Re: [PATCH 3/3] m68k: allow kexec on all MMU enabled CPUs

Geert Uytterhoeven
2022-08-30T07:36:20Z

Hi Greg,

On Tue, Aug 30, 2022 at 9:23 AM Greg Ungerer <gerg@linux-m68k.org> wrote:
> On 26/8/22 17:44, Geert Uytterhoeven wrote:
> > On Fri, Aug 26, 2022 at 6:08 AM Greg Ungerer <gerg@linux-m68k.org> wrote:
> >> The configuration setting for 68k kexec support limits it to only
> >> the classic 68k CPU types (so no ColdFire). However the underlying
> >> support can handle any 68k CPU that is MMU enabled - and that includes
> >> ColdFire. (Of course that support is only as good as mentioned in
> >> the current configuration help).
> >>
> >> None of the no-MMU CPU types (classic or ColdFire) have support for
> >> kexec yet, so the configuration as it stands is not quite right, and
> >> it will fail to compile on them.
> >>
> >> Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
> >
> >> --- a/arch/m68k/Kconfig
> >> +++ b/arch/m68k/Kconfig
> >> @@ -87,7 +87,7 @@ config MMU_SUN3
> >>
> >> config KEXEC
> >> bool "kexec system call"
> >> - depends on M68KCLASSIC
> >> + depends on MMU
> >> select KEXEC_CORE
> >> help
> >> kexec is a system call that implements the ability to shutdown your
> >
> > Don't you need changes to arch/m68k/kernel/relocate_kernel.S,
> > which supports 68020+ only?
>
> I suspect so looking at that now. It compiles ok, but without a
> check for MMU type specific to ColdFire it will likely fail.
> I didn't dig into it too deeply, my primary goal with to fix compilation
> for the non-MMU targets.
>
> I started out testing it with this:
>
> depends on M68KCLASSIC && MMU
>
> And that works and fixes the problem I was most interested in.
> But then I figured that perhaps it is better to allow if for ColdFire with MMU enabled.
>
> I didn't want to go down the rabbit hole of trying to get it working
> on non-MMU platforms (and ColdFire with MMU enabled either really).
>
> So I would be just as happy to limit it to M68KCLASSIC and MMU for now?

That sounds fine to me.
Thanks!