Commit 2ab4f401 authored by Cristian Marussi's avatar Cristian Marussi Committed by Sudeep Holla
Browse files

firmware: arm_scmi: Fix device node validation for mailbox transport 



When mailboxes are used as a transport it is possible to setup the SCMI
transport layer, depending on the underlying channels configuration, to use
one or two mailboxes, associated, respectively, to one or two, distinct,
shared memory areas: any other combination should be treated as invalid.

Add more strict checking of SCMI mailbox transport device node descriptors.

Fixes: 5c8a47a5 ("firmware: arm_scmi: Make scmi core independent of the transport type")
Cc: <stable@vger.kernel.org> # 4.19
Signed-off-by: default avatarCristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20230307162324.891866-1-cristian.marussi@arm.com


Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
parent b2b76e97

drivers/firmware/arm_scmi/mailbox.c

+37 −0
Original line number Diff line number Diff line
@@ -52,6 +52,39 @@ static bool mailbox_chan_available(struct device_node *of_node, int idx) 
					   "#mbox-cells", idx, NULL);

}



static int mailbox_chan_validate(struct device *cdev)

{

	int num_mb, num_sh, ret = 0;

	struct device_node *np = cdev->of_node;



	num_mb = of_count_phandle_with_args(np, "mboxes", "#mbox-cells");

	num_sh = of_count_phandle_with_args(np, "shmem", NULL);

	/* Bail out if mboxes and shmem descriptors are inconsistent */

	if (num_mb <= 0 || num_sh > 2 || num_mb != num_sh) {

		dev_warn(cdev, "Invalid channel descriptor for '%s'\n",

			 of_node_full_name(np));

		return -EINVAL;

	}



	if (num_sh > 1) {

		struct device_node *np_tx, *np_rx;



		np_tx = of_parse_phandle(np, "shmem", 0);

		np_rx = of_parse_phandle(np, "shmem", 1);

		/* SCMI Tx and Rx shared mem areas have to be distinct */

		if (!np_tx || !np_rx || np_tx == np_rx) {

			dev_warn(cdev, "Invalid shmem descriptor for '%s'\n",

				 of_node_full_name(np));

			ret = -EINVAL;

		}



		of_node_put(np_tx);

		of_node_put(np_rx);

	}



	return ret;

}



static int mailbox_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,

			      bool tx)

{
@@ -64,6 +97,10 @@ static int mailbox_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, 
	resource_size_t size;

	struct resource res;



	ret = mailbox_chan_validate(cdev);

	if (ret)

		return ret;



	smbox = devm_kzalloc(dev, sizeof(*smbox), GFP_KERNEL);

	if (!smbox)

		return -ENOMEM;