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Re: [PATCH v2] ACPI/IORT: Fix iort_node_get_id() mapping entries indexing

Started byHanjun Guo <hanjun.guo@linaro.org>
First post2017-02-03 03:30 +0100
Last post2017-02-03 10:00 +0100
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  Re: [PATCH v2] ACPI/IORT: Fix iort_node_get_id() mapping entries  indexing Hanjun Guo <hanjun.guo@linaro.org> - 2017-02-03 03:30 +0100
    Re: [PATCH v2] ACPI/IORT: Fix iort_node_get_id() mapping entries  indexing Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> - 2017-02-03 10:00 +0100

#1572856 — Re: [PATCH v2] ACPI/IORT: Fix iort_node_get_id() mapping entries indexing

FromHanjun Guo <hanjun.guo@linaro.org>
Date2017-02-03 03:30 +0100
SubjectRe: [PATCH v2] ACPI/IORT: Fix iort_node_get_id() mapping entries indexing
Message-ID<t6BNo-3QZ-5@gated-at.bofh.it>
On 01/10/2017 08:00 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.
>
> 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@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>
> ---
> v1 -> v2:
> 	- Updated/improved commit log
> 	- Added review tags

Forgot to mention that I tested this patch on Hisilicon
D03,

Tested-by: Hanjun Guo <hanjun.guo@linaro.org>

BTW, Lorenzo, Rafael, since it's a bugfix, can this be merged into
4.10-rc7?

Thanks
Hanjun

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#1572951

FromLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Date2017-02-03 10:00 +0100
Message-ID<t6HSO-7MR-5@gated-at.bofh.it>
In reply to#1572856
On Fri, Feb 03, 2017 at 10:20:29AM +0800, Hanjun Guo wrote:
> On 01/10/2017 08:00 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.
> >
> >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@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>
> >---
> >v1 -> v2:
> >	- Updated/improved commit log
> >	- Added review tags
> 
> Forgot to mention that I tested this patch on Hisilicon
> D03,
> 
> Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
> 
> BTW, Lorenzo, Rafael, since it's a bugfix, can this be merged into
> 4.10-rc7?

Yes, I thought Rafael picked it up already (I can't see it in
patchwork any longer).

This one from Dan:

https://patchwork.kernel.org/patch/9521003/

should get in -rc7 too, we should have both fixes in before v4.10
is released.

Rafael can you send them both for -rc7 please ?

Thanks,
Lorenzo

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