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      1 #!/usr/bin/env perl
      2 #
      3 # ====================================================================
      4 # Written by Andy Polyakov <appro (at] fy.chalmers.se> for the OpenSSL
      5 # project. The module is, however, dual licensed under OpenSSL and
      6 # CRYPTOGAMS licenses depending on where you obtain it. For further
      7 # details see http://www.openssl.org/~appro/cryptogams/.
      8 # ====================================================================
      9 #
     10 # 2.22x RC4 tune-up:-) It should be noted though that my hand [as in
     11 # "hand-coded assembler"] doesn't stand for the whole improvement
     12 # coefficient. It turned out that eliminating RC4_CHAR from config
     13 # line results in ~40% improvement (yes, even for C implementation).
     14 # Presumably it has everything to do with AMD cache architecture and
     15 # RAW or whatever penalties. Once again! The module *requires* config
     16 # line *without* RC4_CHAR! As for coding "secret," I bet on partial
     17 # register arithmetics. For example instead of 'inc %r8; and $255,%r8'
     18 # I simply 'inc %r8b'. Even though optimization manual discourages
     19 # to operate on partial registers, it turned out to be the best bet.
     20 # At least for AMD... How IA32E would perform remains to be seen...
     21 
     22 # As was shown by Marc Bevand reordering of couple of load operations
     23 # results in even higher performance gain of 3.3x:-) At least on
     24 # Opteron... For reference, 1x in this case is RC4_CHAR C-code
     25 # compiled with gcc 3.3.2, which performs at ~54MBps per 1GHz clock.
     26 # Latter means that if you want to *estimate* what to expect from
     27 # *your* Opteron, then multiply 54 by 3.3 and clock frequency in GHz.
     28 
     29 # Intel P4 EM64T core was found to run the AMD64 code really slow...
     30 # The only way to achieve comparable performance on P4 was to keep
     31 # RC4_CHAR. Kind of ironic, huh? As it's apparently impossible to
     32 # compose blended code, which would perform even within 30% marginal
     33 # on either AMD and Intel platforms, I implement both cases. See
     34 # rc4_skey.c for further details...
     35 
     36 # P4 EM64T core appears to be "allergic" to 64-bit inc/dec. Replacing
     37 # those with add/sub results in 50% performance improvement of folded
     38 # loop...
     39 
     40 # As was shown by Zou Nanhai loop unrolling can improve Intel EM64T
     41 # performance by >30% [unlike P4 32-bit case that is]. But this is
     42 # provided that loads are reordered even more aggressively! Both code
     43 # pathes, AMD64 and EM64T, reorder loads in essentially same manner
     44 # as my IA-64 implementation. On Opteron this resulted in modest 5%
     45 # improvement [I had to test it], while final Intel P4 performance
     46 # achieves respectful 432MBps on 2.8GHz processor now. For reference.
     47 # If executed on Xeon, current RC4_CHAR code-path is 2.7x faster than
     48 # RC4_INT code-path. While if executed on Opteron, it's only 25%
     49 # slower than the RC4_INT one [meaning that if CPU -arch detection
     50 # is not implemented, then this final RC4_CHAR code-path should be
     51 # preferred, as it provides better *all-round* performance].
     52 
     53 # Intel Core2 was observed to perform poorly on both code paths:-( It
     54 # apparently suffers from some kind of partial register stall, which
     55 # occurs in 64-bit mode only [as virtually identical 32-bit loop was
     56 # observed to outperform 64-bit one by almost 50%]. Adding two movzb to
     57 # cloop1 boosts its performance by 80%! This loop appears to be optimal
     58 # fit for Core2 and therefore the code was modified to skip cloop8 on
     59 # this CPU.
     60 
     61 #
     62 # OpenSolaris OS modifications
     63 #
     64 # Sun elects to use this software under the BSD license.
     65 #
     66 # This source originates from OpenSSL file rc4-x86_64.pl at
     67 # ftp://ftp.openssl.org/snapshot/openssl-0.9.8-stable-SNAP-20080131.tar.gz
     68 # (presumably for future OpenSSL release 0.9.8h), with these changes:
     69 #
     70 # 1. Added some comments, "use strict", and declared all variables.
     71 #
     72 # 2. Added OpenSolaris ENTRY_NP/SET_SIZE macros from
     73 # /usr/include/sys/asm_linkage.h.
     74 #
     75 # 3. Changed function name from RC4() to arcfour_crypt_asm() and RC4_set_key()
     76 # to arcfour_key_init(), and changed the parameter order for both to that
     77 # used by OpenSolaris.
     78 #
     79 # 4. The current method of using cpuid feature bits 20 (NX) or 28 (HTT) from
     80 # function OPENSSL_ia32_cpuid() to distinguish Intel/AMD does not work for
     81 # some newer AMD64 processors, as these bits are set on both Intel EM64T
     82 # processors and newer AMD64 processors.  I replaced this with C code
     83 # (function arcfour_crypt_on_intel()) to call cpuid_getvendor()
     84 # when executing in the kernel and getisax() when executing in userland.
