// Copyright 2022 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build linux && arm64
package cpu
import (
"errors"
"io"
"os"
"strings"
)
func readLinuxProcCPUInfo() error {
f, err := os.Open("/proc/cpuinfo")
if err != nil {
return err
}
defer f.Close()
var buf [1 << 10]byte // enough for first CPU
n, err := io.ReadFull(f, buf[:])
if err != nil && err != io.ErrUnexpectedEOF {
return err
}
in := string(buf[:n])
const features = "\nFeatures : "
i := strings.Index(in, features)
if i == -1 {
return errors.New("no CPU features found")
}
in = in[i+len(features):]
if i := strings.Index(in, "\n"); i != -1 {
in = in[:i]
}
m := map[string]*bool{}
initOptions() // need it early here; it's harmless to call twice
for _, o := range options {
m[o.Name] = o.Feature
}
// The EVTSTRM field has alias "evstrm" in Go, but Linux calls it "evtstrm".
m["evtstrm"] = &ARM64.HasEVTSTRM
for _, f := range strings.Fields(in) {
if p, ok := m[f]; ok {
*p = true
}
}
return nil
}