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Re: [PATCH] MIPS: Tell R4k SC and MC variations apart

To: "Maciej W. Rozycki" <macro@linux-mips.org>
Subject: Re: [PATCH] MIPS: Tell R4k SC and MC variations apart
From: Ralf Baechle <ralf@linux-mips.org>
Date: Wed, 25 Sep 2013 13:02:31 +0200
Cc: linux-mips@linux-mips.org
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On Wed, Sep 25, 2013 at 12:37:42AM +0100, Maciej W. Rozycki wrote:

> > My reservations may have been about userland reading /proc/cpuinfo and
> > looking at the CPU type.  Some software may know how to handle the
> > PC/SC variants but not the MC versions.  But this seems to be a fairly
> > weak concern - and I trust you checked gcc's parsing of /proc/cpuinfo.
> 
>  Actually I wasn't actually aware GCC's got /proc/cpuinfo-based native 
> arch support for the MIPS target these days, thanks for the hint.
> 
>  I have now checked the relevant source file and support is pretty weak 
> there, only half a dozen processors are recognised and no R4k model is 
> among them.  In any case strstr is used to check for matches there so I'd 
> expect strings like "R4000" or "R4400" without a further suffix to be 
> chosen.

It'd be worth a change in particular for users how higher end CPUs and
enhanced ISAs such as Octeons.

Or should we just default to O32 w/ MIPS I + LL/SC as the MIPS Esperanto
forever ...

  Ralf

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