Commit 618f535a6062 ("ACPI/IORT: Add single mapping function") introduced a function (iort_node_get_id()) to retrieve ids for IORT named components. The iort_node_get_id() takes an index as input to refer to a specific mapping entry in the named component IORT node mapping array. For a mapping entry at a given index, iort_node_get_id() should return the id value (through the id_out function parameter) and the IORT node output_reference (through function return value) the given mapping entry refers to. Technically output_reference values may differ for different map entries, (see diagram below - mapped id values may refer to different eg IORT SMMU nodes; the kernel may not be able to handle different output_reference values for a given named component but the IORT kernel layer should still report the IORT mappings as reported by firmware) but current code in iort_node_get_id() fails to use the index function parameter to return the correct output_reference value (ie it always returns the output_reference value of the first entry in the mapping array whilst using the index correctly to retrieve the id value from the respective entry). |----------------------| | named component | |----------------------| | map entry[0] | |----------------------| | id value | | output_reference----------------> eg SMMU 1 |----------------------| | map entry[1] | |----------------------| | id value | | output_reference----------------> eg SMMU 2 |----------------------| . . . |----------------------| | map entry[N] | |----------------------| | id value | | output_reference----------------> eg SMMU 1 |----------------------| Consequently the iort_node_get_id() function always returns the IORT node pointed at by the output_reference value of the first named component mapping array entry, irrespective of the index parameter, which is a bug. 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 <hanjun.guo@xxxxxxxxxx> Reviewed-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> Cc: Hanjun Guo <hanjun.guo@xxxxxxxxxx> Cc: Sinan Kaya <okaya@xxxxxxxxxxxxxx> Cc: Tomasz Nowicki <tn@xxxxxxxxxxxx> Cc: Nate Watterson <nwatters@xxxxxxxxxxxxxx> Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx> --- v1 -> v2: - Updated/improved commit log - Added review tags 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 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html