Hi Mathieu,
On 04/10/2020 07:17 PM, Mathieu Poirier wrote:
Hi Suzuki,
On Thu, Apr 09, 2020 at 12:03:16PM +0100, Suzuki K Poulose wrote:
On some systems the firmware may not describe all the ports
connected to a component (e.g, for security reasons). This
could be especially problematic for "funnels" where we could
end up in modifying memory beyond the allocated space for
refcounts.
...
@@ -672,10 +687,14 @@ static int acpi_coresight_parse_graph(struct acpi_device *adev,
return dir;
if (dir == ACPI_CORESIGHT_LINK_MASTER) {
- pdata->nr_outport++;
+ if (ptr->outport > pdata->nr_outport)
+ pdata->nr_outport = ptr->outport;
ptr++;
} else {
- pdata->nr_inport++;
+ WARN_ON(pdata->nr_inport == ptr->child_port);
+ /* Do not move the ptr for input connections */
+ if (ptr->child_port > pdata->nr_inport)
+ pdata->nr_inport = ptr->child_port;
How you are using the current ptr as a scratch pad for input port was definitely
a brain twister this morning... I would certainly appreciate a richer comment
so that I (or anyone else) doesn't have to go through the same process the next
time around.
Sure, it deserves a better comment. I will add something like :
/*
* We don't track input connection details for a device,
* except for the highest input port number. Thus we could
* reuse the current record as a scratch pad and reuse it
* by not moving the ptr ahead.
*/
/**
- * struct coresight_platform_data - data harvested from the DT specification
- * @nr_inport: number of input ports for this component.
- * @nr_outport: number of output ports for this component.
- * @conns: Array of nr_outport connections from this component
+ * struct coresight_platform_data - data harvested from the firmware
+ * specification.
+ *
+ * @nr_inport: Number of elements for the input connections.
+ * @nr_outport: Number of elements for the output connections.
+ * @conns: Sparse arrray of nr_outport connections from this component.
s/arrray/array
Please rebase your work on my the coresight-next branch. Other than the above
this patch looks fine to me.
Thanks for the heads up, will do.
Cheers
Suzuki
