| /* |
| * Copyright (C) 2008 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "mem_map.h" |
| |
| #include "base/memory_tool.h" |
| #include <backtrace/BacktraceMap.h> |
| #include <inttypes.h> |
| #include <stdlib.h> |
| |
| #include <memory> |
| #include <sstream> |
| |
| #include "base/stringprintf.h" |
| |
| #pragma GCC diagnostic push |
| #pragma GCC diagnostic ignored "-Wshadow" |
| #include "ScopedFd.h" |
| #pragma GCC diagnostic pop |
| |
| #include "thread-inl.h" |
| #include "utils.h" |
| |
| #include <cutils/ashmem.h> |
| |
| #ifndef ANDROID_OS |
| #include <sys/resource.h> |
| #endif |
| |
| #ifndef MAP_ANONYMOUS |
| #define MAP_ANONYMOUS MAP_ANON |
| #endif |
| |
| namespace art { |
| |
| static std::ostream& operator<<( |
| std::ostream& os, |
| std::pair<BacktraceMap::const_iterator, BacktraceMap::const_iterator> iters) { |
| for (BacktraceMap::const_iterator it = iters.first; it != iters.second; ++it) { |
| os << StringPrintf("0x%08x-0x%08x %c%c%c %s\n", |
| static_cast<uint32_t>(it->start), |
| static_cast<uint32_t>(it->end), |
| (it->flags & PROT_READ) ? 'r' : '-', |
| (it->flags & PROT_WRITE) ? 'w' : '-', |
| (it->flags & PROT_EXEC) ? 'x' : '-', it->name.c_str()); |
| } |
| return os; |
| } |
| |
| std::ostream& operator<<(std::ostream& os, const MemMap::Maps& mem_maps) { |
| os << "MemMap:" << std::endl; |
| for (auto it = mem_maps.begin(); it != mem_maps.end(); ++it) { |
| void* base = it->first; |
| MemMap* map = it->second; |
| CHECK_EQ(base, map->BaseBegin()); |
| os << *map << std::endl; |
| } |
| return os; |
| } |
| |
| MemMap::Maps* MemMap::maps_ = nullptr; |
| |
| #if USE_ART_LOW_4G_ALLOCATOR |
| // Handling mem_map in 32b address range for 64b architectures that do not support MAP_32BIT. |
| |
| // The regular start of memory allocations. The first 64KB is protected by SELinux. |
| static constexpr uintptr_t LOW_MEM_START = 64 * KB; |
| |
| // Generate random starting position. |
| // To not interfere with image position, take the image's address and only place it below. Current |
| // formula (sketch): |
| // |
| // ART_BASE_ADDR = 0001XXXXXXXXXXXXXXX |
| // ---------------------------------------- |
| // = 0000111111111111111 |
| // & ~(kPageSize - 1) =~0000000000000001111 |
| // ---------------------------------------- |
| // mask = 0000111111111110000 |
| // & random data = YYYYYYYYYYYYYYYYYYY |
| // ----------------------------------- |
| // tmp = 0000YYYYYYYYYYY0000 |
| // + LOW_MEM_START = 0000000000001000000 |
| // -------------------------------------- |
| // start |
| // |
| // arc4random as an entropy source is exposed in Bionic, but not in glibc. When we |
| // do not have Bionic, simply start with LOW_MEM_START. |
| |
| // Function is standalone so it can be tested somewhat in mem_map_test.cc. |
| #ifdef __BIONIC__ |
| uintptr_t CreateStartPos(uint64_t input) { |
| CHECK_NE(0, ART_BASE_ADDRESS); |
| |
| // Start with all bits below highest bit in ART_BASE_ADDRESS. |
| constexpr size_t leading_zeros = CLZ(static_cast<uint32_t>(ART_BASE_ADDRESS)); |
| constexpr uintptr_t mask_ones = (1 << (31 - leading_zeros)) - 1; |
| |
| // Lowest (usually 12) bits are not used, as aligned by page size. |
| constexpr uintptr_t mask = mask_ones & ~(kPageSize - 1); |
| |
| // Mask input data. |
| return (input & mask) + LOW_MEM_START; |
| } |
| #endif |
| |
| static uintptr_t GenerateNextMemPos() { |
| #ifdef __BIONIC__ |
| uint64_t random_data; |
| arc4random_buf(&random_data, sizeof(random_data)); |
| return CreateStartPos(random_data); |
| #else |
| // No arc4random on host, see above. |
| return LOW_MEM_START; |
| #endif |
| } |
| |
| // Initialize linear scan to random position. |
| uintptr_t MemMap::next_mem_pos_ = GenerateNextMemPos(); |
| #endif |
| |
| // Return true if the address range is contained in a single memory map by either reading |
| // the maps_ variable or the /proc/self/map entry. |
