acpi: add VM-support for AML arithmetic opcodes

src/gopheros/device/acpi/aml/vm.go

@@ -18,6 +18,7 @@ var (
 	errCopyFailed              = &Error{message: "vmCopyObject: copy failed"}
 	errConversionFailed        = &Error{message: "vmConvert: conversion failed"}
 	errArgIndexOutOfBounds     = &Error{message: "vm: arg index out of bounds"}
+	errDivideByZero            = &Error{message: "vm: division by zero"}
 )
 
 // objRef is a pointer to an argument (local or global) or a named AML object.

src/gopheros/device/acpi/aml/vm_convert.go

@@ -167,7 +167,6 @@ func vmConvert(ctx *execContext, arg interface{}, toType valueType) (interface{}
 			return strconv.FormatUint(argAsInt, 16), nil
 		}
 	}
-
 	return nil, errConversionFailed
 }
 

src/gopheros/device/acpi/aml/vm_convert_test.go

@@ -284,6 +284,13 @@ func TestVMToIntArgs2(t *testing.T) {
 }
 
 func TestVMConvert(t *testing.T) {
+	vm := NewVM(nil, nil)
+	vm.populateJumpTable()
+
+	vm.jumpTable[0] = func(_ *execContext, ent Entity) *Error {
+		return &Error{message: "something went wrong"}
+	}
+
 	specs := []struct {
 		ctx    *execContext
 		in     interface{}
@@ -347,15 +354,7 @@ func TestVMConvert(t *testing.T) {
 			"feedfacedeadc0de",
 			nil,
 		},
-		// vmLoad returns an error
+		// conversion to unsupported type
-		{
-			nil,
-			&unnamedEntity{op: opAdd},
-			valueTypeInteger,
-			nil,
-			&Error{message: "readArg: unsupported entity type: " + opAdd.String()},
-		},
-		// unsupported conversion
 		{
 			nil,
 			uint64(42),
@@ -363,6 +362,13 @@ func TestVMConvert(t *testing.T) {
 			nil,
 			errConversionFailed,
 		},
+		{
+			&execContext{vm: vm},
+			&unnamedEntity{op: 0}, // uses our patched jumpTable[0] that always errors
+			valueTypeString,
+			nil,
+			&Error{message: "vmLoad: something went wrong"},
+		},
 	}
 
 	for specIndex, spec := range specs {

src/gopheros/device/acpi/aml/vm_jumptable.go

@@ -9,6 +9,21 @@ func (vm *VM) populateJumpTable() {
 	for i := 0; i < len(vm.jumpTable); i++ {
 		vm.jumpTable[i] = opExecNotImplemented
 	}
+
+	// Control-flow opcodes
+	vm.jumpTable[opReturn] = vmOpReturn
+
+	// ALU opcodes
+	vm.jumpTable[opAdd] = vmOpAdd
+	vm.jumpTable[opSubtract] = vmOpSubtract
+	vm.jumpTable[opIncrement] = vmOpIncrement
+	vm.jumpTable[opDecrement] = vmOpDecrement
+	vm.jumpTable[opMultiply] = vmOpMultiply
+	vm.jumpTable[opDivide] = vmOpDivide
+	vm.jumpTable[opMod] = vmOpMod
+
+	// Store-related opcodes
+	vm.jumpTable[opStore] = vmOpStore
 }
 
