From: Geert Uytterhoeven geert+renesas@glider.be
commit 2ea2e019c190ee3973ef7bcaf829d8762e56e635 upstream.
The Receive FIFO Data Count Trigger field (RTRG[6:0]) in the Receive FIFO Data Count Trigger Register (HSRTRGR) of HSCIF can only hold values ranging from 0-127. As the FIFO size is equal to 128 on HSCIF, the user can write an out-of-range value, touching reserved bits.
Fix this by limiting the trigger value to the FIFO size minus one. Reverse the order of the checks, to avoid rx_trig becoming zero if the FIFO size is one.
Note that this change has no impact on other SCIF variants, as their maximum supported trigger value is lower than the FIFO size anyway, and the code below takes care of enforcing these limits.
Fixes: a380ed461f66d1b8 ("serial: sh-sci: implement FIFO threshold register setting") Reported-by: Linh Phung linh.phung.jy@renesas.com Reviewed-by: Wolfram Sang wsa+renesas@sang-engineering.com Reviewed-by: Ulrich Hecht uli+renesas@fpond.eu Signed-off-by: Geert Uytterhoeven geert+renesas@glider.be Cc: stable stable@vger.kernel.org Link: https://lore.kernel.org/r/5eff320aef92ffb33d00e57979fd3603bbb4a70f.162064821... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- 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 8aaa7900927a8..bfbfe0d68d828 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1026,10 +1026,10 @@ static int scif_set_rtrg(struct uart_port *port, int rx_trig) { unsigned int bits;
+ if (rx_trig >= port->fifosize) + rx_trig = port->fifosize - 1; if (rx_trig < 1) rx_trig = 1; - if (rx_trig >= port->fifosize) - rx_trig = port->fifosize;
/* HSCIF can be set to an arbitrary level. */ if (sci_getreg(port, HSRTRGR)->size) {