[PATCH AUTOSEL 4.9 049/141] net/wan/fsl_ucc_hdlc: reject muram offsets above 64K

[Sasha Levin]

From: Rasmus Villemoes <linux at rasmusvillemoes.dk>

[ Upstream commit 148587a59f6b85831695e0497d9dd1af5f0495af ]

Qiang Zhao points out that these offsets get written to 16-bit
registers, and there are some QE platforms with more than 64K
muram. So it is possible that qe_muram_alloc() gives us an allocation
that can't actually be used by the hardware, so detect and reject
that.

Reported-by: Qiang Zhao <qiang.zhao at nxp.com>
Reviewed-by: Timur Tabi <timur at kernel.org>
Signed-off-by: Rasmus Villemoes <linux at rasmusvillemoes.dk>
Acked-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Li Yang <leoyang.li at nxp.com>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 drivers/net/wan/fsl_ucc_hdlc.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/wan/fsl_ucc_hdlc.c b/drivers/net/wan/fsl_ucc_hdlc.c
index af85a1b3135e2..87bf05a81db50 100644
--- a/drivers/net/wan/fsl_ucc_hdlc.c
+++ b/drivers/net/wan/fsl_ucc_hdlc.c
@@ -209,6 +209,11 @@ static int uhdlc_init(struct ucc_hdlc_private *priv)
 		ret = -ENOMEM;
 		goto free_riptr;
 	}
+	if (riptr != (u16)riptr || tiptr != (u16)tiptr) {
+		dev_err(priv->dev, "MURAM allocation out of addressable range\n");
+		ret = -ENOMEM;
+		goto free_tiptr;
+	}
 
 	/* Set RIPTR, TIPTR */
 	iowrite16be(riptr, &priv->ucc_pram->riptr);
-- 
2.20.1