diff options
Diffstat (limited to 'debian/patches-rt/0009-serial-lpc32xx_hs-Use-uart_prepare_sysrq_char-to-han.patch')
| -rw-r--r-- | debian/patches-rt/0009-serial-lpc32xx_hs-Use-uart_prepare_sysrq_char-to-han.patch | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/debian/patches-rt/0009-serial-lpc32xx_hs-Use-uart_prepare_sysrq_char-to-han.patch b/debian/patches-rt/0009-serial-lpc32xx_hs-Use-uart_prepare_sysrq_char-to-han.patch new file mode 100644 index 000000000..e099cf8e6 --- /dev/null +++ b/debian/patches-rt/0009-serial-lpc32xx_hs-Use-uart_prepare_sysrq_char-to-han.patch @@ -0,0 +1,68 @@ +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Fri, 1 Mar 2024 22:45:22 +0100 +Subject: [PATCH 09/18] serial: lpc32xx_hs: 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: Vladimir Zapolskiy <vz@mleia.com> +Cc: linux-arm-kernel@lists.infradead.org +Link: https://lore.kernel.org/r/20240301215246.891055-10-bigeasy@linutronix.de +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + drivers/tty/serial/lpc32xx_hs.c | 17 +++++++---------- + 1 file changed, 7 insertions(+), 10 deletions(-) + +--- a/drivers/tty/serial/lpc32xx_hs.c ++++ b/drivers/tty/serial/lpc32xx_hs.c +@@ -136,20 +136,16 @@ static void lpc32xx_hsuart_console_write + int locked = 1; + + touch_nmi_watchdog(); +- 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); + + uart_console_write(&up->port, s, count, lpc32xx_hsuart_console_putchar); + wait_for_xmit_empty(&up->port); + + if (locked) +- uart_port_unlock(&up->port); +- local_irq_restore(flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static int __init lpc32xx_hsuart_console_setup(struct console *co, +@@ -268,7 +264,8 @@ static void __serial_lpc32xx_rx(struct u + tty_insert_flip_char(tport, 0, TTY_FRAME); + } + +- tty_insert_flip_char(tport, (tmp & 0xFF), flag); ++ if (!uart_prepare_sysrq_char(port, tmp & 0xff)) ++ tty_insert_flip_char(tport, (tmp & 0xFF), flag); + + tmp = readl(LPC32XX_HSUART_FIFO(port->membase)); + } +@@ -333,7 +330,7 @@ static irqreturn_t serial_lpc32xx_interr + __serial_lpc32xx_tx(port); + } + +- uart_port_unlock(port); ++ uart_unlock_and_check_sysrq(port); + + return IRQ_HANDLED; + } |