diff options
Diffstat (limited to 'debian/patches-rt/0036-serial-men_z135_uart-Use-port-lock-wrappers.patch')
-rw-r--r-- | debian/patches-rt/0036-serial-men_z135_uart-Use-port-lock-wrappers.patch | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/debian/patches-rt/0036-serial-men_z135_uart-Use-port-lock-wrappers.patch b/debian/patches-rt/0036-serial-men_z135_uart-Use-port-lock-wrappers.patch new file mode 100644 index 0000000000..11019689b6 --- /dev/null +++ b/debian/patches-rt/0036-serial-men_z135_uart-Use-port-lock-wrappers.patch @@ -0,0 +1,76 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:43:53 +0206 +Subject: [PATCH 036/134] serial: men_z135_uart: 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/20230914183831.587273-37-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/men_z135_uart.c | 8 ++++---- + 1 file changed, 4 insertions(+), 4 deletions(-) + +--- a/drivers/tty/serial/men_z135_uart.c ++++ b/drivers/tty/serial/men_z135_uart.c +@@ -392,7 +392,7 @@ static irqreturn_t men_z135_intr(int irq + if (!irq_id) + goto out; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + /* It's save to write to IIR[7:6] RXC[9:8] */ + iowrite8(irq_id, port->membase + MEN_Z135_STAT_REG); + +@@ -418,7 +418,7 @@ static irqreturn_t men_z135_intr(int irq + handled = true; + } + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + out: + return IRQ_RETVAL(handled); + } +@@ -708,7 +708,7 @@ static void men_z135_set_termios(struct + + baud = uart_get_baud_rate(port, termios, old, 0, uart_freq / 16); + +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + if (tty_termios_baud_rate(termios)) + tty_termios_encode_baud_rate(termios, baud, baud); + +@@ -716,7 +716,7 @@ static void men_z135_set_termios(struct + iowrite32(bd_reg, port->membase + MEN_Z135_BAUD_REG); + + uart_update_timeout(port, termios->c_cflag, baud); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + } + + static const char *men_z135_type(struct uart_port *port) |