Re: [PATCH v2 0/9] s390: Improve this_cpu operations

Heiko Carstens
2026-03-20T11:39:22Z

On Thu, Mar 19, 2026 at 02:56:12PM +0100, Peter Zijlstra wrote:
> On Thu, Mar 19, 2026 at 01:04:54PM +0100, Heiko Carstens wrote:
> > v2:
> >
> > - Add proper PERCPU_PTR cast to most patches to avoid tons of sparse
> > warnings
> >
> > - Add missing __packed attribute to insn structure [Sashiko [2]]
> >
> > - Fix inverted if condition [Sashiko [2]]
> >
> > - Add missing user_mode() check [Sashiko [2]]
> >
> > - Move percpu_entry() call in front of irqentry_enter() call in all
> > entry paths to avoid that potential this_cpu() operations overwrite
> > the not-yet saved percpu code section indicator [Sashiko [2]]
>
> Would it make sense to add arch hooks to irqentry_{enter,exit}() ?

I guess it would make sense to have some architecture hook which
allows to run code on all entry/exit paths instead of duplicating the
code n times.

But apparently my code seems to have more bugs (e.g. I didn't consider
kprobes which would make the instruction comparison not work). So this
has to wait until I'm back after vacation.