diff options
Diffstat (limited to 'debian/patches-rt/0011-serial-rda-Use-uart_prepare_sysrq_char-to-handle-sys.patch')
| -rw-r--r-- | debian/patches-rt/0011-serial-rda-Use-uart_prepare_sysrq_char-to-handle-sys.patch | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/debian/patches-rt/0011-serial-rda-Use-uart_prepare_sysrq_char-to-handle-sys.patch b/debian/patches-rt/0011-serial-rda-Use-uart_prepare_sysrq_char-to-handle-sys.patch new file mode 100644 index 000000000..35d33ed2f --- /dev/null +++ b/debian/patches-rt/0011-serial-rda-Use-uart_prepare_sysrq_char-to-handle-sys.patch @@ -0,0 +1,91 @@ +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Fri, 1 Mar 2024 22:45:24 +0100 +Subject: [PATCH 11/18] serial: rda: Use uart_prepare_sysrq_char() to handle + sysrq. +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: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> +Cc: linux-arm-kernel@lists.infradead.org +Cc: linux-unisoc@lists.infradead.org +Link: https://lore.kernel.org/r/20240301215246.891055-12-bigeasy@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + drivers/tty/serial/rda-uart.c | 28 ++++++++++------------------ + 1 file changed, 10 insertions(+), 18 deletions(-) + +--- a/drivers/tty/serial/rda-uart.c ++++ b/drivers/tty/serial/rda-uart.c +@@ -394,7 +394,8 @@ static void rda_uart_receive_chars(struc + val &= 0xff; + + port->icount.rx++; +- tty_insert_flip_char(&port->state->port, val, flag); ++ if (!uart_prepare_sysrq_char(port, val)) ++ tty_insert_flip_char(&port->state->port, val, flag); + + status = rda_uart_read(port, RDA_UART_STATUS); + } +@@ -405,10 +406,9 @@ static void rda_uart_receive_chars(struc + static irqreturn_t rda_interrupt(int irq, void *dev_id) + { + struct uart_port *port = dev_id; +- unsigned long flags; + u32 val, irq_mask; + +- uart_port_lock_irqsave(port, &flags); ++ uart_port_lock(port); + + /* Clear IRQ cause */ + val = rda_uart_read(port, RDA_UART_IRQ_CAUSE); +@@ -425,7 +425,7 @@ static irqreturn_t rda_interrupt(int irq + rda_uart_send_chars(port); + } + +- uart_port_unlock_irqrestore(port, flags); ++ uart_unlock_and_check_sysrq(port); + + return IRQ_HANDLED; + } +@@ -590,18 +590,12 @@ static void rda_uart_port_write(struct u + { + u32 old_irq_mask; + 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_irq_mask = rda_uart_read(port, RDA_UART_IRQ_MASK); + rda_uart_write(port, 0, RDA_UART_IRQ_MASK); +@@ -615,9 +609,7 @@ static void rda_uart_port_write(struct u + rda_uart_write(port, old_irq_mask, RDA_UART_IRQ_MASK); + + if (locked) +- uart_port_unlock(port); +- +- local_irq_restore(flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void rda_uart_console_write(struct console *co, const char *s, |