| bool MemMap::ContainedWithinExistingMap(uint8_t* ptr, size_t size, std::string* error_msg) { |
| uintptr_t begin = reinterpret_cast<uintptr_t>(ptr); |
| uintptr_t end = begin + size; |
| |
| // There is a suspicion that BacktraceMap::Create is occasionally missing maps. TODO: Investigate |
| // further. |
| { |
| MutexLock mu(Thread::Current(), *Locks::mem_maps_lock_); |
| for (auto& pair : *maps_) { |
| MemMap* const map = pair.second; |
| if (begin >= reinterpret_cast<uintptr_t>(map->Begin()) && |
| end <= reinterpret_cast<uintptr_t>(map->End())) { |
| return true; |
| } |
| } |
| } |
| |
| std::unique_ptr<BacktraceMap> map(BacktraceMap::Create(getpid(), true)); |
| if (map == nullptr) { |
| if (error_msg != nullptr) { |
| *error_msg = StringPrintf("Failed to build process map"); |
| } |
| return false; |
| } |
| for (BacktraceMap::const_iterator it = map->begin(); it != map->end(); ++it) { |
| if ((begin >= it->start && begin < it->end) // start of new within old |
| && (end > it->start && end <= it->end)) { // end of new within old |
| return true; |
| } |
| } |
| if (error_msg != nullptr) { |
| PrintFileToLog("/proc/self/maps", LogSeverity::ERROR); |
| *error_msg = StringPrintf("Requested region 0x%08" PRIxPTR "-0x%08" PRIxPTR " does not overlap " |
| "any existing map. See process maps in the log.", begin, end); |
| } |
| return false; |
| } |
| |
| // Return true if the address range does not conflict with any /proc/self/maps entry. |
| static bool CheckNonOverlapping(uintptr_t begin, |
| uintptr_t end, |
| std::string* error_msg) { |
| std::unique_ptr<BacktraceMap> map(BacktraceMap::Create(getpid(), true)); |
| if (map.get() == nullptr) { |
| *error_msg = StringPrintf("Failed to build process map"); |
| return false; |
| } |
| for (BacktraceMap::const_iterator it = map->begin(); it != map->end(); ++it) { |
| if ((begin >= it->start && begin < it->end) // start of new within old |
| || (end > it->start && end < it->end) // end of new within old |
| || (begin <= it->start && end > it->end)) { // start/end of new includes all of old |
| std::ostringstream map_info; |
| map_info << std::make_pair(it, map->end()); |
| *error_msg = StringPrintf("Requested region 0x%08" PRIxPTR "-0x%08" PRIxPTR " overlaps with " |
| "existing map 0x%08" PRIxPTR "-0x%08" PRIxPTR " (%s)\n%s", |
| begin, end, |
| static_cast<uintptr_t>(it->start), static_cast<uintptr_t>(it->end), |
| it->name.c_str(), |
| map_info.str().c_str()); |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| // CheckMapRequest to validate a non-MAP_FAILED mmap result based on |
| // the expected value, calling munmap if validation fails, giving the |
| // reason in error_msg. |
| // |
| // If the expected_ptr is null, nothing is checked beyond the fact |
| // that the actual_ptr is not MAP_FAILED. However, if expected_ptr is |
| // non-null, we check that pointer is the actual_ptr == expected_ptr, |
| // and if not, report in error_msg what the conflict mapping was if |
| // found, or a generic error in other cases. |
| static bool CheckMapRequest(uint8_t* expected_ptr, void* actual_ptr, size_t byte_count, |
| std::string* error_msg) { |
| // Handled first by caller for more specific error messages. |
| CHECK(actual_ptr != MAP_FAILED); |
| |
| if (expected_ptr == nullptr) { |
| return true; |
| } |
| |
| uintptr_t actual = reinterpret_cast<uintptr_t>(actual_ptr); |
| uintptr_t expected = reinterpret_cast<uintptr_t>(expected_ptr); |
| uintptr_t limit = expected + byte_count; |
| |
| if (expected_ptr == actual_ptr) { |
| return true; |
| } |
| |
| // We asked for an address but didn't get what we wanted, all paths below here should fail. |
| int result = munmap(actual_ptr, byte_count); |
| if (result == -1) { |
| PLOG(WARNING) << StringPrintf("munmap(%p, %zd) failed", actual_ptr, byte_count); |
| } |
| |
| if (error_msg != nullptr) { |
| // We call this here so that we can try and generate a full error |
