diff options
| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2024-03-01 22:45:23 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-03-02 22:06:21 +0100 |
| commit | 2af521486761f6f40ff00faa0cd3d52465dfd461 (patch) | |
| tree | 328325c38ebef0bc90cc7abf0174cad8f63e553b /drivers/tty | |
| parent | 6ba52968601ad3851d0b1da7dbe227b47a7dc918 (diff) | |
serial: owl: Use uart_prepare_sysrq_char() to handle sysrq.
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.
Handle sysrq requests sysrq once the port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.
Cc: Andreas Färber <afaerber@suse.de>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-actions@lists.infradead.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-11-bigeasy@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/owl-uart.c | 30 |
1 files changed, 12 insertions, 18 deletions
diff --git a/drivers/tty/serial/owl-uart.c b/drivers/tty/serial/owl-uart.c index d9fe85397741..8b60ac0ad7cd 100644 --- a/drivers/tty/serial/owl-uart.c +++ b/drivers/tty/serial/owl-uart.c @@ -199,6 +199,7 @@ static void owl_uart_receive_chars(struct uart_port *port) stat = owl_uart_read(port, OWL_UART_STAT); while (!(stat & OWL_UART_STAT_RFEM)) { char flag = TTY_NORMAL; + bool sysrq; if (stat & OWL_UART_STAT_RXER) port->icount.overrun++; @@ -217,7 +218,9 @@ static void owl_uart_receive_chars(struct uart_port *port) val = owl_uart_read(port, OWL_UART_RXDAT); val &= 0xff; - if ((stat & port->ignore_status_mask) == 0) + sysrq = uart_prepare_sysrq_char(port, val); + + if (!sysrq && (stat & port->ignore_status_mask) == 0) tty_insert_flip_char(&port->state->port, val, flag); stat = owl_uart_read(port, OWL_UART_STAT); @@ -229,10 +232,9 @@ static void owl_uart_receive_chars(struct uart_port *port) static irqreturn_t owl_uart_irq(int irq, void *dev_id) { struct uart_port *port = dev_id; - unsigned long flags; u32 stat; - uart_port_lock_irqsave(port, &flags); + uart_port_lock(port); stat = owl_uart_read(port, OWL_UART_STAT); @@ -246,7 +248,7 @@ static irqreturn_t owl_uart_irq(int irq, void *dev_id) stat |= OWL_UART_STAT_RIP | OWL_UART_STAT_TIP; owl_uart_write(port, stat, OWL_UART_STAT); - uart_port_unlock_irqrestore(port, flags); + uart_unlock_and_check_sysrq(port); return IRQ_HANDLED; } @@ -508,18 +510,12 @@ static void owl_uart_port_write(struct uart_port *port, const char *s, { u32 old_ctl, val; unsigned long flags; - int locked; + int locked = 1; - local_irq_save(flags); - - if (port->sysrq) - locked = 0; - else if (oops_in_progress) - locked = uart_port_trylock(port); - else { - uart_port_lock(port); - locked = 1; - } + if (oops_in_progress) + locked = uart_port_trylock_irqsave(port, &flags); + else + uart_port_lock_irqsave(port, &flags); old_ctl = owl_uart_read(port, OWL_UART_CTL); val = old_ctl | OWL_UART_CTL_TRFS_TX; @@ -541,9 +537,7 @@ static void owl_uart_port_write(struct uart_port *port, const char *s, owl_uart_write(port, old_ctl, OWL_UART_CTL); if (locked) - uart_port_unlock(port); - - local_irq_restore(flags); + uart_port_unlock_irqrestore(port, flags); } static void owl_uart_console_write(struct console *co, const char *s, |