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// Copyright 2020 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.
// Package ifuzz allows to generate and mutate PPC64 PowerISA 3.0B machine code.
// The ISA for POWER9 (the latest available at the moment) is at:
// https://openpowerfoundation.org/?resource_lib=power-isa-version-3-0
//
// A script on top of pdftotext was used to produce insns.go:
// ./powerisa30_to_syz /home/aik/Documents/ppc/power9/PowerISA_public.v3.0B.pdf > 1.go
// .
package powerpc
import (
"encoding/binary"
"errors"
"fmt"
"math/rand"
"github.com/google/syzkaller/pkg/ifuzz/iset"
)
type InsnBits struct {
Start uint // Big endian bit order.
Length uint
}
type InsnField struct {
Name string
Bits []InsnBits
}
type Insn struct {
Name string
Priv bool
Pseudo bool
Fields []InsnField // for ra/rb/rt/si/...
Opcode uint32
Mask uint32
FieldsSuffix []InsnField
OpcodeSuffix uint32
MaskSuffix uint32
insnMap *insnSetMap
generator func(cfg *iset.Config, r *rand.Rand) []byte
}
type insnSetMap map[string]*Insn
type InsnSet struct {
Insns []*Insn
modeInsns iset.ModeInsns
insnMap insnSetMap
}
const (
prefixShift = 32 - 6
prefixMask = uint32(0x3f) << prefixShift
prefixOpcode = uint32(1) << prefixShift
)
func (insn *Insn) isPrefixed() bool {
return insn.Opcode&prefixMask == prefixOpcode
}
func (insnset *InsnSet) GetInsns(mode iset.Mode, typ iset.Type) []iset.Insn {
return insnset.modeInsns[mode][typ]
}
func (insnset *InsnSet) Decode(mode iset.Mode, text []byte) (int, error) {
if len(text) < 4 {
return 0, errors.New("must be at least 4 bytes")
}
insn32 := binary.LittleEndian.Uint32(text)
if insn32&prefixMask == prefixOpcode {
insn2 := uint32(0)
for _, ins := range insnset.Insns {
if !ins.isPrefixed() || ins.Mask&insn32 != ins.Opcode {
continue
}
if len(text) < 8 {
return 0, errors.New("prefixed instruction must be at least 8 bytes")
}
insn2 = binary.LittleEndian.Uint32(text[4:])
for _, ins := range insnset.Insns {
if !ins.isPrefixed() {
continue
}
if ins.MaskSuffix&insn2 == ins.OpcodeSuffix {
return 8, nil
}
}
break
}
return 0, fmt.Errorf("unrecognised prefixed instruction %08x %08x", insn32, insn2)
}
for _, ins := range insnset.Insns {
if ins.Mask&insn32 == ins.Opcode {
return 4, nil
}
}
return 0, fmt.Errorf("unrecognised instruction %08x", insn32)
}
func (insnset *InsnSet) DecodeExt(mode iset.Mode, text []byte) (int, error) {
return 0, fmt.Errorf("no external decoder")
}
func encodeBits(n uint, ff []InsnBits) uint32 {
ret := uint32(0)
for _, f := range ff {
mask := uint(1<<f.Length) - 1
field := uint32((n & mask) << (31 - (f.Start + f.Length - 1)))
ret = ret | field
n = n >> f.Length
}
return ret
}
func (insn *Insn) Encode(cfg *iset.Config, r *rand.Rand) []byte {
if insn.Pseudo {
return insn.generator(cfg, r)
}
ret := make([]byte, 0)
ret = append(ret, insn.encodeOpcode(cfg, r, insn.Opcode, insn.Mask, insn.Fields)...)
if insn.isPrefixed() {
ret = append(ret, insn.encodeOpcode(cfg, r, insn.OpcodeSuffix, insn.MaskSuffix, insn.FieldsSuffix)...)
}
return ret
}
func (insn *Insn) encodeOpcode(cfg *iset.Config, r *rand.Rand, opcode, mask uint32, f []InsnField) []byte {
ret := make([]byte, 0)
insn32 := opcode
if len(cfg.MemRegions) != 0 {
// The PowerISA pdf parser could have missed some fields,
// randomize them there.
insn32 |= r.Uint32() & ^mask
}
for _, f := range f {
field := uint(r.Intn(1 << 16))
if f.Name == "Ap" || f.Name == "FRAp" || f.Name == "FRBp" || f.Name == "FRTp" || f.Name == "FRSp" {
// These are pairs and have to be even numbers.
field &^= 1
}
insn32 |= encodeBits(field, f.Bits)
if len(cfg.MemRegions) != 0 && (f.Name == "RA" || f.Name == "RB" || f.Name == "RS") {
val := iset.GenerateInt(cfg, r, 8)
ret = append(ret, insn.insnMap.ld64(field, val)...)
