mem_map.cc revision 5c42c29b89286e5efa4a4613132b09051ce5945b
1/* 2 * Copyright (C) 2008 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "mem_map.h" 18 19#include <backtrace/BacktraceMap.h> 20#include <inttypes.h> 21 22#include <memory> 23#include <sstream> 24 25// See CreateStartPos below. 26#ifdef __BIONIC__ 27#include <sys/auxv.h> 28#endif 29 30#include "base/stringprintf.h" 31 32#pragma GCC diagnostic push 33#pragma GCC diagnostic ignored "-Wshadow" 34#include "ScopedFd.h" 35#pragma GCC diagnostic pop 36 37#include "thread-inl.h" 38#include "utils.h" 39 40#define USE_ASHMEM 1 41 42#ifdef USE_ASHMEM 43#include <cutils/ashmem.h> 44#ifndef ANDROID_OS 45#include <sys/resource.h> 46#endif 47#endif 48 49#ifndef MAP_ANONYMOUS 50#define MAP_ANONYMOUS MAP_ANON 51#endif 52 53namespace art { 54 55static std::ostream& operator<<( 56 std::ostream& os, 57 std::pair<BacktraceMap::const_iterator, BacktraceMap::const_iterator> iters) { 58 for (BacktraceMap::const_iterator it = iters.first; it != iters.second; ++it) { 59 os << StringPrintf("0x%08x-0x%08x %c%c%c %s\n", 60 static_cast<uint32_t>(it->start), 61 static_cast<uint32_t>(it->end), 62 (it->flags & PROT_READ) ? 'r' : '-', 63 (it->flags & PROT_WRITE) ? 'w' : '-', 64 (it->flags & PROT_EXEC) ? 'x' : '-', it->name.c_str()); 65 } 66 return os; 67} 68 69std::ostream& operator<<(std::ostream& os, const MemMap::Maps& mem_maps) { 70 os << "MemMap:" << std::endl; 71 for (auto it = mem_maps.begin(); it != mem_maps.end(); ++it) { 72 void* base = it->first; 73 MemMap* map = it->second; 74 CHECK_EQ(base, map->BaseBegin()); 75 os << *map << std::endl; 76 } 77 return os; 78} 79 80MemMap::Maps* MemMap::maps_ = nullptr; 81 82#if USE_ART_LOW_4G_ALLOCATOR 83// Handling mem_map in 32b address range for 64b architectures that do not support MAP_32BIT. 84 85// The regular start of memory allocations. The first 64KB is protected by SELinux. 86static constexpr uintptr_t LOW_MEM_START = 64 * KB; 87 88// Generate random starting position. 89// To not interfere with image position, take the image's address and only place it below. Current 90// formula (sketch): 91// 92// ART_BASE_ADDR = 0001XXXXXXXXXXXXXXX 93// ---------------------------------------- 94// = 0000111111111111111 95// & ~(kPageSize - 1) =~0000000000000001111 96// ---------------------------------------- 97// mask = 0000111111111110000 98// & random data = YYYYYYYYYYYYYYYYYYY 99// ----------------------------------- 100// tmp = 0000YYYYYYYYYYY0000 101// + LOW_MEM_START = 0000000000001000000 102// -------------------------------------- 103// start 104// 105// getauxval as an entropy source is exposed in Bionic, but not in glibc before 2.16. When we 106// do not have Bionic, simply start with LOW_MEM_START. 107 108// Function is standalone so it can be tested somewhat in mem_map_test.cc. 109#ifdef __BIONIC__ 110uintptr_t CreateStartPos(uint64_t input) { 111 CHECK_NE(0, ART_BASE_ADDRESS); 112 113 // Start with all bits below highest bit in ART_BASE_ADDRESS. 114 constexpr size_t leading_zeros = CLZ(static_cast<uint32_t>(ART_BASE_ADDRESS)); 115 constexpr uintptr_t mask_ones = (1 << (31 - leading_zeros)) - 1; 116 117 // Lowest (usually 12) bits are not used, as aligned by page size. 118 constexpr uintptr_t mask = mask_ones & ~(kPageSize - 1); 119 120 // Mask input data. 121 return (input & mask) + LOW_MEM_START; 122} 123#endif 124 125static uintptr_t GenerateNextMemPos() { 126#ifdef __BIONIC__ 127 uint8_t* random_data = reinterpret_cast<uint8_t*>(getauxval(AT_RANDOM)); 128 // The lower 8B are taken for the stack guard. Use the upper 8B (with mask). 