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Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/0041-serial-msm-Use-port-lock-wrappers.patch | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/debian/patches-rt/0041-serial-msm-Use-port-lock-wrappers.patch b/debian/patches-rt/0041-serial-msm-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..89b845330 --- /dev/null +++ b/debian/patches-rt/0041-serial-msm-Use-port-lock-wrappers.patch @@ -0,0 +1,185 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:43:58 +0206 +Subject: [PATCH 041/134] serial: msm: 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> +Reviewed-by: Bjorn Andersson <quic_bjorande@quicinc.com> +Signed-off-by: John Ogness <john.ogness@linutronix.de> +Link: https://lore.kernel.org/r/20230914183831.587273-42-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/msm_serial.c | 38 +++++++++++++++++++------------------- + 1 file changed, 19 insertions(+), 19 deletions(-) + +--- a/drivers/tty/serial/msm_serial.c ++++ b/drivers/tty/serial/msm_serial.c +@@ -444,7 +444,7 @@ static void msm_complete_tx_dma(void *ar + unsigned int count; + u32 val; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Already stopped */ + if (!dma->count) +@@ -476,7 +476,7 @@ static void msm_complete_tx_dma(void *ar + + msm_handle_tx(port); + done: +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int msm_handle_tx_dma(struct msm_port *msm_port, unsigned int count) +@@ -549,7 +549,7 @@ static void msm_complete_rx_dma(void *ar + unsigned long flags; + u32 val; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Already stopped */ + if (!dma->count) +@@ -587,16 +587,16 @@ static void msm_complete_rx_dma(void *ar + if (!(port->read_status_mask & MSM_UART_SR_RX_BREAK)) + flag = TTY_NORMAL; + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + sysrq = uart_handle_sysrq_char(port, dma->virt[i]); +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + if (!sysrq) + tty_insert_flip_char(tport, dma->virt[i], flag); + } + + msm_start_rx_dma(msm_port); + done: +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + if (count) + tty_flip_buffer_push(tport); +@@ -762,9 +762,9 @@ static void msm_handle_rx_dm(struct uart + if (!(port->read_status_mask & MSM_UART_SR_RX_BREAK)) + flag = TTY_NORMAL; + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + sysrq = uart_handle_sysrq_char(port, buf[i]); +- spin_lock(&port->lock); ++ uart_port_lock(port); + if (!sysrq) + tty_insert_flip_char(tport, buf[i], flag); + } +@@ -824,9 +824,9 @@ static void msm_handle_rx(struct uart_po + else if (sr & MSM_UART_SR_PAR_FRAME_ERR) + flag = TTY_FRAME; + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + sysrq = uart_handle_sysrq_char(port, c); +- spin_lock(&port->lock); ++ uart_port_lock(port); + if (!sysrq) + tty_insert_flip_char(tport, c, flag); + } +@@ -951,7 +951,7 @@ static irqreturn_t msm_uart_irq(int irq, + unsigned int misr; + u32 val; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + misr = msm_read(port, MSM_UART_MISR); + msm_write(port, 0, MSM_UART_IMR); /* disable interrupt */ + +@@ -983,7 +983,7 @@ static irqreturn_t msm_uart_irq(int irq, + msm_handle_delta_cts(port); + + msm_write(port, msm_port->imr, MSM_UART_IMR); /* restore interrupt */ +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return IRQ_HANDLED; + } +@@ -1128,13 +1128,13 @@ static int msm_set_baud_rate(struct uart + unsigned long flags, rate; + + flags = *saved_flags; +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + entry = msm_find_best_baud(port, baud, &rate); + clk_set_rate(msm_port->clk, rate); + baud = rate / 16 / entry->divisor; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + *saved_flags = flags; + port->uartclk = rate; + +@@ -1266,7 +1266,7 @@ static void msm_set_termios(struct uart_ + unsigned long flags; + unsigned int baud, mr; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + if (dma->chan) /* Terminate if any */ + msm_stop_dma(port, dma); +@@ -1338,7 +1338,7 @@ static void msm_set_termios(struct uart_ + /* Try to use DMA */ + msm_start_rx_dma(msm_port); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *msm_type(struct uart_port *port) +@@ -1620,9 +1620,9 @@ static void __msm_console_write(struct u + if (port->sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock(&port->lock); ++ locked = uart_port_trylock(port); + else +- spin_lock(&port->lock); ++ uart_port_lock(port); + + if (is_uartdm) + msm_reset_dm_count(port, count); +@@ -1661,7 +1661,7 @@ static void __msm_console_write(struct u + } + + if (locked) +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + local_irq_restore(flags); + } |