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

Douglas Anderson
2018-10-29T18:08:35Z

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@chromium.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@ozlabs.org>, IBM Corp.
* Copyright (C) 2006 Arnd Bergmann <arnd@arndb.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