From: "Pali Rohár" <pali.rohar@gmail.com>
To: Sebastian Reichel <sre@kernel.org>
Cc: "Mark Rutland" <mark.rutland@arm.com>,
devicetree <devicetree@vger.kernel.org>,
"Paul Walmsley" <paul@pwsan.com>,
"Aaro Koskinen" <aaro.koskinen@iki.fi>,
"Tony Lindgren" <tony@atomide.com>,
"Adam Ford" <adam.ford@logicpd.com>,
"Russell King" <linux@armlinux.org.uk>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"Tero Kristo" <t-kristo@ti.com>,
"Rob Herring" <robh+dt@kernel.org>,
"Benoît Cousson" <bcousson@baylibre.com>,
Linux-OMAP <linux-omap@vger.kernel.org>,
"Adam Ford" <aford173@gmail.com>,
arm-soc <linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC] ARM: omap3: Enable HWMODS for HW Random Number Generator
Date: Tue, 10 Sep 2019 16:44:52 +0200 [thread overview]
Message-ID: <20190910144452.vmhmls3xhh6hd5xw@pali> (raw)
In-Reply-To: <20190910143732.3g3q4acvnx2pqvjx@earth.universe>
On Tuesday 10 September 2019 15:37:32 Sebastian Reichel wrote:
> Hi,
>
> On Tue, Sep 10, 2019 at 08:56:49AM -0500, Adam Ford wrote:
> > On Thu, Sep 5, 2019 at 6:04 PM Tony Lindgren <tony@atomide.com> wrote:
> > > Oh and this needs to default to status = "disabled" for
> > > HS devices like n900 as it needs to use the omap3-rom-rng.
> >
> > I don't know enough about the HS version of the OMAP3, but what's the
> > main difference between omap3-rom-rng and this one?
>
> The OMAP HS chips have the bus firewall configured to block direct
> access to some cryptography related devices. The kernel will crash
> with a bus error, if you try to read/write the registers for
> protected devices.
And if you try to read it more times, SOC would be rebooted for security
reasons.
> The omap3-rom-rng avoids this by communicating
> with the security middleware component instead of directly accessing
> the RNG hardware.
And that component is loaded by signed bootloader into "secure" area not
accessible by "non-secure" work (like kernel) and communication is done
via arm smc instruction.
--
Pali Rohár
pali.rohar@gmail.com
_______________________________________________
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prev parent reply other threads:[~2019-09-10 14:45 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-28 15:00 [RFC] ARM: omap3: Enable HWMODS for HW Random Number Generator Adam Ford
2019-09-05 23:04 ` Tony Lindgren
2019-09-09 12:13 ` Adam Ford
2019-09-09 13:37 ` Adam Ford
2019-09-09 13:40 ` Pali Rohár
2019-09-09 16:35 ` Tony Lindgren
2019-09-09 19:19 ` Adam Ford
2019-09-10 15:48 ` Adam Ford
2019-09-10 16:21 ` Adam Ford
2019-09-10 16:39 ` Pali Rohár
2019-10-22 12:13 ` Adam Ford
2019-10-22 16:06 ` Tony Lindgren
2019-09-10 13:56 ` Adam Ford
2019-09-10 14:37 ` Sebastian Reichel
2019-09-10 14:44 ` Pali Rohár [this message]
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