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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
1.1.1.4 root 17: * along with this program; if not, see <http://www.gnu.org/licenses/>.
1.1 root 18: */
19: #include <stdlib.h>
20: #include <stdio.h>
21: #include <stdarg.h>
22: #include <string.h>
23: #include <unistd.h>
24: #include <errno.h>
25: #include <sys/mman.h>
26:
27: #include "qemu.h"
28:
29: //#define DEBUG_MMAP
30:
31: /* NOTE: all the constants are the HOST ones */
32: int target_mprotect(unsigned long start, unsigned long len, int prot)
33: {
34: unsigned long end, host_start, host_end, addr;
35: int prot1, ret;
36:
37: #ifdef DEBUG_MMAP
38: printf("mprotect: start=0x%lx len=0x%lx prot=%c%c%c\n", start, len,
39: prot & PROT_READ ? 'r' : '-',
40: prot & PROT_WRITE ? 'w' : '-',
41: prot & PROT_EXEC ? 'x' : '-');
42: #endif
43:
44: if ((start & ~TARGET_PAGE_MASK) != 0)
45: return -EINVAL;
46: len = TARGET_PAGE_ALIGN(len);
47: end = start + len;
48: if (end < start)
49: return -EINVAL;
50: if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC))
51: return -EINVAL;
52: if (len == 0)
53: return 0;
54:
55: host_start = start & qemu_host_page_mask;
56: host_end = HOST_PAGE_ALIGN(end);
57: if (start > host_start) {
58: /* handle host page containing start */
59: prot1 = prot;
60: for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
61: prot1 |= page_get_flags(addr);
62: }
63: if (host_end == host_start + qemu_host_page_size) {
64: for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
65: prot1 |= page_get_flags(addr);
66: }
67: end = host_end;
68: }
69: ret = mprotect((void *)host_start, qemu_host_page_size, prot1 & PAGE_BITS);
70: if (ret != 0)
71: return ret;
72: host_start += qemu_host_page_size;
73: }
74: if (end < host_end) {
75: prot1 = prot;
76: for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
77: prot1 |= page_get_flags(addr);
78: }
79: ret = mprotect((void *)(host_end - qemu_host_page_size), qemu_host_page_size,
80: prot1 & PAGE_BITS);
81: if (ret != 0)
82: return ret;
83: host_end -= qemu_host_page_size;
84: }
85:
86: /* handle the pages in the middle */
87: if (host_start < host_end) {
88: ret = mprotect((void *)host_start, host_end - host_start, prot);
89: if (ret != 0)
90: return ret;
91: }
92: page_set_flags(start, start + len, prot | PAGE_VALID);
93: return 0;
94: }
95:
96: /* map an incomplete host page */
97: int mmap_frag(unsigned long host_start,
98: unsigned long start, unsigned long end,
99: int prot, int flags, int fd, unsigned long offset)
100: {
101: unsigned long host_end, ret, addr;
102: int prot1, prot_new;
103:
104: host_end = host_start + qemu_host_page_size;
105:
106: /* get the protection of the target pages outside the mapping */
107: prot1 = 0;
108: for(addr = host_start; addr < host_end; addr++) {
109: if (addr < start || addr >= end)
110: prot1 |= page_get_flags(addr);
111: }
112:
113: if (prot1 == 0) {
114: /* no page was there, so we allocate one */
115: ret = (long)mmap((void *)host_start, qemu_host_page_size, prot,
116: flags | MAP_ANONYMOUS, -1, 0);
117: if (ret == -1)
118: return ret;
119: }
120: prot1 &= PAGE_BITS;
121:
122: prot_new = prot | prot1;
123: if (!(flags & MAP_ANONYMOUS)) {
124: /* msync() won't work here, so we return an error if write is
125: possible while it is a shared mapping */
126: #ifndef __APPLE__
127: if ((flags & MAP_TYPE) == MAP_SHARED &&
128: #else
129: if ((flags & MAP_SHARED) &&
130: #endif
131: (prot & PROT_WRITE))
1.1.1.5 ! root 132: return -1;
1.1 root 133:
134: /* adjust protection to be able to read */
135: if (!(prot1 & PROT_WRITE))
136: mprotect((void *)host_start, qemu_host_page_size, prot1 | PROT_WRITE);
137:
138: /* read the corresponding file data */
139: pread(fd, (void *)start, end - start, offset);
140:
141: /* put final protection */
142: if (prot_new != (prot1 | PROT_WRITE))
143: mprotect((void *)host_start, qemu_host_page_size, prot_new);
144: } else {
145: /* just update the protection */
