Re: [PATCH v2 3/4] acpi: Fix the check handle in case of declaring processors using the Device operator

Dou Liyang
2017-03-02T08:12:37Z

Hi tglx,

At 03/01/2017 07:12 PM, Thomas Gleixner wrote:
> On Mon, 20 Feb 2017, Dou Liyang wrote:
>
>> In ACPI spec, we can declare processors using both Processor and
>> Device operator. And before we use the ACPI table, we should check
>> the correctness for all processors in ACPI namespace.
>>
>> But, Currently, the check handle is just include only the processors
>> which are declared by Processor operator. It misses the processors
>> declared by Device operator.
>>
>> The patch adds the case of Device operator.
>
> See the comments in the previous mails. They apply here as well.
>
> Though this changelog is actively confusing. The subject line says:
>
> acpi: Fix the check handle in case of declaring processors using the Device
> operator
>
> Aside of being a way too long subject, it suggests that there is just a
> missing check for the case where a processor is declared via the Device
> operator. But that's not what the patch is doing.
>
> It implements the distinction between Device and Processor operator, which
> is missing in acpi_processor_ids_walk() right now.
>
> So the proper changelog (if I understand the patch correctly) would be:
>
> Subject: acpi/processor: Implement DEVICE operator for processor enumeration
>
> ACPI allows to declare processors either with the PROCESSOR or with the
> DEVICE operator. The current implementation handles only the PROCESSOR
> operator.
>
> On a system which uses the DEVICE operator for processor enumeration the
> evaluation fails.
>
> Check for the ACPI type of the ACPI handle and evaluate PROCESSOR and
> DEVICE types seperately.
>
> Hmm?
>

Yes, you are right. I didn't explain clearly.
I will modify in my next version.

>> {
>> acpi_status status;
>> + acpi_object_type acpi_type;
>> + unsigned long long uid;
>> union acpi_object object = { 0 };
>> struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
>>
>> - status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
>> - if (ACPI_FAILURE(status))
>> - acpi_handle_info(handle, "Not get the processor object\n");
>> - else
>> - processor_validated_ids_update(object.processor.proc_id);
>> + status = acpi_get_type(handle, &acpi_type);
>
> Shouldn't the status be checked here?

oops, Yes. Need to be checked.

>
>> + switch (acpi_type) {
>> + case ACPI_TYPE_PROCESSOR:
>> + status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
>> + if (ACPI_FAILURE(status))
>> + acpi_handle_info(handle, "Not get the processor object\n");
>> + else
>> + processor_validated_ids_update(
>> + object.processor.proc_id);
>> + break;
>> + case ACPI_TYPE_DEVICE:
>> + status = acpi_evaluate_integer(handle, "_UID", NULL, &uid);
>> + if (ACPI_FAILURE(status))
>> + return false;
>> + processor_validated_ids_update(uid);
>> + break;
>> + default:
>> + return false;
>
> This is inconsistent vs. the failure handling in the PROCESSOR and DEVICE
> case and the default case does not give any information either.
>
> What about this:
>
> switch (acpi_type) {
> case ACPI_TYPE_PROCESSOR:
> status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
> if (ACPI_FAILURE(status))
> goto err;
> uid = object.processor.proc_id;
> break;
>
> case ACPI_TYPE_DEVICE:
> status = acpi_evaluate_integer(handle, "_UID", NULL, &uid);
> if (ACPI_FAILURE(status))
> goto err;
> break;
> default:
> goto err;
> }
>
> processor_validated_ids_update(uid);
> return true;
>
> err:
> acpi_handle_info(handle, "Invalid processor object\n");
> return false;
> }
>

Looks good than mine.

Thanks,
Liyang.

> Thanks,
>
> tglx
>
>
>