Merge branch 'develop' into aj/add-sepolia-op-program

cannon/.gitignore

@@ -9,6 +9,7 @@ example/bin
 contracts/out
 state.json
 *.json
+*.json.gz
 *.pprof
 *.out
 bin

cannon/cmd/json.go

 package cmd
 
 import (
+	"compress/gzip"
 	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
 	"os"
+	"strings"
 )
 
 func loadJSON[X any](inputPath string) (*X, error) {
 	if inputPath == "" {
 		return nil, errors.New("no path specified")
 	}
+	var f io.ReadCloser
 	f, err := os.OpenFile(inputPath, os.O_RDONLY, 0)
 	if err != nil {
 		return nil, fmt.Errorf("failed to open file %q: %w", inputPath, err)
 	}
 	defer f.Close()
+	if isGzip(inputPath) {
+		f, err = gzip.NewReader(f)
+		if err != nil {
+			return nil, fmt.Errorf("create gzip reader: %w", err)
+		}
+		defer f.Close()
+	}
 	var state X
 	if err := json.NewDecoder(f).Decode(&state); err != nil {
 		return nil, fmt.Errorf("failed to decode file %q: %w", inputPath, err)
@@ -33,6 +43,11 @@ func writeJSON[X any](outputPath string, value X, outIfEmpty bool) error {
 		}
 		defer f.Close()
 		out = f
+		if isGzip(outputPath) {
+			g := gzip.NewWriter(f)
+			defer g.Close()
+			out = g
+		}
 	} else if outIfEmpty {
 		out = os.Stdout
 	} else {
@@ -48,3 +63,7 @@ func writeJSON[X any](outputPath string, value X, outIfEmpty bool) error {
 	}
 	return nil
 }
+
+func isGzip(path string) bool {
+	return strings.HasSuffix(path, ".gz")
+}

cannon/cmd/json_test.go

+package cmd
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestRoundTripJSON(t *testing.T) {
+	dir := t.TempDir()
+	file := filepath.Join(dir, "test.json")
+	data := &jsonTestData{A: "yay", B: 3}
+	err := writeJSON(file, data, false)
+	require.NoError(t, err)
+
+	// Confirm the file is uncompressed
+	fileContent, err := os.ReadFile(file)
+	require.NoError(t, err)
+	err = json.Unmarshal(fileContent, &jsonTestData{})
+	require.NoError(t, err)
+
+	var result *jsonTestData
+	result, err = loadJSON[jsonTestData](file)
+	require.NoError(t, err)
+	require.EqualValues(t, data, result)
+}
+
+func TestRoundTripJSONWithGzip(t *testing.T) {
+	dir := t.TempDir()
+	file := filepath.Join(dir, "test.json.gz")
+	data := &jsonTestData{A: "yay", B: 3}
+	err := writeJSON(file, data, false)
+	require.NoError(t, err)
+
+	// Confirm the file isn't raw JSON
+	fileContent, err := os.ReadFile(file)
+	require.NoError(t, err)
+	err = json.Unmarshal(fileContent, &jsonTestData{})
+	require.Error(t, err, "should not be able to decode without decompressing")
+
+	var result *jsonTestData
+	result, err = loadJSON[jsonTestData](file)
+	require.NoError(t, err)
+	require.EqualValues(t, data, result)
+}
+
+type jsonTestData struct {
+	A string `json:"a"`
+	B int    `json:"b"`
+}

cannon/mipsevm/evm.go

@@ -27,6 +27,7 @@ var (
 	StepBytes4                      = crypto.Keccak256([]byte("step(bytes,bytes)"))[:4]
 	CheatBytes4                     = crypto.Keccak256([]byte("cheat(uint256,bytes32,bytes32,uint256)"))[:4]
 	LoadKeccak256PreimagePartBytes4 = crypto.Keccak256([]byte("loadKeccak256PreimagePart(uint256,bytes)"))[:4]
+	LoadLocalDataBytes4             = crypto.Keccak256([]byte("loadLocalData(uint256,bytes32,uint256,uint256)"))[:4]
 )
 
 // LoadContracts loads the Cannon contracts, from op-bindings package

cannon/mipsevm/evm_test.go

@@ -37,9 +37,12 @@ func testContractsSetup(t require.TestingT) (*Contracts, *Addresses) {
 }
 
 func SourceMapTracer(t *testing.T, contracts *Contracts, addrs *Addresses) vm.EVMLogger {
-	mipsSrcMap, err := contracts.MIPS.SourceMap([]string{"../../packages/contracts-bedrock/contracts/cannon/MIPS.sol"})
+	t.Fatal("TODO(clabby): The source map tracer is disabled until source IDs have been added to foundry artifacts.")
+
+	contractsDir := "../../packages/contracts-bedrock"
+	mipsSrcMap, err := contracts.MIPS.SourceMap([]string{path.Join(contractsDir, "src/cannon/MIPS.sol")})
 	require.NoError(t, err)
-	oracleSrcMap, err := contracts.Oracle.SourceMap([]string{"../../packages/contracts-bedrock/contracts/cannon/PreimageOracle.sol"})
+	oracleSrcMap, err := contracts.Oracle.SourceMap([]string{path.Join(contractsDir, "src/cannon/PreimageOracle.sol")})
 	require.NoError(t, err)
 
 	return srcmap.NewSourceMapTracer(map[common.Address]*srcmap.SourceMap{addrs.MIPS: mipsSrcMap, addrs.Oracle: oracleSrcMap}, os.Stdout)
@@ -76,7 +79,7 @@ func (m *MIPSEVM) Step(t *testing.T, stepWitness *StepWitness) []byte {
 		t.Logf("reading preimage key %x at offset %d", stepWitness.PreimageKey, stepWitness.PreimageOffset)
 		poInput, err := stepWitness.EncodePreimageOracleInput()
 		require.NoError(t, err, "encode preimage oracle input")
-		_, leftOverGas, err := m.env.Call(vm.AccountRef(m.addrs.Sender), m.addrs.Oracle, poInput, startingGas, big.NewInt(0))
+		_, leftOverGas, err := m.env.Call(vm.AccountRef(sender), m.addrs.Oracle, poInput, startingGas, big.NewInt(0))
 		require.NoErrorf(t, err, "evm should not fail, took %d gas", startingGas-leftOverGas)
 	}
 
@@ -171,17 +174,28 @@ func TestEVMFault(t *testing.T) {
 	env, evmState := NewEVMEnv(contracts, addrs)
 	env.Config.Tracer = tracer
 
-	programMem := []byte{0xff, 0xff, 0xff, 0xff}
-	state := &State{PC: 0, NextPC: 4, Memory: NewMemory()}
-	initialState := &State{PC: 0, NextPC: 4, Memory: state.Memory}
-	err := state.Memory.SetMemoryRange(0, bytes.NewReader(programMem))
-	require.NoError(t, err, "load program into state")
+	type testInput struct {
+		name   string
+		nextPC uint32
+		insn   uint32
+	}
+	cases := []testInput{
+		{"illegal instruction", 0, 0xFF_FF_FF_FF},
+		{"branch in delay-slot", 8, 0x11_02_00_03},
+		{"jump in delay-slot", 8, 0x0c_00_00_0c},
+	}
+
+	for _, tt := range cases {
+		t.Run(tt.name, func(t *testing.T) {
+			state := &State{PC: 0, NextPC: tt.nextPC, Memory: NewMemory()}
+			initialState := &State{PC: 0, NextPC: tt.nextPC, Memory: state.Memory}
+			state.Memory.SetMemory(0, tt.insn)
 
 			// set the return address ($ra) to jump into when test completes
 			state.Registers[31] = endAddr
 
-	goState := NewInstrumentedState(state, nil, os.Stdout, os.Stderr)
-	require.Panics(t, func() { _, _ = goState.Step(true) }, "must panic on illegal instruction")
+			us := NewInstrumentedState(state, nil, os.Stdout, os.Stderr)
+			require.Panics(t, func() { _, _ = us.Step(true) })
 
 			insnProof := initialState.Memory.MerkleProof(0)
 			stepWitness := &StepWitness{
@@ -191,10 +205,12 @@ func TestEVMFault(t *testing.T) {
 			input := stepWitness.EncodeStepInput()
 			startingGas := uint64(30_000_000)
 
-	_, _, err = env.Call(vm.AccountRef(sender), addrs.MIPS, input, startingGas, big.NewInt(0))
+			_, _, err := env.Call(vm.AccountRef(sender), addrs.MIPS, input, startingGas, big.NewInt(0))
 			require.EqualValues(t, err, vm.ErrExecutionReverted)
 			logs := evmState.Logs()
 			require.Equal(t, 0, len(logs))
+		})
+	}
 }
 
 func TestHelloEVM(t *testing.T) {

cannon/mipsevm/mips.go

@@ -180,6 +180,10 @@ func (m *InstrumentedState) handleSyscall() error {
 }
 
 func (m *InstrumentedState) handleBranch(opcode uint32, insn uint32, rtReg uint32, rs uint32) error {
+	if m.state.NextPC != m.state.PC+4 {
+		panic("branch in delay slot")
+	}
+
 	shouldBranch := false
 	if opcode == 4 || opcode == 5 { // beq/bne
 		rt := m.state.Registers[rtReg]
@@ -246,6 +250,9 @@ func (m *InstrumentedState) handleHiLo(fun uint32, rs uint32, rt uint32, storeRe
 }
 
 func (m *InstrumentedState) handleJump(linkReg uint32, dest uint32) error {
+	if m.state.NextPC != m.state.PC+4 {
+		panic("jump in delay slot")
+	}
 	prevPC := m.state.PC
 	m.state.PC = m.state.NextPC
 	m.state.NextPC = dest

cannon/mipsevm/witness.go

@@ -49,18 +49,19 @@ func (wit *StepWitness) EncodePreimageOracleInput() ([]byte, error) {
 
 	switch preimage.KeyType(wit.PreimageKey[0]) {
 	case preimage.LocalKeyType:
-		// We have no on-chain form of preparing the bootstrap pre-images onchain yet.
-		// So instead we cheat them in.
-		// In production usage there should be an on-chain contract that exposes this,
-		// rather than going through the global keccak256 oracle.
+		if len(wit.PreimageValue) > 32+8 {
+			return nil, fmt.Errorf("local pre-image exceeds maximum size of 32 bytes with key 0x%x", wit.PreimageKey)
+		}
 		var input []byte
-		input = append(input, CheatBytes4...)
-		input = append(input, uint32ToBytes32(wit.PreimageOffset)...)
+		input = append(input, LoadLocalDataBytes4...)
 		input = append(input, wit.PreimageKey[:]...)
+
+		preimagePart := wit.PreimageValue[8:]
 		var tmp [32]byte
-		copy(tmp[:], wit.PreimageValue[wit.PreimageOffset:])
+		copy(tmp[:], preimagePart)
 		input = append(input, tmp[:]...)
-		input = append(input, uint32ToBytes32(uint32(len(wit.PreimageValue))-8)...)
+		input = append(input, uint32ToBytes32(uint32(len(wit.PreimageValue)-8))...)
+		input = append(input, uint32ToBytes32(wit.PreimageOffset)...)
 		// Note: we can pad calldata to 32 byte multiple, but don't strictly have to
 		return input, nil
 	case preimage.Keccak256KeyType:

op-bindings/bindings/alphabetvm.go

@@ -30,8 +30,8 @@ var (
 
 // AlphabetVMMetaData contains all meta data concerning the AlphabetVM contract.
 var AlphabetVMMetaData = &bind.MetaData{
-	ABI: "[{\"inputs\":[{\"internalType\":\"Claim\",\"name\":\"_absolutePrestate\",\"type\":\"bytes32\"}],\"stateMutability\":\"nonpayable\",\"type\":\"constructor\"},{\"inputs\":[{\"internalType\":\"bytes\",\"name\":\"_stateData\",\"type\":\"bytes\"},{\"internalType\":\"bytes\",\"name\":\"\",\"type\":\"bytes\"}],\"name\":\"step\",\"outputs\":[{\"internalType\":\"bytes32\",\"name\":\"postState_\",\"type\":\"bytes32\"}],\"stateMutability\":\"view\",\"type\":\"function\"}]",
-	Bin: "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",
+	ABI: "[{\"inputs\":[{\"internalType\":\"Claim\",\"name\":\"_absolutePrestate\",\"type\":\"bytes32\"}],\"stateMutability\":\"nonpayable\",\"type\":\"constructor\"},{\"inputs\":[],\"name\":\"oracle\",\"outputs\":[{\"internalType\":\"contractIPreimageOracle\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"bytes\",\"name\":\"_stateData\",\"type\":\"bytes\"},{\"internalType\":\"bytes\",\"name\":\"\",\"type\":\"bytes\"}],\"name\":\"step\",\"outputs\":[{\"internalType\":\"bytes32\",\"name\":\"postState_\",\"type\":\"bytes32\"}],\"stateMutability\":\"view\",\"type\":\"function\"}]",
+	Bin: "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",
 }
 
 // AlphabetVMABI is the input ABI used to generate the binding from.
@@ -201,6 +201,37 @@ func (_AlphabetVM *AlphabetVMTransactorRaw) Transact(opts *bind.TransactOpts, me
 	return _AlphabetVM.Contract.contract.Transact(opts, method, params...)
 }
 
+// Oracle is a free data retrieval call binding the contract method 0x7dc0d1d0.
+//
+// Solidity: function oracle() view returns(address)
+func (_AlphabetVM *AlphabetVMCaller) Oracle(opts *bind.CallOpts) (common.Address, error) {
+	var out []interface{}
+	err := _AlphabetVM.contract.Call(opts, &out, "oracle")
+
+	if err != nil {
+		return *new(common.Address), err
+	}
+
+	out0 := *abi.ConvertType(out[0], new(common.Address)).(*common.Address)
+
+	return out0, err
+
+}
+
+// Oracle is a free data retrieval call binding the contract method 0x7dc0d1d0.
+//
+// Solidity: function oracle() view returns(address)
+func (_AlphabetVM *AlphabetVMSession) Oracle() (common.Address, error) {
+	return _AlphabetVM.Contract.Oracle(&_AlphabetVM.CallOpts)
+}
+
+// Oracle is a free data retrieval call binding the contract method 0x7dc0d1d0.
+//
+// Solidity: function oracle() view returns(address)
+func (_AlphabetVM *AlphabetVMCallerSession) Oracle() (common.Address, error) {
+	return _AlphabetVM.Contract.Oracle(&_AlphabetVM.CallOpts)
+}
+
 // Step is a free data retrieval call binding the contract method 0xf8e0cb96.
 //
 // Solidity: function step(bytes _stateData, bytes ) view returns(bytes32 postState_)

op-bindings/bindings/alphabetvm_more.go

@@ -9,11 +9,11 @@ import (
 	"github.com/ethereum-optimism/optimism/op-bindings/solc"
 )
 
-const AlphabetVMStorageLayoutJSON = "{\"storage\":null,\"types\":{}}"
+const AlphabetVMStorageLayoutJSON = "{\"storage\":[{\"astId\":1000,\"contract\":\"test/FaultDisputeGame.t.sol:AlphabetVM\",\"label\":\"oracle\",\"offset\":0,\"slot\":\"0\",\"type\":\"t_contract(IPreimageOracle)1001\"}],\"types\":{\"t_contract(IPreimageOracle)1001\":{\"encoding\":\"inplace\",\"label\":\"contract IPreimageOracle\",\"numberOfBytes\":\"20\"}}}"
 
 var AlphabetVMStorageLayout = new(solc.StorageLayout)
 
-var AlphabetVMDeployedBin = "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"
+var AlphabetVMDeployedBin = "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"
 
 func init() {
 	if err := json.Unmarshal([]byte(AlphabetVMStorageLayoutJSON), AlphabetVMStorageLayout); err != nil {

op-chain-ops/srcmap/solutil_test.go

 package srcmap
 
 import (
+	"path"
 	"strings"
 	"testing"
 
@@ -11,17 +12,24 @@ import (
 )
 
 func TestSourcemap(t *testing.T) {
-	sourcePath := "../../packages/contracts-bedrock/src/cannon/MIPS.sol"
+	t.Skip("TODO(clabby): This test is disabled until source IDs have been added to foundry artifacts.")
+
+	contractsDir := "../../packages/contracts-bedrock"
+	sources := []string{path.Join(contractsDir, "src/cannon/MIPS.sol")}
+	for i, source := range sources {
+		sources[i] = path.Join(contractsDir, source)
+	}
+
 	deployedByteCode := hexutil.MustDecode(bindings.MIPSDeployedBin)
 	srcMap, err := ParseSourceMap(
-		[]string{sourcePath},
+		sources,
 		deployedByteCode,
 		bindings.MIPSDeployedSourceMap)
 	require.NoError(t, err)
 
 	for i := 0; i < len(deployedByteCode); i++ {
 		info := srcMap.FormattedInfo(uint64(i))
-		if !strings.HasPrefix(info, "generated:") && !strings.HasPrefix(info, sourcePath) {
+		if strings.HasPrefix(info, "unknown") {
 			t.Fatalf("unexpected info: %q", info)
 		}
 	}

op-challenger/fault/abi_test.go

@@ -30,10 +30,11 @@ func setupFaultDisputeGame() (common.Address, *bind.TransactOpts, *backends.Simu
 	_, _, contract, err := bindings.DeployFaultDisputeGame(
 		opts,
 		backend,
-		[32]byte{0x01},
-		big.NewInt(15),
+		[32]byte{0x01},       // Absolute Prestate Claim
+		big.NewInt(15),       // Max Game Depth
 		uint64(604800),       // 7 days
-		common.Address{0xdd},
+		common.Address{0xdd}, // VM
+		common.Address{0xee}, // L2OutputOracle (Not used in Alphabet Game)
 	)
 	if err != nil {
 		return common.Address{}, nil, nil, nil, err

op-e2e/actions/l2_batcher_test.go

@@ -16,6 +16,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-e2e/e2eutils"
 	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum-optimism/optimism/op-node/rollup/derive"
+	"github.com/ethereum-optimism/optimism/op-node/rollup/sync"
 	"github.com/ethereum-optimism/optimism/op-node/testlog"
 )
 
@@ -30,7 +31,7 @@ func TestBatcher(gt *testing.T) {
 	sd := e2eutils.Setup(t, dp, defaultAlloc)
 	log := testlog.Logger(t, log.LvlDebug)
 	miner, seqEngine, sequencer := setupSequencerTest(t, sd, log)
-	verifEngine, verifier := setupVerifier(t, sd, log, miner.L1Client(t, sd.RollupCfg))
+	verifEngine, verifier := setupVerifier(t, sd, log, miner.L1Client(t, sd.RollupCfg), &sync.Config{})
 
 	rollupSeqCl := sequencer.RollupClient()
 	batcher := NewL2Batcher(log, sd.RollupCfg, &BatcherCfg{
@@ -268,7 +269,7 @@ func TestGarbageBatch(gt *testing.T) {
 		log := testlog.Logger(t, log.LvlError)
 		miner, engine, sequencer := setupSequencerTest(t, sd, log)
 
-		_, verifier := setupVerifier(t, sd, log, miner.L1Client(t, sd.RollupCfg))
+		_, verifier := setupVerifier(t, sd, log, miner.L1Client(t, sd.RollupCfg), &sync.Config{})
 
 		batcherCfg := &BatcherCfg{
 			MinL1TxSize: 0,
@@ -350,7 +351,7 @@ func TestExtendedTimeWithoutL1Batches(gt *testing.T) {
 	log := testlog.Logger(t, log.LvlError)
 	miner, engine, sequencer := setupSequencerTest(t, sd, log)
 
-	_, verifier := setupVerifier(t, sd, log, miner.L1Client(t, sd.RollupCfg))
+	_, verifier := setupVerifier(t, sd, log, miner.L1Client(t, sd.RollupCfg), &sync.Config{})
 
 	batcher := NewL2Batcher(log, sd.RollupCfg, &BatcherCfg{
 		MinL1TxSize: 0,
@@ -407,7 +408,7 @@ func TestBigL2Txs(gt *testing.T) {
 	log := testlog.Logger(t, log.LvlInfo)
 	miner, engine, sequencer := setupSequencerTest(t, sd, log)
 
-	_, verifier := setupVerifier(t, sd, log, miner.L1Client(t, sd.RollupCfg))
+	_, verifier := setupVerifier(t, sd, log, miner.L1Client(t, sd.RollupCfg), &sync.Config{})
 
 	batcher := NewL2Batcher(log, sd.RollupCfg, &BatcherCfg{
 		MinL1TxSize: 0,

op-e2e/actions/l2_sequencer.go

@@ -12,6 +12,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-node/rollup"
 	"github.com/ethereum-optimism/optimism/op-node/rollup/derive"
 	"github.com/ethereum-optimism/optimism/op-node/rollup/driver"
+	"github.com/ethereum-optimism/optimism/op-node/rollup/sync"
 )
 
 // MockL1OriginSelector is a shim to override the origin as sequencer, so we can force it to stay on an older origin.
@@ -40,7 +41,7 @@ type L2Sequencer struct {
 }
 
 func NewL2Sequencer(t Testing, log log.Logger, l1 derive.L1Fetcher, eng L2API, cfg *rollup.Config, seqConfDepth uint64) *L2Sequencer {
-	ver := NewL2Verifier(t, log, l1, eng, cfg)
+	ver := NewL2Verifier(t, log, l1, eng, cfg, &sync.Config{})
 	attrBuilder := derive.NewFetchingAttributesBuilder(cfg, l1, eng)
 	seqConfDepthL1 := driver.NewConfDepth(seqConfDepth, ver.l1State.L1Head, l1)
 	l1OriginSelector := &MockL1OriginSelector{

op-e2e/actions/l2_verifier.go

@@ -54,12 +54,11 @@ type L2API interface {
 	InfoByHash(ctx context.Context, hash common.Hash) (eth.BlockInfo, error)
 	// GetProof returns a proof of the account, it may return a nil result without error if the address was not found.
 	GetProof(ctx context.Context, address common.Address, storage []common.Hash, blockTag string) (*eth.AccountResult, error)
-	OutputV0AtBlock(ctx context.Context, blockHash common.Hash) (*eth.OutputV0, error)
 }
 
