On Mon 2022-11-14 17:35:32, John Ogness wrote: > When setting up the early console, the setup() callback of the > regular console is used. It is called manually before registering > the early console instead of providing a setup() callback for the > early console. This is probably because the early setup needs a > different @options during the early stage. > > The issue here is that the setup() callback is called without the > console_list_lock held and functions such as uart_set_options() > expect that. > > Rather than manually calling the setup() function before registering, > provide an early console setup() callback that will use the different > early options. This ensures that the error checking, ordering, and > locking context when setting up the early console are correct. > > Since this early console can only be registered via the earlyprintk= > parameter, the @options argument of the setup() callback will always > be NULL. Rather than simply ignoring the argument, add a WARN_ON() > to get our attention in case the setup() callback semantics should > change in the future. > > Note that technically the current implementation works because it is > only used in early boot. And since the early console setup is > performed before registering, it cannot race with anything and thus > does not need any locking. However, longterm maintenance is easier > when drivers rely on the subsystem API rather than manually > implementing steps that could cause breakage in the future. > > Signed-off-by: John Ogness <john.ogness@xxxxxxxxxxxxx> > Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> Reviewed-by: Petr Mladek <pmladek@xxxxxxxx> Best Regards, Petr
