1// Copyright 2018 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5// +build s390x,go1.11,!gccgo,!appengine 6 7package poly1305 8 9// hasVectorFacility reports whether the machine supports 10// the vector facility (vx). 11func hasVectorFacility() bool 12 13// hasVMSLFacility reports whether the machine supports 14// Vector Multiply Sum Logical (VMSL). 15func hasVMSLFacility() bool 16 17var hasVX = hasVectorFacility() 18var hasVMSL = hasVMSLFacility() 19 20// poly1305vx is an assembly implementation of Poly1305 that uses vector 21// instructions. It must only be called if the vector facility (vx) is 22// available. 23//go:noescape 24func poly1305vx(out *[16]byte, m *byte, mlen uint64, key *[32]byte) 25 26// poly1305vmsl is an assembly implementation of Poly1305 that uses vector 27// instructions, including VMSL. It must only be called if the vector facility (vx) is 28// available and if VMSL is supported. 29//go:noescape 30func poly1305vmsl(out *[16]byte, m *byte, mlen uint64, key *[32]byte) 31 32// Sum generates an authenticator for m using a one-time key and puts the 33// 16-byte result into out. Authenticating two different messages with the same 34// key allows an attacker to forge messages at will. 35func Sum(out *[16]byte, m []byte, key *[32]byte) { 36 if hasVX { 37 var mPtr *byte 38 if len(m) > 0 { 39 mPtr = &m[0] 40 } 41 if hasVMSL && len(m) > 256 { 42 poly1305vmsl(out, mPtr, uint64(len(m)), key) 43 } else { 44 poly1305vx(out, mPtr, uint64(len(m)), key) 45 } 46 } else { 47 sumGeneric(out, m, key) 48 } 49} 50