darwin-user/mmap.c

   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 #ifndef __APPLE__
 128         if ((flags & MAP_TYPE) == MAP_SHARED &&
 129 #else
 130         if ((flags &  MAP_SHARED) &&
 131 #endif
 132             (prot & PROT_WRITE))
 133             return -EINVAL;
 134
 135         /* adjust protection to be able to read */
 136         if (!(prot1 & PROT_WRITE))
 137             mprotect((void *)host_start, qemu_host_page_size, prot1 | PROT_WRITE);
 138
 139         /* read the corresponding file data */
 140         pread(fd, (void *)start, end - start, offset);
 141
 142         /* put final protection */
 143         if (prot_new != (prot1 | PROT_WRITE))
 144             mprotect((void *)host_start, qemu_host_page_size, prot_new);
 145     } else {
 146         /* just update the protection */
 147         if (prot_new != prot1) {
 148             mprotect((void *)host_start, qemu_host_page_size, prot_new);
 149         }
 150     }
 151     return 0;
 152 }
 153
 154 /* NOTE: all the constants are the HOST ones */
 155 long target_mmap(unsigned long start, unsigned long len, int prot,
 156                  int flags, int fd, unsigned long offset)
 157 {
 158     unsigned long ret, end, host_start, host_end, retaddr, host_offset, host_len;
 159 #if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__)
 160     static unsigned long last_start = 0x40000000;
 161 #endif
 162
 163 #ifdef DEBUG_MMAP
 164     {
 165         printf("mmap: start=0x%lx len=0x%lx prot=%c%c%c flags=",
 166                start, len,
 167                prot & PROT_READ ? 'r' : '-',
 168                prot & PROT_WRITE ? 'w' : '-',
 169                prot & PROT_EXEC ? 'x' : '-');
 170         if (flags & MAP_FIXED)
 171             printf("MAP_FIXED ");
 172         if (flags & MAP_ANONYMOUS)
 173             printf("MAP_ANON ");
 174 #ifndef MAP_TYPE
 175 # define MAP_TYPE 0x3
 176 #endif
 177         switch(flags & MAP_TYPE) {
 178         case MAP_PRIVATE:
 179             printf("MAP_PRIVATE ");
 180             break;
 181         case MAP_SHARED:
 182             printf("MAP_SHARED ");
 183             break;
 184         default:
 185             printf("[MAP_TYPE=0x%x] ", flags & MAP_TYPE);
 186             break;
 187         }
 188         printf("fd=%d offset=%lx\n", fd, offset);
 189     }
 190 #endif
 191
 192     if (offset & ~TARGET_PAGE_MASK)
 193         return -EINVAL;
 194
 195     len = TARGET_PAGE_ALIGN(len);
 196     if (len == 0)
 197         return start;
 198     host_start = start & qemu_host_page_mask;
 199
 200     if (!(flags & MAP_FIXED)) {
 201 #if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__)
 202         /* tell the kernel to search at the same place as i386 */
 203         if (host_start == 0) {
 204             host_start = last_start;
 205             last_start += HOST_PAGE_ALIGN(len);
 206         }
 207 #endif
 208         if (qemu_host_page_size != qemu_real_host_page_size) {
 209             /* NOTE: this code is only for debugging with '-p' option */
 210             /* reserve a memory area */
 211             host_len = HOST_PAGE_ALIGN(len) + qemu_host_page_size - TARGET_PAGE_SIZE;
 212             host_start = (long)mmap((void *)host_start, host_len, PROT_NONE,
 213                                     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 214             if (host_start == -1)
 215                 return host_start;
 216             host_end = host_start + host_len;
 217             start = HOST_PAGE_ALIGN(host_start);
 218             end = start + HOST_PAGE_ALIGN(len);
 219             if (start > host_start)
 220                 munmap((void *)host_start, start - host_start);
 221             if (end < host_end)
 222                 munmap((void *)end, host_end - end);
 223             /* use it as a fixed mapping */
 224             flags |= MAP_FIXED;
 225         } else {
 226             /* if not fixed, no need to do anything */
 227             host_offset = offset & qemu_host_page_mask;
 228             host_len = len + offset - host_offset;
 229             start = (long)mmap((void *)host_start, host_len,
 230                                prot, flags, fd, host_offset);
 231             if (start == -1)
 232                 return start;
 233             /* update start so that it points to the file position at 'offset' */
 234             if (!(flags & MAP_ANONYMOUS))
 235                 start += offset - host_offset;
 236             goto the_end1;
 237         }
 238     }
 239
 240     if (start & ~TARGET_PAGE_MASK)
 241         return -EINVAL;
 242     end = start + len;
 243     host_end = HOST_PAGE_ALIGN(end);
 244
 245     /* worst case: we cannot map the file because the offset is not
 246        aligned, so we read it */
 247     if (!(flags & MAP_ANONYMOUS) &&
 248         (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) {
 249         /* msync() won't work here, so we return an error if write is
 250            possible while it is a shared mapping */
 251 #ifndef __APPLE__
 252         if ((flags & MAP_TYPE) == MAP_SHARED &&
 253 #else
 254         if ((flags & MAP_SHARED) &&
 255 #endif
 256             (prot & PROT_WRITE))
 257             return -EINVAL;
 258         retaddr = target_mmap(start, len, prot | PROT_WRITE,
