diff options
Diffstat (limited to 'debian/patches-rt/0010-serial-owl-Use-uart_prepare_sysrq_char-to-handle-sys.patch')
| -rw-r--r-- | debian/patches-rt/0010-serial-owl-Use-uart_prepare_sysrq_char-to-handle-sys.patch | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/debian/patches-rt/0010-serial-owl-Use-uart_prepare_sysrq_char-to-handle-sys.patch b/debian/patches-rt/0010-serial-owl-Use-uart_prepare_sysrq_char-to-handle-sys.patch new file mode 100644 index 000000000..bec90c28e --- /dev/null +++ b/debian/patches-rt/0010-serial-owl-Use-uart_prepare_sysrq_char-to-handle-sys.patch @@ -0,0 +1,104 @@ +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Fri, 1 Mar 2024 22:45:23 +0100 +Subject: [PATCH 10/18] serial: owl: Use uart_prepare_sysrq_char() to handle + sysrq. +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit +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. + +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 +Link: https://lore.kernel.org/r/20240301215246.891055-11-bigeasy@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + drivers/tty/serial/owl-uart.c | 30 ++++++++++++------------------ + 1 file changed, 12 insertions(+), 18 deletions(-) + +--- a/drivers/tty/serial/owl-uart.c ++++ b/drivers/tty/serial/owl-uart.c +@@ -199,6 +199,7 @@ static void owl_uart_receive_chars(struc + 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(struc + 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(struc + 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, + 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 u + { + 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 u + 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, |