This is a note to let you know that I've just added the patch titled
serial: sh-sci: Fix off-by-one error in FIFO threshold register
to my tty git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git in the tty-linus branch.
The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.
If you have any questions about this process, please let me know.
From 2ea2e019c190ee3973ef7bcaf829d8762e56e635 Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven geert+renesas@glider.be Date: Mon, 10 May 2021 14:07:55 +0200 Subject: serial: sh-sci: Fix off-by-one error in FIFO threshold register setting
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 --- 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 ef37fdf37612..4baf1316ea72 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1023,10 +1023,10 @@ 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) {