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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:28:00 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:28:00 +0000
commit3565071f226432336a54d0193d729fa4508a3394 (patch)
tree4cde13f078f84c0a7785d234fd52edce7c90546a /debian/patches-rt/0039-serial-mpc52xx-Use-port-lock-wrappers.patch
parentAdding upstream version 6.6.15. (diff)
downloadlinux-3565071f226432336a54d0193d729fa4508a3394.tar.xz
linux-3565071f226432336a54d0193d729fa4508a3394.zip
Adding debian version 6.6.15-2.debian/6.6.15-2
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'debian/patches-rt/0039-serial-mpc52xx-Use-port-lock-wrappers.patch')
-rw-r--r--debian/patches-rt/0039-serial-mpc52xx-Use-port-lock-wrappers.patch89
1 files changed, 89 insertions, 0 deletions
diff --git a/debian/patches-rt/0039-serial-mpc52xx-Use-port-lock-wrappers.patch b/debian/patches-rt/0039-serial-mpc52xx-Use-port-lock-wrappers.patch
new file mode 100644
index 0000000000..ee7014a925
--- /dev/null
+++ b/debian/patches-rt/0039-serial-mpc52xx-Use-port-lock-wrappers.patch
@@ -0,0 +1,89 @@
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 14 Sep 2023 20:43:56 +0206
+Subject: [PATCH 039/134] serial: mpc52xx: 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/20230914183831.587273-40-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/mpc52xx_uart.c | 12 ++++++------
+ 1 file changed, 6 insertions(+), 6 deletions(-)
+
+--- a/drivers/tty/serial/mpc52xx_uart.c
++++ b/drivers/tty/serial/mpc52xx_uart.c
+@@ -1096,14 +1096,14 @@ static void
+ mpc52xx_uart_break_ctl(struct uart_port *port, int ctl)
+ {
+ unsigned long flags;
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+
+ if (ctl == -1)
+ psc_ops->command(port, MPC52xx_PSC_START_BRK);
+ else
+ psc_ops->command(port, MPC52xx_PSC_STOP_BRK);
+
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+ }
+
+ static int
+@@ -1214,7 +1214,7 @@ mpc52xx_uart_set_termios(struct uart_por
+ }
+
+ /* Get the lock */
+- spin_lock_irqsave(&port->lock, flags);
++ uart_port_lock_irqsave(port, &flags);
+
+ /* Do our best to flush TX & RX, so we don't lose anything */
+ /* But we don't wait indefinitely ! */
+@@ -1250,7 +1250,7 @@ mpc52xx_uart_set_termios(struct uart_por
+ psc_ops->command(port, MPC52xx_PSC_RX_ENABLE);
+
+ /* We're all set, release the lock */
+- spin_unlock_irqrestore(&port->lock, flags);
++ uart_port_unlock_irqrestore(port, flags);
+ }
+
+ static const char *
+@@ -1477,11 +1477,11 @@ mpc52xx_uart_int(int irq, void *dev_id)
+ struct uart_port *port = dev_id;
+ irqreturn_t ret;
+
+- spin_lock(&port->lock);
++ uart_port_lock(port);
+
+ ret = psc_ops->handle_irq(port);
+
+- spin_unlock(&port->lock);
++ uart_port_unlock(port);
+
+ return ret;
+ }