: prot1 = 0;
109: for(addr = host_start; addr < host_end; addr++) {
110: if (addr < start || addr >= end)
111: prot1 |= page_get_flags(addr);
112: }
113:
114: if (prot1 == 0) {
115: /* no page was there, so we allocate one */
116: ret = (long)mmap((void *)host_start, qemu_host_page_size, prot,
117: flags | MAP_ANONYMOUS, -1, 0);
118: if (ret == -1)
119: return ret;
120: }
121: prot1 &= PAGE_BITS;
122:
123: prot_new = prot | prot1;
124: if (!(flags & MAP_ANONYMOUS)) {
125: /* msync() won't work here, so we return an error if write is
126: possible while it is a shared mapping */
127: if ((flags & MAP_TYPE) == MAP_SHARED &&
128: (prot & PROT_WRITE))
129: return -EINVAL;
130:
131: /* adjust protection to be able to read */
132: if (!(prot1 & PROT_WRITE))
133: mprotect((void *)host_start, qemu_host_page_size, prot1 | PROT_WRITE);
134:
135: /* read the corresponding file data */
136: pread(fd, (void *)start, end - start, offset);
137:
138: /* put final protection */
139: if (prot_new != (prot1 | PROT_WRITE))
140: mprotect((void *)host_start, qemu_host_page_size, prot_new);
141: } else {
142: /* just update the protection */
143: if (prot_new != prot1) {
144: mprotect((void *)host_start, qemu_host_page_size, prot_new);
145: }
146: }
147: return 0;
148: }
149:
150: /* NOTE: all the constants are the HOST ones */
151: long target_mmap(unsigned long start, unsigned long len, int prot,
152: int flags, int fd, unsigned long offset)
153: {
154: unsigned long ret, end, host_start, host_end, retaddr, host_offset, host_len;
155: #if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__) || \
156: defined(__ia64)
157: static unsigned long last_start = 0x40000000;
158: #endif
159:
160: #ifdef DEBUG_MMAP
161: {
162: printf("mmap: start=0x%lx len=0x%lx prot=%c%c%c flags=",
163: start, len,
164: prot & PROT_READ ? 'r' : '-',
165: prot & PROT_WRITE ? 'w' : '-',
166: prot & PROT_EXEC ? 'x' : '-');
167: if (flags & MAP_FIXED)
168: printf("MAP_FIXED ");
169: if (flags & MAP_ANONYMOUS)
170: printf("MAP_ANON ");
171: switch(flags & MAP_TYPE) {
172: case MAP_PRIVATE:
173: printf("MAP_PRIVATE ");
174: break;
175: case MAP_SHARED:
176: printf("MAP_SHARED ");
177: break;
178: default:
179: printf("[MAP_TYPE=0x%x] ", flags & MAP_TYPE);
180: break;
181: }
182: printf("fd=%d offset=%lx\n", fd, offset);
183: }
184: #endif
185:
186: if (offset & ~TARGET_PAGE_MASK)
187: return -EINVAL;
188:
189: len = TARGET_PAGE_ALIGN(len);
190: if (len == 0)
191: return start;
192: host_start = start & qemu_host_page_mask;
193:
194: if (!(flags & MAP_FIXED)) {
195: #if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__) || \
196: defined(__ia64)
197: /* tell the kenel to search at the same place as i386 */
198: if (host_start == 0) {
199: host_start = last_start;
200: last_start += HOST_PAGE_ALIGN(len);
201: }
202: #endif
203: if (qemu_host_page_size != qemu_real_host_page_size) {
204: /* NOTE: this code is only for debugging with '-p' option */
205: /* reserve a memory area */
206: host_len = HOST_PAGE_ALIGN(len) + qemu_host_page_size - TARGET_PAGE_SIZE;
207: host_start = (long)mmap((void *)host_start, host_len, PROT_NONE,
208: MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
209: if (host_start == -1)
210: return host_start;
211: host_end = host_start + host_len;
212: start = HOST_PAGE_ALIGN(host_start);
213: end = start + HOST_PAGE_ALIGN(len);
214: if (start > host_start)
215: munmap((void *)host_start, start - host_start);
216: if (end < host_end)
217: munmap((void *)end, host_end - end);
218: /* use it as a fixed mapping */
219: flags |= MAP_FIXED;
220: } else {
221: /* if not fixed, no need to do anything */
222: host_offset = offset & qemu_host_page_mask;
223: host_len = len + offset - host_offset;
224: start = (long)mmap((void *)host_start, host_len,
225: prot, flags, fd, host_offset);
226: if (start == -1)
227: return start;
228: /* update start so that it points to the file position at 'offset' */
229: if (!(flags & MAP_ANONYMOUS))
230: start += offset - host_offset;
231: goto the_end1;
232: }
233: }
234:
235: if (start & ~TARGET_PAGE_MASK)
236: return -EINVAL;
237: end = start + len;
238: host_end = HOST_PAGE_ALIGN(end);
239:
240: /* worst case: we cannot map the file because the offset is not
241: aligned, so we read it */
242: if (!(flags & MAP_ANONYMOUS) &&
243: (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) {
244: /* msync() won't work here, so we return an error if write is
