diff options
Diffstat (limited to 'debian/patches-rt/0012-serial-sifive-Use-uart_prepare_sysrq_char-to-handle-.patch')
| -rw-r--r-- | debian/patches-rt/0012-serial-sifive-Use-uart_prepare_sysrq_char-to-handle-.patch | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/debian/patches-rt/0012-serial-sifive-Use-uart_prepare_sysrq_char-to-handle-.patch b/debian/patches-rt/0012-serial-sifive-Use-uart_prepare_sysrq_char-to-handle-.patch new file mode 100644 index 000000000..5b82468e4 --- /dev/null +++ b/debian/patches-rt/0012-serial-sifive-Use-uart_prepare_sysrq_char-to-handle-.patch @@ -0,0 +1,71 @@ +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Fri, 1 Mar 2024 22:45:25 +0100 +Subject: [PATCH 12/18] serial: sifive: 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: Palmer Dabbelt <palmer@dabbelt.com> +Cc: Paul Walmsley <paul.walmsley@sifive.com> +Cc: linux-riscv@lists.infradead.org +Link: https://lore.kernel.org/r/20240301215246.891055-13-bigeasy@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + drivers/tty/serial/sifive.c | 17 +++++++---------- + 1 file changed, 7 insertions(+), 10 deletions(-) + +--- a/drivers/tty/serial/sifive.c ++++ b/drivers/tty/serial/sifive.c +@@ -412,7 +412,8 @@ static void __ssp_receive_chars(struct s + break; + + ssp->port.icount.rx++; +- uart_insert_char(&ssp->port, 0, 0, ch, TTY_NORMAL); ++ if (!uart_prepare_sysrq_char(&ssp->port, ch)) ++ uart_insert_char(&ssp->port, 0, 0, ch, TTY_NORMAL); + } + + tty_flip_buffer_push(&ssp->port.state->port); +@@ -534,7 +535,7 @@ static irqreturn_t sifive_serial_irq(int + if (ip & SIFIVE_SERIAL_IP_TXWM_MASK) + __ssp_transmit_chars(ssp); + +- uart_port_unlock(&ssp->port); ++ uart_unlock_and_check_sysrq(&ssp->port); + + return IRQ_HANDLED; + } +@@ -791,13 +792,10 @@ static void sifive_serial_console_write( + if (!ssp) + return; + +- local_irq_save(flags); +- if (ssp->port.sysrq) +- locked = 0; +- else if (oops_in_progress) +- locked = uart_port_trylock(&ssp->port); ++ if (oops_in_progress) ++ locked = uart_port_trylock_irqsave(&ssp->port, &flags); + else +- uart_port_lock(&ssp->port); ++ uart_port_lock_irqsave(&ssp->port, &flags); + + ier = __ssp_readl(ssp, SIFIVE_SERIAL_IE_OFFS); + __ssp_writel(0, SIFIVE_SERIAL_IE_OFFS, ssp); +@@ -807,8 +805,7 @@ static void sifive_serial_console_write( + __ssp_writel(ier, SIFIVE_SERIAL_IE_OFFS, ssp); + + if (locked) +- uart_port_unlock(&ssp->port); +- local_irq_restore(flags); ++ uart_port_unlock_irqrestore(&ssp->port, flags); + } + + static int sifive_serial_console_setup(struct console *co, char *options) |