cpuinfo: parse arm64 CPU implementer, variant, and part

cpuinfo.go

@@ -187,6 +187,24 @@ func parseCPUInfoX86(info []byte) ([]CPUInfo, error) {
 	return cpuinfo, nil
 }
 
+func formatSteppingARM(variant, revision string) string {
+	if variant == "" && revision == "" {
+		return ""
+	}
+	varNum, errV := strconv.ParseUint(variant, 0, 64)
+	revNum, errR := strconv.ParseUint(revision, 0, 64)
+	if errV == nil && errR == nil {
+		return fmt.Sprintf("r%dp%d", varNum, revNum)
+	}
+	if errV == nil {
+		return fmt.Sprintf("r%d", varNum)
+	}
+	if errR == nil {
+		return fmt.Sprintf("p%d", revNum)
+	}
+	return fmt.Sprintf("r%sp%s", variant, revision)
+}
+
 func parseCPUInfoARM(info []byte) ([]CPUInfo, error) {
 	scanner := bufio.NewScanner(bytes.NewReader(info))
 
@@ -199,6 +217,8 @@ func parseCPUInfoARM(info []byte) ([]CPUInfo, error) {
 	cpuinfo := []CPUInfo{}
 	featuresLine := ""
 	commonCPUInfo := CPUInfo{}
+	variants := make(map[int]string)
+	revisions := make(map[int]string)
 	i := 0
 	if strings.TrimSpace(field[0]) == "Processor" {
 		commonCPUInfo = CPUInfo{ModelName: field[1]}
@@ -212,12 +232,26 @@ func parseCPUInfoARM(info []byte) ([]CPUInfo, error) {
 		cpuinfo = []CPUInfo{firstcpu}
 	}
 
+	updateStepping := func(idx int) {
+		v := variants[idx]
+		r := revisions[idx]
+		stepping := formatSteppingARM(v, r)
+		if idx == -1 {
+			commonCPUInfo.Stepping = stepping
+		} else {
+			cpuinfo[idx].Stepping = stepping
+		}
+	}
+
 	for scanner.Scan() {
 		line := scanner.Text()
 		if !strings.Contains(line, ":") {
 			continue
 		}
 		field := strings.SplitN(line, ": ", 2)
+		if len(field) < 2 {
+			continue
+		}
 		switch strings.TrimSpace(field[0]) {
 		case "processor":
 			cpuinfo = append(cpuinfo, commonCPUInfo) // start of the next processor
@@ -241,12 +275,79 @@ func parseCPUInfoARM(info []byte) ([]CPUInfo, error) {
 		case "Features":
 			featuresLine = line
 		case "model name":
-			cpuinfo[i].ModelName = field[1]
+			if i == -1 {
+				commonCPUInfo.ModelName = field[1]
+			} else {
+				cpuinfo[i].ModelName = field[1]
+			}
+		case "CPU implementer", "cpu implementer":
+			val := strings.TrimSpace(field[1])
+			if i == -1 {
+				commonCPUInfo.VendorID = val
+			} else {
+				cpuinfo[i].VendorID = val
+			}
+		case "CPU architecture", "cpu architecture":
+			val := strings.TrimSpace(field[1])
+			if i == -1 {
+				commonCPUInfo.CPUFamily = val
+			} else {
+				cpuinfo[i].CPUFamily = val
+			}
+		case "CPU part", "cpu part":
+			val := strings.TrimSpace(field[1])
+			if i == -1 {
+				commonCPUInfo.Model = val
+			} else {
+				cpuinfo[i].Model = val
+			}
+		case "CPU variant", "cpu variant":
+			val := strings.TrimSpace(field[1])
+			if i == -1 {
+				variants[-1] = val
+				updateStepping(-1)
+			} else {
+				variants[i] = val
+				updateStepping(i)
+			}
+		case "CPU revision", "cpu revision":
+			val := strings.TrimSpace(field[1])
+			if i == -1 {
+				revisions[-1] = val
+				updateStepping(-1)
+			} else {
+				revisions[i] = val
+				updateStepping(i)
+			}
 		}
 	}
-	fields := strings.SplitN(featuresLine, ": ", 2)
-	for i := range cpuinfo {
-		cpuinfo[i].Flags = strings.Fields(fields[1])
+
+	if len(cpuinfo) > 0 && cpuinfo[0].VendorID == "" && cpuinfo[len(cpuinfo)-1].VendorID != "" {
+		last := cpuinfo[len(cpuinfo)-1]
+		for j := range cpuinfo {
+			if cpuinfo[j].VendorID == "" {
+				cpuinfo[j].VendorID = last.VendorID
+			}
+			if cpuinfo[j].CPUFamily == "" {
+				cpuinfo[j].CPUFamily = last.CPUFamily
+			}
+			if cpuinfo[j].Model == "" {
+				cpuinfo[j].Model = last.Model
+			}
+			if cpuinfo[j].Stepping == "" {
+				cpuinfo[j].Stepping = last.Stepping
+			}
+		}
+	}
+
+	if featuresLine != "" {
+		fields := strings.SplitN(featuresLine, ": ", 2)
+		if len(fields) > 1 {
+			flags := strings.Fields(fields[1])
+			for i := range cpuinfo {
+				cpuinfo[i].Flags = flags
+			}
+		}
 	}
 	return cpuinfo, nil
 }