mmap.c (23237B)
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//#define DEBUG_MMAP 25 26static pthread_mutex_t mmap_mutex = PTHREAD_MUTEX_INITIALIZER; 27static __thread int mmap_lock_count; 28 29void mmap_lock(void) 30{ 31 if (mmap_lock_count++ == 0) { 32 pthread_mutex_lock(&mmap_mutex); 33 } 34} 35 36void mmap_unlock(void) 37{ 38 if (--mmap_lock_count == 0) { 39 pthread_mutex_unlock(&mmap_mutex); 40 } 41} 42 43bool have_mmap_lock(void) 44{ 45 return mmap_lock_count > 0 ? true : false; 46} 47 48/* Grab lock to make sure things are in a consistent state after fork(). */ 49void mmap_fork_start(void) 50{ 51 if (mmap_lock_count) 52 abort(); 53 pthread_mutex_lock(&mmap_mutex); 54} 55 56void mmap_fork_end(int child) 57{ 58 if (child) 59 pthread_mutex_init(&mmap_mutex, NULL); 60 else 61 pthread_mutex_unlock(&mmap_mutex); 62} 63 64/* NOTE: all the constants are the HOST ones, but addresses are target. */ 65int target_mprotect(abi_ulong start, abi_ulong len, int prot) 66{ 67 abi_ulong end, host_start, host_end, addr; 68 int prot1, ret; 69 70#ifdef DEBUG_MMAP 71 printf("mprotect: start=0x" TARGET_ABI_FMT_lx 72 "len=0x" TARGET_ABI_FMT_lx " prot=%c%c%c\n", start, len, 73 prot & PROT_READ ? 'r' : '-', 74 prot & PROT_WRITE ? 'w' : '-', 75 prot & PROT_EXEC ? 'x' : '-'); 76#endif 77 78 if ((start & ~TARGET_PAGE_MASK) != 0) 79 return -EINVAL; 80 len = TARGET_PAGE_ALIGN(len); 81 end = start + len; 82 if (end < start) 83 return -EINVAL; 84 prot &= PROT_READ | PROT_WRITE | PROT_EXEC; 85 if (len == 0) 86 return 0; 87 88 mmap_lock(); 89 host_start = start & qemu_host_page_mask; 90 host_end = HOST_PAGE_ALIGN(end); 91 if (start > host_start) { 92 /* handle host page containing start */ 93 prot1 = prot; 94 for (addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) { 95 prot1 |= page_get_flags(addr); 96 } 97 if (host_end == host_start + qemu_host_page_size) { 98 for (addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) { 99 prot1 |= page_get_flags(addr); 100 } 101 end = host_end; 102 } 103 ret = mprotect(g2h_untagged(host_start), 104 qemu_host_page_size, prot1 & PAGE_BITS); 105 if (ret != 0) 106 goto error; 107 host_start += qemu_host_page_size; 108 } 109 if (end < host_end) { 110 prot1 = prot; 111 for (addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) { 112 prot1 |= page_get_flags(addr); 113 } 114 ret = mprotect(g2h_untagged(host_end - qemu_host_page_size), 115 qemu_host_page_size, prot1 & PAGE_BITS); 116 if (ret != 0) 117 goto error; 118 host_end -= qemu_host_page_size; 119 } 120 121 /* handle the pages in the middle */ 122 if (host_start < host_end) { 123 ret = mprotect(g2h_untagged(host_start), host_end - host_start, prot); 124 if (ret != 0) 125 goto error; 126 } 127 page_set_flags(start, start + len, prot | PAGE_VALID); 128 mmap_unlock(); 129 return 0; 130error: 131 mmap_unlock(); 132 return ret; 133} 134 135/* map an incomplete host page */ 136static int mmap_frag(abi_ulong real_start, 137 abi_ulong start, abi_ulong end, 138 int prot, int flags, int fd, abi_ulong offset) 139{ 140 abi_ulong real_end, addr; 141 void *host_start; 142 int prot1, prot_new; 143 144 real_end = real_start + qemu_host_page_size; 145 host_start = g2h_untagged(real_start); 146 147 /* get the protection of the target pages outside the mapping */ 148 prot1 = 0; 149 for (addr = real_start; addr < real_end; addr++) { 150 if (addr < start || addr >= end) 151 prot1 |= page_get_flags(addr); 152 } 153 154 if (prot1 == 0) { 155 /* no page was there, so we allocate one */ 156 void *p = mmap(host_start, qemu_host_page_size, prot, 157 flags | MAP_ANON, -1, 0); 158 if (p == MAP_FAILED) 159 return -1; 160 prot1 = prot; 161 } 162 prot1 &= PAGE_BITS; 163 164 prot_new = prot | prot1; 165 if (!