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// Copyright 2024 syzkaller project authors. All rights reserved.
// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
//go:generate go run gen/gen.go gen/json/arm64.json generated/insns.go
// Package arm64 allows to generate and mutate arm64 machine code.
package arm64
import (
"encoding/binary"
"fmt"
"math/rand"
"github.com/google/syzkaller/pkg/ifuzz/iset"
)
type InsnField struct {
Name string
Start uint // Little endian bit order.
Length uint
}
type Insn struct {
Name string
OpcodeMask uint32
Opcode uint32
Fields []InsnField
AsUInt32 uint32
Operands []uint32
Pseudo bool
Priv bool
Generator func(cfg *iset.Config, r *rand.Rand) []byte // for pseudo instructions
}
type InsnSet struct {
modeInsns iset.ModeInsns
Insns []*Insn
}
func Register(insns []*Insn) {
if len(insns) == 0 {
panic("no instructions")
}
insnset := &InsnSet{
Insns: append(insns, pseudo...),
}
for _, insn := range insnset.Insns {
insnset.modeInsns.Add(insn)
}
iset.Arches[iset.ArchArm64] = insnset
templates = insns
}
func (insnset *InsnSet) GetInsns(mode iset.Mode, typ iset.Type) []iset.Insn {
return insnset.modeInsns[mode][typ]
}
func (insn *Insn) Info() (string, iset.Mode, bool, bool) {
return insn.Name, 1 << iset.ModeLong64, insn.Pseudo, insn.Priv
}
func (insn *Insn) Encode(cfg *iset.Config, r *rand.Rand) []byte {
if insn.Pseudo {
return insn.Generator(cfg, r)
}
ret := make([]byte, 4)
binary.LittleEndian.PutUint32(ret, insn.AsUInt32)
return ret
}
func (insnset *InsnSet) Decode(mode iset.Mode, text []byte) (int, error) {
if len(text) < 4 {
return 0, fmt.Errorf("must be at least 4 bytes")
}
opcode := binary.LittleEndian.Uint32(text[:4])
_, err := ParseInsn(opcode)
if err != nil {
return 0, fmt.Errorf("failed to decode %x", opcode)
}
return 4, nil
}
func (insnset *InsnSet) DecodeExt(mode iset.Mode, text []byte) (int, error) {
return 0, fmt.Errorf("no external decoder")
}
var templates []*Insn
func (insn *Insn) initFromValue(val uint32) {
operands := []uint32{}
for _, field := range insn.Fields {
extracted := extractBits(val, field.Start, field.Length)
operands = append(operands, extracted)
}
insn.Operands = operands
insn.AsUInt32 = val
}
func (insn *Insn) matchesValue(val uint32) bool {
opcode := val & insn.OpcodeMask
return opcode == insn.Opcode
}
func ParseInsn(val uint32) (Insn, error) {
for _, tmpl := range templates {
if tmpl.matchesValue(val) {
newInsn := *tmpl
newInsn.initFromValue(val)
return newInsn, nil
}
}
unknown := Insn{
Name: "unknown",
}
return unknown, fmt.Errorf("unrecognized instruction: %08x", val)
}
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