jcs.org
Serenity Operating System
1/*
2 * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
22 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
23 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include <AK/Assertions.h>
28#include <AK/NonnullOwnPtr.h>
29#include <AK/kmalloc.h>
30#include <LibJS/Heap/HeapBlock.h>
31#include <stdio.h>
32#include <sys/mman.h>
33
34namespace JS {
35
36NonnullOwnPtr<HeapBlock> HeapBlock::create_with_cell_size(Heap& heap, size_t cell_size)
37{
38 char name[64];
39 snprintf(name, sizeof(name), "LibJS: HeapBlock(%zu)", cell_size);
40#ifdef __serenity__
41 auto* block = (HeapBlock*)serenity_mmap(nullptr, block_size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0, block_size, name);
42#else
43 auto* block = (HeapBlock*)aligned_alloc(block_size, block_size);
44#endif
45 ASSERT(block != MAP_FAILED);
46 new (block) HeapBlock(heap, cell_size);
47 return NonnullOwnPtr<HeapBlock>(NonnullOwnPtr<HeapBlock>::Adopt, *block);
48}
49
50void HeapBlock::operator delete(void* ptr)
51{
52#ifdef __serenity__
53 int rc = munmap(ptr, block_size);
54 ASSERT(rc == 0);
55#else
56 free(ptr);
57#endif
58}
59
60HeapBlock::HeapBlock(Heap& heap, size_t cell_size)
61 : m_heap(heap)
62 , m_cell_size(cell_size)
63{
64 for (size_t i = 0; i < cell_count(); ++i) {
65 auto* freelist_entry = static_cast<FreelistEntry*>(cell(i));
66 freelist_entry->set_live(false);
67 if (i == cell_count() - 1)
68 freelist_entry->next = nullptr;
69 else
70 freelist_entry->next = static_cast<FreelistEntry*>(cell(i + 1));
71 }
72 m_freelist = static_cast<FreelistEntry*>(cell(0));
73}
74
75Cell* HeapBlock::allocate()
76{
77 if (!m_freelist)
78 return nullptr;
79 return exchange(m_freelist, m_freelist->next);
80}
81
82void HeapBlock::deallocate(Cell* cell)
83{
84 ASSERT(cell->is_live());
85 ASSERT(!cell->is_marked());
86 cell->~Cell();
87 auto* freelist_entry = static_cast<FreelistEntry*>(cell);
88 freelist_entry->set_live(false);
89 freelist_entry->next = m_freelist;
90 m_freelist = freelist_entry;
91}
92
93}