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-rw-r--r--debian/patches-rt/0032-serial-liteuart-Use-port-lock-wrappers.patch110
1 files changed, 110 insertions, 0 deletions
diff --git a/debian/patches-rt/0032-serial-liteuart-Use-port-lock-wrappers.patch b/debian/patches-rt/0032-serial-liteuart-Use-port-lock-wrappers.patch
new file mode 100644
index 0000000000..ae679c098c
--- /dev/null
+++ b/debian/patches-rt/0032-serial-liteuart-Use-port-lock-wrappers.patch
@@ -0,0 +1,110 @@
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 14 Sep 2023 20:43:49 +0206
+Subject: [PATCH 032/134] serial: liteuart: 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>
+Acked-by: Gabriel Somlo <gsomlo@gmail.com>
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Link: https://lore.kernel.org/r/20230914183831.587273-33-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/liteuart.c | 20 ++++++++++----------
+ 1 file changed, 10 insertions(+), 10 deletions(-)
+
+--- a/drivers/tty/serial/liteuart.c
++++ b/drivers/tty/serial/liteuart.c
+@@ -139,13 +139,13 @@ static irqreturn_t liteuart_interrupt(in
+ * if polling, the context would be "in_serving_softirq", so use
+ * irq[save|restore] spin_lock variants to cover all possibilities
+ */
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+ isr = litex_read8(port->membase + OFF_EV_PENDING) & uart->irq_reg;
+ if (isr & EV_RX)
+ liteuart_rx_chars(port);
+ if (isr & EV_TX)
+ liteuart_tx_chars(port);
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+
+ return IRQ_RETVAL(isr);
+ }
+@@ -195,10 +195,10 @@ static int liteuart_startup(struct uart_
+ }
+ }
+
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+ /* only enabling rx irqs during startup */
+ liteuart_update_irq_reg(port, true, EV_RX);
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+
+ if (!port->irq) {
+ timer_setup(&uart->timer, liteuart_timer, 0);
+@@ -213,9 +213,9 @@ static void liteuart_shutdown(struct uar
+ struct liteuart_port *uart = to_liteuart_port(port);
+ unsigned long flags;
+
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+ liteuart_update_irq_reg(port, false, EV_RX | EV_TX);
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+
+ if (port->irq)
+ free_irq(port->irq, port);
+@@ -229,13 +229,13 @@ static void liteuart_set_termios(struct
+ unsigned int baud;
+ unsigned long flags;
+
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+
+ /* update baudrate */
+ baud = uart_get_baud_rate(port, new, old, 0, 460800);
+ uart_update_timeout(port, new->c_cflag, baud);
+
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+ }
+
+ static const char *liteuart_type(struct uart_port *port)
+@@ -382,9 +382,9 @@ static void liteuart_console_write(struc
+ uart = (struct liteuart_port *)xa_load(&liteuart_array, co->index);
+ port = &uart->port;
+
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+ uart_console_write(port, s, count, liteuart_putchar);
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+ }
+
+ static int liteuart_console_setup(struct console *co, char *options)