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-rw-r--r--debian/patches-rt/0016-serial-amba-pl010-Use-port-lock-wrappers.patch112
1 files changed, 112 insertions, 0 deletions
diff --git a/debian/patches-rt/0016-serial-amba-pl010-Use-port-lock-wrappers.patch b/debian/patches-rt/0016-serial-amba-pl010-Use-port-lock-wrappers.patch
new file mode 100644
index 0000000000..f3ba735bfc
--- /dev/null
+++ b/debian/patches-rt/0016-serial-amba-pl010-Use-port-lock-wrappers.patch
@@ -0,0 +1,112 @@
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 14 Sep 2023 20:43:33 +0206
+Subject: [PATCH 016/134] serial: amba-pl010: 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/20230914183831.587273-17-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/amba-pl010.c | 20 ++++++++++----------
+ 1 file changed, 10 insertions(+), 10 deletions(-)
+
+--- a/drivers/tty/serial/amba-pl010.c
++++ b/drivers/tty/serial/amba-pl010.c
+@@ -207,7 +207,7 @@ static irqreturn_t pl010_int(int irq, vo
+ unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
+ int handled = 0;
+
+- spin_lock(&port->lock);
++ uart_port_lock(port);
+
+ status = readb(port->membase + UART010_IIR);
+ if (status) {
+@@ -228,7 +228,7 @@ static irqreturn_t pl010_int(int irq, vo
+ handled = 1;
+ }
+
+- spin_unlock(&port->lock);
++ uart_port_unlock(port);
+
+ return IRQ_RETVAL(handled);
+ }
+@@ -270,14 +270,14 @@ static void pl010_break_ctl(struct uart_
+ unsigned long flags;
+ unsigned int lcr_h;
+
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+ lcr_h = readb(port->membase + UART010_LCRH);
+ if (break_state == -1)
+ lcr_h |= UART01x_LCRH_BRK;
+ else
+ lcr_h &= ~UART01x_LCRH_BRK;
+ writel(lcr_h, port->membase + UART010_LCRH);
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+ }
+
+ static int pl010_startup(struct uart_port *port)
+@@ -385,7 +385,7 @@ pl010_set_termios(struct uart_port *port
+ if (port->fifosize > 1)
+ lcr_h |= UART01x_LCRH_FEN;
+
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+
+ /*
+ * Update the per-port timeout.
+@@ -438,22 +438,22 @@ pl010_set_termios(struct uart_port *port
+ writel(lcr_h, port->membase + UART010_LCRH);
+ writel(old_cr, port->membase + UART010_CR);
+
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+ }
+
+ static void pl010_set_ldisc(struct uart_port *port, struct ktermios *termios)
+ {
+ if (termios->c_line == N_PPS) {
+ port->flags |= UPF_HARDPPS_CD;
+- spin_lock_irq(&port->lock);
++ uart_port_lock_irq(port);
+ pl010_enable_ms(port);
+- spin_unlock_irq(&port->lock);
++ uart_port_unlock_irq(port);
+ } else {
+ port->flags &= ~UPF_HARDPPS_CD;
+ if (!UART_ENABLE_MS(port, termios->c_cflag)) {
+- spin_lock_irq(&port->lock);
++ uart_port_lock_irq(port);
+ pl010_disable_ms(port);
+- spin_unlock_irq(&port->lock);
++ uart_port_unlock_irq(port);
+ }
+ }
+ }