Linux Serial subsystem development
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From: Andy Chiu <andy.chiu@sifive.com>
To: linux-serial@vger.kernel.org, linux-riscv@lists.infradead.org,
	palmer@dabbelt.com, gregkh@linuxfoundation.org
Cc: paul.walmsley@sifive.com, jirislaby@kernel.org,
	Andy Chiu <andy.chiu@sifive.com>
Subject: [PATCH] tty: serial: manage irq with spin_lock_irqsave in SiFive console
Date: Thu,  1 Feb 2024 06:59:32 +0000	[thread overview]
Message-ID: <20240201065932.19899-1-andy.chiu@sifive.com> (raw)

It is not safe to call spin_lock() with irq disabled on RT-linux.
Instead, transfer the code segment to spin_lock_irqsave to make it work
on both RT and non-RT linux.

Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
---
 drivers/tty/serial/sifive.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/serial/sifive.c b/drivers/tty/serial/sifive.c
index fa4c9336924f..3f0ddf8bfa7b 100644
--- a/drivers/tty/serial/sifive.c
+++ b/drivers/tty/serial/sifive.c
@@ -788,13 +788,12 @@ 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 = spin_trylock(&ssp->port.lock);
+		locked = spin_trylock_irqsave(&ssp->port.lock, flags);
 	else
-		spin_lock(&ssp->port.lock);
+		spin_lock_irqsave(&ssp->port.lock, flags);
 
 	ier = __ssp_readl(ssp, SIFIVE_SERIAL_IE_OFFS);
 	__ssp_writel(0, SIFIVE_SERIAL_IE_OFFS, ssp);
@@ -804,8 +803,7 @@ static void sifive_serial_console_write(struct console *co, const char *s,
 	__ssp_writel(ier, SIFIVE_SERIAL_IE_OFFS, ssp);
 
 	if (locked)
-		spin_unlock(&ssp->port.lock);
-	local_irq_restore(flags);
+		spin_unlock_irqrestore(&ssp->port.lock, flags);
 }
 
 static int __init sifive_serial_console_setup(struct console *co, char *options)
-- 
2.17.1


             reply	other threads:[~2024-02-01  6:59 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-01  6:59 Andy Chiu [this message]
2024-02-01  7:21 ` [PATCH] tty: serial: manage irq with spin_lock_irqsave in SiFive console Jiri Slaby
2024-02-26  6:22   ` Andy Chiu

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