 // opExecNotImplemented is a placeholder handler that returns a non-implemented

src/gopheros/device/acpi/aml/vm_load_store.go

@@ -19,7 +19,15 @@ func vmLoad(ctx *execContext, arg interface{}) (interface{}, *Error) {
 			case opIsMethodArg(op):
 				arg = ctx.methodArg[op-opArg0]
 			default:
-				return nil, &Error{message: "readArg: unsupported entity type: " + op.String()}
+				// Val may be a nested opcode (e.g Add(Add(1,1), 2))
+				// In this case, try evaluating the opcode and replace arg with the
+				// output value that gets stored stored into ctx.retVal
+				if err := ctx.vm.jumpTable[typ.getOpcode()](ctx, typ); err != nil {
+					err.message = "vmLoad: " + err.message
+					return nil, err
+				}
+
+				arg = ctx.retVal
 			}
 		case bool:
 			// Convert boolean results to ints so they can be used

src/gopheros/device/acpi/aml/vm_load_store_test.go

@@ -6,6 +6,18 @@ import (
 )
 
 func TestVMLoad(t *testing.T) {
+	vm := NewVM(nil, nil)
+	vm.populateJumpTable()
+
+	vm.jumpTable[0] = func(_ *execContext, ent Entity) *Error {
+		return &Error{message: "something went wrong"}
+	}
+
+	vm.jumpTable[1] = func(ctx *execContext, ent Entity) *Error {
+		ctx.retVal = uint64(123)
+		return nil
+	}
+
 	// Use a pointer to ensure that when we dereference an objRef we get
 	// back the same pointer
 	uniqueVal := &execContext{}
@@ -74,12 +86,19 @@ func TestVMLoad(t *testing.T) {
 			aRef,
 			nil,
 		},
-		// Unsupported reads
+		// nested opcode which returns an error
 		{
+			&execContext{vm: vm},
+			&unnamedEntity{op: 0}, // uses our patched jumpTable[0] that always errors
 			nil,
-			&unnamedEntity{op: opBuffer},
+			&Error{message: "vmLoad: something went wrong"},
+		},
+		// nested opcode which does not return an error
+		{
+			&execContext{vm: vm},
+			&unnamedEntity{op: 1}, // uses our patched jumpTable[1]
+			uint64(123),
 			nil,
-			&Error{message: "readArg: unsupported entity type: Buffer"},
 		},
 	}
 

src/gopheros/device/acpi/aml/vm_op_alu.go

@@ -0,0 +1,136 @@
+package aml
+
+// Args: left, right, store?
+// Returns: left + right
+func vmOpAdd(ctx *execContext, ent Entity) *Error {
+	var (
+		left, right uint64
+		err         *Error
+	)
+
+	if left, right, err = vmToIntArgs2(ctx, ent, 0, 1); err != nil {
+		return err
+	}
+
+	ctx.retVal = left + right
+	return vmCondStore(ctx, ctx.retVal, ent, 2)
+}
+
+// Args: left, right, store?
+// Returns: left - right
+func vmOpSubtract(ctx *execContext, ent Entity) *Error {
+	var (
