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From:   Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Date:   Tue, 17 Aug 2021 14:33:43 +0100
Message-ID: <CADVatmMZs0GXD8MEEVZGkj9BHtHY+FeWGhE2AuQ9US5E1HeYEQ@mail.gmail.com>
Subject: Re: build failure of mips decstation_r4k_defconfig with binutils-2_37
To:     Ralf Baechle <ralf@linux-mips.org>
Cc:     "Maciej W. Rozycki" <macro@linux-mips.org>,
        Paul Burton <paulburton@kernel.org>,
        James Hogan <jhogan@kernel.org>,
        linux-mips <linux-mips@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Stable <stable@vger.kernel.org>
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Hi Ralf,

On Tue, Aug 17, 2021 at 1:55 PM Ralf Baechle <ralf@linux-mips.org> wrote:
>
> On Tue, Aug 17, 2021 at 12:54:32PM +0100, Sudip Mukherjee wrote:
>
> > While I was testing v5.4.142-rc2 I noticed mips build of
> > decstation_r4k_defconfig fails with binutils-2_37. The error is:
> >
> > arch/mips/dec/prom/locore.S: Assembler messages:
> > arch/mips/dec/prom/locore.S:29: Error: opcode not supported on this
> > processor: r4600 (mips3) `rfe'
> >
> > I have also reported this at https://sourceware.org/bugzilla/show_bug.cgi?id=28241
>
> It would appear gas got more anal about ISA checking for the RFE instructions
> which did only exist in MIPS I and II; MIPS III and later use ERET for
> returning from an exception.
>
> The older gas I've got installed here happily accepts RFE in MIPS III/R4000
> mode:
>

<snip>

>
> It's easy to find arguments for why this gas change is the right thing to
> do - and not the right thing to do.
>
> It should be fixable by simply putting gas into mips1 mode.  Can you test
> below patch?

Tested on top of v5.4.142-rc2 and it builds again. Thanks for the
quick reply and the patch.


-- 
Regards
Sudip