| // message with the overlapping mapping. There's no guarantee that |
| // that there will be an overlap though, since |
| // - The kernel is not *required* to honor expected_ptr unless MAP_FIXED is |
| // true, even if there is no overlap |
| // - There might have been an overlap at the point of mmap, but the |
| // overlapping region has since been unmapped. |
| std::string error_detail; |
| CheckNonOverlapping(expected, limit, &error_detail); |
| std::ostringstream os; |
| os << StringPrintf("Failed to mmap at expected address, mapped at " |
| "0x%08" PRIxPTR " instead of 0x%08" PRIxPTR, |
| actual, expected); |
| if (!error_detail.empty()) { |
| os << " : " << error_detail; |
| } |
| *error_msg = os.str(); |
| } |
| return false; |
| } |
| |
| #if USE_ART_LOW_4G_ALLOCATOR |
| static inline void* TryMemMapLow4GB(void* ptr, |
| size_t page_aligned_byte_count, |
| int prot, |
| int flags, |
| int fd, |
| off_t offset) { |
| void* actual = mmap(ptr, page_aligned_byte_count, prot, flags, fd, offset); |
| if (actual != MAP_FAILED) { |
| // Since we didn't use MAP_FIXED the kernel may have mapped it somewhere not in the low |
| // 4GB. If this is the case, unmap and retry. |
| if (reinterpret_cast<uintptr_t>(actual) + page_aligned_byte_count >= 4 * GB) { |
| munmap(actual, page_aligned_byte_count); |
| actual = MAP_FAILED; |
| } |
| } |
| return actual; |
| } |
| #endif |
| |
| MemMap* MemMap::MapAnonymous(const char* name, |
| uint8_t* expected_ptr, |
| size_t byte_count, |
| int prot, |
| bool low_4gb, |
| bool reuse, |
| std::string* error_msg, |
| bool use_ashmem) { |
| #ifndef __LP64__ |
| UNUSED(low_4gb); |
| #endif |
| if (byte_count == 0) { |
| return new MemMap(name, nullptr, 0, nullptr, 0, prot, false); |
| } |
| size_t page_aligned_byte_count = RoundUp(byte_count, kPageSize); |
| |
| int flags = MAP_PRIVATE | MAP_ANONYMOUS; |
| if (reuse) { |
| // reuse means it is okay that it overlaps an existing page mapping. |
| // Only use this if you actually made the page reservation yourself. |
| CHECK(expected_ptr != nullptr); |
| |
| DCHECK(ContainedWithinExistingMap(expected_ptr, byte_count, error_msg)) << *error_msg; |
| flags |= MAP_FIXED; |
| } |
| |
| ScopedFd fd(-1); |
| |
| if (use_ashmem) { |
| if (!kIsTargetBuild) { |
| // When not on Android ashmem is faked using files in /tmp. Ensure that such files won't |
| // fail due to ulimit restrictions. If they will then use a regular mmap. |
| struct rlimit rlimit_fsize; |
| CHECK_EQ(getrlimit(RLIMIT_FSIZE, &rlimit_fsize), 0); |
| use_ashmem = (rlimit_fsize.rlim_cur == RLIM_INFINITY) || |
| (page_aligned_byte_count < rlimit_fsize.rlim_cur); |
| } |
| } |
| |
| if (use_ashmem) { |
| // android_os_Debug.cpp read_mapinfo assumes all ashmem regions associated with the VM are |
| // prefixed "dalvik-". |
| std::string debug_friendly_name("dalvik-"); |
| debug_friendly_name += name; |
| fd.reset(ashmem_create_region(debug_friendly_name.c_str(), page_aligned_byte_count)); |
| if (fd.get() == -1) { |
| *error_msg = StringPrintf("ashmem_create_region failed for '%s': %s", name, strerror(errno)); |
| return nullptr; |
| } |
| flags &= ~MAP_ANONYMOUS; |
| } |
| |
| // We need to store and potentially set an error number for pretty printing of errors |
| int saved_errno = 0; |
| |
| void* actual = MapInternal(expected_ptr, |
| page_aligned_byte_count, |
| prot, |
| flags, |
| fd.get(), |
| 0, |
| low_4gb); |
| saved_errno = errno; |
| |
| if (actual == MAP_FAILED) { |
| if (error_msg != nullptr) { |
| PrintFileToLog("/proc/self/maps", LogSeverity::WARNING); |
| |
| *error_msg = StringPrintf("Failed anonymous mmap(%p, %zd, 0x%x, 0x%x, %d, 0): %s. " |
| "See process maps in the log.", |
| expected_ptr, |
| page_aligned_byte_count, |
| prot, |
| flags, |
| fd.get(), |
| strerror(saved_errno)); |
| } |
| return nullptr; |
| } |
| std::ostringstream check_map_request_error_msg; |
