From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx> --- drivers/tty/serial/pic32_uart.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/drivers/tty/serial/pic32_uart.c b/drivers/tty/serial/pic32_uart.c index e308d5022b3f..3a95bf5d55d3 100644 --- a/drivers/tty/serial/pic32_uart.c +++ b/drivers/tty/serial/pic32_uart.c @@ -243,7 +243,7 @@ static void pic32_uart_break_ctl(struct uart_port *port, int ctl) struct pic32_sport *sport = to_pic32_sport(port); unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); if (ctl) pic32_uart_writel(sport, PIC32_SET(PIC32_UART_STA), @@ -252,7 +252,7 @@ static void pic32_uart_break_ctl(struct uart_port *port, int ctl) pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_STA), PIC32_UART_STA_UTXBRK); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } /* get port type in string format */ @@ -274,7 +274,7 @@ static void pic32_uart_do_rx(struct uart_port *port) */ max_count = PIC32_UART_RX_FIFO_DEPTH; - spin_lock(&port->lock); + uart_port_lock(port); tty = &port->state->port; @@ -331,7 +331,7 @@ static void pic32_uart_do_rx(struct uart_port *port) } while (--max_count); - spin_unlock(&port->lock); + uart_port_unlock(port); tty_flip_buffer_push(tty); } @@ -410,9 +410,9 @@ static irqreturn_t pic32_uart_tx_interrupt(int irq, void *dev_id) struct uart_port *port = dev_id; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); pic32_uart_do_tx(port); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); return IRQ_HANDLED; } @@ -580,9 +580,9 @@ static void pic32_uart_shutdown(struct uart_port *port) unsigned long flags; /* disable uart */ - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); pic32_uart_dsbl_and_mask(port); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); clk_disable_unprepare(sport->clk); /* free all 3 interrupts for this UART */ @@ -604,7 +604,7 @@ static void pic32_uart_set_termios(struct uart_port *port, unsigned int quot; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* disable uart and mask all interrupts while changing speed */ pic32_uart_dsbl_and_mask(port); @@ -672,7 +672,7 @@ static void pic32_uart_set_termios(struct uart_port *port, /* enable uart */ pic32_uart_en_and_unmask(port); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } /* serial core request to claim uart iomem */ -- 2.39.2
