1 /* 2 * mmap support for qemu 3 * 4 * Copyright (c) 2003 - 2008 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, see <http://www.gnu.org/licenses/>. 18 */ 19 #include "qemu/osdep.h" 20 21 #include "qemu.h" 22 #include "qemu-common.h" 23 24 static pthread_mutex_t mmap_mutex = PTHREAD_MUTEX_INITIALIZER; 25 static __thread int mmap_lock_count; 26 27 void mmap_lock(void) 28 { 29 if (mmap_lock_count++ == 0) { 30 pthread_mutex_lock(&mmap_mutex); 31 } 32 } 33 34 void mmap_unlock(void) 35 { 36 if (--mmap_lock_count == 0) { 37 pthread_mutex_unlock(&mmap_mutex); 38 } 39 } 40 41 bool have_mmap_lock(void) 42 { 43 return mmap_lock_count > 0 ? true : false; 44 } 45 46 /* Grab lock to make sure things are in a consistent state after fork(). */ 47 void mmap_fork_start(void) 48 { 49 if (mmap_lock_count) 50 abort(); 51 pthread_mutex_lock(&mmap_mutex); 52 } 53 54 void mmap_fork_end(int child) 55 { 56 if (child) 57 pthread_mutex_init(&mmap_mutex, NULL); 58 else 59 pthread_mutex_unlock(&mmap_mutex); 60 } 61 62 /* NOTE: all the constants are the HOST ones, but addresses are target. */ 63 int target_mprotect(abi_ulong start, abi_ulong len, int prot) 64 { 65 abi_ulong end, host_start, host_end, addr; 66 int prot1, ret; 67 68 qemu_log_mask(CPU_LOG_PAGE, "mprotect: start=0x" TARGET_ABI_FMT_lx 69 " len=0x" TARGET_ABI_FMT_lx " prot=%c%c%c\n", start, len, 70 prot & PROT_READ ? 'r' : '-', 71 prot & PROT_WRITE ? 'w' : '-', 72 prot & PROT_EXEC ? 'x' : '-'); 73 if ((start & ~TARGET_PAGE_MASK) != 0) 74 return -EINVAL; 75 len = TARGET_PAGE_ALIGN(len); 76 end = start + len; 77 if (end < start) 78 return -EINVAL; 79 prot &= PROT_READ | PROT_WRITE | PROT_EXEC; 80 if (len == 0) 81 return 0; 82 83 mmap_lock(); 84 host_start = start & qemu_host_page_mask; 85 host_end = HOST_PAGE_ALIGN(end); 86 if (start > host_start) { 87 /* handle host page containing start */ 88 prot1 = prot; 89 for (addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) { 90 prot1 |= page_get_flags(addr); 91 } 92 if (host_end == host_start + qemu_host_page_size) { 93 for (addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) { 94 prot1 |= page_get_flags(addr); 95 } 96 end = host_end; 97 } 98 ret = mprotect(g2h_untagged(host_start), 99 qemu_host_page_size, prot1 & PAGE_BITS); 100 if (ret != 0) 101 goto error; 102 host_start += qemu_host_page_size; 103 } 104 if (end < host_end) { 105 prot1 = prot; 106 for (addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) { 107 prot1 |= page_get_flags(addr); 108 } 109 ret = mprotect(g2h_untagged(host_end - qemu_host_page_size), 110 qemu_host_page_size, prot1 & PAGE_BITS); 111 if (ret != 0) 112 goto error; 113 host_end -= qemu_host_page_size; 114 } 115 116 /* handle the pages in the middle */ 117 if (host_start < host_end) { 118 ret = mprotect(g2h_untagged(host_start), host_end - host_start, prot); 119 if (ret != 0) 120 goto error; 121 } 122 page_set_flags(start, start + len, prot | PAGE_VALID); 123 mmap_unlock(); 124 return 0; 125 error: 126 mmap_unlock(); 127 return ret; 128 } 129 130 /* 131 * map an incomplete host page 132 * 133 * mmap_frag can be called with a valid fd, if flags doesn't contain one of 134 * MAP_ANON, MAP_STACK, MAP_GUARD. If we need to map a page in those cases, we 135 * pass fd == -1. However, if flags contains MAP_GUARD then MAP_ANON cannot be 136 * added. 