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

Thomas Gleixner
2017-03-01T12:35:13Z

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?

> {
> 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?

> + 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;
}

Thanks,

tglx