linux-kernel - Re: [PATCH] arm: l2c: unlock ways when in non-secure mode

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Message-ID: <20171127091937.GA31757@n2100.armlinux.org.uk>
Date:   Mon, 27 Nov 2017 09:19:38 +0000
From:   Russell King - ARM Linux <linux@...linux.org.uk>
To:     Peng Fan <peng.fan@....com>
Cc:     "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "van.freenix@...il.com" <van.freenix@...il.com>,
        Mark Rutland <mark.rutland@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Chris Brandt <chris.brandt@...esas.com>,
        Will Deacon <will.deacon@....com>
Subject: Re: [PATCH] arm: l2c: unlock ways when in non-secure mode

On Sun, Nov 26, 2017 at 11:56:10PM +0000, Peng Fan wrote:
> Hi Russell,
> 
> > Subject: Re: [PATCH] arm: l2c: unlock ways when in non-secure mode
> > 
> > On Sun, Nov 26, 2017 at 08:25:30PM +0800, Peng Fan wrote:
> > > To boot Linux in Non-secure mode with l2x0, the l2x0 controller is
> > > enabled in secure mode and ways locked to make it seems L2 cache
> > > disabled during linux boot process. So during l2x0 initialization,
> > > need to unlock the ways to make l2x0 could cache data/inst.
> > 
> > Why was this chosen instead of doing what everyone else does?
> 
> I am not aware of how other platform handles the l2x0 unlock in non
> secure mode. Could you please share with me what others choose?

That's not what I was asking.

Everyone else provides a way for the l2x0 controller to be enabled and
disabled from non-secure mode.

Why have you decided to enable the l2x0 controller and leave it enabled,
and then lock down all the cache ways - which means you need the kernel
to do something entirely different for your platform.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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