+		left, right uint64
+		err         *Error
+	)
+
+	if left, right, err = vmToIntArgs2(ctx, ent, 0, 1); err != nil {
+		return err
+	}
+
+	ctx.retVal = left - right
+	return vmCondStore(ctx, ctx.retVal, ent, 2)
+}
+
+// Args: left, store?
+// Returns: left + 1
+// Stores: left <= left + 1
+func vmOpIncrement(ctx *execContext, ent Entity) *Error {
+	var (
+		left uint64
+		err  *Error
+	)
+
+	if left, err = vmToIntArg(ctx, ent, 0); err != nil {
+		return err
+	}
+
+	// The result is stored back into the left operand
+	ctx.retVal = left + 1
+	if err := vmStore(ctx, ctx.retVal, ent.getArgs()[0]); err != nil {
+		return err
+	}
+	return vmCondStore(ctx, ctx.retVal, ent, 1)
+}
+
+// Args: left, store?
+// Returns: left - 1
+// Stores: left <= left - 1
+func vmOpDecrement(ctx *execContext, ent Entity) *Error {
+	var (
+		left uint64
+		err  *Error
+	)
+
+	if left, err = vmToIntArg(ctx, ent, 0); err != nil {
+		return err
+	}
+
+	// The result is stored back into the left operand
+	ctx.retVal = left - 1
+	if err := vmStore(ctx, ctx.retVal, ent.getArgs()[0]); err != nil {
+		return err
+	}
+	return vmCondStore(ctx, ctx.retVal, ent, 1)
+}
+
+// Args: left, right, store?
+// Returns: left * right
+func vmOpMultiply(ctx *execContext, ent Entity) *Error {
+	var (
+		left, right uint64
+		err         *Error
+	)
+
+	if left, right, err = vmToIntArgs2(ctx, ent, 0, 1); err != nil {
+		return err
+	}
+
+	ctx.retVal = left * right
+	return vmCondStore(ctx, ctx.retVal, ent, 2)
+}
+
+// Args: left, right, remainder_store?, quotient_store?
+// Returns: left / right; errDivideByZero if right == 0
+func vmOpDivide(ctx *execContext, ent Entity) *Error {
+	var (
+		left, right uint64
+		err         *Error
+	)
+
+	if left, right, err = vmToIntArgs2(ctx, ent, 0, 1); err != nil {
+		return err
+	}
+
+	if right == 0 {
+		return errDivideByZero
+	}
+
+	ctx.retVal = left / right
+	if err = vmCondStore(ctx, ctx.retVal, ent, 3); err != nil {
+		return err
+	}
+
+	// opDivide can also spefify a target for storing the remainder
+	return vmCondStore(ctx, left%right, ent, 2)
+}
+
+// Args: left, right, remainder_store?
+// Returns: left % right; errDivideByZero if right == 0
+func vmOpMod(ctx *execContext, ent Entity) *Error {
+	var (
+		left, right uint64
+		err         *Error
+	)
+
+	if left, right, err = vmToIntArgs2(ctx, ent, 0, 1); err != nil {
+		return err
+	}
+
+	if right == 0 {
+		return errDivideByZero
+	}
+
+	ctx.retVal = left % right
+	return vmCondStore(ctx, ctx.retVal, ent, 2)
+}

