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From:   Horia Geanta <horia.geanta@nxp.com>
To:     Iuliana Prodan <iuliana.prodan@nxp.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Aymen Sghaier <aymen.sghaier@nxp.com>
CC:     "David S. Miller" <davem@davemloft.net>,
        "linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        dl-linux-imx <linux-imx@nxp.com>
Subject: Re: [PATCH v3 08/14] crypto: caam - update rfc4106 sh desc to support
 zero length input
Thread-Topic: [PATCH v3 08/14] crypto: caam - update rfc4106 sh desc to
 support zero length input
Thread-Index: AQHVQvERbpsKgfpmokSM8mMCvyAc5g==
Date:   Fri, 26 Jul 2019 15:44:46 +0000
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References: <1564063106-9552-1-git-send-email-iuliana.prodan@nxp.com>
 <1564063106-9552-9-git-send-email-iuliana.prodan@nxp.com>
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On 7/25/2019 4:58 PM, Iuliana Prodan wrote:=0A=
> @@ -892,24 +895,26 @@ void cnstr_shdsc_rfc4106_encap(u32 * const desc, st=
ruct alginfo *cdata,=0A=
>  	append_math_sub_imm_u32(desc, VARSEQINLEN, REG3, IMM, ivsize);=0A=
>  	append_math_add(desc, VARSEQOUTLEN, ZERO, REG3, CAAM_CMD_SZ);=0A=
>  =0A=
> -	/* Read assoc data */=0A=
> -	append_seq_fifo_load(desc, 0, FIFOLD_CLASS_CLASS1 | FIFOLDST_VLF |=0A=
> -			     FIFOLD_TYPE_AAD | FIFOLD_TYPE_FLUSH1);=0A=
> +	/* Skip AAD */=0A=
> +	append_seq_fifo_store(desc, 0, FIFOST_TYPE_SKIP | FIFOLDST_VLF);=0A=
>  =0A=
> -	/* Skip IV */=0A=
> -	append_seq_fifo_load(desc, ivsize, FIFOLD_CLASS_SKIP);=0A=
> +	/* Read cryptlen and set this value into VARSEQOUTLEN */=0A=
> +	append_math_sub(desc, VARSEQOUTLEN, SEQINLEN, REG3, CAAM_CMD_SZ);=0A=
>  =0A=
> -	/* Will read cryptlen bytes */=0A=
> -	append_math_sub(desc, VARSEQINLEN, SEQINLEN, REG0, CAAM_CMD_SZ);=0A=
> +	/* If cryptlen is ZERO jump to AAD command */=0A=
> +	zero_cryptlen_jump_cmd =3D append_jump(desc, JUMP_TEST_ALL |=0A=
> +					    JUMP_COND_MATH_Z);=0A=
>  =0A=
>  	/* Workaround for erratum A-005473 (simultaneous SEQ FIFO skips) */=0A=
> -	append_seq_fifo_load(desc, 0, FIFOLD_CLASS_CLASS1 | FIFOLD_TYPE_MSG);=
=0A=
> +	append_seq_fifo_store(desc, 0, FIFOST_TYPE_MESSAGE_DATA);=0A=
>  =0A=
The workaround should be moved further down, just before the "Skip IV".=0A=
=0A=
By moving this instruction as far away as possible from=0A=
previous seq fifo store, the chances of DECO stalling are reduced.=0A=
=0A=
> -	/* Skip assoc data */=0A=
> -	append_seq_fifo_store(desc, 0, FIFOST_TYPE_SKIP | FIFOLDST_VLF);=0A=
> +	/* Read AAD data */=0A=
> +	append_seq_fifo_load(desc, 0, FIFOLD_CLASS_CLASS1 | FIFOLDST_VLF |=0A=
> +			     FIFOLD_TYPE_AAD | FIFOLD_TYPE_FLUSH1);=0A=
>  =0A=
> -	/* cryptlen =3D seqoutlen - assoclen */=0A=
> -	append_math_sub(desc, VARSEQOUTLEN, VARSEQINLEN, REG0, CAAM_CMD_SZ);=0A=
> +	/* Skip IV */=0A=
> +	append_seq_fifo_load(desc, ivsize, FIFOLD_CLASS_SKIP);=0A=
> +	append_math_add(desc, VARSEQINLEN, VARSEQOUTLEN, REG0, CAAM_CMD_SZ);=0A=
>  =0A=
>  	/* Write encrypted data */=0A=
>  	append_seq_fifo_store(desc, 0, FIFOST_TYPE_MESSAGE_DATA | FIFOLDST_VLF)=
;=0A=
> @@ -918,6 +923,18 @@ void cnstr_shdsc_rfc4106_encap(u32 * const desc, str=
uct alginfo *cdata,=0A=
>  	append_seq_fifo_load(desc, 0, FIFOLD_CLASS_CLASS1 | FIFOLDST_VLF |=0A=
>  			     FIFOLD_TYPE_MSG | FIFOLD_TYPE_LAST1);=0A=
>  =0A=
> +	/* Jump instructions to avoid double reading of AAD */=0A=
> +	skip_instructions =3D append_jump(desc, JUMP_TEST_ALL);=0A=
> +=0A=
> +	/* There is no input data, cryptlen =3D 0 */=0A=
> +	set_jump_tgt_here(desc, zero_cryptlen_jump_cmd);=0A=
> +=0A=
> +	/* Read AAD */=0A=
> +	append_seq_fifo_load(desc, 0, FIFOLD_CLASS_CLASS1 | FIFOLDST_VLF |=0A=
> +			     FIFOLD_TYPE_AAD | FIFOLD_TYPE_LAST1);=0A=
> +=0A=
> +	set_jump_tgt_here(desc, skip_instructions);=0A=
> +=0A=
>  	/* Write ICV */=0A=
>  	append_seq_store(desc, icvsize, LDST_CLASS_1_CCB |=0A=
>  			 LDST_SRCDST_BYTE_CONTEXT);=0A=