sha512-ppc.pl mutli-thread safety fix.

diff --git a/crypto/sha/asm/sha512-ppc.pl b/crypto/sha/asm/sha512-ppc.pl
index 877d172215963bf251a8bf1d48047f96b114cda2..087faab866059e0ca9d5a348a8f1baaf999787e1 100755 (executable)
--- a/crypto/sha/asm/sha512-ppc.pl
+++ b/crypto/sha/asm/sha512-ppc.pl
@@ -2,8 +2,9 @@
 
 # ====================================================================
 # Written by Andy Polyakov <appro@fy.chalmers.se> for the OpenSSL
-# project. Rights for redistribution and usage in source and binary
-# forms are granted according to the OpenSSL license.
+# 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/.
 # ====================================================================
 
 # I let hardware handle unaligned input, except on page boundaries
@@ -17,7 +18,21 @@
 # PPC970,gcc-4.0.0     +50%    +38%    |       +40%    +410%(*)
 #
 # (*)  64-bit code in 32-bit application context, which actually is
-#      on TODO list
+#      on TODO list. It should be noted that for safe deployment in
+#      32-bit *mutli-threaded* context asyncronous signals should be
+#      blocked upon entry to SHA512 block routine. This is because
+#      32-bit signaling procedure invalidates upper halves of GPRs.
+#      Context switch procedure preserves them, but not signaling:-(
+
+# Second version is true multi-thread safe. Trouble with the original
+# version was that it was using thread local storage pointer register.
+# Well, it scrupulously preserved it, but the problem would arise the
+# moment asynchronous signal was delivered and signal handler would
+# dereference the TLS pointer. While it's never the case in openssl
+# application or test suite, we have to respect this scenario and not
+# use TLS pointer register. Alternative would be to require caller to
+# block signals prior calling this routine. For the record, in 32-bit
+# context R2 serves as TLS pointer, while in 64-bit context - R13.
 
 $output=shift;
 
@@ -69,24 +84,24 @@ if ($output =~ /512/) {
 $FRAME=32*$SIZE_T;
 
 $sp ="r1";
-$toc="r2";     # zapped by $Tbl
+$toc="r2";
 $ctx="r3";     # zapped by $a0
-$inp="r4";
-$num="r5";     # zapped by $a1
+$inp="r4";     # zapped by $a1
+$num="r5";     # zapped by $t0
 
 $T  ="r0";
-$Tbl="r2";
 $a0 ="r3";
-$a1 ="r5";
-$t0 ="r6";
-$t1 ="r7";
+$a1 ="r4";
+$t0 ="r5";
+$t1 ="r6";
+$Tbl="r7";
 
 $A  ="r8";
 $B  ="r9";
 $C  ="r10";
 $D  ="r11";
 $E  ="r12";
-$F  ="r13";
+$F  ="r13";    $F="r2" if ($SIZE_T==8);# reassigned to exempt TLS pointer
 $G  ="r14";
 $H  ="r15";
 
@@ -94,6 +109,8 @@ $H  ="r15";
 @X=("r16","r17","r18","r19","r20","r21","r22","r23",
     "r24","r25","r26","r27","r28","r29","r30","r31");
 
+$inp="r31";    # reassigned $inp! aliases with @X[15]
+
 sub ROUND_00_15 {
 my ($i,$a,$b,$c,$d,$e,$f,$g,$h)=@_;
 $code.=<<___;
@@ -184,6 +201,7 @@ $func:
        $PUSH   r31,`$FRAME-$SIZE_T*1`($sp)
 
        $LD     $A,`0*$SZ`($ctx)
+       mr      $inp,r4                         ; incarnate $inp
        $LD     $B,`1*$SZ`($ctx)
        $LD     $C,`2*$SZ`($ctx)
        $LD     $D,`3*$SZ`($ctx)
@@ -197,8 +215,9 @@ LPICedup:
        andi.   r0,$inp,3
        bne     Lunaligned
 Laligned:
-       add     $t0,$inp,$num
-       $PUSH   $t0,`$FRAME-$SIZE_T*23`($sp)    ; end pointer
+       add     $num,$inp,$num
+       $PUSH   $num,`$FRAME-$SIZE_T*24`($sp)   ; end pointer
+       $PUSH   $inp,`$FRAME-$SIZE_T*23`($sp)   ; inp pointer
        bl      Lsha2_block_private
 Ldone:
        $POP    r0,`$FRAME-$SIZE_T*21`($sp)
@@ -242,15 +261,17 @@ Lunaligned:
        $UCMP   $num,$t1
        ble-    Laligned                ; didn't cross the page boundary
        subfc   $num,$t1,$num
-       add     $t0,$inp,$t1
-       $PUSH   $num,`$FRAME-$SIZE_T*24`($sp)
-       $PUSH   $t0,`$FRAME-$SIZE_T*23`($sp)    ; end pointer
+       add     $t1,$inp,$t1
+       $PUSH   $num,`$FRAME-$SIZE_T*25`($sp)   ; save real remaining num
+       $PUSH   $t1,`$FRAME-$SIZE_T*24`($sp)    ; intermediate end pointer
+       $PUSH   $inp,`$FRAME-$SIZE_T*23`($sp)   ; inp pointer
        bl      Lsha2_block_private
-       $POP    $num,`$FRAME-$SIZE_T*24`($sp)
+       ; $inp equals to the intermediate end pointer here
+       $POP    $num,`$FRAME-$SIZE_T*25`($sp)   ; restore real remaining num
 Lcross_page:
        li      $t1,`16*$SZ/4`
        mtctr   $t1
-       addi    r20,$sp,$FRAME  ; spot below the frame
+       addi    r20,$sp,$FRAME                  ; aligned spot below the frame
 Lmemcpy:
        lbz     r16,0($inp)
        lbz     r17,1($inp)
@@ -264,15 +285,16 @@ Lmemcpy:
        addi    r20,r20,4
        bdnz    Lmemcpy
 
