Patch "mcb-pci: Reallocate memory region to avoid memory overlapping" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    mcb-pci: Reallocate memory region to avoid memory overlapping

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mcb-pci-reallocate-memory-region-to-avoid-memory-ove.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 0acf4e4a3a366afd0fef8c2122827944e5623c0b
Author: Rodríguez Barbarin, José Javier <JoseJavier.Rodriguez@xxxxxxxxxx>
Date:   Tue Apr 11 10:33:28 2023 +0200

    mcb-pci: Reallocate memory region to avoid memory overlapping
    
    [ Upstream commit 9be24faadd085c284890c3afcec7a0184642315a ]
    
    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@xxxxxxxxxx>
    Signed-off-by: Jorge Sanjuan Garcia <jorge.sanjuangarcia@xxxxxxxxxx>
    Signed-off-by: Javier Rodriguez <josejavier.rodriguez@xxxxxxxxxx>
    Signed-off-by: Johannes Thumshirn <jth@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20230411083329.4506-3-jth@xxxxxxxxxx
    Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/mcb/mcb-pci.c b/drivers/mcb/mcb-pci.c
index dc88232d9af83..53d9202ff9a7c 100644
--- 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);