From 3791ea69a4858b81e0277f695ca40f5aae40f312 Mon Sep 17 00:00:00 2001 From: Claudiu Beznea Date: Wed, 6 Nov 2024 14:01:12 +0200 Subject: serial: sh-sci: Clean sci_ports[0] after at earlycon exit The early_console_setup() function initializes the sci_ports[0].port with an object of type struct uart_port obtained from the object of type struct earlycon_device received as argument by the early_console_setup(). It may happen that later, when the rest of the serial ports are probed, the serial port that was used as earlycon (e.g., port A) to be mapped to a different position in sci_ports[] and the slot 0 to be used by a different serial port (e.g., port B), as follows: sci_ports[0] = port A sci_ports[X] = port B In this case, the new port mapped at index zero will have associated data that was used for earlycon. In case this happens, after Linux boot, any access to the serial port that maps on sci_ports[0] (port A) will block the serial port that was used as earlycon (port B). To fix this, add early_console_exit() that clean the sci_ports[0] at earlycon exit time. Fixes: 0b0cced19ab1 ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support") Cc: stable@vger.kernel.org Signed-off-by: Claudiu Beznea Link: https://lore.kernel.org/r/20241106120118.1719888-4-claudiu.beznea.uj@bp.renesas.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/sh-sci.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'drivers/tty') diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index df523c744423..136e0c257af1 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -3535,6 +3535,32 @@ sh_early_platform_init_buffer("earlyprintk", &sci_driver, #ifdef CONFIG_SERIAL_SH_SCI_EARLYCON static struct plat_sci_port port_cfg __initdata; +static int early_console_exit(struct console *co) +{ + struct sci_port *sci_port = &sci_ports[0]; + struct uart_port *port = &sci_port->port; + unsigned long flags; + int locked = 1; + + if (port->sysrq) + locked = 0; + else if (oops_in_progress) + locked = uart_port_trylock_irqsave(port, &flags); + else + uart_port_lock_irqsave(port, &flags); + + /* + * Clean the slot used by earlycon. A new SCI device might + * map to this slot. + */ + memset(sci_ports, 0, sizeof(*sci_port)); + + if (locked) + uart_port_unlock_irqrestore(port, flags); + + return 0; +} + static int __init early_console_setup(struct earlycon_device *device, int type) { @@ -3551,6 +3577,8 @@ static int __init early_console_setup(struct earlycon_device *device, SCSCR_RE | SCSCR_TE | port_cfg.scscr); device->con->write = serial_console_write; + device->con->exit = early_console_exit; + return 0; } static int __init sci_early_console_setup(struct earlycon_device *device, -- cgit v1.2.3