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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
1.1.1.3 ! root 18: * Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
! 19: * MA 02110-1301, USA.
1.1 root 20: */
21: #include <stdlib.h>
22: #include <stdio.h>
23: #include <stdarg.h>
24: #include <string.h>
25: #include <unistd.h>
26: #include <errno.h>
27: #include <sys/mman.h>
28:
29: #include "qemu.h"
30:
31: //#define DEBUG_MMAP
32:
33: /* NOTE: all the constants are the HOST ones */
34: int target_mprotect(unsigned long start, unsigned long len, int prot)
35: {
36: unsigned long end, host_start, host_end, addr;
37: int prot1, ret;
38:
39: #ifdef DEBUG_MMAP
40: printf("mprotect: start=0x%lx len=0x%lx prot=%c%c%c\n", start, len,
41: prot & PROT_READ ? 'r' : '-',
42: prot & PROT_WRITE ? 'w' : '-',
43: prot & PROT_EXEC ? 'x' : '-');
44: #endif
45:
46: if ((start & ~TARGET_PAGE_MASK) != 0)
47: return -EINVAL;
48: len = TARGET_PAGE_ALIGN(len);
49: end = start + len;
50: if (end < start)
51: return -EINVAL;
52: if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC))
53: return -EINVAL;
54: if (len == 0)
55: return 0;
56:
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 */
61: prot1 = prot;
62: for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
63: prot1 |= page_get_flags(addr);
64: }
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);
68: }
69: end = host_end;
70: }
71: ret = mprotect((void *)host_start, qemu_host_page_size, prot1 & PAGE_BITS);
72: if (ret != 0)
73: return ret;
74: host_start += qemu_host_page_size;
75: }
76: if (end < host_end) {
77: prot1 = prot;
78: for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
79: prot1 |= page_get_flags(addr);
80: }
81: ret = mprotect((void *)(host_end - qemu_host_page_size), qemu_host_page_size,
82: prot1 & PAGE_BITS);
83: if (ret != 0)
84: return ret;
85: host_end -= qemu_host_page_size;
86: }
87:
88: /* handle the pages in the middle */
89: if (host_start < host_end) {
90: ret = mprotect((void *)host_start, host_end - host_start, prot);
91: if (ret != 0)
92: return ret;
93: }
94: page_set_flags(start, start + len, prot | PAGE_VALID);
95: return 0;
96: }
97:
98: /* map an incomplete host page */
99: int mmap_frag(unsigned long host_start,
100: unsigned long start, unsigned long end,
101: int prot, int flags, int fd, unsigned long offset)
102: {
103: unsigned long host_end, ret, addr;
104: int prot1, prot_new;
105:
106: host_end = host_start + qemu_host_page_size;
107:
108: /* get the protection of the target pages outside the mapping */
109: prot1 = 0;
110: for(addr = host_start; addr < host_end; addr++) {
111: if (addr < start || addr >= end)
112: prot1 |= page_get_flags(addr);
113: }
114:
115: if (prot1 == 0) {
116: /* no page was there, so we allocate one */
117: ret = (long)mmap((void *)host_start, qemu_host_page_size, prot,
118: flags | MAP_ANONYMOUS, -1, 0);
119: if (ret == -1)
120: return ret;
121: }
122: prot1 &= PAGE_BITS;
123:
124: prot_new = prot | prot1;
125: if (!(flags & MAP_ANONYMOUS)) {
126: /* msync() won't work here, so we return an error if write is
127: possible while it is a shared mapping */
128: #ifndef __APPLE__
129: if ((flags & MAP_TYPE) == MAP_SHARED &&
130: #else
131: if ((flags & MAP_SHARED) &&
132: #endif
133: (prot & PROT_WRITE))
134: return -EINVAL;
135:
136: /* adjust protection to be able to read */
137: if (!(prot1 & PROT_WRITE))
138: mprotect((void *)host_start, qemu_host_page_size, prot1 | PROT_WRITE);
139:
140: /* read the corresponding file data */
141: pread(fd, (void *)start, end - start, offset);
142:
143: /* put final protection */
144: if (prot_new != (prot1 | PROT_WRITE))
145: mprotect((void *)host_start, qemu_host_page_size, prot_new);
146: } else {
147: /* just update the protection */
148: if (prot_new != prot1) {
149: mprotect((void *)host_start, qemu_host_page_size, prot_new);
150: }
151: }
152: return 0;