137 * 138 * * If fd is valid (not -1) we want to map the pages with MAP_ANON. 139 * * If flags contains MAP_GUARD we don't want to add MAP_ANON because it 140 * will be rejected. See kern_mmap's enforcing of constraints for MAP_GUARD 141 * in sys/vm/vm_mmap.c. 142 * * If flags contains MAP_ANON it doesn't matter if we add it or not. 143 * * If flags contains MAP_STACK, mmap adds MAP_ANON when called so doesn't 144 * matter if we add it or not either. See enforcing of constraints for 145 * MAP_STACK in kern_mmap. 146 * 147 * Don't add MAP_ANON for the flags that use fd == -1 without specifying the 148 * flags directly, with the assumption that future flags that require fd == -1 149 * will also not require MAP_ANON. 150 */ 151 static int mmap_frag(abi_ulong real_start, 152 abi_ulong start, abi_ulong end, 153 int prot, int flags, int fd, abi_ulong offset) 154 { 155 abi_ulong real_end, addr; 156 void *host_start; 157 int prot1, prot_new; 158 159 real_end = real_start + qemu_host_page_size; 160 host_start = g2h_untagged(real_start); 161 162 /* get the protection of the target pages outside the mapping */ 163 prot1 = 0; 164 for (addr = real_start; addr < real_end; addr++) { 165 if (addr < start || addr >= end) 166 prot1 |= page_get_flags(addr); 167 } 168 169 if (prot1 == 0) { 170 /* no page was there, so we allocate one. See also above. */ 171 void *p = mmap(host_start, qemu_host_page_size, prot, 172 flags | ((fd != -1) ? MAP_ANON : 0), -1, 0); 173 if (p == MAP_FAILED) 174 return -1; 175 prot1 = prot; 176 } 177 prot1 &= PAGE_BITS; 178 179 prot_new = prot | prot1; 180 if (fd != -1) { 181 /* msync() won't work here, so we return an error if write is 182 possible while it is a shared mapping */ 183 if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED && 184 (prot & PROT_WRITE)) 185 return -1; 186 187 /* adjust protection to be able to read */ 188 if (!(prot1 & PROT_WRITE)) 189 mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE); 190 191 /* read the corresponding file data */ 192 if (pread(fd, g2h_untagged(start), end - start, offset) == -1) { 193 return -1; 194 } 195 196 /* put final protection */ 197 if (prot_new != (prot1 | PROT_WRITE)) 198 mprotect(host_start, qemu_host_page_size, prot_new); 199 } else { 200 if (prot_new != prot1) { 201 mprotect(host_start, qemu_host_page_size, prot_new); 202 } 203 if (prot_new & PROT_WRITE) { 204 memset(g2h_untagged(start), 0, end - start); 205 } 206 } 207 return 0; 208 } 209 210 #if HOST_LONG_BITS == 64 && TARGET_ABI_BITS == 64 211 # define TASK_UNMAPPED_BASE (1ul << 38) 212 #else 213 # define TASK_UNMAPPED_BASE 0x40000000 214 #endif 215 abi_ulong mmap_next_start = TASK_UNMAPPED_BASE; 216 217 unsigned long last_brk; 218 219 /* 220 * Subroutine of mmap_find_vma, used when we have pre-allocated a chunk of guest 221 * address space. 222 */ 223 static abi_ulong mmap_find_vma_reserved(abi_ulong start, abi_ulong size, 224 abi_ulong alignment) 225 { 226 abi_ulong addr; 227 abi_ulong end_addr; 228 int prot; 229 int looped = 0; 230 231 if (size > reserved_va) { 232 return (abi_ulong)-1; 233 } 234 235 size = HOST_PAGE_ALIGN(size) + alignment; 236 end_addr = start + size; 237 if (end_addr > reserved_va) { 238 end_addr = reserved_va; 239 } 240 addr = end_addr - qemu_host_page_size; 241 242 while (1) { 243 if (addr > end_addr) { 244 if (looped) { 245 return (abi_ulong)-1; 246 } 247 end_addr = reserved_va; 248 addr = end_addr - qemu_host_page_size; 249 looped = 1; 250 continue; 251 } 252 prot = page_get_flags(addr); 253 if (prot) { 254 end_addr = addr; 255 } 256 if (end_addr - addr >= size) { 257 break; 258 } 259 addr -= qemu_host_page_size; 260 } 261 262 if (start == mmap_next_start) { 263 mmap_next_start = addr; 264 } 265 /* addr is sufficiently low to align it up */ 266 if (alignment != 0) { 267 addr = (addr + alignment) & ~(alignment - 1); 268 } 269 return addr; 270 } 271 272 /* 273 * Find and reserve a free memory area of size 'size'. The search 274 * starts at 'start'. 