     85 #
     86 # 5. Set a new field in the key structure, key->flag to 0 for AMD AMD64
     87 # and 1 for Intel EM64T.  This is to select the most-efficient arcfour_crypt()
     88 # function to use.
     89 #
     90 # 6. Removed x86_64-xlate.pl script (not needed for as(1) or gas(1) assemblers).
     91 #
     92 # 7. Removed unused RC4_CHAR, Lcloop1, and Lcloop8 code.
     93 #
     94 # 8. Added C function definitions for use by lint(1B).
     95 #
     96 
     97 use strict;
     98 my ($code, $dat, $inp, $out, $len, $idx, $ido, $i, @XX, @TX, $YY, $TY);
     99 my $output = shift;
    100 open STDOUT,">$output";
    101 
    102 #
    103 # Parameters
    104 #
    105 
    106 # OpenSSL:
    107 # void RC4(RC4_KEY *key, unsigned long len, const unsigned char *indata,
    108 #	unsigned char *outdata);
    109 #$dat="%rdi";	    # arg1
    110 #$len="%rsi";	    # arg2
    111 #$inp="%rdx";	    # arg3
    112 #$out="%rcx";	    # arg4
    113 
    114 # OpenSolaris:
    115 # void arcfour_crypt_asm(ARCFour_key *key, uchar_t *in, uchar_t *out,
    116 #	size_t len);
    117 $dat="%rdi";	    # arg1
    118 $inp="%rsi";	    # arg2
    119 $out="%rdx";	    # arg3
    120 $len="%rcx";	    # arg4
    121 
    122 #
    123 # Register variables
    124 #
    125 # $XX[0] is key->i (aka key->x), $XX[1] is a temporary.
    126 # $TX[0] and $TX[1] are temporaries.
    127 # $YY is key->j (aka key->y).
    128 # $TY is a temporary.
    129 #
    130 @XX=("%r8","%r10");
    131 @TX=("%r9","%r11");
    132 $YY="%r12";
    133 $TY="%r13";
    134 
    135 $code=<<___;
    136 #if defined(lint) || defined(__lint)
    137 
    138 #include "arcfour.h"
    139 
    140 /* ARGSUSED */
    141 void
    142 arcfour_crypt_asm(ARCFour_key *key, uchar_t *in, uchar_t *out, size_t len)
    143 {}
    144 
    145 /* ARGSUSED */
    146 void
    147 arcfour_key_init(ARCFour_key *key, uchar_t *keyval, int keyvallen)
    148 {}
    149 
    150 #else
    151 #include <sys/asm_linkage.h>
    152 
    153 ENTRY_NP(arcfour_crypt_asm)
    154 	/* EXPORT DELETE START */
    155 
    156 	or	$len,$len # If (len == 0) return
    157 	jne	.Lentry
    158 	ret
    159 .Lentry:
    160 	push	%r12
    161 	push	%r13
    162 
    163 	/ Set $dat to beginning of array, key->arr[0]
    164 	add	\$8,$dat
    165 	/ Get key->j
    166 	movl	-8($dat),$XX[0]#d
    167 	/ Get key->i
    168 	movl	-4($dat),$YY#d
    169 
    170 	/
    171 	/ Use a 4-byte key schedule element array
    172 	/
    173 	inc	$XX[0]#b
    174 	movl	($dat,$XX[0],4),$TX[0]#d
    175 	test	\$-8,$len
    176 	jz	.Lloop1
    177 	jmp	.Lloop8
    178 
    179 .align	16
    180 .Lloop8:
    181 ___
    182 for ($i=0;$i<8;$i++) {
    183 $code.=<<___;
    184 	add	$TX[0]#b,$YY#b
    185 	mov	$XX[0],$XX[1]
    186 	movl	($dat,$YY,4),$TY#d
    187 	ror	\$8,%rax			# ror is redundant when $i=0
    188 	inc	$XX[1]#b
    189 	movl	($dat,$XX[1],4),$TX[1]#d
    190 	cmp	$XX[1],$YY
    191 	movl	$TX[0]#d,($dat,$YY,4)
    192 	cmove	$TX[0],$TX[1]
    193 	movl	$TY#d,($dat,$XX[0],4)
    194 	add	$TX[0]#b,$TY#b
    195 	movb	($dat,$TY,4),%al
    196 ___
    197 push(@TX,shift(@TX)); push(@XX,shift(@XX));	# "rotate" registers
    198 }
    199 $code.=<<___;
    200 	ror	\$8,%rax
    201 	sub	\$8,$len
    202 
    203 	xor	($inp),%rax
    204 	add	\$8,$inp
    205 	mov	%rax,($out)
    206 	add	\$8,$out
    207 
    208 	test	\$-8,$len
    209 	jnz	.Lloop8
