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

[Martin Schiller <ms@dev.tdt.de>]

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@dev.tdt.de>
>> ---
>>  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...