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-rw-r--r--debian/patches-rt/0063-serial-st-asc-Use-port-lock-wrappers.patch110
1 files changed, 110 insertions, 0 deletions
diff --git a/debian/patches-rt/0063-serial-st-asc-Use-port-lock-wrappers.patch b/debian/patches-rt/0063-serial-st-asc-Use-port-lock-wrappers.patch
new file mode 100644
index 0000000000..99f4358e61
--- /dev/null
+++ b/debian/patches-rt/0063-serial-st-asc-Use-port-lock-wrappers.patch
@@ -0,0 +1,110 @@
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 14 Sep 2023 20:44:20 +0206
+Subject: [PATCH 063/134] serial: st-asc: 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/20230914183831.587273-64-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/st-asc.c | 18 +++++++++---------
+ 1 file changed, 9 insertions(+), 9 deletions(-)
+
+--- a/drivers/tty/serial/st-asc.c
++++ b/drivers/tty/serial/st-asc.c
+@@ -319,7 +319,7 @@ static irqreturn_t asc_interrupt(int irq
+ struct uart_port *port = ptr;
+ u32 status;
+
+- spin_lock(&port->lock);
++ uart_port_lock(port);
+
+ status = asc_in(port, ASC_STA);
+
+@@ -334,7 +334,7 @@ static irqreturn_t asc_interrupt(int irq
+ asc_transmit_chars(port);
+ }
+
+- spin_unlock(&port->lock);
++ uart_port_unlock(port);
+
+ return IRQ_HANDLED;
+ }
+@@ -452,10 +452,10 @@ static void asc_pm(struct uart_port *por
+ * we can come to turning it off. Note this is not called with
+ * the port spinlock held.
+ */
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+ ctl = asc_in(port, ASC_CTL) & ~ASC_CTL_RUN;
+ asc_out(port, ASC_CTL, ctl);
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+ clk_disable_unprepare(ascport->clk);
+ break;
+ }
+@@ -480,7 +480,7 @@ static void asc_set_termios(struct uart_
+ baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
+ cflag = termios->c_cflag;
+
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+
+ /* read control register */
+ ctrl_val = asc_in(port, ASC_CTL);
+@@ -594,7 +594,7 @@ static void asc_set_termios(struct uart_
+ /* write final value and enable port */
+ asc_out(port, ASC_CTL, (ctrl_val | ASC_CTL_RUN));
+
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+ }
+
+ static const char *asc_type(struct uart_port *port)
+@@ -849,9 +849,9 @@ static void asc_console_write(struct con
+ if (port->sysrq)
+ locked = 0; /* asc_interrupt has already claimed the lock */
+ else if (oops_in_progress)
+- locked = spin_trylock_irqsave(&port->lock, flags);
++ locked = uart_port_trylock_irqsave(port, &flags);
+ else
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+
+ /*
+ * Disable interrupts so we don't get the IRQ line bouncing
+@@ -869,7 +869,7 @@ static void asc_console_write(struct con
+ asc_out(port, ASC_INTEN, intenable);
+
+ if (locked)
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+ }
+
+ static int asc_console_setup(struct console *co, char *options)