Patch "mcb-lpc: Reallocate memory region to avoid memory overlapping" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    mcb-lpc: Reallocate memory region to avoid memory overlapping

to the 5.4-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-lpc-reallocate-memory-region-to-avoid-memory-ove.patch
and it can be found in the queue-5.4 subdirectory.

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



commit 7ccdac7722b5a71585d8780905ae5860772bf0ac
Author: Rodríguez Barbarin, José Javier <JoseJavier.Rodriguez@xxxxxxxxxx>
Date:   Tue Apr 11 10:33:29 2023 +0200

    mcb-lpc: Reallocate memory region to avoid memory overlapping
    
    [ Upstream commit 2025b2ca8004c04861903d076c67a73a0ec6dfca ]
    
    mcb-lpc 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/20230411083329.4506-4-jth@xxxxxxxxxx
    Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/mcb/mcb-lpc.c b/drivers/mcb/mcb-lpc.c
index 8f1bde437a7e1..92915d2c2d464 100644
--- a/drivers/mcb/mcb-lpc.c
+++ b/drivers/mcb/mcb-lpc.c
@@ -23,7 +23,7 @@ static int mcb_lpc_probe(struct platform_device *pdev)
 {
 	struct resource *res;
 	struct priv *priv;
-	int ret = 0;
+	int ret = 0, table_size;
 
 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
@@ -58,16 +58,43 @@ static int mcb_lpc_probe(struct platform_device *pdev)
 
 	ret = chameleon_parse_cells(priv->bus, priv->mem->start, priv->base);
 	if (ret < 0) {
-		mcb_release_bus(priv->bus);
-		return ret;
+		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->mem->start, resource_size(priv->mem));
+
+		/* Then, allocate it again with the actual chameleon table size */
+		res = devm_request_mem_region(&pdev->dev, priv->mem->start,
+					      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->mem->start, table_size);
+		if (!priv->base) {
+			dev_err(&pdev->dev, "Cannot ioremap\n");
+			ret = -ENOMEM;
+			goto out_mcb_bus;
+		}
+
+		platform_set_drvdata(pdev, priv);
+	}
 
 	mcb_bus_add_devices(priv->bus);
 
 	return 0;
 
+out_mcb_bus:
+	mcb_release_bus(priv->bus);
+	return ret;
 }
 
 static int mcb_lpc_remove(struct platform_device *pdev)