129 return CreateStartPos(*reinterpret_cast<uintptr_t*>(random_data + 8)); 130#else 131 // No auxv on host, see above. 132 return LOW_MEM_START; 133#endif 134} 135 136// Initialize linear scan to random position. 137uintptr_t MemMap::next_mem_pos_ = GenerateNextMemPos(); 138#endif 139 140// Return true if the address range is contained in a single /proc/self/map entry. 141static bool ContainedWithinExistingMap(uint8_t* ptr, size_t size, 142 std::string* error_msg) { 143 uintptr_t begin = reinterpret_cast<uintptr_t>(ptr); 144 uintptr_t end = begin + size; 145 std::unique_ptr<BacktraceMap> map(BacktraceMap::Create(getpid(), true)); 146 if (map.get() == nullptr) { 147 *error_msg = StringPrintf("Failed to build process map"); 148 return false; 149 } 150 for (BacktraceMap::const_iterator it = map->begin(); it != map->end(); ++it) { 151 if ((begin >= it->start && begin < it->end) // start of new within old 152 && (end > it->start && end <= it->end)) { // end of new within old 153 return true; 154 } 155 } 156 PrintFileToLog("/proc/self/maps", LogSeverity::WARNING); 157 *error_msg = StringPrintf("Requested region 0x%08" PRIxPTR "-0x%08" PRIxPTR " does not overlap " 158 "any existing map. See process maps in the log.", begin, end); 159 return false; 160} 161 162// Return true if the address range does not conflict with any /proc/self/maps entry. 163static bool CheckNonOverlapping(uintptr_t begin, 164 uintptr_t end, 165 std::string* error_msg) { 166 std::unique_ptr<BacktraceMap> map(BacktraceMap::Create(getpid(), true)); 167 if (map.get() == nullptr) { 168 *error_msg = StringPrintf("Failed to build process map"); 169 return false; 170 } 171 for (BacktraceMap::const_iterator it = map->begin(); it != map->end(); ++it) { 172 if ((begin >= it->start && begin < it->end) // start of new within old 173 || (end > it->start && end < it->end) // end of new within old 174 || (begin <= it->start && end > it->end)) { // start/end of new includes all of old 175 std::ostringstream map_info; 176 map_info << std::make_pair(it, map->end()); 177 *error_msg = StringPrintf("Requested region 0x%08" PRIxPTR "-0x%08" PRIxPTR " overlaps with " 178 "existing map 0x%08" PRIxPTR "-0x%08" PRIxPTR " (%s)\n%s", 179 begin, end, 180 static_cast<uintptr_t>(it->start), static_cast<uintptr_t>(it->end), 181 it->name.c_str(), 182 map_info.str().c_str()); 183 return false; 184 } 185 } 186 return true; 187} 188 189// CheckMapRequest to validate a non-MAP_FAILED mmap result based on 190// the expected value, calling munmap if validation fails, giving the 191// reason in error_msg. 192// 193// If the expected_ptr is nullptr, nothing is checked beyond the fact 194// that the actual_ptr is not MAP_FAILED. However, if expected_ptr is 195// non-null, we check that pointer is the actual_ptr == expected_ptr, 196// and if not, report in error_msg what the conflict mapping was if 197// found, or a generic error in other cases. 198static bool CheckMapRequest(uint8_t* expected_ptr, void* actual_ptr, size_t byte_count, 199 std::string* error_msg) { 200 // Handled first by caller for more specific error messages. 