-func NewL2Verifier(t Testing, log log.Logger, l1 derive.L1Fetcher, eng L2API, cfg *rollup.Config) *L2Verifier {
+func NewL2Verifier(t Testing, log log.Logger, l1 derive.L1Fetcher, eng L2API, cfg *rollup.Config, syncCfg *sync.Config) *L2Verifier {
 	metrics := &testutils.TestDerivationMetrics{}
-	pipeline := derive.NewDerivationPipeline(log, cfg, l1, eng, metrics)
+	pipeline := derive.NewDerivationPipeline(log, cfg, l1, eng, metrics, syncCfg)
 	pipeline.Reset()
 
 	rollupNode := &L2Verifier{
@@ -139,6 +138,10 @@ func (s *L2Verifier) L2Unsafe() eth.L2BlockRef {
 	return s.derivation.UnsafeL2Head()
 }
 
+func (s *L2Verifier) EngineSyncTarget() eth.L2BlockRef {
+	return s.derivation.EngineSyncTarget()
+}
+
 func (s *L2Verifier) SyncStatus() *eth.SyncStatus {
 	return &eth.SyncStatus{
 		CurrentL1:          s.derivation.Origin(),
@@ -150,6 +153,7 @@ func (s *L2Verifier) SyncStatus() *eth.SyncStatus {
 		SafeL2:             s.L2Safe(),
 		FinalizedL2:        s.L2Finalized(),
 		UnsafeL2SyncTarget: s.derivation.UnsafeL2SyncTarget(),
+		EngineSyncTarget:   s.EngineSyncTarget(),
 	}
 }
 
@@ -206,7 +210,7 @@ func (s *L2Verifier) ActL2PipelineStep(t Testing) {
 
 	s.l2PipelineIdle = false
 	err := s.derivation.Step(t.Ctx())
-	if err == io.EOF {
+	if err == io.EOF || (err != nil && errors.Is(err, derive.EngineP2PSyncing)) {
 		s.l2PipelineIdle = true
 		return
 	} else if err != nil && errors.Is(err, derive.NotEnoughData) {

op-e2e/actions/l2_verifier_test.go

@@ -9,21 +9,22 @@ import (
 
 	"github.com/ethereum-optimism/optimism/op-e2e/e2eutils"
 	"github.com/ethereum-optimism/optimism/op-node/rollup/derive"
+	"github.com/ethereum-optimism/optimism/op-node/rollup/sync"
 	"github.com/ethereum-optimism/optimism/op-node/testlog"
 )
 
-func setupVerifier(t Testing, sd *e2eutils.SetupData, log log.Logger, l1F derive.L1Fetcher) (*L2Engine, *L2Verifier) {
+func setupVerifier(t Testing, sd *e2eutils.SetupData, log log.Logger, l1F derive.L1Fetcher, syncCfg *sync.Config) (*L2Engine, *L2Verifier) {
 	jwtPath := e2eutils.WriteDefaultJWT(t)
 	engine := NewL2Engine(t, log, sd.L2Cfg, sd.RollupCfg.Genesis.L1, jwtPath)
 	engCl := engine.EngineClient(t, sd.RollupCfg)
-	verifier := NewL2Verifier(t, log, l1F, engCl, sd.RollupCfg)
+	verifier := NewL2Verifier(t, log, l1F, engCl, sd.RollupCfg, syncCfg)
 	return engine, verifier
 }
 
 func setupVerifierOnlyTest(t Testing, sd *e2eutils.SetupData, log log.Logger) (*L1Miner, *L2Engine, *L2Verifier) {
 	miner := NewL1Miner(t, log, sd.L1Cfg)
 	l1Cl := miner.L1Client(t, sd.RollupCfg)
-	engine, verifier := setupVerifier(t, sd, log, l1Cl)
+	engine, verifier := setupVerifier(t, sd, log, l1Cl, &sync.Config{})
 	return miner, engine, verifier
 }
 

op-e2e/actions/reorg_test.go

@@ -16,6 +16,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-e2e/e2eutils"
 	"github.com/ethereum-optimism/optimism/op-node/client"
 	"github.com/ethereum-optimism/optimism/op-node/eth"
+	"github.com/ethereum-optimism/optimism/op-node/rollup/sync"
 	"github.com/ethereum-optimism/optimism/op-node/sources"
 	"github.com/ethereum-optimism/optimism/op-node/testlog"
 )
@@ -33,7 +34,7 @@ func setupReorgTestActors(t Testing, dp *e2eutils.DeployParams, sd *e2eutils.Set
 	miner, seqEngine, sequencer := setupSequencerTest(t, sd, log)
 	miner.ActL1SetFeeRecipient(common.Address{'A'})
 	sequencer.ActL2PipelineFull(t)
-	verifEngine, verifier := setupVerifier(t, sd, log, miner.L1Client(t, sd.RollupCfg))
+	verifEngine, verifier := setupVerifier(t, sd, log, miner.L1Client(t, sd.RollupCfg), &sync.Config{})
 	rollupSeqCl := sequencer.RollupClient()
 	batcher := NewL2Batcher(log, sd.RollupCfg, &BatcherCfg{
 		MinL1TxSize: 0,

op-e2e/actions/sync_test.go

@@ -6,6 +6,9 @@ import (
 	"testing"
 
 	"github.com/ethereum-optimism/optimism/op-e2e/e2eutils"
+	"github.com/ethereum-optimism/optimism/op-node/eth"
+	"github.com/ethereum-optimism/optimism/op-node/rollup/sync"
+	"github.com/ethereum-optimism/optimism/op-node/sources"
 	"github.com/ethereum-optimism/optimism/op-node/testlog"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/stretchr/testify/require"
@@ -92,3 +95,74 @@ func TestFinalizeWhileSyncing(gt *testing.T) {
 	// Verify the verifier finalized something new
 	require.Less(t, verifierStartStatus.FinalizedL2.Number, verifier.SyncStatus().FinalizedL2.Number, "verifier finalized L2 blocks during sync")
 }
+
+func TestUnsafeSync(gt *testing.T) {
+	t := NewDefaultTesting(gt)
+	dp := e2eutils.MakeDeployParams(t, defaultRollupTestParams)
+	sd := e2eutils.Setup(t, dp, defaultAlloc)
+	log := testlog.Logger(t, log.LvlInfo)
+
+	sd, _, _, sequencer, seqEng, verifier, _, _ := setupReorgTestActors(t, dp, sd, log)
+	seqEngCl, err := sources.NewEngineClient(seqEng.RPCClient(), log, nil, sources.EngineClientDefaultConfig(sd.RollupCfg))
+	require.NoError(t, err)
+
+	sequencer.ActL2PipelineFull(t)
+	verifier.ActL2PipelineFull(t)
+
+	for i := 0; i < 10; i++ {
+		// Build a L2 block
+		sequencer.ActL2StartBlock(t)
+		sequencer.ActL2EndBlock(t)
+		// Notify new L2 block to verifier by unsafe gossip
+		seqHead, err := seqEngCl.PayloadByLabel(t.Ctx(), eth.Unsafe)
+		require.NoError(t, err)
+		verifier.ActL2UnsafeGossipReceive(seqHead)(t)
+		// Handle unsafe payload
+		verifier.ActL2PipelineFull(t)
+		// Verifier must advance its unsafe head and engine sync target.
+		require.Equal(t, sequencer.L2Unsafe().Hash, verifier.L2Unsafe().Hash)
+		// Check engine sync target updated.
+		require.Equal(t, sequencer.L2Unsafe().Hash, sequencer.EngineSyncTarget().Hash)
+		require.Equal(t, verifier.L2Unsafe().Hash, verifier.EngineSyncTarget().Hash)
+	}
+}
+
+func TestEngineP2PSync(gt *testing.T) {
+	t := NewDefaultTesting(gt)
+	dp := e2eutils.MakeDeployParams(t, defaultRollupTestParams)
+	sd := e2eutils.Setup(t, dp, defaultAlloc)
+	log := testlog.Logger(t, log.LvlInfo)
+
+	miner, seqEng, sequencer := setupSequencerTest(t, sd, log)
+	// Enable engine P2P sync
+	_, verifier := setupVerifier(t, sd, log, miner.L1Client(t, sd.RollupCfg), &sync.Config{EngineSync: true})
+
+	seqEngCl, err := sources.NewEngineClient(seqEng.RPCClient(), log, nil, sources.EngineClientDefaultConfig(sd.RollupCfg))
+	require.NoError(t, err)
+
+	sequencer.ActL2PipelineFull(t)
+	verifier.ActL2PipelineFull(t)
+
+	verifierUnsafeHead := verifier.L2Unsafe()
+
+	// Build a L2 block. This block will not be gossiped to verifier, so verifier can not advance chain by itself.
+	sequencer.ActL2StartBlock(t)
+	sequencer.ActL2EndBlock(t)
+
+	for i := 0; i < 10; i++ {
+		// Build a L2 block
+		sequencer.ActL2StartBlock(t)
+		sequencer.ActL2EndBlock(t)
+		// Notify new L2 block to verifier by unsafe gossip
+		seqHead, err := seqEngCl.PayloadByLabel(t.Ctx(), eth.Unsafe)
+		require.NoError(t, err)
+		verifier.ActL2UnsafeGossipReceive(seqHead)(t)
+		// Handle unsafe payload
+		verifier.ActL2PipelineFull(t)
+		// Verifier must advance only engine sync target.
+		require.NotEqual(t, sequencer.L2Unsafe().Hash, verifier.L2Unsafe().Hash)
+		require.NotEqual(t, verifier.L2Unsafe().Hash, verifier.EngineSyncTarget().Hash)
+		require.Equal(t, verifier.L2Unsafe().Hash, verifierUnsafeHead.Hash)
+		require.Equal(t, sequencer.L2Unsafe().Hash, verifier.EngineSyncTarget().Hash)
+	}
+}

op-e2e/actions/system_config_test.go

@@ -15,6 +15,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-e2e/e2eutils"
 	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum-optimism/optimism/op-node/rollup/derive"
+	"github.com/ethereum-optimism/optimism/op-node/rollup/sync"
 	"github.com/ethereum-optimism/optimism/op-node/testlog"
 )
 
@@ -29,7 +30,7 @@ func TestBatcherKeyRotation(gt *testing.T) {
 	miner, seqEngine, sequencer := setupSequencerTest(t, sd, log)
 	miner.ActL1SetFeeRecipient(common.Address{'A'})
 	sequencer.ActL2PipelineFull(t)
-	_, verifier := setupVerifier(t, sd, log, miner.L1Client(t, sd.RollupCfg))
+	_, verifier := setupVerifier(t, sd, log, miner.L1Client(t, sd.RollupCfg), &sync.Config{})
 	rollupSeqCl := sequencer.RollupClient()
 
 	// the default batcher
@@ -358,7 +359,7 @@ func TestGasLimitChange(gt *testing.T) {
 	miner.ActL1IncludeTx(dp.Addresses.Batcher)(t)
 	miner.ActL1EndBlock(t)
 
-	_, verifier := setupVerifier(t, sd, log, miner.L1Client(t, sd.RollupCfg))
+	_, verifier := setupVerifier(t, sd, log, miner.L1Client(t, sd.RollupCfg), &sync.Config{})
 	verifier.ActL2PipelineFull(t)
 
 	require.Equal(t, sequencer.L2Unsafe(), verifier.L2Safe(), "verifier stays in sync, even with gaslimit changes")

op-e2e/e2eutils/disputegame/deploy.go

@@ -9,6 +9,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-chain-ops/deployer"
 	"github.com/ethereum-optimism/optimism/op-service/client/utils"
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/ethclient"
 	"github.com/stretchr/testify/require"
 )
@@ -50,7 +51,7 @@ func deployDisputeGameContracts(require *require.Assertions, ctx context.Context
 	require.NoError(err)
 
 	// Deploy the fault dispute game implementation
-	_, tx, _, err = bindings.DeployFaultDisputeGame(opts, client, alphabetVMAbsolutePrestateClaim, big.NewInt(alphabetGameDepth), gameDuration, alphaVMAddr)
+	_, tx, _, err = bindings.DeployFaultDisputeGame(opts, client, alphabetVMAbsolutePrestateClaim, big.NewInt(alphabetGameDepth), gameDuration, alphaVMAddr, common.Address{0xBE, 0xEF})
 	require.NoError(err)
 	faultDisputeGameAddr, err := bind.WaitDeployed(ctx, client, tx)
 	require.NoError(err)

op-e2e/system_fpp_test.go

@@ -86,10 +86,7 @@ func testVerifyL2OutputRootEmptyBlock(t *testing.T, detached bool) {
 	require.NoError(t, waitForSafeHead(ctx, receipt.BlockNumber.Uint64(), rollupClient))
 
 	t.Logf("Capture current L2 head as agreed starting point. l2Head=%x l2BlockNumber=%v", receipt.BlockHash, receipt.BlockNumber)
-	agreedL2Output, err := rollupClient.OutputAtBlock(ctx, receipt.BlockNumber.Uint64())
-	require.NoError(t, err, "could not retrieve l2 agreed block")
-	l2Head := agreedL2Output.BlockRef.Hash
-	l2OutputRoot := agreedL2Output.OutputRoot
+	l2Head := receipt.BlockHash
 
 	t.Log("=====Stopping batch submitter=====")
 	err = sys.BatchSubmitter.Stop(ctx)
@@ -139,7 +136,6 @@ func testVerifyL2OutputRootEmptyBlock(t *testing.T, detached bool) {
 	testFaultProofProgramScenario(t, ctx, sys, &FaultProofProgramTestScenario{
 		L1Head:             l1Head,
 		L2Head:             l2Head,
-		L2OutputRoot:       common.Hash(l2OutputRoot),
 		L2Claim:            common.Hash(l2Claim),
 		L2ClaimBlockNumber: l2ClaimBlockNumber,
 		Detached:           detached,
@@ -185,12 +181,9 @@ func testVerifyL2OutputRoot(t *testing.T, detached bool) {
 	})
 
 	t.Log("Capture current L2 head as agreed starting point")
-	latestBlock, err := l2Seq.BlockByNumber(ctx, nil)
-	require.NoError(t, err)
-	agreedL2Output, err := rollupClient.OutputAtBlock(ctx, latestBlock.NumberU64())
+	l2AgreedBlock, err := l2Seq.BlockByNumber(ctx, nil)
 	require.NoError(t, err, "could not retrieve l2 agreed block")
-	l2Head := agreedL2Output.BlockRef.Hash
-	l2OutputRoot := agreedL2Output.OutputRoot
+	l2Head := l2AgreedBlock.Hash()
 
 	t.Log("Sending transactions to modify existing state, within challenged period")
 	SendDepositTx(t, cfg, l1Client, l2Seq, opts, func(l2Opts *DepositTxOpts) {
@@ -221,7 +214,6 @@ func testVerifyL2OutputRoot(t *testing.T, detached bool) {
 	testFaultProofProgramScenario(t, ctx, sys, &FaultProofProgramTestScenario{
 		L1Head:             l1Head,
 		L2Head:             l2Head,
-		L2OutputRoot:       common.Hash(l2OutputRoot),
 		L2Claim:            common.Hash(l2Claim),
 		L2ClaimBlockNumber: l2ClaimBlockNumber,
 		Detached:           detached,
@@ -231,7 +223,6 @@ func testVerifyL2OutputRoot(t *testing.T, detached bool) {
 type FaultProofProgramTestScenario struct {
 	L1Head             common.Hash
 	L2Head             common.Hash
-	L2OutputRoot       common.Hash
 	L2Claim            common.Hash
 	L2ClaimBlockNumber uint64
 	Detached           bool
@@ -240,7 +231,7 @@ type FaultProofProgramTestScenario struct {
 // testFaultProofProgramScenario runs the fault proof program in several contexts, given a test scenario.
 func testFaultProofProgramScenario(t *testing.T, ctx context.Context, sys *System, s *FaultProofProgramTestScenario) {
 	preimageDir := t.TempDir()
-	fppConfig := oppconf.NewConfig(sys.RollupConfig, sys.L2GenesisCfg.Config, s.L1Head, s.L2Head, s.L2OutputRoot, common.Hash(s.L2Claim), s.L2ClaimBlockNumber)
+	fppConfig := oppconf.NewConfig(sys.RollupConfig, sys.L2GenesisCfg.Config, s.L1Head, s.L2Head, common.Hash(s.L2Claim), s.L2ClaimBlockNumber)
 	fppConfig.L1URL = sys.NodeEndpoint("l1")
 	fppConfig.L2URL = sys.NodeEndpoint("sequencer")
 	fppConfig.DataDir = preimageDir

op-node/eth/output.go

 package eth
 
 import (
-	"errors"
-
 	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/crypto"
 )
 
 type OutputResponse struct {
@@ -15,70 +12,3 @@ type OutputResponse struct {
 	StateRoot             common.Hash `json:"stateRoot"`
 	Status                *SyncStatus `json:"syncStatus"`
 }
-
-var (
-	ErrInvalidOutput        = errors.New("invalid output")
-	ErrInvalidOutputVersion = errors.New("invalid output version")
-
-	OutputVersionV0 = Bytes32{}
-)
-
-type Output interface {
-	// Version returns the version of the L2 output
-	Version() Bytes32
-
-	// Marshal a L2 output into a byte slice for hashing
-	Marshal() []byte
-}
-
-type OutputV0 struct {
-	StateRoot                Bytes32
-	MessagePasserStorageRoot Bytes32
-	BlockHash                common.Hash
-}
-
-func (o *OutputV0) Version() Bytes32 {
-	return OutputVersionV0
-}
-
-func (o *OutputV0) Marshal() []byte {
-	var buf [128]byte
-	version := o.Version()
-	copy(buf[:32], version[:])
-	copy(buf[32:], o.StateRoot[:])
-	copy(buf[64:], o.MessagePasserStorageRoot[:])
-	copy(buf[96:], o.BlockHash[:])
-	return buf[:]
-}
-
-// OutputRoot returns the keccak256 hash of the marshaled L2 output
-func OutputRoot(output Output) Bytes32 {
-	marshaled := output.Marshal()
-	return Bytes32(crypto.Keccak256Hash(marshaled))
-}
-
-func UnmarshalOutput(data []byte) (Output, error) {
-	if len(data) < 32 {
-		return nil, ErrInvalidOutput
-	}
-	var ver Bytes32
-	copy(ver[:], data[:32])
-	switch ver {
-	case OutputVersionV0:
-		return unmarshalOutputV0(data)
-	default:
-		return nil, ErrInvalidOutputVersion
-	}
-}
-
-func unmarshalOutputV0(data []byte) (*OutputV0, error) {
-	if len(data) != 128 {
-		return nil, ErrInvalidOutput
-	}
-	var output OutputV0
-	// data[:32] is the version
-	copy(output.StateRoot[:], data[32:64])
-	copy(output.MessagePasserStorageRoot[:], data[64:96])
-	copy(output.BlockHash[:], data[96:128])
-	return &output, nil
-}

op-node/eth/output_test.go

-package eth
-
-import (
-	"testing"
-
-	"github.com/ethereum/go-ethereum/common"
-	"github.com/stretchr/testify/require"
-)
-
-func TestOutputV0Codec(t *testing.T) {
-	output := OutputV0{
-		StateRoot:                Bytes32{1, 2, 3},
-		MessagePasserStorageRoot: Bytes32{4, 5, 6},
-		BlockHash:                common.Hash{7, 8, 9},
-	}
-	marshaled := output.Marshal()
-	unmarshaled, err := UnmarshalOutput(marshaled)
-	require.NoError(t, err)
-	unmarshaledV0 := unmarshaled.(*OutputV0)
-	require.Equal(t, output, *unmarshaledV0)
-
-	_, err = UnmarshalOutput([]byte{0: 0xA, 32: 0xA})
-	require.ErrorIs(t, err, ErrInvalidOutputVersion)
-	_, err = UnmarshalOutput([]byte{64: 0xA})
-	require.ErrorIs(t, err, ErrInvalidOutput)
-}

op-node/eth/sync_status.go

@@ -35,4 +35,7 @@ type SyncStatus struct {
 	// UnsafeL2SyncTarget points to the first unprocessed unsafe L2 block.
 	// It may be zeroed if there is no targeted block.
 	UnsafeL2SyncTarget L2BlockRef `json:"queued_unsafe_l2"`
+	// EngineSyncTarget points to the L2 block that the execution engine is syncing to.
+	// If it is ahead from UnsafeL2, the engine is in progress of P2P sync.
+	EngineSyncTarget L2BlockRef `json:"engine_sync_target"`
 }

op-node/flags/flags.go

@@ -214,6 +214,21 @@ var (
 		EnvVars:  prefixEnvVars("L2_BACKUP_UNSAFE_SYNC_RPC_TRUST_RPC"),
 		Required: false,
 	}
+	L2EngineSyncEnabled = &cli.BoolFlag{
+		Name:     "l2.engine-sync",
+		Usage:    "Enables or disables execution engine P2P sync",
+		EnvVars:  prefixEnvVars("L2_ENGINE_SYNC_ENABLED"),
+		Required: false,
+		Value:    false,
+	}
+	SkipSyncStartCheck = &cli.BoolFlag{
+		Name: "l2.skip-sync-start-check",
+		Usage: "Skip sanity check of consistency of L1 origins of the unsafe L2 blocks when determining the sync-starting point. " +
+			"This defers the L1-origin verification, and is recommended to use in when utilizing l2.engine-sync",
+		EnvVars:  prefixEnvVars("L2_SKIP_SYNC_START_CHECK"),
+		Required: false,
+		Value:    false,
+	}
 )
 
 var requiredFlags = []cli.Flag{
@@ -252,6 +267,8 @@ var optionalFlags = []cli.Flag{
 	HeartbeatURLFlag,
 	BackupL2UnsafeSyncRPC,
 	BackupL2UnsafeSyncRPCTrustRPC,
+	L2EngineSyncEnabled,
+	SkipSyncStartCheck,
 }
 
 // Flags contains the list of configuration options available to the binary.

