Re: earmv7hf panic

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Thu, Jul 18, 2019 at 10:55:30PM +0200, Manuel Bouyer wrote:
> [...]
> So:
> - we have VFP_FPEXC_EX in fregs->vfp_fpexc
> - we just wrote fregs->vfp_fpexc back to the fpexc register
> - reading back the fpexc register, VFP_FPEXC_EX is not set
> - also, the saved fpinst doens't looks like a valid FP instruction
> 
> from the armv7 manual, this is a reliable way to know that the
> fpinst is not implemented. We're probably faulting because we try
> to write an unimplemented register.
> 
> But how did we get VFP_FPEXC_EX set in the first place, if this bit is always
> 0 in the register ? This, and the saved fpinst value, makes me suspect that
> the saved state is corrupted or not properly initialized.

It turns out it is a stack overflow in sunxi_hdmi.c, corrupting proc0's pcb.
I just commited a fix.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
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