features: consider ENOTSUPP in v2 and v4 ISA probes as conclusive

With the addition of the v4 ISA probe, we noticed an ENOTSUPP being returned by
BPF_PROG_LOAD on aarch64. Typically, this is an error code internal to the
verifier/JIT, but on aarch64 it seems to bubble up.

Since we cannot currently test older arm kernels, apply this logic to the older
ISA probes as well.

Signed-off-by: Timo Beckers <timo@isovalent.com>

features/misc.go

@@ -1,9 +1,12 @@
 package features
 
 import (
+	"errors"
+
 	"github.com/cilium/ebpf"
 	"github.com/cilium/ebpf/asm"
 	"github.com/cilium/ebpf/internal"
+	"github.com/cilium/ebpf/internal/sys"
 )
 
 // HaveLargeInstructions probes the running kernel if more than 4096 instructions
@@ -62,7 +65,7 @@ func HaveV2ISA() error {
 }
 
 var haveV2ISA = internal.NewFeatureTest("v2 ISA", func() error {
-	return probeProgram(&ebpf.ProgramSpec{
+	err := probeProgram(&ebpf.ProgramSpec{
 		Type: ebpf.SocketFilter,
 		Instructions: asm.Instructions{
 			asm.Mov.Imm(asm.R0, 0),
@@ -71,6 +74,11 @@ var haveV2ISA = internal.NewFeatureTest("v2 ISA", func() error {
 			asm.Return().WithSymbol("exit"),
 		},
 	})
+	// This sometimes bubbles up from the JIT on aarch64.
+	if errors.Is(err, sys.ENOTSUPP) {
+		return ebpf.ErrNotSupported
+	}
+	return err
 }, "4.14")
 
 // HaveV3ISA probes the running kernel if instructions of the v3 ISA are supported.
@@ -83,7 +91,7 @@ func HaveV3ISA() error {
 }
 
 var haveV3ISA = internal.NewFeatureTest("v3 ISA", func() error {
-	return probeProgram(&ebpf.ProgramSpec{
+	err := probeProgram(&ebpf.ProgramSpec{
 		Type: ebpf.SocketFilter,
 		Instructions: asm.Instructions{
 			asm.Mov.Imm(asm.R0, 0),
@@ -92,6 +100,11 @@ var haveV3ISA = internal.NewFeatureTest("v3 ISA", func() error {
 			asm.Return().WithSymbol("exit"),
 		},
 	})
+	// This sometimes bubbles up from the JIT on aarch64.
+	if errors.Is(err, sys.ENOTSUPP) {
+		return ebpf.ErrNotSupported
+	}
+	return err
 }, "5.1")
 
 // HaveV4ISA probes the running kernel if instructions of the v4 ISA are supported.