op-node/flags/p2p_flags.go

@@ -30,6 +30,7 @@ var (
 		Name:     "p2p.scoring",
 		Usage:    "Sets the peer scoring strategy for the P2P stack. Can be one of: none or light.",
 		Required: false,
+		Value:    "light",
 		EnvVars:  p2pEnv("PEER_SCORING"),
 	}
 	PeerScoring = &cli.StringFlag{

op-node/node/api.go

@@ -4,10 +4,12 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/log"
 
+	"github.com/ethereum-optimism/optimism/op-bindings/predeploys"
 	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum-optimism/optimism/op-node/rollup"
 	"github.com/ethereum-optimism/optimism/op-node/version"
@@ -18,7 +20,6 @@ type l2EthClient interface {
 	// GetProof returns a proof of the account, it may return a nil result without error if the address was not found.
 	// Optionally keys of the account storage trie can be specified to include with corresponding values in the proof.
 	GetProof(ctx context.Context, address common.Address, storage []common.Hash, blockTag string) (*eth.AccountResult, error)
-	OutputV0AtBlock(ctx context.Context, blockHash common.Hash) (*eth.OutputV0, error)
 }
 
 type driverClient interface {
@@ -98,16 +99,40 @@ func (n *nodeAPI) OutputAtBlock(ctx context.Context, number hexutil.Uint64) (*et
 		return nil, fmt.Errorf("failed to get L2 block ref with sync status: %w", err)
 	}
 
-	output, err := n.client.OutputV0AtBlock(ctx, ref.Hash)
+	head, err := n.client.InfoByHash(ctx, ref.Hash)
 	if err != nil {
-		return nil, fmt.Errorf("failed to get L2 output at block %s: %w", ref, err)
+		return nil, fmt.Errorf("failed to get L2 block by hash %s: %w", ref, err)
 	}
+	if head == nil {
+		return nil, ethereum.NotFound
+	}
+
+	proof, err := n.client.GetProof(ctx, predeploys.L2ToL1MessagePasserAddr, []common.Hash{}, ref.Hash.String())
+	if err != nil {
+		return nil, fmt.Errorf("failed to get contract proof at block %s: %w", ref, err)
+	}
+	if proof == nil {
+		return nil, fmt.Errorf("proof %w", ethereum.NotFound)
+	}
+	// make sure that the proof (including storage hash) that we retrieved is correct by verifying it against the state-root
+	if err := proof.Verify(head.Root()); err != nil {
+		n.log.Error("invalid withdrawal root detected in block", "stateRoot", head.Root(), "blocknum", number, "msg", err)
+		return nil, fmt.Errorf("invalid withdrawal root hash, state root was %s: %w", head.Root(), err)
+	}
+
+	var l2OutputRootVersion eth.Bytes32 // it's zero for now
+	l2OutputRoot, err := rollup.ComputeL2OutputRootV0(head, proof.StorageHash)
+	if err != nil {
+		n.log.Error("Error computing L2 output root, nil ptr passed to hashing function")
+		return nil, err
+	}
+
 	return &eth.OutputResponse{
-		Version:               output.Version(),
-		OutputRoot:            eth.OutputRoot(output),
+		Version:               l2OutputRootVersion,
+		OutputRoot:            l2OutputRoot,
 		BlockRef:              ref,
-		WithdrawalStorageRoot: common.Hash(output.MessagePasserStorageRoot),
-		StateRoot:             common.Hash(output.StateRoot),
+		WithdrawalStorageRoot: proof.StorageHash,
+		StateRoot:             head.Root(),
 		Status:                status,
 	}, nil
 }

op-node/node/config.go

@@ -10,6 +10,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-node/p2p"
 	"github.com/ethereum-optimism/optimism/op-node/rollup"
 	"github.com/ethereum-optimism/optimism/op-node/rollup/driver"
+	"github.com/ethereum-optimism/optimism/op-node/rollup/sync"
 	oppprof "github.com/ethereum-optimism/optimism/op-service/pprof"
 	"github.com/ethereum/go-ethereum/log"
 )
@@ -43,6 +44,8 @@ type Config struct {
 	// Optional
 	Tracer    Tracer
 	Heartbeat HeartbeatConfig
+
+	Sync sync.Config
 }
 
 type RPCConfig struct {

op-node/node/node.go

@@ -199,7 +199,7 @@ func (n *OpNode) initL2(ctx context.Context, cfg *Config, snapshotLog log.Logger
 		return err
 	}
 
-	n.l2Driver = driver.NewDriver(&cfg.Driver, &cfg.Rollup, n.l2Source, n.l1Source, n, n, n.log, snapshotLog, n.metrics, cfg.ConfigPersistence)
+	n.l2Driver = driver.NewDriver(&cfg.Driver, &cfg.Rollup, n.l2Source, n.l1Source, n, n, n.log, snapshotLog, n.metrics, cfg.ConfigPersistence, &cfg.Sync)
 
 	return nil
 }

op-node/node/server_test.go

@@ -16,6 +16,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/log"
 
+	"github.com/ethereum-optimism/optimism/op-bindings/predeploys"
 	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum-optimism/optimism/op-node/metrics"
 	"github.com/ethereum-optimism/optimism/op-node/rollup"
@@ -83,6 +84,17 @@ func TestOutputAtBlock(t *testing.T) {
 	}
 
 	l2Client := &testutils.MockL2Client{}
+	info := &testutils.MockBlockInfo{
+		InfoHash:        header.Hash(),
+		InfoParentHash:  header.ParentHash,
+		InfoCoinbase:    header.Coinbase,
+		InfoRoot:        header.Root,
+		InfoNum:         header.Number.Uint64(),
+		InfoTime:        header.Time,
+		InfoMixDigest:   header.MixDigest,
+		InfoBaseFee:     header.BaseFee,
+		InfoReceiptRoot: header.ReceiptHash,
+	}
 	ref := eth.L2BlockRef{
 		Hash:           header.Hash(),
 		Number:         header.Number.Uint64(),
@@ -91,12 +103,8 @@ func TestOutputAtBlock(t *testing.T) {
 		L1Origin:       eth.BlockID{},
 		SequenceNumber: 0,
 	}
-	output := &eth.OutputV0{
-		StateRoot:                eth.Bytes32(header.Root),
-		BlockHash:                ref.Hash,
-		MessagePasserStorageRoot: eth.Bytes32(result.StorageHash),
-	}
-	l2Client.ExpectOutputV0AtBlock(common.HexToHash("0x8512bee03061475e4b069171f7b406097184f16b22c3f5c97c0abfc49591c524"), output, nil)
+	l2Client.ExpectInfoByHash(common.HexToHash("0x8512bee03061475e4b069171f7b406097184f16b22c3f5c97c0abfc49591c524"), info, nil)
+	l2Client.ExpectGetProof(predeploys.L2ToL1MessagePasserAddr, []common.Hash{}, "0x8512bee03061475e4b069171f7b406097184f16b22c3f5c97c0abfc49591c524", &result, nil)
 
 	drClient := &mockDriverClient{}
 	status := randomSyncStatus(rand.New(rand.NewSource(123)))
@@ -159,6 +167,7 @@ func randomSyncStatus(rng *rand.Rand) *eth.SyncStatus {
 		SafeL2:             testutils.RandomL2BlockRef(rng),
 		FinalizedL2:        testutils.RandomL2BlockRef(rng),
 		UnsafeL2SyncTarget: testutils.RandomL2BlockRef(rng),
+		EngineSyncTarget:   testutils.RandomL2BlockRef(rng),
 	}
 }
 

op-node/rollup/derive/engine_queue_test.go

@@ -17,6 +17,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum-optimism/optimism/op-node/metrics"
 	"github.com/ethereum-optimism/optimism/op-node/rollup"
+	"github.com/ethereum-optimism/optimism/op-node/rollup/sync"
 	"github.com/ethereum-optimism/optimism/op-node/testlog"
 	"github.com/ethereum-optimism/optimism/op-node/testutils"
 )
@@ -246,7 +247,7 @@ func TestEngineQueue_Finalize(t *testing.T) {
 
 	prev := &fakeAttributesQueue{}
 
-	eq := NewEngineQueue(logger, cfg, eng, metrics, prev, l1F)
+	eq := NewEngineQueue(logger, cfg, eng, metrics, prev, l1F, &sync.Config{})
 	require.ErrorIs(t, eq.Reset(context.Background(), eth.L1BlockRef{}, eth.SystemConfig{}), io.EOF)
 
 	require.Equal(t, refB1, eq.SafeL2Head(), "L2 reset should go back to sequence window ago: blocks with origin E and D are not safe until we reconcile, C is extra, and B1 is the end we look for")
@@ -480,7 +481,7 @@ func TestEngineQueue_ResetWhenUnsafeOriginNotCanonical(t *testing.T) {
 
 	prev := &fakeAttributesQueue{origin: refE}
 
-	eq := NewEngineQueue(logger, cfg, eng, metrics, prev, l1F)
+	eq := NewEngineQueue(logger, cfg, eng, metrics, prev, l1F, &sync.Config{})
 	require.ErrorIs(t, eq.Reset(context.Background(), eth.L1BlockRef{}, eth.SystemConfig{}), io.EOF)
 
 	require.Equal(t, refB1, eq.SafeL2Head(), "L2 reset should go back to sequence window ago: blocks with origin E and D are not safe until we reconcile, C is extra, and B1 is the end we look for")
@@ -811,7 +812,7 @@ func TestVerifyNewL1Origin(t *testing.T) {
 			}, nil)
 
 			prev := &fakeAttributesQueue{origin: refE}
-			eq := NewEngineQueue(logger, cfg, eng, metrics, prev, l1F)
+			eq := NewEngineQueue(logger, cfg, eng, metrics, prev, l1F, &sync.Config{})
 			require.ErrorIs(t, eq.Reset(context.Background(), eth.L1BlockRef{}, eth.SystemConfig{}), io.EOF)
 
 			require.Equal(t, refB1, eq.SafeL2Head(), "L2 reset should go back to sequence window ago: blocks with origin E and D are not safe until we reconcile, C is extra, and B1 is the end we look for")
@@ -909,7 +910,7 @@ func TestBlockBuildingRace(t *testing.T) {
 	}
 
 	prev := &fakeAttributesQueue{origin: refA, attrs: attrs}
-	eq := NewEngineQueue(logger, cfg, eng, metrics, prev, l1F)
+	eq := NewEngineQueue(logger, cfg, eng, metrics, prev, l1F, &sync.Config{})
 	require.ErrorIs(t, eq.Reset(context.Background(), eth.L1BlockRef{}, eth.SystemConfig{}), io.EOF)
 
 	id := eth.PayloadID{0xff}
@@ -1079,8 +1080,9 @@ func TestResetLoop(t *testing.T) {
 
 	prev := &fakeAttributesQueue{origin: refA, attrs: attrs}
 
-	eq := NewEngineQueue(logger, cfg, eng, metrics.NoopMetrics, prev, l1F)
+	eq := NewEngineQueue(logger, cfg, eng, metrics.NoopMetrics, prev, l1F, &sync.Config{})
 	eq.unsafeHead = refA2
+	eq.engineSyncTarget = refA2
 	eq.safeHead = refA1
 	eq.finalized = refA0
 
@@ -1176,7 +1178,7 @@ func TestEngineQueue_StepPopOlderUnsafe(t *testing.T) {
 
 	prev := &fakeAttributesQueue{origin: refA}
 
-	eq := NewEngineQueue(logger, cfg, eng, metrics.NoopMetrics, prev, l1F)
+	eq := NewEngineQueue(logger, cfg, eng, metrics.NoopMetrics, prev, l1F, &sync.Config{})
 	eq.unsafeHead = refA2
 	eq.safeHead = refA0
 	eq.finalized = refA0

op-node/rollup/derive/error.go

@@ -96,3 +96,6 @@ var ErrCritical = NewCriticalError(nil)
 // NotEnoughData implies that the function currently does not have enough data to progress
 // but if it is retried enough times, it will eventually return a real value or io.EOF
 var NotEnoughData = errors.New("not enough data")
+
+// EngineP2PSyncing implies that the execution engine is currently in progress of P2P sync.
+var EngineP2PSyncing = errors.New("engine is P2P syncing")

op-node/rollup/derive/pipeline.go

@@ -2,6 +2,7 @@ package derive
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"io"
 
@@ -9,6 +10,7 @@ import (
 
 	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum-optimism/optimism/op-node/rollup"
+	"github.com/ethereum-optimism/optimism/op-node/rollup/sync"
 )
 
 type Metrics interface {
@@ -46,6 +48,7 @@ type EngineQueueStage interface {
 	Finalized() eth.L2BlockRef
 	UnsafeL2Head() eth.L2BlockRef
 	SafeL2Head() eth.L2BlockRef
+	EngineSyncTarget() eth.L2BlockRef
 	Origin() eth.L1BlockRef
 	SystemConfig() eth.SystemConfig
 	SetUnsafeHead(head eth.L2BlockRef)
@@ -75,7 +78,7 @@ type DerivationPipeline struct {
 }
 
 // NewDerivationPipeline creates a derivation pipeline, which should be reset before use.
-func NewDerivationPipeline(log log.Logger, cfg *rollup.Config, l1Fetcher L1Fetcher, engine Engine, metrics Metrics) *DerivationPipeline {
+func NewDerivationPipeline(log log.Logger, cfg *rollup.Config, l1Fetcher L1Fetcher, engine Engine, metrics Metrics, syncCfg *sync.Config) *DerivationPipeline {
 
 	// Pull stages
 	l1Traversal := NewL1Traversal(log, cfg, l1Fetcher)
@@ -89,7 +92,7 @@ func NewDerivationPipeline(log log.Logger, cfg *rollup.Config, l1Fetcher L1Fetch
 	attributesQueue := NewAttributesQueue(log, cfg, attrBuilder, batchQueue)
 
 	// Step stages
-	eng := NewEngineQueue(log, cfg, engine, metrics, attributesQueue, l1Fetcher)
+	eng := NewEngineQueue(log, cfg, engine, metrics, attributesQueue, l1Fetcher, syncCfg)
 
 	// Reset from engine queue then up from L1 Traversal. The stages do not talk to each other during
 	// the reset, but after the engine queue, this is the order in which the stages could talk to each other.
@@ -147,6 +150,10 @@ func (dp *DerivationPipeline) UnsafeL2Head() eth.L2BlockRef {
 	return dp.eng.UnsafeL2Head()
 }
 
+func (dp *DerivationPipeline) EngineSyncTarget() eth.L2BlockRef {
+	return dp.eng.EngineSyncTarget()
+}
+
 func (dp *DerivationPipeline) StartPayload(ctx context.Context, parent eth.L2BlockRef, attrs *eth.PayloadAttributes, updateSafe bool) (errType BlockInsertionErrType, err error) {
 	return dp.eng.StartPayload(ctx, parent, attrs, updateSafe)
 }
@@ -199,6 +206,8 @@ func (dp *DerivationPipeline) Step(ctx context.Context) error {
 	if err := dp.eng.Step(ctx); err == io.EOF {
 		// If every stage has returned io.EOF, try to advance the L1 Origin
 		return dp.traversal.AdvanceL1Block(ctx)
+	} else if errors.Is(err, EngineP2PSyncing) {
+		return err
 	} else if err != nil {
 		return fmt.Errorf("engine stage failed: %w", err)
 	} else {

op-node/rollup/driver/driver.go

@@ -10,6 +10,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum-optimism/optimism/op-node/rollup"
 	"github.com/ethereum-optimism/optimism/op-node/rollup/derive"
+	"github.com/ethereum-optimism/optimism/op-node/rollup/sync"
 )
 
 type Metrics interface {
@@ -58,6 +59,7 @@ type DerivationPipeline interface {
 	UnsafeL2Head() eth.L2BlockRef
 	Origin() eth.L1BlockRef
 	EngineReady() bool
+	EngineSyncTarget() eth.L2BlockRef
 }
 
 type L1StateIface interface {
@@ -108,13 +110,13 @@ type SequencerStateListener interface {
 }
 
 // NewDriver composes an events handler that tracks L1 state, triggers L2 derivation, and optionally sequences new L2 blocks.
-func NewDriver(driverCfg *Config, cfg *rollup.Config, l2 L2Chain, l1 L1Chain, altSync AltSync, network Network, log log.Logger, snapshotLog log.Logger, metrics Metrics, sequencerStateListener SequencerStateListener) *Driver {
+func NewDriver(driverCfg *Config, cfg *rollup.Config, l2 L2Chain, l1 L1Chain, altSync AltSync, network Network, log log.Logger, snapshotLog log.Logger, metrics Metrics, sequencerStateListener SequencerStateListener, syncCfg *sync.Config) *Driver {
 	l1 = NewMeteredL1Fetcher(l1, metrics)
 	l1State := NewL1State(log, metrics)
 	sequencerConfDepth := NewConfDepth(driverCfg.SequencerConfDepth, l1State.L1Head, l1)
 	findL1Origin := NewL1OriginSelector(log, cfg, sequencerConfDepth)
 	verifConfDepth := NewConfDepth(driverCfg.VerifierConfDepth, l1State.L1Head, l1)
-	derivationPipeline := derive.NewDerivationPipeline(log, cfg, verifConfDepth, l2, metrics)
+	derivationPipeline := derive.NewDerivationPipeline(log, cfg, verifConfDepth, l2, metrics, syncCfg)
 	attrBuilder := derive.NewFetchingAttributesBuilder(cfg, l1, l2)
 	engine := derivationPipeline
 	meteredEngine := NewMeteredEngine(cfg, engine, metrics, log)

op-node/rollup/driver/state.go

@@ -314,7 +314,12 @@ func (s *Driver) eventLoop() {
 			err := s.derivation.Step(context.Background())
 			stepAttempts += 1 // count as attempt by default. We reset to 0 if we are making healthy progress.
 			if err == io.EOF {
-				s.log.Debug("Derivation process went idle", "progress", s.derivation.Origin())
+				s.log.Debug("Derivation process went idle", "progress", s.derivation.Origin(), "err", err)
+				stepAttempts = 0
+				s.metrics.SetDerivationIdle(true)
+				continue
+			} else if err != nil && errors.Is(err, derive.EngineP2PSyncing) {
+				s.log.Debug("Derivation process went idle because the engine is syncing", "progress", s.derivation.Origin(), "sync_target", s.derivation.EngineSyncTarget(), "err", err)
 				stepAttempts = 0
 				s.metrics.SetDerivationIdle(true)
 				continue
@@ -474,6 +479,7 @@ func (s *Driver) syncStatus() *eth.SyncStatus {
 		SafeL2:             s.derivation.SafeL2Head(),
 		FinalizedL2:        s.derivation.Finalized(),
 		UnsafeL2SyncTarget: s.derivation.UnsafeL2SyncTarget(),
+		EngineSyncTarget:   s.derivation.EngineSyncTarget(),
 	}
 }
 

op-node/rollup/output_root.go

@@ -5,33 +5,32 @@ import (
 
 	"github.com/ethereum-optimism/optimism/op-bindings/bindings"
 	"github.com/ethereum-optimism/optimism/op-node/eth"
+	"github.com/ethereum/go-ethereum/crypto"
 )
 
-var ErrNilProof = errors.New("output root proof is nil")
+var NilProof = errors.New("Output root proof is nil")
 
 // ComputeL2OutputRoot computes the L2 output root by hashing an output root proof.
 func ComputeL2OutputRoot(proofElements *bindings.TypesOutputRootProof) (eth.Bytes32, error) {
 	if proofElements == nil {
-		return eth.Bytes32{}, ErrNilProof
+		return eth.Bytes32{}, NilProof
 	}
 
-	if proofElements.Version != [32]byte{} {
-		return eth.Bytes32{}, errors.New("unsupported output root version")
-	}
-	l2Output := eth.OutputV0{
-		StateRoot:                eth.Bytes32(proofElements.StateRoot),
-		MessagePasserStorageRoot: proofElements.MessagePasserStorageRoot,
-		BlockHash:                proofElements.LatestBlockhash,
-	}
-	return eth.OutputRoot(&l2Output), nil
+	digest := crypto.Keccak256Hash(
+		proofElements.Version[:],
+		proofElements.StateRoot[:],
+		proofElements.MessagePasserStorageRoot[:],
+		proofElements.LatestBlockhash[:],
+	)
+	return eth.Bytes32(digest), nil
 }
 
 func ComputeL2OutputRootV0(block eth.BlockInfo, storageRoot [32]byte) (eth.Bytes32, error) {
-	stateRoot := block.Root()
-	l2Output := eth.OutputV0{
-		StateRoot:                eth.Bytes32(stateRoot),
+	var l2OutputRootVersion eth.Bytes32 // it's zero for now
+	return ComputeL2OutputRoot(&bindings.TypesOutputRootProof{
+		Version:                  l2OutputRootVersion,
+		StateRoot:                block.Root(),
 		MessagePasserStorageRoot: storageRoot,
-		BlockHash:                block.Hash(),
-	}
-	return eth.OutputRoot(&l2Output), nil
+		LatestBlockhash:          block.Hash(),
+	})
 }

op-node/rollup/sync/config.go

+package sync
+
+type Config struct {
+	// EngineSync is true when the EngineQueue can trigger execution engine P2P sync.
+	EngineSync bool `json:"engine_sync"`
+	// SkipSyncStartCheck skip the sanity check of consistency of L1 origins of the unsafe L2 blocks when determining the sync-starting point. This defers the L1-origin verification, and is recommended to use in when utilizing l2.engine-sync
+	SkipSyncStartCheck bool `json:"skip_sync_start_check"`
+}

op-node/rollup/sync/start.go

@@ -102,7 +102,7 @@ func currentHeads(ctx context.Context, cfg *rollup.Config, l2 L2Chain) (*FindHea
 // Plausible: meaning that the blockhash of the L2 block's L1 origin
 // (as reported in the L1 Attributes deposit within the L2 block) is not canonical at another height in the L1 chain,
 // and the same holds for all its ancestors.
-func FindL2Heads(ctx context.Context, cfg *rollup.Config, l1 L1Chain, l2 L2Chain, lgr log.Logger) (result *FindHeadsResult, err error) {
+func FindL2Heads(ctx context.Context, cfg *rollup.Config, l1 L1Chain, l2 L2Chain, lgr log.Logger, syncCfg *Config) (result *FindHeadsResult, err error) {
 	// Fetch current L2 forkchoice state
 	result, err = currentHeads(ctx, cfg, l2)
 	if err != nil {
@@ -170,6 +170,10 @@ func FindL2Heads(ctx context.Context, cfg *rollup.Config, l1 L1Chain, l2 L2Chain
 		if (n.Number == result.Finalized.Number) && (n.Hash != result.Finalized.Hash) {
 			return nil, fmt.Errorf("%w: finalized %s, got: %s", ReorgFinalizedErr, result.Finalized, n)
 		}
+
+		// If we don't have a usable unsafe head, then set it
+		if result.Unsafe == (eth.L2BlockRef{}) {
+			result.Unsafe = n
 			// Check we are not reorging L2 incredibly deep
 			if n.L1Origin.Number+(MaxReorgSeqWindows*cfg.SeqWindowSize) < prevUnsafe.L1Origin.Number {
 				// If the reorg depth is too large, something is fishy.
@@ -178,10 +182,6 @@ func FindL2Heads(ctx context.Context, cfg *rollup.Config, l1 L1Chain, l2 L2Chain
 				// stopgap solution.
 				return nil, fmt.Errorf("%w: traversed back to L2 block %s, but too deep compared to previous unsafe block %s", TooDeepReorgErr, n, prevUnsafe)
 			}
-
-		// If we don't have a usable unsafe head, then set it
-		if result.Unsafe == (eth.L2BlockRef{}) {
-			result.Unsafe = n
 		}
 
 		if ahead {
@@ -212,6 +212,11 @@ func FindL2Heads(ctx context.Context, cfg *rollup.Config, l1 L1Chain, l2 L2Chain
 			return result, nil
 		}
 
