Commit d9d715f3 authored by Esben Haabendal's avatar Esben Haabendal Committed by felix
Browse files

serial: imx: Introduce timeout when waiting on transmitter empty 

mainline inclusion
from mainline-v6.10-rc1
commit e533e4c62e9993e62e947ae9bbec34e4c7ae81c2
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAD0R6
CVE: CVE-2024-40967

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e533e4c62e9993e62e947ae9bbec34e4c7ae81c2



--------------------------------

By waiting at most 1 second for USR2_TXDC to be set, we avoid a potential
deadlock.

In case of the timeout, there is not much we can do, so we simply ignore
the transmitter state and optimistically try to continue.

Signed-off-by: default avatarEsben Haabendal <esben@geanix.com>
Acked-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
Link: https://lore.kernel.org/r/919647898c337a46604edcabaf13d42d80c0915d.1712837613.git.esben@geanix.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Conflicts:
    drivers/tty/serial/imx.c
[Fix context conflicts]
Signed-off-by: default avatarFelix Fu <fuzhen5@huawei.com>
parent 0bf719c2

drivers/tty/serial/imx.c

+4 −3
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <linux/of.h>

#include <linux/of_device.h>

#include <linux/io.h>

#include <linux/iopoll.h>

#include <linux/dma-mapping.h>



#include <asm/irq.h>
@@ -2006,7 +2007,7 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count) 
{

	struct imx_port *sport = imx_uart_ports[co->index];

	struct imx_port_ucrs old_ucr;

	unsigned int ucr1;

	unsigned int ucr1, usr2;

	unsigned long flags = 0;

	int locked = 1;
@@ -2038,8 +2039,8 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count) 
	 *	Finally, wait for transmitter to become empty

	 *	and restore UCR1/2/3

	 */

	while (!(imx_uart_readl(sport, USR2) & USR2_TXDC));



	read_poll_timeout_atomic(imx_uart_readl, usr2, usr2 & USR2_TXDC,

				 0, USEC_PER_SEC, false, sport, USR2);

	imx_uart_ucrs_restore(sport, &old_ucr);



	if (locked)