(flags & MAP_ANON)) { 166 /* msync() won't work here, so we return an error if write is 167 possible while it is a shared mapping */ 168 if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED && 169 (prot & PROT_WRITE)) 170 return -1; 171 172 /* adjust protection to be able to read */ 173 if (!(prot1 & PROT_WRITE)) 174 mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE); 175 176 /* read the corresponding file data */ 177 pread(fd, g2h_untagged(start), end - start, offset); 178 179 /* put final protection */ 180 if (prot_new != (prot1 | PROT_WRITE)) 181 mprotect(host_start, qemu_host_page_size, prot_new); 182 } else { 183 /* just update the protection */ 184 if (prot_new != prot1) { 185 mprotect(host_start, qemu_host_page_size, prot_new); 186 } 187 } 188 return 0; 189} 190 191#if HOST_LONG_BITS == 64 && TARGET_ABI_BITS == 64 192# define TASK_UNMAPPED_BASE (1ul << 38) 193#else 194# define TASK_UNMAPPED_BASE 0x40000000 195#endif 196abi_ulong mmap_next_start = TASK_UNMAPPED_BASE; 197 198unsigned long last_brk; 199 200/* 201 * Subroutine of mmap_find_vma, used when we have pre-allocated a chunk of guest 202 * address space. 203 */ 204static abi_ulong mmap_find_vma_reserved(abi_ulong start, abi_ulong size, 205 abi_ulong alignment) 206{ 207 abi_ulong addr; 208 abi_ulong end_addr; 209 int prot; 210 int looped = 0; 211 212 if (size > reserved_va) { 213 return (abi_ulong)-1; 214 } 215 216 size = HOST_PAGE_ALIGN(size) + alignment; 217 end_addr = start + size; 218 if (end_addr > reserved_va) { 219 end_addr = reserved_va; 220 } 221 addr = end_addr - qemu_host_page_size; 222 223 while (1) { 224 if (addr > end_addr) { 225 if (looped) { 226 return (abi_ulong)-1; 227 } 228 end_addr = reserved_va; 229 addr = end_addr - qemu_host_page_size; 230 looped = 1; 231 continue; 232 } 233 prot = page_get_flags(addr); 234 if (prot) { 235 end_addr = addr; 236 } 237 if (end_addr - addr >= size) { 238 break; 239 } 240 addr -= qemu_host_page_size; 241 } 242 243 if (start == mmap_next_start) { 244 mmap_next_start = addr; 245 } 246 /* addr is sufficiently low to align it up */ 247 if (alignment != 0) { 248 addr = (addr + alignment) & ~(alignment - 1); 249 } 250 return addr; 251} 252 253/* 254 * Find and reserve a free memory area of size 'size'. The search 255 * starts at 'start'. 256 * It must be called with mmap_lock() held. 257 * Return -1 if error. 258 */ 259static abi_ulong mmap_find_vma_aligned(abi_ulong start, abi_ulong size, 260 abi_ulong alignment) 261{ 262 void *ptr, *prev; 263 abi_ulong addr; 264 int flags; 265 int wrapped, repeat; 266 267 /* If 'start' == 0, then a default start address is used. */ 268 if (start == 0) { 269 start = mmap_next_start; 270 } else { 271 start &= qemu_host_page_mask; 272 } 273 274 size = HOST_PAGE_ALIGN(size); 275 276 if (reserved_va) { 277 return mmap_find_vma_reserved(start, size, 278 (alignment != 0 ? 