From 46d0646c4c97208670590a2270db5d3fc7446d50 Mon Sep 17 00:00:00 2001 From: Michael Walle Date: Tue, 28 Jun 2022 14:07:05 +0200 Subject: [PATCH] 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: Rob Herring Signed-off-by: Michael Walle Link: https://lore.kernel.org/r/20220628120705.200617-1-michael@walle.cc Signed-off-by: Greg Kroah-Hartman --- drivers/of/fdt.c | 4 +++- drivers/tty/serial/earlycon.c | 3 +++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index a8f5b65321657..043b12be22d69 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -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; diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c index 57c70851f22a0..88d08ba1ca837 100644 --- a/drivers/tty/serial/earlycon.c +++ b/drivers/tty/serial/earlycon.c @@ -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); -- 2.39.5