| if (!CheckMapRequest(expected_ptr, actual, page_aligned_byte_count, error_msg)) { |
| return nullptr; |
| } |
| return new MemMap(name, reinterpret_cast<uint8_t*>(actual), byte_count, actual, |
| page_aligned_byte_count, prot, reuse); |
| } |
| |
| MemMap* MemMap::MapDummy(const char* name, uint8_t* addr, size_t byte_count) { |
| if (byte_count == 0) { |
| return new MemMap(name, nullptr, 0, nullptr, 0, 0, false); |
| } |
| const size_t page_aligned_byte_count = RoundUp(byte_count, kPageSize); |
| return new MemMap(name, addr, byte_count, addr, page_aligned_byte_count, 0, true /* reuse */); |
| } |
| |
| MemMap* MemMap::MapFileAtAddress(uint8_t* expected_ptr, |
| size_t byte_count, |
| int prot, |
| int flags, |
| int fd, |
| off_t start, |
| bool low_4gb, |
| bool reuse, |
| const char* filename, |
| std::string* error_msg) { |
| CHECK_NE(0, prot); |
| CHECK_NE(0, flags & (MAP_SHARED | MAP_PRIVATE)); |
| |
| // Note that we do not allow MAP_FIXED unless reuse == true, i.e we |
| // expect his mapping to be contained within an existing map. |
| if (reuse) { |
| // reuse means it is okay that it overlaps an existing page mapping. |
| // Only use this if you actually made the page reservation yourself. |
| CHECK(expected_ptr != nullptr); |
| |
| DCHECK(ContainedWithinExistingMap(expected_ptr, byte_count, error_msg)) |
| << ((error_msg != nullptr) ? *error_msg : std::string()); |
| flags |= MAP_FIXED; |
| } else { |
| CHECK_EQ(0, flags & MAP_FIXED); |
| // Don't bother checking for an overlapping region here. We'll |
| // check this if required after the fact inside CheckMapRequest. |
| } |
| |
| if (byte_count == 0) { |
| return new MemMap(filename, nullptr, 0, nullptr, 0, prot, false); |
| } |
| // Adjust 'offset' to be page-aligned as required by mmap. |
| int page_offset = start % kPageSize; |
| off_t page_aligned_offset = start - page_offset; |
| // Adjust 'byte_count' to be page-aligned as we will map this anyway. |
| size_t page_aligned_byte_count = RoundUp(byte_count + page_offset, kPageSize); |
| // The 'expected_ptr' is modified (if specified, ie non-null) to be page aligned to the file but |
| // not necessarily to virtual memory. mmap will page align 'expected' for us. |
| uint8_t* page_aligned_expected = |
| (expected_ptr == nullptr) ? nullptr : (expected_ptr - page_offset); |
| |
| size_t redzone_size = 0; |
| if (RUNNING_ON_MEMORY_TOOL && kMemoryToolAddsRedzones && expected_ptr == nullptr) { |
| redzone_size = kPageSize; |
| page_aligned_byte_count += redzone_size; |
| } |
| |
| uint8_t* actual = reinterpret_cast<uint8_t*>(MapInternal(page_aligned_expected, |
| page_aligned_byte_count, |
| prot, |
| flags, |
| fd, |
| page_aligned_offset, |
| low_4gb)); |
| if (actual == MAP_FAILED) { |
| if (error_msg != nullptr) { |
| auto saved_errno = errno; |
| |
| PrintFileToLog("/proc/self/maps", LogSeverity::WARNING); |
| |
| *error_msg = StringPrintf("mmap(%p, %zd, 0x%x, 0x%x, %d, %" PRId64 |
| ") of file '%s' failed: %s. See process maps in the log.", |
| page_aligned_expected, page_aligned_byte_count, prot, flags, fd, |
| static_cast<int64_t>(page_aligned_offset), filename, |
| strerror(saved_errno)); |
| } |
| return nullptr; |
| } |
| std::ostringstream check_map_request_error_msg; |
| if (!CheckMapRequest(expected_ptr, actual, page_aligned_byte_count, error_msg)) { |
| return nullptr; |
| } |
| if (redzone_size != 0) { |
| const uint8_t *real_start = actual + page_offset; |
| const uint8_t *real_end = actual + page_offset + byte_count; |
| const uint8_t *mapping_end = actual + page_aligned_byte_count; |
| |
| MEMORY_TOOL_MAKE_NOACCESS(actual, real_start - actual); |
| MEMORY_TOOL_MAKE_NOACCESS(real_end, mapping_end - real_end); |
| page_aligned_byte_count -= redzone_size; |
| } |
| |
| return new MemMap(filename, actual + page_offset, byte_count, actual, page_aligned_byte_count, |
| prot, reuse, redzone_size); |
