Versatile Express randomly fails to boot

[Russell King - ARM Linux]

On Mon, Mar 16, 2015 at 12:04:38AM +0000, Russell King - ARM Linux wrote:
> On Sun, Mar 15, 2015 at 09:33:30PM +0000, Russell King - ARM Linux wrote:
> > I'm going to try a few other kernels to try and track down what's going
> > on - whether something from arm-soc or my tree is responsible for this
> > really weird behaviour.
> 
> Okay, this is weird - it seems that it's caused by the FIQ oops
> dumping code/FIQ changes which I've carried for many months
> unchanged in my tree.

More weirdness.  Progressing forwards through my development code
showed that when I merged the patch I mentioned in the previous mail,
things started to fail.

As I also mentioned, I'd drop that branch (two patches, one adding
the IPI backtrace stuff and the second one updating the GIC to allow
it to raise FIQs on suitably equipped platforms.)  I would have
expected that to have worked, but it just failed after four boot
iterations.  So either it's not the FIQ, or it is the FIQ code _and_
also something else.  Or it has something to do with the placement
of functions in the kernel.

I'll try more stuff tomorrow, working from where I presently am
(which is basically last night's code minus the FIQ changes) by
removing other changes to see what brings us back to a working
system.

As I've already said - this is really weird because all of these
changes were also tested against -rc1... those which weren't are:

mm: fold arch_randomize_brk into ARCH_HAS_ELF_RANDOMIZE
mm: split ET_DYN ASLR from mmap ASLR
mm: move randomize_et_dyn into ELF_ET_DYN_BASE
mm: expose arch_mmap_rnd when available
arm: factor out mmap ASLR into mmap_rnd

and a number of clkdev rework patches (to make it use clk_hw
internally.)  Neither of these should be affecting it, but that's
something I will be testing tomorrow.

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