153: }
154:
155: /* NOTE: all the constants are the HOST ones */
156: long target_mmap(unsigned long start, unsigned long len, int prot,
157: int flags, int fd, unsigned long offset)
158: {
159: unsigned long ret, end, host_start, host_end, retaddr, host_offset, host_len;
160: #if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__)
161: static unsigned long last_start = 0x40000000;
162: #endif
163:
164: #ifdef DEBUG_MMAP
165: {
166: printf("mmap: start=0x%lx len=0x%lx prot=%c%c%c flags=",
167: start, len,
168: prot & PROT_READ ? 'r' : '-',
169: prot & PROT_WRITE ? 'w' : '-',
170: prot & PROT_EXEC ? 'x' : '-');
171: if (flags & MAP_FIXED)
172: printf("MAP_FIXED ");
173: if (flags & MAP_ANONYMOUS)
174: printf("MAP_ANON ");
175: #ifndef MAP_TYPE
176: # define MAP_TYPE 0x3
177: #endif
178: switch(flags & MAP_TYPE) {
179: case MAP_PRIVATE:
180: printf("MAP_PRIVATE ");
181: break;
182: case MAP_SHARED:
183: printf("MAP_SHARED ");
184: break;
185: default:
186: printf("[MAP_TYPE=0x%x] ", flags & MAP_TYPE);
187: break;
188: }
189: printf("fd=%d offset=%lx\n", fd, offset);
190: }
191: #endif
192:
193: if (offset & ~TARGET_PAGE_MASK)
194: return -EINVAL;
195:
196: len = TARGET_PAGE_ALIGN(len);
197: if (len == 0)
198: return start;
199: host_start = start & qemu_host_page_mask;
200:
201: if (!(flags & MAP_FIXED)) {
202: #if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__)
1.1.1.2 root 203: /* tell the kernel to search at the same place as i386 */
1.1 root 204: if (host_start == 0) {
205: host_start = last_start;
206: last_start += HOST_PAGE_ALIGN(len);
207: }
208: #endif
209: if (qemu_host_page_size != qemu_real_host_page_size) {
210: /* NOTE: this code is only for debugging with '-p' option */
211: /* reserve a memory area */
212: host_len = HOST_PAGE_ALIGN(len) + qemu_host_page_size - TARGET_PAGE_SIZE;
213: host_start = (long)mmap((void *)host_start, host_len, PROT_NONE,
214: MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
215: if (host_start == -1)
216: return host_start;
217: host_end = host_start + host_len;
218: start = HOST_PAGE_ALIGN(host_start);
219: end = start + HOST_PAGE_ALIGN(len);
220: if (start > host_start)
221: munmap((void *)host_start, start - host_start);
222: if (end < host_end)
223: munmap((void *)end, host_end - end);
224: /* use it as a fixed mapping */
225: flags |= MAP_FIXED;
226: } else {
227: /* if not fixed, no need to do anything */
228: host_offset = offset & qemu_host_page_mask;
229: host_len = len + offset - host_offset;
230: start = (long)mmap((void *)host_start, host_len,
231: prot, flags, fd, host_offset);
232: if (start == -1)
233: return start;
234: /* update start so that it points to the file position at 'offset' */
235: if (!(flags & MAP_ANONYMOUS))
236: start += offset - host_offset;
237: goto the_end1;
238: }
239: }
240:
241: if (start & ~TARGET_PAGE_MASK)
242: return -EINVAL;
243: end = start + len;
244: host_end = HOST_PAGE_ALIGN(end);
245:
246: /* worst case: we cannot map the file because the offset is not
247: aligned, so we read it */
248: if (!(flags & MAP_ANONYMOUS) &&
249: (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) {
250: /* msync() won't work here, so we return an error if write is
251: possible while it is a shared mapping */
252: #ifndef __APPLE__
253: if ((flags & MAP_TYPE) == MAP_SHARED &&
254: #else
255: if ((flags & MAP_SHARED) &&
256: #endif
257: (prot & PROT_WRITE))
258: return -EINVAL;
259: retaddr = target_mmap(start, len, prot | PROT_WRITE,
260: MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
261: -1, 0);
262: if (retaddr == -1)
263: return retaddr;
264: pread(fd, (void *)start, len, offset);
265: if (!(prot & PROT_WRITE)) {
266: ret = target_mprotect(start, len, prot);
267: if (ret != 0)
268: return ret;
269: }
270: goto the_end;
271: }
272:
273: /* handle the start of the mapping */
274: if (start > host_start) {
