Re: [PATCH v5 2/7] arm64: perf: Avoid PMXEV* indirection

[Stephen Boyd]

Quoting Alexandru Elisei (2020-06-18 03:51:08)
> On 6/17/20 9:11 PM, Stephen Boyd wrote:
> > Quoting Alexandru Elisei (2020-06-17 04:38:46)
> >> From: Mark Rutland <mark.rutland@xxxxxxx>
> >> @@ -433,8 +494,9 @@ static u64 armv8pmu_read_counter(struct perf_event *event)
> >>  
> >>  static inline void armv8pmu_write_evcntr(int idx, u64 value)
> >>  {
> >> -       armv8pmu_select_counter(idx);
> >> -       write_sysreg(value, pmxevcntr_el0);
> >> +       u32 counter = ARMV8_IDX_TO_COUNTER(idx);
> > Might be a good idea to make ARMV8_IDX_TO_COUNTER a static inline
> > function that has a return type of u32. I had to go check the code to
> > make sure it wasn't something larger.
> 
> Architecturally, there are at most 32 counter registers, which would fit in an s8,
> so I don't think type checking would really help us here.

Ok. It would have saved me a few seconds while reading the code, but I
guess if I hold the architecture in my head I'll be ok too.