cpu: don't panic on error reading /proc/self/auxv
On Android /proc/self/auxv is not readable, leading to a panic in init.
Instead of panic'ing in this case, introduce the Initialized global bool
to report whether the CPU features were initialized i.e. /proc/self/auxv
was successfullly read.
Fixes golang/go#30413
Change-Id: Ib520f202990614a76bceb0bf9d19a88eadd13e10
Reviewed-on: https://go-review.googlesource.com/c/164057
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/cpu/cpu.go b/cpu/cpu.go
index 6b0034e..e3a2c4c 100644
--- a/cpu/cpu.go
+++ b/cpu/cpu.go
@@ -6,6 +6,13 @@
// various CPU architectures.
package cpu
+// Initialized reports whether the CPU features were initialized.
+//
+// For some GOOS/GOARCH combinations initialization of the CPU features depends
+// on reading an operating specific file, e.g. /proc/self/auxv on linux/arm
+// Initialized will report false if reading the file fails.
+var Initialized bool
+
// CacheLinePad is used to pad structs to avoid false sharing.
type CacheLinePad struct{ _ [cacheLineSize]byte }
diff --git a/cpu/cpu_linux.go b/cpu/cpu_linux.go
index 33b61e5..76b5f50 100644
--- a/cpu/cpu_linux.go
+++ b/cpu/cpu_linux.go
@@ -28,7 +28,9 @@
func init() {
buf, err := ioutil.ReadFile(procAuxv)
if err != nil {
- panic("read proc auxv failed: " + err.Error())
+ // e.g. on android /proc/self/auxv is not accessible, so silently
+ // ignore the error and leave Initialized = false
+ return
}
bo := hostByteOrder()
@@ -52,4 +54,6 @@
}
}
doinit()
+
+ Initialized = true
}
diff --git a/cpu/cpu_test.go b/cpu/cpu_test.go
index e4b0f0d..c0d8f64 100644
--- a/cpu/cpu_test.go
+++ b/cpu/cpu_test.go
@@ -13,6 +13,9 @@
func TestAMD64minimalFeatures(t *testing.T) {
if runtime.GOARCH == "amd64" {
+ if !cpu.Initialized {
+ t.Fatal("Initialized expected true, got false")
+ }
if !cpu.X86.HasSSE2 {
t.Fatal("HasSSE2 expected true, got false")
}
diff --git a/cpu/cpu_x86.go b/cpu/cpu_x86.go
index 2b3ca2e..d70d317 100644
--- a/cpu/cpu_x86.go
+++ b/cpu/cpu_x86.go
@@ -9,6 +9,8 @@
const cacheLineSize = 64
func init() {
+ Initialized = true
+
maxID, _, _, _ := cpuid(0, 0)
if maxID < 1 {
