diff options
Diffstat (limited to 'debian/patches-rt/0032-serial-liteuart-Use-port-lock-wrappers.patch')
| -rw-r--r-- | debian/patches-rt/0032-serial-liteuart-Use-port-lock-wrappers.patch | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/debian/patches-rt/0032-serial-liteuart-Use-port-lock-wrappers.patch b/debian/patches-rt/0032-serial-liteuart-Use-port-lock-wrappers.patch new file mode 100644 index 0000000000..ae679c098c --- /dev/null +++ b/debian/patches-rt/0032-serial-liteuart-Use-port-lock-wrappers.patch @@ -0,0 +1,110 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:43:49 +0206 +Subject: [PATCH 032/134] serial: liteuart: 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> +Acked-by: Gabriel Somlo <gsomlo@gmail.com> +Signed-off-by: John Ogness <john.ogness@linutronix.de> +Link: https://lore.kernel.org/r/20230914183831.587273-33-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/liteuart.c | 20 ++++++++++---------- + 1 file changed, 10 insertions(+), 10 deletions(-) + +--- a/drivers/tty/serial/liteuart.c ++++ b/drivers/tty/serial/liteuart.c +@@ -139,13 +139,13 @@ static irqreturn_t liteuart_interrupt(in + * if polling, the context would be "in_serving_softirq", so use + * irq[save|restore] spin_lock variants to cover all possibilities + */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + isr = litex_read8(port->membase + OFF_EV_PENDING) & uart->irq_reg; + if (isr & EV_RX) + liteuart_rx_chars(port); + if (isr & EV_TX) + liteuart_tx_chars(port); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return IRQ_RETVAL(isr); + } +@@ -195,10 +195,10 @@ static int liteuart_startup(struct uart_ + } + } + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + /* only enabling rx irqs during startup */ + liteuart_update_irq_reg(port, true, EV_RX); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + if (!port->irq) { + timer_setup(&uart->timer, liteuart_timer, 0); +@@ -213,9 +213,9 @@ static void liteuart_shutdown(struct uar + struct liteuart_port *uart = to_liteuart_port(port); + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + liteuart_update_irq_reg(port, false, EV_RX | EV_TX); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + if (port->irq) + free_irq(port->irq, port); +@@ -229,13 +229,13 @@ static void liteuart_set_termios(struct + unsigned int baud; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* update baudrate */ + baud = uart_get_baud_rate(port, new, old, 0, 460800); + uart_update_timeout(port, new->c_cflag, baud); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *liteuart_type(struct uart_port *port) +@@ -382,9 +382,9 @@ static void liteuart_console_write(struc + uart = (struct liteuart_port *)xa_load(&liteuart_array, co->index); + port = &uart->port; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + uart_console_write(port, s, count, liteuart_putchar); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int liteuart_console_setup(struct console *co, char *options) |