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go/src/runtime/os_linux_arm.go
Austin Clements 8174f7fb2b runtime: mlock top of signal stack on Linux 5.2–5.4.1
Linux 5.2 introduced a bug that can corrupt vector registers on return
from a signal if the signal stack isn't faulted in:
https://bugzilla.kernel.org/show_bug.cgi?id=205663

This CL works around this by mlocking the top page of all Go signal
stacks on the affected kernels.

Fixes #35326, #35777

Change-Id: I77c80a2baa4780827633f92f464486caa222295d
Reviewed-on: https://go-review.googlesource.com/c/go/+/209899
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2019-12-05 01:48:14 +00:00

50 lines
1.4 KiB
Go

// Copyright 2009 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.
package runtime
import "internal/cpu"
const (
_HWCAP_VFP = 1 << 6 // introduced in at least 2.6.11
_HWCAP_VFPv3 = 1 << 13 // introduced in 2.6.30
)
func checkgoarm() {
// On Android, /proc/self/auxv might be unreadable and hwcap won't
// reflect the CPU capabilities. Assume that every Android arm device
// has the necessary floating point hardware available.
if GOOS == "android" {
return
}
if goarm > 5 && cpu.HWCap&_HWCAP_VFP == 0 {
print("runtime: this CPU has no floating point hardware, so it cannot run\n")
print("this GOARM=", goarm, " binary. Recompile using GOARM=5.\n")
exit(1)
}
if goarm > 6 && cpu.HWCap&_HWCAP_VFPv3 == 0 {
print("runtime: this CPU has no VFPv3 floating point hardware, so it cannot run\n")
print("this GOARM=", goarm, " binary. Recompile using GOARM=5 or GOARM=6.\n")
exit(1)
}
}
func archauxv(tag, val uintptr) {
switch tag {
case _AT_HWCAP:
cpu.HWCap = uint(val)
case _AT_HWCAP2:
cpu.HWCap2 = uint(val)
}
}
func osArchInit() {}
//go:nosplit
func cputicks() int64 {
// Currently cputicks() is used in blocking profiler and to seed fastrand().
// nanotime() is a poor approximation of CPU ticks that is enough for the profiler.
return nanotime()
}