201 CHECK(actual_ptr != MAP_FAILED); 202 203 if (expected_ptr == nullptr) { 204 return true; 205 } 206 207 uintptr_t actual = reinterpret_cast<uintptr_t>(actual_ptr); 208 uintptr_t expected = reinterpret_cast<uintptr_t>(expected_ptr); 209 uintptr_t limit = expected + byte_count; 210 211 if (expected_ptr == actual_ptr) { 212 return true; 213 } 214 215 // We asked for an address but didn't get what we wanted, all paths below here should fail. 216 int result = munmap(actual_ptr, byte_count); 217 if (result == -1) { 218 PLOG(WARNING) << StringPrintf("munmap(%p, %zd) failed", actual_ptr, byte_count); 219 } 220 221 // We call this here so that we can try and generate a full error 222 // message with the overlapping mapping. There's no guarantee that 223 // that there will be an overlap though, since 224 // - The kernel is not *required* to honour expected_ptr unless MAP_FIXED is 225 // true, even if there is no overlap 226 // - There might have been an overlap at the point of mmap, but the 227 // overlapping region has since been unmapped. 228 std::string error_detail; 229 CheckNonOverlapping(expected, limit, &error_detail); 230 231 std::ostringstream os; 232 os << StringPrintf("Failed to mmap at expected address, mapped at " 233 "0x%08" PRIxPTR " instead of 0x%08" PRIxPTR, 234 actual, expected); 235 if (!error_detail.empty()) { 236 os << " : " << error_detail; 237 } 238 239 *error_msg = os.str(); 240 return false; 241} 242 243MemMap* MemMap::MapAnonymous(const char* name, uint8_t* expected_ptr, size_t byte_count, int prot, 244 bool low_4gb, bool reuse, std::string* error_msg) { 245#ifndef __LP64__ 246 UNUSED(low_4gb); 247#endif 248 if (byte_count == 0) { 249 return new MemMap(name, nullptr, 0, nullptr, 0, prot, false); 250 } 251 size_t page_aligned_byte_count = RoundUp(byte_count, kPageSize); 252 253 int flags = MAP_PRIVATE | MAP_ANONYMOUS; 254 if (reuse) { 255 // reuse means it is okay that it overlaps an existing page mapping. 256 // Only use this if you actually made the page reservation yourself. 257 CHECK(expected_ptr != nullptr); 258 259 DCHECK(ContainedWithinExistingMap(expected_ptr, byte_count, error_msg)) << error_msg; 260 flags |= MAP_FIXED; 261 } 262 263 ScopedFd fd(-1); 264 265#ifdef USE_ASHMEM 266#ifdef HAVE_ANDROID_OS 267 const bool use_ashmem = true; 268#else 269 // When not on Android ashmem is faked using files in /tmp. Ensure that such files won't 270 // fail due to ulimit restrictions. If they will then use a regular mmap. 271 struct rlimit rlimit_fsize; 272 CHECK_EQ(getrlimit(RLIMIT_FSIZE, &rlimit_fsize), 0); 273 const bool use_ashmem = (rlimit_fsize.rlim_cur == RLIM_INFINITY) || 274 (page_aligned_byte_count < rlimit_fsize.rlim_cur); 275#endif 276 if (use_ashmem) { 277 // android_os_Debug.cpp read_mapinfo assumes all ashmem regions associated with the VM are 278 // prefixed "dalvik-". 279 std::string debug_friendly_name("dalvik-"); 280 debug_friendly_name += name; 281 fd.reset(ashmem_create_region(debug_friendly_name.c_str(), page_aligned_byte_count)); 282 if (fd.get() == -1) { 283 *error_msg = StringPrintf("ashmem_create_region failed for '%s': %s", name, strerror(errno)); 284 return nullptr; 285 } 286 flags &= ~MAP_ANONYMOUS; 287 } 288#endif 289 290 // We need to store and potentially set an error number for pretty printing of errors 291 int saved_errno = 0; 292 293#ifdef __LP64__ 294 // When requesting low_4g memory and having an expectation, the requested range should fit into 295 // 4GB. 296 if (low_4gb && ( 297 // Start out of bounds. 