diff options
Diffstat (limited to 'debian/patches-rt/0042-serial-mvebu-uart-Use-port-lock-wrappers.patch')
| -rw-r--r-- | debian/patches-rt/0042-serial-mvebu-uart-Use-port-lock-wrappers.patch | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/debian/patches-rt/0042-serial-mvebu-uart-Use-port-lock-wrappers.patch b/debian/patches-rt/0042-serial-mvebu-uart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..28b2c3b46 --- /dev/null +++ b/debian/patches-rt/0042-serial-mvebu-uart-Use-port-lock-wrappers.patch @@ -0,0 +1,108 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:43:59 +0206 +Subject: [PATCH 042/134] serial: mvebu-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/20230914183831.587273-43-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/mvebu-uart.c | 18 +++++++++--------- + 1 file changed, 9 insertions(+), 9 deletions(-) + +--- a/drivers/tty/serial/mvebu-uart.c ++++ b/drivers/tty/serial/mvebu-uart.c +@@ -187,9 +187,9 @@ static unsigned int mvebu_uart_tx_empty( + unsigned long flags; + unsigned int st; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + st = readl(port->membase + UART_STAT); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return (st & STAT_TX_EMP) ? TIOCSER_TEMT : 0; + } +@@ -249,14 +249,14 @@ static void mvebu_uart_break_ctl(struct + unsigned int ctl; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + ctl = readl(port->membase + UART_CTRL(port)); + if (brk == -1) + ctl |= CTRL_SND_BRK_SEQ; + else + ctl &= ~CTRL_SND_BRK_SEQ; + writel(ctl, port->membase + UART_CTRL(port)); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void mvebu_uart_rx_chars(struct uart_port *port, unsigned int status) +@@ -540,7 +540,7 @@ static void mvebu_uart_set_termios(struc + unsigned long flags; + unsigned int baud, min_baud, max_baud; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + port->read_status_mask = STAT_RX_RDY(port) | STAT_OVR_ERR | + STAT_TX_RDY(port) | STAT_TX_FIFO_FUL; +@@ -589,7 +589,7 @@ static void mvebu_uart_set_termios(struc + uart_update_timeout(port, termios->c_cflag, baud); + } + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *mvebu_uart_type(struct uart_port *port) +@@ -735,9 +735,9 @@ static void mvebu_uart_console_write(str + 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); + + ier = readl(port->membase + UART_CTRL(port)) & CTRL_BRK_INT; + intr = readl(port->membase + UART_INTR(port)) & +@@ -758,7 +758,7 @@ static void mvebu_uart_console_write(str + } + + if (locked) +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int mvebu_uart_console_setup(struct console *co, char *options) |