Hi Uros,
Any benchmarks for this? Seems like it's all in initialization code,
right? I'm CC'ing Andy into this.
Jason
On Thu, Aug 27, 2020 at 07:38:31PM +0200, Uros Bizjak wrote:
> x86_64 zero extends 32bit operations, so for 64bit operands,
> XORL r32,r32 is functionally equal to XORQ r64,r64, but avoids
> a REX prefix byte when legacy registers are used.
>
> Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx>
> Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> ---
> arch/x86/crypto/poly1305-x86_64-cryptogams.pl | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/crypto/poly1305-x86_64-cryptogams.pl b/arch/x86/crypto/poly1305-x86_64-cryptogams.pl
> index 137edcf038cb..7d568012cc15 100644
> --- a/arch/x86/crypto/poly1305-x86_64-cryptogams.pl
> +++ b/arch/x86/crypto/poly1305-x86_64-cryptogams.pl
> @@ -246,7 +246,7 @@ $code.=<<___ if (!$kernel);
> ___
> &declare_function("poly1305_init_x86_64", 32, 3);
> $code.=<<___;
> - xor %rax,%rax
> + xor %eax,%eax
> mov %rax,0($ctx) # initialize hash value
> mov %rax,8($ctx)
> mov %rax,16($ctx)
> @@ -2853,7 +2853,7 @@ $code.=<<___;
> .type poly1305_init_base2_44,\@function,3
> .align 32
> poly1305_init_base2_44:
> - xor %rax,%rax
> + xor %eax,%eax
> mov %rax,0($ctx) # initialize hash value
> mov %rax,8($ctx)
> mov %rax,16($ctx)
> @@ -3947,7 +3947,7 @@ xor128_decrypt_n_pad:
> mov \$16,$len
> sub %r10,$len
> xor %eax,%eax
> - xor %r11,%r11
> + xor %r11d,%r11d
> .Loop_dec_byte:
> mov ($inp,$otp),%r11b
> mov ($otp),%al
> @@ -4085,7 +4085,7 @@ avx_handler:
> .long 0xa548f3fc # cld; rep movsq
>
> mov $disp,%rsi
> - xor %rcx,%rcx # arg1, UNW_FLAG_NHANDLER
> + xor %ecx,%ecx # arg1, UNW_FLAG_NHANDLER
> mov 8(%rsi),%rdx # arg2, disp->ImageBase
> mov 0(%rsi),%r8 # arg3, disp->ControlPc
> mov 16(%rsi),%r9 # arg4, disp->FunctionEntry
> --
> 2.26.2
>
--
Jason A. Donenfeld
Deep Space Explorer
fr: +33 6 51 90 82 66
us: +1 513 476 1200
www.jasondonenfeld.com
www.zx2c4.com
zx2c4.com/keys/AB9942E6D4A4CFC3412620A749FC7012A5DE03AE.asc
