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 7 package poly1305 8 9 // hasVectorFacility reports whether the machine supports 10 // the vector facility (vx). 11 func hasVectorFacility() bool 12 13 // hasVMSLFacility reports whether the machine supports 14 // Vector Multiply Sum Logical (VMSL). 15 func hasVMSLFacility() bool 16 17 var hasVX = hasVectorFacility() 18 var 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 24 func 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 30 func 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. 35 func 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
