1// Copyright 2020 the V8 project authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "v8config.h"  // NOLINT(build/include_directory)
6
7#if !defined(CPPGC_CAGED_HEAP)
8#error "Must be compiled with caged heap enabled"
9#endif
10
11#include "src/heap/cppgc/caged-heap.h"
12
13#include "include/cppgc/internal/caged-heap-local-data.h"
14#include "include/cppgc/platform.h"
15#include "src/base/bounded-page-allocator.h"
16#include "src/base/logging.h"
17#include "src/base/platform/platform.h"
18#include "src/heap/cppgc/globals.h"
19
20namespace cppgc {
21namespace internal {
22
23STATIC_ASSERT(api_constants::kCagedHeapReservationSize ==
24              kCagedHeapReservationSize);
25STATIC_ASSERT(api_constants::kCagedHeapReservationAlignment ==
26              kCagedHeapReservationAlignment);
27
28namespace {
29
30VirtualMemory ReserveCagedHeap(PageAllocator& platform_allocator) {
31  DCHECK_EQ(0u,
32            kCagedHeapReservationSize % platform_allocator.AllocatePageSize());
33
34  static constexpr size_t kAllocationTries = 4;
35  for (size_t i = 0; i < kAllocationTries; ++i) {
36    void* hint = reinterpret_cast<void*>(RoundDown(
37        reinterpret_cast<uintptr_t>(platform_allocator.GetRandomMmapAddr()),
38        kCagedHeapReservationAlignment));
39
40    VirtualMemory memory(&platform_allocator, kCagedHeapReservationSize,
41                         kCagedHeapReservationAlignment, hint);
42    if (memory.IsReserved()) return memory;
43  }
44
45  FATAL("Fatal process out of memory: Failed to reserve memory for caged heap");
46  UNREACHABLE();
47}
48
49}  // namespace
50
51CagedHeap::CagedHeap(HeapBase& heap_base, PageAllocator& platform_allocator)
52    : reserved_area_(ReserveCagedHeap(platform_allocator)) {
53  using CagedAddress = CagedHeap::AllocatorType::Address;
54
55  const bool is_not_oom = platform_allocator.SetPermissions(
56      reserved_area_.address(),
57      RoundUp(sizeof(CagedHeapLocalData), platform_allocator.CommitPageSize()),
58      PageAllocator::kReadWrite);
59  // Failing to commit the reservation means that we are out of memory.
60  CHECK(is_not_oom);
61
62  new (reserved_area_.address())
63      CagedHeapLocalData(heap_base, platform_allocator);
64
65  const CagedAddress caged_heap_start =
66      RoundUp(reinterpret_cast<CagedAddress>(reserved_area_.address()) +
67                  sizeof(CagedHeapLocalData),
68              kPageSize);
69  const size_t local_data_size_with_padding =
70      caged_heap_start -
71      reinterpret_cast<CagedAddress>(reserved_area_.address());
72
73  bounded_allocator_ = std::make_unique<v8::base::BoundedPageAllocator>(
74      &platform_allocator, caged_heap_start,
75      reserved_area_.size() - local_data_size_with_padding, kPageSize,
76      v8::base::PageInitializationMode::kAllocatedPagesMustBeZeroInitialized);
77}
78
79}  // namespace internal
80}  // namespace cppgc
81