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(abi_ulong start, abi_ulong len, int prot)
35 abi_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 prot &= PROT_READ | PROT_WRITE | PROT_EXEC;
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 */
61 for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
62 prot1 |= page_get_flags(addr);
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);
70 ret = mprotect(g2h(host_start), qemu_host_page_size, prot1 & PAGE_BITS);
73 host_start += qemu_host_page_size;
77 for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
78 prot1 |= page_get_flags(addr);
80 ret = mprotect(g2h(host_end - qemu_host_page_size), qemu_host_page_size,
84 host_end -= qemu_host_page_size;
87 /* handle the pages in the middle */
88 if (host_start < host_end) {
89 ret = mprotect(g2h(host_start), host_end - host_start, prot);
93 page_set_flags(start, start + len, prot | PAGE_VALID);
97 /* map an incomplete host page */
98 static int mmap_frag(abi_ulong real_start,
99 abi_ulong start, abi_ulong end,
100 int prot, int flags, int fd, abi_ulong offset)
102 abi_ulong real_end, addr;
106 real_end = real_start + qemu_host_page_size;
107 host_start = g2h(real_start);
109 /* get the protection of the target pages outside the mapping */
111 for(addr = real_start; addr < real_end; addr++) {
112 if (addr < start || addr >= end)
113 prot1 |= page_get_flags(addr);
117 /* no page was there, so we allocate one */
118 void *p = mmap(host_start, qemu_host_page_size, prot,
119 flags | MAP_ANONYMOUS, -1, 0);
126 prot_new = prot | prot1;
127 if (!(flags & MAP_ANONYMOUS)) {
128 /* msync() won't work here, so we return an error if write is
129 possible while it is a shared mapping */
130 if ((flags & MAP_TYPE) == MAP_SHARED &&
134 /* adjust protection to be able to read */
135 if (!(prot1 & PROT_WRITE))
136 mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE);
138 /* read the corresponding file data */
139 pread(fd, g2h(start), end - start, offset);
141 /* put final protection */
142 if (prot_new != (prot1 | PROT_WRITE))
143 mprotect(host_start, qemu_host_page_size, prot_new);
145 /* just update the protection */
146 if (prot_new != prot1) {
147 mprotect(host_start, qemu_host_page_size, prot_new);
153 #if defined(__CYGWIN__)
154 /* Cygwin doesn't have a whole lot of address space. */
155 static abi_ulong mmap_next_start = 0x18000000;
157 static abi_ulong mmap_next_start = 0x40000000;
160 /* find a free memory area of size 'size'. The search starts at
161 'start'. If 'start' == 0, then a default start address is used.
164 /* page_init() marks pages used by the host as reserved to be sure not
166 static abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
168 abi_ulong addr, addr1, addr_start;
171 size = HOST_PAGE_ALIGN(size);
172 start = start & qemu_host_page_mask;
175 addr = mmap_next_start;
179 for(addr1 = addr; addr1 < (addr + size); addr1 += TARGET_PAGE_SIZE) {
180 prot |= page_get_flags(addr1);
184 addr += qemu_host_page_size;
185 /* we found nothing */
186 if (addr == addr_start)
187 return (abi_ulong)-1;
190 mmap_next_start = addr + size;
194 /* NOTE: all the constants are the HOST ones */
195 abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
196 int flags, int fd, abi_ulong offset)
198 abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len;
199 unsigned long host_start;
203 printf("mmap: start=0x" TARGET_FMT_lx
204 " len=0x" TARGET_FMT_lx " prot=%c%c%c flags=",
206 prot & PROT_READ ? 'r' : '-',
207 prot & PROT_WRITE ? 'w' : '-',
208 prot & PROT_EXEC ? 'x' : '-');
209 if (flags & MAP_FIXED)
210 printf("MAP_FIXED ");
211 if (flags & MAP_ANONYMOUS)
213 switch(flags & MAP_TYPE) {
215 printf("MAP_PRIVATE ");
218 printf("MAP_SHARED ");
221 printf("[MAP_TYPE=0x%x] ", flags & MAP_TYPE);
224 printf("fd=%d offset=" TARGET_FMT_lx "\n", fd, offset);
228 if (offset & ~TARGET_PAGE_MASK) {
233 len = TARGET_PAGE_ALIGN(len);
236 real_start = start & qemu_host_page_mask;
238 if (!(flags & MAP_FIXED)) {
239 abi_ulong mmap_start;
241 host_offset = offset & qemu_host_page_mask;
