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Commit618f535a60("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:618f535a60("ACPI/IORT: Add single mapping function") Reported-by: Hanjun Guo <hanjun.guo@linaro.org> Reviewed-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> Signed-off-by: Will Deacon <will.deacon@arm.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.