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The ACPI specification v6.5, sTable 5.158: Processor Structure Flags states that: """ The processor container will have a matching ID value returned through the _UID method. As not every pro- cessor hierarchy node structure in PPTT may have a matching processor container, this flag indicates whether the ACPI pro- cessor ID points to valid entry. Where a valid entry is possible the ACPI Processor ID and _UID method are mandatory. """ And in: Table 5.157: Processor Hierarchy Node Structure """ If the processor structure rep- resents a group of associated processors, the structure might match a processor container in the name space. In that case this entry will match the value of the _UID method of the as- sociated processor container. Where there is a match it must be represented. The flags field, described in Processor Struc- ture Flags, includes a bit to describe whether the ACPI pro- cessor ID is valid. """ The DynamicTablesPkg currently creates a processor container: - in the SSDT CPU Topology generator, with the _HID=ACPI0010, and with a valid _UID - in the PPTT table for each CM_ARCH_COMMON_PROC_HIERARCHY_INFO structure. Thus: - all the processor containers should have the VALID bit set if the SSDT CPU Topology table is present. - if the SSDT CPU Topology table is present, but there is no PPTT table, then the state of the VALID bit is ignored. A contrario, an example where the VALID bit should not be set would be if: - the SSDT CPU Topology generator is absent - no processor container is created in the SSDT topology, i.e. if a flat hierarchy is created. Signed-off-by: Pierre Gondois <pierre.gondois@arm.com> |
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| .. | ||
| Arm | ||
| X64 | ||
| SsdtCpuTopologyGenerator.c | ||
| SsdtCpuTopologyGenerator.h | ||
| SsdtCpuTopologyLib.inf | ||