Re: perf usage of arch/arm64/include/asm/cputype.h

[Yicong Yang <yangyicong@huawei.com>]

On 2025/6/16 21:07, Leo Yan wrote:
> On Mon, Jun 16, 2025 at 09:54:43AM +0000, Shameerali Kolothum Thodi wrote:
> 
> [...]
> 
>>>> -bool is_midr_in_range_list(struct midr_range const *ranges) -{
>>>> -	while (ranges->model)
>>>> -		if (is_midr_in_range(ranges++))
>>>> -			return true;
>>>>   	return false;
>>>>   }
> 
>>> Looks ok to me.
>>>
>>> You could do it with slightly less churn on the kernel side if you keep the
>>> function name and arguments the same there. There's only one usage in
>>> Perf so that one could be renamed and have the midr argument added back
>>> in.
>>
>> +1.
>>
>> Can we use a separate one for perf here, something like below(untested)?
> 
> Thanks for working on this. Agreed.
> 
>> --- a/tools/perf/util/arm-spe.c
>> +++ b/tools/perf/util/arm-spe.c
>> @@ -842,6 +842,18 @@ static void arm_spe__synth_memory_level(const
>> struct arm_spe_record *record,
>>                 data_src->mem_lvl |= PERF_MEM_LVL_REM_CCE1;
>>  }
>>
>> +static bool is_perf_midr_in_range_list(u32 midr, struct midr_range
>> const *ranges)
>> +{
>> +       while (ranges->model) {
>> +               if (midr_is_cpu_model_range(midr, ranges->model,
>> +                                           ranges->rv_min, ranges->rv_max)) {
>> +                       return true;
>> +               }
>> +               ranges++;
>> +       }
>> +       return false;
>> +}
> 
> Maybe we can make it more general. For example, move this function into
> a common header such as tools/perf/arch/arm64/include/cputype.h. Then,
> util/arm-spe.c can include this header.
> 

ok this sounds just like as before except rename the midr check function and modify the
users in perf. will do in below steps:
- move cpu_errata_set_target_impl()/is_midr_in_range_list() out of cputype.h
  since they're only used in the kernel with errata information
- introduce is_target_midr_in_range_list() in cputype.h to test certain MIDR
  is within the ranges. (is_perf_midr_in_range_list() only make sense in
  userspace and is a bit strange to me in a kernel header). maybe reimplement
  is_midr_in_range_list() with is_target_midr_in_range_list() otherwise there's
  no users in kernel
- copy cputype.h to userspace and make users use new is_target_midr_in_range_list()

this will avoid touching the kernel too much and userspace don't need to implement
a separate function.

Thanks.