1 << alignment : 0)); 279 } 280 281 addr = start; 282 wrapped = repeat = 0; 283 prev = 0; 284 flags = MAP_ANONYMOUS | MAP_PRIVATE; 285#ifdef MAP_ALIGNED 286 if (alignment != 0) { 287 flags |= MAP_ALIGNED(alignment); 288 } 289#else 290 /* XXX TODO */ 291#endif 292 293 for (;; prev = ptr) { 294 /* 295 * Reserve needed memory area to avoid a race. 296 * It should be discarded using: 297 * - mmap() with MAP_FIXED flag 298 * - mremap() with MREMAP_FIXED flag 299 * - shmat() with SHM_REMAP flag 300 */ 301 ptr = mmap(g2h_untagged(addr), size, PROT_NONE, 302 flags, -1, 0); 303 304 /* ENOMEM, if host address space has no memory */ 305 if (ptr == MAP_FAILED) { 306 return (abi_ulong)-1; 307 } 308 309 /* 310 * Count the number of sequential returns of the same address. 311 * This is used to modify the search algorithm below. 312 */ 313 repeat = (ptr == prev ? repeat + 1 : 0); 314 315 if (h2g_valid(ptr + size - 1)) { 316 addr = h2g(ptr); 317 318 if ((addr & ~TARGET_PAGE_MASK) == 0) { 319 /* Success. */ 320 if (start == mmap_next_start && addr >= TASK_UNMAPPED_BASE) { 321 mmap_next_start = addr + size; 322 } 323 return addr; 324 } 325 326 /* The address is not properly aligned for the target. */ 327 switch (repeat) { 328 case 0: 329 /* 330 * Assume the result that the kernel gave us is the 331 * first with enough free space, so start again at the 332 * next higher target page. 333 */ 334 addr = TARGET_PAGE_ALIGN(addr); 335 break; 336 case 1: 337 /* 338 * Sometimes the kernel decides to perform the allocation 339 * at the top end of memory instead. 340 */ 341 addr &= TARGET_PAGE_MASK; 342 break; 343 case 2: 344 /* Start over at low memory. */ 345 addr = 0; 346 break; 347 default: 348 /* Fail. This unaligned block must the last. */ 349 addr = -1; 350 break; 351 } 352 } else { 353 /* 354 * Since the result the kernel gave didn't fit, start 355 * again at low memory. If any repetition, fail. 356 */ 357 addr = (repeat ? -1 : 0); 358 } 359 360 /* Unmap and try again. */ 361 munmap(ptr, size); 362 363 /* ENOMEM if we checked the whole of the target address space. */ 364 if (addr == (abi_ulong)-1) { 365 return (abi_ulong)-1; 366 } else if (addr == 0) { 367 if (wrapped) { 368 return (abi_ulong)-1; 369 } 370 wrapped = 1; 371 /* 372 * Don't actually use 0 when wrapping, instead indicate 373 * that we'd truly like an allocation in low memory. 374 */ 375 addr = TARGET_PAGE_SIZE; 376 } else if (wrapped && addr >= start) { 377 return (abi_ulong)-1; 378 } 379 } 380} 381 382abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size) 383{ 384 return mmap_find_vma_aligned(start, size, 0); 385} 386 387/* NOTE: all the constants are the HOST ones */ 388abi_long target_mmap(abi_ulong start, abi_ulong len, int prot, 389 int flags, int fd, off_t offset) 390{ 391 abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len; 392 393 mmap_lock(); 394#ifdef DEBUG_MMAP 395 { 396 printf("mmap: start=0x" TARGET_ABI_FMT_lx 397 " len=0x" TARGET_ABI_FMT_lx " prot=%c%c%c flags=", 398 start, len, 399 prot & PROT_READ ? 'r' : '-', 400 prot & PROT_WRITE ? 'w' : '-', 401 prot & PROT_EXEC ? 