275 * It must be called with mmap_lock() held. 276 * Return -1 if error. 277 */ 278 static abi_ulong mmap_find_vma_aligned(abi_ulong start, abi_ulong size, 279 abi_ulong alignment) 280 { 281 void *ptr, *prev; 282 abi_ulong addr; 283 int flags; 284 int wrapped, repeat; 285 286 /* If 'start' == 0, then a default start address is used. */ 287 if (start == 0) { 288 start = mmap_next_start; 289 } else { 290 start &= qemu_host_page_mask; 291 } 292 293 size = HOST_PAGE_ALIGN(size); 294 295 if (reserved_va) { 296 return mmap_find_vma_reserved(start, size, 297 (alignment != 0 ? 1 << alignment : 0)); 298 } 299 300 addr = start; 301 wrapped = repeat = 0; 302 prev = 0; 303 flags = MAP_ANON | MAP_PRIVATE; 304 if (alignment != 0) { 305 flags |= MAP_ALIGNED(alignment); 306 } 307 308 for (;; prev = ptr) { 309 /* 310 * Reserve needed memory area to avoid a race. 311 * It should be discarded using: 312 * - mmap() with MAP_FIXED flag 313 * - mremap() with MREMAP_FIXED flag 314 * - shmat() with SHM_REMAP flag 315 */ 316 ptr = mmap(g2h_untagged(addr), size, PROT_NONE, 317 flags, -1, 0); 318 319 /* ENOMEM, if host address space has no memory */ 320 if (ptr == MAP_FAILED) { 321 return (abi_ulong)-1; 322 } 323 324 /* 325 * Count the number of sequential returns of the same address. 326 * This is used to modify the search algorithm below. 327 */ 328 repeat = (ptr == prev ? repeat + 1 : 0); 329 330 if (h2g_valid(ptr + size - 1)) { 331 addr = h2g(ptr); 332 333 if ((addr & ~TARGET_PAGE_MASK) == 0) { 334 /* Success. */ 335 if (start == mmap_next_start && addr >= TASK_UNMAPPED_BASE) { 336 mmap_next_start = addr + size; 337 } 338 return addr; 339 } 340 341 /* The address is not properly aligned for the target. */ 342 switch (repeat) { 343 case 0: 344 /* 345 * Assume the result that the kernel gave us is the 346 * first with enough free space, so start again at the 347 * next higher target page. 348 */ 349 addr = TARGET_PAGE_ALIGN(addr); 350 break; 351 case 1: 352 /* 353 * Sometimes the kernel decides to perform the allocation 354 * at the top end of memory instead. 355 */ 356 addr &= TARGET_PAGE_MASK; 357 break; 358 case 2: 359 /* Start over at low memory. */ 360 addr = 0; 361 break; 362 default: 363 /* Fail. This unaligned block must the last. */ 364 addr = -1; 365 break; 366 } 367 } else { 368 /* 369 * Since the result the kernel gave didn't fit, start 370 * again at low memory. If any repetition, fail. 371 */ 372 addr = (repeat ? -1 : 0); 373 } 374 375 /* Unmap and try again. */ 376 munmap(ptr, size); 377 378 /* ENOMEM if we checked the whole of the target address space. */ 379 if (addr == (abi_ulong)-1) { 380 return (abi_ulong)-1; 381 } else if (addr == 0) { 382 if (wrapped) { 383 return (abi_ulong)-1; 384 } 385 wrapped = 1; 386 /* 387 * Don't actually use 0 when wrapping, instead indicate 388 * that we'd truly like an allocation in low memory. 389 */ 390 addr = TARGET_PAGE_SIZE; 391 } else if (wrapped && addr >= start) { 392 return (abi_ulong)-1; 393 } 394 } 395 } 396 397 abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size) 398 { 399 return mmap_find_vma_aligned(start, size, 0); 400 } 401 402 /* NOTE: all the constants are the HOST ones */ 403 abi_long target_mmap(abi_ulong start, abi_ulong len, int prot, 404 int flags, int fd, off_t offset) 405 { 406 abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len; 407 408 mmap_lock(); 409 if (qemu_loglevel_mask(CPU_LOG_PAGE)) { 410 qemu_log("mmap: start=0x" TARGET_ABI_FMT_lx 411 " len=0x" TARGET_ABI_FMT_lx " prot=%c%c%c flags=", 412 start, len, 413 prot & PROT_READ ? 