-       $PUSH   $inp,`$FRAME-$SIZE_T*25`($sp)
-       addi    $inp,$sp,$FRAME
-       addi    $t0,$sp,`$FRAME+16*$SZ`
-       $PUSH   $num,`$FRAME-$SIZE_T*24`($sp)
-       $PUSH   $t0,`$FRAME-$SIZE_T*23`($sp)    ; end pointer
+       $PUSH   $inp,`$FRAME-$SIZE_T*26`($sp)   ; save real inp
+       addi    $t1,$sp,`$FRAME+16*$SZ`         ; fictitious end pointer
+       addi    $inp,$sp,$FRAME                 ; fictitious inp pointer
+       $PUSH   $num,`$FRAME-$SIZE_T*25`($sp)   ; save real num
+       $PUSH   $t1,`$FRAME-$SIZE_T*24`($sp)    ; end pointer
+       $PUSH   $inp,`$FRAME-$SIZE_T*23`($sp)   ; inp pointer
        bl      Lsha2_block_private
-       $POP    $inp,`$FRAME-$SIZE_T*25`($sp)
-       $POP    $num,`$FRAME-$SIZE_T*24`($sp)
-       addic.  $num,$num,`-16*$SZ`
+       $POP    $inp,`$FRAME-$SIZE_T*26`($sp)   ; restore real inp
+       $POP    $num,`$FRAME-$SIZE_T*25`($sp)   ; restore real num
+       addic.  $num,$num,`-16*$SZ`             ; num--
        bne-    Lunaligned
        b       Ldone
 ___
@@ -309,9 +331,10 @@ for(;$i<32;$i++) {
 $code.=<<___;
        bdnz-   Lrounds
 
-       subi    $Tbl,$Tbl,`($rounds-16)*$SZ`
        $POP    $ctx,`$FRAME-$SIZE_T*22`($sp)
-       $POP    $num,`$FRAME-$SIZE_T*23`($sp)   ; end pointer
+       $POP    $inp,`$FRAME-$SIZE_T*23`($sp)   ; inp pointer
+       $POP    $num,`$FRAME-$SIZE_T*24`($sp)   ; end pointer
+       subi    $Tbl,$Tbl,`($rounds-16)*$SZ`    ; rewind Tbl
 
        $LD     r16,`0*$SZ`($ctx)
        $LD     r17,`1*$SZ`($ctx)
@@ -320,9 +343,11 @@ $code.=<<___;
        $LD     r20,`4*$SZ`($ctx)
        $LD     r21,`5*$SZ`($ctx)
        $LD     r22,`6*$SZ`($ctx)
+       addi    $inp,$inp,`16*$SZ`              ; advance inp
        $LD     r23,`7*$SZ`($ctx)
        add     $A,$A,r16
        add     $B,$B,r17
+       $PUSH   $inp,`$FRAME-$SIZE_T*23`($sp)
        add     $C,$C,r18
        $ST     $A,`0*$SZ`($ctx)
        add     $D,$D,r19
@@ -335,7 +360,6 @@ $code.=<<___;
        $ST     $E,`4*$SZ`($ctx)
        add     $H,$H,r23
        $ST     $F,`5*$SZ`($ctx)
-       addi    $inp,$inp,`16*$SZ`
        $ST     $G,`6*$SZ`($ctx)
        $UCMP   $inp,$num
        $ST     $H,`7*$SZ`($ctx)
@@ -349,21 +373,21 @@ $code.=<<___;
 .align 6
 LPICmeup:
        bl      LPIC
+       addi    $Tbl,$Tbl,`64-4`        ; "distance" between . and last nop
        b       LPICedup
        nop
        nop
        nop
        nop
        nop
-       nop
 LPIC:  mflr    $Tbl
-       addi    $Tbl,$Tbl,`64-4`        ; "distance" between bl and last nop
        blr
        nop
        nop
        nop
        nop
        nop
+       nop
 ___
 $code.=<<___ if ($SZ==8);
        .long   0x428a2f98,0xd728ae22,0x71374491,0x23ef65cd