@@ -126,7 +126,7 @@ func (is *imageSource) ResolveImageConfig(ctx context.Context, ref string) (dige

 		dt   []byte

 	}

 	res, err := is.g.Do(ctx, ref, func(ctx context.Context) (interface{}, error) {

-		dgst, dt, err := imageutil.Config(ctx, ref, is.getResolver(ctx), is.ContentStore, "")

+		dgst, dt, err := imageutil.Config(ctx, ref, is.getResolver(ctx), is.ContentStore, nil)

 		if err != nil {

 			return nil, err

 		}

@@ -10,6 +10,7 @@ import (

 	"time"

 	"github.com/containerd/containerd/content"

+	"github.com/containerd/containerd/platforms"

 	"github.com/containerd/containerd/rootfs"

 	"github.com/docker/docker/distribution"

 	distmetadata "github.com/docker/docker/distribution/metadata"

@@ -122,6 +123,12 @@ func (w *Worker) Labels() map[string]string {

 	return w.Opt.Labels

 }

+// Platforms returns one or more platforms supported by the image.

+func (w *Worker) Platforms() []ocispec.Platform {

+	// does not handle lcow

+	return []ocispec.Platform{platforms.DefaultSpec()}

+}

+

 // LoadRef loads a reference by ID

 func (w *Worker) LoadRef(id string) (cache.ImmutableRef, error) {

 	return w.CacheManager.Get(context.TODO(), id)

@@ -129,26 +136,27 @@ func (w *Worker) LoadRef(id string) (cache.ImmutableRef, error) {

 // ResolveOp converts a LLB vertex into a LLB operation

 func (w *Worker) ResolveOp(v solver.Vertex, s frontend.FrontendLLBBridge) (solver.Op, error) {

-	switch op := v.Sys().(type) {

-	case *pb.Op_Source:

-		return ops.NewSourceOp(v, op, w.SourceManager, w)

-	case *pb.Op_Exec:

-		return ops.NewExecOp(v, op, w.CacheManager, w.MetadataStore, w.Executor, w)

-	case *pb.Op_Build:

-		return ops.NewBuildOp(v, op, s, w)

-	default:

-		return nil, errors.Errorf("could not resolve %v", v)

+	if baseOp, ok := v.Sys().(*pb.Op); ok {

+		switch op := baseOp.Op.(type) {

+		case *pb.Op_Source:

+			return ops.NewSourceOp(v, op, baseOp.Platform, w.SourceManager, w)

+		case *pb.Op_Exec:

+			return ops.NewExecOp(v, op, w.CacheManager, w.MetadataStore, w.Executor, w)

+		case *pb.Op_Build:

+			return ops.NewBuildOp(v, op, s, w)

+		}

 	}

+	return nil, errors.Errorf("could not resolve %v", v)

 }

 // ResolveImageConfig returns image config for an image

-func (w *Worker) ResolveImageConfig(ctx context.Context, ref string) (digest.Digest, []byte, error) {

+func (w *Worker) ResolveImageConfig(ctx context.Context, ref string, platform *ocispec.Platform) (digest.Digest, []byte, error) {

 	// ImageSource is typically source/containerimage

 	resolveImageConfig, ok := w.ImageSource.(resolveImageConfig)

 	if !ok {

 		return "", nil, errors.Errorf("worker %q does not implement ResolveImageConfig", w.ID())

 	}

-	return resolveImageConfig.ResolveImageConfig(ctx, ref)

+	return resolveImageConfig.ResolveImageConfig(ctx, ref, platform)

 }

 // Exec executes a process directly on a worker

@@ -319,5 +327,5 @@ func oneOffProgress(ctx context.Context, id string) func(err error) error {

 }

 type resolveImageConfig interface {

-	ResolveImageConfig(ctx context.Context, ref string) (digest.Digest, []byte, error)

+	ResolveImageConfig(ctx context.Context, ref string, platform *ocispec.Platform) (digest.Digest, []byte, error)

 }

@@ -152,12 +152,23 @@ func (d *dispatchRequest) getImageMount(imageRefOrID string) (*imageMount, error

 //

 func initializeStage(d dispatchRequest, cmd *instructions.Stage) error {

 	d.builder.imageProber.Reset()

-	//TODO(@arm64b): Leave the sanity check of the spec platform to the containerd code

-	if err := platforms.ValidatePlatform(&cmd.Platform); err != nil {

-		return err

-	}

-	image, err := d.getFromImage(d.shlex, cmd.BaseName, cmd.Platform.OS)

+	// TODO: pass *platform instead, allow autodetect

+	platform := platforms.DefaultSpec()

+	if v := cmd.Platform; v != "" {

+		// TODO:

+		// v, err := shlex.ProcessWord(v, toEnvList(metaArgs, nil))

+		// if err != nil {

+		// 	return nil, nil, errors.Wrapf(err, "failed to process arguments for platform %s", v)

+		// }

+

+		p, err := platforms.Parse(v)

+		if err != nil {

+			return errors.Wrapf(err, "failed to parse platform %s", v)

+		}

+		platform = p

+	}

+	image, err := d.getFromImage(d.shlex, cmd.BaseName, platform.OS)

 	if err != nil {

 		return err

 	}

@@ -2,6 +2,7 @@ package system // import "github.com/docker/docker/pkg/system"

 import (

 	"runtime"

+	"strings"

 )

 // IsOSSupported determines if an operating system is supported by the host