diff options
Diffstat (limited to 'debian/patches-rt/0021-serial-atmel-Use-port-lock-wrappers.patch')
| -rw-r--r-- | debian/patches-rt/0021-serial-atmel-Use-port-lock-wrappers.patch | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/debian/patches-rt/0021-serial-atmel-Use-port-lock-wrappers.patch b/debian/patches-rt/0021-serial-atmel-Use-port-lock-wrappers.patch new file mode 100644 index 0000000000..ab70954a10 --- /dev/null +++ b/debian/patches-rt/0021-serial-atmel-Use-port-lock-wrappers.patch @@ -0,0 +1,119 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:43:38 +0206 +Subject: [PATCH 021/134] serial: atmel: 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/20230914183831.587273-22-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/atmel_serial.c | 24 ++++++++++++------------ + 1 file changed, 12 insertions(+), 12 deletions(-) + +--- a/drivers/tty/serial/atmel_serial.c ++++ b/drivers/tty/serial/atmel_serial.c +@@ -861,7 +861,7 @@ static void atmel_complete_tx_dma(void * + struct dma_chan *chan = atmel_port->chan_tx; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + if (chan) + dmaengine_terminate_all(chan); +@@ -893,7 +893,7 @@ static void atmel_complete_tx_dma(void * + atmel_port->tx_done_mask); + } + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void atmel_release_tx_dma(struct uart_port *port) +@@ -1711,9 +1711,9 @@ static void atmel_tasklet_rx_func(struct + struct uart_port *port = &atmel_port->uart; + + /* The interrupt handler does not take the lock */ +- spin_lock(&port->lock); ++ uart_port_lock(port); + atmel_port->schedule_rx(port); +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + } + + static void atmel_tasklet_tx_func(struct tasklet_struct *t) +@@ -1723,9 +1723,9 @@ static void atmel_tasklet_tx_func(struct + struct uart_port *port = &atmel_port->uart; + + /* The interrupt handler does not take the lock */ +- spin_lock(&port->lock); ++ uart_port_lock(port); + atmel_port->schedule_tx(port); +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + } + + static void atmel_init_property(struct atmel_uart_port *atmel_port, +@@ -2175,7 +2175,7 @@ static void atmel_set_termios(struct uar + } else + mode |= ATMEL_US_PAR_NONE; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + port->read_status_mask = ATMEL_US_OVRE; + if (termios->c_iflag & INPCK) +@@ -2377,22 +2377,22 @@ static void atmel_set_termios(struct uar + else + atmel_disable_ms(port); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void atmel_set_ldisc(struct uart_port *port, struct ktermios *termios) + { + if (termios->c_line == N_PPS) { + port->flags |= UPF_HARDPPS_CD; +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + atmel_enable_ms(port); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + } else { + port->flags &= ~UPF_HARDPPS_CD; + if (!UART_ENABLE_MS(port, termios->c_cflag)) { +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + atmel_disable_ms(port); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + } + } + } |