diff options
Diffstat (limited to 'debian/patches-rt/0071-serial-uartlite-Use-port-lock-wrappers.patch')
| -rw-r--r-- | debian/patches-rt/0071-serial-uartlite-Use-port-lock-wrappers.patch | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/debian/patches-rt/0071-serial-uartlite-Use-port-lock-wrappers.patch b/debian/patches-rt/0071-serial-uartlite-Use-port-lock-wrappers.patch new file mode 100644 index 0000000000..13c64d7eed --- /dev/null +++ b/debian/patches-rt/0071-serial-uartlite-Use-port-lock-wrappers.patch @@ -0,0 +1,105 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:44:28 +0206 +Subject: [PATCH 071/134] serial: uartlite: 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/20230914183831.587273-72-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/uartlite.c | 18 +++++++++--------- + 1 file changed, 9 insertions(+), 9 deletions(-) + +--- a/drivers/tty/serial/uartlite.c ++++ b/drivers/tty/serial/uartlite.c +@@ -216,11 +216,11 @@ static irqreturn_t ulite_isr(int irq, vo + unsigned long flags; + + do { +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + stat = uart_in32(ULITE_STATUS, port); + busy = ulite_receive(port, stat); + busy |= ulite_transmit(port, stat); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + n++; + } while (busy); + +@@ -238,9 +238,9 @@ static unsigned int ulite_tx_empty(struc + unsigned long flags; + unsigned int ret; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + ret = uart_in32(ULITE_STATUS, port); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return ret & ULITE_STATUS_TXEMPTY ? TIOCSER_TEMT : 0; + } +@@ -323,7 +323,7 @@ static void ulite_set_termios(struct uar + termios->c_cflag |= pdata->cflags & (PARENB | PARODD | CSIZE); + tty_termios_encode_baud_rate(termios, pdata->baud, pdata->baud); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + port->read_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN + | ULITE_STATUS_TXFULL; +@@ -346,7 +346,7 @@ static void ulite_set_termios(struct uar + /* update timeout */ + uart_update_timeout(port, termios->c_cflag, pdata->baud); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *ulite_type(struct uart_port *port) +@@ -495,9 +495,9 @@ static void ulite_console_write(struct c + int locked = 1; + + if (oops_in_progress) { +- locked = spin_trylock_irqsave(&port->lock, flags); ++ locked = uart_port_trylock_irqsave(port, &flags); + } else +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* save and disable interrupt */ + ier = uart_in32(ULITE_STATUS, port) & ULITE_STATUS_IE; +@@ -512,7 +512,7 @@ static void ulite_console_write(struct c + uart_out32(ULITE_CONTROL_IE, ULITE_CONTROL, port); + + if (locked) +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int ulite_console_setup(struct console *co, char *options) |