298 (reinterpret_cast<uintptr_t>(expected_ptr) >> 32) != 0 || 299 // End out of bounds. For simplicity, this will fail for the last page of memory. 300 (reinterpret_cast<uintptr_t>(expected_ptr + page_aligned_byte_count) >> 32) != 0)) { 301 *error_msg = StringPrintf("The requested address space (%p, %p) cannot fit in low_4gb", 302 expected_ptr, expected_ptr + page_aligned_byte_count); 303 return nullptr; 304 } 305#endif 306 307 // TODO: 308 // A page allocator would be a useful abstraction here, as 309 // 1) It is doubtful that MAP_32BIT on x86_64 is doing the right job for us 310 // 2) The linear scheme, even with simple saving of the last known position, is very crude 311#if USE_ART_LOW_4G_ALLOCATOR 312 // MAP_32BIT only available on x86_64. 313 void* actual = MAP_FAILED; 314 if (low_4gb && expected_ptr == nullptr) { 315 bool first_run = true; 316 317 for (uintptr_t ptr = next_mem_pos_; ptr < 4 * GB; ptr += kPageSize) { 318 if (4U * GB - ptr < page_aligned_byte_count) { 319 // Not enough memory until 4GB. 320 if (first_run) { 321 // Try another time from the bottom; 322 ptr = LOW_MEM_START - kPageSize; 323 first_run = false; 324 continue; 325 } else { 326 // Second try failed. 327 break; 328 } 329 } 330 331 uintptr_t tail_ptr; 332 333 // Check pages are free. 334 bool safe = true; 335 for (tail_ptr = ptr; tail_ptr < ptr + page_aligned_byte_count; tail_ptr += kPageSize) { 336 if (msync(reinterpret_cast<void*>(tail_ptr), kPageSize, 0) == 0) { 337 safe = false; 338 break; 339 } else { 340 DCHECK_EQ(errno, ENOMEM); 341 } 342 } 343 344 next_mem_pos_ = tail_ptr; // update early, as we break out when we found and mapped a region 345 346 if (safe == true) { 347 actual = mmap(reinterpret_cast<void*>(ptr), page_aligned_byte_count, prot, flags, fd.get(), 348 0); 349 if (actual != MAP_FAILED) { 350 // Since we didn't use MAP_FIXED the kernel may have mapped it somewhere not in the low 351 // 4GB. If this is the case, unmap and retry. 352 if (reinterpret_cast<uintptr_t>(actual) + page_aligned_byte_count < 4 * GB) { 353 break; 354 } else { 355 munmap(actual, page_aligned_byte_count); 356 actual = MAP_FAILED; 357 } 358 } 359 } else { 360 // Skip over last page. 361 ptr = tail_ptr; 362 } 363 } 364 365 if (actual == MAP_FAILED) { 366 LOG(ERROR) << "Could not find contiguous low-memory space."; 367 saved_errno = ENOMEM; 368 } 369 } else { 370 actual = mmap(expected_ptr, page_aligned_byte_count, prot, flags, fd.get(), 0); 371 saved_errno = errno; 372 } 373 374#else 375#if defined(__LP64__) 376 if (low_4gb && expected_ptr == nullptr) { 377 flags |= MAP_32BIT; 378 } 379#endif 380 381 void* actual = mmap(expected_ptr, page_aligned_byte_count, prot, flags, fd.get(), 0); 382 saved_errno = errno; 383#endif 384 385 if (actual == MAP_FAILED) { 386 PrintFileToLog("/proc/self/maps", LogSeverity::WARNING); 387 388 *error_msg = StringPrintf("Failed anonymous mmap(%p, %zd, 0x%x, 0x%x, %d, 0): %s. See process " 389 "maps in the log.", expected_ptr, page_aligned_byte_count, prot, 390 flags, fd.get(), strerror(saved_errno)); 391 return nullptr; 392 } 393 std::ostringstream check_map_request_error_msg; 394 if (!CheckMapRequest(expected_ptr, actual, page_aligned_byte_count, error_msg)) { 395 return nullptr; 396 } 397 return new MemMap(name, reinterpret_cast<uint8_t*>(actual), byte_count, actual, 398 page_aligned_byte_count, prot, false); 399} 400 401MemMap* MemMap::MapFileAtAddress(uint8_t* expected_ptr, size_t byte_count, int prot, int flags, int fd, 402 off_t start, bool reuse, const char* filename, 403 std::string* error_msg) { 404 CHECK_NE(0, prot); 405 CHECK_NE(0, flags & (MAP_SHARED | MAP_PRIVATE)); 406 407 // Note that we do not allow MAP_FIXED unless reuse == true, i.e we 408 // expect his mapping to be contained within an existing map. 409 if (reuse) { 410 // reuse means it is okay that it overlaps an existing page mapping. 