242 host_len = len + offset - host_offset;
243 host_len = HOST_PAGE_ALIGN(host_len);
244 mmap_start = mmap_find_vma(real_start, host_len);
245 if (mmap_start == (abi_ulong)-1) {
249 /* Note: we prefer to control the mapping address. It is
250 especially important if qemu_host_page_size >
251 qemu_real_host_page_size */
252 p = mmap(g2h(mmap_start),
253 host_len, prot, flags | MAP_FIXED, fd, host_offset);
256 /* update start so that it points to the file position at 'offset' */
257 host_start = (unsigned long)p;
258 if (!(flags & MAP_ANONYMOUS))
259 host_start += offset - host_offset;
260 start = h2g(host_start);
262 if (start & ~TARGET_PAGE_MASK) {
267 real_end = HOST_PAGE_ALIGN(end);
269 /* worst case: we cannot map the file because the offset is not
270 aligned, so we read it */
271 if (!(flags & MAP_ANONYMOUS) &&
272 (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) {
273 /* msync() won't work here, so we return an error if write is
274 possible while it is a shared mapping */
275 if ((flags & MAP_TYPE) == MAP_SHARED &&
276 (prot & PROT_WRITE)) {
280 retaddr = target_mmap(start, len, prot | PROT_WRITE,
281 MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
285 pread(fd, g2h(start), len, offset);
286 if (!(prot & PROT_WRITE)) {
287 ret = target_mprotect(start, len, prot);
294 /* handle the start of the mapping */
295 if (start > real_start) {
296 if (real_end == real_start + qemu_host_page_size) {
297 /* one single host page */
298 ret = mmap_frag(real_start, start, end,
299 prot, flags, fd, offset);
304 ret = mmap_frag(real_start, start, real_start + qemu_host_page_size,
305 prot, flags, fd, offset);
308 real_start += qemu_host_page_size;
310 /* handle the end of the mapping */
311 if (end < real_end) {
312 ret = mmap_frag(real_end - qemu_host_page_size,
313 real_end - qemu_host_page_size, real_end,
315 offset + real_end - qemu_host_page_size - start);
318 real_end -= qemu_host_page_size;
321 /* map the middle (easier) */
322 if (real_start < real_end) {
324 unsigned long offset1;
325 if (flags & MAP_ANONYMOUS)
328 offset1 = offset + real_start - start;
329 p = mmap(g2h(real_start), real_end - real_start,
330 prot, flags, fd, offset1);
336 page_set_flags(start, start + len, prot | PAGE_VALID);
339 printf("ret=0x" TARGET_FMT_lx "\n", start);
346 int target_munmap(abi_ulong start, abi_ulong len)
348 abi_ulong end, real_start, real_end, addr;
352 printf("munmap: start=0x%lx len=0x%lx\n", start, len);
354 if (start & ~TARGET_PAGE_MASK)
356 len = TARGET_PAGE_ALIGN(len);
360 real_start = start & qemu_host_page_mask;
361 real_end = HOST_PAGE_ALIGN(end);
363 if (start > real_start) {
364 /* handle host page containing start */
366 for(addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) {
367 prot |= page_get_flags(addr);
369 if (real_end == real_start + qemu_host_page_size) {
370 for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
371 prot |= page_get_flags(addr);
376 real_start += qemu_host_page_size;
378 if (end < real_end) {
380 for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
381 prot |= page_get_flags(addr);
384 real_end -= qemu_host_page_size;
387 /* unmap what we can */
388 if (real_start < real_end) {
389 ret = munmap(g2h(real_start), real_end - real_start);
394 page_set_flags(start, start + len, 0);
398 /* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED
399 blocks which have been allocated starting on a host page */
400 abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
401 abi_ulong new_size, unsigned long flags,
405 unsigned long host_addr;
407 /* XXX: use 5 args syscall */
408 host_addr = (long)mremap(g2h(old_addr), old_size, new_size, flags);
411 new_addr = h2g(host_addr);
412 prot = page_get_flags(old_addr);
413 page_set_flags(old_addr, old_addr + old_size, 0);
414 page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
418 int target_msync(abi_ulong start, abi_ulong len, int flags)
422 if (start & ~TARGET_PAGE_MASK)
424 len = TARGET_PAGE_ALIGN(len);
431 start &= qemu_host_page_mask;
432 return msync(g2h(start), end - start, flags);