    210 	cmp	\$0,$len
    211 	jne	.Lloop1
    212 
    213 .Lexit:
    214 	/
    215 	/ Cleanup and exit code
    216 	/
    217 	/ --i to undo ++i done at entry
    218 	sub	\$1,$XX[0]#b
    219 	/ set key->i
    220 	movl	$XX[0]#d,-8($dat)
    221 	/ set key->j
    222 	movl	$YY#d,-4($dat)
    223 
    224 	pop	%r13
    225 	pop	%r12
    226 	ret
    227 
    228 .align	16
    229 .Lloop1:
    230 	add	$TX[0]#b,$YY#b
    231 	movl	($dat,$YY,4),$TY#d
    232 	movl	$TX[0]#d,($dat,$YY,4)
    233 	movl	$TY#d,($dat,$XX[0],4)
    234 	add	$TY#b,$TX[0]#b
    235 	inc	$XX[0]#b
    236 	movl	($dat,$TX[0],4),$TY#d
    237 	movl	($dat,$XX[0],4),$TX[0]#d
    238 	xorb	($inp),$TY#b
    239 	inc	$inp
    240 	movb	$TY#b,($out)
    241 	inc	$out
    242 	dec	$len
    243 	jnz	.Lloop1
    244 	jmp	.Lexit
    245 
    246 	/* EXPORT DELETE END */
    247 	ret
    248 SET_SIZE(arcfour_crypt_asm)
    249 ___
    250 
    251 
    252 #
    253 # Parameters
    254 #
    255 
    256 # OpenSSL:
    257 # void RC4_set_key(RC4_KEY *key, int len, const unsigned char *data);
    258 #$dat="%rdi";	    # arg1
    259 #$len="%rsi";	    # arg2
    260 #$inp="%rdx";	    # arg3
    261 
    262 # OpenSolaris:
    263 # void arcfour_key_init(ARCFour_key *key, uchar_t *keyval, int keyvallen);
    264 $dat="%rdi";	    # arg1
    265 $inp="%rsi";	    # arg2
    266 $len="%rdx";	    # arg3
    267 
    268 # Temporaries
    269 $idx="%r8";
    270 $ido="%r9";
    271 
    272 $code.=<<___;
    273 	/ int arcfour_crypt_on_intel(void);
    274 .extern	arcfour_crypt_on_intel
    275 
    276 ENTRY_NP(arcfour_key_init)
    277 	/* EXPORT DELETE START */
    278 
    279 	/ Find out if we're running on Intel or something else (e.g., AMD64).
    280 	/ This sets %eax to 1 for Intel, otherwise 0.
    281 	push	%rdi		/ Save arg1
    282 	push	%rsi		/ Save arg2
    283 	push	%rdx		/ Save arg3
    284 	call	arcfour_crypt_on_intel
    285 	pop	%rdx		/ Restore arg3
    286 	pop	%rsi		/ Restore arg2
    287 	pop	%rdi		/ Restore arg1
    288 	/ Save return value in key->flag (1=Intel, 0=AMD)
    289 	movl	%eax,1032($dat)
    290 
    291 	/ Set $dat to beginning of array, key->arr[0]
    292 	lea	8($dat),$dat
    293 	lea	($inp,$len),$inp
    294 	neg	$len
    295 	mov	$len,%rcx
    296 
    297 	xor	%eax,%eax
    298 	xor	$ido,$ido
    299 	xor	%r10,%r10
    300 	xor	%r11,%r11
    301 
    302 	/ Use a 4-byte data array
    303 	jmp	.Lw1stloop
    304 
    305 .align	16
    306 .Lw1stloop:
    307 	/ AMD64 (4-byte array)
    308 	mov	%eax,($dat,%rax,4)
    309 	add	\$1,%al
    310 	jnc	.Lw1stloop
    311 
    312 	xor	$ido,$ido
    313 	xor	$idx,$idx
    314 
    315 .align	16
    316 .Lw2ndloop:
    317 	mov	($dat,$ido,4),%r10d
    318 	add	($inp,$len,1),$idx#b
    319 	add	%r10b,$idx#b
    320 	add	\$1,$len
    321 	mov	($dat,$idx,4),%r11d
    322 	cmovz	%rcx,$len
    323 	mov	%r10d,($dat,$idx,4)
    324 	mov	%r11d,($dat,$ido,4)
    325 	add	\$1,$ido#b
    326 	jnc	.Lw2ndloop
    327 
    328 	/ Exit code
    329 	xor	%eax,%eax
    330 	mov	%eax,-8($dat)
    331 	mov	%eax,-4($dat)
    332 
    333 	/* EXPORT DELETE END */
    334 	ret
    335 SET_SIZE(arcfour_key_init)
    336 .asciz	"RC4 for x86_64, CRYPTOGAMS by <appro\@openssl.org>"
    337 #endif /* !lint && !__lint */
    338 ___
    339 
    340 $code =~ s/#([bwd])/$1/gm;
    341 
    342 print $code;
    343 
    344 close STDOUT;
    345