Hi Jeremy, Few nits below. Also, I had a look at the other PPTT processor flags that were introduced in 6.3, and the only other one being used is ACPI_LEAF_NODE in acpi_pptt_leaf_node(). However that one already has a handle on the table header, so the check_acpi_cpu_flag() isn't of much help there. I don't believe the other existing flags will benefit from the helper since they are more about describing the PPTT tree, but I think it doesn't hurt to keep it around for potential future flags. On 14/06/2019 23:31, Jeremy Linton wrote: [...] > @@ -517,6 +517,43 @@ 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 > + * @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. > + * Otherwise returns flag value > + */ Nit: strictly speaking we're not returning the flag value but its mask applied to the flags field. I don't think anyone will care about getting the actual flag value, but it should be made obvious in the doc: -ENOENT if ... 0 if the flag isn't set > 0 if it is set. [...] > @@ -581,6 +618,21 @@ 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: extra newline > + * Return: 1, a thread > + * 0, not a thread > + * -ENOENT ,if the PPTT doesn't exist, the CPU cannot be found or > + * the table revision isn't new enough. > + */ > +int acpi_pptt_cpu_is_thread(unsigned int cpu) > +{ > + return check_acpi_cpu_flag(cpu, 2, ACPI_PPTT_ACPI_PROCESSOR_IS_THREAD); > +} > + > /** > * find_acpi_cpu_topology() - Determine a unique topology value for a given CPU > * @cpu: Kernel logical CPU number > @@ -641,7 +693,6 @@ int find_acpi_cpu_cache_topology(unsigned int cpu, int level) [...]