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-rw-r--r--debian/patches-rt/0021-serial-atmel-Use-port-lock-wrappers.patch119
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);
+ }
+ }
+ }