linux-kernel - Re: [RFC PATCH 3/4] ARM: l2x0: add arm,ecc-enable property for aurora

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 09 Jun 2017 10:58:12 +0200
From:   Jan Lübbe <jlu@...gutronix.de>
To:     Chris Packham <chris.packham@...iedtelesis.co.nz>
Cc:     bp@...en8.de, linux-arm-kernel@...ts.infradead.org,
        linux-edac@...r.kernel.org, Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Russell King <linux@...linux.org.uk>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 3/4] ARM: l2x0: add arm,ecc-enable property for
 aurora

On Do, 2017-06-08 at 16:11 +1200, Chris Packham wrote:
> +       if (of_property_read_bool(np, "arm,ecc-enable")) {
> +               mask |= L2C_AUX_CTRL_EVTMON_ENABLE;
> +               val |= L2C_AUX_CTRL_EVTMON_ENABLE;
> +       } else if (of_property_read_bool(np, "arm,ecc-disable")) {
> +               mask |= L2C_AUX_CTRL_EVTMON_ENABLE;
> +       }

Unless I misunderstand the code in __l2c_init(), the mask is used to
specify the bits to preserve:
        old_aux = aux = readl_relaxed(l2x0_base + L2X0_AUX_CTRL);
        aux &= aux_mask;
        aux |= aux_val;

        if (old_aux != aux)
                pr_warn("L2C: DT/platform modifies aux control register: 0x%08x -> 0x%08x\n",
                        old_aux, aux);

So the arm,ecc-disable property will have no effect. This probably also
applies to patch 2/4. The existing property *-disable code removes the
corresponding bit from the mask.

Regards,
Jan
-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |