blob: d08bfdeb39c1d90875f4596ddd58282edfb629e9 (
plain)
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
|
// Copyright 2018 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package pagetables
import (
"unsafe"
"gvisor.dev/gvisor/pkg/usermem"
)
// newAlignedPTEs returns a set of aligned PTEs.
func newAlignedPTEs() *PTEs {
ptes := new(PTEs)
offset := physicalFor(ptes) & (usermem.PageSize - 1)
if offset == 0 {
// Already aligned.
return ptes
}
// Need to force an aligned allocation.
unaligned := make([]byte, (2*usermem.PageSize)-1)
offset = uintptr(unsafe.Pointer(&unaligned[0])) & (usermem.PageSize - 1)
if offset != 0 {
offset = usermem.PageSize - offset
}
return (*PTEs)(unsafe.Pointer(&unaligned[offset]))
}
// physicalFor returns the "physical" address for PTEs.
//
//go:nosplit
func physicalFor(ptes *PTEs) uintptr {
return uintptr(unsafe.Pointer(ptes))
}
// fromPhysical returns the PTEs from the "physical" address.
//
//go:nosplit
func fromPhysical(physical uintptr) *PTEs {
return (*PTEs)(unsafe.Pointer(physical))
}
|