'x' : '-'); 402 if (flags & MAP_ALIGNMENT_MASK) { 403 printf("MAP_ALIGNED(%u) ", (flags & MAP_ALIGNMENT_MASK) 404 >> MAP_ALIGNMENT_SHIFT); 405 } 406#if MAP_GUARD 407 if (flags & MAP_GUARD) { 408 printf("MAP_GUARD "); 409 } 410#endif 411 if (flags & MAP_FIXED) { 412 printf("MAP_FIXED "); 413 } 414 if (flags & MAP_ANONYMOUS) { 415 printf("MAP_ANON "); 416 } 417#ifdef MAP_EXCL 418 if (flags & MAP_EXCL) { 419 printf("MAP_EXCL "); 420 } 421#endif 422 if (flags & MAP_PRIVATE) { 423 printf("MAP_PRIVATE "); 424 } 425 if (flags & MAP_SHARED) { 426 printf("MAP_SHARED "); 427 } 428 if (flags & MAP_NOCORE) { 429 printf("MAP_NOCORE "); 430 } 431#ifdef MAP_STACK 432 if (flags & MAP_STACK) { 433 printf("MAP_STACK "); 434 } 435#endif 436 printf("fd=%d offset=0x%llx\n", fd, offset); 437 } 438#endif 439 440 if ((flags & MAP_ANONYMOUS) && fd != -1) { 441 errno = EINVAL; 442 goto fail; 443 } 444#ifdef MAP_STACK 445 if (flags & MAP_STACK) { 446 if ((fd != -1) || ((prot & (PROT_READ | PROT_WRITE)) != 447 (PROT_READ | PROT_WRITE))) { 448 errno = EINVAL; 449 goto fail; 450 } 451 } 452#endif /* MAP_STACK */ 453#ifdef MAP_GUARD 454 if ((flags & MAP_GUARD) && (prot != PROT_NONE || fd != -1 || 455 offset != 0 || (flags & (MAP_SHARED | MAP_PRIVATE | 456 /* MAP_PREFAULT | */ /* MAP_PREFAULT not in mman.h */ 457 MAP_PREFAULT_READ | MAP_ANON | MAP_STACK)) != 0)) { 458 errno = EINVAL; 459 goto fail; 460 } 461#endif 462 463 if (offset & ~TARGET_PAGE_MASK) { 464 errno = EINVAL; 465 goto fail; 466 } 467 468 len = TARGET_PAGE_ALIGN(len); 469 if (len == 0) { 470 errno = EINVAL; 471 goto fail; 472 } 473 real_start = start & qemu_host_page_mask; 474 host_offset = offset & qemu_host_page_mask; 475 476 /* 477 * If the user is asking for the kernel to find a location, do that 478 * before we truncate the length for mapping files below. 479 */ 480 if (!(flags & MAP_FIXED)) { 481 host_len = len + offset - host_offset; 482 host_len = HOST_PAGE_ALIGN(host_len); 483 if ((flags & MAP_ALIGNMENT_MASK) != 0) 484 start = mmap_find_vma_aligned(real_start, host_len, 485 (flags & MAP_ALIGNMENT_MASK) >> MAP_ALIGNMENT_SHIFT); 486 else 487 start = mmap_find_vma(real_start, host_len); 488 if (start == (abi_ulong)-1) { 489 errno = ENOMEM; 490 goto fail; 491 } 492 } 493 494 /* 495 * When mapping files into a memory area larger than the file, accesses 496 * to pages beyond the file size will cause a SIGBUS. 497 * 498 * For example, if mmaping a file of 100 bytes on a host with 4K pages 499 * emulating a target with 8K pages, the target expects to be able to 500 * access the first 8K. But the host will trap us on any access beyond 501 * 4K. 502 * 503 * When emulating a target with a larger page-size than the hosts, we 504 * may need to truncate file maps at EOF and add extra anonymous pages 505 * up to the targets page boundary. 506 */ 507 508 if ((qemu_real_host_page_size < qemu_host_page_size) && fd != -1) { 509 struct stat sb; 510 511 if (fstat(fd, &sb) == -1) { 512 goto fail; 513 } 514 515 /* Are we trying to create a map beyond EOF?. */ 516 if (offset + len > sb.st_size) { 517 /* 518 * If so, truncate the file map at eof aligned with 519 * the hosts real pagesize. Additional anonymous maps 520 * will be created beyond EOF. 521 */ 522 len = REAL_HOST_PAGE_ALIGN(sb.st_size - offset); 523 } 524 } 525 526 if (!