'r' : '-', 414 prot & PROT_WRITE ? 'w' : '-', 415 prot & PROT_EXEC ? 'x' : '-'); 416 if (flags & MAP_ALIGNMENT_MASK) { 417 qemu_log("MAP_ALIGNED(%u) ", 418 (flags & MAP_ALIGNMENT_MASK) >> MAP_ALIGNMENT_SHIFT); 419 } 420 if (flags & MAP_GUARD) { 421 qemu_log("MAP_GUARD "); 422 } 423 if (flags & MAP_FIXED) { 424 qemu_log("MAP_FIXED "); 425 } 426 if (flags & MAP_ANON) { 427 qemu_log("MAP_ANON "); 428 } 429 if (flags & MAP_EXCL) { 430 qemu_log("MAP_EXCL "); 431 } 432 if (flags & MAP_PRIVATE) { 433 qemu_log("MAP_PRIVATE "); 434 } 435 if (flags & MAP_SHARED) { 436 qemu_log("MAP_SHARED "); 437 } 438 if (flags & MAP_NOCORE) { 439 qemu_log("MAP_NOCORE "); 440 } 441 if (flags & MAP_STACK) { 442 qemu_log("MAP_STACK "); 443 } 444 qemu_log("fd=%d offset=0x%lx\n", fd, offset); 445 } 446 447 if ((flags & MAP_ANON) && fd != -1) { 448 errno = EINVAL; 449 goto fail; 450 } 451 if (flags & MAP_STACK) { 452 if ((fd != -1) || ((prot & (PROT_READ | PROT_WRITE)) != 453 (PROT_READ | PROT_WRITE))) { 454 errno = EINVAL; 455 goto fail; 456 } 457 } 458 if ((flags & MAP_GUARD) && (prot != PROT_NONE || fd != -1 || 459 offset != 0 || (flags & (MAP_SHARED | MAP_PRIVATE | 460 /* MAP_PREFAULT | */ /* MAP_PREFAULT not in mman.h */ 461 MAP_PREFAULT_READ | MAP_ANON | MAP_STACK)) != 0)) { 462 errno = EINVAL; 463 goto fail; 464 } 465 466 if (offset & ~TARGET_PAGE_MASK) { 467 errno = EINVAL; 468 goto fail; 469 } 470 471 if (len == 0) { 472 errno = EINVAL; 473 goto fail; 474 } 475 476 /* Check for overflows */ 477 len = TARGET_PAGE_ALIGN(len); 478 if (len == 0) { 479 errno = ENOMEM; 480 goto fail; 481 } 482 483 real_start = start & qemu_host_page_mask; 484 host_offset = offset & qemu_host_page_mask; 485 486 /* 487 * If the user is asking for the kernel to find a location, do that 488 * before we truncate the length for mapping files below. 489 */ 490 if (!(flags & MAP_FIXED)) { 491 host_len = len + offset - host_offset; 492 host_len = HOST_PAGE_ALIGN(host_len); 493 if ((flags & MAP_ALIGNMENT_MASK) != 0) 494 start = mmap_find_vma_aligned(real_start, host_len, 495 (flags & MAP_ALIGNMENT_MASK) >> MAP_ALIGNMENT_SHIFT); 496 else 497 start = mmap_find_vma(real_start, host_len); 498 if (start == (abi_ulong)-1) { 499 errno = ENOMEM; 500 goto fail; 501 } 502 } 503 504 /* 505 * When mapping files into a memory area larger than the file, accesses 506 * to pages beyond the file size will cause a SIGBUS. 507 * 508 * For example, if mmaping a file of 100 bytes on a host with 4K pages 509 * emulating a target with 8K pages, the target expects to be able to 510 * access the first 8K. But the host will trap us on any access beyond 511 * 4K. 512 * 513 * When emulating a target with a larger page-size than the hosts, we 514 * may need to truncate file maps at EOF and add extra anonymous pages 515 * up to the targets page boundary. 516 */ 517 518 if ((qemu_real_host_page_size < qemu_host_page_size) && fd != -1) { 519 struct stat sb; 520 521 if (fstat(fd, &sb) == -1) { 522 goto fail; 523 } 524 525 /* Are we trying to create a map beyond EOF?. */ 526 if (offset + len > sb.st_size) { 527 /* 528 * If so, truncate the file map at eof aligned with 529 * the hosts real pagesize. Additional anonymous maps 530 * will be created beyond EOF. 531 */ 532 len = REAL_HOST_PAGE_ALIGN(sb.st_size - offset); 533 } 534 } 535 536 if (!