Commit 2f257a8e authored by James Morse's avatar James Morse Committed by liwei
Browse files

ACPI: processor: Add support for processors described as container packages 

maillist inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8XMTL
CVE: NA

---------------------------------

ACPI has two ways of describing processors in the DSDT. From ACPI v6.5,
5.2.12:

"Starting with ACPI Specification 6.3, the use of the Processor() object
was deprecated. Only legacy systems should continue with this usage. On
the Itanium architecture only, a _UID is provided for the Processor()
that is a string object. This usage of _UID is also deprecated since it
can preclude an OSPM from being able to match a processor to a
non-enumerable device, such as those defined in the MADT. From ACPI
Specification 6.3 onward, all processor objects for all architectures
except Itanium must now use Device() objects with an _HID of ACPI0007,
and use only integer _UID values."

Also see https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control.html#declaring-processors

Duplicate descriptions are not allowed, the ACPI processor driver already
parses the UID from both devices and containers. acpi_processor_get_info()
returns an error if the UID exists twice in the DSDT.

The missing probe for CPUs described as packages creates a problem for
moving the cpu_register() calls into the acpi_processor driver, as CPUs
described like this don't get registered, leading to errors from other
subsystems when they try to add new sysfs entries to the CPU node.
(e.g. topology_sysfs_init()'s use of topology_add_dev() via cpuhp)

To fix this, parse the processor container and call acpi_processor_add()
for each processor that is discovered like this. The processor container
handler is added with acpi_scan_add_handler(), so no detach call will
arrive.

Qemu TCG describes CPUs using processor devices in a processor container.
For more information, see build_cpus_aml() in Qemu hw/acpi/cpu.c and
https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control.html#processor-container-device



Signed-off-by: default avatarJames Morse <james.morse@arm.com>
Tested-by: default avatarMiguel Luis <miguel.luis@oracle.com>
Tested-by: default avatarVishnu Pajjuri <vishnu@os.amperecomputing.com>
Tested-by: default avatarJianyong Wu <jianyong.wu@arm.com>
Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: default avatarliwei <liwei728@huawei.com>
parent 29b33523

drivers/acpi/acpi_processor.c

+22 −0
Original line number Diff line number Diff line
@@ -626,9 +626,31 @@ static struct acpi_scan_handler processor_handler = { 
	},

};



static acpi_status acpi_processor_container_walk(acpi_handle handle,

						 u32 lvl,

						 void *context,

						 void **rv)

{

	struct acpi_device *adev;

	acpi_status status;



	adev = acpi_get_acpi_dev(handle);

	if (!adev)

		return AE_ERROR;



	status = acpi_processor_add(adev, &processor_device_ids[0]);

	acpi_put_acpi_dev(adev);



	return status;

}



static int acpi_processor_container_attach(struct acpi_device *dev,

					   const struct acpi_device_id *id)

{

	acpi_walk_namespace(ACPI_TYPE_PROCESSOR, dev->handle,

			    ACPI_UINT32_MAX, acpi_processor_container_walk,

			    NULL, NULL, NULL);



	return 1;

}