mirror of https://go.googlesource.com/go
46 lines
1.3 KiB
Go
46 lines
1.3 KiB
Go
// Copyright 2020 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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//go:build arm64 && darwin && !ios
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package cpu
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import _ "unsafe" // for linkname
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func osInit() {
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ARM64.HasATOMICS = sysctlEnabled([]byte("hw.optional.armv8_1_atomics\x00"))
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ARM64.HasCRC32 = sysctlEnabled([]byte("hw.optional.armv8_crc32\x00"))
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ARM64.HasSHA512 = sysctlEnabled([]byte("hw.optional.armv8_2_sha512\x00"))
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// There are no hw.optional sysctl values for the below features on Mac OS 11.0
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// to detect their supported state dynamically. Assume the CPU features that
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// Apple Silicon M1 supports to be available as a minimal set of features
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// to all Go programs running on darwin/arm64.
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ARM64.HasAES = true
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ARM64.HasPMULL = true
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ARM64.HasSHA1 = true
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ARM64.HasSHA2 = true
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}
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//go:noescape
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func getsysctlbyname(name []byte) (int32, int32)
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// sysctlEnabled should be an internal detail,
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// but widely used packages access it using linkname.
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// Notable members of the hall of shame include:
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// - github.com/bytedance/gopkg
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// - github.com/songzhibin97/gkit
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//
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// Do not remove or change the type signature.
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// See go.dev/issue/67401.
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//
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//go:linkname sysctlEnabled
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func sysctlEnabled(name []byte) bool {
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ret, value := getsysctlbyname(name)
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if ret < 0 {
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return false
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}
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return value > 0
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}
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