411 // Only use this if you actually made the page reservation yourself. 412 CHECK(expected_ptr != nullptr); 413 414 DCHECK(ContainedWithinExistingMap(expected_ptr, byte_count, error_msg)) << error_msg; 415 flags |= MAP_FIXED; 416 } else { 417 CHECK_EQ(0, flags & MAP_FIXED); 418 // Don't bother checking for an overlapping region here. We'll 419 // check this if required after the fact inside CheckMapRequest. 420 } 421 422 if (byte_count == 0) { 423 return new MemMap(filename, nullptr, 0, nullptr, 0, prot, false); 424 } 425 // Adjust 'offset' to be page-aligned as required by mmap. 426 int page_offset = start % kPageSize; 427 off_t page_aligned_offset = start - page_offset; 428 // Adjust 'byte_count' to be page-aligned as we will map this anyway. 429 size_t page_aligned_byte_count = RoundUp(byte_count + page_offset, kPageSize); 430 // The 'expected_ptr' is modified (if specified, ie non-null) to be page aligned to the file but 431 // not necessarily to virtual memory. mmap will page align 'expected' for us. 432 uint8_t* page_aligned_expected = (expected_ptr == nullptr) ? nullptr : (expected_ptr - page_offset); 433 434 uint8_t* actual = reinterpret_cast<uint8_t*>(mmap(page_aligned_expected, 435 page_aligned_byte_count, 436 prot, 437 flags, 438 fd, 439 page_aligned_offset)); 440 if (actual == MAP_FAILED) { 441 auto saved_errno = errno; 442 443 PrintFileToLog("/proc/self/maps", LogSeverity::WARNING); 444 445 *error_msg = StringPrintf("mmap(%p, %zd, 0x%x, 0x%x, %d, %" PRId64 446 ") of file '%s' failed: %s. See process maps in the log.", 447 page_aligned_expected, page_aligned_byte_count, prot, flags, fd, 448 static_cast<int64_t>(page_aligned_offset), filename, 449 strerror(saved_errno)); 450 return nullptr; 451 } 452 std::ostringstream check_map_request_error_msg; 453 if (!CheckMapRequest(expected_ptr, actual, page_aligned_byte_count, error_msg)) { 454 return nullptr; 455 } 456 return new MemMap(filename, actual + page_offset, byte_count, actual, page_aligned_byte_count, 457 prot, reuse); 458} 459 460MemMap::~MemMap() { 461 if (base_begin_ == nullptr && base_size_ == 0) { 462 return; 463 } 464 if (!reuse_) { 465 int result = munmap(base_begin_, base_size_); 466 if (result == -1) { 467 PLOG(FATAL) << "munmap failed"; 468 } 469 } 470 471 // Remove it from maps_. 472 MutexLock mu(Thread::Current(), *Locks::mem_maps_lock_); 473 bool found = false; 474 DCHECK(maps_ != nullptr); 475 for (auto it = maps_->lower_bound(base_begin_), end = maps_->end(); 476 it != end && it->first == base_begin_; ++it) { 477 if (it->second == this) { 478 found = true; 479 maps_->erase(it); 480 break; 481 } 482 } 483 CHECK(found) << "MemMap not found"; 484} 485 486MemMap::MemMap(const std::string& name, uint8_t* begin, size_t size, void* base_begin, 487 size_t base_size, int prot, bool reuse) 488 : name_(name), begin_(begin), size_(size), base_begin_(base_begin), base_size_(base_size), 489 prot_(prot), reuse_(reuse) { 490 if (size_ == 0) { 491 CHECK(begin_ == nullptr); 492 CHECK(base_begin_ == nullptr); 493 CHECK_EQ(base_size_, 0U); 494 } else { 495 CHECK(begin_ != nullptr); 496 CHECK(base_begin_ != nullptr); 497 CHECK_NE(base_size_, 0U); 498 499 // Add it to maps_. 