 259                               MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
 260                               -1, 0);
 261         if (retaddr == -1)
 262             return retaddr;
 263         pread(fd, (void *)start, len, offset);
 264         if (!(prot & PROT_WRITE)) {
 265             ret = target_mprotect(start, len, prot);
 266             if (ret != 0)
 267                 return ret;
 268         }
 269         goto the_end;
 270     }
 271
 272     /* handle the start of the mapping */
 273     if (start > host_start) {
 274         if (host_end == host_start + qemu_host_page_size) {
 275             /* one single host page */
 276             ret = mmap_frag(host_start, start, end,
 277                             prot, flags, fd, offset);
 278             if (ret == -1)
 279                 return ret;
 280             goto the_end1;
 281         }
 282         ret = mmap_frag(host_start, start, host_start + qemu_host_page_size,
 283                         prot, flags, fd, offset);
 284         if (ret == -1)
 285             return ret;
 286         host_start += qemu_host_page_size;
 287     }
 288     /* handle the end of the mapping */
 289     if (end < host_end) {
 290         ret = mmap_frag(host_end - qemu_host_page_size,
 291                         host_end - qemu_host_page_size, host_end,
 292                         prot, flags, fd,
 293                         offset + host_end - qemu_host_page_size - start);
 294         if (ret == -1)
 295             return ret;
 296         host_end -= qemu_host_page_size;
 297     }
 298
 299     /* map the middle (easier) */
 300     if (host_start < host_end) {
 301         unsigned long offset1;
 302         if (flags & MAP_ANONYMOUS)
 303           offset1 = 0;
 304         else
 305           offset1 = offset + host_start - start;
 306         ret = (long)mmap((void *)host_start, host_end - host_start,
 307                          prot, flags, fd, offset1);
 308         if (ret == -1)
 309             return ret;
 310     }
 311  the_end1:
 312     page_set_flags(start, start + len, prot | PAGE_VALID);
 313  the_end:
 314 #ifdef DEBUG_MMAP
 315     printf("target_mmap: ret=0x%lx\n", (long)start);
 316     page_dump(stdout);
 317     printf("\n");
 318 #endif
 319     return start;
 320 }
 321
 322 int target_munmap(unsigned long start, unsigned long len)
 323 {
 324     unsigned long end, host_start, host_end, addr;
 325     int prot, ret;
 326
 327 #ifdef DEBUG_MMAP
 328     printf("munmap: start=0x%lx len=0x%lx\n", start, len);
 329 #endif
 330     if (start & ~TARGET_PAGE_MASK)
 331         return -EINVAL;
 332     len = TARGET_PAGE_ALIGN(len);
 333     if (len == 0)
 334         return -EINVAL;
 335     end = start + len;
 336     host_start = start & qemu_host_page_mask;
 337     host_end = HOST_PAGE_ALIGN(end);
 338
 339     if (start > host_start) {
 340         /* handle host page containing start */
 341         prot = 0;
 342         for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
 343             prot |= page_get_flags(addr);
 344         }
 345         if (host_end == host_start + qemu_host_page_size) {
 346             for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
 347                 prot |= page_get_flags(addr);
 348             }
 349             end = host_end;
 350         }
 351         if (prot != 0)
 352             host_start += qemu_host_page_size;
 353     }
 354     if (end < host_end) {
 355         prot = 0;
 356         for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
 357             prot |= page_get_flags(addr);
 358         }
 359         if (prot != 0)
 360             host_end -= qemu_host_page_size;
 361     }
 362
 363     /* unmap what we can */
 364     if (host_start < host_end) {
 365         ret = munmap((void *)host_start, host_end - host_start);
 366         if (ret != 0)
 367             return ret;
 368     }
 369
 370     page_set_flags(start, start + len, 0);
 371     return 0;
 372 }
 373
 374 /* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED
 375    blocks which have been allocated starting on a host page */
 376 long target_mremap(unsigned long old_addr, unsigned long old_size,
 377                    unsigned long new_size, unsigned long flags,
 378                    unsigned long new_addr)
 379 {
 380 #ifndef __APPLE__
 381     /* XXX: use 5 args syscall */
 382     new_addr = (long)mremap((void *)old_addr, old_size, new_size, flags);
 383     if (new_addr == -1)
 384         return new_addr;
 385     prot = page_get_flags(old_addr);
 386     page_set_flags(old_addr, old_addr + old_size, 0);
 387     page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
 388     return new_addr;
 389 #else
 390     qerror("target_mremap: unsupported\n");
 391 #endif
 392
 393 }
 394
 395 int target_msync(unsigned long start, unsigned long len, int flags)
 396 {
 397     unsigned long end;
 398
 399     if (start & ~TARGET_PAGE_MASK)
 400         return -EINVAL;
 401     len = TARGET_PAGE_ALIGN(len);
 402     end = start + len;
 403     if (end < start)
 404         return -EINVAL;
 405     if (end == start)
 406         return 0;
 407
 408     start &= qemu_host_page_mask;
 409     return msync((void *)start, end - start, flags);
 410 }
 411