fsl/fman: Check for null pointer after calling devm_ioremap

As the possible failure of the allocation, the devm_ioremap() may return
NULL pointer.
Take tgec_initialization() as an example.
If allocation fails, the params->base_addr will be NULL pointer and will
be assigned to tgec->regs in tgec_config().
Then it will cause the dereference of NULL pointer in set_mac_address(),
which is called by tgec_init().
Therefore, it should be better to add the sanity check after the calling
of the devm_ioremap().

Fixes: 3933961 ("fsl/fman: Add FMan MAC driver")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/fman/mac.c

@@ -94,14 +94,17 @@ static void mac_exception(void *handle, enum fman_mac_exceptions ex)
 		__func__, ex);
 }
 
-static void set_fman_mac_params(struct mac_device *mac_dev,
-				struct fman_mac_params *params)
+static int set_fman_mac_params(struct mac_device *mac_dev,
+			       struct fman_mac_params *params)
 {
 	struct mac_priv_s *priv = mac_dev->priv;
 
 	params->base_addr = (typeof(params->base_addr))
 		devm_ioremap(priv->dev, mac_dev->res->start,
 			     resource_size(mac_dev->res));
+	if (!params->base_addr)
+		return -ENOMEM;
+
 	memcpy(&params->addr, mac_dev->addr, sizeof(mac_dev->addr));
 	params->max_speed	= priv->max_speed;
 	params->phy_if		= mac_dev->phy_if;
@@ -112,6 +115,8 @@ static void set_fman_mac_params(struct mac_device *mac_dev,
 	params->event_cb	= mac_exception;
 	params->dev_id		= mac_dev;
 	params->internal_phy_node = priv->internal_phy_node;
+
+	return 0;
 }
 
 static int tgec_initialization(struct mac_device *mac_dev)
@@ -123,7 +128,9 @@ static int tgec_initialization(struct mac_device *mac_dev)
 
 	priv = mac_dev->priv;
 
-	set_fman_mac_params(mac_dev, &params);
+	err = set_fman_mac_params(mac_dev, &params);
+	if (err)
+		goto _return;
 
 	mac_dev->fman_mac = tgec_config(&params);
 	if (!mac_dev->fman_mac) {
@@ -169,7 +176,9 @@ static int dtsec_initialization(struct mac_device *mac_dev)
 
 	priv = mac_dev->priv;
 
-	set_fman_mac_params(mac_dev, &params);
+	err = set_fman_mac_params(mac_dev, &params);
+	if (err)
+		goto _return;
 
 	mac_dev->fman_mac = dtsec_config(&params);
 	if (!mac_dev->fman_mac) {
@@ -218,7 +227,9 @@ static int memac_initialization(struct mac_device *mac_dev)
 
 	priv = mac_dev->priv;
 
-	set_fman_mac_params(mac_dev, &params);
+	err = set_fman_mac_params(mac_dev, &params);
+	if (err)
+		goto _return;
 
 	if (priv->max_speed == SPEED_10000)
 		params.phy_if = PHY_INTERFACE_MODE_XGMII;