+		if syncCfg.SkipSyncStartCheck && highestL2WithCanonicalL1Origin.Hash == n.Hash {
+			lgr.Info("Found highest L2 block with canonical L1 origin. Skip further sanity check and jump to the safe head")
+			n = result.Safe
+			continue
+		}
 		// Pull L2 parent for next iteration
 		parent, err := l2.L2BlockRefByHash(ctx, n.ParentHash)
 		if err != nil {

op-node/rollup/sync/start_test.go

@@ -76,7 +76,7 @@ func (c *syncStartTestCase) Run(t *testing.T) {
 	}
 	lgr := log.New()
 	lgr.SetHandler(log.DiscardHandler())
-	result, err := FindL2Heads(context.Background(), cfg, chain, chain, lgr)
+	result, err := FindL2Heads(context.Background(), cfg, chain, chain, lgr, &Config{})
 	if c.ExpectedErr != nil {
 		require.ErrorIs(t, err, c.ExpectedErr, "expected error")
 		return
@@ -286,6 +286,37 @@ func TestFindSyncStart(t *testing.T) {
 			SafeL2Head:     'D',
 			ExpectedErr:    WrongChainErr,
 		},
+		{
+			// FindL2Heads() keeps walking back to safe head after finding canonical unsafe head
+			// TooDeepReorgErr must not be raised
+			Name:           "long traverse to safe head",
+			GenesisL1Num:   0,
+			L1:             "abcdefgh",
+			L2:             "ABCDEFGH",
+			NewL1:          "abcdefgx",
+			PreFinalizedL2: 'B',
+			PreSafeL2:      'B',
+			GenesisL1:      'a',
+			GenesisL2:      'A',
+			UnsafeL2Head:   'G',
+			SeqWindowSize:  1,
+			SafeL2Head:     'B',
+			ExpectedErr:    nil,
+		},
+		{
+			// L2 reorg is too deep
+			Name:           "reorg too deep",
+			GenesisL1Num:   0,
+			L1:             "abcdefgh",
+			L2:             "ABCDEFGH",
+			NewL1:          "abijklmn",
+			PreFinalizedL2: 'B',
+			PreSafeL2:      'B',
+			GenesisL1:      'a',
+			GenesisL2:      'A',
+			SeqWindowSize:  1,
+			ExpectedErr:    TooDeepReorgErr,
+		},
 	}
 
 	for _, testCase := range testCases {

op-node/service.go

@@ -22,6 +22,7 @@ import (
 	p2pcli "github.com/ethereum-optimism/optimism/op-node/p2p/cli"
 	"github.com/ethereum-optimism/optimism/op-node/rollup"
 	"github.com/ethereum-optimism/optimism/op-node/rollup/driver"
+	"github.com/ethereum-optimism/optimism/op-node/rollup/sync"
 )
 
 // NewConfig creates a Config from the provided flags or environment variables.
@@ -58,6 +59,8 @@ func NewConfig(ctx *cli.Context, log log.Logger) (*node.Config, error) {
 
 	l2SyncEndpoint := NewL2SyncEndpointConfig(ctx)
 
+	syncConfig := NewSyncConfig(ctx)
+
 	cfg := &node.Config{
 		L1:     l1Endpoint,
 		L2:     l2Endpoint,
@@ -88,6 +91,7 @@ func NewConfig(ctx *cli.Context, log log.Logger) (*node.Config, error) {
 			URL:     ctx.String(flags.HeartbeatURLFlag.Name),
 		},
 		ConfigPersistence: configPersistence,
+		Sync:              *syncConfig,
 	}
 
 	if err := cfg.LoadPersisted(log); err != nil {
@@ -214,3 +218,10 @@ func NewSnapshotLogger(ctx *cli.Context) (log.Logger, error) {
 	logger.SetHandler(handler)
 	return logger, nil
 }
+
+func NewSyncConfig(ctx *cli.Context) *sync.Config {
+	return &sync.Config{
+		EngineSync:         ctx.Bool(flags.L2EngineSyncEnabled.Name),
+		SkipSyncStartCheck: ctx.Bool(flags.SkipSyncStartCheck.Name),
+	}
+}

op-node/sources/l2_client.go

@@ -10,7 +10,6 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/log"
 
-	"github.com/ethereum-optimism/optimism/op-bindings/predeploys"
 	"github.com/ethereum-optimism/optimism/op-node/client"
 	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum-optimism/optimism/op-node/rollup"
@@ -166,31 +165,3 @@ func (s *L2Client) SystemConfigByL2Hash(ctx context.Context, hash common.Hash) (
 	s.systemConfigsCache.Add(hash, cfg)
 	return cfg, nil
 }
-
-func (s *L2Client) OutputV0AtBlock(ctx context.Context, blockHash common.Hash) (*eth.OutputV0, error) {
-	head, err := s.InfoByHash(ctx, blockHash)
-	if err != nil {
-		return nil, fmt.Errorf("failed to get L2 block by hash: %w", err)
-	}
-	if head == nil {
-		return nil, ethereum.NotFound
-	}
-
-	proof, err := s.GetProof(ctx, predeploys.L2ToL1MessagePasserAddr, []common.Hash{}, blockHash.String())
-	if err != nil {
-		return nil, fmt.Errorf("failed to get contract proof at block %s: %w", blockHash, err)
-	}
-	if proof == nil {
-		return nil, fmt.Errorf("proof %w", ethereum.NotFound)
-	}
-	// make sure that the proof (including storage hash) that we retrieved is correct by verifying it against the state-root
-	if err := proof.Verify(head.Root()); err != nil {
-		return nil, fmt.Errorf("invalid withdrawal root hash, state root was %s: %w", head.Root(), err)
-	}
-	stateRoot := head.Root()
-	return &eth.OutputV0{
-		StateRoot:                eth.Bytes32(stateRoot),
-		MessagePasserStorageRoot: eth.Bytes32(proof.StorageHash),
-		BlockHash:                blockHash,
-	}, nil
-}

op-node/testutils/mock_l2.go

@@ -43,11 +43,3 @@ func (m *MockL2Client) SystemConfigByL2Hash(ctx context.Context, hash common.Has
 func (m *MockL2Client) ExpectSystemConfigByL2Hash(hash common.Hash, cfg eth.SystemConfig, err error) {
 	m.Mock.On("SystemConfigByL2Hash", hash).Once().Return(cfg, &err)
 }
-
-func (m *MockL2Client) OutputV0AtBlock(ctx context.Context, blockHash common.Hash) (*eth.OutputV0, error) {
-	return m.Mock.MethodCalled("OutputV0AtBlock", blockHash).Get(0).(*eth.OutputV0), nil
-}
-
-func (m *MockL2Client) ExpectOutputV0AtBlock(blockHash common.Hash, output *eth.OutputV0, err error) {
-	m.Mock.On("OutputV0AtBlock", blockHash).Once().Return(output, &err)
-}

op-node/testutils/random.go

@@ -266,14 +266,7 @@ func RandomOutputResponse(rng *rand.Rand) *eth.OutputResponse {
 			UnsafeL2:           RandomL2BlockRef(rng),
 			SafeL2:             RandomL2BlockRef(rng),
 			FinalizedL2:        RandomL2BlockRef(rng),
+			EngineSyncTarget:   RandomL2BlockRef(rng),
 		},
 	}
 }
-
-func RandomOutputV0(rng *rand.Rand) *eth.OutputV0 {
-	return &eth.OutputV0{
-		StateRoot:                eth.Bytes32(RandomHash(rng)),
-		MessagePasserStorageRoot: eth.Bytes32(RandomHash(rng)),
-		BlockHash:                RandomHash(rng),
-	}
-}

op-program/client/boot.go

@@ -12,7 +12,7 @@ import (
 
 const (
 	L1HeadLocalIndex preimage.LocalIndexKey = iota + 1
-	L2OutputRootLocalIndex
+	L2HeadLocalIndex
 	L2ClaimLocalIndex
 	L2ClaimBlockNumberLocalIndex
 	L2ChainConfigLocalIndex
@@ -21,7 +21,7 @@ const (
 
 type BootInfo struct {
 	L1Head             common.Hash
-	L2OutputRoot       common.Hash
+	L2Head             common.Hash
 	L2Claim            common.Hash
 	L2ClaimBlockNumber uint64
 	L2ChainConfig      *params.ChainConfig
@@ -42,7 +42,7 @@ func NewBootstrapClient(r oracleClient) *BootstrapClient {
 
 func (br *BootstrapClient) BootInfo() *BootInfo {
 	l1Head := common.BytesToHash(br.r.Get(L1HeadLocalIndex))
-	l2OutputRoot := common.BytesToHash(br.r.Get(L2OutputRootLocalIndex))
+	l2Head := common.BytesToHash(br.r.Get(L2HeadLocalIndex))
 	l2Claim := common.BytesToHash(br.r.Get(L2ClaimLocalIndex))
 	l2ClaimBlockNumber := binary.BigEndian.Uint64(br.r.Get(L2ClaimBlockNumberLocalIndex))
 	l2ChainConfig := new(params.ChainConfig)
@@ -58,7 +58,7 @@ func (br *BootstrapClient) BootInfo() *BootInfo {
 
 	return &BootInfo{
 		L1Head:             l1Head,
-		L2OutputRoot:       l2OutputRoot,
+		L2Head:             l2Head,
 		L2Claim:            l2Claim,
 		L2ClaimBlockNumber: l2ClaimBlockNumber,
 		L2ChainConfig:      l2ChainConfig,

op-program/client/boot_test.go

@@ -15,7 +15,7 @@ import (
 func TestBootstrapClient(t *testing.T) {
 	bootInfo := &BootInfo{
 		L1Head:             common.HexToHash("0x1111"),
-		L2OutputRoot:       common.HexToHash("0x2222"),
+		L2Head:             common.HexToHash("0x2222"),
 		L2Claim:            common.HexToHash("0x3333"),
 		L2ClaimBlockNumber: 1,
 		L2ChainConfig:      params.GoerliChainConfig,
@@ -34,8 +34,8 @@ func (o *mockBoostrapOracle) Get(key preimage.Key) []byte {
 	switch key.PreimageKey() {
 	case L1HeadLocalIndex.PreimageKey():
 		return o.b.L1Head[:]
-	case L2OutputRootLocalIndex.PreimageKey():
-		return o.b.L2OutputRoot[:]
+	case L2HeadLocalIndex.PreimageKey():
+		return o.b.L2Head[:]
 	case L2ClaimLocalIndex.PreimageKey():
 		return o.b.L2Claim[:]
 	case L2ClaimBlockNumberLocalIndex.PreimageKey():

op-program/client/driver/driver.go

@@ -10,6 +10,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-node/metrics"
 	"github.com/ethereum-optimism/optimism/op-node/rollup"
 	"github.com/ethereum-optimism/optimism/op-node/rollup/derive"
+	"github.com/ethereum-optimism/optimism/op-node/rollup/sync"
 	"github.com/ethereum/go-ethereum/log"
 )
 
@@ -35,7 +36,7 @@ type Driver struct {
 }
 
 func NewDriver(logger log.Logger, cfg *rollup.Config, l1Source derive.L1Fetcher, l2Source L2Source, targetBlockNum uint64) *Driver {
-	pipeline := derive.NewDerivationPipeline(logger, cfg, l1Source, l2Source, metrics.NoopMetrics)
+	pipeline := derive.NewDerivationPipeline(logger, cfg, l1Source, l2Source, metrics.NoopMetrics, &sync.Config{})
 	pipeline.Reset()
 	return &Driver{
 		logger:         logger,

op-program/client/l2/cache.go

 package l2
 
 import (
-	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/hashicorp/golang-lru/v2/simplelru"
@@ -18,20 +17,17 @@ type CachingOracle struct {
 	blocks *simplelru.LRU[common.Hash, *types.Block]
 	nodes  *simplelru.LRU[common.Hash, []byte]
 	codes  *simplelru.LRU[common.Hash, []byte]
-	outputs *simplelru.LRU[common.Hash, eth.Output]
 }
 
 func NewCachingOracle(oracle Oracle) *CachingOracle {
 	blockLRU, _ := simplelru.NewLRU[common.Hash, *types.Block](blockCacheSize, nil)
 	nodeLRU, _ := simplelru.NewLRU[common.Hash, []byte](nodeCacheSize, nil)
 	codeLRU, _ := simplelru.NewLRU[common.Hash, []byte](codeCacheSize, nil)
-	outputLRU, _ := simplelru.NewLRU[common.Hash, eth.Output](codeCacheSize, nil)
 	return &CachingOracle{
 		oracle: oracle,
 		blocks: blockLRU,
 		nodes:  nodeLRU,
 		codes:  codeLRU,
-		outputs: outputLRU,
 	}
 }
 
@@ -64,13 +60,3 @@ func (o *CachingOracle) BlockByHash(blockHash common.Hash) *types.Block {
 	o.blocks.Add(blockHash, block)
 	return block
 }
-
-func (o *CachingOracle) OutputByRoot(root common.Hash) eth.Output {
-	output, ok := o.outputs.Get(root)
-	if ok {
-		return output
-	}
-	output = o.oracle.OutputByRoot(root)
-	o.outputs.Add(root, output)
-	return output
-}

op-program/client/l2/cache_test.go

@@ -4,7 +4,6 @@ import (
 	"math/rand"
 	"testing"
 
-	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum-optimism/optimism/op-node/testutils"
 	"github.com/ethereum-optimism/optimism/op-program/client/l2/test"
 	"github.com/ethereum/go-ethereum/common"
@@ -67,22 +66,3 @@ func TestCodeByHash(t *testing.T) {
 	actual = oracle.CodeByHash(hash)
 	require.Equal(t, node, actual)
 }
-
-func TestOutputByRoot(t *testing.T) {
-	stub, _ := test.NewStubOracle(t)
-	oracle := NewCachingOracle(stub)
-
-	rng := rand.New(rand.NewSource(1))
-	output := testutils.RandomOutputV0(rng)
-
-	// Initial call retrieves from the stub
-	root := common.Hash(eth.OutputRoot(output))
-	stub.Outputs[root] = output
-	actual := oracle.OutputByRoot(root)
-	require.Equal(t, output, actual)
-
-	// Later calls should retrieve from cache
-	delete(stub.Outputs, root)
-	actual = oracle.OutputByRoot(root)
-	require.Equal(t, output, actual)
-}

op-program/client/l2/engine_backend.go

@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"math/big"
 
-	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum-optimism/optimism/op-program/client/l2/engineapi"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/consensus"
@@ -40,13 +39,8 @@ type OracleBackedL2Chain struct {
 
 var _ engineapi.EngineBackend = (*OracleBackedL2Chain)(nil)
 
-func NewOracleBackedL2Chain(logger log.Logger, oracle Oracle, chainCfg *params.ChainConfig, l2OutputRoot common.Hash) (*OracleBackedL2Chain, error) {
-	output := oracle.OutputByRoot(l2OutputRoot)
-	outputV0, ok := output.(*eth.OutputV0)
-	if !ok {
-		return nil, fmt.Errorf("unsupported L2 output version: %d", output.Version())
-	}
-	head := oracle.BlockByHash(outputV0.BlockHash)
+func NewOracleBackedL2Chain(logger log.Logger, oracle Oracle, chainCfg *params.ChainConfig, l2Head common.Hash) (*OracleBackedL2Chain, error) {
+	head := oracle.BlockByHash(l2Head)
 	logger.Info("Loaded L2 head", "hash", head.Hash(), "number", head.Number())
 	return &OracleBackedL2Chain{
 		log:      logger,

op-program/client/l2/engine_backend_test.go

@@ -5,7 +5,6 @@ import (
 	"testing"
 
 	"github.com/ethereum-optimism/optimism/op-chain-ops/genesis"
-	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum-optimism/optimism/op-node/testlog"
 	"github.com/ethereum-optimism/optimism/op-program/client/l2/engineapi"
 	"github.com/ethereum-optimism/optimism/op-program/client/l2/engineapi/test"
@@ -200,8 +199,7 @@ func setupOracleBackedChainWithLowerHead(t *testing.T, blockCount int, headBlock
 	logger := testlog.Logger(t, log.LvlDebug)
 	chainCfg, blocks, oracle := setupOracle(t, blockCount, headBlockNumber)
 	head := blocks[headBlockNumber].Hash()
-	stubOutput := eth.OutputV0{BlockHash: head}
-	chain, err := NewOracleBackedL2Chain(logger, oracle, chainCfg, common.Hash(eth.OutputRoot(&stubOutput)))
+	chain, err := NewOracleBackedL2Chain(logger, oracle, chainCfg, head)
 	require.NoError(t, err)
 	return blocks, chain
 }
@@ -234,12 +232,7 @@ func setupOracle(t *testing.T, blockCount int, headBlockNumber int) (*params.Cha
 	genesisBlock := l2Genesis.MustCommit(db)
 	blocks, _ := core.GenerateChain(chainCfg, genesisBlock, consensus, db, blockCount, func(i int, gen *core.BlockGen) {})
 	blocks = append([]*types.Block{genesisBlock}, blocks...)
-
-	var outputs []eth.Output
-	for _, block := range blocks {
-		outputs = append(outputs, &eth.OutputV0{BlockHash: block.Hash()})
-	}
-	oracle := l2test.NewStubOracleWithBlocks(t, blocks[:headBlockNumber+1], outputs, db)
+	oracle := l2test.NewStubOracleWithBlocks(t, blocks[:headBlockNumber+1], db)
 	return chainCfg, blocks, oracle
 }
 

op-program/client/l2/hints.go

@@ -11,7 +11,6 @@ const (
 	HintL2Transactions = "l2-transactions"
 	HintL2Code         = "l2-code"
 	HintL2StateNode    = "l2-state-node"
-	HintL2Output       = "l2-output"
 )
 
 type BlockHeaderHint common.Hash
@@ -45,11 +44,3 @@ var _ preimage.Hint = StateNodeHint{}
 func (l StateNodeHint) Hint() string {
 	return HintL2StateNode + " " + (common.Hash)(l).String()
 }
-
-type L2OutputHint common.Hash
-
-var _ preimage.Hint = L2OutputHint{}
-
-func (l L2OutputHint) Hint() string {
-	return HintL2Output + " " + (common.Hash)(l).String()
-}

op-program/client/l2/oracle.go

@@ -32,8 +32,6 @@ type Oracle interface {
 
 	// BlockByHash retrieves the block with the given hash.
 	BlockByHash(blockHash common.Hash) *types.Block
-
-	OutputByRoot(root common.Hash) eth.Output
 }
 
 // PreimageOracle implements Oracle using by interfacing with the pure preimage.Oracle
@@ -87,13 +85,3 @@ func (p *PreimageOracle) CodeByHash(codeHash common.Hash) []byte {
 	p.hint.Hint(CodeHint(codeHash))
 	return p.oracle.Get(preimage.Keccak256Key(codeHash))
 }
-
-func (p *PreimageOracle) OutputByRoot(l2OutputRoot common.Hash) eth.Output {
-	p.hint.Hint(L2OutputHint(l2OutputRoot))
-	data := p.oracle.Get(preimage.Keccak256Key(l2OutputRoot))
-	output, err := eth.UnmarshalOutput(data)
-	if err != nil {
-		panic(fmt.Errorf("invalid L2 output data for root %s: %w", l2OutputRoot, err))
-	}
-	return output
-}

op-program/client/l2/oracle_test.go

@@ -122,21 +122,3 @@ func TestPreimageOracleCodeByHash(t *testing.T) {
 		})
 	}
 }
-
-func TestPreimageOracleOutputByRoot(t *testing.T) {
-	rng := rand.New(rand.NewSource(123))
-
-	for i := 0; i < 10; i++ {
-		t.Run(fmt.Sprintf("output_%d", i), func(t *testing.T) {
-			po, hints, preimages := mockPreimageOracle(t)
-			output := testutils.RandomOutputV0(rng)
-
-			h := common.Hash(eth.OutputRoot(output))
-			preimages[preimage.Keccak256Key(h).PreimageKey()] = output.Marshal()
-			hints.On("hint", L2OutputHint(h).Hint()).Once().Return()
-			gotOutput := po.OutputByRoot(h)
-			hints.AssertExpectations(t)
-			require.Equal(t, hexutil.Bytes(output.Marshal()), hexutil.Bytes(gotOutput.Marshal()), "output matches")
-		})
-	}
-}

op-program/client/l2/test/stub_oracle.go

@@ -3,7 +3,6 @@ package test
 import (
 	"testing"
 
