Re: [PATCH v3 0/2] arm64: Fix pending single-step debugging issues
From: Will Deacon
Date: Fri Jul 08 2022 - 12:31:48 EST
On Fri, Jul 01, 2022 at 03:14:16PM -0700, Doug Anderson wrote:
> On Tue, May 10, 2022 at 11:05 PM Sumit Garg <sumit.garg@xxxxxxxxxx> wrote:
> > This patch-set reworks pending fixes from Wei's series  to make
> > single-step debugging via kgdb/kdb on arm64 work as expected. There was
> > a prior discussion on ML  regarding if we should keep the interrupts
> > enabled during single-stepping. So patch #1 follows suggestion from Will
> >  to not disable interrupts during single stepping but rather skip
> > single stepping within interrupt handler.
> >  https://lore.kernel.org/all/20200509214159.19680-1-liwei391@xxxxxxxxxx/
> >  https://lore.kernel.org/all/CAD=FV=Voyfq3Qz0T3RY+aYWYJ0utdH=P_AweB=13rcV8GDBeyQ@xxxxxxxxxxxxxx/
> >  https://lore.kernel.org/all/20200626095551.GA9312@willie-the-truck/
> > Changes in v3:
> > - Reword commit descriptions as per Daniel's suggestions.
> > Changes in v2:
> > - Replace patch #1 to rather follow Will's suggestion.
> > Sumit Garg (2):
> > arm64: entry: Skip single stepping into interrupt handlers
> > arm64: kgdb: Set PSTATE.SS to 1 to re-enable single-step
> > arch/arm64/include/asm/debug-monitors.h | 1 +
> > arch/arm64/kernel/debug-monitors.c | 5 +++++
> > arch/arm64/kernel/entry-common.c | 18 +++++++++++++++++-
> > arch/arm64/kernel/kgdb.c | 2 ++
> > 4 files changed, 25 insertions(+), 1 deletion(-)
> Sorry it took so long for me to respond. I kept dreaming that I'd find
> the time to really dig deep into this to understand it fully and I'm
> finally giving up on it. I'm going to hope that Will and/or Catalin
> knows this area of the code well and can give it a good review. If not
> then I'll strive harder to make the time...
So the good news is that I spent a couple of days on this last week.
The bad news is that I'm nowhere done and about to disappear on holiday
for a week!
But anyway, I might be able to give this a review when I'm back. Failing
that, I wonder if enough of us have a little bit of time each that we
could hack on an agreed design together which covers the debug exception
behaviour beyond kgdb?