Messages in this thread | | | Subject | Re: [PATCH 1/4] drivers core: Introduce CPU type sysfs interface | From | Randy Dunlap <> | Date | Fri, 9 Oct 2020 20:14:50 -0700 |
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On 10/5/20 6:15 PM, Ricardo Neri wrote: > 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;
You lost me here.
>> >>> + * 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?
@cpu is a cpu index, not a cpu type.
-- ~Randy
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