// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package runtime
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import "internal/cpu"
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const (
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_HWCAP_VFP = 1 << 6
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_HWCAP_VFPv3 = 1 << 13
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)
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// AT_HWCAP is not available on FreeBSD-11.1-RELEASE or earlier.
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// Default to mandatory VFP hardware support for arm being available.
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// If AT_HWCAP is available goarmHWCap will be updated in archauxv.
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// TODO(moehrmann) remove once all go supported FreeBSD versions support _AT_HWCAP.
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var goarmHWCap uint = (_HWCAP_VFP | _HWCAP_VFPv3)
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func checkgoarm() {
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// Update cpu.HWCap to match goarmHWCap in case they were not updated in archauxv.
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cpu.HWCap = goarmHWCap
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if goarm > 5 && cpu.HWCap&_HWCAP_VFP == 0 {
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print("runtime: this CPU has no floating point hardware, so it cannot run\n")
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print("this GOARM=", goarm, " binary. Recompile using GOARM=5.\n")
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exit(1)
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}
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if goarm > 6 && cpu.HWCap&_HWCAP_VFPv3 == 0 {
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print("runtime: this CPU has no VFPv3 floating point hardware, so it cannot run\n")
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print("this GOARM=", goarm, " binary. Recompile using GOARM=5 or GOARM=6.\n")
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exit(1)
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}
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// osinit not called yet, so ncpu not set: must use getncpu directly.
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if getncpu() > 1 && goarm < 7 {
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print("runtime: this system has multiple CPUs and must use\n")
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print("atomic synchronization instructions. Recompile using GOARM=7.\n")
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exit(1)
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}
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}
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func archauxv(tag, val uintptr) {
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switch tag {
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case _AT_HWCAP:
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cpu.HWCap = uint(val)
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goarmHWCap = cpu.HWCap
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case _AT_HWCAP2:
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cpu.HWCap2 = uint(val)
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}
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}
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//go:nosplit
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func cputicks() int64 {
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// Currently cputicks() is used in blocking profiler and to seed runtime·fastrand().
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// runtime·nanotime() is a poor approximation of CPU ticks that is enough for the profiler.
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// TODO: need more entropy to better seed fastrand.
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return nanotime()
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}
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