diff options
Diffstat (limited to 'debian/patches-rt/0061-serial-sifive-Use-port-lock-wrappers.patch')
| -rw-r--r-- | debian/patches-rt/0061-serial-sifive-Use-port-lock-wrappers.patch | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/debian/patches-rt/0061-serial-sifive-Use-port-lock-wrappers.patch b/debian/patches-rt/0061-serial-sifive-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..a2babdbea --- /dev/null +++ b/debian/patches-rt/0061-serial-sifive-Use-port-lock-wrappers.patch @@ -0,0 +1,102 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:44:18 +0206 +Subject: [PATCH 061/134] serial: sifive: 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/20230914183831.587273-62-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/sifive.c | 16 ++++++++-------- + 1 file changed, 8 insertions(+), 8 deletions(-) + +--- a/drivers/tty/serial/sifive.c ++++ b/drivers/tty/serial/sifive.c +@@ -521,11 +521,11 @@ static irqreturn_t sifive_serial_irq(int + struct sifive_serial_port *ssp = dev_id; + u32 ip; + +- spin_lock(&ssp->port.lock); ++ uart_port_lock(&ssp->port); + + ip = __ssp_readl(ssp, SIFIVE_SERIAL_IP_OFFS); + if (!ip) { +- spin_unlock(&ssp->port.lock); ++ uart_port_unlock(&ssp->port); + return IRQ_NONE; + } + +@@ -534,7 +534,7 @@ static irqreturn_t sifive_serial_irq(int + if (ip & SIFIVE_SERIAL_IP_TXWM_MASK) + __ssp_transmit_chars(ssp); + +- spin_unlock(&ssp->port.lock); ++ uart_port_unlock(&ssp->port); + + return IRQ_HANDLED; + } +@@ -653,7 +653,7 @@ static void sifive_serial_set_termios(st + ssp->port.uartclk / 16); + __ssp_update_baud_rate(ssp, rate); + +- spin_lock_irqsave(&ssp->port.lock, flags); ++ uart_port_lock_irqsave(&ssp->port, &flags); + + /* Update the per-port timeout */ + uart_update_timeout(port, termios->c_cflag, rate); +@@ -670,7 +670,7 @@ static void sifive_serial_set_termios(st + if (v != old_v) + __ssp_writel(v, SIFIVE_SERIAL_RXCTRL_OFFS, ssp); + +- spin_unlock_irqrestore(&ssp->port.lock, flags); ++ uart_port_unlock_irqrestore(&ssp->port, flags); + } + + static void sifive_serial_release_port(struct uart_port *port) +@@ -795,9 +795,9 @@ static void sifive_serial_console_write( + if (ssp->port.sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock(&ssp->port.lock); ++ locked = uart_port_trylock(&ssp->port); + else +- spin_lock(&ssp->port.lock); ++ uart_port_lock(&ssp->port); + + ier = __ssp_readl(ssp, SIFIVE_SERIAL_IE_OFFS); + __ssp_writel(0, SIFIVE_SERIAL_IE_OFFS, ssp); +@@ -807,7 +807,7 @@ static void sifive_serial_console_write( + __ssp_writel(ier, SIFIVE_SERIAL_IE_OFFS, ssp); + + if (locked) +- spin_unlock(&ssp->port.lock); ++ uart_port_unlock(&ssp->port); + local_irq_restore(flags); + } + |