Messages in this thread | | | Date | Mon, 5 Oct 2020 18:15:50 -0700 | From | Ricardo Neri <> | Subject | Re: [PATCH 1/4] drivers core: Introduce CPU type sysfs interface |
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On Fri, Oct 02, 2020 at 08:27:41PM -0700, Randy Dunlap wrote: > On 10/2/20 6:17 PM, Ricardo Neri wrote: > > +/** > > + * arch_get_cpu_type() - Get the CPU type number > > + * @cpu: Index of the CPU of which the index is needed > > + * > > + * Get the CPU type number of @cpu, a non-zero unsigned 32-bit number that
Thank you for your feedback Randy!
> Are you sure that @cpu is non-zero?
This is the intent. Maybe it can be reworked to return -EINVAL instead? I gues it is plausible but less likely that an arch defines a type as 0xffffffea;
> > > + * uniquely identifies a type of CPU micro-architecture. All CPUs of the same > > + * type have the same type number. Type numbers are defined by each CPU > > + * architecture. > > + */ > > +u32 __weak arch_get_cpu_type(int cpu) > > +{ > > + return 0; > > +} > > arch_get_cpu_type() in patch 4/4 allows @cpu to be 0.
It should not return 0 if the system does not have X86_FEATURE_HYBRID_CPU. The currently existing CPU types are all non-zero as per the Intel SDM. Am I missing anything?
Thanks and BR, Ricardo
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