@@ -14,6 +14,7 @@ import (

 	"strings"

 	"sync"

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

 	"github.com/docker/docker/api/server/httputils"

 	"github.com/docker/docker/api/types"

 	"github.com/docker/docker/api/types/backend"

@@ -23,7 +24,6 @@ import (

 	"github.com/docker/docker/pkg/ioutils"

 	"github.com/docker/docker/pkg/progress"

 	"github.com/docker/docker/pkg/streamformatter"

-	"github.com/docker/docker/pkg/system"

 	"github.com/docker/go-units"

 	"github.com/pkg/errors"

 	"github.com/sirupsen/logrus"

@@ -72,11 +72,13 @@ func newImageBuildOptions(ctx context.Context, r *http.Request) (*types.ImageBui

 	options.RemoteContext = r.FormValue("remote")

 	if versions.GreaterThanOrEqualTo(version, "1.32") {

 		apiPlatform := r.FormValue("platform")

-		p := system.ParsePlatform(apiPlatform)

-		if err := system.ValidatePlatform(p); err != nil {

-			return nil, errdefs.InvalidParameter(errors.Errorf("invalid platform: %s", err))

+		if len(strings.TrimSpace(apiPlatform)) != 0 {

+			sp, err := platforms.Parse(apiPlatform)

+			if err != nil {

+				return nil, err

+			}

+			options.Platform = sp

 		}

-		options.Platform = p.OS

 	}

 	if r.Form.Get("shmsize") != "" {

@@ -4,11 +4,11 @@ import (

 	"context"

 	"encoding/base64"

 	"encoding/json"

-	"fmt"

 	"net/http"

 	"strconv"

 	"strings"

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

 	"github.com/docker/docker/api/server/httputils"

 	"github.com/docker/docker/api/types"

 	"github.com/docker/docker/api/types/filters"

@@ -16,7 +16,6 @@ import (

 	"github.com/docker/docker/errdefs"

 	"github.com/docker/docker/pkg/ioutils"

 	"github.com/docker/docker/pkg/streamformatter"

-	"github.com/docker/docker/pkg/system"

 	"github.com/docker/docker/registry"

 	specs "github.com/opencontainers/image-spec/specs-go/v1"

 	"github.com/pkg/errors"

@@ -45,9 +44,12 @@ func (s *imageRouter) postImagesCreate(ctx context.Context, w http.ResponseWrite

 	version := httputils.VersionFromContext(ctx)

 	if versions.GreaterThanOrEqualTo(version, "1.32") {

 		apiPlatform := r.FormValue("platform")

-		platform = system.ParsePlatform(apiPlatform)

-		if err = system.ValidatePlatform(platform); err != nil {

-			err = fmt.Errorf("invalid platform: %s", err)

+		if len(strings.TrimSpace(apiPlatform)) != 0 {

+			sp, err := platforms.Parse(apiPlatform)

+			if err != nil {

+				return err

+			}

+			platform = &sp

 		}

 	}

@@ -8,6 +8,7 @@ import (

 	"github.com/docker/docker/api/types/container"

 	"github.com/docker/docker/api/types/filters"

 	"github.com/docker/go-units"

+	specs "github.com/opencontainers/image-spec/specs-go/v1"

 )

 // CheckpointCreateOptions holds parameters to create a checkpoint from a container

@@ -180,7 +181,7 @@ type ImageBuildOptions struct {

 	ExtraHosts  []string // List of extra hosts

 	Target      string

 	SessionID   string

-	Platform    string

+	Platform    specs.Platform

 	// Version specifies the version of the unerlying builder to use

 	Version BuilderVersion

 	// BuildID is an optional identifier that can be passed together with the

@@ -104,13 +104,6 @@ func (bm *BuildManager) Build(ctx context.Context, config backend.BuildConfig) (

 		source = src

 	}

-	os := ""

-	apiPlatform := system.ParsePlatform(config.Options.Platform)

-	if apiPlatform.OS != "" {

-		os = apiPlatform.OS

-	}

-	config.Options.Platform = os

-

 	builderOptions := builderOptions{

 		Options:        config.Options,

 		ProgressWriter: config.ProgressWriter,

@@ -24,6 +24,7 @@ import (

 	"github.com/docker/docker/pkg/streamformatter"

 	"github.com/docker/docker/pkg/system"

 	"github.com/docker/docker/pkg/urlutil"

+	specs "github.com/opencontainers/image-spec/specs-go/v1"

 	"github.com/pkg/errors"

 )

@@ -72,7 +73,7 @@ type copier struct {

 	source      builder.Source

 	pathCache   pathCache

 	download    sourceDownloader

-	platform    string

+	platform    specs.Platform

 	// for cleanup. TODO: having copier.cleanup() is error prone and hard to

 	// follow. Code calling performCopy should manage the lifecycle of its params.

 	// Copier should take override source as input, not imageMount.