-	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/rawdb"
 	"github.com/ethereum/go-ethereum/core/types"
@@ -19,7 +18,6 @@ type stateOracle interface {
 type StubBlockOracle struct {
 	t      *testing.T
 	Blocks map[common.Hash]*types.Block
-	Outputs map[common.Hash]eth.Output
 	stateOracle
 }
 
@@ -28,25 +26,18 @@ func NewStubOracle(t *testing.T) (*StubBlockOracle, *StubStateOracle) {
 	blockOracle := StubBlockOracle{
 		t:           t,
 		Blocks:      make(map[common.Hash]*types.Block),
-		Outputs:     make(map[common.Hash]eth.Output),
 		stateOracle: stateOracle,
 	}
 	return &blockOracle, stateOracle
 }
 
-func NewStubOracleWithBlocks(t *testing.T, chain []*types.Block, outputs []eth.Output, db ethdb.Database) *StubBlockOracle {
+func NewStubOracleWithBlocks(t *testing.T, chain []*types.Block, db ethdb.Database) *StubBlockOracle {
 	blocks := make(map[common.Hash]*types.Block, len(chain))
 	for _, block := range chain {
 		blocks[block.Hash()] = block
 	}
-	o := make(map[common.Hash]eth.Output, len(outputs))
-	for _, output := range outputs {
-		o[common.Hash(eth.OutputRoot(output))] = output
-	}
 	return &StubBlockOracle{
-		t:           t,
 		Blocks:      blocks,
-		Outputs:     o,
 		stateOracle: &KvStateOracle{t: t, Source: db},
 	}
 }
@@ -59,14 +50,6 @@ func (o StubBlockOracle) BlockByHash(blockHash common.Hash) *types.Block {
 	return block
 }
 
-func (o StubBlockOracle) OutputByRoot(root common.Hash) eth.Output {
-	output, ok := o.Outputs[root]
-	if !ok {
-		o.t.Fatalf("requested unknown output root %s", root)
-	}
-	return output
-}
-
 // KvStateOracle loads data from a source ethdb.KeyValueStore
 type KvStateOracle struct {
 	t      *testing.T

op-program/client/program.go

@@ -53,7 +53,7 @@ func RunProgram(logger log.Logger, preimageOracle io.ReadWriter, preimageHinter
 		bootInfo.RollupConfig,
 		bootInfo.L2ChainConfig,
 		bootInfo.L1Head,
-		bootInfo.L2OutputRoot,
+		bootInfo.L2Head,
 		bootInfo.L2Claim,
 		bootInfo.L2ClaimBlockNumber,
 		l1PreimageOracle,
@@ -62,9 +62,9 @@ func RunProgram(logger log.Logger, preimageOracle io.ReadWriter, preimageHinter
 }
 
 // runDerivation executes the L2 state transition, given a minimal interface to retrieve data.
-func runDerivation(logger log.Logger, cfg *rollup.Config, l2Cfg *params.ChainConfig, l1Head common.Hash, l2OutputRoot common.Hash, l2Claim common.Hash, l2ClaimBlockNum uint64, l1Oracle l1.Oracle, l2Oracle l2.Oracle) error {
+func runDerivation(logger log.Logger, cfg *rollup.Config, l2Cfg *params.ChainConfig, l1Head common.Hash, l2Head common.Hash, l2Claim common.Hash, l2ClaimBlockNum uint64, l1Oracle l1.Oracle, l2Oracle l2.Oracle) error {
 	l1Source := l1.NewOracleL1Client(logger, l1Oracle, l1Head)
-	engineBackend, err := l2.NewOracleBackedL2Chain(logger, l2Oracle, l2Cfg, l2OutputRoot)
+	engineBackend, err := l2.NewOracleBackedL2Chain(logger, l2Oracle, l2Cfg, l2Head)
 	if err != nil {
 		return fmt.Errorf("failed to create oracle-backed L2 chain: %w", err)
 	}

op-program/host/cmd/main_test.go

@@ -20,7 +20,6 @@ var (
 	l1HeadValue        = common.HexToHash("0x111111").Hex()
 	l2HeadValue        = common.HexToHash("0x222222").Hex()
 	l2ClaimValue       = common.HexToHash("0x333333").Hex()
-	l2OutputRoot       = common.HexToHash("0x444444").Hex()
 	l2ClaimBlockNumber = uint64(1203)
 	// Note: This is actually the L1 goerli genesis config. Just using it as an arbitrary, valid genesis config
 	l2Genesis       = core.DefaultGoerliGenesisBlock()
@@ -49,7 +48,6 @@ func TestDefaultCLIOptionsMatchDefaultConfig(t *testing.T) {
 		config.OPGoerliChainConfig,
 		common.HexToHash(l1HeadValue),
 		common.HexToHash(l2HeadValue),
-		common.HexToHash(l2OutputRoot),
 		common.HexToHash(l2ClaimValue),
 		l2ClaimBlockNumber)
 	require.Equal(t, defaultCfg, cfg)
@@ -133,21 +131,6 @@ func TestL2Head(t *testing.T) {
 	})
 }
 
-func TestL2OutputRoot(t *testing.T) {
-	t.Run("Required", func(t *testing.T) {
-		verifyArgsInvalid(t, "flag l2.outputroot is required", addRequiredArgsExcept("--l2.outputroot"))
-	})
-
-	t.Run("Valid", func(t *testing.T) {
-		cfg := configForArgs(t, replaceRequiredArg("--l2.outputroot", l2OutputRoot))
-		require.Equal(t, common.HexToHash(l2OutputRoot), cfg.L2OutputRoot)
-	})
-
-	t.Run("Invalid", func(t *testing.T) {
-		verifyArgsInvalid(t, config.ErrInvalidL2OutputRoot.Error(), replaceRequiredArg("--l2.outputroot", "something"))
-	})
-}
-
 func TestL1Head(t *testing.T) {
 	t.Run("Required", func(t *testing.T) {
 		verifyArgsInvalid(t, "flag l1.head is required", addRequiredArgsExcept("--l1.head"))
@@ -319,7 +302,6 @@ func requiredArgs() map[string]string {
 		"--network":        "goerli",
 		"--l1.head":        l1HeadValue,
 		"--l2.head":        l2HeadValue,
-		"--l2.outputroot":  l2OutputRoot,
 		"--l2.claim":       l2ClaimValue,
 		"--l2.blocknumber": strconv.FormatUint(l2ClaimBlockNumber, 10),
 	}

op-program/host/config/config.go

@@ -22,7 +22,6 @@ var (
 	ErrMissingL2Genesis    = errors.New("missing l2 genesis")
 	ErrInvalidL1Head       = errors.New("invalid l1 head")
 	ErrInvalidL2Head       = errors.New("invalid l2 head")
-	ErrInvalidL2OutputRoot = errors.New("invalid l2 output root")
 	ErrL1AndL2Inconsistent = errors.New("l1 and l2 options must be specified together or both omitted")
 	ErrInvalidL2Claim      = errors.New("invalid l2 claim")
 	ErrInvalidL2ClaimBlock = errors.New("invalid l2 claim block number")
@@ -42,11 +41,8 @@ type Config struct {
 	L1TrustRPC bool
 	L1RPCKind  sources.RPCProviderKind
 
-	// L2Head is the l2 block hash contained in the L2 Output referenced by the L2OutputRoot
-	// TODO(inphi): This can be made optional with hardcoded rollup configs and output oracle addresses by searching the oracle for the l2 output root
+	// L2Head is the agreed L2 block to start derivation from
 	L2Head common.Hash
-	// L2OutputRoot is the agreed L2 output root to start derivation from
-	L2OutputRoot common.Hash
 	L2URL  string
 	// L2Claim is the claimed L2 output root to verify
 	L2Claim common.Hash
@@ -77,9 +73,6 @@ func (c *Config) Check() error {
 	if c.L2Head == (common.Hash{}) {
 		return ErrInvalidL2Head
 	}
-	if c.L2OutputRoot == (common.Hash{}) {
-		return ErrInvalidL2OutputRoot
-	}
 	if c.L2Claim == (common.Hash{}) {
 		return ErrInvalidL2Claim
 	}
@@ -106,21 +99,12 @@ func (c *Config) FetchingEnabled() bool {
 }
 
 // NewConfig creates a Config with all optional values set to the CLI default value
-func NewConfig(
-	rollupCfg *rollup.Config,
-	l2Genesis *params.ChainConfig,
-	l1Head common.Hash,
-	l2Head common.Hash,
-	l2OutputRoot common.Hash,
-	l2Claim common.Hash,
-	l2ClaimBlockNum uint64,
-) *Config {
+func NewConfig(rollupCfg *rollup.Config, l2Genesis *params.ChainConfig, l1Head common.Hash, l2Head common.Hash, l2Claim common.Hash, l2ClaimBlockNum uint64) *Config {
 	return &Config{
 		Rollup:             rollupCfg,
 		L2ChainConfig:      l2Genesis,
 		L1Head:             l1Head,
 		L2Head:             l2Head,
-		L2OutputRoot:       l2OutputRoot,
 		L2Claim:            l2Claim,
 		L2ClaimBlockNumber: l2ClaimBlockNum,
 		L1RPCKind:          sources.RPCKindBasic,
@@ -139,10 +123,6 @@ func NewConfigFromCLI(log log.Logger, ctx *cli.Context) (*Config, error) {
 	if l2Head == (common.Hash{}) {
 		return nil, ErrInvalidL2Head
 	}
-	l2OutputRoot := common.HexToHash(ctx.String(flags.L2OutputRoot.Name))
-	if l2OutputRoot == (common.Hash{}) {
-		return nil, ErrInvalidL2OutputRoot
-	}
 	l2Claim := common.HexToHash(ctx.String(flags.L2Claim.Name))
 	if l2Claim == (common.Hash{}) {
 		return nil, ErrInvalidL2Claim
@@ -172,7 +152,6 @@ func NewConfigFromCLI(log log.Logger, ctx *cli.Context) (*Config, error) {
 		L2URL:              ctx.String(flags.L2NodeAddr.Name),
 		L2ChainConfig:      l2ChainConfig,
 		L2Head:             l2Head,
-		L2OutputRoot:       l2OutputRoot,
 		L2Claim:            l2Claim,
 		L2ClaimBlockNumber: l2ClaimBlockNum,
 		L1Head:             l1Head,

op-program/host/config/config_test.go

@@ -16,7 +16,6 @@ var (
 	validL1Head          = common.Hash{0xaa}
 	validL2Head          = common.Hash{0xbb}
 	validL2Claim         = common.Hash{0xcc}
-	validL2OutputRoot    = common.Hash{0xdd}
 	validL2ClaimBlockNum = uint64(15)
 )
 
@@ -56,13 +55,6 @@ func TestL2HeadRequired(t *testing.T) {
 	require.ErrorIs(t, err, ErrInvalidL2Head)
 }
 
-func TestL2OutputRootRequired(t *testing.T) {
-	config := validConfig()
-	config.L2OutputRoot = common.Hash{}
-	err := config.Check()
-	require.ErrorIs(t, err, ErrInvalidL2OutputRoot)
-}
-
 func TestL2ClaimRequired(t *testing.T) {
 	config := validConfig()
 	config.L2Claim = common.Hash{}
@@ -159,7 +151,7 @@ func TestRejectExecAndServerMode(t *testing.T) {
 }
 
 func validConfig() *Config {
-	cfg := NewConfig(validRollupConfig, validL2Genesis, validL1Head, validL2Head, validL2OutputRoot, validL2Claim, validL2ClaimBlockNum)
+	cfg := NewConfig(validRollupConfig, validL2Genesis, validL1Head, validL2Head, validL2Claim, validL2ClaimBlockNum)
 	cfg.DataDir = "/tmp/configTest"
 	return cfg
 }

op-program/host/flags/flags.go

@@ -47,14 +47,9 @@ var (
 	}
 	L2Head = &cli.StringFlag{
 		Name:    "l2.head",
-		Usage:   "Hash of the L2 block at l2.outputroot",
+		Usage:   "Hash of the agreed L2 block to start derivation from",
 		EnvVars: prefixEnvVars("L2_HEAD"),
 	}
-	L2OutputRoot = &cli.StringFlag{
-		Name:    "l2.outputroot",
-		Usage:   "Agreed L2 Output Root to start derivation from",
-		EnvVars: prefixEnvVars("L2_OUTPUT_ROOT"),
-	}
 	L2Claim = &cli.StringFlag{
 		Name:    "l2.claim",
 		Usage:   "Claimed L2 output root to validate",
@@ -108,7 +103,6 @@ var Flags []cli.Flag
 var requiredFlags = []cli.Flag{
 	L1Head,
 	L2Head,
-	L2OutputRoot,
 	L2Claim,
 	L2BlockNumber,
 }

op-program/host/host.go

@@ -26,7 +26,7 @@ import (
 )
 
 type L2Source struct {
-	*L2Client
+	*sources.L2Client
 	*sources.DebugClient
 }
 
@@ -205,7 +205,7 @@ func makePrefetcher(ctx context.Context, logger log.Logger, kv kvstore.KV, cfg *
 	if err != nil {
 		return nil, fmt.Errorf("failed to create L1 client: %w", err)
 	}
-	l2Cl, err := NewL2Client(l2RPC, logger, nil, &L2ClientConfig{L2ClientConfig: l2ClCfg, L2Head: cfg.L2Head})
+	l2Cl, err := sources.NewL2Client(l2RPC, logger, nil, l2ClCfg)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create L2 client: %w", err)
 	}

op-program/host/host_test.go

@@ -23,8 +23,7 @@ func TestServerMode(t *testing.T) {
 	dir := t.TempDir()
 
 	l1Head := common.Hash{0x11}
-	l2OutputRoot := common.Hash{0x33}
-	cfg := config.NewConfig(&chaincfg.Goerli, config.OPGoerliChainConfig, l1Head, common.Hash{0x22}, l2OutputRoot, common.Hash{0x44}, 1000)
+	cfg := config.NewConfig(&chaincfg.Goerli, config.OPGoerliChainConfig, l1Head, common.Hash{0x22}, common.Hash{0x33}, 1000)
 	cfg.DataDir = dir
 	cfg.ServerMode = true
 
@@ -44,8 +43,7 @@ func TestServerMode(t *testing.T) {
 	hClient := preimage.NewHintWriter(hintClient)
 	l1PreimageOracle := l1.NewPreimageOracle(pClient, hClient)
 
-	require.Equal(t, l1Head.Bytes(), pClient.Get(client.L1HeadLocalIndex), "Should get l1 head preimages")
-	require.Equal(t, l2OutputRoot.Bytes(), pClient.Get(client.L2OutputRootLocalIndex), "Should get l2 output root preimages")
+	require.Equal(t, l1Head.Bytes(), pClient.Get(client.L1HeadLocalIndex), "Should get preimages")
 
 	// Should exit when a preimage is unavailable
 	require.Panics(t, func() {

op-program/host/kvstore/local.go

@@ -19,7 +19,7 @@ func NewLocalPreimageSource(config *config.Config) *LocalPreimageSource {
 
 var (
 	l1HeadKey             = client.L1HeadLocalIndex.PreimageKey()
-	l2OutputRootKey       = client.L2OutputRootLocalIndex.PreimageKey()
+	l2HeadKey             = client.L2HeadLocalIndex.PreimageKey()
 	l2ClaimKey            = client.L2ClaimLocalIndex.PreimageKey()
 	l2ClaimBlockNumberKey = client.L2ClaimBlockNumberLocalIndex.PreimageKey()
 	l2ChainConfigKey      = client.L2ChainConfigLocalIndex.PreimageKey()
@@ -30,8 +30,8 @@ func (s *LocalPreimageSource) Get(key common.Hash) ([]byte, error) {
 	switch [32]byte(key) {
 	case l1HeadKey:
 		return s.config.L1Head.Bytes(), nil
-	case l2OutputRootKey:
-		return s.config.L2OutputRoot.Bytes(), nil
+	case l2HeadKey:
+		return s.config.L2Head.Bytes(), nil
 	case l2ClaimKey:
 		return s.config.L2Claim.Bytes(), nil
 	case l2ClaimBlockNumberKey:

op-program/host/kvstore/local_test.go

@@ -17,7 +17,7 @@ func TestLocalPreimageSource(t *testing.T) {
 	cfg := &config.Config{
 		Rollup:             &chaincfg.Goerli,
 		L1Head:             common.HexToHash("0x1111"),
-		L2OutputRoot:       common.HexToHash("0x2222"),
+		L2Head:             common.HexToHash("0x2222"),
 		L2Claim:            common.HexToHash("0x3333"),
 		L2ClaimBlockNumber: 1234,
 		L2ChainConfig:      params.GoerliChainConfig,
@@ -29,7 +29,7 @@ func TestLocalPreimageSource(t *testing.T) {
 		expected []byte
 	}{
 		{"L1Head", l1HeadKey, cfg.L1Head.Bytes()},
-		{"L2OutputRoot", l2OutputRootKey, cfg.L2OutputRoot.Bytes()},
+		{"L2Head", l2HeadKey, cfg.L2Head.Bytes()},
 		{"L2Claim", l2ClaimKey, cfg.L2Claim.Bytes()},
 		{"L2ClaimBlockNumber", l2ClaimBlockNumberKey, binary.BigEndian.AppendUint64(nil, cfg.L2ClaimBlockNumber)},
 		{"Rollup", rollupKey, asJson(t, cfg.Rollup)},

op-program/host/l2_client.go

-package host
-
-import (
-	"context"
-	"fmt"
-
-	"github.com/ethereum-optimism/optimism/op-node/client"
-	"github.com/ethereum-optimism/optimism/op-node/eth"
-	"github.com/ethereum-optimism/optimism/op-node/sources"
-	"github.com/ethereum-optimism/optimism/op-node/sources/caching"
-	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/log"
-)
-
-type L2Client struct {
-	*sources.L2Client
-
-	// l2Head is the L2 block hash that we use to fetch L2 output
-	l2Head common.Hash
-}
-
-type L2ClientConfig struct {
-	*sources.L2ClientConfig
-	L2Head common.Hash
-}
-
-func NewL2Client(client client.RPC, log log.Logger, metrics caching.Metrics, config *L2ClientConfig) (*L2Client, error) {
-	l2Client, err := sources.NewL2Client(client, log, metrics, config.L2ClientConfig)
-	if err != nil {
-		return nil, err
-	}
-	return &L2Client{
-		L2Client: l2Client,
-		l2Head:   config.L2Head,
-	}, nil
-}
-
-func (s *L2Client) OutputByRoot(ctx context.Context, l2OutputRoot common.Hash) (eth.Output, error) {
-	output, err := s.OutputV0AtBlock(ctx, s.l2Head)
-	if err != nil {
-		return nil, err
-	}
-	if eth.OutputRoot(output) != eth.Bytes32(l2OutputRoot) {
-		// For fault proofs, we only reference outputs at the l2 head at boot time
-		// The caller shouldn't be requesting outputs at any other block
-		return nil, fmt.Errorf("unknown output root")
-	}
-	return output, nil
-}

op-program/host/prefetcher/prefetcher.go

@@ -29,7 +29,6 @@ type L2Source interface {
 	InfoAndTxsByHash(ctx context.Context, blockHash common.Hash) (eth.BlockInfo, types.Transactions, error)
 	NodeByHash(ctx context.Context, hash common.Hash) ([]byte, error)
 	CodeByHash(ctx context.Context, hash common.Hash) ([]byte, error)
-	OutputByRoot(ctx context.Context, root common.Hash) (eth.Output, error)
 }
 
 type Prefetcher struct {
@@ -125,12 +124,6 @@ func (p *Prefetcher) prefetch(ctx context.Context, hint string) error {
 			return fmt.Errorf("failed to fetch L2 contract code %s: %w", hash, err)
 		}
 		return p.kvStore.Put(preimage.Keccak256Key(hash).PreimageKey(), code)
-	case l2.HintL2Output:
-		output, err := p.l2Fetcher.OutputByRoot(ctx, hash)
-		if err != nil {
-			return fmt.Errorf("failed to fetch L2 output root %s: %w", hash, err)
-		}
-		return p.kvStore.Put(preimage.Keccak256Key(hash).PreimageKey(), output.Marshal())
 	}
 	return fmt.Errorf("unknown hint type: %v", hintType)
 }

op-program/host/prefetcher/prefetcher_test.go

@@ -286,15 +286,6 @@ type l2Client struct {
 	*testutils.MockDebugClient
 }
 
-func (m *l2Client) OutputByRoot(ctx context.Context, root common.Hash) (eth.Output, error) {
-	out := m.Mock.MethodCalled("OutputByRoot", root)
-	return out[0].(eth.Output), *out[1].(*error)
-}
-
-func (m *l2Client) ExpectOutputByRoot(root common.Hash, output eth.Output, err error) {
-	m.Mock.On("OutputByRoot", root).Once().Return(output, &err)
-}
-
 func createPrefetcher(t *testing.T) (*Prefetcher, *testutils.MockL1Source, *l2Client, kvstore.KV) {
 	logger := testlog.Logger(t, log.LvlDebug)
 	kv := kvstore.NewMemKV()

op-program/host/prefetcher/retry.go

@@ -125,20 +125,6 @@ func (s *RetryingL2Source) CodeByHash(ctx context.Context, hash common.Hash) ([]
 	return code, err
 }
 
