Re: [PATCH] ACPI/IORT: Fix iort_node_get_id() mapping entries indexing

From: Hanjun Guo
Date: Mon Jan 09 2017 - 03:01:25 EST


On 2017/1/6 2:29, Lorenzo Pieralisi wrote:
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 <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>
---
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;
}
}

Reviewed-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>