Re: [PATCH] consolidate do_bug_frame() / bug_fn_t

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Answering out of order:

On 25/01/2024 8:15 am, Jan Beulich wrote:
> All fine. Still I wonder whether in the meantime this patch isn't an
> improvement on its own, and hence whether the const couldn't sensibly
> be added subsequently.

We have a while until 4.19 goes out.  I would prefer to try and get this
untangled properly, because half of your patch is in the opposite
direction for getting the const-ness working.

If we start to hit rc1 and the const-ness isn't complete, we can revisit.


Regarding the removal of gdb-stub.  I'd like to get that done, and
rebase the remainder of the IRQ series over it, because it will reduce
the churn in your IRQ series.  I'm happy to do the rebase if you want.


> On 25.01.2024 02:14, Andrew Cooper wrote:
>> To make the serial code compile, I ended up having to revert patch 2 of
>> the regs series, which I believe is safe to do following patch 3-5 which
>> un-plumb the regs pointer deeper in the call chain.  If this is turns
>> out to be true, then the patch ought to be added and reverted in the
>> same series so it isn't left hanging about after the fact.
> Hmm, I'm not sure I see how reverting that would end up working. However,
> aiui you need to revert primarily for the non-const-ness of the pointers
> involved in [gs]et_irq_regs(). I wonder whether, if we followed your
> underlying thought here, those shouldn't be const-ified then anyway.
>
>> The _$X_poll() functions are used in timer context, which means there's
>> an outer regs context already latched, and that's arguably a better
>> context to use anyway for 'd'.
> If the timer happens to run on an idle vCPU, what "outer regs context"
> would we have there?

The only reason the serial infrastructure was setting up a fake IRQ
context was because it was using run_in_exception_handler().

But I (think I have) removed that fully (and it simplifies things more
than I was hoping).

With '%' deleted, it's only 'd' that cares, isn't it?  And that's "dump
the current regs", rather than wanting something else.

~Andrew