1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
|
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Fri, 1 Mar 2024 22:45:19 +0100
Subject: [PATCH 06/18] serial: omap: Use uart_prepare_sysrq_char().
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.8/older/patches-6.8.2-rt11.tar.xz
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.
Link: https://lore.kernel.org/r/20240301215246.891055-7-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
drivers/tty/serial/omap-serial.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -508,7 +508,7 @@ static void serial_omap_rdi(struct uart_
up->port.icount.rx++;
- if (uart_handle_sysrq_char(&up->port, ch))
+ if (uart_prepare_sysrq_char(&up->port, ch))
return;
uart_insert_char(&up->port, lsr, UART_LSR_OE, ch, TTY_NORMAL);
@@ -563,7 +563,7 @@ static irqreturn_t serial_omap_irq(int i
}
} while (max_count--);
- uart_port_unlock(&up->port);
+ uart_unlock_and_check_sysrq(&up->port);
tty_flip_buffer_push(&up->port.state->port);
@@ -1212,13 +1212,10 @@ serial_omap_console_write(struct console
unsigned int ier;
int locked = 1;
- local_irq_save(flags);
- if (up->port.sysrq)
- locked = 0;
- else if (oops_in_progress)
- locked = uart_port_trylock(&up->port);
+ if (oops_in_progress)
+ locked = uart_port_trylock_irqsave(&up->port, &flags);
else
- uart_port_lock(&up->port);
+ uart_port_lock_irqsave(&up->port, &flags);
/*
* First save the IER then disable the interrupts
@@ -1245,8 +1242,7 @@ serial_omap_console_write(struct console
check_modem_status(up);
if (locked)
- uart_port_unlock(&up->port);
- local_irq_restore(flags);
+ uart_port_unlock_irqrestore(&up->port, flags);
}
static int __init
|