146: if (prot_new != prot1) {
147: mprotect((void *)host_start, qemu_host_page_size, prot_new);
148: }
149: }
150: return 0;
151: }
152:
153: /* NOTE: all the constants are the HOST ones */
154: long target_mmap(unsigned long start, unsigned long len, int prot,
155: int flags, int fd, unsigned long offset)
156: {
157: unsigned long ret, end, host_start, host_end, retaddr, host_offset, host_len;
158: #if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__)
159: static unsigned long last_start = 0x40000000;
160: #endif
161:
162: #ifdef DEBUG_MMAP
163: {
164: printf("mmap: start=0x%lx len=0x%lx prot=%c%c%c flags=",
165: start, len,
166: prot & PROT_READ ? 'r' : '-',
167: prot & PROT_WRITE ? 'w' : '-',
168: prot & PROT_EXEC ? 'x' : '-');
169: if (flags & MAP_FIXED)
170: printf("MAP_FIXED ");
171: if (flags & MAP_ANONYMOUS)
172: printf("MAP_ANON ");
173: #ifndef MAP_TYPE
174: # define MAP_TYPE 0x3
175: #endif
176: switch(flags & MAP_TYPE) {
177: case MAP_PRIVATE:
178: printf("MAP_PRIVATE ");
179: break;
180: case MAP_SHARED:
181: printf("MAP_SHARED ");
182: break;
183: default:
184: printf("[MAP_TYPE=0x%x] ", flags & MAP_TYPE);
185: break;
186: }
187: printf("fd=%d offset=%lx\n", fd, offset);
188: }
189: #endif
190:
191: if (offset & ~TARGET_PAGE_MASK)
192: return -EINVAL;
193:
194: len = TARGET_PAGE_ALIGN(len);
195: if (len == 0)
196: return start;
197: host_start = start & qemu_host_page_mask;
198:
199: if (!(flags & MAP_FIXED)) {
200: #if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__)
1.1.1.2 root 201: /* tell the kernel to search at the same place as i386 */
1.1 root 202: if (host_start == 0) {
203: host_start = last_start;
204: last_start += HOST_PAGE_ALIGN(len);
205: }
206: #endif
207: if (qemu_host_page_size != qemu_real_host_page_size) {
208: /* NOTE: this code is only for debugging with '-p' option */
209: /* reserve a memory area */
210: host_len = HOST_PAGE_ALIGN(len) + qemu_host_page_size - TARGET_PAGE_SIZE;
211: host_start = (long)mmap((void *)host_start, host_len, PROT_NONE,
212: MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
213: if (host_start == -1)
214: return host_start;
215: host_end = host_start + host_len;
216: start = HOST_PAGE_ALIGN(host_start);
217: end = start + HOST_PAGE_ALIGN(len);
218: if (start > host_start)
219: munmap((void *)host_start, start - host_start);
220: if (end < host_end)
221: munmap((void *)end, host_end - end);
222: /* use it as a fixed mapping */
223: flags |= MAP_FIXED;
224: } else {
225: /* if not fixed, no need to do anything */
226: host_offset = offset & qemu_host_page_mask;
227: host_len = len + offset - host_offset;
228: start = (long)mmap((void *)host_start, host_len,
229: prot, flags, fd, host_offset);
230: if (start == -1)
231: return start;
232: /* update start so that it points to the file position at 'offset' */
233: if (!(flags & MAP_ANONYMOUS))
234: start += offset - host_offset;
235: goto the_end1;
236: }
237: }
238:
239: if (start & ~TARGET_PAGE_MASK)
240: return -EINVAL;
241: end = start + len;
242: host_end = HOST_PAGE_ALIGN(end);
243:
244: /* worst case: we cannot map the file because the offset is not
245: aligned, so we read it */
246: if (!(flags & MAP_ANONYMOUS) &&
247: (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) {
248: /* msync() won't work here, so we return an error if write is
249: possible while it is a shared mapping */
250: #ifndef __APPLE__
251: if ((flags & MAP_TYPE) == MAP_SHARED &&
252: #else
253: if ((flags & MAP_SHARED) &&
254: #endif
255: (prot & PROT_WRITE))
256: return -EINVAL;
257: retaddr = target_mmap(start, len, prot | PROT_WRITE,
258: MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
259: -1, 0);
260: if (retaddr == -1)
261: return retaddr;
262: pread(fd, (void *)start, len, offset);
263: if (!(prot & PROT_WRITE)) {
264: ret = target_mprotect(start, len, prot);
265: if (ret != 0)
266: return ret;
267: }
268: goto the_end;
269: }
270:
271: /* handle the start of the mapping */
