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Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/0020-serial-arc_uart-Use-port-lock-wrappers.patch | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/debian/patches-rt/0020-serial-arc_uart-Use-port-lock-wrappers.patch b/debian/patches-rt/0020-serial-arc_uart-Use-port-lock-wrappers.patch new file mode 100644 index 0000000000..bc7be2c4d3 --- /dev/null +++ b/debian/patches-rt/0020-serial-arc_uart-Use-port-lock-wrappers.patch @@ -0,0 +1,97 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:43:37 +0206 +Subject: [PATCH 020/134] serial: arc_uart: 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/20230914183831.587273-21-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/arc_uart.c | 16 ++++++++-------- + 1 file changed, 8 insertions(+), 8 deletions(-) + +--- a/drivers/tty/serial/arc_uart.c ++++ b/drivers/tty/serial/arc_uart.c +@@ -279,9 +279,9 @@ static irqreturn_t arc_serial_isr(int ir + if (status & RXIENB) { + + /* already in ISR, no need of xx_irqsave */ +- spin_lock(&port->lock); ++ uart_port_lock(port); + arc_serial_rx_chars(port, status); +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + } + + if ((status & TXIENB) && (status & TXEMPTY)) { +@@ -291,12 +291,12 @@ static irqreturn_t arc_serial_isr(int ir + */ + UART_TX_IRQ_DISABLE(port); + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + if (!uart_tx_stopped(port)) + arc_serial_tx_chars(port); + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + } + + return IRQ_HANDLED; +@@ -366,7 +366,7 @@ arc_serial_set_termios(struct uart_port + uartl = hw_val & 0xFF; + uarth = (hw_val >> 8) & 0xFF; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + UART_ALL_IRQ_DISABLE(port); + +@@ -391,7 +391,7 @@ arc_serial_set_termios(struct uart_port + + uart_update_timeout(port, new->c_cflag, baud); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *arc_serial_type(struct uart_port *port) +@@ -521,9 +521,9 @@ static void arc_serial_console_write(str + struct uart_port *port = &arc_uart_ports[co->index].port; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + uart_console_write(port, s, count, arc_serial_console_putchar); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static struct console arc_console = { |