linux-kernel - [PATCH 5/7] serial: 8250: Process sysrq at port unlock time

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Message-Id: <20181029180707.207546-6-dianders@chromium.org>
Date:   Mon, 29 Oct 2018 11:07:05 -0700
From:   Douglas Anderson <dianders@...omium.org>
To:     Jason Wessel <jason.wessel@...driver.com>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        tglx@...utronix.de, mingo@...nel.org, gregkh@...uxfoundation.org
Cc:     linux-arm-msm@...r.kernel.org,
        kgdb-bugreport@...ts.sourceforge.net,
        Douglas Anderson <dianders@...omium.org>, nm@...com,
        marex@...x.de, vigneshr@...com, linux-aspeed@...ts.ozlabs.org,
        jk@...abs.org, andrew@...id.au, rolf.evers.fischer@...iv.com,
        linux-kernel@...r.kernel.org, tony@...mide.com,
        Jisheng.Zhang@...aptics.com, joel@....id.au,
        linux-serial@...r.kernel.org, jslaby@...e.com, asierra@...-inc.com,
        andriy.shevchenko@...ux.intel.com, dan.carpenter@...cle.com,
        linux-arm-kernel@...ts.infradead.org
Subject: [PATCH 5/7] serial: 8250: Process sysrq at port unlock time

Let's take advantage of the new ("serial: core: Allow processing sysrq
at port unlock time") to handle sysrqs more cleanly.

Signed-off-by: Douglas Anderson <dianders@...omium.org>
---
I don't have a great way to test all 8250 variants, but I've at least
tested rk3288 / rk3399 and they seem to work.  Hopefully I got the
aspeed_vuart / fsl / omap variants right (I only compile tested
those).

 drivers/tty/serial/8250/8250_aspeed_vuart.c | 6 +++++-
 drivers/tty/serial/8250/8250_fsl.c          | 6 +++++-
 drivers/tty/serial/8250/8250_omap.c         | 6 +++++-
 drivers/tty/serial/8250/8250_port.c         | 8 +++-----
 4 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_aspeed_vuart.c b/drivers/tty/serial/8250/8250_aspeed_vuart.c
index 435bec40dee6..0438d9a905ce 100644
--- a/drivers/tty/serial/8250/8250_aspeed_vuart.c
+++ b/drivers/tty/serial/8250/8250_aspeed_vuart.c
@@ -5,6 +5,10 @@
  *    Copyright (C) 2016 Jeremy Kerr <jk@...abs.org>, IBM Corp.
  *    Copyright (C) 2006 Arnd Bergmann <arnd@...db.de>, IBM Corp.
  */
+#if defined(CONFIG_SERIAL_8250_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
@@ -293,7 +297,7 @@ static int aspeed_vuart_handle_irq(struct uart_port *port)
 	if (lsr & UART_LSR_THRE)
 		serial8250_tx_chars(up);
 
-	spin_unlock_irqrestore(&port->lock, flags);
+	uart_unlock_and_check_sysrq(port, flags);
 
 	return 1;
 }
diff --git a/drivers/tty/serial/8250/8250_fsl.c b/drivers/tty/serial/8250/8250_fsl.c
index 6640a4c7ddd1..ff3dcaea5d93 100644
--- a/drivers/tty/serial/8250/8250_fsl.c
+++ b/drivers/tty/serial/8250/8250_fsl.c
@@ -1,4 +1,8 @@
 // SPDX-License-Identifier: GPL-2.0
+#if defined(CONFIG_SERIAL_8250_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
 #include <linux/serial_reg.h>
 #include <linux/serial_8250.h>
 
@@ -54,7 +58,7 @@ int fsl8250_handle_irq(struct uart_port *port)
 		serial8250_tx_chars(up);
 
 	up->lsr_saved_flags = orig_lsr;
-	spin_unlock_irqrestore(&up->port.lock, flags);
+	uart_unlock_and_check_sysrq(&up->port, flags);
 	return 1;
 }
 EXPORT_SYMBOL_GPL(fsl8250_handle_irq);
diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index a019286f8bb6..ad7ba7d0f28d 100644
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -8,6 +8,10 @@
  *
  */
 
+#if defined(CONFIG_SERIAL_8250_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
 #include <linux/device.h>
 #include <linux/io.h>
 #include <linux/module.h>
@@ -1085,7 +1089,7 @@ static int omap_8250_dma_handle_irq(struct uart_port *port)
 		}
 	}
 
-	spin_unlock_irqrestore(&port->lock, flags);
+	uart_unlock_and_check_sysrq(port, flags);
 	serial8250_rpm_put(up);
 	return 1;
 }
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index f776b3eafb96..c39482b96111 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1755,7 +1755,7 @@ void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr)
 		else if (lsr & UART_LSR_FE)
 			flag = TTY_FRAME;
 	}
-	if (uart_handle_sysrq_char(port, ch))
+	if (uart_prepare_sysrq_char(port, ch))
 		return;
 
 	uart_insert_char(port, lsr, UART_LSR_OE, ch, flag);
@@ -1897,7 +1897,7 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
 	if ((!up->dma || up->dma->tx_err) && (status & UART_LSR_THRE))
 		serial8250_tx_chars(up);
 
-	spin_unlock_irqrestore(&port->lock, flags);
+	uart_unlock_and_check_sysrq(port, flags);
 	return 1;
 }
 EXPORT_SYMBOL_GPL(serial8250_handle_irq);
@@ -3258,9 +3258,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
 
 	serial8250_rpm_get(up);
 
-	if (port->sysrq)
-		locked = 0;
-	else if (oops_in_progress)
+	if (oops_in_progress)
 		locked = spin_trylock_irqsave(&port->lock, flags);
 	else
 		spin_lock_irqsave(&port->lock, flags);
-- 
2.19.1.568.g152ad8e336-goog