[PATCH 2/3] ARM: make disable_fiq macro optional

[Nicolas Pitre]

On Wed, 8 Feb 2012, Russell King - ARM Linux wrote:

> On Wed, Feb 08, 2012 at 01:58:37PM -0600, Rob Herring wrote:
> > Nico suggested adding a default handler with set_fiq_handler which would
> > do this same write to IOMD_FIQMASK. Or I can leave the ifdef for RPC
> > around disable_fiq. Guidance with what you would like to see here would
> > be helpful.
> 
> I don't think so - you either end up leaving a window where we disable
> FIQs in the CPSR (which could get propagated to other threads) or you
> leave a window where an errant FIQ could lock the system.

I was thinking about hooking a subarch specific disable_fiq handler 
using set_fiq_handler() from the mdesc->init_early callback.  This is 
done after the vector page is initialized, and if I'm not mistaken, IRQs 
and FIQs are still disabled at that point.


Nicolas