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From: catalin.marinas@arm.com (Catalin Marinas)
To: linux-arm-kernel@lists.infradead.org
Subject: VFP handling in multiplatform feroceon kernels
Date: Tue, 24 Jun 2014 14:42:49 +0100	[thread overview]
Message-ID: <20140624134249.GB4489@arm.com> (raw)
In-Reply-To: <7416978.W29blLsymn@wuerfel>

On Tue, Jun 24, 2014 at 02:17:06PM +0100, Arnd Bergmann wrote:
> Since 3.16, we have the ability to build a multiplatform kernel
> that includes both kirkwood (feroceon) and some other ARMv5 CPU.
> 
> I accidentally stumbled over a bug in the VFP code that looks
> like it will break at least ARM9 VFP support if CPU_FEROCEON
> is also enabled, introduced by this (old) commit:

I would argue that the bug is in the CPU (feroceon). See the end of this
email:

http://www.spinics.net/lists/arm-kernel/msg41460.html

and my follow-up. Basically you can't avoid the conditional compilation
as Feroceon doesn't follow the VFP sub-architecture spec and doesn't
present itself as a different CPU from an _ARM_ 9. Unless things have
changed with Marvell's hardware implementation and they got a new id, I
suggest you don't enable this for multi-platform.

-- 
Catalin

  parent reply	other threads:[~2014-06-24 13:42 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-24 13:17 VFP handling in multiplatform feroceon kernels Arnd Bergmann
2014-06-24 13:31 ` Andrew Lunn
2014-06-24 13:47   ` Arnd Bergmann
2014-06-24 13:42 ` Catalin Marinas [this message]
2014-06-24 13:57   ` Arnd Bergmann
2014-06-24 14:04   ` Nicolas Pitre
2014-06-24 14:10     ` Catalin Marinas
2014-06-24 14:14       ` Russell King - ARM Linux
2014-06-24 14:25         ` Catalin Marinas
2014-06-24 14:32           ` Arnd Bergmann
2014-06-24 14:45             ` Nicolas Pitre
2014-06-24 14:35           ` Russell King - ARM Linux
2014-06-24 14:56             ` Nicolas Pitre
2014-06-24 15:01               ` Arnd Bergmann
2014-06-24 14:49       ` Nicolas Pitre
2014-06-24 14:56         ` Arnd Bergmann
2014-06-24 14:08 ` Russell King - ARM Linux

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