@@ -95,8 +96,8 @@ func (o *copier) createCopyInstruction(args []string, cmdName string) (copyInstr

 	last := len(args) - 1

 	// Work in platform-specific filepath semantics

-	inst.dest = fromSlash(args[last], o.platform)

-	separator := string(separator(o.platform))

+	inst.dest = fromSlash(args[last], o.platform.OS)

+	separator := string(separator(o.platform.OS))

 	infos, err := o.getCopyInfosForSourcePaths(args[0:last], inst.dest)

 	if err != nil {

 		return inst, errors.Wrapf(err, "%s failed", cmdName)

@@ -14,6 +14,7 @@ import (

 	"sort"

 	"strings"

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

 	"github.com/docker/docker/api"

 	"github.com/docker/docker/api/types/container"

 	"github.com/docker/docker/api/types/strslice"

@@ -151,9 +152,11 @@ func (d *dispatchRequest) getImageMount(imageRefOrID string) (*imageMount, error

 //

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

 	d.builder.imageProber.Reset()

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

+	//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)

 	if err != nil {

 		return err

@@ -223,10 +226,10 @@ func (d *dispatchRequest) getOsFromFlagsAndStage(stageOS string) string {

 	switch {

 	case stageOS != "":

 		return stageOS

-	case d.builder.options.Platform != "":

+	case d.builder.options.Platform.OS != "":

 		// Note this is API "platform", but by this point, as the daemon is not

 		// multi-arch aware yet, it is guaranteed to only hold the OS part here.

-		return d.builder.options.Platform

+		return d.builder.options.Platform.OS

 	default:

 		return "" // Auto-select

 	}

@@ -456,7 +456,7 @@ func hostConfigFromOptions(options *types.ImageBuildOptions) *container.HostConf

 	// is too small for builder scenarios where many users are

 	// using RUN statements to install large amounts of data.

 	// Use 127GB as that's the default size of a VHD in Hyper-V.

-	if runtime.GOOS == "windows" && options.Platform == "windows" {

+	if runtime.GOOS == "windows" && options.Platform.OS == "windows" {

 		hc.StorageOpt = make(map[string]string)

 		hc.StorageOpt["size"] = "127GB"

 	}

@@ -422,8 +422,6 @@ func checkCompatibleOS(imageOS string) error {

 		return fmt.Errorf("cannot load %s image on %s", imageOS, runtime.GOOS)

 	}

 	// Finally, check the image OS is supported for the platform.

-	if err := system.ValidatePlatform(system.ParsePlatform(imageOS)); err != nil {

-		return fmt.Errorf("cannot load %s image on %s: %s", imageOS, runtime.GOOS, err)

-	}

+	// TODO(@arm64b): Leave this sanity check to the containerd code in the future

 	return nil

 }

@@ -1,62 +1,9 @@

 package system // import "github.com/docker/docker/pkg/system"

 import (

-	"fmt"

 	"runtime"

-	"strings"

-

-	specs "github.com/opencontainers/image-spec/specs-go/v1"

 )

-// ValidatePlatform determines if a platform structure is valid.

-// TODO This is a temporary function - can be replaced by parsing from

-// https://github.com/containerd/containerd/pull/1403/files at a later date.

-// @jhowardmsft

-func ValidatePlatform(platform *specs.Platform) error {

-	platform.Architecture = strings.ToLower(platform.Architecture)

-	platform.OS = strings.ToLower(platform.OS)

-	// Based on https://github.com/moby/moby/pull/34642#issuecomment-330375350, do

-	// not support anything except operating system.

-	if platform.Architecture != "" {

-		return fmt.Errorf("invalid platform architecture %q", platform.Architecture)

-	}

-	if platform.OS != "" {

-		if !(platform.OS == runtime.GOOS || (LCOWSupported() && platform.OS == "linux")) {

-			return fmt.Errorf("invalid platform os %q", platform.OS)

-		}

-	}

-	if len(platform.OSFeatures) != 0 {

-		return fmt.Errorf("invalid platform osfeatures %q", platform.OSFeatures)

-	}

-	if platform.OSVersion != "" {

-		return fmt.Errorf("invalid platform osversion %q", platform.OSVersion)

-	}

-	if platform.Variant != "" {

-		return fmt.Errorf("invalid platform variant %q", platform.Variant)

-	}

-	return nil

-}

-

-// ParsePlatform parses a platform string in the format os[/arch[/variant]

-// into an OCI image-spec platform structure.

-// TODO This is a temporary function - can be replaced by parsing from

-// https://github.com/containerd/containerd/pull/1403/files at a later date.

-// @jhowardmsft

-func ParsePlatform(in string) *specs.Platform {

-	p := &specs.Platform{}

-	elements := strings.SplitN(strings.ToLower(in), "/", 3)

-	if len(elements) == 3 {

-		p.Variant = elements[2]

-	}

-	if len(elements) >= 2 {

-		p.Architecture = elements[1]

-	}

-	if len(elements) >= 1 {

-		p.OS = elements[0]

-	}

-	return p

-}

-

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

 func IsOSSupported(os string) bool {

 	if strings.EqualFold(runtime.GOOS, os) {