| // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| #include "vm/globals.h" |
| #if defined(HOST_OS_LINUX) |
| |
| #include "vm/virtual_memory.h" |
| |
| #include <errno.h> |
| #include <sys/mman.h> |
| #include <unistd.h> |
| |
| #include "platform/assert.h" |
| #include "platform/utils.h" |
| |
| #include "vm/isolate.h" |
| |
| namespace dart { |
| |
| // standard MAP_FAILED causes "error: use of old-style cast" as it |
| // defines MAP_FAILED as ((void *) -1) |
| #undef MAP_FAILED |
| #define MAP_FAILED reinterpret_cast<void*>(-1) |
| |
| uword VirtualMemory::page_size_ = 0; |
| |
| void VirtualMemory::Init() { |
| page_size_ = getpagesize(); |
| } |
| |
| static void unmap(void* address, intptr_t size) { |
| if (size == 0) { |
| return; |
| } |
| |
| if (munmap(address, size) != 0) { |
| int error = errno; |
| const int kBufferSize = 1024; |
| char error_buf[kBufferSize]; |
| FATAL2("munmap error: %d (%s)", error, |
| Utils::StrError(error, error_buf, kBufferSize)); |
| } |
| } |
| |
| VirtualMemory* VirtualMemory::Allocate(intptr_t size, |
| bool is_executable, |
| const char* name) { |
| ASSERT(Utils::IsAligned(size, page_size_)); |
| int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0); |
| void* address = mmap(NULL, size, prot, MAP_PRIVATE | MAP_ANON, -1, 0); |
| if (address == MAP_FAILED) { |
| return NULL; |
| } |
| MemoryRegion region(address, size); |
| return new VirtualMemory(region, region); |
| } |
| |
| VirtualMemory* VirtualMemory::AllocateAligned(intptr_t size, |
| intptr_t alignment, |
| bool is_executable, |
| const char* name) { |
| ASSERT(Utils::IsAligned(size, page_size_)); |
| ASSERT(Utils::IsAligned(alignment, page_size_)); |
| intptr_t allocated_size = size + alignment; |
| int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0); |
| void* address = |
| mmap(NULL, allocated_size, prot, MAP_PRIVATE | MAP_ANON, -1, 0); |
| if (address == MAP_FAILED) { |
| return NULL; |
| } |
| |
| uword base = reinterpret_cast<uword>(address); |
| uword aligned_base = Utils::RoundUp(base, alignment); |
| ASSERT(base <= aligned_base); |
| |
| if (base != aligned_base) { |
| uword extra_leading_size = aligned_base - base; |
| unmap(reinterpret_cast<void*>(base), extra_leading_size); |
| allocated_size -= extra_leading_size; |
| } |
| |
| if (allocated_size != size) { |
| uword extra_trailing_size = allocated_size - size; |
| unmap(reinterpret_cast<void*>(aligned_base + size), extra_trailing_size); |
| } |
| |
| MemoryRegion region(reinterpret_cast<void*>(aligned_base), size); |
| return new VirtualMemory(region, region); |
| } |
| |
| VirtualMemory::~VirtualMemory() { |
| if (vm_owns_region()) { |
| unmap(reserved_.pointer(), reserved_.size()); |
| } |
| } |
| |
| bool VirtualMemory::FreeSubSegment(void* address, |
| intptr_t size) { |
| unmap(address, size); |
| return true; |
| } |
| |
| void VirtualMemory::Protect(void* address, intptr_t size, Protection mode) { |
| #if defined(DEBUG) |
| Thread* thread = Thread::Current(); |
| ASSERT((thread == nullptr) || thread->IsMutatorThread() || |
| thread->isolate()->mutator_thread()->IsAtSafepoint()); |
| #endif |
| uword start_address = reinterpret_cast<uword>(address); |
| uword end_address = start_address + size; |
| uword page_address = Utils::RoundDown(start_address, PageSize()); |
| int prot = 0; |
| switch (mode) { |
| case kNoAccess: |
| prot = PROT_NONE; |
| break; |
| case kReadOnly: |
| prot = PROT_READ; |
| break; |
| case kReadWrite: |
| prot = PROT_READ | PROT_WRITE; |
| break; |
| case kReadExecute: |
| prot = PROT_READ | PROT_EXEC; |
| break; |
| case kReadWriteExecute: |
| prot = PROT_READ | PROT_WRITE | PROT_EXEC; |
| break; |
| } |
| if (mprotect(reinterpret_cast<void*>(page_address), |
| end_address - page_address, prot) != 0) { |
| int error = errno; |
| const int kBufferSize = 1024; |
| char error_buf[kBufferSize]; |
| FATAL2("mprotect error: %d (%s)", error, |
| Utils::StrError(error, error_buf, kBufferSize)); |
| } |
| } |
| |
| } // namespace dart |
| |
| #endif // defined(HOST_OS_LINUX) |