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-rw-r--r--debian/patches-rt/0050-serial-rda-Use-port-lock-wrappers.patch177
1 files changed, 177 insertions, 0 deletions
diff --git a/debian/patches-rt/0050-serial-rda-Use-port-lock-wrappers.patch b/debian/patches-rt/0050-serial-rda-Use-port-lock-wrappers.patch
new file mode 100644
index 0000000000..6d51972bcd
--- /dev/null
+++ b/debian/patches-rt/0050-serial-rda-Use-port-lock-wrappers.patch
@@ -0,0 +1,177 @@
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 14 Sep 2023 20:44:07 +0206
+Subject: [PATCH 050/134] serial: rda: 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/20230914183831.587273-51-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/rda-uart.c | 34 +++++++++++++++++-----------------
+ 1 file changed, 17 insertions(+), 17 deletions(-)
+
+--- a/drivers/tty/serial/rda-uart.c
++++ b/drivers/tty/serial/rda-uart.c
+@@ -139,12 +139,12 @@ static unsigned int rda_uart_tx_empty(st
+ unsigned int ret;
+ u32 val;
+
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+
+ val = rda_uart_read(port, RDA_UART_STATUS);
+ ret = (val & RDA_UART_TX_FIFO_MASK) ? TIOCSER_TEMT : 0;
+
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+
+ return ret;
+ }
+@@ -246,7 +246,7 @@ static void rda_uart_set_termios(struct
+ unsigned int baud;
+ u32 irq_mask;
+
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+
+ baud = uart_get_baud_rate(port, termios, old, 9600, port->uartclk / 4);
+ rda_uart_change_baudrate(rda_port, baud);
+@@ -325,7 +325,7 @@ static void rda_uart_set_termios(struct
+ /* update the per-port timeout */
+ uart_update_timeout(port, termios->c_cflag, baud);
+
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+ }
+
+ static void rda_uart_send_chars(struct uart_port *port)
+@@ -408,7 +408,7 @@ static irqreturn_t rda_interrupt(int irq
+ unsigned long flags;
+ u32 val, irq_mask;
+
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+
+ /* Clear IRQ cause */
+ val = rda_uart_read(port, RDA_UART_IRQ_CAUSE);
+@@ -425,7 +425,7 @@ static irqreturn_t rda_interrupt(int irq
+ rda_uart_send_chars(port);
+ }
+
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+
+ return IRQ_HANDLED;
+ }
+@@ -436,16 +436,16 @@ static int rda_uart_startup(struct uart_
+ int ret;
+ u32 val;
+
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+ rda_uart_write(port, 0, RDA_UART_IRQ_MASK);
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+
+ ret = request_irq(port->irq, rda_interrupt, IRQF_NO_SUSPEND,
+ "rda-uart", port);
+ if (ret)
+ return ret;
+
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+
+ val = rda_uart_read(port, RDA_UART_CTRL);
+ val |= RDA_UART_ENABLE;
+@@ -456,7 +456,7 @@ static int rda_uart_startup(struct uart_
+ val |= (RDA_UART_RX_DATA_AVAILABLE | RDA_UART_RX_TIMEOUT);
+ rda_uart_write(port, val, RDA_UART_IRQ_MASK);
+
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+
+ return 0;
+ }
+@@ -466,7 +466,7 @@ static void rda_uart_shutdown(struct uar
+ unsigned long flags;
+ u32 val;
+
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+
+ rda_uart_stop_tx(port);
+ rda_uart_stop_rx(port);
+@@ -475,7 +475,7 @@ static void rda_uart_shutdown(struct uar
+ val &= ~RDA_UART_ENABLE;
+ rda_uart_write(port, val, RDA_UART_CTRL);
+
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+ }
+
+ static const char *rda_uart_type(struct uart_port *port)
+@@ -515,7 +515,7 @@ static void rda_uart_config_port(struct
+ rda_uart_request_port(port);
+ }
+
+- spin_lock_irqsave(&port->lock, irq_flags);
++ uart_port_lock_irqsave(port, &irq_flags);
+
+ /* Clear mask, so no surprise interrupts. */
+ rda_uart_write(port, 0, RDA_UART_IRQ_MASK);
+@@ -523,7 +523,7 @@ static void rda_uart_config_port(struct
+ /* Clear status register */
+ rda_uart_write(port, 0, RDA_UART_STATUS);
+
+- spin_unlock_irqrestore(&port->lock, irq_flags);
++ uart_port_unlock_irqrestore(port, irq_flags);
+ }
+
+ static void rda_uart_release_port(struct uart_port *port)
+@@ -597,9 +597,9 @@ static void rda_uart_port_write(struct u
+ if (port->sysrq) {
+ locked = 0;
+ } else if (oops_in_progress) {
+- locked = spin_trylock(&port->lock);
++ locked = uart_port_trylock(port);
+ } else {
+- spin_lock(&port->lock);
++ uart_port_lock(port);
+ locked = 1;
+ }
+
+@@ -615,7 +615,7 @@ static void rda_uart_port_write(struct u
+ rda_uart_write(port, old_irq_mask, RDA_UART_IRQ_MASK);
+
+ if (locked)
+- spin_unlock(&port->lock);
++ uart_port_unlock(port);
+
+ local_irq_restore(flags);
+ }