Commit 618f535a6062 ("ACPI/IORT: Add single mapping function")
introduced a function (iort_node_get_id()) to retrieve ids for IORT
named components.

iort_node_get_id() takes an index as input to refer to a specific
mapping entry in the mapping array to retrieve the id at a specific
index provided the index is below the total mapping count; currently the
index is used to retrieve the mapping value from the correct entry but
not to dereference the correct entry while retrieving the mapping
output_reference (ie IORT parent pointer), which consequently always
resolves to the output_reference of the first entry in the mapping
array.

Update the map array entry pointer computation in iort_node_get_id() to
take into account the index value, fixing the issue.

Fixes: 618f535a6062 ("ACPI/IORT: Add single mapping function")
Reported-by: Hanjun Guo <[email protected]>
Signed-off-by: Lorenzo Pieralisi <[email protected]>
Cc: Hanjun Guo <[email protected]>
Cc: Sinan Kaya <[email protected]>
Cc: Tomasz Nowicki <[email protected]>
Cc: Nate Watterson <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
---
 drivers/acpi/arm64/iort.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index e0d2e6e..ba156c5 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -333,7 +333,7 @@ struct acpi_iort_node *iort_node_get_id(struct 
acpi_iort_node *node,
                return NULL;
 
        map = ACPI_ADD_PTR(struct acpi_iort_id_mapping, node,
-                          node->mapping_offset);
+                          node->mapping_offset + index * sizeof(*map));
 
        /* Firmware bug! */
        if (!map->output_reference) {
@@ -348,10 +348,10 @@ struct acpi_iort_node *iort_node_get_id(struct 
acpi_iort_node *node,
        if (!(IORT_TYPE_MASK(parent->type) & type_mask))
                return NULL;
 
-       if (map[index].flags & ACPI_IORT_ID_SINGLE_MAPPING) {
+       if (map->flags & ACPI_IORT_ID_SINGLE_MAPPING) {
                if (node->type == ACPI_IORT_NODE_NAMED_COMPONENT ||
                    node->type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX) {
-                       *id_out = map[index].output_base;
+                       *id_out = map->output_base;
                        return parent;
                }
        }
-- 
2.10.0

Reply via email to