-func (s *RetryingL2Source) OutputByRoot(ctx context.Context, root common.Hash) (eth.Output, error) {
-	var output eth.Output
-	err := backoff.DoCtx(ctx, maxAttempts, s.strategy, func() error {
-		o, err := s.source.OutputByRoot(ctx, root)
-		if err != nil {
-			s.logger.Warn("Failed to fetch l2 output", "root", root, "err", err)
-			return err
-		}
-		output = o
-		return nil
-	})
-	return output, err
-}
-
 func NewRetryingL2Source(logger log.Logger, source L2Source) *RetryingL2Source {
 	return &RetryingL2Source{
 		logger:   logger,

op-program/host/prefetcher/retry_test.go

@@ -119,8 +119,6 @@ func TestRetryingL2Source(t *testing.T) {
 		&types.Transaction{},
 	}
 	data := []byte{1, 2, 3, 4, 5}
-	output := &eth.OutputV0{}
-	wrongOutput := &eth.OutputV0{BlockHash: common.Hash{0x99}}
 
 	t.Run("InfoAndTxsByHash Success", func(t *testing.T) {
 		source, mock := createL2Source(t)
@@ -189,28 +187,6 @@ func TestRetryingL2Source(t *testing.T) {
 		require.NoError(t, err)
 		require.Equal(t, data, actual)
 	})
-
-	t.Run("OutputByRoot Success", func(t *testing.T) {
-		source, mock := createL2Source(t)
-		defer mock.AssertExpectations(t)
-		mock.ExpectOutputByRoot(hash, output, nil)
-
-		actualOutput, err := source.OutputByRoot(ctx, hash)
-		require.NoError(t, err)
-		require.Equal(t, output, actualOutput)
-	})
-
-	t.Run("OutputByRoot Error", func(t *testing.T) {
-		source, mock := createL2Source(t)
-		defer mock.AssertExpectations(t)
-		expectedErr := errors.New("boom")
-		mock.ExpectOutputByRoot(hash, wrongOutput, expectedErr)
-		mock.ExpectOutputByRoot(hash, output, nil)
-
-		actualOutput, err := source.OutputByRoot(ctx, hash)
-		require.NoError(t, err)
-		require.Equal(t, output, actualOutput)
-	})
 }
 
 func createL2Source(t *testing.T) (*RetryingL2Source, *MockL2Source) {
@@ -241,11 +217,6 @@ func (m *MockL2Source) CodeByHash(ctx context.Context, hash common.Hash) ([]byte
 	return out[0].([]byte), *out[1].(*error)
 }
 
-func (m *MockL2Source) OutputByRoot(ctx context.Context, root common.Hash) (eth.Output, error) {
-	out := m.Mock.MethodCalled("OutputByRoot", root)
-	return out[0].(eth.Output), *out[1].(*error)
-}
-
 func (m *MockL2Source) ExpectInfoAndTxsByHash(blockHash common.Hash, info eth.BlockInfo, txs types.Transactions, err error) {
 	m.Mock.On("InfoAndTxsByHash", blockHash).Once().Return(info, txs, &err)
 }
@@ -258,8 +229,4 @@ func (m *MockL2Source) ExpectCodeByHash(hash common.Hash, code []byte, err error
 	m.Mock.On("CodeByHash", hash).Once().Return(code, &err)
 }
 
-func (m *MockL2Source) ExpectOutputByRoot(root common.Hash, output eth.Output, err error) {
-	m.Mock.On("OutputByRoot", root).Once().Return(output, &err)
-}
-
 var _ L2Source = (*MockL2Source)(nil)

op-program/verify/cmd/goerli.go

@@ -100,31 +100,7 @@ func Run(l1RpcUrl string, l2RpcUrl string, l2OracleAddr common.Address) error {
 	if err != nil {
 		return fmt.Errorf("retrieve agreed l2 block: %w", err)
 	}
-	agreedOutputIndex, err := outputOracle.GetL2OutputIndexAfter(callOpts, l2AgreedBlock.Number())
-	if err != nil {
-		return fmt.Errorf("failed to output index after agreed block")
-	}
-	// Find an output that differs from what is being claimed
-	var agreedOutput bindings.TypesOutputProposal
-	for {
-		agreedOutput, err = outputOracle.GetL2Output(callOpts, agreedOutputIndex)
-		if err != nil {
-			return fmt.Errorf("retrieve agreed output: %w", err)
-		}
-		if agreedOutput.OutputRoot != output.OutputRoot {
-			break
-		}
-		fmt.Printf("Output at %v equals output at finalized block. Continuing search...\n", agreedOutput.L2BlockNumber)
-		agreedOutputIndex.Sub(agreedOutputIndex, big.NewInt(1))
-		if agreedOutputIndex.Int64() < 0 {
-			return fmt.Errorf("failed to find an output different from finalized block output")
-		}
-	}
-	l2BlockAtOutput, err := l2Client.BlockByNumber(ctx, agreedOutput.L2BlockNumber)
-	if err != nil {
-		return fmt.Errorf("retrieve agreed block: %w", err)
-	}
-	l2Head := l2BlockAtOutput.Hash()
+	l2Head := l2AgreedBlock.Hash()
 
 	temp, err := os.MkdirTemp("", "oracledata")
 	if err != nil {
@@ -144,7 +120,6 @@ func Run(l1RpcUrl string, l2RpcUrl string, l2OracleAddr common.Address) error {
 		"--datadir", temp,
 		"--l1.head", l1Head.Hex(),
 		"--l2.head", l2Head.Hex(),
-		"--l2.outputroot", common.Bytes2Hex(agreedOutput.OutputRoot[:]),
 		"--l2.claim", l2Claim.Hex(),
 		"--l2.blocknumber", l2BlockNumber.String(),
 	}

op-ufm/pkg/metrics/metrics.go

@@ -94,7 +94,8 @@ func RecordError(provider string, errorLabel string) {
 func RecordErrorDetails(provider string, label string, err error) {
 	errClean := nonAlphanumericRegex.ReplaceAllString(err.Error(), "")
 	errClean = strings.ReplaceAll(errClean, " ", "_")
-	label = fmt.Sprintf("%s.%s", label)
+	errClean = strings.ReplaceAll(errClean, "__", "_")
+	label = fmt.Sprintf("%s.%s", label, errClean)
 	RecordError(provider, label)
 }
 

op-ufm/tools/kmstool/main.go

@@ -44,10 +44,11 @@ func resolveAddr(ctx context.Context, client *kms.KeyManagementClient, keyName s
 	if err != nil {
 		return common.Address{}, fmt.Errorf("google kms public key %q lookup: %w", keyName, err)
 	}
+	keyPem := resp.Pem
 
-	block, _ := pem.Decode([]byte(resp.Pem))
+	block, _ := pem.Decode([]byte(keyPem))
 	if block == nil {
-		return common.Address{}, fmt.Errorf("google kms public key %q pem empty: %.130q", keyName, resp.Pem)
+		return common.Address{}, fmt.Errorf("google kms public key %q pem empty: %.130q", keyName, keyPem)
 	}
 
 	var info struct {
@@ -59,11 +60,6 @@ func resolveAddr(ctx context.Context, client *kms.KeyManagementClient, keyName s
 		return common.Address{}, fmt.Errorf("google kms public key %q pem block %q: %v", keyName, block.Type, err)
 	}
 
-	wantAlg := asn1.ObjectIdentifier{1, 2, 840, 10045, 2, 1}
-	if gotAlg := info.AlgID.Algorithm; !gotAlg.Equal(wantAlg) {
-		return common.Address{}, fmt.Errorf("google kms public key %q asn.1 algorithm %s intead of %s", keyName, gotAlg, wantAlg)
-	}
-
 	return pubKeyAddr(info.Key.Bytes), nil
 }
 

packages/chain-mon/CHANGELOG.md

 # @eth-optimism/drippie-mon
 
+## 0.4.2
+
+### Patch Changes
+
+- [#6469](https://github.com/ethereum-optimism/optimism/pull/6469) [`0c769680e`](https://github.com/ethereum-optimism/optimism/commit/0c769680e44208c086deef2f9c03c37da2b536fe) Thanks [@maurelian](https://github.com/maurelian)! - Update language in fault-mon from batches to outputs
+
 ## 0.4.1
 
 ### Patch Changes

packages/chain-mon/package.json

 {
   "private": true,
   "name": "@eth-optimism/chain-mon",
-  "version": "0.4.1",
+  "version": "0.4.2",
   "description": "[Optimism] Chain monitoring services",
   "main": "dist/index",
   "types": "dist/index",

packages/chain-mon/src/fault-mon/helpers.ts

@@ -31,22 +31,22 @@ export const findOutputForIndex = async (
 }
 
 /**
- * Finds the first state batch index that has not yet passed the fault proof window.
+ * Finds the first L2 output index that has not yet passed the fault proof window.
  *
  * @param oracle Output oracle contract.
- * @returns Starting state root batch index.
+ * @returns Starting L2 output index.
  */
-export const findFirstUnfinalizedStateBatchIndex = async (
+export const findFirstUnfinalizedOutputIndex = async (
   oracle: Contract,
   fpw: number,
   logger?: Logger
 ): Promise<number> => {
   const latestBlock = await oracle.provider.getBlock('latest')
-  const totalBatches = (await oracle.nextOutputIndex()).toNumber()
+  const totalOutputs = (await oracle.nextOutputIndex()).toNumber()
 
   // Perform a binary search to find the next batch that will pass the challenge period.
   let lo = 0
-  let hi = totalBatches
+  let hi = totalOutputs
   while (lo !== hi) {
     const mid = Math.floor((lo + hi) / 2)
     const outputData = await findOutputForIndex(oracle, mid, logger)
@@ -60,7 +60,7 @@ export const findFirstUnfinalizedStateBatchIndex = async (
 
   // Result will be zero if the chain is less than FPW seconds old. Only returns undefined in the
   // case that no batches have been submitted for an entire challenge period.
-  if (lo === totalBatches) {
+  if (lo === totalOutputs) {
     return undefined
   } else {
     return lo

packages/chain-mon/src/fault-mon/service.ts

@@ -25,20 +25,17 @@ import { Contract, ethers } from 'ethers'
 import dateformat from 'dateformat'
 
 import { version } from '../../package.json'
-import {
-  findFirstUnfinalizedStateBatchIndex,
-  findOutputForIndex,
-} from './helpers'
+import { findFirstUnfinalizedOutputIndex, findOutputForIndex } from './helpers'
 
 type Options = {
   l1RpcProvider: Provider
   l2RpcProvider: Provider
-  startBatchIndex: number
+  startOutputIndex: number
   optimismPortalAddress?: string
 }
 
 type Metrics = {
-  highestBatchIndex: Gauge
+  highestOutputIndex: Gauge
   isCurrentlyMismatched: Gauge
   nodeConnectionFailures: Gauge
 }
@@ -47,7 +44,7 @@ type State = {
   faultProofWindow: number
   outputOracle: Contract
   messenger: CrossChainMessenger
-  currentBatchIndex: number
+  currentOutputIndex: number
   diverged: boolean
 }
 
@@ -70,7 +67,7 @@ export class FaultDetector extends BaseServiceV2<Options, Metrics, State> {
           validator: validators.provider,
           desc: 'Provider for interacting with L2',
         },
-        startBatchIndex: {
+        startOutputIndex: {
           validator: validators.num,
           default: -1,
           desc: 'The L2 height to start from',
@@ -84,9 +81,9 @@ export class FaultDetector extends BaseServiceV2<Options, Metrics, State> {
         },
       },
       metricsSpec: {
-        highestBatchIndex: {
+        highestOutputIndex: {
           type: Gauge,
-          desc: 'Highest batch indices (checked and known)',
+          desc: 'Highest output indices (checked and known)',
           labels: ['type'],
         },
         isCurrentlyMismatched: {
@@ -200,30 +197,32 @@ export class FaultDetector extends BaseServiceV2<Options, Metrics, State> {
     this.state.outputOracle = this.state.messenger.contracts.l1.L2OutputOracle
 
     // Figure out where to start syncing from.
-    if (this.options.startBatchIndex === -1) {
-      this.logger.info('finding appropriate starting unfinalized batch')
-      const firstUnfinalized = await findFirstUnfinalizedStateBatchIndex(
+    if (this.options.startOutputIndex === -1) {
+      this.logger.info('finding appropriate starting unfinalized output')
+      const firstUnfinalized = await findFirstUnfinalizedOutputIndex(
         this.state.outputOracle,
         this.state.faultProofWindow,
         this.logger
       )
 
-      // We may not have an unfinalized batches in the case where no batches have been submitted
+      // We may not have an unfinalized outputs in the case where no outputs have been submitted
       // for the entire duration of the FAULTPROOFWINDOW. We generally do not expect this to happen on mainnet,
       // but it happens often on testnets because the FAULTPROOFWINDOW is very short.
       if (firstUnfinalized === undefined) {
-        this.logger.info('no unfinalized batches found. skipping all batches.')
-        const totalBatches = await this.state.outputOracle.nextOutputIndex()
-        this.state.currentBatchIndex = totalBatches.toNumber() - 1
+        this.logger.info(
+          'no unfinalized outputes found. skipping all outputes.'
+        )
+        const totalOutputes = await this.state.outputOracle.nextOutputIndex()
+        this.state.currentOutputIndex = totalOutputes.toNumber() - 1
       } else {
-        this.state.currentBatchIndex = firstUnfinalized
+        this.state.currentOutputIndex = firstUnfinalized
       }
     } else {
-      this.state.currentBatchIndex = this.options.startBatchIndex
+      this.state.currentOutputIndex = this.options.startOutputIndex
     }
 
-    this.logger.info('starting batch', {
-      batchIndex: this.state.currentBatchIndex,
+    this.logger.info('starting output', {
+      outputIndex: this.state.currentOutputIndex,
     })
 
     // Set the initial metrics.
@@ -241,12 +240,12 @@ export class FaultDetector extends BaseServiceV2<Options, Metrics, State> {
   async main(): Promise<void> {
     const startMs = Date.now()
 
-    let latestBatchIndex: number
+    let latestOutputIndex: number
     try {
-      const totalBatches = await this.state.outputOracle.nextOutputIndex()
-      latestBatchIndex = totalBatches.toNumber() - 1
+      const totalOutputes = await this.state.outputOracle.nextOutputIndex()
+      latestOutputIndex = totalOutputes.toNumber() - 1
     } catch (err) {
-      this.logger.error('failed to query total # of batches', {
+      this.logger.error('failed to query total # of outputes', {
         error: err,
         node: 'l1',
         section: 'nextOutputIndex',
@@ -259,34 +258,34 @@ export class FaultDetector extends BaseServiceV2<Options, Metrics, State> {
       return
     }
 
-    if (this.state.currentBatchIndex > latestBatchIndex) {
-      this.logger.info('batch index is ahead of the oracle. waiting...', {
-        batchIndex: this.state.currentBatchIndex,
-        latestBatchIndex,
+    if (this.state.currentOutputIndex > latestOutputIndex) {
+      this.logger.info('output index is ahead of the oracle. waiting...', {
+        outputIndex: this.state.currentOutputIndex,
+        latestOutputIndex,
       })
       await sleep(15000)
       return
     }
 
-    this.metrics.highestBatchIndex.set({ type: 'known' }, latestBatchIndex)
-    this.logger.info('checking batch', {
-      batchIndex: this.state.currentBatchIndex,
-      latestBatchIndex,
+    this.metrics.highestOutputIndex.set({ type: 'known' }, latestOutputIndex)
+    this.logger.info('checking output', {
+      outputIndex: this.state.currentOutputIndex,
+      latestOutputIndex,
     })
 
     let outputData: BedrockOutputData
     try {
       outputData = await findOutputForIndex(
         this.state.outputOracle,
-        this.state.currentBatchIndex,
+        this.state.currentOutputIndex,
         this.logger
       )
     } catch (err) {
-      this.logger.error('failed to fetch output associated with batch', {
+      this.logger.error('failed to fetch output associated with output', {
         error: err,
         node: 'l1',
         section: 'findOutputForIndex',
-        batchIndex: this.state.currentBatchIndex,
+        outputIndex: this.state.currentOutputIndex,
       })
       this.metrics.nodeConnectionFailures.inc({
         layer: 'l1',
@@ -397,20 +396,20 @@ export class FaultDetector extends BaseServiceV2<Options, Metrics, State> {
 
     const elapsedMs = Date.now() - startMs
 
-    // Mark the current batch index as checked
-    this.logger.info('checked batch ok', {
-      batchIndex: this.state.currentBatchIndex,
+    // Mark the current output index as checked
+    this.logger.info('checked output ok', {
+      outputIndex: this.state.currentOutputIndex,
       timeMs: elapsedMs,
     })
-    this.metrics.highestBatchIndex.set(
+    this.metrics.highestOutputIndex.set(
       { type: 'checked' },
-      this.state.currentBatchIndex
+      this.state.currentOutputIndex
     )
 
     // If we got through the above without throwing an error, we should be
-    // fine to reset and move onto the next batch
+    // fine to reset and move onto the next output
     this.state.diverged = false
-    this.state.currentBatchIndex++
+    this.state.currentOutputIndex++
     this.metrics.isCurrentlyMismatched.set(0)
   }
 }

packages/chain-mon/src/wd-mon/helpers.ts

+import { Provider } from '@ethersproject/abstract-provider'
+import { Logger } from '@eth-optimism/common-ts'
+
+/**
+ * Finds
+ *
+ * @param
+ * @param
+ * @param
+ * @returns
+ */
+export const getLastFinalizedBlock = async (
+  l1RpcProvider: Provider,
+  faultProofWindow: number,
+  logger: Logger
+): Promise<number> => {
+  let guessWindowStartBlock
+  try {
+    const l1Block = await l1RpcProvider.getBlock('latest')
+
+    // The time corresponding to the start of the FPW, based on the current block.
+    const windowStartTime = l1Block.timestamp - faultProofWindow
+
+    // Use the FPW to find the block number that is the start of the FPW.
+    guessWindowStartBlock = l1Block.number - faultProofWindow / 12
+
+    let block = await l1RpcProvider.getBlock(guessWindowStartBlock)
+    while (block.timestamp > windowStartTime) {
+      guessWindowStartBlock--
+      block = await l1RpcProvider.getBlock(guessWindowStartBlock)
+    }
+    return block.number
+  } catch (err) {
+    logger.fatal('error when calling querying for block', {
+      errors: err,
+    })
+    throw new Error(
+      `unable to find block number ${guessWindowStartBlock || 'latest'}`
+    )
+  }
+}

packages/chain-mon/src/wd-mon/service.ts

@@ -13,6 +13,7 @@ import { Event } from 'ethers'
 import dateformat from 'dateformat'
 
 import { version } from '../../package.json'
+import { getLastFinalizedBlock as getLastFinalizedBlock } from './helpers'
 
 type Options = {
   l1RpcProvider: Provider
@@ -30,7 +31,7 @@ type Metrics = {
 type State = {
   messenger: CrossChainMessenger
   highestUncheckedBlockNumber: number
-  finalizationWindow: number
+  faultProofWindow: number
   forgeryDetected: boolean
 }
 
@@ -109,10 +110,20 @@ export class WithdrawalMonitor extends BaseServiceV2<Options, Metrics, State> {
     // Not detected by default.
     this.state.forgeryDetected = false
 
-    // For now we'll just start take it from the env or the tip of the chain
+    this.state.faultProofWindow =
+      await this.state.messenger.getChallengePeriodSeconds()
+    this.logger.info(
+      `fault proof window is ${this.state.faultProofWindow} seconds`
+    )
+
+    // Set the start block number.
     if (this.options.startBlockNumber === -1) {
-      this.state.highestUncheckedBlockNumber =
-        await this.options.l1RpcProvider.getBlockNumber()
+      // We default to starting from the last finalized block.
+      this.state.highestUncheckedBlockNumber = await getLastFinalizedBlock(
+        this.options.l1RpcProvider,
+        this.state.faultProofWindow,
+        this.logger
+      )
     } else {
       this.state.highestUncheckedBlockNumber = this.options.startBlockNumber
     }

packages/chain-mon/test/fault-mon/helpers.spec.ts

@@ -8,7 +8,7 @@ import { SignerWithAddress } from '@nomiclabs/hardhat-ethers/signers'
 import { expect } from './setup'
 import {
   findOutputForIndex,
-  findFirstUnfinalizedStateBatchIndex,
+  findFirstUnfinalizedOutputIndex,
 } from '../../src/fault-mon'
 
 describe('helpers', () => {
@@ -122,7 +122,7 @@ describe('helpers', () => {
       })
 
       it('should find the first batch older than the FPW', async () => {
-        const first = await findFirstUnfinalizedStateBatchIndex(
+        const first = await findFirstUnfinalizedOutputIndex(
           L2OutputOracle,
           deployConfig.finalizationPeriodSeconds
         )
@@ -164,7 +164,7 @@ describe('helpers', () => {
       })
 
       it('should return zero', async () => {
-        const first = await findFirstUnfinalizedStateBatchIndex(
+        const first = await findFirstUnfinalizedOutputIndex(
           L2OutputOracle,
           deployConfig.finalizationPeriodSeconds
         )
@@ -214,7 +214,7 @@ describe('helpers', () => {
       })
 
       it('should return undefined', async () => {
-        const first = await findFirstUnfinalizedStateBatchIndex(
+        const first = await findFirstUnfinalizedOutputIndex(
           L2OutputOracle,
           deployConfig.finalizationPeriodSeconds
         )