275: if (host_end == host_start + qemu_host_page_size) {
276: /* one single host page */
277: ret = mmap_frag(host_start, start, end,
278: prot, flags, fd, offset);
279: if (ret == -1)
280: return ret;
281: goto the_end1;
282: }
283: ret = mmap_frag(host_start, start, host_start + qemu_host_page_size,
284: prot, flags, fd, offset);
285: if (ret == -1)
286: return ret;
287: host_start += qemu_host_page_size;
288: }
289: /* handle the end of the mapping */
290: if (end < host_end) {
291: ret = mmap_frag(host_end - qemu_host_page_size,
292: host_end - qemu_host_page_size, host_end,
293: prot, flags, fd,
294: offset + host_end - qemu_host_page_size - start);
295: if (ret == -1)
296: return ret;
297: host_end -= qemu_host_page_size;
298: }
299:
300: /* map the middle (easier) */
301: if (host_start < host_end) {
302: unsigned long offset1;
303: if (flags & MAP_ANONYMOUS)
304: offset1 = 0;
305: else
306: offset1 = offset + host_start - start;
307: ret = (long)mmap((void *)host_start, host_end - host_start,
308: prot, flags, fd, offset1);
309: if (ret == -1)
310: return ret;
311: }
312: the_end1:
313: page_set_flags(start, start + len, prot | PAGE_VALID);
314: the_end:
315: #ifdef DEBUG_MMAP
316: printf("target_mmap: ret=0x%lx\n", (long)start);
317: page_dump(stdout);
318: printf("\n");
319: #endif
320: return start;
321: }
322:
323: int target_munmap(unsigned long start, unsigned long len)
324: {
325: unsigned long end, host_start, host_end, addr;
326: int prot, ret;
327:
328: #ifdef DEBUG_MMAP
329: printf("munmap: start=0x%lx len=0x%lx\n", start, len);
330: #endif
331: if (start & ~TARGET_PAGE_MASK)
332: return -EINVAL;
333: len = TARGET_PAGE_ALIGN(len);
334: if (len == 0)
335: return -EINVAL;
336: end = start + len;
337: host_start = start & qemu_host_page_mask;
338: host_end = HOST_PAGE_ALIGN(end);
339:
340: if (start > host_start) {
341: /* handle host page containing start */
342: prot = 0;
343: for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
344: prot |= page_get_flags(addr);
345: }
346: if (host_end == host_start + qemu_host_page_size) {
347: for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
348: prot |= page_get_flags(addr);
349: }
350: end = host_end;
351: }
352: if (prot != 0)
353: host_start += qemu_host_page_size;
354: }
355: if (end < host_end) {
356: prot = 0;
357: for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
358: prot |= page_get_flags(addr);
359: }
360: if (prot != 0)
361: host_end -= qemu_host_page_size;
362: }
363:
364: /* unmap what we can */
365: if (host_start < host_end) {
366: ret = munmap((void *)host_start, host_end - host_start);
367: if (ret != 0)
368: return ret;
369: }
370:
371: page_set_flags(start, start + len, 0);
372: return 0;
373: }
374:
375: /* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED
376: blocks which have been allocated starting on a host page */
377: long target_mremap(unsigned long old_addr, unsigned long old_size,
378: unsigned long new_size, unsigned long flags,
379: unsigned long new_addr)
380: {
381: #ifndef __APPLE__
382: /* XXX: use 5 args syscall */
383: new_addr = (long)mremap((void *)old_addr, old_size, new_size, flags);
384: if (new_addr == -1)
385: return new_addr;
386: prot = page_get_flags(old_addr);
387: page_set_flags(old_addr, old_addr + old_size, 0);
388: page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
389: return new_addr;
390: #else
391: qerror("target_mremap: unsupported\n");
392: #endif
393:
394: }
395:
396: int target_msync(unsigned long start, unsigned long len, int flags)
397: {
398: unsigned long end;
399:
400: if (start & ~TARGET_PAGE_MASK)
401: return -EINVAL;
402: len = TARGET_PAGE_ALIGN(len);
403: end = start + len;
404: if (end < start)
405: return -EINVAL;
406: if (end == start)
407: return 0;
408:
409: start &= qemu_host_page_mask;
410: return msync((void *)start, end - start, flags);
411: }
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