Hi mpe,
On Wednesday 01 November 2017 06:20 AM, Michael Ellerman wrote:
> Anju T Sudhakar <[email protected]> writes:
>
>> Add ldbar spr to sysfs. The spr will hold thread level In-Memory Collection (IMC)
>> counter configuration data.
> This is missing any justification for why we would want to expose this,
> and in particular why we would make it *writable*.
>
> cheers
Thank you for reviewing the patch.
LDBAR, holds the thread-level counter configuration. Exposing this will help
us to understand the current status of thread-level counters in the system.
Primarily, Bit 0 of ldbar tells whether the counters are enabled or not.
And bit 1 tells the mode (if 0-Accumulation Mode/if 1-Trace Mode).
But regarding the permission, you are right. On a reassessment I think
that the permission
should be read only, because it is possible that we may write an
incorrect value to the ldbar, that is wrong.
So I will change the permission here.
Thanks,
Anju
>
>> diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
>> index 4437c70..f8caee0 100644
>> --- a/arch/powerpc/kernel/sysfs.c
>> +++ b/arch/powerpc/kernel/sysfs.c
>> @@ -485,6 +485,7 @@ SYSFS_PMCSETUP(mmcra, SPRN_MMCRA);
>> SYSFS_SPRSETUP(purr, SPRN_PURR);
>> SYSFS_SPRSETUP(spurr, SPRN_SPURR);
>> SYSFS_SPRSETUP(pir, SPRN_PIR);
>> +SYSFS_SPRSETUP(ldbar, SPRN_LDBAR);
>>
>> /*
>> Lets only enable read for phyp resources and
>> @@ -492,6 +493,7 @@ SYSFS_SPRSETUP(pir, SPRN_PIR);
>> Lets be conservative and default to pseries.
>> */
>> static DEVICE_ATTR(mmcra, 0600, show_mmcra, store_mmcra);
>> +static DEVICE_ATTR(ldbar, 0600, show_ldbar, store_ldbar);
>> static DEVICE_ATTR(spurr, 0400, show_spurr, NULL);
>> static DEVICE_ATTR(purr, 0400, show_purr, store_purr);
>> static DEVICE_ATTR(pir, 0400, show_pir, NULL);
>> @@ -757,6 +759,9 @@ static int register_cpu_online(unsigned int cpu)
>> device_create_file(s, &pmc_attrs[i]);
>>
>> #ifdef CONFIG_PPC64
>> + if (cpu_has_feature(CPU_FTR_ARCH_300))
>> + device_create_file(s, &dev_attr_ldbar);
>> +
>> if (cpu_has_feature(CPU_FTR_MMCRA))
>> device_create_file(s, &dev_attr_mmcra);
>>
>> @@ -842,6 +847,9 @@ static int unregister_cpu_online(unsigned int cpu)
>> device_remove_file(s, &pmc_attrs[i]);
>>
>> #ifdef CONFIG_PPC64
>> + if (cpu_has_feature(CPU_FTR_ARCH_300))
>> + device_remove_file(s, &dev_attr_ldbar);
>> +
>> if (cpu_has_feature(CPU_FTR_MMCRA))
>> device_remove_file(s, &dev_attr_mmcra);
>>
>> --
>> 2.7.4
From 1582822806009262669@xxx Wed Nov 01 00:50:57 +0000 2017
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