diff options
Diffstat (limited to 'debian/patches-rt/0009-serial-core-Introduce-wrapper-to-set-uart_port-cons.patch')
| -rw-r--r-- | debian/patches-rt/0009-serial-core-Introduce-wrapper-to-set-uart_port-cons.patch | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/debian/patches-rt/0009-serial-core-Introduce-wrapper-to-set-uart_port-cons.patch b/debian/patches-rt/0009-serial-core-Introduce-wrapper-to-set-uart_port-cons.patch new file mode 100644 index 0000000000..68106c6e89 --- /dev/null +++ b/debian/patches-rt/0009-serial-core-Introduce-wrapper-to-set-uart_port-cons.patch @@ -0,0 +1,116 @@ +From: John Ogness <john.ogness@linutronix.de> +Date: Wed, 17 Apr 2024 12:13:24 +0000 +Subject: [PATCH 09/46] serial: core: Introduce wrapper to set @uart_port->cons +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.9/older/patches-6.9-rt5.tar.xz + +Introduce uart_port_set_cons() as a wrapper to set @cons of a +uart_port. The wrapper sets @cons under the port lock in order +to prevent @cons from disappearing while another context is +holding the port lock. This is necessary for a follow-up +commit relating to the port lock wrappers, which rely on @cons +not changing between lock and unlock. + +Signed-off-by: John Ogness <john.ogness@linutronix.de> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + drivers/tty/serial/8250/8250_core.c | 6 +++--- + drivers/tty/serial/amba-pl011.c | 2 +- + drivers/tty/serial/serial_core.c | 16 ++++++++-------- + include/linux/serial_core.h | 17 +++++++++++++++++ + 4 files changed, 29 insertions(+), 12 deletions(-) + +--- a/drivers/tty/serial/8250/8250_core.c ++++ b/drivers/tty/serial/8250/8250_core.c +@@ -627,11 +627,11 @@ static int univ8250_console_setup(struct + + port = &serial8250_ports[co->index].port; + /* link port to console */ +- port->cons = co; ++ uart_port_set_cons(port, co); + + retval = serial8250_console_setup(port, options, false); + if (retval != 0) +- port->cons = NULL; ++ uart_port_set_cons(port, NULL); + return retval; + } + +@@ -689,7 +689,7 @@ static int univ8250_console_match(struct + continue; + + co->index = i; +- port->cons = co; ++ uart_port_set_cons(port, co); + return serial8250_console_setup(port, options, true); + } + +--- a/drivers/tty/serial/amba-pl011.c ++++ b/drivers/tty/serial/amba-pl011.c +@@ -2488,7 +2488,7 @@ static int pl011_console_match(struct co + continue; + + co->index = i; +- port->cons = co; ++ uart_port_set_cons(port, co); + return pl011_console_setup(co, options); + } + +--- a/drivers/tty/serial/serial_core.c ++++ b/drivers/tty/serial/serial_core.c +@@ -3172,8 +3172,15 @@ static int serial_core_add_one_port(stru + state->uart_port = uport; + uport->state = state; + ++ /* ++ * If this port is in use as a console then the spinlock is already ++ * initialised. ++ */ ++ if (!uart_console_registered(uport)) ++ uart_port_spin_lock_init(uport); ++ + state->pm_state = UART_PM_STATE_UNDEFINED; +- uport->cons = drv->cons; ++ uart_port_set_cons(uport, drv->cons); + uport->minor = drv->tty_driver->minor_start + uport->line; + uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name, + drv->tty_driver->name_base + uport->line); +@@ -3182,13 +3189,6 @@ static int serial_core_add_one_port(stru + goto out; + } + +- /* +- * If this port is in use as a console then the spinlock is already +- * initialised. +- */ +- if (!uart_console_registered(uport)) +- uart_port_spin_lock_init(uport); +- + if (uport->cons && uport->dev) + of_console_check(uport->dev->of_node, uport->cons->name, uport->line); + +--- a/include/linux/serial_core.h ++++ b/include/linux/serial_core.h +@@ -610,6 +610,23 @@ static inline void __uart_port_unlock_ir + } + + /** ++ * uart_port_set_cons - Safely set the @cons field for a uart ++ * @up: The uart port to set ++ * @con: The new console to set to ++ * ++ * This function must be used to set @up->cons. It uses the port lock to ++ * synchronize with the port lock wrappers in order to ensure that the console ++ * cannot change or disappear while another context is holding the port lock. ++ */ ++static inline void uart_port_set_cons(struct uart_port *up, struct console *con) ++{ ++ unsigned long flags; ++ ++ __uart_port_lock_irqsave(up, &flags); ++ up->cons = con; ++ __uart_port_unlock_irqrestore(up, flags); ++} ++/** + * uart_port_lock - Lock the UART port + * @up: Pointer to UART port structure + */ |