| } |
| |
| MemMap::~MemMap() { |
| if (base_begin_ == nullptr && base_size_ == 0) { |
| return; |
| } |
| |
| // Unlike Valgrind, AddressSanitizer requires that all manually poisoned memory is unpoisoned |
| // before it is returned to the system. |
| if (redzone_size_ != 0) { |
| MEMORY_TOOL_MAKE_UNDEFINED( |
| reinterpret_cast<char*>(base_begin_) + base_size_ - redzone_size_, |
| redzone_size_); |
| } |
| |
| if (!reuse_) { |
| MEMORY_TOOL_MAKE_UNDEFINED(base_begin_, base_size_); |
| int result = munmap(base_begin_, base_size_); |
| if (result == -1) { |
| PLOG(FATAL) << "munmap failed"; |
| } |
| } |
| |
| // Remove it from maps_. |
| MutexLock mu(Thread::Current(), *Locks::mem_maps_lock_); |
| bool found = false; |
| DCHECK(maps_ != nullptr); |
| for (auto it = maps_->lower_bound(base_begin_), end = maps_->end(); |
| it != end && it->first == base_begin_; ++it) { |
| if (it->second == this) { |
| found = true; |
| maps_->erase(it); |
| break; |
| } |
| } |
| CHECK(found) << "MemMap not found"; |
| } |
| |
| MemMap::MemMap(const std::string& name, uint8_t* begin, size_t size, void* base_begin, |
| size_t base_size, int prot, bool reuse, size_t redzone_size) |
| : name_(name), begin_(begin), size_(size), base_begin_(base_begin), base_size_(base_size), |
| prot_(prot), reuse_(reuse), redzone_size_(redzone_size) { |
| if (size_ == 0) { |
| CHECK(begin_ == nullptr); |
| CHECK(base_begin_ == nullptr); |
| CHECK_EQ(base_size_, 0U); |
| } else { |
| CHECK(begin_ != nullptr); |
| CHECK(base_begin_ != nullptr); |
| CHECK_NE(base_size_, 0U); |
| |
| // Add it to maps_. |
| MutexLock mu(Thread::Current(), *Locks::mem_maps_lock_); |
| DCHECK(maps_ != nullptr); |
| maps_->insert(std::make_pair(base_begin_, this)); |
| } |
| } |
| |
| MemMap* MemMap::RemapAtEnd(uint8_t* new_end, const char* tail_name, int tail_prot, |
| std::string* error_msg, bool use_ashmem) { |
| DCHECK_GE(new_end, Begin()); |
| DCHECK_LE(new_end, End()); |
| DCHECK_LE(begin_ + size_, reinterpret_cast<uint8_t*>(base_begin_) + base_size_); |
| DCHECK_ALIGNED(begin_, kPageSize); |
| DCHECK_ALIGNED(base_begin_, kPageSize); |
| DCHECK_ALIGNED(reinterpret_cast<uint8_t*>(base_begin_) + base_size_, kPageSize); |
| DCHECK_ALIGNED(new_end, kPageSize); |
| uint8_t* old_end = begin_ + size_; |
| uint8_t* old_base_end = reinterpret_cast<uint8_t*>(base_begin_) + base_size_; |
| uint8_t* new_base_end = new_end; |
| DCHECK_LE(new_base_end, old_base_end); |
| if (new_base_end == old_base_end) { |
| return new MemMap(tail_name, nullptr, 0, nullptr, 0, tail_prot, false); |
| } |
| size_ = new_end - reinterpret_cast<uint8_t*>(begin_); |
| base_size_ = new_base_end - reinterpret_cast<uint8_t*>(base_begin_); |
| DCHECK_LE(begin_ + size_, reinterpret_cast<uint8_t*>(base_begin_) + base_size_); |
| size_t tail_size = old_end - new_end; |
| uint8_t* tail_base_begin = new_base_end; |
| size_t tail_base_size = old_base_end - new_base_end; |
| DCHECK_EQ(tail_base_begin + tail_base_size, old_base_end); |
| DCHECK_ALIGNED(tail_base_size, kPageSize); |
| |
| int int_fd = -1; |
| int flags = MAP_PRIVATE | MAP_ANONYMOUS; |
| if (use_ashmem) { |
| // android_os_Debug.cpp read_mapinfo assumes all ashmem regions associated with the VM are |
| // prefixed "dalvik-". |
| std::string debug_friendly_name("dalvik-"); |
| debug_friendly_name += tail_name; |
| int_fd = ashmem_create_region(debug_friendly_name.c_str(), tail_base_size); |
| flags = MAP_PRIVATE | MAP_FIXED; |
| if (int_fd == -1) { |
| *error_msg = StringPrintf("ashmem_create_region failed for '%s': %s", |
| tail_name, strerror(errno)); |
| return nullptr; |
| } |
| } |
| ScopedFd fd(int_fd); |
| |
| MEMORY_TOOL_MAKE_UNDEFINED(tail_base_begin, tail_base_size); |
| // Unmap/map the tail region. |
| int result = munmap(tail_base_begin, tail_base_size); |
| if (result == -1) { |
| PrintFileToLog("/proc/self/maps", LogSeverity::WARNING); |
