1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
/*
* Copyright (c) 2022, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Format.h>
#include <Kernel/Memory/AnonymousVMObject.h>
#include <Kernel/Memory/MemoryManager.h>
#include <Kernel/Memory/RegionTree.h>
#include <Kernel/Random.h>
namespace Kernel::Memory {
RegionTree::~RegionTree()
{
delete_all_regions_assuming_they_are_unmapped();
}
void RegionTree::delete_all_regions_assuming_they_are_unmapped()
{
// FIXME: This could definitely be done in a more efficient manner.
while (!m_regions.is_empty()) {
auto& region = *m_regions.begin();
m_regions.remove(region.vaddr().get());
delete ®ion;
}
}
ErrorOr<VirtualRange> RegionTree::allocate_range_anywhere(size_t size, size_t alignment)
{
if (!size)
return EINVAL;
VERIFY((size % PAGE_SIZE) == 0);
VERIFY((alignment % PAGE_SIZE) == 0);
if (Checked<size_t>::addition_would_overflow(size, alignment))
return EOVERFLOW;
VirtualAddress window_start = m_total_range.base();
auto allocate_from_window = [&](VirtualRange const& window) -> Optional<VirtualRange> {
// FIXME: This check is probably excluding some valid candidates when using a large alignment.
if (window.size() < (size + alignment))
return {};
FlatPtr initial_base = window.base().get();
FlatPtr aligned_base = round_up_to_power_of_two(initial_base, alignment);
VERIFY(size);
return VirtualRange { VirtualAddress(aligned_base), size };
};
for (auto it = m_regions.begin(); !it.is_end(); ++it) {
auto& region = *it;
if (window_start == region.vaddr()) {
window_start = region.range().end();
continue;
}
VirtualRange window { window_start, region.vaddr().get() - window_start.get() };
window_start = region.range().end();
if (auto maybe_range = allocate_from_window(window); maybe_range.has_value())
return maybe_range.release_value();
}
VirtualRange window { window_start, m_total_range.end().get() - window_start.get() };
if (m_total_range.contains(window)) {
if (auto maybe_range = allocate_from_window(window); maybe_range.has_value())
return maybe_range.release_value();
}
dmesgln("RegionTree: Failed to allocate anywhere: size={}, alignment={}", size, alignment);
return ENOMEM;
}
ErrorOr<VirtualRange> RegionTree::allocate_range_specific(VirtualAddress base, size_t size)
{
if (!size)
return EINVAL;
VERIFY(base.is_page_aligned());
VERIFY((size % PAGE_SIZE) == 0);
VirtualRange const range { base, size };
if (!m_total_range.contains(range))
return ENOMEM;
auto* region = m_regions.find_largest_not_above(base.offset(size - 1).get());
if (!region) {
// The range can be accommodated below the current lowest range.
return range;
}
if (region->range().intersects(range)) {
// Requested range overlaps an existing range.
return ENOMEM;
}
// Requested range fits between first region and its next neighbor.
return range;
}
ErrorOr<VirtualRange> RegionTree::allocate_range_randomized(size_t size, size_t alignment)
{
if (!size)
return EINVAL;
VERIFY((size % PAGE_SIZE) == 0);
VERIFY((alignment % PAGE_SIZE) == 0);
// FIXME: I'm sure there's a smarter way to do this.
constexpr size_t maximum_randomization_attempts = 1000;
for (size_t i = 0; i < maximum_randomization_attempts; ++i) {
VirtualAddress random_address { round_up_to_power_of_two(get_fast_random<FlatPtr>() % m_total_range.end().get(), alignment) };
if (!m_total_range.contains(random_address, size))
continue;
auto range_or_error = allocate_range_specific(random_address, size);
if (!range_or_error.is_error())
return range_or_error.release_value();
}
return allocate_range_anywhere(size, alignment);
}
ErrorOr<void> RegionTree::place_anywhere(Region& region, RandomizeVirtualAddress randomize_virtual_address, size_t size, size_t alignment)
{
SpinlockLocker locker(m_lock);
auto range = TRY(randomize_virtual_address == RandomizeVirtualAddress::Yes ? allocate_range_randomized(size, alignment) : allocate_range_anywhere(size, alignment));
region.m_range = range;
m_regions.insert(region.vaddr().get(), region);
return {};
}
ErrorOr<void> RegionTree::place_specifically(Region& region, VirtualRange const& range)
{
SpinlockLocker locker(m_lock);
auto allocated_range = TRY(allocate_range_specific(range.base(), range.size()));
region.m_range = allocated_range;
m_regions.insert(region.vaddr().get(), region);
return {};
}
bool RegionTree::remove(Region& region)
{
SpinlockLocker locker(m_lock);
return m_regions.remove(region.range().base().get());
}
Region* RegionTree::find_region_containing(VirtualAddress address)
{
SpinlockLocker locker(m_lock);
auto* region = m_regions.find_largest_not_above(address.get());
if (!region || !region->contains(address))
return nullptr;
return region;
}
Region* RegionTree::find_region_containing(VirtualRange range)
{
SpinlockLocker lock(m_lock);
auto* region = m_regions.find_largest_not_above(range.base().get());
if (!region || !region->contains(range))
return nullptr;
return region;
}
}
|
