summaryrefslogtreecommitdiffstats
path: root/src/runtime/export_debug_amd64_test.go
blob: f9908cd494595cebaebaf430bce6f6aa7a3027b1 (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
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
// Copyright 2022 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build amd64 && linux

package runtime

import (
	"internal/abi"
	"internal/goarch"
	"unsafe"
)

type sigContext struct {
	savedRegs sigcontext
	// sigcontext.fpstate is a pointer, so we need to save
	// the its value with a fpstate1 structure.
	savedFP fpstate1
}

func sigctxtSetContextRegister(ctxt *sigctxt, x uint64) {
	ctxt.regs().rdx = x
}

func sigctxtAtTrapInstruction(ctxt *sigctxt) bool {
	return *(*byte)(unsafe.Pointer(uintptr(ctxt.rip() - 1))) == 0xcc // INT 3
}

func sigctxtStatus(ctxt *sigctxt) uint64 {
	return ctxt.r12()
}

func (h *debugCallHandler) saveSigContext(ctxt *sigctxt) {
	// Push current PC on the stack.
	rsp := ctxt.rsp() - goarch.PtrSize
	*(*uint64)(unsafe.Pointer(uintptr(rsp))) = ctxt.rip()
	ctxt.set_rsp(rsp)
	// Write the argument frame size.
	*(*uintptr)(unsafe.Pointer(uintptr(rsp - 16))) = h.argSize
	// Save current registers.
	h.sigCtxt.savedRegs = *ctxt.regs()
	h.sigCtxt.savedFP = *h.sigCtxt.savedRegs.fpstate
	h.sigCtxt.savedRegs.fpstate = nil
}

// case 0
func (h *debugCallHandler) debugCallRun(ctxt *sigctxt) {
	rsp := ctxt.rsp()
	memmove(unsafe.Pointer(uintptr(rsp)), h.argp, h.argSize)
	if h.regArgs != nil {
		storeRegArgs(ctxt.regs(), h.regArgs)
	}
	// Push return PC.
	rsp -= goarch.PtrSize
	ctxt.set_rsp(rsp)
	// The signal PC is the next PC of the trap instruction.
	*(*uint64)(unsafe.Pointer(uintptr(rsp))) = ctxt.rip()
	// Set PC to call and context register.
	ctxt.set_rip(uint64(h.fv.fn))
	sigctxtSetContextRegister(ctxt, uint64(uintptr(unsafe.Pointer(h.fv))))
}

// case 1
func (h *debugCallHandler) debugCallReturn(ctxt *sigctxt) {
	rsp := ctxt.rsp()
	memmove(h.argp, unsafe.Pointer(uintptr(rsp)), h.argSize)
	if h.regArgs != nil {
		loadRegArgs(h.regArgs, ctxt.regs())
	}
}

// case 2
func (h *debugCallHandler) debugCallPanicOut(ctxt *sigctxt) {
	rsp := ctxt.rsp()
	memmove(unsafe.Pointer(&h.panic), unsafe.Pointer(uintptr(rsp)), 2*goarch.PtrSize)
}

// case 8
func (h *debugCallHandler) debugCallUnsafe(ctxt *sigctxt) {
	rsp := ctxt.rsp()
	reason := *(*string)(unsafe.Pointer(uintptr(rsp)))
	h.err = plainError(reason)
}

// case 16
func (h *debugCallHandler) restoreSigContext(ctxt *sigctxt) {
	// Restore all registers except RIP and RSP.
	rip, rsp := ctxt.rip(), ctxt.rsp()
	fp := ctxt.regs().fpstate
	*ctxt.regs() = h.sigCtxt.savedRegs
	ctxt.regs().fpstate = fp
	*fp = h.sigCtxt.savedFP
	ctxt.set_rip(rip)
	ctxt.set_rsp(rsp)
}

// storeRegArgs sets up argument registers in the signal
// context state from an abi.RegArgs.
//
// Both src and dst must be non-nil.
func storeRegArgs(dst *sigcontext, src *abi.RegArgs) {
	dst.rax = uint64(src.Ints[0])
	dst.rbx = uint64(src.Ints[1])
	dst.rcx = uint64(src.Ints[2])
	dst.rdi = uint64(src.Ints[3])
	dst.rsi = uint64(src.Ints[4])
	dst.r8 = uint64(src.Ints[5])
	dst.r9 = uint64(src.Ints[6])
	dst.r10 = uint64(src.Ints[7])
	dst.r11 = uint64(src.Ints[8])
	for i := range src.Floats {
		dst.fpstate._xmm[i].element[0] = uint32(src.Floats[i] >> 0)
		dst.fpstate._xmm[i].element[1] = uint32(src.Floats[i] >> 32)
	}
}

func loadRegArgs(dst *abi.RegArgs, src *sigcontext) {
	dst.Ints[0] = uintptr(src.rax)
	dst.Ints[1] = uintptr(src.rbx)
	dst.Ints[2] = uintptr(src.rcx)
	dst.Ints[3] = uintptr(src.rdi)
	dst.Ints[4] = uintptr(src.rsi)
	dst.Ints[5] = uintptr(src.r8)
	dst.Ints[6] = uintptr(src.r9)
	dst.Ints[7] = uintptr(src.r10)
	dst.Ints[8] = uintptr(src.r11)
	for i := range dst.Floats {
		dst.Floats[i] = uint64(src.fpstate._xmm[i].element[0]) << 0
		dst.Floats[i] |= uint64(src.fpstate._xmm[i].element[1]) << 32
	}
}