tools/syz-kconf: improve support for third-party config files

Allow and "_" instance that can list intentionally unused features.
This allows to reuse upstream config bits (e.g. debug.yml)
and avoid "unknown feature" warnings.

2 files changed, 21 insertions, 9 deletions

diff --git a/tools/syz-kconf/kconf.go b/tools/syz-kconf/kconf.go
index 06d043790..92a86e0b4 100644
--- a/tools/syz-kconf/kconf.go
+++ b/tools/syz-kconf/kconf.go
@@ -51,11 +51,11 @@ func main() {
 	if err != nil {
 		tool.Failf("failed to create repo: %v", err)
 	}
-	instances, err := parseMainSpec(*flagConfig)
+	instances, unusedFeatures, err := parseMainSpec(*flagConfig)
 	if err != nil {
 		tool.Fail(err)
 	}
-	if err := checkConfigs(instances); err != nil {
+	if err := checkConfigs(instances, unusedFeatures); err != nil {
 		tool.Fail(err)
 	}
 	// In order to speed up the process we generate instances that use the same kernel revision in parallel.
@@ -115,8 +115,11 @@ func main() {
 	}
 }
 
-func checkConfigs(instances []*Instance) error {
+func checkConfigs(instances []*Instance, unusedFeatures []string) error {
 	allFeatures := make(Features)
+	for _, feat := range unusedFeatures {
+		allFeatures[feat] = true
+	}
 	for _, inst := range instances {
 		for feat := range inst.Features {
 			allFeatures[feat] = true
@@ -239,6 +242,7 @@ func (ctx *Context) executeShell() error {
 		args := strings.Split(shell.Cmd, " ")
 		for i := 1; i < len(args); i++ {
 			args[i] = strings.ReplaceAll(args[i], "${BUILDDIR}", ctx.BuildDir)
+			args[i] = strings.ReplaceAll(args[i], "${ARCH}", ctx.Target.KernelArch)
 		}
 		if args[0] == "make" {
 			if err := ctx.Make(args[1:]...); err != nil {
diff --git a/tools/syz-kconf/parser.go b/tools/syz-kconf/parser.go
index 0f7d330a0..6f46151ed 100644
--- a/tools/syz-kconf/parser.go
+++ b/tools/syz-kconf/parser.go
@@ -83,33 +83,41 @@ type rawFile struct {
 	Config   []yaml.Node
 }
 
-func parseMainSpec(file string) ([]*Instance, error) {
+func parseMainSpec(file string) ([]*Instance, []string, error) {
 	data, err := ioutil.ReadFile(file)
 	if err != nil {
-		return nil, fmt.Errorf("failed to read config file: %v", err)
+		return nil, nil, fmt.Errorf("failed to read config file: %v", err)
 	}
 	dec := yaml.NewDecoder(bytes.NewReader(data))
 	dec.KnownFields(true)
 	raw := new(rawMain)
 	if err := dec.Decode(raw); err != nil {
-		return nil, fmt.Errorf("failed to parse %v: %v", file, err)
+		return nil, nil, fmt.Errorf("failed to parse %v: %v", file, err)
 	}
+	var unusedFeatures []string
 	var instances []*Instance
 	for _, inst := range raw.Instances {
 		for name, features := range inst {
+			if name == "_" {
+				unusedFeatures = features
+				continue
+			}
 			inst, err := parseInstance(name, filepath.Dir(file), features, raw.Includes)
 			if err != nil {
-				return nil, err
+				return nil, nil, err
 			}
 			instances = append(instances, inst)
+			if constraintsInclude(features, featBaseline) {
+				continue
+			}
 			inst, err = parseInstance(name+"-base", filepath.Dir(file), append(features, featBaseline), raw.Includes)
 			if err != nil {
-				return nil, err
+				return nil, nil, err
 			}
 			instances = append(instances, inst)
 		}
 	}
-	return instances, nil
+	return instances, unusedFeatures, nil
 }
 
 func parseInstance(name, configDir string, features []string, includes []map[string][]string) (*Instance, error) {