[fedora-arm] ARMv7 rootfs/repository?

[Gordan Bobic]

Chris Tyler wrote:
> On Wed, 2010-12-22 at 08:01 -0800, Andrew Burgess wrote:
>> On 12/22/2010 06:30:13 AM, Chris Tyler wrote:
>>
>>> There is an expected performance gain with the switch to hardfp, but
>>> that's a big challenge: you can't mix softfp and hardfp, so switching  
>>> to
>>> hardfp is like bootstrapping an entirely new architecture.
>> Since fedora has no problem mixing 32 and 64 bit executables it
>> seems like there's alot of infrastructure already done for this.
>> Just saying...
> 
> It's not a Fedora infrastructure issue, the ABIs are incompatible. I
> wish you could mix'n'match but that doesn't look possible.

What about kernel level FPU emulation? Is there such a thing? I could 
have sworn there used to be something that could be used as such. And it 
might be possible to make it quite transparent if it isn't required (so 
you can always have it in the kernel). Have the kernel trap the 
exception on the missing FPU instructions, save state, and then pass the 
to an emulation library. When that returns, restore state and resume.

It would mean much slower performance than softfp on FPU-less hardware, 
but it would allow for a transitional period where only VFP distro needs 
to be maintained, which still works (albeit slowly) on a non-VFP processor.

Then again, I'm not volunteering to add such a feature to the Linux 
kernel. :)

Gordan