mcb-pci: Reallocate memory region to avoid memory overlapping

mcb-pci requests a fixed-size memory region to parse the chameleon
table, however, if the chameleon table is smaller that the allocated
region, it could overlap with the IP Cores' memory regions.

After parsing the chameleon table, drop/reallocate the memory region
with the actual chameleon table size.

Co-developed-by: Jorge Sanjuan Garcia <jorge.sanjuangarcia@duagon.com>
Signed-off-by: Jorge Sanjuan Garcia <jorge.sanjuangarcia@duagon.com>
Signed-off-by: Javier Rodriguez <josejavier.rodriguez@duagon.com>
Signed-off-by: Johannes Thumshirn <jth@kernel.org>
Link: https://lore.kernel.org/r/20230411083329.4506-3-jth@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/mcb/mcb-pci.c b/drivers/mcb/mcb-pci.c
index dc88232d9af83c1694d6e00d122d45cecc1eb45b..53d9202ff9a7ce1b4a24e9aba50e2fb90ddb759a 100644 (file)
--- a/drivers/mcb/mcb-pci.c
+++ b/drivers/mcb/mcb-pci.c
@@ -31,7 +31,7 @@ static int mcb_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
        struct resource *res;
        struct priv *priv;
-       int ret;
+       int ret, table_size;
        unsigned long flags;
 
        priv = devm_kzalloc(&pdev->dev, sizeof(struct priv), GFP_KERNEL);
@@ -90,7 +90,30 @@ static int mcb_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
        if (ret < 0)
                goto out_mcb_bus;
 
-       dev_dbg(&pdev->dev, "Found %d cells\n", ret);
+       table_size = ret;
+
+       if (table_size < CHAM_HEADER_SIZE) {
+               /* Release the previous resources */
+               devm_iounmap(&pdev->dev, priv->base);
+               devm_release_mem_region(&pdev->dev, priv->mapbase, CHAM_HEADER_SIZE);
+
+               /* Then, allocate it again with the actual chameleon table size */
+               res = devm_request_mem_region(&pdev->dev, priv->mapbase,
+                                               table_size,
+                                               KBUILD_MODNAME);
+               if (!res) {
+                       dev_err(&pdev->dev, "Failed to request PCI memory\n");
+                       ret = -EBUSY;
+                       goto out_mcb_bus;
+               }
+
+               priv->base = devm_ioremap(&pdev->dev, priv->mapbase, table_size);
+               if (!priv->base) {
+                       dev_err(&pdev->dev, "Cannot ioremap\n");
+                       ret = -ENOMEM;
+                       goto out_mcb_bus;
+               }
+       }
 
        mcb_bus_add_devices(priv->bus);