(flags & MAP_FIXED)) { 537 unsigned long host_start; 538 void *p; 539 540 host_len = len + offset - host_offset; 541 host_len = HOST_PAGE_ALIGN(host_len); 542 543 /* 544 * Note: we prefer to control the mapping address. It is 545 * especially important if qemu_host_page_size > 546 * qemu_real_host_page_size 547 */ 548 p = mmap(g2h_untagged(start), host_len, prot, 549 flags | MAP_FIXED | ((fd != -1) ? MAP_ANON : 0), -1, 0); 550 if (p == MAP_FAILED) 551 goto fail; 552 /* update start so that it points to the file position at 'offset' */ 553 host_start = (unsigned long)p; 554 if (fd != -1) { 555 p = mmap(g2h_untagged(start), len, prot, 556 flags | MAP_FIXED, fd, host_offset); 557 if (p == MAP_FAILED) { 558 munmap(g2h_untagged(start), host_len); 559 goto fail; 560 } 561 host_start += offset - host_offset; 562 } 563 start = h2g(host_start); 564 } else { 565 if (start & ~TARGET_PAGE_MASK) { 566 errno = EINVAL; 567 goto fail; 568 } 569 end = start + len; 570 real_end = HOST_PAGE_ALIGN(end); 571 572 /* 573 * Test if requested memory area fits target address space 574 * It can fail only on 64-bit host with 32-bit target. 575 * On any other target/host host mmap() handles this error correctly. 576 */ 577 if (!guest_range_valid_untagged(start, len)) { 578 errno = EINVAL; 579 goto fail; 580 } 581 582 /* 583 * worst case: we cannot map the file because the offset is not 584 * aligned, so we read it 585 */ 586 if (fd != -1 && 587 (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) { 588 /* 589 * msync() won't work here, so we return an error if write is 590 * possible while it is a shared mapping 591 */ 592 if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED && 593 (prot & PROT_WRITE)) { 594 errno = EINVAL; 595 goto fail; 596 } 597 retaddr = target_mmap(start, len, prot | PROT_WRITE, 598 MAP_FIXED | MAP_PRIVATE | MAP_ANON, 599 -1, 0); 600 if (retaddr == -1) 601 goto fail; 602 if (pread(fd, g2h_untagged(start), len, offset) == -1) { 603 goto fail; 604 } 605 if (!(prot & PROT_WRITE)) { 606 ret = target_mprotect(start, len, prot); 607 assert(ret == 0); 608 } 609 goto the_end; 610 } 611 612 /* Reject the mapping if any page within the range is mapped */ 613 if ((flags & MAP_EXCL) && page_check_range(start, len, 0) < 0) { 614 errno = EINVAL; 615 goto fail; 616 } 617 618 /* handle the start of the mapping */ 619 if (start > real_start) { 620 if (real_end == real_start + qemu_host_page_size) { 621 /* one single host page */ 622 ret = mmap_frag(real_start, start, end, 623 prot, flags, fd, offset); 624 if (ret == -1) 625 goto fail; 626 goto the_end1; 627 } 628 ret = mmap_frag(real_start, start, real_start + qemu_host_page_size, 629 prot, flags, fd, offset); 630 if (ret == -1) 631 goto fail; 632 real_start += qemu_host_page_size; 633 } 634 /* handle the end of the mapping */ 635 if (end < real_end) { 636 ret = mmap_frag(real_end - qemu_host_page_size, 637 real_end - qemu_host_page_size, end, 638 prot, flags, fd, 639 offset + real_end - qemu_host_page_size - start); 640 if (ret == -1) 641 goto fail; 642 real_end -= qemu_host_page_size; 643 } 644 645 /* map the middle (easier) */ 646 if (real_start < real_end) { 647 void *p; 648 unsigned long offset1; 649 if (flags & MAP_ANON) 650 offset1 = 0; 651 else 652 offset1 = offset + real_start - start; 653 p = mmap(g2h_untagged(real_start), real_end - real_start, 654 prot, flags, fd, offset1); 655 if (p == MAP_FAILED) 