linux-kernel - Re: [PATCH] arm32: fix flushcache syscall with device address

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Message-ID: <20200421165515.GF25745@shell.armlinux.org.uk>
Date:   Tue, 21 Apr 2020 17:55:16 +0100
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     James Morse <james.morse@....com>
Cc:     Jonathan Cameron <Jonathan.Cameron@...wei.com>, info@...ux.net,
        catalin.marinas@....com, linux-kernel@...r.kernel.org,
        linuxarm@...wei.com, allison@...utok.net,
        gregkh@...uxfoundation.org, Tian Tao <tiantao6@...ilicon.com>,
        tglx@...utronix.de, Will Deacon <will@...nel.org>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] arm32: fix flushcache syscall with device address

On Tue, Apr 21, 2020 at 05:50:22PM +0100, James Morse wrote:
> Hi guys,
> 
> (Subject Nit: arm64, as that is what your patch modifies)

That is irrelevent.  This is a compatibility interface which is supposed
to reflect the arm32 implementation.  Augmenting a compatibility
interface to do more than what it's counterpart that it's supposed to
be compatible with is senseless.

The API concerned is an ARM32 API which is expected to only be used
for ensuring I/D cache coherency, it is not for DMA.

Augmenting it on ARM64 for DMA is senseless.

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