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Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/0054-serial-sb1250-duart-Use-port-lock-wrappers.patch | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/debian/patches-rt/0054-serial-sb1250-duart-Use-port-lock-wrappers.patch b/debian/patches-rt/0054-serial-sb1250-duart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..e5aeb528f --- /dev/null +++ b/debian/patches-rt/0054-serial-sb1250-duart-Use-port-lock-wrappers.patch @@ -0,0 +1,85 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:44:11 +0206 +Subject: [PATCH 054/134] serial: sb1250-duart: 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/20230914183831.587273-55-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/sb1250-duart.c | 12 ++++++------ + 1 file changed, 6 insertions(+), 6 deletions(-) + +--- a/drivers/tty/serial/sb1250-duart.c ++++ b/drivers/tty/serial/sb1250-duart.c +@@ -610,7 +610,7 @@ static void sbd_set_termios(struct uart_ + else + aux &= ~M_DUART_CTS_CHNG_ENA; + +- spin_lock(&uport->lock); ++ uart_port_lock(uport); + + if (sport->tx_stopped) + command |= M_DUART_TX_DIS; +@@ -632,7 +632,7 @@ static void sbd_set_termios(struct uart_ + + write_sbdchn(sport, R_DUART_CMD, command); + +- spin_unlock(&uport->lock); ++ uart_port_unlock(uport); + } + + +@@ -839,22 +839,22 @@ static void sbd_console_write(struct con + unsigned int mask; + + /* Disable transmit interrupts and enable the transmitter. */ +- spin_lock_irqsave(&uport->lock, flags); ++ uart_port_lock_irqsave(uport, &flags); + mask = read_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2)); + write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2), + mask & ~M_DUART_IMR_TX); + write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_EN); +- spin_unlock_irqrestore(&uport->lock, flags); ++ uart_port_unlock_irqrestore(uport, flags); + + uart_console_write(&sport->port, s, count, sbd_console_putchar); + + /* Restore transmit interrupts and the transmitter enable. */ +- spin_lock_irqsave(&uport->lock, flags); ++ uart_port_lock_irqsave(uport, &flags); + sbd_line_drain(sport); + if (sport->tx_stopped) + write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_DIS); + write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2), mask); +- spin_unlock_irqrestore(&uport->lock, flags); ++ uart_port_unlock_irqrestore(uport, flags); + } + + static int __init sbd_console_setup(struct console *co, char *options) |