VFP handling in multiplatform feroceon kernels

Catalin Marinas catalin.marinas at arm.com
Tue Jun 24 06:42:49 PDT 2014


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



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