[PATCH] arm64: fix for bad_mode() handler to always result in panic

[will.deacon@arm.com (Will Deacon)]

Hi Hari,

Sorry, this has slipped through the cracks.

On Tue, Aug 21, 2018 at 07:46:04PM +0530, Hari Vyas wrote:
> On Fri, Aug 10, 2018 at 10:16 PM, Hari Vyas <hari.vyas@broadcom.com> wrote:
> > As far as I know, bad mode was earlier(linux 3.14 onwards) also not
> > resulting in panic always.
> > Trap-exception framework is recently changed some time back but this
> > concern remains same.
> > I am also awaiting a response from ARM maintainers before proceeding.
> > Just to be more clear, this
> > concern was pointed out in one of my previous-and-some-what-relative
> > patch about console-verbose
> > level restoration issue.
> >> Florian
> Gentle reminder for Arm maintainers.
> If concern can be taken care from your side in different ways then bug
> can be resolved.

I've recently started trying to untangle much of our fatal trap handling
code so that the decision between user-mode and kernel-mode actions is
explicit in the caller, rather than buried deep in the bowels of some
callchain. The aim is also to remove arm64_notify_die() entirely, which
is a complete maze of crap that ultimately depends on what kgdb does in
some cases!

With that out of the way, die() itself could probably be simplified so that
it (a) avoids the notifier chain [which is useless for us] and (b) is only
intended to be called for kernel contexts, i.e. as a wrapper around a
panic_on_oops check.

But this needn't affect your patch, which seems to be a small step in the
right direction. I'll pick it up as part of my series when I send it out,
if that's alright with you? I don't think any of this is especially urgent.

Will