* [PATCH v2] powerpc/kernel/sysfs: Export ldbar spr to sysfs
@ 2017-10-31 16:15 Anju T Sudhakar
2017-11-01 0:50 ` Michael Ellerman
0 siblings, 1 reply; 3+ messages in thread
From: Anju T Sudhakar @ 2017-10-31 16:15 UTC (permalink / raw)
To: mpe; +Cc: linuxppc-dev, linux-kernel, maddy, anju
Add ldbar spr to sysfs. The spr will hold thread level In-Memory Collection (IMC)
counter configuration data.
Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
---
arch/powerpc/kernel/sysfs.c | 8 ++++++++
1 file changed, 8 insertions(+)
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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] powerpc/kernel/sysfs: Export ldbar spr to sysfs
2017-10-31 16:15 [PATCH v2] powerpc/kernel/sysfs: Export ldbar spr to sysfs Anju T Sudhakar
@ 2017-11-01 0:50 ` Michael Ellerman
2017-11-07 12:06 ` Anju T Sudhakar
0 siblings, 1 reply; 3+ messages in thread
From: Michael Ellerman @ 2017-11-01 0:50 UTC (permalink / raw)
To: Anju T Sudhakar; +Cc: linuxppc-dev, linux-kernel, maddy, anju
Anju T Sudhakar <anju@linux.vnet.ibm.com> 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
> 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
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] powerpc/kernel/sysfs: Export ldbar spr to sysfs
2017-11-01 0:50 ` Michael Ellerman
@ 2017-11-07 12:06 ` Anju T Sudhakar
0 siblings, 0 replies; 3+ messages in thread
From: Anju T Sudhakar @ 2017-11-07 12:06 UTC (permalink / raw)
To: Michael Ellerman; +Cc: linuxppc-dev, linux-kernel, maddy
Hi mpe,
On Wednesday 01 November 2017 06:20 AM, Michael Ellerman wrote:
> Anju T Sudhakar <anju@linux.vnet.ibm.com> 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
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-10-31 16:15 [PATCH v2] powerpc/kernel/sysfs: Export ldbar spr to sysfs Anju T Sudhakar
2017-11-01 0:50 ` Michael Ellerman
2017-11-07 12:06 ` Anju T Sudhakar
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