Michael Munday
0091315ad7
Use the recently added CPU feature detection API rather than custom assembly. This will need to be updated to use 'internal/cpu' when the package is revendored into std. Change-Id: Ia99c51c7409fe4fabcd88fdf5ff19772c1ca2257 Reviewed-on: https://go-review.googlesource.com/c/164382 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
43 lines
1.3 KiB
Go
43 lines
1.3 KiB
Go
// Copyright 2018 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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// +build s390x,go1.11,!gccgo,!appengine
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package poly1305
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import (
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"golang.org/x/sys/cpu"
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)
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// poly1305vx is an assembly implementation of Poly1305 that uses vector
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// instructions. It must only be called if the vector facility (vx) is
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// available.
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//go:noescape
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func poly1305vx(out *[16]byte, m *byte, mlen uint64, key *[32]byte)
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// poly1305vmsl is an assembly implementation of Poly1305 that uses vector
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// instructions, including VMSL. It must only be called if the vector facility (vx) is
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// available and if VMSL is supported.
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//go:noescape
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func poly1305vmsl(out *[16]byte, m *byte, mlen uint64, key *[32]byte)
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// Sum generates an authenticator for m using a one-time key and puts the
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// 16-byte result into out. Authenticating two different messages with the same
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// key allows an attacker to forge messages at will.
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func Sum(out *[16]byte, m []byte, key *[32]byte) {
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if cpu.S390X.HasVX {
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var mPtr *byte
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if len(m) > 0 {
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mPtr = &m[0]
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}
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if cpu.S390X.HasVXE && len(m) > 256 {
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poly1305vmsl(out, mPtr, uint64(len(m)), key)
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} else {
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poly1305vx(out, mPtr, uint64(len(m)), key)
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}
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} else {
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sumGeneric(out, m, key)
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}
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}
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