[08/18] serial: sunplus: Use uart_prepare_sysrq_char().

Message ID	20240301215246.891055-9-bigeasy@linutronix.de
State	New
Headers	show Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 410AB58AD7 for <linux-serial@vger.kernel.org>; Fri, 1 Mar 2024 21:52:55 +0000 (UTC) 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>, Hammer Hsieh <hammerh0314@gmail.com> Subject: [PATCH 08/18] serial: sunplus: Use uart_prepare_sysrq_char(). Date: Fri, 1 Mar 2024 22:45:21 +0100 Message-ID: <20240301215246.891055-9-bigeasy@linutronix.de> In-Reply-To: <20240301215246.891055-1-bigeasy@linutronix.de> References: <20240301215246.891055-1-bigeasy@linutronix.de> Precedence: bulk MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable
Series	serial: Use uart_prepare_sysrq_char(). \| expand [00/18] serial: Use uart_prepare_sysrq_char(). [01/18] serial: amba-pl011: Use uart_prepare_sysrq_char(). [02/18] serial: ar933x: Use uart_prepare_sysrq_char(). [03/18] serial: bcm63xx: Use uart_prepare_sysrq_char(). [04/18] serial: meson: Use uart_prepare_sysrq_char(). [05/18] serial: msm: Use uart_prepare_sysrq_char(). [06/18] serial: omap: Use uart_prepare_sysrq_char(). [07/18] serial: pxa: Use uart_prepare_sysrq_char(). [08/18] serial: sunplus: Use uart_prepare_sysrq_char(). [09/18] serial: lpc32xx_hs: Use uart_prepare_sysrq_char() to handle sysrq. [10/18] serial: owl: Use uart_prepare_sysrq_char() to handle sysrq. [11/18] serial: rda: Use uart_prepare_sysrq_char() to handle sysrq. [12/18] serial: sifive: Use uart_prepare_sysrq_char() to handle sysrq. [13/18] serial: pch: Invoke handle_rx_to() directly. [14/18] serial: pch: Make push_rx() return void. [15/18] serial: pch: Don't disable interrupts while acquiring lock in ISR. [16/18] serial: pch: Don't initialize uart_port's spin_lock. [17/18] serial: pch: Remove eg20t_port::lock. [18/18] serial: pch: Use uart_prepare_sysrq_char().

Message ID

20240301215246.891055-9-bigeasy@linutronix.de

State

New

Headers

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>,
	Hammer Hsieh <hammerh0314@gmail.com>
Subject: [PATCH 08/18] serial: sunplus: Use uart_prepare_sysrq_char().
Date: Fri,  1 Mar 2024 22:45:21 +0100
Message-ID: <20240301215246.891055-9-bigeasy@linutronix.de>
In-Reply-To: <20240301215246.891055-1-bigeasy@linutronix.de>
References: <20240301215246.891055-1-bigeasy@linutronix.de>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable

Series

serial: Use uart_prepare_sysrq_char(). | expand

Commit Message

Sebastian Andrzej Siewior March 1, 2024, 9:45 p.m. UTC

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.

Delay handling sysrq until port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.

Cc: Hammer Hsieh <hammerh0314@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/tty/serial/sunplus-uart.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/drivers/tty/serial/sunplus-uart.c b/drivers/tty/serial/sunplus-uart.c
index 99f5285819d4b..f5e29eb4a4ce4 100644
--- a/drivers/tty/serial/sunplus-uart.c
+++ b/drivers/tty/serial/sunplus-uart.c
@@ -260,7 +260,7 @@  static void receive_chars(struct uart_port *port)
 		if (port->ignore_status_mask & SUP_DUMMY_READ)
 			goto ignore_char;
 
-		if (uart_handle_sysrq_char(port, ch))
+		if (uart_prepare_sysrq_char(port, ch))
 			goto ignore_char;
 
 		uart_insert_char(port, lsr, SUP_UART_LSR_OE, ch, flag);
@@ -287,7 +287,7 @@  static irqreturn_t sunplus_uart_irq(int irq, void *args)
 	if (isc & SUP_UART_ISC_TX)
 		transmit_chars(port);
 
-	uart_port_unlock(port);
+	uart_unlock_and_check_sysrq(port);
 
 	return IRQ_HANDLED;
 }
@@ -512,22 +512,16 @@  static void sunplus_console_write(struct console *co,
 	unsigned long flags;
 	int locked = 1;
 
-	local_irq_save(flags);
-
-	if (sunplus_console_ports[co->index]->port.sysrq)
-		locked = 0;
-	else if (oops_in_progress)
-		locked = uart_port_trylock(&sunplus_console_ports[co->index]->port);
+	if (oops_in_progress)
+		locked = uart_port_trylock_irqsave(&sunplus_console_ports[co->index]->port, &flags);
 	else
-		uart_port_lock(&sunplus_console_ports[co->index]->port);
+		uart_port_lock_irqsave(&sunplus_console_ports[co->index]->port, &flags);
 
 	uart_console_write(&sunplus_console_ports[co->index]->port, s, count,
 			   sunplus_uart_console_putchar);
 
 	if (locked)
-		uart_port_unlock(&sunplus_console_ports[co->index]->port);
-
-	local_irq_restore(flags);
+		uart_port_unlock_irqrestore(&sunplus_console_ports[co->index]->port, flags);
 }
 
 static int __init sunplus_console_setup(struct console *co, char *options)

[08/18] serial: sunplus: Use uart_prepare_sysrq_char().

Commit Message

Patch