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
|
// 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.
// +build amd64
package ring0
import (
"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
"gvisor.dev/gvisor/pkg/sentry/usermem"
)
var (
// UserspaceSize is the total size of userspace.
UserspaceSize = uintptr(1) << (VirtualAddressBits() - 1)
// MaximumUserAddress is the largest possible user address.
MaximumUserAddress = (UserspaceSize - 1) & ^uintptr(usermem.PageSize-1)
// KernelStartAddress is the starting kernel address.
KernelStartAddress = ^uintptr(0) - (UserspaceSize - 1)
)
// Segment indices and Selectors.
const (
// Index into GDT array.
_ = iota // Null descriptor first.
_ // Reserved (Linux is kernel 32).
segKcode // Kernel code (64-bit).
segKdata // Kernel data.
segUcode32 // User code (32-bit).
segUdata // User data.
segUcode64 // User code (64-bit).
segTss // Task segment descriptor.
segTssHi // Upper bits for TSS.
segLast // Last segment (terminal, not included).
)
// Selectors.
const (
Kcode Selector = segKcode << 3
Kdata Selector = segKdata << 3
Ucode32 Selector = (segUcode32 << 3) | 3
Udata Selector = (segUdata << 3) | 3
Ucode64 Selector = (segUcode64 << 3) | 3
Tss Selector = segTss << 3
)
// Standard segments.
var (
UserCodeSegment32 SegmentDescriptor
UserDataSegment SegmentDescriptor
UserCodeSegment64 SegmentDescriptor
KernelCodeSegment SegmentDescriptor
KernelDataSegment SegmentDescriptor
)
// KernelOpts has initialization options for the kernel.
type KernelOpts struct {
// PageTables are the kernel pagetables; this must be provided.
PageTables *pagetables.PageTables
}
// KernelArchState contains architecture-specific state.
type KernelArchState struct {
KernelOpts
// globalIDT is our set of interrupt gates.
globalIDT idt64
}
// CPUArchState contains CPU-specific arch state.
type CPUArchState struct {
// stack is the stack used for interrupts on this CPU.
stack [256]byte
// errorCode is the error code from the last exception.
errorCode uintptr
// errorType indicates the type of error code here, it is always set
// along with the errorCode value above.
//
// It will either by 1, which indicates a user error, or 0 indicating a
// kernel error. If the error code below returns false (kernel error),
// then it cannot provide relevant information about the last
// exception.
errorType uintptr
// gdt is the CPU's descriptor table.
gdt descriptorTable
// tss is the CPU's task state.
tss TaskState64
}
// ErrorCode returns the last error code.
//
// The returned boolean indicates whether the error code corresponds to the
// last user error or not. If it does not, then fault information must be
// ignored. This is generally the result of a kernel fault while servicing a
// user fault.
//
//go:nosplit
func (c *CPU) ErrorCode() (value uintptr, user bool) {
return c.errorCode, c.errorType != 0
}
// ClearErrorCode resets the error code.
//
//go:nosplit
func (c *CPU) ClearErrorCode() {
c.errorCode = 0 // No code.
c.errorType = 1 // User mode.
}
// SwitchArchOpts are embedded in SwitchOpts.
type SwitchArchOpts struct {
// UserPCID indicates that the application PCID to be used on switch,
// assuming that PCIDs are supported.
//
// Per pagetables_x86.go, a zero PCID implies a flush.
UserPCID uint16
// KernelPCID indicates that the kernel PCID to be used on return,
// assuming that PCIDs are supported.
//
// Per pagetables_x86.go, a zero PCID implies a flush.
KernelPCID uint16
}
func init() {
KernelCodeSegment.setCode64(0, 0, 0)
KernelDataSegment.setData(0, 0xffffffff, 0)
UserCodeSegment32.setCode64(0, 0, 3)
UserDataSegment.setData(0, 0xffffffff, 3)
UserCodeSegment64.setCode64(0, 0, 3)
}
|
