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Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/0039-serial-mpc52xx-Use-port-lock-wrappers.patch | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/debian/patches-rt/0039-serial-mpc52xx-Use-port-lock-wrappers.patch b/debian/patches-rt/0039-serial-mpc52xx-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..ee7014a92 --- /dev/null +++ b/debian/patches-rt/0039-serial-mpc52xx-Use-port-lock-wrappers.patch @@ -0,0 +1,89 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:43:56 +0206 +Subject: [PATCH 039/134] serial: mpc52xx: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +Signed-off-by: John Ogness <john.ogness@linutronix.de> +Link: https://lore.kernel.org/r/20230914183831.587273-40-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + drivers/tty/serial/mpc52xx_uart.c | 12 ++++++------ + 1 file changed, 6 insertions(+), 6 deletions(-) + +--- a/drivers/tty/serial/mpc52xx_uart.c ++++ b/drivers/tty/serial/mpc52xx_uart.c +@@ -1096,14 +1096,14 @@ static void + mpc52xx_uart_break_ctl(struct uart_port *port, int ctl) + { + unsigned long flags; +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + if (ctl == -1) + psc_ops->command(port, MPC52xx_PSC_START_BRK); + else + psc_ops->command(port, MPC52xx_PSC_STOP_BRK); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int +@@ -1214,7 +1214,7 @@ mpc52xx_uart_set_termios(struct uart_por + } + + /* Get the lock */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Do our best to flush TX & RX, so we don't lose anything */ + /* But we don't wait indefinitely ! */ +@@ -1250,7 +1250,7 @@ mpc52xx_uart_set_termios(struct uart_por + psc_ops->command(port, MPC52xx_PSC_RX_ENABLE); + + /* We're all set, release the lock */ +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char * +@@ -1477,11 +1477,11 @@ mpc52xx_uart_int(int irq, void *dev_id) + struct uart_port *port = dev_id; + irqreturn_t ret; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + ret = psc_ops->handle_irq(port); + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return ret; + } |