mirror of https://github.com/golang/go.git
53 lines
1.8 KiB
Go
53 lines
1.8 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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// macOS 12 moved these to the hw.optional.arm tree, but as of Go 1.24 we
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// still support macOS 11. See [Determine Encryption Capabilities].
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//
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// [Determine Encryption Capabilities]: https://developer.apple.com/documentation/kernel/1387446-sysctlbyname/determining_instruction_set_characteristics#3918855
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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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ARM64.HasSHA3 = sysctlEnabled([]byte("hw.optional.armv8_2_sha3\x00"))
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ARM64.HasDIT = sysctlEnabled([]byte("hw.optional.arm.FEAT_DIT\x00"))
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// There are no hw.optional sysctl values for the below features on macOS 11
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// to detect their supported state dynamically (although they are available
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// in the hw.optional.arm tree on macOS 12). Assume the CPU features that
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// Apple Silicon M1 supports to be available on all future iterations.
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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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