diff options
Diffstat (limited to 'debian/patches-rt/0007-serial-8250_dma-Use-port-lock-wrappers.patch')
| -rw-r--r-- | debian/patches-rt/0007-serial-8250_dma-Use-port-lock-wrappers.patch | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/debian/patches-rt/0007-serial-8250_dma-Use-port-lock-wrappers.patch b/debian/patches-rt/0007-serial-8250_dma-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..bc8686e89 --- /dev/null +++ b/debian/patches-rt/0007-serial-8250_dma-Use-port-lock-wrappers.patch @@ -0,0 +1,80 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:43:24 +0206 +Subject: [PATCH 007/134] serial: 8250_dma: Use port lock wrappers +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit +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> +Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> +Signed-off-by: John Ogness <john.ogness@linutronix.de> +Link: https://lore.kernel.org/r/20230914183831.587273-8-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/8250/8250_dma.c | 8 ++++---- + 1 file changed, 4 insertions(+), 4 deletions(-) + +--- a/drivers/tty/serial/8250/8250_dma.c ++++ b/drivers/tty/serial/8250/8250_dma.c +@@ -22,7 +22,7 @@ static void __dma_tx_complete(void *para + dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr, + UART_XMIT_SIZE, DMA_TO_DEVICE); + +- spin_lock_irqsave(&p->port.lock, flags); ++ uart_port_lock_irqsave(&p->port, &flags); + + dma->tx_running = 0; + +@@ -35,7 +35,7 @@ static void __dma_tx_complete(void *para + if (ret || !dma->tx_running) + serial8250_set_THRI(p); + +- spin_unlock_irqrestore(&p->port.lock, flags); ++ uart_port_unlock_irqrestore(&p->port, flags); + } + + static void __dma_rx_complete(struct uart_8250_port *p) +@@ -70,7 +70,7 @@ static void dma_rx_complete(void *param) + struct uart_8250_dma *dma = p->dma; + unsigned long flags; + +- spin_lock_irqsave(&p->port.lock, flags); ++ uart_port_lock_irqsave(&p->port, &flags); + if (dma->rx_running) + __dma_rx_complete(p); + +@@ -80,7 +80,7 @@ static void dma_rx_complete(void *param) + */ + if (!dma->rx_running && (serial_lsr_in(p) & UART_LSR_DR)) + p->dma->rx_dma(p); +- spin_unlock_irqrestore(&p->port.lock, flags); ++ uart_port_unlock_irqrestore(&p->port, flags); + } + + int serial8250_tx_dma(struct uart_8250_port *p) |