From: Paul Burton <paul.burton@mips.com>
To: Paul Burton <pburton@wavecomp.com>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>,
"David S. Miller" <davem@davemloft.net>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
Paul Burton <pburton@wavecomp.com>,
Serge Semin <Sergey.Semin@t-platforms.ru>,
"linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>
Subject: Re: [PATCH] FDDI: defza: Include linux/io-64-nonatomic-lo-hi.h
Date: Mon, 24 Jun 2019 21:16:08 +0000 [thread overview]
Message-ID: <MWHPR2201MB1277792136FAB29E384E2152C1E00@MWHPR2201MB1277.namprd22.prod.outlook.com> (raw)
In-Reply-To: <20190620221224.27352-1-paul.burton@mips.com>
Hello,
Paul Burton wrote:
> Currently arch/mips/include/asm/io.h provides 64b memory accessor
> functions such as readq & writeq even on MIPS32 platforms where those
> accessors cannot actually perform a 64b memory access. They instead
> BUG(). This is unfortunate for drivers which either #ifdef on the
> presence of these accessors, or can function with non-atomic
> implementations of them found in either linux/io-64-nonatomic-lo-hi.h or
> linux/io-64-nonatomic-hi-lo.h. As such we're preparing to remove the
> definitions of these 64b accessor functions for MIPS32 kernels.
>
> In preparation for this, include linux/io-64-nonatomic-lo-hi.h in
> defza.c in order to provide a non-atomic implementation of the
> readq_relaxed & writeq_relaxed functions that are used by this code. In
> practice this will have no runtime effect, since use of the 64b accessor
> functions is conditional upon sizeof(unsigned long) == 8, ie. upon
> CONFIG_64BIT=y. This means the calls to these non-atomic readq & writeq
> implementations will be optimized out anyway, but we need their
> definitions to keep the compiler happy.
>
> For 64bit kernels using this code this change should also have no effect
> because asm/io.h will continue to provide the definitions of
> readq_relaxed & writeq_relaxed, which linux/io-64-nonatomic-lo-hi.h
> checks for before defining itself.
>
> Signed-off-by: Paul Burton <paul.burton@mips.com>
> Cc: Serge Semin <Sergey.Semin@t-platforms.ru>
> Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: netdev@vger.kernel.org
> Cc: linux-mips@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Acked-by: Maciej W. Rozycki <macro@linux-mips.org>
> Acked-by: David S. Miller <davem@davemloft.net>
Applied to mips-next.
Thanks,
Paul
[ This message was auto-generated; if you believe anything is incorrect
then please email paul.burton@mips.com to report it. ]
prev parent reply other threads:[~2019-06-24 21:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-20 22:13 [PATCH] FDDI: defza: Include linux/io-64-nonatomic-lo-hi.h Paul Burton
2019-06-21 2:09 ` Maciej W. Rozycki
2019-06-23 18:25 ` David Miller
2019-06-24 21:16 ` Paul Burton [this message]
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