500 MutexLock mu(Thread::Current(), *Locks::mem_maps_lock_); 501 DCHECK(maps_ != nullptr); 502 maps_->insert(std::make_pair(base_begin_, this)); 503 } 504} 505 506MemMap* MemMap::RemapAtEnd(uint8_t* new_end, const char* tail_name, int tail_prot, 507 std::string* error_msg) { 508 DCHECK_GE(new_end, Begin()); 509 DCHECK_LE(new_end, End()); 510 DCHECK_LE(begin_ + size_, reinterpret_cast<uint8_t*>(base_begin_) + base_size_); 511 DCHECK(IsAligned<kPageSize>(begin_)); 512 DCHECK(IsAligned<kPageSize>(base_begin_)); 513 DCHECK(IsAligned<kPageSize>(reinterpret_cast<uint8_t*>(base_begin_) + base_size_)); 514 DCHECK(IsAligned<kPageSize>(new_end)); 515 uint8_t* old_end = begin_ + size_; 516 uint8_t* old_base_end = reinterpret_cast<uint8_t*>(base_begin_) + base_size_; 517 uint8_t* new_base_end = new_end; 518 DCHECK_LE(new_base_end, old_base_end); 519 if (new_base_end == old_base_end) { 520 return new MemMap(tail_name, nullptr, 0, nullptr, 0, tail_prot, false); 521 } 522 size_ = new_end - reinterpret_cast<uint8_t*>(begin_); 523 base_size_ = new_base_end - reinterpret_cast<uint8_t*>(base_begin_); 524 DCHECK_LE(begin_ + size_, reinterpret_cast<uint8_t*>(base_begin_) + base_size_); 525 size_t tail_size = old_end - new_end; 526 uint8_t* tail_base_begin = new_base_end; 527 size_t tail_base_size = old_base_end - new_base_end; 528 DCHECK_EQ(tail_base_begin + tail_base_size, old_base_end); 529 DCHECK(IsAligned<kPageSize>(tail_base_size)); 530 531#ifdef USE_ASHMEM 532 // android_os_Debug.cpp read_mapinfo assumes all ashmem regions associated with the VM are 533 // prefixed "dalvik-". 534 std::string debug_friendly_name("dalvik-"); 535 debug_friendly_name += tail_name; 536 ScopedFd fd(ashmem_create_region(debug_friendly_name.c_str(), tail_base_size)); 537 int flags = MAP_PRIVATE | MAP_FIXED; 538 if (fd.get() == -1) { 539 *error_msg = StringPrintf("ashmem_create_region failed for '%s': %s", 540 tail_name, strerror(errno)); 541 return nullptr; 542 } 543#else 544 ScopedFd fd(-1); 545 int flags = MAP_PRIVATE | MAP_ANONYMOUS; 546#endif 547 548 // Unmap/map the tail region. 549 int result = munmap(tail_base_begin, tail_base_size); 550 if (result == -1) { 551 PrintFileToLog("/proc/self/maps", LogSeverity::WARNING); 552 *error_msg = StringPrintf("munmap(%p, %zd) failed for '%s'. See process maps in the log.", 553 tail_base_begin, tail_base_size, name_.c_str()); 554 return nullptr; 555 } 556 // Don't cause memory allocation between the munmap and the mmap 557 // calls. Otherwise, libc (or something else) might take this memory 558 // region. Note this isn't perfect as there's no way to prevent 559 // other threads to try to take this memory region here. 560 uint8_t* actual = reinterpret_cast<uint8_t*>(mmap(tail_base_begin, tail_base_size, tail_prot, 561 flags, fd.get(), 0)); 562 if (actual == MAP_FAILED) { 563 PrintFileToLog("/proc/self/maps", LogSeverity::WARNING); 564 *error_msg = StringPrintf("anonymous mmap(%p, %zd, 0x%x, 0x%x, %d, 0) failed. See process " 565 "maps in the log.", tail_base_begin, tail_base_size, tail_prot, flags, 566 fd.get()); 567 return nullptr; 568 } 569 return new MemMap(tail_name, actual, tail_size, actual, tail_base_size, tail_prot, false); 