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-rw-r--r--debian/patches-rt/0054-serial-sb1250-duart-Use-port-lock-wrappers.patch85
1 files changed, 85 insertions, 0 deletions
diff --git a/debian/patches-rt/0054-serial-sb1250-duart-Use-port-lock-wrappers.patch b/debian/patches-rt/0054-serial-sb1250-duart-Use-port-lock-wrappers.patch
new file mode 100644
index 0000000000..e5aeb528fe
--- /dev/null
+++ b/debian/patches-rt/0054-serial-sb1250-duart-Use-port-lock-wrappers.patch
@@ -0,0 +1,85 @@
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 14 Sep 2023 20:44:11 +0206
+Subject: [PATCH 054/134] serial: sb1250-duart: 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/20230914183831.587273-55-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/sb1250-duart.c | 12 ++++++------
+ 1 file changed, 6 insertions(+), 6 deletions(-)
+
+--- a/drivers/tty/serial/sb1250-duart.c
++++ b/drivers/tty/serial/sb1250-duart.c
+@@ -610,7 +610,7 @@ static void sbd_set_termios(struct uart_
+ else
+ aux &= ~M_DUART_CTS_CHNG_ENA;
+
+- spin_lock(&uport->lock);
++ uart_port_lock(uport);
+
+ if (sport->tx_stopped)
+ command |= M_DUART_TX_DIS;
+@@ -632,7 +632,7 @@ static void sbd_set_termios(struct uart_
+
+ write_sbdchn(sport, R_DUART_CMD, command);
+
+- spin_unlock(&uport->lock);
++ uart_port_unlock(uport);
+ }
+
+
+@@ -839,22 +839,22 @@ static void sbd_console_write(struct con
+ unsigned int mask;
+
+ /* Disable transmit interrupts and enable the transmitter. */
+- spin_lock_irqsave(&uport->lock, flags);
++ uart_port_lock_irqsave(uport, &flags);
+ mask = read_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2));
+ write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2),
+ mask & ~M_DUART_IMR_TX);
+ write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_EN);
+- spin_unlock_irqrestore(&uport->lock, flags);
++ uart_port_unlock_irqrestore(uport, flags);
+
+ uart_console_write(&sport->port, s, count, sbd_console_putchar);
+
+ /* Restore transmit interrupts and the transmitter enable. */
+- spin_lock_irqsave(&uport->lock, flags);
++ uart_port_lock_irqsave(uport, &flags);
+ sbd_line_drain(sport);
+ if (sport->tx_stopped)
+ write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_DIS);
+ write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2), mask);
+- spin_unlock_irqrestore(&uport->lock, flags);
++ uart_port_unlock_irqrestore(uport, flags);
+ }
+
+ static int __init sbd_console_setup(struct console *co, char *options)