src/gopheros/device/acpi/aml/vm_op_alu_test.go

@@ -0,0 +1,128 @@
+package aml
+
+import (
+	"os"
+	"reflect"
+	"testing"
+)
+
+func TestArithmeticExpressions(t *testing.T) {
+	specs := []struct {
+		method string
+		input  interface{}
+		exp    uint64
+	}{
+		{`\AR00`, uint64(10), uint64(15)},
+		{`\ARI0`, uint64(10), uint64(15)},
+		{`\AR01`, uint64(6), uint64(1)},
+		{`\ARI1`, uint64(6), uint64(1)},
+		{`\AR02`, uint64(3), uint64(24)},
+		{`\ARI2`, uint64(3), uint64(24)},
+		{`\AR03`, uint64(42), uint64(41)},
+		{`\ARI3`, uint64(42), uint64(41)},
+		{`\AR04`, uint64(42), uint64(43)},
+		{`\ARI4`, uint64(42), uint64(43)},
+		{`\AR05`, uint64(100), uint64(0)},
+		{`\ARI5`, uint64(100), uint64(0)},
+		{`\AR06`, uint64(100), uint64(10)},
+		{`\ARI6`, uint64(100), uint64(10)},
+		{`\AR06`, uint64(101), uint64(11)},
+		{`\ARI6`, uint64(101), uint64(10)},
+	}
+
+	resolver := &mockResolver{
+		tableFiles: []string{"vm-testsuite-DSDT.aml"},
+	}
+
+	vm := NewVM(os.Stderr, resolver)
+	if err := vm.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	for specIndex, spec := range specs {
+		m := vm.Lookup(spec.method)
+		if m == nil {
+			t.Errorf("error looking up method: %q", spec.method)
+			continue
+		}
+
+		method := m.(*Method)
+
+		ctx := &execContext{
+			methodArg: [maxMethodArgs]interface{}{spec.input},
+			vm:        vm,
+		}
+
+		if err := vm.execBlock(ctx, method); err != nil {
+			t.Errorf("[spec %02d] %s: invocation failed: %v\n", specIndex, spec.method, err)
+			continue
+		}
+
+		if !reflect.DeepEqual(ctx.retVal, spec.exp) {
+			t.Errorf("[spec %02d] %s: expected %d; got %v\n", specIndex, spec.method, spec.exp, ctx.retVal)
+		}
+	}
+}
+
+func TestArithmeticExpressionErrors(t *testing.T) {
+	t.Run("arg handling errors", func(t *testing.T) {
+		specs := []opHandler{
+			vmOpAdd,
+			vmOpSubtract,
+			vmOpIncrement,
+			vmOpDecrement,
+			vmOpMultiply,
+			vmOpDivide,
+			vmOpMod,
+		}
+
+		for specIndex, handler := range specs {
+			if err := handler(nil, new(unnamedEntity)); err == nil {
+				t.Errorf("[spec %d] expected opHandler to return an error", specIndex)
+			}
+		}
+	})
+
+	t.Run("division by zero errors", func(t *testing.T) {
+		specs := []opHandler{
+			vmOpDivide,
+			vmOpMod,
+		}
+
+		ent := &unnamedEntity{
+			args: []interface{}{
+				&constEntity{val: uint64(1)},
+				&constEntity{val: uint64(0)},
+			},
+		}
+		for specIndex, handler := range specs {
+			if err := handler(nil, ent); err != errDivideByZero {
+				t.Errorf("[spec %d] expected opHandler to return errDivideByZero; got %v", specIndex, err)
+			}
+		}
+	})
+
+	t.Run("secondary value store errors", func(t *testing.T) {
+		specs := []opHandler{
+			vmOpIncrement,
+			vmOpDecrement,
+			vmOpDivide,
+			vmOpMod,
+		}
+
+		ctx := new(execContext)
+		ent := &unnamedEntity{
+			args: []interface{}{
+				uint64(64),
+				&constEntity{val: uint64(4)},
+				"foo", // error: store target must be an AML entity
+				"bar", // error: store target must be an AML entity
+			},
+		}
+		for specIndex, handler := range specs {
+			if err := handler(ctx, ent); err != errInvalidStoreDestination {
+				t.Errorf("[spec %d] expected opHandler to return errInvalidStoreDestination; got %v", specIndex, err)
+			}
+		}
+	})
+}

src/gopheros/device/acpi/aml/vm_op_flow.go

@@ -0,0 +1,16 @@
+package aml
+
+// Args: val
+// Set val as the return value in ctx and change the ctrlFlow
+// type to ctrlFlowTypeFnReturn.
+func vmOpReturn(ctx *execContext, ent Entity) *Error {
+	args := ent.getArgs()
+	if len(args) != 1 {
+		return errArgIndexOutOfBounds
+	}
+
+	var err *Error
+	ctx.ctrlFlow = ctrlFlowTypeFnReturn
+	ctx.retVal, err = vmLoad(ctx, args[0])
+	return err
+}

src/gopheros/device/acpi/aml/vm_op_flow_test.go

@@ -0,0 +1,12 @@
+package aml
+
+import "testing"
+
+func TestFlowExpressionErrors(t *testing.T) {
+	t.Run("opReturn errors", func(t *testing.T) {
+		// opReturn expects an argument to evaluate as the return value
+		if err := vmOpReturn(nil, new(unnamedEntity)); err != errArgIndexOutOfBounds {
+			t.Errorf("expected to get errArgIndexOutOfBounds; got %v", err)
+		}
+	})
+}

src/gopheros/device/acpi/aml/vm_op_store.go

@@ -0,0 +1,17 @@
+package aml
+
+// Args: src dst
+// Store src into dst applying any required conversion.
+func vmOpStore(ctx *execContext, ent Entity) *Error {
+	args := ent.getArgs()
+	if len(args) != 2 {
+		return errArgIndexOutOfBounds
+	}
+
+	val, err := vmLoad(ctx, args[0])
+	if err != nil {
+		return err
+	}
+
+	return vmStore(ctx, val, args[1])
+}

