Re: [PATCH V3 04/10] arm/gic-v3: Parse per-cpu redistributor entry in GICC subtable

[Julien Grall <julien.grall@arm.com>]

Hi Shanker,

On 28/06/16 15:33, Shanker Donthineni wrote:
>
>
> On 06/28/2016 08:51 AM, Shanker Donthineni wrote:
>> Hi Julien,
>>
>>
>> On 06/28/2016 05:40 AM, Julien Grall wrote:
>>> Hello Shanker,
>>>
>>> On 27/06/16 21:33, Shanker Donthineni wrote:
>>>> @@ -1397,6 +1408,36 @@ gic_acpi_parse_madt_distributor(struct
>>> acpi_subtable_header *header,
>>>>   }
>>>>
>>>>   static int __init
>>>> +gic_acpi_parse_cpu_redistributor(struct acpi_subtable_header *header,
>>>> +                                 const unsigned long end)
>>>> +{
>>>> +    struct acpi_madt_generic_interrupt *processor;
>>>> +    u32 size;
>>>> +
>>>> +    processor = (struct acpi_madt_generic_interrupt *)header;
>>>> +    if ( !(processor->flags & ACPI_MADT_ENABLED) )
>>>> +        return 0;
>>>
>>> You did not answer to my question on previous version of this patch.
>>> You said that "Disabled GICC entries should be skipped because its
>>> Redistributor region is not always-on power domain." However from my
>>> understanding, an usable CPU may have his Redistributor in the not
>>> always-on power domain. So the issue would the same, correct?
>>>
>>
>> The gicv3_populate_rdist() is not supposed to read GICR registers if
>> the  the associated hardware GICR block is in power-off state. The CPU
>> accesses to disabled GICR region leads to either a system hang or an
>> unexpected behavior.
>>
>>
> The description of flag ACPI_MADT_ENABLED in ACPI-6.1 says "If zero,
> this processor in unusable, and the operating system support will not
> attempt to use it".

Ok.  The patch looks good to me then.

Regards,

-- 
Julien Grall

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