| *error_msg = StringPrintf("munmap(%p, %zd) failed for '%s'. See process maps in the log.", |
| tail_base_begin, tail_base_size, name_.c_str()); |
| return nullptr; |
| } |
| // Don't cause memory allocation between the munmap and the mmap |
| // calls. Otherwise, libc (or something else) might take this memory |
| // region. Note this isn't perfect as there's no way to prevent |
| // other threads to try to take this memory region here. |
| uint8_t* actual = reinterpret_cast<uint8_t*>(mmap(tail_base_begin, tail_base_size, tail_prot, |
| flags, fd.get(), 0)); |
| if (actual == MAP_FAILED) { |
| PrintFileToLog("/proc/self/maps", LogSeverity::WARNING); |
| *error_msg = StringPrintf("anonymous mmap(%p, %zd, 0x%x, 0x%x, %d, 0) failed. See process " |
| "maps in the log.", tail_base_begin, tail_base_size, tail_prot, flags, |
| fd.get()); |
| return nullptr; |
| } |
| return new MemMap(tail_name, actual, tail_size, actual, tail_base_size, tail_prot, false); |
| } |
| |
| void MemMap::MadviseDontNeedAndZero() { |
| if (base_begin_ != nullptr || base_size_ != 0) { |
| if (!kMadviseZeroes) { |
| memset(base_begin_, 0, base_size_); |
| } |
| int result = madvise(base_begin_, base_size_, MADV_DONTNEED); |
| if (result == -1) { |
| PLOG(WARNING) << "madvise failed"; |
| } |
| } |
| } |
| |
| bool MemMap::Sync() { |
| bool result; |
| if (redzone_size_ != 0) { |
| // To avoid valgrind errors, temporarily lift the lower-end noaccess protection before passing |
| // it to msync() as it only accepts page-aligned base address, and exclude the higher-end |
| // noaccess protection from the msync range. b/27552451. |
| uint8_t* base_begin = reinterpret_cast<uint8_t*>(base_begin_); |
| MEMORY_TOOL_MAKE_DEFINED(base_begin, begin_ - base_begin); |
| result = msync(BaseBegin(), End() - base_begin, MS_SYNC) == 0; |
| MEMORY_TOOL_MAKE_NOACCESS(base_begin, begin_ - base_begin); |
| } else { |
| result = msync(BaseBegin(), BaseSize(), MS_SYNC) == 0; |
| } |
| return result; |
| } |
| |
| bool MemMap::Protect(int prot) { |
| if (base_begin_ == nullptr && base_size_ == 0) { |
| prot_ = prot; |
| return true; |
| } |
| |
| if (mprotect(base_begin_, base_size_, prot) == 0) { |
| prot_ = prot; |
| return true; |
| } |
| |
| PLOG(ERROR) << "mprotect(" << reinterpret_cast<void*>(base_begin_) << ", " << base_size_ << ", " |
| << prot << ") failed"; |
| return false; |
| } |
| |
| bool MemMap::CheckNoGaps(MemMap* begin_map, MemMap* end_map) { |
| MutexLock mu(Thread::Current(), *Locks::mem_maps_lock_); |
| CHECK(begin_map != nullptr); |
| CHECK(end_map != nullptr); |
| CHECK(HasMemMap(begin_map)); |
| CHECK(HasMemMap(end_map)); |
| CHECK_LE(begin_map->BaseBegin(), end_map->BaseBegin()); |
| MemMap* map = begin_map; |
| while (map->BaseBegin() != end_map->BaseBegin()) { |
| MemMap* next_map = GetLargestMemMapAt(map->BaseEnd()); |
| if (next_map == nullptr) { |
| // Found a gap. |
| return false; |
| } |
| map = next_map; |
| } |
| return true; |
| } |
| |
| void MemMap::DumpMaps(std::ostream& os, bool terse) { |
| MutexLock mu(Thread::Current(), *Locks::mem_maps_lock_); |
| DumpMapsLocked(os, terse); |
| } |
| |
| void MemMap::DumpMapsLocked(std::ostream& os, bool terse) { |
| const auto& mem_maps = *maps_; |
| if (!terse) { |
| os << mem_maps; |
| return; |
| } |
| |
| // Terse output example: |
| // [MemMap: 0x409be000+0x20P~0x11dP+0x20P~0x61cP+0x20P prot=0x3 LinearAlloc] |
| // [MemMap: 0x451d6000+0x6bP(3) prot=0x3 large object space allocation] |
| // The details: |
| // "+0x20P" means 0x20 pages taken by a single mapping, |
| // "~0x11dP" means a gap of 0x11d pages, |
| // "+0x6bP(3)" means 3 mappings one after another, together taking 0x6b pages. |
| os << "MemMap:" << std::endl; |
| for (auto it = mem_maps.begin(), maps_end = mem_maps.end(); it != maps_end;) { |
| MemMap* map = it->second; |
| void* base = it->first; |
| CHECK_EQ(base, map->BaseBegin()); |
