From 9ee020f8dc7813db82a119058d8f57e70e7e8904 Mon Sep 17 00:00:00 2001
From: Andy Polyakov <appro@openssl.org>
Date: Fri, 1 Dec 2017 13:13:25 +0100
Subject: [PATCH] modes/asm/ghashv8-armx.pl: modulo-schedule loop.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4830)
---
 crypto/modes/asm/ghashv8-armx.pl | 73 ++++++++++++++++++++++++++++++--
 1 file changed, 70 insertions(+), 3 deletions(-)

diff --git a/crypto/modes/asm/ghashv8-armx.pl b/crypto/modes/asm/ghashv8-armx.pl
index ef7c74798d..2498a1d646 100644
--- a/crypto/modes/asm/ghashv8-armx.pl
+++ b/crypto/modes/asm/ghashv8-armx.pl
@@ -423,10 +423,7 @@ gcm_ghash_v8_4x:
 #ifndef __ARMEB__
 	vrev64.8	$Xl,$Xl
 #endif
-	b		.Loop4x
 
-.align	4
-.Loop4x:
 	vld1.64		{$I0-$j3},[$inp],#64
 #ifndef __ARMEB__
 	vrev64.8	$j1,$j1
@@ -461,6 +458,13 @@ gcm_ghash_v8_4x:
 	veor		$Yh,$Yh,$I1
 	veor		$Ym,$Ym,$j1
 
+	subs		$len,$len,#64
+	b.eq		.Ltail4x
+
+	b		.Loop4x
+
+.align	4
+.Loop4x:
 	veor		$t0,$I0,$Xl
 	vext.8		$IN,$t0,$t0,#8
 
@@ -489,9 +493,72 @@ gcm_ghash_v8_4x:
 	veor		$Xl,$Xl,$t2
 	vext.8		$Xl,$Xl,$Xl,#8
 
+	 vld1.64	{$I0-$j3},[$inp],#64
+#ifndef __ARMEB__
+	 vrev64.8	$j1,$j1
+	 vrev64.8	$j2,$j2
+	 vrev64.8	$j3,$j3
+	 vrev64.8	$I0,$I0
+#endif
+	 vext.8		$I3,$j3,$j3,#8
+	 vext.8		$I2,$j2,$j2,#8
+	 vext.8		$I1,$j1,$j1,#8
+
+	 vpmull.p64	$Yl,$H,$I3		@ H·Ii+3
+	 veor		$j3,$j3,$I3
+	 vpmull2.p64	$Yh,$H,$I3
+	 vpmull.p64	$Ym,$Hhl,$j3
+
+	 vpmull.p64	$t0,$H2,$I2		@ H^2·Ii+2
+	 veor		$j2,$j2,$I2
+	 vpmull2.p64	$I2,$H2,$I2
+	 vpmull2.p64	$j2,$Hhl,$j2
+
+	 veor		$Yl,$Yl,$t0
+	 veor		$Yh,$Yh,$I2
+	 veor		$Ym,$Ym,$j2
+
+	 vpmull.p64	$j3,$H3,$I1		@ H^3·Ii+1
+	 veor		$j1,$j1,$I1
+	 vpmull2.p64	$I1,$H3,$I1
+	 vpmull.p64	$j1,$H34,$j1
+
+	 veor		$Yl,$Yl,$j3
+	 veor		$Yh,$Yh,$I1
+	 veor		$Ym,$Ym,$j1
+
 	subs		$len,$len,#64
 	b.ne		.Loop4x
 
+.Ltail4x:
+	veor		$t0,$I0,$Xl
+	vext.8		$IN,$t0,$t0,#8
+
+	vpmull.p64	$Xl,$H4,$IN		@ H^4·(Xi+Ii)
+	veor		$t0,$t0,$IN
+	vpmull2.p64	$Xh,$H4,$IN
+	vpmull2.p64	$Xm,$H34,$t0
+
+	veor		$Xl,$Xl,$Yl
+	veor		$Xh,$Xh,$Yh
+	veor		$Xm,$Xm,$Ym
+
+	vext.8		$t1,$Xl,$Xh,#8		@ Karatsuba post-processing
+	veor		$t2,$Xl,$Xh
+	veor		$Xm,$Xm,$t1
+	veor		$Xm,$Xm,$t2
+
+	vpmull.p64	$t2,$Xl,$xC2		@ 1st phase of reduction
+	vmov		$Xh#lo,$Xm#hi		@ Xh|Xm - 256-bit result
+	vmov		$Xm#hi,$Xl#lo		@ Xm is rotated Xl
+	veor		$Xl,$Xm,$t2
+
+	vext.8		$t2,$Xl,$Xl,#8		@ 2nd phase of reduction
+	vpmull.p64	$Xl,$Xl,$xC2
+	veor		$t2,$t2,$Xh
+	veor		$Xl,$Xl,$t2
+	vext.8		$Xl,$Xl,$Xl,#8
+
 #ifndef __ARMEB__
 	vrev64.8	$Xl,$Xl
 #endif
-- 
2.34.1