570} 571 572void MemMap::MadviseDontNeedAndZero() { 573 if (base_begin_ != nullptr || base_size_ != 0) { 574 if (!kMadviseZeroes) { 575 memset(base_begin_, 0, base_size_); 576 } 577 int result = madvise(base_begin_, base_size_, MADV_DONTNEED); 578 if (result == -1) { 579 PLOG(WARNING) << "madvise failed"; 580 } 581 } 582} 583 584bool MemMap::Protect(int prot) { 585 if (base_begin_ == nullptr && base_size_ == 0) { 586 prot_ = prot; 587 return true; 588 } 589 590 if (mprotect(base_begin_, base_size_, prot) == 0) { 591 prot_ = prot; 592 return true; 593 } 594 595 PLOG(ERROR) << "mprotect(" << reinterpret_cast<void*>(base_begin_) << ", " << base_size_ << ", " 596 << prot << ") failed"; 597 return false; 598} 599 600bool MemMap::CheckNoGaps(MemMap* begin_map, MemMap* end_map) { 601 MutexLock mu(Thread::Current(), *Locks::mem_maps_lock_); 602 CHECK(begin_map != nullptr); 603 CHECK(end_map != nullptr); 604 CHECK(HasMemMap(begin_map)); 605 CHECK(HasMemMap(end_map)); 606 CHECK_LE(begin_map->BaseBegin(), end_map->BaseBegin()); 607 MemMap* map = begin_map; 608 while (map->BaseBegin() != end_map->BaseBegin()) { 609 MemMap* next_map = GetLargestMemMapAt(map->BaseEnd()); 610 if (next_map == nullptr) { 611 // Found a gap. 612 return false; 613 } 614 map = next_map; 615 } 616 return true; 617} 618 619void MemMap::DumpMaps(std::ostream& os) { 620 MutexLock mu(Thread::Current(), *Locks::mem_maps_lock_); 621 DumpMapsLocked(os); 622} 623 624void MemMap::DumpMapsLocked(std::ostream& os) { 625 os << maps_; 626} 627 628bool MemMap::HasMemMap(MemMap* map) { 629 void* base_begin = map->BaseBegin(); 630 for (auto it = maps_->lower_bound(base_begin), end = maps_->end(); 631 it != end && it->first == base_begin; ++it) { 632 if (it->second == map) { 633 return true; 634 } 635 } 636 return false; 637} 638 639MemMap* MemMap::GetLargestMemMapAt(void* address) { 640 size_t largest_size = 0; 641 MemMap* largest_map = nullptr; 642 DCHECK(maps_ != nullptr); 643 for (auto it = maps_->lower_bound(address), end = maps_->end(); 644 it != end && it->first == address; ++it) { 645 MemMap* map = it->second; 646 CHECK(map != nullptr); 647 if (largest_size < map->BaseSize()) { 648 largest_size = map->BaseSize(); 649 largest_map = map; 650 } 651 } 652 return largest_map; 653} 654 655void MemMap::Init() { 656 MutexLock mu(Thread::Current(), *Locks::mem_maps_lock_); 657 if (maps_ == nullptr) { 658 // dex2oat calls MemMap::Init twice since its needed before the runtime is created. 659 maps_ = new Maps; 660 } 661} 662 663void MemMap::Shutdown() { 664 MutexLock mu(Thread::Current(), *Locks::mem_maps_lock_); 665 delete maps_; 666 maps_ = nullptr; 667} 668 669void MemMap::SetSize(size_t new_size) { 670 if (new_size == base_size_) { 671 return; 672 } 673 CHECK_ALIGNED(new_size, kPageSize); 674 CHECK_EQ(base_size_, size_) << "Unsupported"; 675 CHECK_LE(new_size, base_size_); 676 CHECK_EQ(munmap(reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(BaseBegin()) + new_size), 677 base_size_ - new_size), 0) << new_size << " " << base_size_; 678 base_size_ = new_size; 679 size_ = new_size; 680} 681 682std::ostream& operator<<(std::ostream& os, const MemMap& mem_map) { 683 os << StringPrintf("[MemMap: %p-%p prot=0x%x %s]", 684 mem_map.BaseBegin(), mem_map.BaseEnd(), mem_map.GetProtect(), 685 mem_map.GetName().c_str()); 686 return os; 687} 688 689} // namespace art 690