#! /usr/bin/env perl
# Copyright 2010-2016 The OpenSSL Project Authors. All Rights Reserved.
#
# Licensed under the OpenSSL license (the "License"). You may not use
# this file except in compliance with the License. You can obtain a copy
# in the file LICENSE in the source distribution or at
# https://www.openssl.org/source/license.html
# ====================================================================
# Written by Andy Polyakov <appro@openssl.org> for the OpenSSL
# project. The module is, however, dual licensed under OpenSSL and
# CRYPTOGAMS licenses depending on where you obtain it. For further
# details see http://www.openssl.org/~appro/cryptogams/.
# ====================================================================
# This file was adapted to AArch64 from the 32-bit version in ghash-armv4.pl. It
# implements the multiplication algorithm described in:
#
# Câmara, D.; Gouvêa, C. P. L.; López, J. & Dahab, R.: Fast Software
# Polynomial Multiplication on ARM Processors using the NEON Engine.
#
# http://conradoplg.cryptoland.net/files/2010/12/mocrysen13.pdf
#
# The main distinction to keep in mind between 32-bit NEON and AArch64 SIMD is
# AArch64 cannot compute over the upper halves of SIMD registers. In 32-bit
# NEON, the low and high halves of the 128-bit register q0 are accessible as
# 64-bit registers d0 and d1, respectively. In AArch64, dN is the lower half of
# vN. Where the 32-bit version would use the upper half, this file must keep
# halves in separate registers.
#
# The other distinction is in syntax. 32-bit NEON embeds lane information in the
# instruction name, while AArch64 uses suffixes on the registers. For instance,
# left-shifting 64-bit lanes of a SIMD register in 32-bit would be written:
#
# vshl.i64 q0, q0, #1
#
# in 64-bit, it would be written:
#
# shl v0.2d, v0.2d, #1
#
# See Programmer's Guide for ARMv8-A, section 7 for details.
# http://infocenter.arm.com/help/topic/com.arm.doc.den0024a/DEN0024A_v8_architecture_PG.pdf
#
# Finally, note the 8-bit and 64-bit polynomial multipliers in AArch64 differ
# only by suffix. pmull vR.8h, vA.8b, vB.8b multiplies eight 8-bit polynomials
# and is always available. pmull vR.1q, vA.1d, vB.1d multiplies a 64-bit
# polynomial and is conditioned on the PMULL extension. This file emulates the
# latter with the former.
use strict;
my $flavour = shift;
my $output;
if ($flavour=~/\w[\w\-]*\.\w+$/) { $output=$flavour; undef $flavour; }
else { while (($output=shift) && ($output!~/\w[\w\-]*\.\w+$/)) {} }
if ($flavour && $flavour ne "void") {
$0 =~ m/(.*[\/\\])[^\/\\]+$/;
my $dir = $1;
my $xlate;
( $xlate="${dir}arm-xlate.pl" and -f $xlate ) or
( $xlate="${dir}../../../perlasm/arm-xlate.pl" and -f $xlate) or
die "can't locate arm-xlate.pl";
open STDOUT,"| \"$^X\" $xlate $flavour $output";
} else {
open STDOUT,">$output";
}
my ($Xi, $Htbl, $inp, $len) = map("x$_", (0..3)); # argument block
my ($Xl, $Xm, $Xh, $INlo, $INhi) = map("v$_", (0..4));
my ($Hlo, $Hhi, $Hhl) = map("v$_", (5..7));
# d8-d15 are callee-saved, so avoid v8-v15. AArch64 SIMD has plenty of registers
# to spare.
my ($t0, $t1, $t2, $t3) = map("v$_", (16..19));
my ($t0l_t1l, $t0h_t1h, $t2l_t3l, $t2h_t3h) = map("v$_", (20..23));
my ($k48_k32, $k16_k0) = map("v$_", (24..25));
my $code = "";