(flags & MAP_FIXED)) { 527 unsigned long host_start; 528 void *p; 529 530 host_len = len + offset - host_offset; 531 host_len = HOST_PAGE_ALIGN(host_len); 532 533 /* 534 * Note: we prefer to control the mapping address. It is 535 * especially important if qemu_host_page_size > 536 * qemu_real_host_page_size 537 */ 538 p = mmap(g2h_untagged(start), host_len, prot, 539 flags | MAP_FIXED | ((fd != -1) ? MAP_ANONYMOUS : 0), -1, 0); 540 if (p == MAP_FAILED) 541 goto fail; 542 /* update start so that it points to the file position at 'offset' */ 543 host_start = (unsigned long)p; 544 if (fd != -1) { 545 p = mmap(g2h_untagged(start), len, prot, 546 flags | MAP_FIXED, fd, host_offset); 547 if (p == MAP_FAILED) { 548 munmap(g2h_untagged(start), host_len); 549 goto fail; 550 } 551 host_start += offset - host_offset; 552 } 553 start = h2g(host_start); 554 } else { 555 if (start & ~TARGET_PAGE_MASK) { 556 errno = EINVAL; 557 goto fail; 558 } 559 end = start + len; 560 real_end = HOST_PAGE_ALIGN(end); 561 562 /* 563 * Test if requested memory area fits target address space 564 * It can fail only on 64-bit host with 32-bit target. 565 * On any other target/host host mmap() handles this error correctly. 566 */ 567#if TARGET_ABI_BITS == 32 && HOST_LONG_BITS == 64 568 if ((unsigned long)start + len - 1 > (abi_ulong) -1) { 569 errno = EINVAL; 570 goto fail; 571 } 572#endif 573 574 /* 575 * worst case: we cannot map the file because the offset is not 576 * aligned, so we read it 577 */ 578 if (!(flags & MAP_ANON) && 579 (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) { 580 /* 581 * msync() won't work here, so we return an error if write is 582 * possible while it is a shared mapping 583 */ 584 if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED && 585 (prot & PROT_WRITE)) { 586 errno = EINVAL; 587 goto fail; 588 } 589 retaddr = target_mmap(start, len, prot | PROT_WRITE, 590 MAP_FIXED | MAP_PRIVATE | MAP_ANON, 591 -1, 0); 592 if (retaddr == -1) 593 goto fail; 594 pread(fd, g2h_untagged(start), len, offset); 595 if (!(prot & PROT_WRITE)) { 596 ret = target_mprotect(start, len, prot); 597 if (ret != 0) { 598 start = ret; 599 goto the_end; 600 } 601 } 602 goto the_end; 603 } 604 605 /* handle the start of the mapping */ 606 if (start > real_start) { 607 if (real_end == real_start + qemu_host_page_size) { 608 /* one single host page */ 609 ret = mmap_frag(real_start, start, end, 610 prot, flags, fd, offset); 611 if (ret == -1) 612 goto fail; 613 goto the_end1; 614 } 615 ret = mmap_frag(real_start, start, real_start + qemu_host_page_size, 616 prot, flags, fd, offset); 617 if (ret == -1) 618 goto fail; 619 real_start += qemu_host_page_size; 620 } 621 /* handle the end of the mapping */ 622 if (end < real_end) { 623 ret = mmap_frag(real_end - qemu_host_page_size, 624 real_end - qemu_host_page_size, end, 625 prot, flags, fd, 626 offset + real_end - qemu_host_page_size - start); 627 if (ret == -1) 628 goto fail; 629 real_end -= qemu_host_page_size; 630 } 631 632 /* map the middle (easier) */ 633 if (real_start < real_end) { 634 void *p; 635 unsigned long offset1; 636 if (flags & MAP_ANON) 637 offset1 = 0; 638 else 639 offset1 = offset + real_start - start; 640 p = mmap(g2h_untagged(real_start), real_end - real_start, 641 prot, flags, fd, offset1); 642 if (p == MAP_FAILED) 643 goto fail; 644 } 645 } 646 the_end1: 647 page_set_flags(start, start + len, prot | PAGE_VALID); 648 the_end: 649#ifdef DEBUG_MMAP 650 printf("ret=0x" TARGET_ABI_FMT_lx "\n", start); 