packages/contracts-bedrock/.gas-snapshot

@@ -85,35 +85,35 @@ FaucetTest:test_nonAdmin_drip_fails() (gas: 262520)
 FaucetTest:test_receive_succeeds() (gas: 17401)
 FaucetTest:test_withdraw_nonAdmin_reverts() (gas: 13145)
 FaucetTest:test_withdraw_succeeds() (gas: 78359)
-FaultDisputeGame_ResolvesCorrectly_CorrectRoot1:test_resolvesCorrectly_succeeds() (gas: 498839)
-FaultDisputeGame_ResolvesCorrectly_CorrectRoot2:test_resolvesCorrectly_succeeds() (gas: 505685)
-FaultDisputeGame_ResolvesCorrectly_CorrectRoot3:test_resolvesCorrectly_succeeds() (gas: 502382)
-FaultDisputeGame_ResolvesCorrectly_CorrectRoot4:test_resolvesCorrectly_succeeds() (gas: 505561)
-FaultDisputeGame_ResolvesCorrectly_CorrectRoot5:test_resolvesCorrectly_succeeds() (gas: 504878)
-FaultDisputeGame_ResolvesCorrectly_IncorrectRoot1:test_resolvesCorrectly_succeeds() (gas: 497604)
-FaultDisputeGame_ResolvesCorrectly_IncorrectRoot2:test_resolvesCorrectly_succeeds() (gas: 504450)
-FaultDisputeGame_ResolvesCorrectly_IncorrectRoot3:test_resolvesCorrectly_succeeds() (gas: 501147)
-FaultDisputeGame_ResolvesCorrectly_IncorrectRoot4:test_resolvesCorrectly_succeeds() (gas: 502326)
-FaultDisputeGame_ResolvesCorrectly_IncorrectRoot5:test_resolvesCorrectly_succeeds() (gas: 501643)
+FaultDisputeGame_ResolvesCorrectly_CorrectRoot1:test_resolvesCorrectly_succeeds() (gas: 501957)
+FaultDisputeGame_ResolvesCorrectly_CorrectRoot2:test_resolvesCorrectly_succeeds() (gas: 508759)
+FaultDisputeGame_ResolvesCorrectly_CorrectRoot3:test_resolvesCorrectly_succeeds() (gas: 505478)
+FaultDisputeGame_ResolvesCorrectly_CorrectRoot4:test_resolvesCorrectly_succeeds() (gas: 508657)
+FaultDisputeGame_ResolvesCorrectly_CorrectRoot5:test_resolvesCorrectly_succeeds() (gas: 507974)
+FaultDisputeGame_ResolvesCorrectly_IncorrectRoot1:test_resolvesCorrectly_succeeds() (gas: 500722)
+FaultDisputeGame_ResolvesCorrectly_IncorrectRoot2:test_resolvesCorrectly_succeeds() (gas: 507524)
+FaultDisputeGame_ResolvesCorrectly_IncorrectRoot3:test_resolvesCorrectly_succeeds() (gas: 504243)
+FaultDisputeGame_ResolvesCorrectly_IncorrectRoot4:test_resolvesCorrectly_succeeds() (gas: 505422)
+FaultDisputeGame_ResolvesCorrectly_IncorrectRoot5:test_resolvesCorrectly_succeeds() (gas: 504739)
 FaultDisputeGame_Test:test_extraData_succeeds() (gas: 17404)
-FaultDisputeGame_Test:test_gameData_succeeds() (gas: 17917)
+FaultDisputeGame_Test:test_gameData_succeeds() (gas: 17939)
 FaultDisputeGame_Test:test_gameStart_succeeds() (gas: 10315)
 FaultDisputeGame_Test:test_gameType_succeeds() (gas: 8260)
-FaultDisputeGame_Test:test_initialRootClaimData_succeeds() (gas: 17669)
-FaultDisputeGame_Test:test_move_clockCorrectness_succeeds() (gas: 416029)
-FaultDisputeGame_Test:test_move_clockTimeExceeded_reverts() (gas: 26399)
+FaultDisputeGame_Test:test_initialRootClaimData_succeeds() (gas: 17624)
+FaultDisputeGame_Test:test_move_clockCorrectness_succeeds() (gas: 419180)
+FaultDisputeGame_Test:test_move_clockTimeExceeded_reverts() (gas: 26421)
 FaultDisputeGame_Test:test_move_defendRoot_reverts() (gas: 13360)
-FaultDisputeGame_Test:test_move_duplicateClaim_reverts() (gas: 103254)
-FaultDisputeGame_Test:test_move_gameDepthExceeded_reverts() (gas: 408148)
-FaultDisputeGame_Test:test_move_gameNotInProgress_reverts() (gas: 10968)
-FaultDisputeGame_Test:test_move_nonExistentParent_reverts() (gas: 24655)
-FaultDisputeGame_Test:test_move_simpleAttack_succeeds() (gas: 107356)
-FaultDisputeGame_Test:test_resolve_challengeContested_succeeds() (gas: 224820)
+FaultDisputeGame_Test:test_move_duplicateClaim_reverts() (gas: 104120)
+FaultDisputeGame_Test:test_move_gameDepthExceeded_reverts() (gas: 411546)
+FaultDisputeGame_Test:test_move_gameNotInProgress_reverts() (gas: 11012)
+FaultDisputeGame_Test:test_move_nonExistentParent_reverts() (gas: 24677)
+FaultDisputeGame_Test:test_move_simpleAttack_succeeds() (gas: 108110)
+FaultDisputeGame_Test:test_resolve_challengeContested_succeeds() (gas: 226511)
 FaultDisputeGame_Test:test_resolve_notInProgress_reverts() (gas: 9657)
-FaultDisputeGame_Test:test_resolve_rootContested_succeeds() (gas: 109773)
-FaultDisputeGame_Test:test_resolve_rootUncontestedClockNotExpired_succeeds() (gas: 21434)
-FaultDisputeGame_Test:test_resolve_rootUncontested_succeeds() (gas: 27263)
-FaultDisputeGame_Test:test_resolve_teamDeathmatch_succeeds() (gas: 395502)
+FaultDisputeGame_Test:test_resolve_rootContested_succeeds() (gas: 110642)
+FaultDisputeGame_Test:test_resolve_rootUncontestedClockNotExpired_succeeds() (gas: 21437)
+FaultDisputeGame_Test:test_resolve_rootUncontested_succeeds() (gas: 27288)
+FaultDisputeGame_Test:test_resolve_teamDeathmatch_succeeds() (gas: 398859)
 FaultDisputeGame_Test:test_rootClaim_succeeds() (gas: 8225)
 FeeVault_Test:test_constructor_succeeds() (gas: 18185)
 GasBenchMark_L1CrossDomainMessenger:test_sendMessage_benchmark_0() (gas: 352113)
@@ -437,9 +437,11 @@ OptimistTest:test_tokenURI_returnsCorrectTokenURI_succeeds() (gas: 195908)
 OptimistTest:test_transferFrom_soulbound_reverts() (gas: 75512)
 PostSherlockL1:test_script_succeeds() (gas: 3078)
 PostSherlockL2:test_script_succeeds() (gas: 3078)
-PreimageOracle_Test:test_computePreimageKey_succeeds() (gas: 6242)
-PreimageOracle_Test:test_loadKeccak256PreimagePart_outOfBoundsOffset_reverts() (gas: 9005)
-PreimageOracle_Test:test_loadKeccak256PreimagePart_succeeds() (gas: 77502)
+PreimageOracle_Test:test_keccak256PreimageKey_succeeds() (gas: 319)
+PreimageOracle_Test:test_loadKeccak256PreimagePart_outOfBoundsOffset_reverts() (gas: 8993)
+PreimageOracle_Test:test_loadKeccak256PreimagePart_succeeds() (gas: 76098)
+PreimageOracle_Test:test_loadLocalData_onePart_succeeds() (gas: 75840)
+PreimageOracle_Test:test_loadLocalData_outOfBoundsOffset_reverts() (gas: 8803)
 ProxyAdmin_Test:test_chugsplashChangeProxyAdmin_succeeds() (gas: 35586)
 ProxyAdmin_Test:test_chugsplashGetProxyAdmin_succeeds() (gas: 15675)
 ProxyAdmin_Test:test_chugsplashGetProxyImplementation_succeeds() (gas: 51084)

packages/contracts-bedrock/scripts/Deploy.s.sol

@@ -698,7 +698,8 @@ contract Deploy is Deployer {
                     _absolutePrestate: absolutePrestate,
                     _maxGameDepth: cfg.faultGameMaxDepth(),
                     _gameDuration: Duration.wrap(uint64(cfg.faultGameMaxDuration())),
-                    _vm: faultVm
+                    _vm: faultVm,
+                    _l2oo: L2OutputOracle(mustGetAddress("L2OutputOracleProxy"))
                 }));
                 console.log("DisputeGameFactory: set `FaultDisputeGame` implementation");
             }

packages/contracts-bedrock/semver-lock.json

@@ -14,6 +14,7 @@
   "src/L2/L2StandardBridge.sol": "0x8ee5257e03ae4ba8555d9f7d13374c8a388315d62c16107bb4cadd450bfeb3d3",
   "src/L2/L2ToL1MessagePasser.sol": "0x7e35c3c4f1dd3d131dd71db07676301f7c477f02b6d6bf0ec468ecf2bed8325b",
   "src/L2/SequencerFeeVault.sol": "0x17b30ccaed8b8dbe965c892cb8aae7f594fb4a87e0edd3ca6cd8f94559b86df9",
+  "src/dispute/FaultDisputeGame.sol": "0xb36f6456d74a9ee93df97bb6d5a554dcb531d730e6e2b10dd442897875f2ca81",
   "src/legacy/DeployerWhitelist.sol": "0x47277d9c8409d517501d172db6697d55090d3d3a9e4bb2b1adea83471d793b6b",
   "src/legacy/L1BlockNumber.sol": "0x1a1690b8b5ab53cf2b5c8e85fb86028b4078ae656286ae482cabe68374334f2a",
   "src/legacy/LegacyMessagePasser.sol": "0xc7f42e6165507b4c50a5169a950f66602e6b4b8cff17f5d95994e121abb18390",

packages/contracts-bedrock/src/cannon/MIPS.sol

 // SPDX-License-Identifier: MIT
-pragma solidity 0.7.6;
+pragma solidity 0.8.15;
 
 import { IPreimageOracle } from "./interfaces/IPreimageOracle.sol";
+import { PreimageKeyLib } from "./PreimageKeyLib.sol";
 
 /// @title MIPS
 /// @notice The MIPS contract emulates a single MIPS instruction.
@@ -57,11 +58,13 @@ contract MIPS {
 
     /// @notice Extends the value leftwards with its most significant bit (sign extension).
     function SE(uint32 _dat, uint32 _idx) internal pure returns (uint32) {
+        unchecked {
             bool isSigned = (_dat >> (_idx - 1)) != 0;
             uint256 signed = ((1 << (32 - _idx)) - 1) << _idx;
             uint256 mask = (1 << _idx) - 1;
             return uint32(_dat & mask | (isSigned ? signed : 0));
         }
+    }
 
     /// @notice Computes the hash of the MIPS state.
     /// @return out_ The hash of the MIPS state.
@@ -109,11 +112,11 @@ contract MIPS {
             // Compute the hash of the resulting MIPS state
             out_ := keccak256(start, sub(to, start))
         }
-        return out_;
     }
 
     /// @notice Handles a syscall.
     function handleSyscall() internal returns (bytes32 out_) {
+        unchecked {
             // Load state from memory
             State memory state;
             assembly {
@@ -168,7 +171,12 @@ contract MIPS {
                 else if (a0 == FD_PREIMAGE_READ) {
                     // verify proof 1 is correct, and get the existing memory.
                     uint32 mem = readMem(a1 & 0xFFffFFfc, 1); // mask the addr to align it to 4 bytes
-                (bytes32 dat, uint256 datLen) = oracle.readPreimage(state.preimageKey, state.preimageOffset);
+                    bytes32 preimageKey = state.preimageKey;
+                    // If the preimage key is a local key, localize it in the context of the caller.
+                    if (uint8(preimageKey[0]) == 1) {
+                        preimageKey = PreimageKeyLib.localize(preimageKey);
+                    }
+                    (bytes32 dat, uint256 datLen) = oracle.readPreimage(preimageKey, state.preimageOffset);
 
                     // Transform data for writing to memory
                     // We use assembly for more precise ops, and no var count limit
@@ -264,6 +272,7 @@ contract MIPS {
 
             out_ = outputState();
         }
+    }
 
     /// @notice Handles a branch instruction, updating the MIPS state PC where needed.
     /// @param _opcode The opcode of the branch instruction.
@@ -272,6 +281,7 @@ contract MIPS {
     /// @param _rs The register to be compared with the branch register.
     /// @return out_ The hashed MIPS state.
     function handleBranch(uint32 _opcode, uint32 _insn, uint32 _rtReg, uint32 _rs) internal returns (bytes32 out_) {
+        unchecked {
             // Load state from memory
             State memory state;
             assembly {
@@ -280,6 +290,10 @@ contract MIPS {
 
             bool shouldBranch = false;
 
+            if (state.nextPC != state.pc+4) {
+                revert("branch in delay slot");
+            }
+
             // beq/bne: Branch on equal / not equal
             if (_opcode == 4 || _opcode == 5) {
                 uint32 rt = state.registers[_rtReg];
@@ -322,6 +336,7 @@ contract MIPS {
             // Return the hash of the resulting state
             out_ = outputState();
         }
+    }
 
     /// @notice Handles HI and LO register instructions.
     /// @param _func The function code of the instruction.
@@ -330,6 +345,7 @@ contract MIPS {
     /// @param _storeReg The register to store the result in.
     /// @return out_ The hash of the resulting MIPS state.
     function handleHiLo(uint32 _func, uint32 _rs, uint32 _rt, uint32 _storeReg) internal returns (bytes32 out_) {
+        unchecked {
             // Load state from memory
             State memory state;
             assembly {
@@ -393,18 +409,24 @@ contract MIPS {
             // Return the hash of the resulting state
             out_ = outputState();
         }
+    }
 
     /// @notice Handles a jump instruction, updating the MIPS state PC where needed.
     /// @param _linkReg The register to store the link to the instruction after the delay slot instruction.
     /// @param _dest The destination to jump to.
     /// @return out_ The hashed MIPS state.
     function handleJump(uint32 _linkReg, uint32 _dest) internal returns (bytes32 out_) {
+        unchecked {
             // Load state from memory.
             State memory state;
             assembly {
                 state := 0x80
             }
 
+            if (state.nextPC != state.pc+4) {
+                revert("jump in delay slot");
+            }
+
             // Update the next PC to the jump destination.
             uint32 prevPC = state.pc;
             state.pc = state.nextPC;
@@ -418,6 +440,7 @@ contract MIPS {
             // Return the hash of the resulting state.
             out_ = outputState();
         }
+    }
 
     /// @notice Handles a storing a value into a register.
     /// @param _storeReg The register to store the value into.
@@ -425,6 +448,7 @@ contract MIPS {
     /// @param _conditional Whether or not the store is conditional.
     /// @return out_ The hashed MIPS state.
     function handleRd(uint32 _storeReg, uint32 _val, bool _conditional) internal returns (bytes32 out_) {
+        unchecked {
             // Load state from memory.
             State memory state;
             assembly {
@@ -446,11 +470,13 @@ contract MIPS {
             // Return the hash of the resulting state.
             out_ = outputState();
         }
+    }
 
     /// @notice Computes the offset of the proof in the calldata.
     /// @param _proofIndex The index of the proof in the calldata.
     /// @return offset_ The offset of the proof in the calldata.
     function proofOffset(uint8 _proofIndex) internal pure returns (uint256 offset_) {
+        unchecked {
             // A proof of 32 bit memory, with 32-byte leaf values, is (32-5)=27 bytes32 entries.
             // And the leaf value itself needs to be encoded as well. And proof.offset == 358
             offset_ = 358 + (uint256(_proofIndex) * (28 * 32));
@@ -459,12 +485,14 @@ contract MIPS {
             require(s >= (offset_ + 28 * 32), "check that there is enough calldata");
             return offset_;
         }
+    }
 
     /// @notice Reads a 32-bit value from memory.
     /// @param _addr The address to read from.
     /// @param _proofIndex The index of the proof in the calldata.
     /// @return out_ The hashed MIPS state.
     function readMem(uint32 _addr, uint8 _proofIndex) internal pure returns (uint32 out_) {
+        unchecked {
             // Compute the offset of the proof in the calldata.
             uint256 offset = proofOffset(_proofIndex);
 
@@ -514,6 +542,7 @@ contract MIPS {
                 out_ := and(shr(shamt, leaf), 0xFFffFFff)
             }
         }
+    }
 
     /// @notice Writes a 32-bit value to memory.
     ///         This function first overwrites the part of the leaf.
@@ -522,6 +551,7 @@ contract MIPS {
     /// @param _proofIndex The index of the proof in the calldata.
     /// @param _val The value to write.
     function writeMem(uint32 _addr, uint8 _proofIndex, uint32 _val) internal pure {
+        unchecked {
             // Compute the offset of the proof in the calldata.
             uint256 offset = proofOffset(_proofIndex);
 
@@ -565,10 +595,12 @@ contract MIPS {
                 mstore(0x80, node)
             }
         }
+    }
 
     /// @notice Executes a single step of the vm.
     ///         Will revert if any required input state is missing.
     function step(bytes calldata stateData, bytes calldata proof) public returns (bytes32) {
+        unchecked {
             State memory state;
 
             // Packed calldata is ~6 times smaller than state size
@@ -728,9 +760,11 @@ contract MIPS {
             // write back the value to destination register
             return handleRd(rdReg, val, true);
         }
+    }
 
     /// @notice Execute an instruction.
     function execute(uint32 insn, uint32 rs, uint32 rt, uint32 mem) internal pure returns (uint32) {
+        unchecked {
             uint32 opcode = insn >> 26;    // 6-bits
             uint32 func = insn & 0x3f; // 6-bits
             // TODO(CLI-4136): deref the immed into a register
@@ -915,4 +949,5 @@ contract MIPS {
 
             revert("invalid instruction");
         }
+    }
 }

packages/contracts-bedrock/src/cannon/PreimageKeyLib.sol

+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.15;
+
+/// @title PreimageKeyLib
+/// @notice Shared utilities for localizing local keys in the preimage oracle.
+library PreimageKeyLib {
+    /// @notice Generates a context-specific local key for the given local data identifier.
+    /// @dev See `localize` for a description of the localization operation.
+    /// @param _ident The identifier of the local data. [0, 32) bytes in size.
+    /// @return key_ The context-specific local key.
+    function localizeIdent(uint256 _ident) internal view returns (bytes32 key_) {
+        assembly {
+            // Set the type byte in the given identifier to `1` (Local). We only care about
+            // the [1, 32) bytes in this value.
+            key_ := or(shl(248, 1), and(_ident, not(shl(248, 0xFF))))
+        }
+        key_ = localize(key_);
+    }
+
+    /// @notice Localizes a given local data key for the caller's context.
+    /// @dev The localization operation is defined as:
+    ///      localize(k) = H(k .. sender) & ~(0xFF << 248) | (0x01 << 248)
+    ///      where H is the Keccak-256 hash function.
+    /// @param _key The local data key to localize.
+    /// @return localizedKey_ The localized local data key.
+    function localize(bytes32 _key) internal view returns (bytes32 localizedKey_) {
+        assembly {
+            // Store the local data key and caller next to each other in memory for hashing.
+            mstore(0, _key)
+            mstore(0x20, caller())
+            // Localize the key with the above `localize` operation.
+            localizedKey_ := or(and(keccak256(0, 0x40), not(shl(248, 0xFF))), shl(248, 1))
+        }
+    }
+
+    /// @notice Computes and returns the key for a global keccak pre-image.
+    /// @param _preimage The pre-image.
+    /// @return key_ The pre-image key.
+    function keccak256PreimageKey(bytes memory _preimage) internal pure returns (bytes32 key_) {
+        assembly {
+            // Grab the size of the `_preimage`
+            let size := mload(_preimage)
+
+            // Compute the pre-image keccak256 hash (aka the pre-image key)
+            let h := keccak256(add(_preimage, 0x20), size)
+
+            // Mask out prefix byte, replace with type 2 byte
+            key_ := or(and(h, not(shl(248, 0xFF))), shl(248, 2))
+        }
+    }
+}

packages/contracts-bedrock/src/cannon/PreimageOracle.sol

 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.15;
+pragma solidity 0.8.15;
+
+import { IPreimageOracle } from "./interfaces/IPreimageOracle.sol";
+import { PreimageKeyLib } from "./PreimageKeyLib.sol";
+import "./libraries/CannonErrors.sol";
 
 /// @title PreimageOracle
 /// @notice A contract for storing permissioned pre-images.
-contract PreimageOracle {
+contract PreimageOracle is IPreimageOracle {
     /// @notice Mapping of pre-image keys to pre-image lengths.
     mapping(bytes32 => uint256) public preimageLengths;
-
     /// @notice Mapping of pre-image keys to pre-image parts.
     mapping(bytes32 => mapping(uint256 => bytes32)) public preimageParts;
-
     /// @notice Mapping of pre-image keys to pre-image part offsets.
     mapping(bytes32 => mapping(uint256 => bool)) public preimagePartOk;
 
-    /// @notice Reads a pre-image from the oracle.
-    /// @param _key The key of the pre-image to read.
-    /// @param _offset The offset of the pre-image to read.
-    /// @return dat_ The pre-image data.
-    /// @return datLen_ The length of the pre-image data.
+    /// @inheritdoc IPreimageOracle
     function readPreimage(bytes32 _key, uint256 _offset)
         external
         view
@@ -37,11 +35,11 @@ contract PreimageOracle {
         dat_ = preimageParts[_key][_offset];
     }
 
-    // TODO(CLI-4104):
-    // we need to mix-in the ID of the dispute for local-type keys to avoid collisions,
-    // and restrict local pre-image insertion to the dispute-managing contract.
-    // For now we permit anyone to write any pre-image unchecked, to make testing easy.
-    // This method is DANGEROUS. And NOT FOR PRODUCTION.
+    /// TODO(CLI-4104):
+    /// we need to mix-in the ID of the dispute for local-type keys to avoid collisions,
+    /// and restrict local pre-image insertion to the dispute-managing contract.
+    /// For now we permit anyone to write any pre-image unchecked, to make testing easy.
+    /// This method is DANGEROUS. And NOT FOR PRODUCTION.
     function cheat(
         uint256 partOffset,
         bytes32 key,
@@ -53,37 +51,43 @@ contract PreimageOracle {
         preimageLengths[key] = size;
     }
 
-    /// @notice Computes and returns the key for a pre-image.
-    /// @param _preimage The pre-image.
-    /// @return key_ The pre-image key.
-    function computePreimageKey(bytes calldata _preimage) external pure returns (bytes32 key_) {
-        uint256 size;
-        assembly {
-            size := calldataload(0x24)
-
-            // Leave slots 0x40 and 0x60 untouched,
-            // and everything after as scratch-memory.
-            let ptr := 0x80
+    /// @inheritdoc IPreimageOracle
+    function loadLocalData(
+        uint256 _ident,
+        bytes32 _word,
+        uint256 _size,
+        uint256 _partOffset
+    ) external returns (bytes32 key_) {
+        // Compute the localized key from the given local identifier.
+        key_ = PreimageKeyLib.localizeIdent(_ident);
 
-            // Store size as a big-endian uint64 at the start of pre-image
-            mstore(ptr, shl(192, size))
-            ptr := add(ptr, 8)
+        // Revert if the given part offset is not within bounds.
+        if (_partOffset > _size + 8 || _size > 32) {
+            revert PartOffsetOOB();
+        }
 
