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Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/0023-serial-cpm_uart-Use-port-lock-wrappers.patch | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/debian/patches-rt/0023-serial-cpm_uart-Use-port-lock-wrappers.patch b/debian/patches-rt/0023-serial-cpm_uart-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..c3400eac9 --- /dev/null +++ b/debian/patches-rt/0023-serial-cpm_uart-Use-port-lock-wrappers.patch @@ -0,0 +1,70 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:43:40 +0206 +Subject: [PATCH 023/134] serial: cpm_uart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +Signed-off-by: John Ogness <john.ogness@linutronix.de> +Link: https://lore.kernel.org/r/20230914183831.587273-24-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + drivers/tty/serial/cpm_uart.c | 8 ++++---- + 1 file changed, 4 insertions(+), 4 deletions(-) + +--- a/drivers/tty/serial/cpm_uart.c ++++ b/drivers/tty/serial/cpm_uart.c +@@ -569,7 +569,7 @@ static void cpm_uart_set_termios(struct + if ((termios->c_cflag & CREAD) == 0) + port->read_status_mask &= ~BD_SC_EMPTY; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + if (IS_SMC(pinfo)) { + unsigned int bits = tty_get_frame_size(termios->c_cflag); +@@ -609,7 +609,7 @@ static void cpm_uart_set_termios(struct + clk_set_rate(pinfo->clk, baud); + else + cpm_setbrg(pinfo->brg - 1, baud); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *cpm_uart_type(struct uart_port *port) +@@ -1386,9 +1386,9 @@ static void cpm_uart_console_write(struc + cpm_uart_early_write(pinfo, s, count, true); + local_irq_restore(flags); + } else { +- spin_lock_irqsave(&pinfo->port.lock, flags); ++ uart_port_lock_irqsave(&pinfo->port, &flags); + cpm_uart_early_write(pinfo, s, count, true); +- spin_unlock_irqrestore(&pinfo->port.lock, flags); ++ uart_port_unlock_irqrestore(&pinfo->port, flags); + } + } + |