diff options
Diffstat (limited to 'debian/patches-rt/0034-serial-ma35d1-Use-port-lock-wrappers.patch')
| -rw-r--r-- | debian/patches-rt/0034-serial-ma35d1-Use-port-lock-wrappers.patch | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/debian/patches-rt/0034-serial-ma35d1-Use-port-lock-wrappers.patch b/debian/patches-rt/0034-serial-ma35d1-Use-port-lock-wrappers.patch new file mode 100644 index 0000000000..995bad9aad --- /dev/null +++ b/debian/patches-rt/0034-serial-ma35d1-Use-port-lock-wrappers.patch @@ -0,0 +1,117 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:43:51 +0206 +Subject: [PATCH 034/134] serial: ma35d1: 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/20230914183831.587273-35-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/ma35d1_serial.c | 22 +++++++++++----------- + 1 file changed, 11 insertions(+), 11 deletions(-) + +--- a/drivers/tty/serial/ma35d1_serial.c ++++ b/drivers/tty/serial/ma35d1_serial.c +@@ -269,16 +269,16 @@ static void receive_chars(struct uart_ma + if (uart_handle_sysrq_char(&up->port, ch)) + continue; + +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + uart_insert_char(&up->port, fsr, MA35_FSR_RX_OVER_IF, ch, flag); +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + + fsr = serial_in(up, MA35_FSR_REG); + } while (!(fsr & MA35_FSR_RX_EMPTY) && (max_count-- > 0)); + +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + tty_flip_buffer_push(&up->port.state->port); +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + } + + static irqreturn_t ma35d1serial_interrupt(int irq, void *dev_id) +@@ -364,14 +364,14 @@ static void ma35d1serial_break_ctl(struc + unsigned long flags; + u32 lcr; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + lcr = serial_in(up, MA35_LCR_REG); + if (break_state != 0) + lcr |= MA35_LCR_BREAK; + else + lcr &= ~MA35_LCR_BREAK; + serial_out(up, MA35_LCR_REG, lcr); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static int ma35d1serial_startup(struct uart_port *port) +@@ -441,7 +441,7 @@ static void ma35d1serial_set_termios(str + * Ok, we're now changing the port state. Do it with + * interrupts disabled. + */ +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + up->port.read_status_mask = MA35_FSR_RX_OVER_IF; + if (termios->c_iflag & INPCK) +@@ -475,7 +475,7 @@ static void ma35d1serial_set_termios(str + + serial_out(up, MA35_LCR_REG, lcr); + +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static const char *ma35d1serial_type(struct uart_port *port) +@@ -560,9 +560,9 @@ static void ma35d1serial_console_write(s + if (up->port.sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock_irqsave(&up->port.lock, flags); ++ locked = uart_port_trylock_irqsave(&up->port, &flags); + else +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + /* + * First save the IER then disable the interrupts +@@ -576,7 +576,7 @@ static void ma35d1serial_console_write(s + serial_out(up, MA35_IER_REG, ier); + + if (locked) +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static int __init ma35d1serial_console_setup(struct console *co, char *options) |