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From: Benjamin Herrenschmidt <benh@kernel•crashing.org>
To: Roland McGrath <roland@redhat•com>
Cc: linuxppc-dev@ozlabs•org
Subject: Re: how to check for "optional" ppc chip features (MSR_BE)
Date: Mon, 05 May 2008 07:45:49 +1000	[thread overview]
Message-ID: <1209937549.21644.2.camel@pasglop> (raw)
In-Reply-To: <DC173CDE-FBC4-4EA0-8022-3F993B6466BF@kernel.crashing.org>


On Thu, 2008-05-01 at 22:48 -0500, Kumar Gala wrote:
> 
> Look at arch/powerpc/kernel/cputable.c to see how we handle issues  
> like this.
> 

Oh and classic pitfall: If you define a new feature bit, make sure
CPU_FTRS_POSSIBLE is updated to contain it in cputable.h

Also, It may not be totally clear, but:

PPC_FEATURE_* are exposed to userspace via AT_HWCAP

CPU_FTR_* are kernel internal (and can be used for runtime patching of
assembly code).

Ben.

  reply	other threads:[~2008-05-04 21:45 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-05-02  1:21 how to check for "optional" ppc chip features (MSR_BE) Roland McGrath
2008-05-02  3:48 ` Kumar Gala
2008-05-04 21:45   ` Benjamin Herrenschmidt [this message]
2008-05-04 23:12     ` Roland McGrath
2008-05-05  0:49       ` Benjamin Herrenschmidt
2008-05-13 11:55       ` Paul Mackerras
2008-05-13 13:47         ` Kumar Gala
2008-05-13 19:33         ` Roland McGrath
2008-06-11 16:05           ` Kumar Gala

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