On 02/11/2023 12:26 pm, Andrew Cooper wrote: > Seriously, this work started out trying to fix a buggy comment. It > escalated somewhat... Perform some simple tidying. Another dodgy construct spotted while doing this work is #ifdef CONFIG_X86_32 #define BAD_APICID 0xFFu #else #define BAD_APICID 0xFFFFu #endif considering that both of those "bad" values are legal APIC IDs in an x2APIC system. The majority use is as a sentential (of varying types - int, u16 mostly), although the uses for NUM_APIC_CLUSTERS, and safe_smp_processor_id() look suspect. In particular, safe_smp_processor_id() *will* malfunction on some legal CPUs, and needs to use -1 (32 bits wide) to spot the intended error case of a bad xAPIC mapping. However, it's use in amd_pmu_cpu_starting() from topology_die_id() looks broken. Partly because the error handling is (only) a WARN_ON_ONCE(), and also because nb->nb_id's sentinel value is -1 of type int. I suspect there's a lot of cleaning to be done here too. ~Andrew
