From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> To: linux-serial@vger.kernel.org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Jiri Slaby <jirislaby@kernel.org>, Thomas Gleixner <tglx@linutronix.de>, Sebastian Andrzej Siewior <bigeasy@linutronix.de>, Palmer Dabbelt <palmer@dabbelt.com>, Paul Walmsley <paul.walmsley@sifive.com>, linux-riscv@lists.infradead.org Subject: [PATCH 12/18] serial: sifive: Use uart_prepare_sysrq_char() to handle sysrq. Date: Fri, 1 Mar 2024 22:45:25 +0100 [thread overview] Message-ID: <20240301215246.891055-13-bigeasy@linutronix.de> (raw) In-Reply-To: <20240301215246.891055-1-bigeasy@linutronix.de> The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT. The driver splits the locking function into two parts: local_irq_save() and uart_port_lock() and this breaks PREEMPT_RT. Handle sysrq requests sysrq once the port lock is dropped. Remove the special case in the console write routine an always use the complete locking function. Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: linux-riscv@lists.infradead.org Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- drivers/tty/serial/sifive.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/drivers/tty/serial/sifive.c b/drivers/tty/serial/sifive.c index a4cc569a78a25..0670fd9f84967 100644 --- a/drivers/tty/serial/sifive.c +++ b/drivers/tty/serial/sifive.c @@ -412,7 +412,8 @@ static void __ssp_receive_chars(struct sifive_serial_port *ssp) break; ssp->port.icount.rx++; - uart_insert_char(&ssp->port, 0, 0, ch, TTY_NORMAL); + if (!uart_prepare_sysrq_char(&ssp->port, ch)) + uart_insert_char(&ssp->port, 0, 0, ch, TTY_NORMAL); } tty_flip_buffer_push(&ssp->port.state->port); @@ -534,7 +535,7 @@ static irqreturn_t sifive_serial_irq(int irq, void *dev_id) if (ip & SIFIVE_SERIAL_IP_TXWM_MASK) __ssp_transmit_chars(ssp); - uart_port_unlock(&ssp->port); + uart_unlock_and_check_sysrq(&ssp->port); return IRQ_HANDLED; } @@ -791,13 +792,10 @@ static void sifive_serial_console_write(struct console *co, const char *s, if (!ssp) return; - local_irq_save(flags); - if (ssp->port.sysrq) - locked = 0; - else if (oops_in_progress) - locked = uart_port_trylock(&ssp->port); + if (oops_in_progress) + locked = uart_port_trylock_irqsave(&ssp->port, &flags); else - uart_port_lock(&ssp->port); + uart_port_lock_irqsave(&ssp->port, &flags); ier = __ssp_readl(ssp, SIFIVE_SERIAL_IE_OFFS); __ssp_writel(0, SIFIVE_SERIAL_IE_OFFS, ssp); @@ -807,8 +805,7 @@ static void sifive_serial_console_write(struct console *co, const char *s, __ssp_writel(ier, SIFIVE_SERIAL_IE_OFFS, ssp); if (locked) - uart_port_unlock(&ssp->port); - local_irq_restore(flags); + uart_port_unlock_irqrestore(&ssp->port, flags); } static int sifive_serial_console_setup(struct console *co, char *options) -- 2.43.0
WARNING: multiple messages have this Message-ID (diff)
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> To: linux-serial@vger.kernel.org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Jiri Slaby <jirislaby@kernel.org>, Thomas Gleixner <tglx@linutronix.de>, Sebastian Andrzej Siewior <bigeasy@linutronix.de>, Palmer Dabbelt <palmer@dabbelt.com>, Paul Walmsley <paul.walmsley@sifive.com>, linux-riscv@lists.infradead.org Subject: [PATCH 12/18] serial: sifive: Use uart_prepare_sysrq_char() to handle sysrq. Date: Fri, 1 Mar 2024 22:45:25 +0100 [thread overview] Message-ID: <20240301215246.891055-13-bigeasy@linutronix.de> (raw) In-Reply-To: <20240301215246.891055-1-bigeasy@linutronix.de> The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT. The driver splits the locking function into two parts: local_irq_save() and uart_port_lock() and this breaks PREEMPT_RT. Handle sysrq requests sysrq once the port lock is dropped. Remove the special case in the console write routine an always use the complete locking function. Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: linux-riscv@lists.infradead.org Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- drivers/tty/serial/sifive.