net/fsl_pq_mdio: check TBI address for consistency with mapped range
authorGerlando Falauto <gerlando.falauto@keymile.com>
Mon, 12 Oct 2015 07:18:40 +0000 (09:18 +0200)
committerDavid S. Miller <davem@davemloft.net>
Tue, 13 Oct 2015 11:29:54 +0000 (04:29 -0700)
When configuring the MDIO subsystem it is also necessary to configure
the TBI register. Make sure the TBI is contained within the mapped
register range in order to:
a) make sure the address is computed correctly
b) make users aware that we're actually accessing that register

In case of error, print a message but continue anyway.

Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
Cc: Timur Tabi <timur@tabi.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/ethernet/freescale/fsl_pq_mdio.c

index 3c40f6b9922436a32d255aa627e9d94db45f8477..5333d0afceba8ef46b21c7d2cb4a7b5c5bb5e2d6 100644 (file)
@@ -445,6 +445,16 @@ static int fsl_pq_mdio_probe(struct platform_device *pdev)
 
                        tbipa = data->get_tbipa(priv->map);
 
+                       /*
+                        * Add consistency check to make sure TBI is contained
+                        * within the mapped range (not because we would get a
+                        * segfault, rather to catch bugs in computing TBI
+                        * address). Print error message but continue anyway.
+                        */
+                       if ((void *)tbipa > priv->map + resource_size(&res) - 4)
+                               dev_err(&pdev->dev, "invalid register map (should be at least 0x%04x to contain TBI address)\n",
+                                       ((void *)tbipa - priv->map) + 4);
+
                        iowrite32be(be32_to_cpup(prop), tbipa);
                }
        }