656 goto fail; 657 } 658 } 659 the_end1: 660 page_set_flags(start, start + len, prot | PAGE_VALID); 661 the_end: 662 #ifdef DEBUG_MMAP 663 printf("ret=0x" TARGET_ABI_FMT_lx "\n", start); 664 page_dump(stdout); 665 printf("\n"); 666 #endif 667 tb_invalidate_phys_range(start, start + len); 668 mmap_unlock(); 669 return start; 670 fail: 671 mmap_unlock(); 672 return -1; 673 } 674 675 static void mmap_reserve(abi_ulong start, abi_ulong size) 676 { 677 abi_ulong real_start; 678 abi_ulong real_end; 679 abi_ulong addr; 680 abi_ulong end; 681 int prot; 682 683 real_start = start & qemu_host_page_mask; 684 real_end = HOST_PAGE_ALIGN(start + size); 685 end = start + size; 686 if (start > real_start) { 687 /* handle host page containing start */ 688 prot = 0; 689 for (addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) { 690 prot |= page_get_flags(addr); 691 } 692 if (real_end == real_start + qemu_host_page_size) { 693 for (addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { 694 prot |= page_get_flags(addr); 695 } 696 end = real_end; 697 } 698 if (prot != 0) { 699 real_start += qemu_host_page_size; 700 } 701 } 702 if (end < real_end) { 703 prot = 0; 704 for (addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { 705 prot |= page_get_flags(addr); 706 } 707 if (prot != 0) { 708 real_end -= qemu_host_page_size; 709 } 710 } 711 if (real_start != real_end) { 712 mmap(g2h_untagged(real_start), real_end - real_start, PROT_NONE, 713 MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0); 714 } 715 } 716 717 int target_munmap(abi_ulong start, abi_ulong len) 718 { 719 abi_ulong end, real_start, real_end, addr; 720 int prot, ret; 721 722 #ifdef DEBUG_MMAP 723 printf("munmap: start=0x" TARGET_ABI_FMT_lx " len=0x" 724 TARGET_ABI_FMT_lx "\n", 725 start, len); 726 #endif 727 if (start & ~TARGET_PAGE_MASK) 728 return -EINVAL; 729 len = TARGET_PAGE_ALIGN(len); 730 if (len == 0) 731 return -EINVAL; 732 mmap_lock(); 733 end = start + len; 734 real_start = start & qemu_host_page_mask; 735 real_end = HOST_PAGE_ALIGN(end); 736 737 if (start > real_start) { 738 /* handle host page containing start */ 739 prot = 0; 740 for (addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) { 741 prot |= page_get_flags(addr); 742 } 743 if (real_end == real_start + qemu_host_page_size) { 744 for (addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { 745 prot |= page_get_flags(addr); 746 } 747 end = real_end; 748 } 749 if (prot != 0) 750 real_start += qemu_host_page_size; 751 } 752 if (end < real_end) { 753 prot = 0; 754 for (addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { 755 prot |= page_get_flags(addr); 756 } 757 if (prot != 0) 758 real_end -= qemu_host_page_size; 759 } 760 761 ret = 0; 762 /* unmap what we can */ 763 if (real_start < real_end) { 764 if (reserved_va) { 765 mmap_reserve(real_start, real_end - real_start); 766 } else { 767 ret = munmap(g2h_untagged(real_start), real_end - real_start); 768 } 769 } 770 771 if (ret == 0) { 772 page_set_flags(start, start + len, 0); 773 tb_invalidate_phys_range(start, start + len); 774 } 775 mmap_unlock(); 776 return ret; 777 } 778 779 int target_msync(abi_ulong start, abi_ulong len, int flags) 780 { 781 abi_ulong end; 782 783 if (start & ~TARGET_PAGE_MASK) 784 return -EINVAL; 785 len = TARGET_PAGE_ALIGN(len); 786 end = start + len; 787 if (end < start) 788 return -EINVAL; 789 if (end == start) 790 return 0; 791 792 start &= qemu_host_page_mask; 793 return msync(g2h_untagged(start), end - start, flags); 794 } 795