diff options
Diffstat (limited to 'debian/patches-rt/0004-serial-8250_aspeed_vuart-Use-port-lock-wrappers.patch')
-rw-r--r-- | debian/patches-rt/0004-serial-8250_aspeed_vuart-Use-port-lock-wrappers.patch | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/debian/patches-rt/0004-serial-8250_aspeed_vuart-Use-port-lock-wrappers.patch b/debian/patches-rt/0004-serial-8250_aspeed_vuart-Use-port-lock-wrappers.patch new file mode 100644 index 0000000000..eb65ac58fc --- /dev/null +++ b/debian/patches-rt/0004-serial-8250_aspeed_vuart-Use-port-lock-wrappers.patch @@ -0,0 +1,61 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:43:21 +0206 +Subject: [PATCH 004/134] serial: 8250_aspeed_vuart: 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/20230914183831.587273-5-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/8250/8250_aspeed_vuart.c | 6 +++--- + 1 file changed, 3 insertions(+), 3 deletions(-) + +--- a/drivers/tty/serial/8250/8250_aspeed_vuart.c ++++ b/drivers/tty/serial/8250/8250_aspeed_vuart.c +@@ -288,9 +288,9 @@ static void aspeed_vuart_set_throttle(st + struct uart_8250_port *up = up_to_u8250p(port); + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + __aspeed_vuart_set_throttle(up, throttle); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void aspeed_vuart_throttle(struct uart_port *port) +@@ -340,7 +340,7 @@ static int aspeed_vuart_handle_irq(struc + if (iir & UART_IIR_NO_INT) + return 0; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + lsr = serial_port_in(port, UART_LSR); + |