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From: Michael Ellerman <mpe@ellerman.id.au>
To: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	maddy@linux.vnet.ibm.com, anju@linux.vnet.ibm.com
Subject: Re: [PATCH v2] powerpc/kernel/sysfs: Export ldbar spr to sysfs
Date: Wed, 01 Nov 2017 11:50:04 +1100	[thread overview]
Message-ID: <87h8ue960z.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <1509466547-761-1-git-send-email-anju@linux.vnet.ibm.com>

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

  reply	other threads:[~2017-11-01  0:50 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
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 [this message]
2017-11-07 12:06   ` Anju T Sudhakar

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