mipsevm: fix lint issues

mipsevm/evm.go

@@ -32,6 +32,9 @@ func LoadContracts() (*Contracts, error) {
 		return nil, err
 	}
 	oracle, err := LoadContract("Oracle")
+	if err != nil {
+		return nil, err
+	}
 	return &Contracts{
 		MIPS:   mips,
 		Oracle: oracle,

mipsevm/unicorn.go

@@ -38,8 +38,6 @@ type UnicornState struct {
 	lastPreimageKey [32]byte
 	// offset we last read from, or max uint32 if nothing is read this step
 	lastPreimageOffset uint32
-
-	onStep func()
 }
 
 const (
@@ -239,8 +237,8 @@ func NewUnicornState(mu uc.Unicorn, state *State, po PreimageOracle, stdOut, std
 				v1 = MipsEINVAL // cmd not recognized by this kernel
 			}
 		}
-		mu.RegWrite(uc.MIPS_REG_V0, uint64(v0))
-		mu.RegWrite(uc.MIPS_REG_A3, uint64(v1))
+		_ = mu.RegWrite(uc.MIPS_REG_V0, uint64(v0))
+		_ = mu.RegWrite(uc.MIPS_REG_A3, uint64(v1))
 	}, 0, ^uint64(0))
 	if err != nil {
 		return nil, fmt.Errorf("failed to set up interrupt/syscall hook: %w", err)
@@ -358,6 +356,9 @@ func (m *UnicornState) Step(proof bool) (wit *StepWitness) {
 		Timeout: 0, // 0 to disable, value is in ms.
 		Count:   1,
 	})
+	if err != nil {
+		panic("failed to run unicorn")
+	}
 
 	if proof {
 		wit.memProof = append(wit.memProof, m.memProof[:]...)

mipsevm/unicorn_test.go

@@ -20,9 +20,10 @@ func TestUnicornDelaySlot(t *testing.T) {
 	require.NoError(t, mu.MemWrite(4, []byte{0x20, 0x09, 0x0a, 0xFF}), "addi $t1 $r0 0x0aff")
 	require.NoError(t, mu.MemWrite(32, []byte{0x20, 0x09, 0x0b, 0xFF}), "addi $t1 $r0 0x0bff")
 
-	mu.HookAdd(uc.HOOK_CODE, func(mu uc.Unicorn, addr uint64, size uint32) {
+	_, err = mu.HookAdd(uc.HOOK_CODE, func(mu uc.Unicorn, addr uint64, size uint32) {
 		t.Logf("addr: %08x", addr)
 	}, uint64(0), ^uint64(0))
+	require.NoError(t, err)
 	// stop at instruction in addr=4, the delay slot
 	require.NoError(t, mu.StartWithOptions(uint64(0), uint64(4), &uc.UcOptions{
 		Timeout: 0, // 0 to disable, value is in ms.