Messages in this thread | | | Subject | Re: [PATCH] ACPI/IORT: Fix iort_node_get_id() mapping entries indexing | From | Sinan Kaya <> | Date | Sat, 7 Jan 2017 16:09:33 -0500 |
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On 1/5/2017 1:29 PM, 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@linaro.org> > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> > Cc: Hanjun Guo <hanjun.guo@linaro.org> > Cc: Sinan Kaya <okaya@codeaurora.org> > Cc: Tomasz Nowicki <tn@semihalf.com> > Cc: Nate Watterson <nwatters@codeaurora.org> > Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> > --- > 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));
What does this give us that the previous code didn't do?
You are using map as a pointer and returning the offset of the first map entry above and then accessing the map at the indexed offset with map[index]
The new code is using map as a plain pointer, calculating the pointer location with ACPI_ADD_PTR instead and then collecting the output parameter with map->output_base.
> > /* 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;
You are claiming that the existing code is collecting the output parameter from the first mapping. I don't see this happening above.
What am I missing?
> return parent; > } > } >
If we are just doing a housekeeping, this is fine. I couldn't see an actual bug getting fixed.
-- Sinan Kaya Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
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