# clmul64x64 emits code which emulates pmull $r.1q, $a.1d, $b.1d. $r, $a, and $b
# must be distinct from $t* and $k*. $t* are clobbered by the emitted code.
sub clmul64x64 {
my ($r, $a, $b) = @_;
$code .= <<___;
ext $t0.8b, $a.8b, $a.8b, #1 // A1
pmull $t0.8h, $t0.8b, $b.8b // F = A1*B
ext $r.8b, $b.8b, $b.8b, #1 // B1
pmull $r.8h, $a.8b, $r.8b // E = A*B1
ext $t1.8b, $a.8b, $a.8b, #2 // A2
pmull $t1.8h, $t1.8b, $b.8b // H = A2*B
ext $t3.8b, $b.8b, $b.8b, #2 // B2
pmull $t3.8h, $a.8b, $t3.8b // G = A*B2
ext $t2.8b, $a.8b, $a.8b, #3 // A3
eor $t0.16b, $t0.16b, $r.16b // L = E + F
pmull $t2.8h, $t2.8b, $b.8b // J = A3*B
ext $r.8b, $b.8b, $b.8b, #3 // B3
eor $t1.16b, $t1.16b, $t3.16b // M = G + H
pmull $r.8h, $a.8b, $r.8b // I = A*B3
// Here we diverge from the 32-bit version. It computes the following
// (instructions reordered for clarity):
//
// veor \$t0#lo, \$t0#lo, \$t0#hi @ t0 = P0 + P1 (L)
// vand \$t0#hi, \$t0#hi, \$k48
// veor \$t0#lo, \$t0#lo, \$t0#hi
//
// veor \$t1#lo, \$t1#lo, \$t1#hi @ t1 = P2 + P3 (M)
// vand \$t1#hi, \$t1#hi, \$k32
// veor \$t1#lo, \$t1#lo, \$t1#hi
//
// veor \$t2#lo, \$t2#lo, \$t2#hi @ t2 = P4 + P5 (N)
// vand \$t2#hi, \$t2#hi, \$k16
// veor \$t2#lo, \$t2#lo, \$t2#hi
//
// veor \$t3#lo, \$t3#lo, \$t3#hi @ t3 = P6 + P7 (K)
// vmov.i64 \$t3#hi, #0
//
// \$kN is a mask with the bottom N bits set. AArch64 cannot compute on
// upper halves of SIMD registers, so we must split each half into
// separate registers. To compensate, we pair computations up and
// parallelize.
ext $t3.8b, $b.8b, $b.8b, #4 // B4
eor $t2.16b, $t2.16b, $r.16b // N = I + J
pmull $t3.8h, $a.8b, $t3.8b // K = A*B4
// This can probably be scheduled more efficiently. For now, we just
// pair up independent instructions.
zip1 $t0l_t1l.2d, $t0.2d, $t1.2d
zip1 $t2l_t3l.2d, $t2.2d, $t3.2d
zip2 $t0h_t1h.2d, $t0.2d, $t1.2d
zip2 $t2h_t3h.2d, $t2.2d, $t3.2d
eor $t0l_t1l.16b, $t0l_t1l.16b, $t0h_t1h.16b
eor $t2l_t3l.16b, $t2l_t3l.16b, $t2h_t3h.16b
and $t0h_t1h.16b, $t0h_t1h.16b, $k48_k32.16b
and $t2h_t3h.16b, $t2h_t3h.16b, $k16_k0.16b
eor $t0l_t1l.16b, $t0l_t1l.16b, $t0h_t1h.16b
eor $t2l_t3l.16b, $t2l_t3l.16b, $t2h_t3h.16b
zip1 $t0.2d, $t0l_t1l.2d, $t0h_t1h.2d
zip1 $t2.2d, $t2l_t3l.2d, $t2h_t3h.2d
zip2 $t1.2d, $t0l_t1l.2d, $t0h_t1h.2d
zip2 $t3.2d, $t2l_t3l.2d, $t2h_t3h.2d
ext $t0.16b, $t0.16b, $t0.16b, #15 // t0 = t0 << 8
ext $t1.16b, $t1.16b, $t1.16b, #14 // t1 = t1 << 16
pmull $r.8h, $a.8b, $b.8b // D = A*B
ext $t3.16b, $t3.16b, $t3.16b, #12 // t3 = t3 << 32
ext $t2.16b, $t2.16b, $t2.16b, #13 // t2 = t2 << 24
eor $t0.16b, $t0.16b, $t1.16b
eor $t2.16b, $t2.16b, $t3.16b
eor $r.16b, $r.16b, $t0.16b
eor $r.16b, $r.16b, $t2.16b
___
}
$code .= <<___;
.text
.global gcm_init_neon
.type gcm_init_neon,%function
.align 4
gcm_init_neon:
// This function is adapted from gcm_init_v8. xC2 is t3.