651 page_dump(stdout); 652 printf("\n"); 653#endif 654 tb_invalidate_phys_range(start, start + len); 655 mmap_unlock(); 656 return start; 657fail: 658 mmap_unlock(); 659 return -1; 660} 661 662static void mmap_reserve(abi_ulong start, abi_ulong size) 663{ 664 abi_ulong real_start; 665 abi_ulong real_end; 666 abi_ulong addr; 667 abi_ulong end; 668 int prot; 669 670 real_start = start & qemu_host_page_mask; 671 real_end = HOST_PAGE_ALIGN(start + size); 672 end = start + size; 673 if (start > real_start) { 674 /* handle host page containing start */ 675 prot = 0; 676 for (addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) { 677 prot |= page_get_flags(addr); 678 } 679 if (real_end == real_start + qemu_host_page_size) { 680 for (addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { 681 prot |= page_get_flags(addr); 682 } 683 end = real_end; 684 } 685 if (prot != 0) { 686 real_start += qemu_host_page_size; 687 } 688 } 689 if (end < real_end) { 690 prot = 0; 691 for (addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { 692 prot |= page_get_flags(addr); 693 } 694 if (prot != 0) { 695 real_end -= qemu_host_page_size; 696 } 697 } 698 if (real_start != real_end) { 699 mmap(g2h_untagged(real_start), real_end - real_start, PROT_NONE, 700 MAP_FIXED | MAP_ANONYMOUS | MAP_PRIVATE, 701 -1, 0); 702 } 703} 704 705int target_munmap(abi_ulong start, abi_ulong len) 706{ 707 abi_ulong end, real_start, real_end, addr; 708 int prot, ret; 709 710#ifdef DEBUG_MMAP 711 printf("munmap: start=0x" TARGET_ABI_FMT_lx " len=0x" 712 TARGET_ABI_FMT_lx "\n", 713 start, len); 714#endif 715 if (start & ~TARGET_PAGE_MASK) 716 return -EINVAL; 717 len = TARGET_PAGE_ALIGN(len); 718 if (len == 0) 719 return -EINVAL; 720 mmap_lock(); 721 end = start + len; 722 real_start = start & qemu_host_page_mask; 723 real_end = HOST_PAGE_ALIGN(end); 724 725 if (start > real_start) { 726 /* handle host page containing start */ 727 prot = 0; 728 for (addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) { 729 prot |= page_get_flags(addr); 730 } 731 if (real_end == real_start + qemu_host_page_size) { 732 for (addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { 733 prot |= page_get_flags(addr); 734 } 735 end = real_end; 736 } 737 if (prot != 0) 738 real_start += qemu_host_page_size; 739 } 740 if (end < real_end) { 741 prot = 0; 742 for (addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) { 743 prot |= page_get_flags(addr); 744 } 745 if (prot != 0) 746 real_end -= qemu_host_page_size; 747 } 748 749 ret = 0; 750 /* unmap what we can */ 751 if (real_start < real_end) { 752 if (reserved_va) { 753 mmap_reserve(real_start, real_end - real_start); 754 } else { 755 ret = munmap(g2h_untagged(real_start), real_end - real_start); 756 } 757 } 758 759 if (ret == 0) { 760 page_set_flags(start, start + len, 0); 761 tb_invalidate_phys_range(start, start + len); 762 } 763 mmap_unlock(); 764 return ret; 765} 766 767int target_msync(abi_ulong start, abi_ulong len, int flags) 768{ 769 abi_ulong end; 770 771 if (start & ~TARGET_PAGE_MASK) 772 return -EINVAL; 773 len = TARGET_PAGE_ALIGN(len); 774 end = start + len; 775 if (end < start) 776 return -EINVAL; 777 if (end == start) 778 return 0; 779 780 start &= qemu_host_page_mask; 781 return msync(g2h_untagged(start), end - start, flags); 782}