Re: [PATCH] MIPS: Add CPU option reporting to /proc/cpuinfo

[Hauke Mehrtens <hauke@hauke-m.de>]

On 12/25/18 10:35 PM, Kevin 'ldir' Darbyshire-Bryant wrote:
> 
> 
>> On 24 Dec 2018, at 14:43, Kevin 'ldir' Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk> wrote:
>>
>>
>>
>>> On 24 Dec 2018, at 13:42, Hauke Mehrtens <hauke@hauke-m.de> wrote:
>>>
>> <snip>
>>> Hi Kevin,
>>>
>>> Normally you should not deactivate any features in cpu-feature-overrides.h which are supported by the CPU, when you do not define any thing the kernel will use auto detection.
>>>
>>> I think we should use the cpu_has_foo features as these are the features which could be used by user space applications, if it is only accidentally deactivated by the kernel, which should not happen, it could be that this feature is not fully set up by the kernel and will not work.
>>>
>>> Hauke
>>
>> Fair enough.
> 
> Tried your patch and discovered you need to wrap the cpu_has_mipsmt_pertccounters:
> 
> +#ifdef CONFIG_MIPS_PERF_SHARED_TC_COUNTERS
> +      if (cpu_has_mipsmt_pertccounters)
> +              seq_printf(m, "%s", " mipsmt_pertccounters");
> +#endif
> 
> otherwise when building for archer c7 v2 (74kc) in openwrt this happens:
> 
> arch/mips/kernel/proc.c: In function 'show_cpuinfo':
> arch/mips/kernel/proc.c:245:6: error: 'cpu_has_mipsmt_pertccounters' undeclared (first use in this function); did you mean 'can_use_mips_counter'?
>    if (cpu_has_mipsmt_pertccounters)
>        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
>        can_use_mips_counter
> 
> 
> Cheers,
> 
> Kevin D-B
> 
> 012C ACB2 28C6 C53E 9775  9123 B3A2 389B 9DE2 334A
> 
Hi Kevin,

I do not see any condition based on CONFIG_MIPS_PERF_SHARED_TC_COUNTERS 
in arch/mips/include/asm/cpu-features.h, which kernel version did you 
use to test this patch? cpu_has_mipsmt_pertccounters was introduced 
between kernel 4.14 and 4.19, so it is not available in older kernel 
versions.

Hauke