[PATCH tty v1 20/74] serial: arc_uart: Use port lock wrappers
From: Thomas Gleixner
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
---
drivers/tty/serial/arc_uart.c | 16
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/tty/serial/arc_uart.c b/drivers/tty/serial/arc_uart.c
index ad4ae19b6ce3..1aa5b2b49c26 100644
--- a/drivers/tty/serial/arc_uart.c
+++ b/drivers/tty/serial/arc_uart.c
@@ -279,9 +279,9 @@ static irqreturn_t arc_serial_isr(int irq, void *dev_id)
if (status & RXIENB) {
/* already in ISR, no need of xx_irqsave */
- spin_lock(&port->lock);
+ uart_port_lock(port);
arc_serial_rx_chars(port, status);
- spin_unlock(&port->lock);
+ uart_port_unlock(port);
}
if ((status & TXIENB) && (status & TXEMPTY)) {
@@ -291,12 +291,12 @@ static irqreturn_t arc_serial_isr(int irq, void *dev_id)
*/
UART_TX_IRQ_DISABLE(port);
- spin_lock(&port->lock);
+ uart_port_lock(port);
if (!uart_tx_stopped(port))
arc_serial_tx_chars(port);
- spin_unlock(&port->lock);
+ uart_port_unlock(port);
}
return IRQ_HANDLED;
@@ -366,7 +366,7 @@ arc_serial_set_termios(struct uart_port *port, struct
ktermios *new,
uartl = hw_val & 0xFF;
uarth = (hw_val >> 8) & 0xFF;
- spin_lock_irqsave(&port->lock, flags);
+ uart_port_lock_irqsave(port, &flags);
UART_ALL_IRQ_DISABLE(port);
@@ -391,7 +391,7 @@ arc_serial_set_termios(struct uart_port *port, struct
ktermios *new,
uart_update_timeout(port, new->c_cflag, baud);
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);
}
static const char *arc_serial_type(struct uart_port *port)
@@ -521,9 +521,9 @@ static void arc_serial_console_write(struct console *co,
const char *s,
struct uart_port *port = &arc_uart_ports[co->index].port;
unsigned long flags;
- spin_lock_irqsave(&port->lock, flags);
+ uart_port_lock_irqsave(port, &flags);
uart_console_write(port, s, count, arc_serial_console_putchar);
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);
}
static struct console arc_console = {
--
2.39.2
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[PATCH tty v1 00/74] serial: wrappers for uart port lock
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. Provide and use wrapper functions for spin_[un]lock*(port->lock) invocations so that the console mechanics can be applied later on at a single place and does not require to copy the same logic all over the drivers. Patch 1 adds the wrapper functions. Patches 2-74 switch all uart port locking call sites to use the new wrappers. These patches were automatically generated using coccinelle. The 2 used coccinelle scripts are included below and executed as follows: $ spatch --sp-file uartlock-1.cocci $FILE $ spatch --sp-file uartlock-2.cocci --recursive-includes $FILE This series brings no functional change. Patches 2-74 contain identical commit message bodies. Feel free to fold them into a single commit if that seems more reasonable. Thomas Gleixner (74): serial: core: Provide port lock wrappers serial: core: Use lock wrappers serial: 21285: Use port lock wrappers serial: 8250_aspeed_vuart: Use port lock wrappers serial: 8250_bcm7271: Use port lock wrappers serial: 8250: Use port lock wrappers serial: 8250_dma: Use port lock wrappers serial: 8250_dw: Use port lock wrappers serial: 8250_exar: Use port lock wrappers serial: 8250_fsl: Use port lock wrappers serial: 8250_mtk: Use port lock wrappers serial: 8250_omap: Use port lock wrappers serial: 8250_pci1: Use port lock wrappers serial: altera_jtaguart: Use port lock wrappers serial: altera_uart: Use port lock wrappers serial: amba-pl010: Use port lock wrappers serial: amba-pl011: Use port lock wrappers serial: apb: Use port lock wrappers serial: ar933x: Use port lock wrappers serial: arc_uart: Use port lock wrappers serial: atmel: Use port lock wrappers serial: bcm63xx-uart: Use port lock wrappers serial: cpm_uart: Use port lock wrappers serial: digicolor: Use port lock wrappers serial: dz: Use port lock wrappers serial: linflexuart: Use port lock wrappers serial: fsl_lpuart: Use port lock wrappers serial: icom: Use port lock wrappers serial: imx: Use port lock wrappers serial: ip22zilog: Use port lock wrappers serial: jsm: Use port lock wrappers serial: liteuart: Use port lock wrappers serial: lpc32xx_hs: Use port lock wrappers serial: ma35d1: Use port lock wrappers serial: mcf: Use port lock wrappers serial: men_z135_uart: Use port lock wrappers serial: meson: Use port lock wrappers serial: milbeaut_usio: Use port lock wrappers serial: mpc52xx: Use port lock wrappers serial: mps2-uart: Use port lock wrappers serial: msm: Use port lock wrappers serial: mvebu-uart: Use port lock wrappers serial: omap: Use port lock wrappers serial: owl: Use port lock wrappers serial: pch: Use port lock wrappers serial: pic32: Use port lock wrappers serial: pmac_zilog: Use port lock wrappers serial: pxa: Use port lock wrappers serial: qcom-geni: Use port lock wrappers serial: rda: Use port lock wrappers serial: rp2: Use port lock wrappers serial: sa1100: Use port lock wrappers serial: samsung_tty: Use port lock wrappers serial: sb1250-duart: Use port lock wrappers serial: sc16is7xx: Use port lock wrappers serial: tegra: Use port lock wrappers serial: core: Use port lock wrappers serial: mctrl_gpio: Use port lock wrappers serial: txx9: Use port lock wrappers serial: sh-sci: Use port lock wrappers serial: sifive: Use port lock wrappers serial: sprd: Use port lock wrappers serial: st-asc: Use port lock wrappers serial: stm32: Use port lock wrappers serial: sunhv: Use port lock wrappers serial: sunplus-uart: Use port lock wrappers serial: sunsab: Use port lock wrappers serial: sunsu: Use port lock wrappers serial: sunzilog: Use port lock wrappers serial: timbuart: Use port lock wrappers serial: uartlite: Use port lock wrappers serial: ucc_uart: Use port lock wrappers serial: vt8500: Use port lock wrappers serial: xilinx_uartps: Use port lock wrappers drivers/tty/serial/21285.c | 8 +- drivers/tty/serial/8250/8250_aspeed_vuart.c | 6 +- drivers/tty/serial/8250/8250_bcm7271.c | 28 +++--- drivers/tty/serial/8250/8250_core.c | 12 +-- drivers/tty/serial/8250/8250_dma.c |
Re: [PATCH tty v1 00/74] serial: wrappers for uart port lock
On Thu, 14 Sep 2023, John Ogness wrote: > Patches 2-74 switch all uart port locking call sites to use the new > wrappers. These patches were automatically generated using coccinelle. Hmm, no need to do this for drivers/tty/serial/zs.c? Maciej ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
