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
|
// Copyright 2020 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 arch
import (
"encoding/binary"
"syscall"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/usermem"
)
// SignalContext64 is equivalent to struct sigcontext, the type passed as the
// second argument to signal handlers set by signal(2).
type SignalContext64 struct {
FaultAddr uint64
Regs [31]uint64
Sp uint64
Pc uint64
Pstate uint64
_pad [8]byte // __attribute__((__aligned__(16)))
Fpsimd64 FpsimdContext // size = 528
Reserved [3568]uint8
}
type aarch64Ctx struct {
Magic uint32
Size uint32
}
// FpsimdContext is equivalent to struct fpsimd_context on arm64
// (arch/arm64/include/uapi/asm/sigcontext.h).
type FpsimdContext struct {
Head aarch64Ctx
Fpsr uint32
Fpcr uint32
Vregs [64]uint64 // actually [32]uint128
}
// UContext64 is equivalent to ucontext on arm64(arch/arm64/include/uapi/asm/ucontext.h).
type UContext64 struct {
Flags uint64
Link uint64
Stack SignalStack
Sigset linux.SignalSet
// glibc uses a 1024-bit sigset_t
_pad [(1024 - 64) / 8]byte
// sigcontext must be aligned to 16-byte
_pad2 [8]byte
// last for future expansion
MContext SignalContext64
}
// NewSignalAct implements Context.NewSignalAct.
func (c *context64) NewSignalAct() NativeSignalAct {
return &SignalAct{}
}
// NewSignalStack implements Context.NewSignalStack.
func (c *context64) NewSignalStack() NativeSignalStack {
return &SignalStack{}
}
// SignalSetup implements Context.SignalSetup.
func (c *context64) SignalSetup(st *Stack, act *SignalAct, info *SignalInfo, alt *SignalStack, sigset linux.SignalSet) error {
sp := st.Bottom
if !(alt.IsEnabled() && sp == alt.Top()) {
sp -= 128
}
// Construct the UContext64 now since we need its size.
uc := &UContext64{
Flags: 0,
Stack: *alt,
MContext: SignalContext64{
Regs: c.Regs.Regs,
Sp: c.Regs.Sp,
Pc: c.Regs.Pc,
Pstate: c.Regs.Pstate,
},
Sigset: sigset,
}
ucSize := binary.Size(uc)
if ucSize < 0 {
panic("can't get size of UContext64")
}
// frameSize = ucSize + sizeof(siginfo).
// sizeof(siginfo) == 128.
// R30 stores the restorer address.
frameSize := ucSize + 128
frameBottom := (sp - usermem.Addr(frameSize)) & ^usermem.Addr(15)
sp = frameBottom + usermem.Addr(frameSize)
st.Bottom = sp
// Prior to proceeding, figure out if the frame will exhaust the range
// for the signal stack. This is not allowed, and should immediately
// force signal delivery (reverting to the default handler).
if act.IsOnStack() && alt.IsEnabled() && !alt.Contains(frameBottom) {
return syscall.EFAULT
}
// Adjust the code.
info.FixSignalCodeForUser()
// Set up the stack frame.
infoAddr, err := st.Push(info)
if err != nil {
return err
}
ucAddr, err := st.Push(uc)
if err != nil {
return err
}
// Set up registers.
c.Regs.Sp = uint64(st.Bottom)
c.Regs.Pc = act.Handler
c.Regs.Regs[0] = uint64(info.Signo)
c.Regs.Regs[1] = uint64(infoAddr)
c.Regs.Regs[2] = uint64(ucAddr)
c.Regs.Regs[30] = uint64(act.Restorer)
return nil
}
// SignalRestore implements Context.SignalRestore.
func (c *context64) SignalRestore(st *Stack, rt bool) (linux.SignalSet, SignalStack, error) {
// Copy out the stack frame.
var uc UContext64
if _, err := st.Pop(&uc); err != nil {
return 0, SignalStack{}, err
}
var info SignalInfo
if _, err := st.Pop(&info); err != nil {
return 0, SignalStack{}, err
}
// Restore registers.
c.Regs.Regs = uc.MContext.Regs
c.Regs.Pc = uc.MContext.Pc
c.Regs.Sp = uc.MContext.Sp
c.Regs.Pstate = uc.MContext.Pstate
return uc.Sigset, uc.Stack, nil
}
|
