acpi: instanciate AML interpreter when the ACPI driver is initialized

src/gopheros/device/acpi/acpi.go

@@ -2,6 +2,7 @@ package acpi
 
 import (
 	"gopheros/device"
+	"gopheros/device/acpi/aml"
 	"gopheros/device/acpi/table"
 	"gopheros/kernel"
 	"gopheros/kernel/kfmt"
@@ -45,17 +46,33 @@ type acpiDriver struct {
 	// by the table name. All tables included in this map are mapped into
 	// memory.
 	tableMap map[string]*table.SDTHeader
+
+	// The AML interpreter used by the ACPI driver to execute various
+	// ACPI-related methods.
+	amlVM *aml.VM
 }
 
 // DriverInit initializes this driver.
 func (drv *acpiDriver) DriverInit(w io.Writer) *kernel.Error {
-	if err := drv.enumerateTables(w); err != nil {
+	var err *kernel.Error
+
+	if err = drv.enumerateTables(w); err != nil {
 		return err
 	}
-
 	drv.printTableInfo(w)
 
-	return nil
+	// Now that we have enumerated the available ACPI tables we can
+	// initialize the AML interpreter passing the driver instance as
+	// a table.Resolver.
+	drv.amlVM = aml.NewVM(w, drv)
+	if vmErr := drv.amlVM.Init(); vmErr != nil {
+		return &kernel.Error{
+			Module:  "acpi",
+			Message: vmErr.Error(),
+		}
+	}
+
+	return err
 }
 
 // DriverName returns the name of this driver.
@@ -68,6 +85,11 @@ func (*acpiDriver) DriverVersion() (uint16, uint16, uint16) {
 	return 0, 0, 1
 }
 
+// LookupTable implements the table.Resolver interface.
+func (drv *acpiDriver) LookupTable(name string) *table.SDTHeader {
+	return drv.tableMap[name]
+}
+
 func (drv *acpiDriver) printTableInfo(w io.Writer) {
 	for name, header := range drv.tableMap {
 		kfmt.Fprintf(w, "%s at 0x%16x %6x (%6s %8s)\n",
@@ -84,6 +106,10 @@ func (drv *acpiDriver) printTableInfo(w io.Writer) {
 // the table list defined by the RSDP, this method will also peek into the
 // FADT (if found) looking for the address of DSDT.
 func (drv *acpiDriver) enumerateTables(w io.Writer) *kernel.Error {
+	if len(drv.tableMap) != 0 {
+		return nil
+	}
+
 	header, sizeofHeader, err := mapACPITable(drv.rsdtAddr)
 	if err != nil {
 		return err

src/gopheros/device/acpi/acpi_test.go

@@ -9,6 +9,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"reflect"
 	"runtime"
 	"testing"
 	"unsafe"
@@ -237,6 +238,33 @@ func TestDriverInit(t *testing.T) {
 		}
 	})
 
+	t.Run("AML interpreter init error", func(t *testing.T) {
+		rsdtAddr, _ := genTestRDST(t, acpiRev2Plus)
+		identityMapFn = func(frame pmm.Frame, _ mem.Size, _ vmm.PageTableEntryFlag) (vmm.Page, *kernel.Error) {
+			return vmm.Page(frame), nil
+		}
+
+		drv := &acpiDriver{
+			rsdtAddr: rsdtAddr,
+			useXSDT:  true,
+		}
+
+		// Patch the DSDT with an incomplete extOpPrefix opcode; this
+		// will trigger an error when trying to parse its AML contents
+		drv.enumerateTables(ioutil.Discard)
+		header := drv.LookupTable("DSDT")
+		rawData := *(*[]byte)(unsafe.Pointer(&reflect.SliceHeader{
+			Len:  int(header.Length),
+			Cap:  int(header.Length),
+			Data: uintptr(unsafe.Pointer(header)) + unsafe.Sizeof(table.SDTHeader{}),
+		}))
+		rawData[0] = 0x1b // extOpPrefix
+
+		expErr := "acpi_aml_parser: could not parse AML bytecode"
+		if err := drv.DriverInit(os.Stderr); err == nil || err.Error() != expErr {
+			t.Fatalf("expected to get an AML parse error; got %v", err)
+		}
+	})
 }
 
 func TestEnumerateTables(t *testing.T) {

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

@@ -90,7 +90,6 @@ func (vm *VM) Init() *Error {
 		if header == nil {
 			continue
 		}
-
 		if err := vm.tableParser.ParseAML(uint8(tableHandle+1), tableName, header); err != nil {
 			return &Error{message: err.Module + ": " + err.Error()}
 		}