src/gopheros/device/acpi/aml/vm_op_store_test.go

@@ -0,0 +1,41 @@
+package aml
+
+import "testing"
+
+func TestVMOpStoreErrors(t *testing.T) {
+	// Wrong arg count
+	if err := vmOpStore(nil, new(unnamedEntity)); err != errArgIndexOutOfBounds {
+		t.Errorf("expected to get errArgIndexOutOfBounds; got %v", err)
+	}
+
+	// Error loading the value to be stored
+	expErr := &Error{message: "something went wrong"}
+
+	vm := NewVM(nil, nil)
+	vm.populateJumpTable()
+	vm.jumpTable[0] = func(_ *execContext, ent Entity) *Error {
+		return expErr
+	}
+
+	ent := &unnamedEntity{
+		args: []interface{}{
+			// vmLoad will try to eval jumptable[0] which we monkey-patched to return an error
+			&unnamedEntity{op: 0},
+			uint64(128),
+		},
+	}
+
+	if err := vmOpStore(&execContext{vm: vm}, ent); err != expErr {
+		t.Errorf("expected to get error %q; got %v", expErr.Error(), err)
+	}
+
+	// Error storing the value
+	ent.args = []interface{}{
+		uint64(128),
+		uint64(0xf00), // storing to a non-AML entity is an error
+	}
+
+	if err := vmOpStore(nil, ent); err != errInvalidStoreDestination {
+		t.Errorf("expected to get errInvalidStoreDestination; got %v", err)
+	}
+}

src/gopheros/device/acpi/table/tabletest/vm-testsuite-DSDT.dsl

@@ -0,0 +1,84 @@
+DefinitionBlock ("vm-testsuite-DSDT.aml", "DSDT", 2, "GOPHER", "GOPHEROS", 0x00000002)
+{
+  // Arithmetic ops
+  Method (AR00, 1, NotSerialized)
+  {
+    Add(Arg0, 5, Local0)
+    Return(Local0)
+  }
+
+  Method (ARI0, 1, NotSerialized)
+  {
+    Return(Arg0 + 5)
+  }
+
+  Method (AR01, 1, NotSerialized)
+  {
+    Subtract(Arg0, 5, Local0)
+    Return(Local0)
+  }
+
+  Method (ARI1, 1, NotSerialized)
+  {
+    Return(Arg0 - 5)
+  }
+
+  Method (AR02, 1, NotSerialized)
+  {
+    Multiply(Arg0, 8, Local0)
+    Return(Local0)
+  }
+
+  Method (ARI2, 1, NotSerialized)
+  {
+    Return(Arg0*8)
+  }
+
+  Method (AR03, 1, NotSerialized)
+  {
+    Local1 = Arg0
+    Local1--
+    Return(Local1)
+  }
+
+  Method (ARI3, 1, NotSerialized)
+  {
+    Return(Arg0--)
+  }
+
+  Method (AR04, 1, NotSerialized)
+  {
+    Local2 = Arg0
+    Local2++
+    Return(Local2)
+  }
+
+  Method (ARI4, 1, NotSerialized)
+  {
+    Return(Arg0++)
+  }
+
+  Method (AR05, 1, NotSerialized)
+  {
+    Mod(Arg0, 10, Local0)
+    Return(Local0)
+  }
+
+  Method (ARI5, 1, NotSerialized)
+  {
+    Return(Arg0 % 10)
+  }
+
+  Method (AR06, 1, NotSerialized)
+  {
+    // Local0: remainder
+    // Local1: quotient
+    Divide(Arg0, 10, Local0, Local1)
+    Return(Local0 + Local1)
+  }
+
+  Method (ARI6, 1, NotSerialized)
+  {
+    Return(Arg0 / 10)
+  }
+}