linux-kernel - [PATCH AUTOSEL 4.19 01/73] serial: sh-sci: Fix receive on SCIFA/SCIFB variants with DMA

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 14 Nov 2018 17:20:55 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     stable@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Geert Uytterhoeven <geert+renesas@...der.be>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 4.19 01/73] serial: sh-sci: Fix receive on SCIFA/SCIFB variants with DMA

From: Geert Uytterhoeven <geert+renesas@...der.be>

[ Upstream commit 202dc3cc10b4d37e5251431acf8d5040a8876c7d ]

On SCIFA and SCIFB serial ports with DMA support (i.e. some ports on
R-Car Gen2 and RZ/G1 SoCs), receive DMA operations are submitted before
the DMA channel pointer is initialized.  Hence this fails, and the
driver tries to fall back to PIO.  However, at this early phase in the
initialization sequence, fallback to PIO does not work, leading to a
serial port that cannot receive any data.

Fix this by calling sci_submit_rx() after initialization of the DMA
channel pointer.

Reported-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
Fixes: 2c4ee23530ffc022 ("serial: sh-sci: Postpone DMA release when falling back to PIO")
Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
Reviewed-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/tty/serial/sh-sci.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index ab3f6e91853d..e19bfbba8a01 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1614,10 +1614,10 @@ static void sci_request_dma(struct uart_port *port)
 		hrtimer_init(&s->rx_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 		s->rx_timer.function = rx_timer_fn;
 
+		s->chan_rx_saved = s->chan_rx = chan;
+
 		if (port->type == PORT_SCIFA || port->type == PORT_SCIFB)
 			sci_submit_rx(s);
-
-		s->chan_rx_saved = s->chan_rx = chan;
 	}
 }
 
-- 
2.17.1