Subject: [PATCH AUTOSEL 5.4 154/459] net/wan/fsl_ucc_hdlc: reject muram offsets above 64K

From: Sasha Levin <[email-masked]>
Date: Fri, 14 Feb 2020 10:56:44 -0500

From: Rasmus Villemoes <[email-masked]>

[ 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 <[email-masked]>
Reviewed-by: Timur Tabi <[email-masked]>
Signed-off-by: Rasmus Villemoes <[email-masked]>
Acked-by: David S. Miller <[email-masked]>
Signed-off-by: Li Yang <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 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 aef7de225783f..4ad0a0c33d853 100644
--- a/drivers/net/wan/fsl_ucc_hdlc.c
+++ b/drivers/net/wan/fsl_ucc_hdlc.c
@@ -245,6 +245,11 @@ 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