chacha/asm/chacha-ppc.pl: improve POWER8 performance by 15%.

This comes at cost of minor 2.5% regression on G4, which is reasonable
trade-off. [Further improve compliance with ABI requirements.]

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6406)

diff --git a/crypto/chacha/asm/chacha-ppc.pl b/crypto/chacha/asm/chacha-ppc.pl
index 6dd05819adaf289007b35ac0ece444232964a494..88746fefc59fbf8247c7f601b95c93378f3b2cf1 100755 (executable)
--- a/crypto/chacha/asm/chacha-ppc.pl
+++ b/crypto/chacha/asm/chacha-ppc.pl
@@ -23,11 +23,11 @@
 #                      IALU/gcc-4.x    3xAltiVec+1xIALU
 #
 # Freescale e300       13.6/+115%      -
-# PPC74x0/G4e          6.81/+310%      3.72
+# PPC74x0/G4e          6.81/+310%      3.81
 # PPC970/G5            9.29/+160%      ?
-# POWER7               8.62/+61%       3.38
-# POWER8               8.70/+51%       3.36
-# POWER9               8.80/+29%       4.50(*)
+# POWER7               8.62/+61%       3.35
+# POWER8               8.70/+51%       2.91
+# POWER9               8.80/+29%       4.44(*)
 #
 # (*)  this is trade-off result, it's possible to improve it, but
 #      then it would negatively affect all others;
@@ -398,12 +398,12 @@ ___
 my ($A0,$B0,$C0,$D0,$A1,$B1,$C1,$D1,$A2,$B2,$C2,$D2)
                                = map("v$_",(0..11));
 my @K                          = map("v$_",(12..17));
-my ($FOUR,$sixteen,$twenty4)   = map("v$_",(18..20));
-my ($inpperm,$outperm,$outmask)        = map("v$_",(21..23));
-my @D                          = map("v$_",(24..28));
+my ($FOUR,$sixteen,$twenty4)   = map("v$_",(18..19,23));
+my ($inpperm,$outperm,$outmask)        = map("v$_",(24..26));
+my @D                          = map("v$_",(27..31));
 my ($twelve,$seven,$T0,$T1) = @D;
 
-my $FRAME=$LOCALS+64+10*16+18*$SIZE_T; # 10*16 is for v20-v28 offload
+my $FRAME=$LOCALS+64+10*16+18*$SIZE_T; # 10*16 is for v23-v31 offload
 
 sub VMXROUND {
 my $odd = pop;
@@ -445,22 +445,22 @@ $code.=<<___;
        li      r10,`15+$LOCALS+64`
        li      r11,`31+$LOCALS+64`
        mfspr   r12,256
-       stvx    v20,r10,$sp
+       stvx    v23,r10,$sp
        addi    r10,r10,32
-       stvx    v21,r11,$sp
+       stvx    v24,r11,$sp
        addi    r11,r11,32
-       stvx    v22,r10,$sp
+       stvx    v25,r10,$sp
        addi    r10,r10,32
-       stvx    v23,r11,$sp
+       stvx    v26,r11,$sp
        addi    r11,r11,32
-       stvx    v24,r10,$sp
+       stvx    v27,r10,$sp
        addi    r10,r10,32
-       stvx    v25,r11,$sp
+       stvx    v28,r11,$sp
        addi    r11,r11,32
-       stvx    v26,r10,$sp
+       stvx    v29,r10,$sp
        addi    r10,r10,32
-       stvx    v27,r11,$sp
-       stvx    v28,r10,$sp
+       stvx    v30,r11,$sp
+       stvx    v31,r10,$sp
        stw     r12,`$FRAME-$SIZE_T*18-4`($sp)  # save vrsave
        $PUSH   r14,`$FRAME-$SIZE_T*18`($sp)
        $PUSH   r15,`$FRAME-$SIZE_T*17`($sp)
@@ -480,7 +480,7 @@ $code.=<<___;
        $PUSH   r29,`$FRAME-$SIZE_T*3`($sp)
        $PUSH   r30,`$FRAME-$SIZE_T*2`($sp)
        $PUSH   r31,`$FRAME-$SIZE_T*1`($sp)
-       li      r12,-8
+       li      r12,-4096+511
        $PUSH   r0, `$FRAME+$LRSAVE`($sp)
        mtspr   256,r12                         # preserve 29 AltiVec registers
 
@@ -588,9 +588,13 @@ ___
        my @thread3=&ROUND(0,4,8,12);
 
        foreach (@thread0) {
-               eval;                   eval(shift(@thread3));
-               eval(shift(@thread1));  eval(shift(@thread3));
-               eval(shift(@thread2));  eval(shift(@thread3));
+               eval;
+               eval(shift(@thread1));
+               eval(shift(@thread2));
+
+               eval(shift(@thread3));
+               eval(shift(@thread3));
+               eval(shift(@thread3));
        }
        foreach (@thread3) { eval; }
 
@@ -600,9 +604,13 @@ ___
        @thread3=&ROUND(0,5,10,15);
 
        foreach (@thread0) {
-               eval;                   eval(shift(@thread3));
-               eval(shift(@thread1));  eval(shift(@thread3));
-               eval(shift(@thread2));  eval(shift(@thread3));
+               eval;
+               eval(shift(@thread1));
+               eval(shift(@thread2));
+
+               eval(shift(@thread3));
+               eval(shift(@thread3));
+               eval(shift(@thread3));
        }
        foreach (@thread3) { eval; }
 $code.=<<___;
@@ -843,22 +851,22 @@ Ldone_vmx:
        li      r10,`15+$LOCALS+64`
        li      r11,`31+$LOCALS+64`
        mtspr   256,r12                         # restore vrsave
-       lvx     v20,r10,$sp
+       lvx     v23,r10,$sp
        addi    r10,r10,32
-       lvx     v21,r11,$sp
+       lvx     v24,r11,$sp
        addi    r11,r11,32
-       lvx     v22,r10,$sp
+       lvx     v25,r10,$sp
        addi    r10,r10,32
-       lvx     v23,r11,$sp
+       lvx     v26,r11,$sp
        addi    r11,r11,32
-       lvx     v24,r10,$sp
+       lvx     v27,r10,$sp
        addi    r10,r10,32
-       lvx     v25,r11,$sp
+       lvx     v28,r11,$sp
        addi    r11,r11,32
-       lvx     v26,r10,$sp
+       lvx     v29,r10,$sp
        addi    r10,r10,32
-       lvx     v27,r11,$sp
-       lvx     v28,r10,$sp
+       lvx     v30,r11,$sp
+       lvx     v31,r10,$sp
        $POP    r0, `$FRAME+$LRSAVE`($sp)
        $POP    r14,`$FRAME-$SIZE_T*18`($sp)
        $POP    r15,`$FRAME-$SIZE_T*17`($sp)