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
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
use crate::VirtAddr;
use core::fmt;
use core::marker::PhantomData;
use core::ops::{Add, AddAssign, Sub, SubAssign};
use ux::*;
pub trait PageSize: Copy + Eq + PartialOrd + Ord {
const SIZE: u64;
const SIZE_AS_DEBUG_STR: &'static str;
}
pub trait NotGiantPageSize: PageSize {}
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
pub enum Size4KiB {}
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
pub enum Size2MiB {}
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
pub enum Size1GiB {}
impl PageSize for Size4KiB {
const SIZE: u64 = 4096;
const SIZE_AS_DEBUG_STR: &'static str = "4KiB";
}
impl NotGiantPageSize for Size4KiB {}
impl PageSize for Size2MiB {
const SIZE: u64 = Size4KiB::SIZE * 512;
const SIZE_AS_DEBUG_STR: &'static str = "2MiB";
}
impl NotGiantPageSize for Size2MiB {}
impl PageSize for Size1GiB {
const SIZE: u64 = Size2MiB::SIZE * 512;
const SIZE_AS_DEBUG_STR: &'static str = "1GiB";
}
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
#[repr(C)]
pub struct Page<S: PageSize = Size4KiB> {
start_address: VirtAddr,
size: PhantomData<S>,
}
impl<S: PageSize> Page<S> {
pub const SIZE: u64 = S::SIZE;
pub fn from_start_address(address: VirtAddr) -> Result<Self, ()> {
if !address.is_aligned(S::SIZE) {
return Err(());
}
Ok(Page::containing_address(address))
}
pub fn containing_address(address: VirtAddr) -> Self {
Page {
start_address: address.align_down(S::SIZE),
size: PhantomData,
}
}
pub fn start_address(&self) -> VirtAddr {
self.start_address
}
pub const fn size(&self) -> u64 {
S::SIZE
}
pub fn p4_index(&self) -> u9 {
self.start_address().p4_index()
}
pub fn p3_index(&self) -> u9 {
self.start_address().p3_index()
}
pub fn range(start: Self, end: Self) -> PageRange<S> {
PageRange { start, end }
}
pub fn range_inclusive(start: Self, end: Self) -> PageRangeInclusive<S> {
PageRangeInclusive { start, end }
}
}
impl<S: NotGiantPageSize> Page<S> {
pub fn p2_index(&self) -> u9 {
self.start_address().p2_index()
}
}
impl Page<Size1GiB> {
pub fn from_page_table_indices_1gib(p4_index: u9, p3_index: u9) -> Self {
use bit_field::BitField;
let mut addr = 0;
addr.set_bits(39..48, u64::from(p4_index));
addr.set_bits(30..39, u64::from(p3_index));
Page::containing_address(VirtAddr::new(addr))
}
}
impl Page<Size2MiB> {
pub fn from_page_table_indices_2mib(p4_index: u9, p3_index: u9, p2_index: u9) -> Self {
use bit_field::BitField;
let mut addr = 0;
addr.set_bits(39..48, u64::from(p4_index));
addr.set_bits(30..39, u64::from(p3_index));
addr.set_bits(21..30, u64::from(p2_index));
Page::containing_address(VirtAddr::new(addr))
}
}
impl Page<Size4KiB> {
pub fn from_page_table_indices(p4_index: u9, p3_index: u9, p2_index: u9, p1_index: u9) -> Self {
use bit_field::BitField;
let mut addr = 0;
addr.set_bits(39..48, u64::from(p4_index));
addr.set_bits(30..39, u64::from(p3_index));
addr.set_bits(21..30, u64::from(p2_index));
addr.set_bits(12..21, u64::from(p1_index));
Page::containing_address(VirtAddr::new(addr))
}
pub fn p1_index(&self) -> u9 {
self.start_address().p1_index()
}
}
impl<S: PageSize> fmt::Debug for Page<S> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.write_fmt(format_args!(
"Page[{}]({:#x})",
S::SIZE_AS_DEBUG_STR,
self.start_address().as_u64()
))
}
}
impl<S: PageSize> Add<u64> for Page<S> {
type Output = Self;
fn add(self, rhs: u64) -> Self::Output {
Page::containing_address(self.start_address() + rhs * u64::from(S::SIZE))
}
}
impl<S: PageSize> AddAssign<u64> for Page<S> {
fn add_assign(&mut self, rhs: u64) {
*self = self.clone() + rhs;
}
}
impl<S: PageSize> Sub<u64> for Page<S> {
type Output = Self;
fn sub(self, rhs: u64) -> Self::Output {
Page::containing_address(self.start_address() - rhs * u64::from(S::SIZE))
}
}
impl<S: PageSize> SubAssign<u64> for Page<S> {
fn sub_assign(&mut self, rhs: u64) {
*self = self.clone() - rhs;
}
}
impl<S: PageSize> Sub<Self> for Page<S> {
type Output = u64;
fn sub(self, rhs: Self) -> Self::Output {
(self.start_address - rhs.start_address) / S::SIZE
}
}
#[derive(Clone, Copy, PartialEq, Eq)]
#[repr(C)]
pub struct PageRange<S: PageSize = Size4KiB> {
pub start: Page<S>,
pub end: Page<S>,
}
impl<S: PageSize> PageRange<S> {
pub fn is_empty(&self) -> bool {
!(self.start < self.end)
}
}
impl<S: PageSize> Iterator for PageRange<S> {
type Item = Page<S>;
fn next(&mut self) -> Option<Self::Item> {
if self.start < self.end {
let page = self.start.clone();
self.start += 1;
Some(page)
} else {
None
}
}
}
impl PageRange<Size2MiB> {
pub fn as_4kib_page_range(self) -> PageRange<Size4KiB> {
PageRange {
start: Page::containing_address(self.start.start_address()),
end: Page::containing_address(self.end.start_address()),
}
}
}
impl<S: PageSize> fmt::Debug for PageRange<S> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_struct("PageRange")
.field("start", &self.start)
.field("end", &self.end)
.finish()
}
}
#[derive(Clone, Copy, PartialEq, Eq)]
#[repr(C)]
pub struct PageRangeInclusive<S: PageSize = Size4KiB> {
pub start: Page<S>,
pub end: Page<S>,
}
impl<S: PageSize> PageRangeInclusive<S> {
pub fn is_empty(&self) -> bool {
!(self.start <= self.end)
}
}
impl<S: PageSize> Iterator for PageRangeInclusive<S> {
type Item = Page<S>;
fn next(&mut self) -> Option<Self::Item> {
if self.start <= self.end {
let page = self.start.clone();
self.start += 1;
Some(page)
} else {
None
}
}
}
impl<S: PageSize> fmt::Debug for PageRangeInclusive<S> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_struct("PageRangeInclusive")
.field("start", &self.start)
.field("end", &self.end)
.finish()
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
pub fn test_page_ranges() {
let page_size = Size4KiB::SIZE;
let number = 1000;
let start_addr = VirtAddr::new(0xdeadbeaf);
let start: Page = Page::containing_address(start_addr);
let end = start.clone() + number;
let mut range = Page::range(start.clone(), end.clone());
for i in 0..number {
assert_eq!(
range.next(),
Some(Page::containing_address(start_addr + page_size * i))
);
}
assert_eq!(range.next(), None);
let mut range_inclusive = Page::range_inclusive(start, end);
for i in 0..=number {
assert_eq!(
range_inclusive.next(),
Some(Page::containing_address(start_addr + page_size * i))
);
}
assert_eq!(range_inclusive.next(), None);
}
}