Hi Jeremy,
On Wed, Jul 31, 2019 at 10:46:33PM -0500, Jeremy Linton wrote:
> ACPI 6.3 adds a flag to the CPU node to indicate whether
> the given PE is a thread. Add a function to return that
> information for a given linux logical CPU.
>
Apart from few minor nits,
Reviewed-by: Sudeep Holla <sudeep.holla@xxxxxxx>
> Signed-off-by: Jeremy Linton <jeremy.linton@xxxxxxx>
> ---
> drivers/acpi/pptt.c | 54 +++++++++++++++++++++++++++++++++++++++++++-
> include/linux/acpi.h | 5 ++++
> 2 files changed, 58 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
> index 1e7ac0bd0d3a..84718f6cb741 100644
> --- a/drivers/acpi/pptt.c
> +++ b/drivers/acpi/pptt.c
> @@ -540,6 +540,44 @@ static int find_acpi_cpu_topology_tag(unsigned int cpu, int level, int flag)
> return retval;
> }
>
> +/**
> + * check_acpi_cpu_flag() - Determine if CPU node has a flag set
> + * @cpu: Kernel logical CPU number
> + * @rev: The PPTT revision defining the flag
[nit] I would rather put it as minimum PPTT revision that supports the
flag. It aligns with the code too as we are not looking for exact match.
> + * @flag: The flag itself
> + *
> + * Check the node representing a CPU for a given flag.
> + *
> + * Return: -ENOENT if the PPTT doesn't exist, the CPU cannot be found or
> + * the table revision isn't new enough.
> + * 1, any passed flag set
> + * 0, flag unset
> + */
> +static int check_acpi_cpu_flag(unsigned int cpu, int rev, u32 flag)
> +{
> + struct acpi_table_header *table;
> + acpi_status status;
> + u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
> + struct acpi_pptt_processor *cpu_node = NULL;
> + int ret = -ENOENT;
> +
> + status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
> + if (ACPI_FAILURE(status)) {
> + acpi_pptt_warn_missing();
> + return ret;
> + }
> +
> + if (table->revision >= rev)
> + cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
> +
> + if (cpu_node)
> + ret = (cpu_node->flags & flag) != 0;
> +
> + acpi_put_table(table);
> +
> + return ret;
> +}
> +
> /**
> * acpi_find_last_cache_level() - Determines the number of cache levels for a PE
> * @cpu: Kernel logical CPU number
> @@ -604,6 +642,21 @@ int cache_setup_acpi(unsigned int cpu)
> return status;
> }
>
> +/**
> + * acpi_pptt_cpu_is_thread() - Determine if CPU is a thread
> + * @cpu: Kernel logical CPU number
> + *
[nit] If you spin the patch again, you can drop extra line space here.
--
Regards,
Sudeep