245: possible while it is a shared mapping */
246: if ((flags & MAP_TYPE) == MAP_SHARED &&
247: (prot & PROT_WRITE))
248: return -EINVAL;
249: retaddr = target_mmap(start, len, prot | PROT_WRITE,
250: MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
251: -1, 0);
252: if (retaddr == -1)
253: return retaddr;
254: pread(fd, (void *)start, len, offset);
255: if (!(prot & PROT_WRITE)) {
256: ret = target_mprotect(start, len, prot);
257: if (ret != 0)
258: return ret;
259: }
260: goto the_end;
261: }
262:
263: /* handle the start of the mapping */
264: if (start > host_start) {
265: if (host_end == host_start + qemu_host_page_size) {
266: /* one single host page */
267: ret = mmap_frag(host_start, start, end,
268: prot, flags, fd, offset);
269: if (ret == -1)
270: return ret;
271: goto the_end1;
272: }
273: ret = mmap_frag(host_start, start, host_start + qemu_host_page_size,
274: prot, flags, fd, offset);
275: if (ret == -1)
276: return ret;
277: host_start += qemu_host_page_size;
278: }
279: /* handle the end of the mapping */
280: if (end < host_end) {
281: ret = mmap_frag(host_end - qemu_host_page_size,
282: host_end - qemu_host_page_size, host_end,
283: prot, flags, fd,
284: offset + host_end - qemu_host_page_size - start);
285: if (ret == -1)
286: return ret;
287: host_end -= qemu_host_page_size;
288: }
289:
290: /* map the middle (easier) */
291: if (host_start < host_end) {
292: unsigned long offset1;
293: if (flags & MAP_ANONYMOUS)
294: offset1 = 0;
295: else
296: offset1 = offset + host_start - start;
297: ret = (long)mmap((void *)host_start, host_end - host_start,
298: prot, flags, fd, offset1);
299: if (ret == -1)
300: return ret;
301: }
302: the_end1:
303: page_set_flags(start, start + len, prot | PAGE_VALID);
304: the_end:
305: #ifdef DEBUG_MMAP
306: printf("ret=0x%lx\n", (long)start);
307: page_dump(stdout);
308: printf("\n");
309: #endif
310: return start;
311: }
312:
313: int target_munmap(unsigned long start, unsigned long len)
314: {
315: unsigned long end, host_start, host_end, addr;
316: int prot, ret;
317:
318: #ifdef DEBUG_MMAP
319: printf("munmap: start=0x%lx len=0x%lx\n", start, len);
320: #endif
321: if (start & ~TARGET_PAGE_MASK)
322: return -EINVAL;
323: len = TARGET_PAGE_ALIGN(len);
324: if (len == 0)
325: return -EINVAL;
326: end = start + len;
327: host_start = start & qemu_host_page_mask;
328: host_end = HOST_PAGE_ALIGN(end);
329:
330: if (start > host_start) {
331: /* handle host page containing start */
332: prot = 0;
333: for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
334: prot |= page_get_flags(addr);
335: }
336: if (host_end == host_start + qemu_host_page_size) {
337: for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
338: prot |= page_get_flags(addr);
339: }
340: end = host_end;
341: }
342: if (prot != 0)
343: host_start += qemu_host_page_size;
344: }
345: if (end < host_end) {
346: prot = 0;
347: for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
348: prot |= page_get_flags(addr);
349: }
350: if (prot != 0)
351: host_end -= qemu_host_page_size;
352: }
353:
354: /* unmap what we can */
355: if (host_start < host_end) {
356: ret = munmap((void *)host_start, host_end - host_start);
357: if (ret != 0)
358: return ret;
359: }
360:
361: page_set_flags(start, start + len, 0);
362: return 0;
363: }
364:
365: /* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED
366: blocks which have been allocated starting on a host page */
367: long target_mremap(unsigned long old_addr, unsigned long old_size,
368: unsigned long new_size, unsigned long flags,
369: unsigned long new_addr)
370: {
371: int prot;
372:
373: /* XXX: use 5 args syscall */
374: new_addr = (long)mremap((void *)old_addr, old_size, new_size, flags);
375: if (new_addr == -1)
376: return new_addr;
377: prot = page_get_flags(old_addr);
378: page_set_flags(old_addr, old_addr + old_size, 0);
379: page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
380: return new_addr;
381: }
382:
383: int target_msync(unsigned long start, unsigned long len, int flags)
384: {
385: unsigned long end;
386:
387: if (start & ~TARGET_PAGE_MASK)
388: return -EINVAL;
389: len = TARGET_PAGE_ALIGN(len);
390: end = start + len;
391: if (end < start)
392: return -EINVAL;
393: if (end == start)
394: return 0;
395:
396: start &= qemu_host_page_mask;
397: return msync((void *)start, end - start, flags);
398: }
399:
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