Replace internal.NativeEndian with stdlib (1/2)

asm/instruction.go

@@ -11,6 +11,7 @@ import (
 	"sort"
 	"strings"
 
+	"github.com/cilium/ebpf/internal"
 	"github.com/cilium/ebpf/internal/sys"
 )
 
@@ -51,7 +52,7 @@ func (ins *Instruction) Unmarshal(r io.Reader, bo binary.ByteOrder) (uint64, err
 	ins.OpCode = OpCode(data[0])
 
 	regs := data[1]
-	switch bo {
+	switch internal.NormalizeByteOrder(bo) {
 	case binary.LittleEndian:
 		ins.Dst, ins.Src = Register(regs&0xF), Register(regs>>4)
 	case binary.BigEndian:
@@ -934,7 +935,7 @@ func (iter *InstructionIterator) Next() bool {
 type bpfRegisters uint8
 
 func newBPFRegisters(dst, src Register, bo binary.ByteOrder) (bpfRegisters, error) {
-	switch bo {
+	switch internal.NormalizeByteOrder(bo) {
 	case binary.LittleEndian:
 		return bpfRegisters((src << 4) | (dst & 0xF)), nil
 	case binary.BigEndian:

btf/core.go

@@ -11,6 +11,7 @@ import (
 	"strings"
 
 	"github.com/cilium/ebpf/asm"
+	"github.com/cilium/ebpf/internal"
 )
 
 // Code in this file is derived from libbpf, which is available under a BSD
@@ -205,8 +206,10 @@ func CORERelocate(relos []*CORERelocation, targets []*Spec, bo binary.ByteOrder,
 	resolveTargetTypeID := targets[0].TypeID
 
 	for _, target := range targets {
-		if bo != target.imm.byteOrder {
-			return nil, fmt.Errorf("can't relocate %s against %s", bo, target.imm.byteOrder)
+		if !internal.EqualByteOrder(bo, target.imm.byteOrder) {
+			return nil, fmt.Errorf("can't relocate %s against %s",
+				internal.NormalizeByteOrder(bo),
+				internal.NormalizeByteOrder(target.imm.byteOrder))
 		}
 	}
 
@@ -488,7 +491,7 @@ func coreCalculateFixup(relo *CORERelocation, target Type, bo binary.ByteOrder,
 
 		case reloFieldLShiftU64:
 			var target uint64
-			if bo == binary.LittleEndian {
+			if internal.EqualByteOrder(bo, binary.LittleEndian) {
 				targetSize, err := targetField.sizeBits()
 				if err != nil {
 					return zero, err

elf_reader_test.go

@@ -254,7 +254,7 @@ func TestLoadCollectionSpec(t *testing.T) {
 			t.Errorf("MapSpec mismatch (-want +got):\n%s", diff)
 		}
 
-		if have.ByteOrder != internal.NativeEndian {
+		if !internal.EqualByteOrder(have.ByteOrder, binary.NativeEndian) {
 			return
 		}
 
@@ -445,7 +445,7 @@ func TestLoadInitializedBTFMap(t *testing.T) {
 		}
 
 		t.Run("NewCollection", func(t *testing.T) {
-			if coll.ByteOrder != internal.NativeEndian {
+			if !internal.EqualByteOrder(coll.ByteOrder, binary.NativeEndian) {
 				t.Skipf("Skipping %s collection", coll.ByteOrder)
 			}
 

internal/endian.go

@@ -0,0 +1,25 @@
+package internal
+
+import (
+	"encoding/binary"
+
+	"golang.org/x/sys/cpu"
+)
+
+var NativeEndian = binary.NativeEndian
+
+func EqualByteOrder(bo1, bo2 binary.ByteOrder) bool {
+	return NormalizeByteOrder(bo1) == NormalizeByteOrder(bo2)
+}
+
+// NormalizeByteOrder replaces binary.NativeEndian with the underlying
+// byte order (BigEndian or LittleEndian).
+func NormalizeByteOrder(bo binary.ByteOrder) binary.ByteOrder {
+	if bo != binary.NativeEndian {
+		return bo
+	}
+	if cpu.IsBigEndian {
+		return binary.BigEndian
+	}
+	return binary.LittleEndian
+}

prog.go

@@ -263,8 +263,10 @@ func newProgramWithOptions(spec *ProgramSpec, opts ProgramOptions) (*Program, er
 		return nil, errors.New("can't load program of unspecified type")
 	}
 
-	if spec.ByteOrder != nil && spec.ByteOrder != internal.NativeEndian {
-		return nil, fmt.Errorf("can't load %s program on %s", spec.ByteOrder, internal.NativeEndian)
+	if spec.ByteOrder != nil && !internal.EqualByteOrder(spec.ByteOrder, binary.NativeEndian) {
+		return nil, fmt.Errorf("can't load %s program on %s",
+			internal.NormalizeByteOrder(spec.ByteOrder),
+			internal.NormalizeByteOrder(binary.NativeEndian))
 	}
 
 	// Kernels before 5.0 (6c4fc209fcf9 "bpf: remove useless version check for prog load")

prog_test.go

@@ -726,7 +726,7 @@ func TestProgramRejectIncorrectByteOrder(t *testing.T) {
 	spec := socketFilterSpec.Copy()
 
 	spec.ByteOrder = binary.BigEndian
-	if spec.ByteOrder == internal.NativeEndian {
+	if internal.EqualByteOrder(spec.ByteOrder, binary.NativeEndian) {
 		spec.ByteOrder = binary.LittleEndian
 	}