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-rw-r--r--debian/patches-rt/0019-serial-ar933x-Use-port-lock-wrappers.patch144
1 files changed, 144 insertions, 0 deletions
diff --git a/debian/patches-rt/0019-serial-ar933x-Use-port-lock-wrappers.patch b/debian/patches-rt/0019-serial-ar933x-Use-port-lock-wrappers.patch
new file mode 100644
index 0000000000..61a5d3b1a6
--- /dev/null
+++ b/debian/patches-rt/0019-serial-ar933x-Use-port-lock-wrappers.patch
@@ -0,0 +1,144 @@
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 14 Sep 2023 20:43:36 +0206
+Subject: [PATCH 019/134] serial: ar933x: 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/20230914183831.587273-20-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/ar933x_uart.c | 26 +++++++++++++-------------
+ 1 file changed, 13 insertions(+), 13 deletions(-)
+
+--- a/drivers/tty/serial/ar933x_uart.c
++++ b/drivers/tty/serial/ar933x_uart.c
+@@ -133,9 +133,9 @@ static unsigned int ar933x_uart_tx_empty
+ unsigned long flags;
+ unsigned int rdata;
+
+- spin_lock_irqsave(&up->port.lock, flags);
++ uart_port_lock_irqsave(&up->port, &flags);
+ rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
+- spin_unlock_irqrestore(&up->port.lock, flags);
++ uart_port_unlock_irqrestore(&up->port, flags);
+
+ return (rdata & AR933X_UART_DATA_TX_CSR) ? 0 : TIOCSER_TEMT;
+ }
+@@ -220,14 +220,14 @@ static void ar933x_uart_break_ctl(struct
+ container_of(port, struct ar933x_uart_port, port);
+ unsigned long flags;
+
+- spin_lock_irqsave(&up->port.lock, flags);
++ uart_port_lock_irqsave(&up->port, &flags);
+ if (break_state == -1)
+ ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
+ AR933X_UART_CS_TX_BREAK);
+ else
+ ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
+ AR933X_UART_CS_TX_BREAK);
+- spin_unlock_irqrestore(&up->port.lock, flags);
++ uart_port_unlock_irqrestore(&up->port, flags);
+ }
+
+ /*
+@@ -318,7 +318,7 @@ static void ar933x_uart_set_termios(stru
+ * Ok, we're now changing the port state. Do it with
+ * interrupts disabled.
+ */
+- spin_lock_irqsave(&up->port.lock, flags);
++ uart_port_lock_irqsave(&up->port, &flags);
+
+ /* disable the UART */
+ ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
+@@ -352,7 +352,7 @@ static void ar933x_uart_set_termios(stru
+ AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S,
+ AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S);
+
+- spin_unlock_irqrestore(&up->port.lock, flags);
++ uart_port_unlock_irqrestore(&up->port, flags);
+
+ if (tty_termios_baud_rate(new))
+ tty_termios_encode_baud_rate(new, baud, baud);
+@@ -450,7 +450,7 @@ static irqreturn_t ar933x_uart_interrupt
+ if ((status & AR933X_UART_CS_HOST_INT) == 0)
+ return IRQ_NONE;
+
+- spin_lock(&up->port.lock);
++ uart_port_lock(&up->port);
+
+ status = ar933x_uart_read(up, AR933X_UART_INT_REG);
+ status &= ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
+@@ -468,7 +468,7 @@ static irqreturn_t ar933x_uart_interrupt
+ ar933x_uart_tx_chars(up);
+ }
+
+- spin_unlock(&up->port.lock);
++ uart_port_unlock(&up->port);
+
+ return IRQ_HANDLED;
+ }
+@@ -485,7 +485,7 @@ static int ar933x_uart_startup(struct ua
+ if (ret)
+ return ret;
+
+- spin_lock_irqsave(&up->port.lock, flags);
++ uart_port_lock_irqsave(&up->port, &flags);
+
+ /* Enable HOST interrupts */
+ ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
+@@ -498,7 +498,7 @@ static int ar933x_uart_startup(struct ua
+ /* Enable RX interrupts */
+ ar933x_uart_start_rx_interrupt(up);
+
+- spin_unlock_irqrestore(&up->port.lock, flags);
++ uart_port_unlock_irqrestore(&up->port, flags);
+
+ return 0;
+ }
+@@ -632,9 +632,9 @@ static void ar933x_uart_console_write(st
+ if (up->port.sysrq)
+ locked = 0;
+ else if (oops_in_progress)
+- locked = spin_trylock(&up->port.lock);
++ locked = uart_port_trylock(&up->port);
+ else
+- spin_lock(&up->port.lock);
++ uart_port_lock(&up->port);
+
+ /*
+ * First save the IER then disable the interrupts
+@@ -654,7 +654,7 @@ static void ar933x_uart_console_write(st
+ ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_ALLINTS);
+
+ if (locked)
+- spin_unlock(&up->port.lock);
++ uart_port_unlock(&up->port);
+
+ local_irq_restore(flags);
+ }