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., 51 Franklin Street - Fifth Floor, Boston,
  19  *  MA 02110-1301, USA.
  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__)
 203         /* tell the kernel to search at the same place as i386 */
 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 }