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/drivers/tty/serial/sifive.c b/drivers/tty/serial/sifive.c index a4cc569a78a25..0670fd9f84967 100644 --- a/drivers/tty/serial/sifive.c +++ b/drivers/tty/serial/sifive.c @@ -412,7 +412,8 @@ static void __ssp_receive_chars(struct sifive_serial_port *ssp) break; ssp->port.icount.rx++; - uart_insert_char(&ssp->port, 0, 0, ch, TTY_NORMAL); + if (!uart_prepare_sysrq_char(&ssp->port, ch)) + uart_insert_char(&ssp->port, 0, 0, ch, TTY_NORMAL); } tty_flip_buffer_push(&ssp->port.state->port); @@ -534,7 +535,7 @@ static irqreturn_t sifive_serial_irq(int irq, void *dev_id) if (ip & SIFIVE_SERIAL_IP_TXWM_MASK) __ssp_transmit_chars(ssp); - uart_port_unlock(&ssp->port); + uart_unlock_and_check_sysrq(&ssp->port); return IRQ_HANDLED; } @@ -791,13 +792,10 @@ static void sifive_serial_console_write(struct console *co, const char *s, if (!ssp) return; - local_irq_save(flags); - if (ssp->port.sysrq) - locked = 0; - else if (oops_in_progress) - locked = uart_port_trylock(&ssp->port); + if (oops_in_progress) + locked = uart_port_trylock_irqsave(&ssp->port, &flags); else - uart_port_lock(&ssp->port); + uart_port_lock_irqsave(&ssp->port, &flags); ier = __ssp_readl(ssp, SIFIVE_SERIAL_IE_OFFS); __ssp_writel(0, SIFIVE_SERIAL_IE_OFFS, ssp); @@ -807,8 +805,7 @@ static void sifive_serial_console_write(struct console *co, const char *s, __ssp_writel(ier, SIFIVE_SERIAL_IE_OFFS, ssp); if (locked) - uart_port_unlock(&ssp->port); - local_irq_restore(flags); + uart_port_unlock_irqrestore(&ssp->port, flags); } static int sifive_serial_console_setup(struct console *co, char *options) -- 2.43.0 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2024-03-01 21:52 UTC|newest] Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-03-01 21:45 [PATCH 00/18] serial: Use uart_prepare_sysrq_char() Sebastian Andrzej Siewior 2024-03-01 21:45 ` [PATCH 01/18] serial: amba-pl011: " Sebastian Andrzej Siewior 2024-03-01 21:45 ` [PATCH 02/18] serial: ar933x: " Sebastian Andrzej Siewior 2024-03-01 21:45 ` [PATCH 03/18] serial: bcm63xx: " Sebastian Andrzej Siewior 2024-03-01 21:45 ` [PATCH 04/18] serial: meson: " Sebastian Andrzej Siewior 2024-03-01 21:45 ` Sebastian Andrzej Siewior 2024-03-01 21:45 ` Sebastian Andrzej Siewior 2024-03-01 21:45 ` [PATCH 05/18] serial: msm: " Sebastian Andrzej Siewior 2024-03-01 21:45 ` [PATCH 06/18] serial: omap: " Sebastian Andrzej Siewior 2024-03-01 21:45 ` [PATCH 07/18] serial: pxa: " Sebastian Andrzej Siewior 2024-03-01 21:45 ` [PATCH 08/18] serial: sunplus: " Sebastian Andrzej Siewior 2024-03-01 21:45 ` [PATCH 09/18] serial: lpc32xx_hs: Use uart_prepare_sysrq_char() to handle sysrq Sebastian Andrzej Siewior 2024-03-01 21:45 ` Sebastian Andrzej Siewior 2024-03-01 21:45 ` [PATCH 10/18] serial: owl: " Sebastian Andrzej Siewior 2024-03-01 21:45 ` Sebastian Andrzej Siewior 2024-03-01 21:45 ` [PATCH 11/18] serial: rda: " Sebastian Andrzej Siewior 2024-03-01 21:45 ` Sebastian Andrzej Siewior 2024-03-01 21:45 ` Sebastian Andrzej Siewior [this message] 2024-03-01 21:45 ` [PATCH 12/18] serial: sifive: " Sebastian Andrzej Siewior 2024-03-07 1:39 ` Samuel Holland 2024-03-07 1:39 ` Samuel Holland 2024-03-01 21:45 ` [PATCH 13/18] serial: pch: Invoke handle_rx_to() directly Sebastian Andrzej Siewior 2024-03-01 21:45 ` [PATCH 14/18] serial: pch: Make push_rx() return void Sebastian Andrzej Siewior 2024-03-01 21:45 ` [PATCH 15/18] serial: pch: Don't disable interrupts while acquiring lock in ISR Sebastian Andrzej Siewior 2024-03-01 21:45 ` [PATCH 16/18] serial: pch: Don't initialize uart_port's spin_lock Sebastian Andrzej Siewior 2024-03-01 21:45 ` [PATCH 17/18] serial: pch: Remove eg20t_port::lock Sebastian Andrzej Siewior 2024-03-01 21:45 ` [PATCH 18/18] serial: pch: Use uart_prepare_sysrq_char() Sebastian Andrzej Siewior
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