272: if (start > host_start) {
273: if (host_end == host_start + qemu_host_page_size) {
274: /* one single host page */
275: ret = mmap_frag(host_start, start, end,
276: prot, flags, fd, offset);
277: if (ret == -1)
278: return ret;
279: goto the_end1;
280: }
281: ret = mmap_frag(host_start, start, host_start + qemu_host_page_size,
282: prot, flags, fd, offset);
283: if (ret == -1)
284: return ret;
285: host_start += qemu_host_page_size;
286: }
287: /* handle the end of the mapping */
288: if (end < host_end) {
289: ret = mmap_frag(host_end - qemu_host_page_size,
290: host_end - qemu_host_page_size, host_end,
291: prot, flags, fd,
292: offset + host_end - qemu_host_page_size - start);
293: if (ret == -1)
294: return ret;
295: host_end -= qemu_host_page_size;
296: }
297:
298: /* map the middle (easier) */
299: if (host_start < host_end) {
300: unsigned long offset1;
301: if (flags & MAP_ANONYMOUS)
302: offset1 = 0;
303: else
304: offset1 = offset + host_start - start;
305: ret = (long)mmap((void *)host_start, host_end - host_start,
306: prot, flags, fd, offset1);
307: if (ret == -1)
308: return ret;
309: }
310: the_end1:
311: page_set_flags(start, start + len, prot | PAGE_VALID);
312: the_end:
313: #ifdef DEBUG_MMAP
314: printf("target_mmap: ret=0x%lx\n", (long)start);
315: page_dump(stdout);
316: printf("\n");
317: #endif
318: return start;
319: }
320:
321: int target_munmap(unsigned long start, unsigned long len)
322: {
323: unsigned long end, host_start, host_end, addr;
324: int prot, ret;
325:
326: #ifdef DEBUG_MMAP
327: printf("munmap: start=0x%lx len=0x%lx\n", start, len);
328: #endif
329: if (start & ~TARGET_PAGE_MASK)
330: return -EINVAL;
331: len = TARGET_PAGE_ALIGN(len);
332: if (len == 0)
333: return -EINVAL;
334: end = start + len;
335: host_start = start & qemu_host_page_mask;
336: host_end = HOST_PAGE_ALIGN(end);
337:
338: if (start > host_start) {
339: /* handle host page containing start */
340: prot = 0;
341: for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
342: prot |= page_get_flags(addr);
343: }
344: if (host_end == host_start + qemu_host_page_size) {
345: for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
346: prot |= page_get_flags(addr);
347: }
348: end = host_end;
349: }
350: if (prot != 0)
351: host_start += qemu_host_page_size;
352: }
353: if (end < host_end) {
354: prot = 0;
355: for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
356: prot |= page_get_flags(addr);
357: }
358: if (prot != 0)
359: host_end -= qemu_host_page_size;
360: }
361:
362: /* unmap what we can */
363: if (host_start < host_end) {
364: ret = munmap((void *)host_start, host_end - host_start);
365: if (ret != 0)
366: return ret;
367: }
368:
369: page_set_flags(start, start + len, 0);
370: return 0;
371: }
372:
373: /* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED
374: blocks which have been allocated starting on a host page */
375: long target_mremap(unsigned long old_addr, unsigned long old_size,
376: unsigned long new_size, unsigned long flags,
377: unsigned long new_addr)
378: {
379: #ifndef __APPLE__
380: /* XXX: use 5 args syscall */
381: new_addr = (long)mremap((void *)old_addr, old_size, new_size, flags);
382: if (new_addr == -1)
383: return new_addr;
384: prot = page_get_flags(old_addr);
385: page_set_flags(old_addr, old_addr + old_size, 0);
386: page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
387: return new_addr;
388: #else
389: qerror("target_mremap: unsupported\n");
390: #endif
391:
392: }
393:
394: int target_msync(unsigned long start, unsigned long len, int flags)
395: {
396: unsigned long end;
397:
398: if (start & ~TARGET_PAGE_MASK)
399: return -EINVAL;
400: len = TARGET_PAGE_ALIGN(len);
401: end = start + len;
402: if (end < start)
403: return -EINVAL;
404: if (end == start)
405: return 0;
406:
407: start &= qemu_host_page_mask;
408: return msync((void *)start, end - start, flags);
409: }
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