Removal of NWFPE in its entirety, and VFP emulation code

[Nicolas Pitre]

On Wed, 10 Apr 2013, Russell King - ARM Linux wrote:

> On Wed, Apr 10, 2013 at 10:00:52PM +0300, Aaro Koskinen wrote:
> > Menuconfig mentions under "Floating point emulation" that "At least one
> > emulation must be selected". But if I compile my OS with EABI userspace
> > soft-float I guess I won't actually need to select any emulation,
> > or have I missed something? (I just checked my configs, and at least
> > on Kirkwood/openrd I have been already running without any emulation,
> > so I guess the help text is wrong?)
> 
> Well, it's that way to stop us being flooded with "why does my kernel
> stop after mounting the rootfs" questions.  Maybe that can be changed
> now, it depends whether we're absolutely certain that there's no FPA
> instructions in any binary being run on EABI-only userspaces.

It is at least clear according to the EABI documentation. The double 
float word ordering is also defined to be different from FPA's, making 
EABI and FPA incompatible.

> Given that such instructions will still be emulated if they're
> encountered, I think we need to have another option to at least report
> an error via the kernel message log should a FPA instruction be trapped.

Agreed.


Nicolas