| Message ID | 20230914183831.587273-25-john.ogness@linutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | None | expand |
Hi John, On Thu, Sep 14 2023, John Ogness wrote: > From: Thomas Gleixner <tglx@linutronix.de> > > 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> Acked-by: Baruch Siach <baruch@tkos.co.il> Thanks, baruch > --- > drivers/tty/serial/digicolor-usart.c | 18 +++++++++--------- > 1 file changed, 9 insertions(+), 9 deletions(-) > > diff --git a/drivers/tty/serial/digicolor-usart.c b/drivers/tty/serial/digicolor-usart.c > index 128b5479e813..5004125f3045 100644 > --- a/drivers/tty/serial/digicolor-usart.c > +++ b/drivers/tty/serial/digicolor-usart.c > @@ -133,7 +133,7 @@ static void digicolor_uart_rx(struct uart_port *port) > { > unsigned long flags; > > - spin_lock_irqsave(&port->lock, flags); > + uart_port_lock_irqsave(port, &flags); > > while (1) { > u8 status, ch, ch_flag; > @@ -172,7 +172,7 @@ static void digicolor_uart_rx(struct uart_port *port) > ch_flag); > } > > - spin_unlock_irqrestore(&port->lock, flags); > + uart_port_unlock_irqrestore(port, flags); > > tty_flip_buffer_push(&port->state->port); > } > @@ -185,7 +185,7 @@ static void digicolor_uart_tx(struct uart_port *port) > if (digicolor_uart_tx_full(port)) > return; > > - spin_lock_irqsave(&port->lock, flags); > + uart_port_lock_irqsave(port, &flags); > > if (port->x_char) { > writeb_relaxed(port->x_char, port->membase + UA_EMI_REC); > @@ -211,7 +211,7 @@ static void digicolor_uart_tx(struct uart_port *port) > uart_write_wakeup(port); > > out: > - spin_unlock_irqrestore(&port->lock, flags); > + uart_port_unlock_irqrestore(port, flags); > } > > static irqreturn_t digicolor_uart_int(int irq, void *dev_id) > @@ -333,7 +333,7 @@ static void digicolor_uart_set_termios(struct uart_port *port, > port->ignore_status_mask |= UA_STATUS_OVERRUN_ERR > | UA_STATUS_PARITY_ERR | UA_STATUS_FRAME_ERR; > > - spin_lock_irqsave(&port->lock, flags); > + uart_port_lock_irqsave(port, &flags); > > uart_update_timeout(port, termios->c_cflag, baud); > > @@ -341,7 +341,7 @@ static void digicolor_uart_set_termios(struct uart_port *port, > writeb_relaxed(divisor & 0xff, port->membase + UA_HBAUD_LO); > writeb_relaxed(divisor >> 8, port->membase + UA_HBAUD_HI); > > - spin_unlock_irqrestore(&port->lock, flags); > + uart_port_unlock_irqrestore(port, flags); > } > > static const char *digicolor_uart_type(struct uart_port *port) > @@ -398,14 +398,14 @@ static void digicolor_uart_console_write(struct console *co, const char *c, > int locked = 1; > > if (oops_in_progress) > - locked = spin_trylock_irqsave(&port->lock, flags); > + locked = uart_port_trylock_irqsave(port, &flags); > else > - spin_lock_irqsave(&port->lock, flags); > + uart_port_lock_irqsave(port, &flags); > > uart_console_write(port, c, n, digicolor_uart_console_putchar); > > if (locked) > - spin_unlock_irqrestore(&port->lock, flags); > + uart_port_unlock_irqrestore(port, flags); > > /* Wait for transmitter to become empty */ > do {
diff --git a/drivers/tty/serial/digicolor-usart.c b/drivers/tty/serial/digicolor-usart.c index 128b5479e813..5004125f3045 100644 --- a/drivers/tty/serial/digicolor-usart.c +++ b/drivers/tty/serial/digicolor-usart.c @@ -133,7 +133,7 @@ static void digicolor_uart_rx(struct uart_port *port) { unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); while (1) { u8 status, ch, ch_flag; @@ -172,7 +172,7 @@ static void digicolor_uart_rx(struct uart_port *port) ch_flag); } - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); tty_flip_buffer_push(&port->state->port); } @@ -185,7 +185,7 @@ static void digicolor_uart_tx(struct uart_port *port) if (digicolor_uart_tx_full(port)) return; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); if (port->x_char) { writeb_relaxed(port->x_char, port->membase + UA_EMI_REC); @@ -211,7 +211,7 @@ static void digicolor_uart_tx(struct uart_port *port) uart_write_wakeup(port); out: - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static irqreturn_t digicolor_uart_int(int irq, void *dev_id) @@ -333,7 +333,7 @@ static void digicolor_uart_set_termios(struct uart_port *port, port->ignore_status_mask |= UA_STATUS_OVERRUN_ERR | UA_STATUS_PARITY_ERR | UA_STATUS_FRAME_ERR; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); uart_update_timeout(port, termios->c_cflag, baud); @@ -341,7 +341,7 @@ static void digicolor_uart_set_termios(struct uart_port *port, writeb_relaxed(divisor & 0xff, port->membase + UA_HBAUD_LO); writeb_relaxed(divisor >> 8, port->membase + UA_HBAUD_HI); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static const char *digicolor_uart_type(struct uart_port *port) @@ -398,14 +398,14 @@ static void digicolor_uart_console_write(struct console *co, const char *c, int locked = 1; if (oops_in_progress) - locked = spin_trylock_irqsave(&port->lock, flags); + locked = uart_port_trylock_irqsave(port, &flags); else - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); uart_console_write(port, c, n, digicolor_uart_console_putchar); if (locked) - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); /* Wait for transmitter to become empty */ do {