linux-kernel - Re: [PATCH] net: mdio-octeon: Fix pointer/integer casts

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Message-ID: <CAOesGMiCKYVjf+-uyU-NeFiXmsL_26OG9k5W7geCPY-aAB-8ow@mail.gmail.com>
Date:   Tue, 12 Nov 2019 11:51:29 -0800
From:   Olof Johansson <olof@...om.net>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     David Miller <davem@...hat.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Network Development <netdev@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] net: mdio-octeon: Fix pointer/integer casts

On Tue, Nov 12, 2019 at 5:23 AM Andrew Lunn <andrew@...n.ch> wrote:
>
> On Mon, Nov 11, 2019 at 09:46:58PM -0800, David Miller wrote:
> > From: Olof Johansson <olof@...om.net>
> > Date: Sun, 10 Nov 2019 16:42:11 -0800
> >
> > > -static inline void oct_mdio_writeq(u64 val, u64 addr)
> > > +static inline void oct_mdio_writeq(u64 val, void __iomem *addr)
> > >  {
> > > -   cvmx_write_csr(addr, val);
> > > +   cvmx_write_csr((u64)addr, val);
> > >  }
> >
> > I hate stuff like this, I think you really need to fix this from the bottom
> > up or similar.  MMIO and such addresses are __iomem pointers, period.
>
> Yes, i agree, but did not want to push the work to Olof. The point of
> COMPILE_TEST is to find issues like this, code which should be
> architecture independent, but is not. The cast just papers over the
> cracks.
>
> At a minimum, could we fix the stub cvmx_write_csr() used for
> everything !MIPS. That should hopefully fix everything !MIPS, but
> cause MIPS to start issuing warning. The MIPS folks can then cleanup
> their code, which is really what is broken here.

I'm not disagreeing with Dave, going all the way down the rabbit hole
is preferred. In this case I mostly pushed the lack of __iomem usage
down one layer but not the whole way.

I'm unlikely to find time to do it in the near future myself (this was
a bit of a weekend drive-by from my side), but I don't mind doing it.
If someone else beats me to it, feel free to take it over.


-Olof