| os << "[MemMap: " << base; |
| ++it; |
| // Merge consecutive maps with the same protect flags and name. |
| constexpr size_t kMaxGaps = 9; |
| size_t num_gaps = 0; |
| size_t num = 1u; |
| size_t size = map->BaseSize(); |
| CHECK_ALIGNED(size, kPageSize); |
| void* end = map->BaseEnd(); |
| while (it != maps_end && |
| it->second->GetProtect() == map->GetProtect() && |
| it->second->GetName() == map->GetName() && |
| (it->second->BaseBegin() == end || num_gaps < kMaxGaps)) { |
| if (it->second->BaseBegin() != end) { |
| ++num_gaps; |
| os << "+0x" << std::hex << (size / kPageSize) << "P"; |
| if (num != 1u) { |
| os << "(" << std::dec << num << ")"; |
| } |
| size_t gap = |
| reinterpret_cast<uintptr_t>(it->second->BaseBegin()) - reinterpret_cast<uintptr_t>(end); |
| CHECK_ALIGNED(gap, kPageSize); |
| os << "~0x" << std::hex << (gap / kPageSize) << "P"; |
| num = 0u; |
| size = 0u; |
| } |
| CHECK_ALIGNED(it->second->BaseSize(), kPageSize); |
| ++num; |
| size += it->second->BaseSize(); |
| end = it->second->BaseEnd(); |
| ++it; |
| } |
| os << "+0x" << std::hex << (size / kPageSize) << "P"; |
| if (num != 1u) { |
| os << "(" << std::dec << num << ")"; |
| } |
| os << " prot=0x" << std::hex << map->GetProtect() << " " << map->GetName() << "]" << std::endl; |
| } |
| } |
| |
| bool MemMap::HasMemMap(MemMap* map) { |
| void* base_begin = map->BaseBegin(); |
| for (auto it = maps_->lower_bound(base_begin), end = maps_->end(); |
| it != end && it->first == base_begin; ++it) { |
| if (it->second == map) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| MemMap* MemMap::GetLargestMemMapAt(void* address) { |
| size_t largest_size = 0; |
| MemMap* largest_map = nullptr; |
| DCHECK(maps_ != nullptr); |
| for (auto it = maps_->lower_bound(address), end = maps_->end(); |
| it != end && it->first == address; ++it) { |
| MemMap* map = it->second; |
| CHECK(map != nullptr); |
| if (largest_size < map->BaseSize()) { |
| largest_size = map->BaseSize(); |
| largest_map = map; |
| } |
| } |
| return largest_map; |
| } |
| |
| void MemMap::Init() { |
| MutexLock mu(Thread::Current(), *Locks::mem_maps_lock_); |
| if (maps_ == nullptr) { |
| // dex2oat calls MemMap::Init twice since its needed before the runtime is created. |
| maps_ = new Maps; |
| } |
| } |
| |
| void MemMap::Shutdown() { |
| MutexLock mu(Thread::Current(), *Locks::mem_maps_lock_); |
| delete maps_; |
| maps_ = nullptr; |
| } |
| |
| void MemMap::SetSize(size_t new_size) { |
| if (new_size == base_size_) { |
| return; |
| } |
| CHECK_ALIGNED(new_size, kPageSize); |
| CHECK_EQ(base_size_, size_) << "Unsupported"; |
| CHECK_LE(new_size, base_size_); |
| MEMORY_TOOL_MAKE_UNDEFINED( |
| reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(BaseBegin()) + |
| new_size), |
| base_size_ - new_size); |
| CHECK_EQ(munmap(reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(BaseBegin()) + new_size), |
| base_size_ - new_size), 0) << new_size << " " << base_size_; |
| base_size_ = new_size; |
| size_ = new_size; |
| } |
| |
| void* MemMap::MapInternal(void* addr, |
| size_t length, |
| int prot, |
| int flags, |
| int fd, |
| off_t offset, |
| bool low_4gb) { |
| #ifdef __LP64__ |
| // When requesting low_4g memory and having an expectation, the requested range should fit into |
| // 4GB. |
| if (low_4gb && ( |
| // Start out of bounds. |
| (reinterpret_cast<uintptr_t>(addr) >> 32) != 0 || |
| // End out of bounds. For simplicity, this will fail for the last page of memory. |
| ((reinterpret_cast<uintptr_t>(addr) + length) >> 32) != 0)) { |
| LOG(ERROR) << "The requested address space (" << addr << ", " |
| << reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(addr) + length) |
| << ") cannot fit in low_4gb"; |
| return MAP_FAILED; |
| } |
| #else |
| UNUSED(low_4gb); |
| #endif |
| DCHECK_ALIGNED(length, kPageSize); |
| if (low_4gb) { |
| DCHECK_EQ(flags & MAP_FIXED, 0); |
| } |
| // TODO: |
