Building of arch/arm/plat-mxc/ssi-fiq.S failed w/ THUMB2 enabled?

On Fri, Jan 20, 2012 at 11:56:06AM +0000, Russell King - ARM Linux wrote:

On Fri, Dec 02, 2011 at 01:39:11PM +0000, Dave Martin wrote:

quoted

Is this code still used on ARMv7 and above?  FIQ is not normally
available for Linux interrupts on hardware which makes use of the
TrustZone security extensions.  Plus, on modern hardware with a deep
memory hierarchy, FIQ is may not be all that "fast" either, due to
cache/TLB effects.

It's worth pointing out that people end up using FIQs for certain things
because the hardware requires you to do it.  So if a platform is using
them, they're probably not doing it out of choice, but are doing it
because it's a baseline requirement to get something working.

Agreed -- but I'm wondering whether this code is actually non-relevant
to newer platforms, and is only being built at all because of a
non-relevant driver being included in mx5_defconfig, or due to some
Kconfig anomaly.


If this is really non-relevant to any >= v7 platform, we just need
for fix Kconfig : this code should never ever be built into a Thumb-2
kernel in that case.


Unfotunately I don't have the i.MX hardware knowledge to answer that
"if" though... it's just a hunch on my part.

One of the i.MX guys will have to comment on that.

Cheers
---Dave