ARM errata 430973 on multi platform kernels

[Tony Lindgren]

* Ivaylo Dimitrov <ivo.g.dimitrov.75 at gmail.com> [150403 15:08]:
> Hi
> 
> On  3.04.2015 19:35, Sebastian Reichel wrote:
> >
> >Maybe an option would be to provide two cpu_v7_switch_mm
> >implementations (one with the errata and one without). Then
> >the system can start with the simple implementation. Once
> >the boot as progressed far enough to know, that the hardware
> >is affected by the errata, it could switch to the implementation
> >with the flushing.
> 
> Or rather the opposite, as if the kernel itself is thumb-compiled, it most
> probably will have no chance to progress enough to switch to the correct
> implementation before hanging.

We should first verify the same bug happens with armel also.
I just verified the CPU load in the background makes armhf
apps segfault without $subject workaround enabled.

If the segfaulting does not happen with armel, then chances
it's some kind of neon related issue and the fix can be more
targeted.

Regards,

Tony