blob: 438b0ea7370bd0f20bdd5872663c8f82b488e6ee [file] [log] [blame]
// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/trace_event/heap_profiler_allocation_register.h"
#include <windows.h>
#include <stddef.h>
#include "base/bits.h"
#include "base/logging.h"
#include "base/process/process_metrics.h"
namespace base {
namespace trace_event {
namespace internal {
namespace {
size_t GetGuardSize() {
return GetPageSize();
void* AllocateGuardedVirtualMemory(size_t size) {
size = bits::Align(size, GetPageSize());
// Add space for a guard page at the end.
size_t map_size = size + GetGuardSize();
// Reserve the address space. This does not make the memory usable yet.
void* addr = VirtualAlloc(nullptr, map_size, MEM_RESERVE, PAGE_NOACCESS);
PCHECK(addr != nullptr);
// Commit the non-guard pages as read-write memory.
void* result = VirtualAlloc(addr, size, MEM_COMMIT, PAGE_READWRITE);
PCHECK(result != nullptr);
// Mark the last page of the allocated address space as guard page. (NB: The
// |PAGE_GUARD| flag is not the flag to use here, that flag can be used to
// detect and intercept access to a certain memory region. Accessing a
// |PAGE_NOACCESS| page will raise a general protection fault.) The
// read/write accessible space is still at least |min_size| bytes.
void* guard_addr =
reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(addr) + size);
result = VirtualAlloc(guard_addr, GetGuardSize(), MEM_COMMIT, PAGE_NOACCESS);
PCHECK(result != nullptr);
return addr;
void FreeGuardedVirtualMemory(void* address, size_t allocated_size) {
// For |VirtualFree|, the size passed with |MEM_RELEASE| must be 0. Windows
// automatically frees the entire region that was reserved by the
// |VirtualAlloc| with flag |MEM_RESERVE|.
VirtualFree(address, 0, MEM_RELEASE);
} // namespace internal
} // namespace trace_event
} // namespace base