}
}
return append(ret, uint32toBytes(insn32)...)
}
func Register(insns []*Insn) {
if len(insns) == 0 {
panic("no instructions")
}
insnset := &InsnSet{
Insns: insns,
insnMap: make(map[string]*Insn),
}
for _, insn := range insnset.Insns {
insnset.insnMap[insn.Name] = insn
insn.insnMap = &insnset.insnMap
}
insnset.initPseudo()
for _, insn := range insnset.Insns {
insnset.modeInsns.Add(insn)
}
iset.Arches[iset.ArchPowerPC] = insnset
}
func (insn *Insn) Info() (string, iset.Mode, bool, bool) {
return insn.Name, insn.mode(), insn.Pseudo, insn.Priv
}
func (insn *Insn) mode() iset.Mode {
return (1 << iset.ModeLong64) | (1 << iset.ModeProt32)
}
func uint32toBytes(v uint32) []byte {
ret := make([]byte, 4)
binary.LittleEndian.PutUint32(ret, v)
return ret
}
func (insn *Insn) enc(v map[string]uint) []byte {
ret := make([]byte, 0)
ret = append(ret, insn.encOpcode(v, insn.Opcode, insn.Fields)...)
if insn.isPrefixed() {
ret = append(ret, insn.encOpcode(v, insn.OpcodeSuffix, insn.FieldsSuffix)...)
}
return ret
}
func (insn *Insn) encOpcode(v map[string]uint, opcode uint32, f []InsnField) []byte {
insn32 := opcode
for _, f := range insn.Fields {
if val, ok := v[f.Name]; ok {
insn32 |= encodeBits(val, f.Bits)
}
}
return uint32toBytes(insn32)
}
func (imap insnSetMap) ld64(reg uint, v uint64) []byte {
ret := make([]byte, 0)
// This is a widely used macro to load immediate on ppc64
// #define LOAD64(rn,name)
// addis rn,0,name##@highest \ lis rn,name##@highest
// ori rn,rn,name##@higher
// rldicr rn,rn,32,31
// oris rn,rn,name##@h
// ori rn,rn,name##@l
ret = append(ret, imap["addis"].enc(map[string]uint{
"RT": reg,
"RA": 0, // In "addis", '0' means 0, not GPR0 .
"SI": uint((v >> 48) & 0xffff)})...)
ret = append(ret, imap["ori"].enc(map[string]uint{
"RA": reg,
"RS": reg,
"UI": uint((v >> 32) & 0xffff)})...)
ret = append(ret, imap["rldicr"].enc(map[string]uint{
"RA": reg,
"RS": reg,
"SH": 32,
"ME": 31})...)
ret = append(ret, imap["oris"].enc(map[string]uint{
"RA": reg,
"RS": reg,
"UI": uint((v >> 16) & 0xffff)})...)
ret = append(ret, imap["ori"].enc(map[string]uint{
"RA": reg,
"RS": reg,
"UI": uint(v & 0xffff)})...)
return ret
}
func (imap insnSetMap) ld32(reg uint, v uint32) []byte {
ret := make([]byte, 0)
ret = append(ret, imap["addis"].enc(map[string]uint{
"RT": reg,
"RA": 0, // In "addis", '0' means 0, not GPR0
"SI": uint((v >> 16) & 0xffff)})...)
ret = append(ret, imap["ori"].enc(map[string]uint{
"RA": reg,
"RS": reg,
"UI": uint(v & 0xffff)})...)
return ret
}
func (imap insnSetMap) ldgpr32(regaddr, regval uint, addr uint64, v uint32) []byte {
ret := make([]byte, 0)
ret = append(ret, imap.ld64(regaddr, addr)...)
ret = append(ret, imap.ld32(regval, v)...)
ret = append(ret, imap["stw"].enc(map[string]uint{
"RA": regaddr,
"RS": regval})...)
return ret
}
func (imap insnSetMap) sc(lev uint) []byte {
return imap["sc"].enc(map[string]uint{"LEV": lev})
}
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