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From:   Andrey Smirnov <andrew.smirnov@gmail.com>
Date:   Mon, 27 Jan 2020 05:45:42 -0800
Message-ID: <CAHQ1cqG185EmhTYGwfm4LBrhbX1ibACaTAjZ5UnZ5uYx+o88HQ@mail.gmail.com>
Subject: Re: [PATCH v6 6/7] crypto: caam - enable prediction resistance in HRWNG
To:     Horia Geanta <horia.geanta@nxp.com>
Cc:     "linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
        Chris Healy <cphealy@gmail.com>,
        Lucas Stach <l.stach@pengutronix.de>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Iuliana Prodan <iuliana.prodan@nxp.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        dl-linux-imx <linux-imx@nxp.com>
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On Wed, Jan 22, 2020 at 5:37 AM Horia Geanta <horia.geanta@nxp.com> wrote:
>
> On 1/21/2020 6:38 PM, Horia Geanta wrote:
> > On 1/8/2020 5:42 PM, Andrey Smirnov wrote:
> >> @@ -275,12 +276,25 @@ static int instantiate_rng(struct device *ctrldev, int state_handle_mask,
> >>              return -ENOMEM;
> >>
> >>      for (sh_idx = 0; sh_idx < RNG4_MAX_HANDLES; sh_idx++) {
> >> +            const u32 rdsta_if = RDSTA_IF0 << sh_idx;
> >> +            const u32 rdsta_pr = RDSTA_PR0 << sh_idx;
> >> +            const u32 rdsta_mask = rdsta_if | rdsta_pr;
> >>              /*
> >>               * If the corresponding bit is set, this state handle
> >>               * was initialized by somebody else, so it's left alone.
> >>               */
> >> -            if ((1 << sh_idx) & state_handle_mask)
> >> -                    continue;
> >> +            if (rdsta_if & state_handle_mask) {
> >> +                    if (rdsta_pr & state_handle_mask)
> > instantiate_rng() is called with
> >       state_handle_mask = rd_reg32(&ctrl->r4tst[0].rdsta) & RDSTA_IFMASK;
> > so if (rdsta_pr & state_handle_mask) will always be false,
> > leading to unneeded state handle re-initialization.
> >
> Sorry, I missed this change:
> -#define RDSTA_IFMASK (RDSTA_IF1 | RDSTA_IF0)
> +#define RDSTA_IFMASK (RDSTA_PR1 | RDSTA_PR0 | RDSTA_IF1 | RDSTA_IF0)
>
> which means code is correct (though I must admit not so intuitive).

Renamed this to RDSTA_MASK in v7, to, hopefully make things more clear.

Thanks,
Andrey Smirnov