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From: Ard Biesheuvel <ardb@kernel.org>
To: Stefan Kanthak <stefan.kanthak@nexgo.de>
Cc: linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org,
	 tim.c.chen@linux.intel.com, Eric Biggers <ebiggers@kernel.org>
Subject: Re: [PATCH v2 1/2] crypto: s(h)aving 16 byte constant off arch/x86/crypto/sha1_ni_asm.S
Date: Mon, 8 Apr 2024 16:37:22 +0200	[thread overview]
Message-ID: <CAMj1kXGTrx_9igrewHOkfHAej4NdJBSKHtpCoQcif08EtF0pAA@mail.gmail.com> (raw)
In-Reply-To: <20240408141817.E22F8128369@smtp.subspace.kernel.org>

On Mon, 8 Apr 2024 at 16:18, Stefan Kanthak <stefan.kanthak@nexgo.de> wrote:
>
> Get rid of 16 byte constant, use shift instead of mask
>

This is missing a signoff

> --- -/arch/x86/crypto/sha1_ni_asm.S
> +++ +/arch/x86/crypto/sha1_ni_asm.S
> @@ -104,9 +104,9 @@
>         add             DATA_PTR, NUM_BLKS      /* pointer to end of data */
>
>         /* load initial hash values */
> -       pinsrd          $3, 1*16(DIGEST_PTR), E0
> +       pinsrd          $0, 1*16(DIGEST_PTR), E0
>         movdqu          0*16(DIGEST_PTR), ABCD
> -       pand            UPPER_WORD_MASK(%rip), E0
> +       pslldq          $12, E0
>         pshufd          $0x1B, ABCD, ABCD
>

Wouldn't it be simpler and therefore better to simply zero register E0
before loading E into the top lane?


>         movdqa          PSHUFFLE_BYTE_FLIP_MASK(%rip), SHUF_MASK
> @@ -297,8 +297,3 @@
>  .align 16
>  PSHUFFLE_BYTE_FLIP_MASK:
>         .octa 0x000102030405060708090a0b0c0d0e0f
> -
> -.section       .rodata.cst16.UPPER_WORD_MASK, "aM", @progbits, 16
> -.align 16
> -UPPER_WORD_MASK:
> -       .octa 0xFFFFFFFF000000000000000000000000
>

       reply	other threads:[~2024-04-08 14:37 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20240408141817.E22F8128369@smtp.subspace.kernel.org>
2024-04-08 14:37 ` Ard Biesheuvel [this message]
2024-04-08 14:08 [PATCH v2 1/2] crypto: s(h)aving 16 byte constant off arch/x86/crypto/sha1_ni_asm.S Stefan Kanthak
  -- strict thread matches above, loose matches on Subject: below --
2024-04-08 14:08 Stefan Kanthak

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