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-rw-r--r--debian/patches-rt/0026-serial-linflexuart-Use-port-lock-wrappers.patch143
1 files changed, 143 insertions, 0 deletions
diff --git a/debian/patches-rt/0026-serial-linflexuart-Use-port-lock-wrappers.patch b/debian/patches-rt/0026-serial-linflexuart-Use-port-lock-wrappers.patch
new file mode 100644
index 0000000000..e2a3628ae5
--- /dev/null
+++ b/debian/patches-rt/0026-serial-linflexuart-Use-port-lock-wrappers.patch
@@ -0,0 +1,143 @@
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 14 Sep 2023 20:43:43 +0206
+Subject: [PATCH 026/134] serial: linflexuart: 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/20230914183831.587273-27-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/fsl_linflexuart.c | 26 +++++++++++++-------------
+ 1 file changed, 13 insertions(+), 13 deletions(-)
+
+--- a/drivers/tty/serial/fsl_linflexuart.c
++++ b/drivers/tty/serial/fsl_linflexuart.c
+@@ -203,7 +203,7 @@ static irqreturn_t linflex_txint(int irq
+ struct circ_buf *xmit = &sport->state->xmit;
+ unsigned long flags;
+
+- spin_lock_irqsave(&sport->lock, flags);
++ uart_port_lock_irqsave(sport, &flags);
+
+ if (sport->x_char) {
+ linflex_put_char(sport, sport->x_char);
+@@ -217,7 +217,7 @@ static irqreturn_t linflex_txint(int irq
+
+ linflex_transmit_buffer(sport);
+ out:
+- spin_unlock_irqrestore(&sport->lock, flags);
++ uart_port_unlock_irqrestore(sport, flags);
+ return IRQ_HANDLED;
+ }
+
+@@ -230,7 +230,7 @@ static irqreturn_t linflex_rxint(int irq
+ unsigned char rx;
+ bool brk;
+
+- spin_lock_irqsave(&sport->lock, flags);
++ uart_port_lock_irqsave(sport, &flags);
+
+ status = readl(sport->membase + UARTSR);
+ while (status & LINFLEXD_UARTSR_RMB) {
+@@ -266,7 +266,7 @@ static irqreturn_t linflex_rxint(int irq
+ }
+ }
+
+- spin_unlock_irqrestore(&sport->lock, flags);
++ uart_port_unlock_irqrestore(sport, flags);
+
+ tty_flip_buffer_push(port);
+
+@@ -369,11 +369,11 @@ static int linflex_startup(struct uart_p
+ int ret = 0;
+ unsigned long flags;
+
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+
+ linflex_setup_watermark(port);
+
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+
+ ret = devm_request_irq(port->dev, port->irq, linflex_int, 0,
+ DRIVER_NAME, port);
+@@ -386,14 +386,14 @@ static void linflex_shutdown(struct uart
+ unsigned long ier;
+ unsigned long flags;
+
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+
+ /* disable interrupts */
+ ier = readl(port->membase + LINIER);
+ ier &= ~(LINFLEXD_LINIER_DRIE | LINFLEXD_LINIER_DTIE);
+ writel(ier, port->membase + LINIER);
+
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+
+ devm_free_irq(port->dev, port->irq, port);
+ }
+@@ -474,7 +474,7 @@ linflex_set_termios(struct uart_port *po
+ cr &= ~LINFLEXD_UARTCR_PCE;
+ }
+
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+
+ port->read_status_mask = 0;
+
+@@ -507,7 +507,7 @@ linflex_set_termios(struct uart_port *po
+
+ writel(cr1, port->membase + LINCR1);
+
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+ }
+
+ static const char *linflex_type(struct uart_port *port)
+@@ -646,14 +646,14 @@ linflex_console_write(struct console *co
+ if (sport->sysrq)
+ locked = 0;
+ else if (oops_in_progress)
+- locked = spin_trylock_irqsave(&sport->lock, flags);
++ locked = uart_port_trylock_irqsave(sport, &flags);
+ else
+- spin_lock_irqsave(&sport->lock, flags);
++ uart_port_lock_irqsave(sport, &flags);
+
+ linflex_string_write(sport, s, count);
+
+ if (locked)
+- spin_unlock_irqrestore(&sport->lock, flags);
++ uart_port_unlock_irqrestore(sport, flags);
+ }
+
+ /*