diff options
Diffstat (limited to 'debian/patches-rt/0002-serial-ar933x-Use-uart_prepare_sysrq_char.patch')
| -rw-r--r-- | debian/patches-rt/0002-serial-ar933x-Use-uart_prepare_sysrq_char.patch | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/debian/patches-rt/0002-serial-ar933x-Use-uart_prepare_sysrq_char.patch b/debian/patches-rt/0002-serial-ar933x-Use-uart_prepare_sysrq_char.patch new file mode 100644 index 000000000..f8f97abf1 --- /dev/null +++ b/debian/patches-rt/0002-serial-ar933x-Use-uart_prepare_sysrq_char.patch @@ -0,0 +1,68 @@ +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Fri, 1 Mar 2024 22:45:15 +0100 +Subject: [PATCH 02/18] serial: ar933x: Use uart_prepare_sysrq_char(). +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.8/older/patches-6.8.2-rt11.tar.xz + +The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT. +The driver splits the locking function into two parts: local_irq_save() and +uart_port_lock() and this breaks PREEMPT_RT. + +Delay handling sysrq until port lock is dropped. +Remove the special case in the console write routine an always use the +complete locking function. + +Link: https://lore.kernel.org/r/20240301215246.891055-3-bigeasy@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + drivers/tty/serial/ar933x_uart.c | 18 ++++++------------ + 1 file changed, 6 insertions(+), 12 deletions(-) + +--- a/drivers/tty/serial/ar933x_uart.c ++++ b/drivers/tty/serial/ar933x_uart.c +@@ -378,7 +378,7 @@ static void ar933x_uart_rx_chars(struct + up->port.icount.rx++; + ch = rdata & AR933X_UART_DATA_TX_RX_MASK; + +- if (uart_handle_sysrq_char(&up->port, ch)) ++ if (uart_prepare_sysrq_char(&up->port, ch)) + continue; + + if ((up->port.ignore_status_mask & AR933X_DUMMY_STATUS_RD) == 0) +@@ -468,7 +468,7 @@ static irqreturn_t ar933x_uart_interrupt + ar933x_uart_tx_chars(up); + } + +- uart_port_unlock(&up->port); ++ uart_unlock_and_check_sysrq(&up->port); + + return IRQ_HANDLED; + } +@@ -627,14 +627,10 @@ static void ar933x_uart_console_write(st + unsigned int int_en; + int locked = 1; + +- local_irq_save(flags); +- +- if (up->port.sysrq) +- locked = 0; +- else if (oops_in_progress) +- locked = uart_port_trylock(&up->port); ++ if (oops_in_progress) ++ locked = uart_port_trylock_irqsave(&up->port, &flags); + else +- uart_port_lock(&up->port); ++ uart_port_lock_irqsave(&up->port, &flags); + + /* + * First save the IER then disable the interrupts +@@ -654,9 +650,7 @@ static void ar933x_uart_console_write(st + ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_ALLINTS); + + if (locked) +- uart_port_unlock(&up->port); +- +- local_irq_restore(flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static int ar933x_uart_console_setup(struct console *co, char *options) |