[RFC v7 07/21] um: extend arch_switch_to for alternate SUBARCH

[Johannes Berg]

On Tue, 2020-10-06 at 18:44 +0900, Hajime Tazaki wrote:
> This commit introduces additional argument of previous task when
> context switch happens.  New SUBARCH can use the new information to
> switch tasks in a subarch-specific manner.
> 
> The patch is particularly required by nommu mode implemented as a
> SUBARCH of UML.

Would probably be good to already say why here?

johannes