On Thu, Jun 12, 2025 at 05:13:33PM +0000, James Morse wrote:
> The PPTT describes CPUs and caches, as well as processor containers.
> The ACPI table for MPAM describes the set of CPUs that can access an MSC
> with the UID of a processor container.
>
> Add a helper to find the processor container by its id, then walk
> the possible CPUs to fill a cpumask with the CPUs that have this
> processor container as a parent.
>
> Signed-off-by: James Morse <james.morse@xxxxxxx>
> ---
> drivers/acpi/pptt.c | 91 ++++++++++++++++++++++++++++++++++++++++++++
> include/linux/acpi.h | 6 +++
> 2 files changed, 97 insertions(+)
>
> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
> index 54676e3d82dd..aaf9b5a26d07 100644
> --- a/drivers/acpi/pptt.c
> +++ b/drivers/acpi/pptt.c
> +
> +/**
> + * acpi_pptt_get_cpus_from_container() - Populate a cpumask with all CPUs in a
> + * processor containers
> + * @acpi_cpu_id: The UID of the processor container.
> + * @cpus The resulting CPU mask.
> + *
> + * Find the specified Processor Container, and fill @cpus with all the cpus
> + * below it.
> + *
> + * Not all 'Processor' entries in the PPTT are either a CPU or a Processor
> + * Container, they may exist purely to describe a Private resource. CPUs
> + * have to be leaves, so a Processor Container is a non-leaf that has the
> + * 'ACPI Processor ID valid' flag set.
> + *
> + * Return: 0 for a complete walk, or an error if the mask is incomplete.
> + */
> +int acpi_pptt_get_cpus_from_container(u32 acpi_cpu_id, cpumask_t *cpus)
> +{
Just noticed now that it is not used anywhere in the series. Can this be added
along with the user later instead ?
--
Regards,
Sudeep