ld1 {$t1.2d}, [x1] // load H
movi $t3.16b, #0xe1
shl $t3.2d, $t3.2d, #57 // 0xc2.0
ext $INlo.16b, $t1.16b, $t1.16b, #8
ushr $t2.2d, $t3.2d, #63
dup $t1.4s, $t1.s[1]
ext $t0.16b, $t2.16b, $t3.16b, #8 // t0=0xc2....01
ushr $t2.2d, $INlo.2d, #63
sshr $t1.4s, $t1.4s, #31 // broadcast carry bit
and $t2.16b, $t2.16b, $t0.16b
shl $INlo.2d, $INlo.2d, #1
ext $t2.16b, $t2.16b, $t2.16b, #8
and $t0.16b, $t0.16b, $t1.16b
orr $INlo.16b, $INlo.16b, $t2.16b // H<<<=1
eor $Hlo.16b, $INlo.16b, $t0.16b // twisted H
st1 {$Hlo.2d}, [x0] // store Htable[0]
ret
.size gcm_init_neon,.-gcm_init_neon
.global gcm_gmult_neon
.type gcm_gmult_neon,%function
.align 4
gcm_gmult_neon:
ld1 {$INlo.16b}, [$Xi] // load Xi
ld1 {$Hlo.1d}, [$Htbl], #8 // load twisted H
ld1 {$Hhi.1d}, [$Htbl]
adrp x9, :pg_hi21:.Lmasks // load constants
add x9, x9, :lo12:.Lmasks
ld1 {$k48_k32.2d, $k16_k0.2d}, [x9]
rev64 $INlo.16b, $INlo.16b // byteswap Xi
ext $INlo.16b, $INlo.16b, $INlo.16b, #8
eor $Hhl.8b, $Hlo.8b, $Hhi.8b // Karatsuba pre-processing
mov $len, #16
b .Lgmult_neon
.size gcm_gmult_neon,.-gcm_gmult_neon
.global gcm_ghash_neon
.type gcm_ghash_neon,%function
.align 4
gcm_ghash_neon:
ld1 {$Xl.16b}, [$Xi] // load Xi
ld1 {$Hlo.1d}, [$Htbl], #8 // load twisted H
ld1 {$Hhi.1d}, [$Htbl]
adrp x9, :pg_hi21:.Lmasks // load constants
add x9, x9, :lo12:.Lmasks
ld1 {$k48_k32.2d, $k16_k0.2d}, [x9]
rev64 $Xl.16b, $Xl.16b // byteswap Xi
ext $Xl.16b, $Xl.16b, $Xl.16b, #8
eor $Hhl.8b, $Hlo.8b, $Hhi.8b // Karatsuba pre-processing
.Loop_neon:
ld1 {$INlo.16b}, [$inp], #16 // load inp
rev64 $INlo.16b, $INlo.16b // byteswap inp
ext $INlo.16b, $INlo.16b, $INlo.16b, #8
eor $INlo.16b, $INlo.16b, $Xl.16b // inp ^= Xi
.Lgmult_neon:
// Split the input into $INlo and $INhi. (The upper halves are unused,
// so it is okay to leave them alone.)
ins $INhi.d[0], $INlo.d[1]
___
&clmul64x64 ($Xl, $Hlo, $INlo); # H.lo·Xi.lo
$code .= <<___;
eor $INlo.8b, $INlo.8b, $INhi.8b // Karatsuba pre-processing
___
&clmul64x64 ($Xm, $Hhl, $INlo); # (H.lo+H.hi)·(Xi.lo+Xi.hi)
&clmul64x64 ($Xh, $Hhi, $INhi); # H.hi·Xi.hi
$code .= <<___;
ext $t0.16b, $Xl.16b, $Xh.16b, #8
eor $Xm.16b, $Xm.16b, $Xl.16b // Karatsuba post-processing
eor $Xm.16b, $Xm.16b, $Xh.16b
eor $Xm.16b, $Xm.16b, $t0.16b // Xm overlaps Xh.lo and Xl.hi
ins $Xl.d[1], $Xm.d[0] // Xh|Xl - 256-bit result
// This is a no-op due to the ins instruction below.
// ins $Xh.d[0], $Xm.d[1]
// equivalent of reduction_avx from ghash-x86_64.pl
shl $t1.2d, $Xl.2d, #57 // 1st phase
shl $t2.2d, $Xl.2d, #62
eor $t2.16b, $t2.16b, $t1.16b //
shl $t1.2d, $Xl.2d, #63
eor $t2.16b, $t2.16b, $t1.16b //
// Note Xm contains {Xl.d[1], Xh.d[0]}.
eor $t2.16b, $t2.16b, $Xm.16b
ins $Xl.d[1], $t2.d[0] // Xl.d[1] ^= t2.d[0]
ins $Xh.d[0], $t2.d[1] // Xh.d[0] ^= t2.d[1]
ushr $t2.2d, $Xl.2d, #1 // 2nd phase
eor $Xh.16b, $Xh.16b,$Xl.16b
eor $Xl.16b, $Xl.16b,$t2.16b //
ushr $t2.2d, $t2.2d, #6
ushr $Xl.2d, $Xl.2d, #1 //
eor $Xl.16b, $Xl.16b, $Xh.16b //
eor $Xl.16b, $Xl.16b, $t2.16b //
subs $len, $len, #16
bne .Loop_neon
rev64 $Xl.16b, $Xl.16b // byteswap Xi and write
ext $Xl.16b, $Xl.16b, $Xl.16b, #8
st1 {$Xl.16b}, [$Xi]
ret
.size gcm_ghash_neon,.-gcm_ghash_neon
.section .rodata
.align 4
.Lmasks:
.quad 0x0000ffffffffffff // k48
.quad 0x00000000ffffffff // k32
.quad 0x000000000000ffff // k16
.quad 0x0000000000000000 // k0
.asciz "GHASH for ARMv8, derived from ARMv4 version by <appro\@openssl.org>"
.align 2
___
foreach (split("\n",$code)) {
s/\`([^\`]*)\`/eval $1/geo;
print $_,"\n";
}
close STDOUT; # enforce flush