-            // Copy preimage payload into memory so we can hash and read it.
-            calldatacopy(ptr, _preimage.offset, size)
+        // Prepare the local data part at the given offset
+        bytes32 part;
+        assembly {
+            // Clean the memory in [0x20, 0x40)
+            mstore(0x20, 0x00)
 
-            // Compute the pre-image keccak256 hash (aka the pre-image key)
-            let h := keccak256(ptr, size)
+            // Store the full local data in scratch space.
+            mstore(0x00, shl(192, _size))
+            mstore(0x08, _word)
 
-            // Mask out prefix byte, replace with type 2 byte
-            key_ := or(and(h, not(shl(248, 0xFF))), shl(248, 2))
+            // Prepare the local data part at the requested offset.
+            part := mload(_partOffset)
         }
+
+        // Store the first part with `_partOffset`.
+        preimagePartOk[key_][_partOffset] = true;
+        preimageParts[key_][_partOffset] = part;
+        // Assign the length of the preimage at the localized key.
+        preimageLengths[key_] = _size;
     }
 
-    /// @notice Prepares a pre-image to be read by keccak256 key, starting at
-    ///         the given offset and up to 32 bytes (clipped at pre-image length, if out of data).
-    /// @param _partOffset The offset of the pre-image to read.
-    /// @param _preimage The preimage data.
+    /// @inheritdoc IPreimageOracle
     function loadKeccak256PreimagePart(uint256 _partOffset, bytes calldata _preimage) external {
         uint256 size;
         bytes32 key;
@@ -94,7 +98,10 @@ contract PreimageOracle {
 
             // revert if part offset > size+8 (i.e. parts must be within bounds)
             if gt(_partOffset, add(size, 8)) {
-                revert(0, 0)
+                // Store "PartOffsetOOB()"
+                mstore(0, 0xfe254987)
+                // Revert with "PartOffsetOOB()"
+                revert(0x1c, 4)
             }
             // we leave solidity slots 0x40 and 0x60 untouched,
             // and everything after as scratch-memory.

packages/contracts-bedrock/src/cannon/interfaces/IPreimageOracle.sol

 // SPDX-License-Identifier: MIT
-pragma solidity 0.7.6;
+pragma solidity 0.8.15;
 
 /// @title IPreimageOracle
 /// @notice Interface for a preimage oracle.
@@ -14,10 +14,31 @@ interface IPreimageOracle {
         view
         returns (bytes32 dat_, uint256 datLen_);
 
-    /// @notice Computes and returns the key for a pre-image.
-    /// @param _preimage The pre-image.
-    /// @return key_ The pre-image key.
-    function computePreimageKey(bytes calldata _preimage) external pure returns (bytes32 key_);
+    /// @notice Loads of local data part into the preimage oracle.
+    /// @param _ident The identifier of the local data.
+    /// @param _word The local data word.
+    /// @param _size The number of bytes in `_word` to load.
+    /// @param _partOffset The offset of the local data part to write to the oracle.
+    /// @dev The local data parts are loaded into the preimage oracle under the context
+    ///      of the caller - no other account can write to the caller's context
+    ///      specific data.
+    ///
+    ///      There are 5 local data identifiers:
+    ///      ┌────────────┬────────────────────────┐
+    ///      │ Identifier │      Data              │
+    ///      ├────────────┼────────────────────────┤
+    ///      │          1 │ L1 Head Hash (bytes32) │
+    ///      │          2 │ Output Root (bytes32)  │
+    ///      │          3 │ Root Claim (bytes32)   │
+    ///      │          4 │ L2 Block Number (u64)  │
+    ///      │          5 │ Chain ID (u64)         │
+    ///      └────────────┴────────────────────────┘
+    function loadLocalData(
+        uint256 _ident,
+        bytes32 _word,
+        uint256 _size,
+        uint256 _partOffset
+    ) external returns (bytes32 key_);
 
     /// @notice Prepares a preimage to be read by keccak256 key, starting at
     ///         the given offset and up to 32 bytes (clipped at preimage length, if out of data).

packages/contracts-bedrock/src/cannon/libraries/CannonErrors.sol

+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.15;
+
+/// @notice Thrown when a passed part offset is out of bounds.
+error PartOffsetOOB();

packages/contracts-bedrock/src/dispute/FaultDisputeGame.sol

@@ -5,9 +5,11 @@ import { IDisputeGame } from "./interfaces/IDisputeGame.sol";
 import { IFaultDisputeGame } from "./interfaces/IFaultDisputeGame.sol";
 import { IInitializable } from "./interfaces/IInitializable.sol";
 import { IBondManager } from "./interfaces/IBondManager.sol";
-import { IBigStepper } from "./interfaces/IBigStepper.sol";
+import { IBigStepper, IPreimageOracle } from "./interfaces/IBigStepper.sol";
+import { L2OutputOracle } from "../L1/L2OutputOracle.sol";
 
 import { Clone } from "../libraries/Clone.sol";
+import { Types } from "../libraries/Types.sol";
 import { Semver } from "../universal/Semver.sol";
 import { LibHashing } from "./lib/LibHashing.sol";
 import { LibPosition } from "./lib/LibPosition.sol";
@@ -33,9 +35,12 @@ contract FaultDisputeGame is IFaultDisputeGame, Clone, Semver {
     /// @notice The duration of the game.
     Duration public immutable GAME_DURATION;
 
-    /// @notice A hypervisor that performs single instruction steps on a fault proof program trace.
+    /// @notice An onchain VM that performs single instruction steps on a fault proof program trace.
     IBigStepper public immutable VM;
 
+    /// @notice The trusted L2OutputOracle contract.
+    L2OutputOracle public immutable L2_OUTPUT_ORACLE;
+
     /// @notice The root claim's position is always at gindex 1.
     Position internal constant ROOT_POSITION = Position.wrap(1);
 
@@ -48,6 +53,9 @@ contract FaultDisputeGame is IFaultDisputeGame, Clone, Semver {
     /// @inheritdoc IDisputeGame
     IBondManager public bondManager;
 
+    /// @inheritdoc IFaultDisputeGame
+    Hash public l1Head;
+
     /// @notice An append-only array of all claims made during the dispute game.
     ClaimData[] public claimData;
 
@@ -55,16 +63,24 @@ contract FaultDisputeGame is IFaultDisputeGame, Clone, Semver {
     mapping(ClaimHash => bool) internal claims;
 
     /// @param _absolutePrestate The absolute prestate of the instruction trace.
+    /// @param _maxGameDepth The maximum depth of bisection.
+    /// @param _gameDuration The duration of the game.
+    /// @param _vm An onchain VM that performs single instruction steps on a fault proof program
+    ///            trace.
+    /// @param _l2oo The trusted L2OutputOracle contract.
+    /// @custom:semver 0.0.4
     constructor(
         Claim _absolutePrestate,
         uint256 _maxGameDepth,
         Duration _gameDuration,
-        IBigStepper _vm
-    ) Semver(0, 0, 3) {
+        IBigStepper _vm,
+        L2OutputOracle _l2oo
+    ) Semver(0, 0, 4) {
         ABSOLUTE_PRESTATE = _absolutePrestate;
         MAX_GAME_DEPTH = _maxGameDepth;
         GAME_DURATION = _gameDuration;
         VM = _vm;
+        L2_OUTPUT_ORACLE = _l2oo;
     }
 
     ////////////////////////////////////////////////////////////////
@@ -241,6 +257,38 @@ contract FaultDisputeGame is IFaultDisputeGame, Clone, Semver {
         move(_parentIndex, _claim, false);
     }
 
+    /// @inheritdoc IFaultDisputeGame
+    function addLocalData(uint256 _ident, uint256 _partOffset) external {
+        // INVARIANT: Local data can only be added if the game is currently in progress.
+        if (status != GameStatus.IN_PROGRESS) revert GameNotInProgress();
+
+        IPreimageOracle oracle = VM.oracle();
+        if (_ident == 1) {
+            // Load the L1 head hash into the game's local context in the preimage oracle.
+            oracle.loadLocalData(_ident, Hash.unwrap(l1Head), 32, _partOffset);
+        } else if (_ident == 2) {
+            // Load the earliest output root that commits to the passed L2 block number
+            // into the game's local context in the preimage oracle.
+            Types.OutputProposal memory proposal = L2_OUTPUT_ORACLE.getL2OutputAfter(
+                l2BlockNumber()
+            );
+            oracle.loadLocalData(_ident, proposal.outputRoot, 32, _partOffset);
+        } else if (_ident == 3) {
+            // Load the root claim into the game's local context in the preimage oracle.
+            oracle.loadLocalData(_ident, Claim.unwrap(rootClaim()), 32, _partOffset);
+        } else if (_ident == 4) {
+            // Load the L2 block number into the game's local context in the preimage oracle.
+            // The L2 block number is stored as a big-endian uint64 in the upper 8 bytes of the
+            // passed word.
+            oracle.loadLocalData(_ident, bytes32(l2BlockNumber() << 192), 8, _partOffset);
+        } else if (_ident == 5) {
+            // Load the chain ID into the game's local context in the preimage oracle.
+            // The chain ID is stored as a big-endian uint64 in the upper 8 bytes of the
+            // passed word.
+            oracle.loadLocalData(_ident, bytes32(block.chainid << 192), 8, _partOffset);
+        }
+    }
+
     /// @inheritdoc IFaultDisputeGame
     function l2BlockNumber() public pure returns (uint256 l2BlockNumber_) {
         l2BlockNumber_ = _getArgUint256(0x20);
@@ -337,8 +385,6 @@ contract FaultDisputeGame is IFaultDisputeGame, Clone, Semver {
     /// @inheritdoc IDisputeGame
     function extraData() public pure returns (bytes memory extraData_) {
         // The extra data starts at the second word within the cwia calldata.
-        // TODO: What data do we need to pass along to this contract from the factory?
-        //       Block hash, preimage data, etc.?
         extraData_ = _getArgDynBytes(0x20, 0x20);
     }
 
@@ -378,6 +424,9 @@ contract FaultDisputeGame is IFaultDisputeGame, Clone, Semver {
                 countered: false
             })
         );
+
+        // Set the L1 head hash at the time of the game's creation.
+        l1Head = Hash.wrap(blockhash(block.number - 1));
     }
 
     /// @notice Returns the length of the `claimData` array.

packages/contracts-bedrock/src/dispute/interfaces/IBigStepper.sol

 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.15;
 
+import { IPreimageOracle } from "../../cannon/interfaces/IPreimageOracle.sol";
+
 /// @title IBigStepper
 /// @notice An interface for a contract with a state transition function that
 ///         will accept a pre state and return a post state.
@@ -31,4 +33,7 @@ interface IBigStepper {
     function step(bytes calldata _stateData, bytes calldata _proof)
         external
         returns (bytes32 postState_);
+
+    /// @notice Returns the preimage oracle used by the stepper.
+    function oracle() external view returns (IPreimageOracle oracle_);
 }

packages/contracts-bedrock/src/dispute/interfaces/IDisputeGame.sol

@@ -22,19 +22,18 @@ interface IDisputeGame is IInitializable {
     function status() external view returns (GameStatus status_);
 
     /// @notice Getter for the game type.
-    /// @dev `clones-with-immutable-args` argument #1
     /// @dev The reference impl should be entirely different depending on the type (fault, validity)
     ///      i.e. The game type should indicate the security model.
     /// @return gameType_ The type of proof system being used.
     function gameType() external pure returns (GameType gameType_);
 
     /// @notice Getter for the root claim.
-    /// @dev `clones-with-immutable-args` argument #2
+    /// @dev `clones-with-immutable-args` argument #1
     /// @return rootClaim_ The root claim of the DisputeGame.
     function rootClaim() external pure returns (Claim rootClaim_);
 
     /// @notice Getter for the extra data.
-    /// @dev `clones-with-immutable-args` argument #3
+    /// @dev `clones-with-immutable-args` argument #2
     /// @return extraData_ Any extra data supplied to the dispute game contract by the creator.
     function extraData() external pure returns (bytes memory extraData_);
 

packages/contracts-bedrock/src/dispute/interfaces/IFaultDisputeGame.sol

@@ -53,6 +53,14 @@ interface IFaultDisputeGame is IDisputeGame {
         bytes calldata _proof
     ) external;
 
+    /// @notice Posts the requested local data to the VM's `PreimageOralce`.
+    /// @param _ident The local identifier of the data to post.
+    /// @param _partOffset The offset of the data to post.
+    function addLocalData(uint256 _ident, uint256 _partOffset) external;
+
+    /// @notice Returns the L1 block hash at the time of the game's creation.
+    function l1Head() external view returns (Hash l1Head_);
+
     /// @notice The l2BlockNumber that the `rootClaim` commits to. The trace being bisected within
     ///         the game is from `l2BlockNumber - 1` -> `l2BlockNumber`.
     /// @return l2BlockNumber_ The l2BlockNumber that the `rootClaim` commits to.

packages/contracts-bedrock/src/periphery/AssetReceiver.sol

@@ -64,6 +64,7 @@ contract AssetReceiver is Transactor {
     function withdrawETH(address payable _to, uint256 _amount) public onlyOwner {
         // slither-disable-next-line reentrancy-unlimited-gas
         (bool success, ) = _to.call{ value: _amount }("");
+        success; // Suppress warning; We ignore the low-level call result.
         emit WithdrewETH(msg.sender, _to, _amount);
     }
 

packages/contracts-bedrock/test/FaultDisputeGame.t.sol

@@ -4,14 +4,15 @@ pragma solidity ^0.8.15;
 import { Test } from "forge-std/Test.sol";
 import { Vm } from "forge-std/Vm.sol";
 import { DisputeGameFactory_Init } from "./DisputeGameFactory.t.sol";
-import { DisputeGameFactory } from "../src/dispute/DisputeGameFactory.sol";
-import { FaultDisputeGame } from "../src/dispute/FaultDisputeGame.sol";
+import { DisputeGameFactory } from "src/dispute/DisputeGameFactory.sol";
+import { FaultDisputeGame } from "src/dispute/FaultDisputeGame.sol";
+import { L2OutputOracle } from "src/L1/L2OutputOracle.sol";
 
-import "../src/libraries/DisputeTypes.sol";
-import "../src/libraries/DisputeErrors.sol";
-import { LibClock } from "../src/dispute/lib/LibClock.sol";
-import { LibPosition } from "../src/dispute/lib/LibPosition.sol";
-import { IBigStepper } from "../src/dispute/interfaces/IBigStepper.sol";
+import "src/libraries/DisputeTypes.sol";
+import "src/libraries/DisputeErrors.sol";
+import { LibClock } from "src/dispute/lib/LibClock.sol";
+import { LibPosition } from "src/dispute/lib/LibPosition.sol";
+import { IBigStepper, IPreimageOracle } from "src/dispute/interfaces/IBigStepper.sol";
 
 contract FaultDisputeGame_Init is DisputeGameFactory_Init {
     /// @dev The extra data passed to the game for initialization.
@@ -28,12 +29,14 @@ contract FaultDisputeGame_Init is DisputeGameFactory_Init {
 
     function init(Claim rootClaim, Claim absolutePrestate) public {
         super.setUp();
+
         // Deploy an implementation of the fault game
         gameImpl = new FaultDisputeGame(
             absolutePrestate,
             4,
             Duration.wrap(7 days),
-            new AlphabetVM(absolutePrestate)
+            new AlphabetVM(absolutePrestate),
+            L2OutputOracle(deployNoop())
         );
         // Register the game implementation with the factory.
         factory.setImplementation(GAME_TYPE, gameImpl);
@@ -889,9 +892,11 @@ contract VariableDivergentPlayer is GamePlayer {
 
 contract AlphabetVM is IBigStepper {
     Claim internal immutable ABSOLUTE_PRESTATE;
+    IPreimageOracle public oracle;
 
     constructor(Claim _absolutePrestate) {
         ABSOLUTE_PRESTATE = _absolutePrestate;
+        oracle = IPreimageOracle(deployNoop());
     }
 
     /// @inheritdoc IBigStepper
@@ -915,3 +920,16 @@ contract AlphabetVM is IBigStepper {
         postState_ = keccak256(abi.encode(traceIndex, claim + 1));
     }
 }
+
+////////////////////////////////////////////////////////////////
+//                          HELPERS                           //
+////////////////////////////////////////////////////////////////
+
+/// @notice Deploys a noop contract.
+function deployNoop() returns (address noop_) {
+    assembly {
+        mstore(0x00, 0x60016000F3)
+        let size := 5
+        noop_ := create(0, sub(0x20, size), size)
+    }
+}

packages/contracts-bedrock/test/PreimageOracle.t.sol

 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.15;
+pragma solidity 0.8.15;
 
 import { Test } from "forge-std/Test.sol";
 
-import { PreimageOracle } from "../src/cannon/PreimageOracle.sol";
+import { PreimageOracle } from "src/cannon/PreimageOracle.sol";
+import { PreimageKeyLib } from "src/cannon/PreimageKeyLib.sol";
+import "src/cannon/libraries/CannonErrors.sol";
 
 contract PreimageOracle_Test is Test {
     PreimageOracle oracle;
@@ -15,18 +17,76 @@ contract PreimageOracle_Test is Test {
     }
 
     /// @notice Test the pre-image key computation with a known pre-image.
-    function test_computePreimageKey_succeeds() public {
+    function test_keccak256PreimageKey_succeeds() public {
         bytes memory preimage = hex"deadbeef";
-        bytes32 key = oracle.computePreimageKey(preimage);
+        bytes32 key = PreimageKeyLib.keccak256PreimageKey(preimage);
         bytes32 known = 0x02fd4e189132273036449fc9e11198c739161b4c0116a9a2dccdfa1c492006f1;
         assertEq(key, known);
     }
 
+    /// @notice Tests that context-specific data [0, 24] bytes in length can be loaded correctly.
+    function test_loadLocalData_onePart_succeeds() public {
+        uint256 ident = 1;
+        bytes32 word = bytes32(uint256(0xdeadbeef) << 224);
+        uint8 size = 4;
+        uint8 partOffset = 0;
+
+        // Load the local data into the preimage oracle under the test contract's context.
+        bytes32 contextKey = oracle.loadLocalData(ident, word, size, partOffset);
+
+        // Validate that the pre-image part is set
+        bool ok = oracle.preimagePartOk(contextKey, partOffset);
+        assertTrue(ok);
+
+        // Validate the local data part
+        bytes32 expectedPart = 0x0000000000000004deadbeef0000000000000000000000000000000000000000;
+        assertEq(oracle.preimageParts(contextKey, partOffset), expectedPart);
+
+        // Validate the local data length
+        uint256 length = oracle.preimageLengths(contextKey);
+        assertEq(length, size);
+    }
+
+    /// @notice Tests that context-specific data [0, 32] bytes in length can be loaded correctly.
+    function testFuzz_loadLocalData_varyingLength_succeeds(
+        uint256 ident,
+        bytes32 word,
+        uint256 size,
+        uint256 partOffset
+    ) public {
+        // Bound the size to [0, 32]
+        size = bound(size, 0, 32);
+        // Bound the part offset to [0, size + 8]
+        partOffset = bound(partOffset, 0, size + 8);
+
+        // Load the local data into the preimage oracle under the test contract's context.
+        bytes32 contextKey = oracle.loadLocalData(ident, word, uint8(size), uint8(partOffset));
+
+        // Validate that the first local data part is set
+        bool ok = oracle.preimagePartOk(contextKey, partOffset);
+        assertTrue(ok);
+        // Validate the first local data part
+        bytes32 expectedPart;
+        assembly {
+            mstore(0x20, 0x00)
+
+            mstore(0x00, shl(192, size))
+            mstore(0x08, word)
+
+            expectedPart := mload(partOffset)
+        }
+        assertEq(oracle.preimageParts(contextKey, partOffset), expectedPart);
+
+        // Validate the local data length
+        uint256 length = oracle.preimageLengths(contextKey);
+        assertEq(length, size);
+    }
+
     /// @notice Tests that a pre-image is correctly set.
     function test_loadKeccak256PreimagePart_succeeds() public {
         // Set the pre-image
         bytes memory preimage = hex"deadbeef";
-        bytes32 key = oracle.computePreimageKey(preimage);
+        bytes32 key = PreimageKeyLib.keccak256PreimageKey(preimage);
         uint256 offset = 0;
         oracle.loadKeccak256PreimagePart(offset, preimage);
 
@@ -44,12 +104,21 @@ contract PreimageOracle_Test is Test {
         assertTrue(ok);
     }
 
+    /// @notice Tests that a pre-image cannot be set with an out-of-bounds offset.
+    function test_loadLocalData_outOfBoundsOffset_reverts() public {
+        bytes32 preimage = bytes32(uint256(0xdeadbeef));
+        uint256 offset = preimage.length + 9;
+
+        vm.expectRevert(PartOffsetOOB.selector);
+        oracle.loadLocalData(1, preimage, 32, offset);
+    }
+
     /// @notice Tests that a pre-image cannot be set with an out-of-bounds offset.
     function test_loadKeccak256PreimagePart_outOfBoundsOffset_reverts() public {
         bytes memory preimage = hex"deadbeef";
         uint256 offset = preimage.length + 9;
 
-        vm.expectRevert();
+        vm.expectRevert(PartOffsetOOB.selector);
         oracle.loadKeccak256PreimagePart(offset, preimage);
     }
 

specs/exec-engine.md

@@ -242,7 +242,7 @@ as the engine implementation can sync state faster through methods like [snap-sy
 ### Happy-path sync
 
 1. The rollup node informs the engine of the L2 chain head, unconditionally (part of regular node operation):
-   - [`engine_newPayloadV1`][engine_newPayloadV1] is called with latest L2 block derived from L1.
+   - [`engine_newPayloadV1`][engine_newPayloadV1] is called with latest L2 block received from P2P.
    - [`engine_forkchoiceUpdatedV1`][engine_forkchoiceUpdatedV1] is called with the current
      `unsafe`/`safe`/`finalized` L2 block hashes.
 2. The engine requests headers from peers, in reverse till the parent hash matches the local chain