Commit 65e20e8c authored by Michael Walle's avatar Michael Walle Committed by Greg Kroah-Hartman
Browse files

earlycon: prevent multiple register_console() 



If the earlycon parameter is given twice, the kernel will spit out a
WARN() in register_console() because it was already registered. The
non-dt variant setup_earlycon() already handles that gracefully. The dt
variant of_setup_earlycon() doesn't. Add the check there and add the
-EALREADY handling in early_init_dt_scan_chosen_stdout().

FWIW, this doesn't happen if CONFIG_ACPI_SPCR_TABLE is set. In that case
the registration is delayed until after earlycon parameter(s) are
parsed.

Reviewed-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarMichael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20220628120705.200617-1-michael@walle.cc


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b9491b2e

drivers/of/fdt.c

+3 −1
Original line number Diff line number Diff line
@@ -1025,6 +1025,7 @@ int __init early_init_dt_scan_chosen_stdout(void) 
	int l;

	const struct earlycon_id *match;

	const void *fdt = initial_boot_params;

	int ret;



	offset = fdt_path_offset(fdt, "/chosen");

	if (offset < 0)
@@ -1057,7 +1058,8 @@ int __init early_init_dt_scan_chosen_stdout(void) 
		if (fdt_node_check_compatible(fdt, offset, match->compatible))

			continue;



		if (of_setup_earlycon(match, offset, options) == 0)

		ret = of_setup_earlycon(match, offset, options);

		if (!ret || ret == -EALREADY)

			return 0;

	}

	return -ENODEV;

drivers/tty/serial/earlycon.c

+3 −0
Original line number Diff line number Diff line
@@ -253,6 +253,9 @@ int __init of_setup_earlycon(const struct earlycon_id *match, 
	bool big_endian;

	u64 addr;



	if (early_con.flags & CON_ENABLED)

		return -EALREADY;



	spin_lock_init(&port->lock);

	port->iotype = UPIO_MEM;

	addr = of_flat_dt_translate_address(node);