Re: [PATCH] x86/reboot: Add call to do_kernel_restart()

[Martin Schiller]

On 2026-02-25 06:32, Borislav Petkov wrote:
> On Fri, Feb 20, 2026 at 01:29:01PM +0100, Martin Schiller wrote:
> > SoC devices like the Intel / MaxLinear Lightning Mountain must be 
> > reset
> > by the RCU instead of using  "normal" x86 mechanisms like ACPI, BIOS,
>
> Read-Copy-Update?

Sorry, I forgot to explain the abbreviation.
RCU is short for Reset Control Unit. That's what it's called in the
Intel / MaxLinear world.

> I'm relatively sure you don't mean that.
>
> > KBD, etc.
> >
> > Therefore, the RCU driver (reset-intel-gw) registers a restart handler
> > which triggers the global reset signal.
> >
> > Unfortunately, this is of no use as long as the restart chain is not
> > processed during reboot on x86 systems.
> >
> > So we must call do_kernel_restart() when a reboot is performed. This 
> > has
>
> Who's "we"?

I don't mean anyone in particular. I just wanted to express that the
function must be called.

> > long been common practice for other architectures.
> >
> > Signed-off-by: Martin Schiller <ms@xxxxxxxxxx>
> > ---
> >  arch/x86/kernel/reboot.c | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
> > index 
> > 6032fa9ec753ce938b1b523a7eab76370ee802de..ddff25a1efbe71171ca22ec21f50541517c1a464 
> > 100644
> > --- a/arch/x86/kernel/reboot.c
> > +++ b/arch/x86/kernel/reboot.c
> > @@ -773,12 +773,15 @@ static void __machine_emergency_restart(int 
> > emergency)
> >  	machine_ops.emergency_restart();
> >  }
> >
> > -static void native_machine_restart(char *__unused)
> > +static void native_machine_restart(char *command)
> >  {
> >  	pr_notice("machine restart\n");
> >
> >  	if (!reboot_force)
> >  		machine_shutdown();
> > +
> > +	do_kernel_restart(command);
>
> I guess we can do that - the other arches do it already...