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
|
/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <AK/Bitmap.h>
#include <AK/NonnullRefPtr.h>
#include <AK/RefPtr.h>
#include <AK/Vector.h>
#include <Kernel/Assertions.h>
#include <Kernel/VM/PhysicalPage.h>
#include <Kernel/VM/PhysicalRegion.h>
namespace Kernel {
NonnullRefPtr<PhysicalRegion> PhysicalRegion::create(PhysicalAddress lower, PhysicalAddress upper)
{
return adopt(*new PhysicalRegion(lower, upper));
}
PhysicalRegion::PhysicalRegion(PhysicalAddress lower, PhysicalAddress upper)
: m_lower(lower)
, m_upper(upper)
, m_bitmap(Bitmap::create())
{
}
void PhysicalRegion::expand(PhysicalAddress lower, PhysicalAddress upper)
{
ASSERT(!m_pages);
m_lower = lower;
m_upper = upper;
}
unsigned PhysicalRegion::finalize_capacity()
{
ASSERT(!m_pages);
m_pages = (m_upper.get() - m_lower.get()) / PAGE_SIZE;
m_bitmap.grow(m_pages, false);
return size();
}
NonnullRefPtrVector<PhysicalPage> PhysicalRegion::take_contiguous_free_pages(size_t count, bool supervisor)
{
ASSERT(m_pages);
ASSERT(m_used != m_pages);
NonnullRefPtrVector<PhysicalPage> physical_pages;
physical_pages.ensure_capacity(count);
auto first_contiguous_page = find_contiguous_free_pages(count);
for (size_t index = 0; index < count; index++)
physical_pages.append(PhysicalPage::create(m_lower.offset(PAGE_SIZE * (index + first_contiguous_page)), supervisor));
return physical_pages;
}
unsigned PhysicalRegion::find_contiguous_free_pages(size_t count)
{
ASSERT(count != 0);
// search from the last page we allocated
auto range = find_and_allocate_contiguous_range(count);
ASSERT(range.has_value());
return range.value();
}
Optional<unsigned> PhysicalRegion::find_and_allocate_contiguous_range(size_t count)
{
ASSERT(count != 0);
size_t found_pages_count = 0;
auto first_index = m_bitmap.find_longest_range_of_unset_bits(count, found_pages_count);
if (!first_index.has_value())
return {};
auto page = first_index.value();
if (count == found_pages_count) {
for (unsigned page_index = page; page_index < (page + count); page_index++) {
m_bitmap.set(page_index, true);
}
m_used += count;
m_last = page + count;
return page;
}
return {};
}
RefPtr<PhysicalPage> PhysicalRegion::take_free_page(bool supervisor)
{
ASSERT(m_pages);
if (m_used == m_pages)
return nullptr;
return PhysicalPage::create(m_lower.offset(find_contiguous_free_pages(1) * PAGE_SIZE), supervisor);
}
void PhysicalRegion::return_page_at(PhysicalAddress addr)
{
ASSERT(m_pages);
if (m_used == 0) {
ASSERT_NOT_REACHED();
}
ptrdiff_t local_offset = addr.get() - m_lower.get();
ASSERT(local_offset >= 0);
ASSERT((FlatPtr)local_offset < (FlatPtr)(m_pages * PAGE_SIZE));
auto page = (FlatPtr)local_offset / PAGE_SIZE;
if (page < m_last)
m_last = page;
m_bitmap.set(page, false);
m_used--;
}
}
|
