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-rw-r--r--debian/patches-rt/0048-serial-pxa-Use-port-lock-wrappers.patch150
1 files changed, 150 insertions, 0 deletions
diff --git a/debian/patches-rt/0048-serial-pxa-Use-port-lock-wrappers.patch b/debian/patches-rt/0048-serial-pxa-Use-port-lock-wrappers.patch
new file mode 100644
index 0000000000..b0df211b6f
--- /dev/null
+++ b/debian/patches-rt/0048-serial-pxa-Use-port-lock-wrappers.patch
@@ -0,0 +1,150 @@
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 14 Sep 2023 20:44:05 +0206
+Subject: [PATCH 048/134] serial: pxa: 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/20230914183831.587273-49-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/pxa.c | 30 +++++++++++++++---------------
+ 1 file changed, 15 insertions(+), 15 deletions(-)
+
+--- a/drivers/tty/serial/pxa.c
++++ b/drivers/tty/serial/pxa.c
+@@ -225,14 +225,14 @@ static inline irqreturn_t serial_pxa_irq
+ iir = serial_in(up, UART_IIR);
+ if (iir & UART_IIR_NO_INT)
+ return IRQ_NONE;
+- spin_lock(&up->port.lock);
++ uart_port_lock(&up->port);
+ lsr = serial_in(up, UART_LSR);
+ if (lsr & UART_LSR_DR)
+ receive_chars(up, &lsr);
+ check_modem_status(up);
+ if (lsr & UART_LSR_THRE)
+ transmit_chars(up);
+- spin_unlock(&up->port.lock);
++ uart_port_unlock(&up->port);
+ return IRQ_HANDLED;
+ }
+
+@@ -242,9 +242,9 @@ static unsigned int serial_pxa_tx_empty(
+ unsigned long flags;
+ unsigned int ret;
+
+- spin_lock_irqsave(&up->port.lock, flags);
++ uart_port_lock_irqsave(&up->port, &flags);
+ ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
+- spin_unlock_irqrestore(&up->port.lock, flags);
++ uart_port_unlock_irqrestore(&up->port, flags);
+
+ return ret;
+ }
+@@ -295,13 +295,13 @@ static void serial_pxa_break_ctl(struct
+ struct uart_pxa_port *up = (struct uart_pxa_port *)port;
+ unsigned long flags;
+
+- spin_lock_irqsave(&up->port.lock, flags);
++ uart_port_lock_irqsave(&up->port, &flags);
+ if (break_state == -1)
+ up->lcr |= UART_LCR_SBC;
+ else
+ up->lcr &= ~UART_LCR_SBC;
+ serial_out(up, UART_LCR, up->lcr);
+- spin_unlock_irqrestore(&up->port.lock, flags);
++ uart_port_unlock_irqrestore(&up->port, flags);
+ }
+
+ static int serial_pxa_startup(struct uart_port *port)
+@@ -346,10 +346,10 @@ static int serial_pxa_startup(struct uar
+ */
+ serial_out(up, UART_LCR, UART_LCR_WLEN8);
+
+- spin_lock_irqsave(&up->port.lock, flags);
++ uart_port_lock_irqsave(&up->port, &flags);
+ up->port.mctrl |= TIOCM_OUT2;
+ serial_pxa_set_mctrl(&up->port, up->port.mctrl);
+- spin_unlock_irqrestore(&up->port.lock, flags);
++ uart_port_unlock_irqrestore(&up->port, flags);
+
+ /*
+ * Finally, enable interrupts. Note: Modem status interrupts
+@@ -383,10 +383,10 @@ static void serial_pxa_shutdown(struct u
+ up->ier = 0;
+ serial_out(up, UART_IER, 0);
+
+- spin_lock_irqsave(&up->port.lock, flags);
++ uart_port_lock_irqsave(&up->port, &flags);
+ up->port.mctrl &= ~TIOCM_OUT2;
+ serial_pxa_set_mctrl(&up->port, up->port.mctrl);
+- spin_unlock_irqrestore(&up->port.lock, flags);
++ uart_port_unlock_irqrestore(&up->port, flags);
+
+ /*
+ * Disable break condition and FIFOs
+@@ -434,7 +434,7 @@ serial_pxa_set_termios(struct uart_port
+ * 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);
+
+ /*
+ * Ensure the port will be enabled.
+@@ -504,7 +504,7 @@ serial_pxa_set_termios(struct uart_port
+ up->lcr = cval; /* Save LCR */
+ serial_pxa_set_mctrl(&up->port, up->port.mctrl);
+ serial_out(up, UART_FCR, fcr);
+- spin_unlock_irqrestore(&up->port.lock, flags);
++ uart_port_unlock_irqrestore(&up->port, flags);
+ }
+
+ static void
+@@ -608,9 +608,9 @@ serial_pxa_console_write(struct console
+ 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
+@@ -628,7 +628,7 @@ serial_pxa_console_write(struct console
+ serial_out(up, UART_IER, ier);
+
+ if (locked)
+- spin_unlock(&up->port.lock);
++ uart_port_unlock(&up->port);
+ local_irq_restore(flags);
+ clk_disable(up->clk);
+