| // A page allocator would be a useful abstraction here, as |
| // 1) It is doubtful that MAP_32BIT on x86_64 is doing the right job for us |
| void* actual = MAP_FAILED; |
| #if USE_ART_LOW_4G_ALLOCATOR |
| // MAP_32BIT only available on x86_64. |
| if (low_4gb && addr == nullptr) { |
| bool first_run = true; |
| |
| MutexLock mu(Thread::Current(), *Locks::mem_maps_lock_); |
| for (uintptr_t ptr = next_mem_pos_; ptr < 4 * GB; ptr += kPageSize) { |
| // Use maps_ as an optimization to skip over large maps. |
| // Find the first map which is address > ptr. |
| auto it = maps_->upper_bound(reinterpret_cast<void*>(ptr)); |
| if (it != maps_->begin()) { |
| auto before_it = it; |
| --before_it; |
| // Start at the end of the map before the upper bound. |
| ptr = std::max(ptr, reinterpret_cast<uintptr_t>(before_it->second->BaseEnd())); |
| CHECK_ALIGNED(ptr, kPageSize); |
| } |
| while (it != maps_->end()) { |
| // How much space do we have until the next map? |
| size_t delta = reinterpret_cast<uintptr_t>(it->first) - ptr; |
| // If the space may be sufficient, break out of the loop. |
| if (delta >= length) { |
| break; |
| } |
| // Otherwise, skip to the end of the map. |
| ptr = reinterpret_cast<uintptr_t>(it->second->BaseEnd()); |
| CHECK_ALIGNED(ptr, kPageSize); |
| ++it; |
| } |
| |
| // Try to see if we get lucky with this address since none of the ART maps overlap. |
| actual = TryMemMapLow4GB(reinterpret_cast<void*>(ptr), length, prot, flags, fd, offset); |
| if (actual != MAP_FAILED) { |
| next_mem_pos_ = reinterpret_cast<uintptr_t>(actual) + length; |
| return actual; |
| } |
| |
| if (4U * GB - ptr < length) { |
| // Not enough memory until 4GB. |
| if (first_run) { |
| // Try another time from the bottom; |
| ptr = LOW_MEM_START - kPageSize; |
| first_run = false; |
| continue; |
| } else { |
| // Second try failed. |
| break; |
| } |
| } |
| |
| uintptr_t tail_ptr; |
| |
| // Check pages are free. |
| bool safe = true; |
| for (tail_ptr = ptr; tail_ptr < ptr + length; tail_ptr += kPageSize) { |
| if (msync(reinterpret_cast<void*>(tail_ptr), kPageSize, 0) == 0) { |
| safe = false; |
| break; |
| } else { |
| DCHECK_EQ(errno, ENOMEM); |
| } |
| } |
| |
| next_mem_pos_ = tail_ptr; // update early, as we break out when we found and mapped a region |
| |
| if (safe == true) { |
| actual = TryMemMapLow4GB(reinterpret_cast<void*>(ptr), length, prot, flags, fd, offset); |
| if (actual != MAP_FAILED) { |
| return actual; |
| } |
| } else { |
| // Skip over last page. |
| ptr = tail_ptr; |
| } |
| } |
| |
| if (actual == MAP_FAILED) { |
| LOG(ERROR) << "Could not find contiguous low-memory space."; |
| errno = ENOMEM; |
| } |
| } else { |
| actual = mmap(addr, length, prot, flags, fd, offset); |
| } |
| |
| #else |
| #if defined(__LP64__) |
| if (low_4gb && addr == nullptr) { |
| flags |= MAP_32BIT; |
| } |
| #endif |
| actual = mmap(addr, length, prot, flags, fd, offset); |
| #endif |
| return actual; |
| } |
| |
| std::ostream& operator<<(std::ostream& os, const MemMap& mem_map) { |
| os << StringPrintf("[MemMap: %p-%p prot=0x%x %s]", |
| mem_map.BaseBegin(), mem_map.BaseEnd(), mem_map.GetProtect(), |
| mem_map.GetName().c_str()); |
| return os; |
| } |
| |
| void MemMap::TryReadable() { |
| if (base_begin_ == nullptr && base_size_ == 0) { |
| return; |
| } |
| CHECK_NE(prot_ & PROT_READ, 0); |
| volatile uint8_t* begin = reinterpret_cast<volatile uint8_t*>(base_begin_); |
| volatile uint8_t* end = begin + base_size_; |
| DCHECK(IsAligned<kPageSize>(begin)); |
| DCHECK(IsAligned<kPageSize>(end)); |
| // Read the first byte of each page. Use volatile to prevent the compiler from optimizing away the |
| // reads. |
| for (volatile uint8_t* ptr = begin; ptr < end; ptr += kPageSize) { |
| // This read could fault if protection wasn't set correctly. |
| uint8_t value = *ptr; |
| UNUSED(value); |
| } |
| } |
| |
| } // namespace art |
