diff options
author | James Morse <james.morse@arm.com> | 2023-01-25 11:58:49 +0000 |
---|---|---|
committer | Russell King (Oracle) <rmk+kernel@armlinux.org.uk> | 2023-11-21 09:43:52 +0000 |
commit | 151a39de9b5a117549e618e54d523178c4f45d6f (patch) | |
tree | 5ca8d6d0042fe24b84a1a79bdc48fa1d13c5f741 | |
parent | 5e5b2ff2a8750fd06e2dd75381d3920dd472ef78 (diff) |
ACPI: processor: Add support for processors described as container packages
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: James Morse <james.morse@arm.com>
-rw-r--r-- | drivers/acpi/acpi_processor.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c index 4fe2ef54088c..6a542e0ce396 100644 --- a/drivers/acpi/acpi_processor.c +++ b/drivers/acpi/acpi_processor.c @@ -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; } |