Re: [PATCH v2 5/5] powerpc/configs: Disable SCOM_DEBUGFS in powernv_defconfig

[Andrew Donnellan <ajd@linux.ibm.com>]

On 9/5/19 3:54 pm, Andrew Donnellan wrote:
> On 9/5/19 3:37 pm, Nicholas Piggin wrote:
>> Andrew Donnellan's on May 9, 2019 3:11 pm:
>>> SCOM_DEBUGFS is really not needed for anything other than low-level
>>> hardware debugging.
>>>
>>> opal-prd uses its own interface (/dev/prd) for SCOM access, so it 
>>> doesn't
>>> need SCOM_DEBUGFS.
>>>
>>> At some point in the future we'll introduce a debug config fragment 
>>> where
>>> this can go instead.
>>
>> That doesn't really explain why you want to disable it. It is useful
>> for low level hardware debugging, I added it.
>>
>> obscurity^Wsecurity?
> 
> Mostly just a general feeling that it's not something we need to have by 
> default. Security-wise, PRD still provides SCOM access, though we are 
> going to look at how we can further lock that down. Shrinks the build by 
> only a few kilobytes...
> 
> mpe said he's planning on adding a debug.config where we can shift stuff 
> like this, and if/when we do that I would like to see this moved there, 
> but perhaps this patch can wait until then. I'll let mpe decide.
> 

mpe do you have thoughts on this? I would like to see at least the rest 
of this series merged.


Andrew


> 
> Andrew
> 
> 
>>
>>>
>>> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
>>> ---
>>> v1->v2:
>>> - new patch
>>> ---
>>>   arch/powerpc/configs/powernv_defconfig | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/arch/powerpc/configs/powernv_defconfig 
>>> b/arch/powerpc/configs/powernv_defconfig
>>> index ef2ef98d3f28..d5a6608cb2e0 100644
>>> --- a/arch/powerpc/configs/powernv_defconfig
>>> +++ b/arch/powerpc/configs/powernv_defconfig
>>> @@ -38,7 +38,7 @@ CONFIG_MODULE_UNLOAD=y
>>>   CONFIG_MODVERSIONS=y
>>>   CONFIG_MODULE_SRCVERSION_ALL=y
>>>   CONFIG_PARTITION_ADVANCED=y
>>> -CONFIG_SCOM_DEBUGFS=y
>>> +# CONFIG_SCOM_DEBUGFS is not set
>>>   CONFIG_OPAL_PRD=y
>>>   CONFIG_PPC_MEMTRACE=y
>>>   # CONFIG_PPC_PSERIES is not set
>>> -- 
>>> 2.20.1
>>>
>>>
>>
> 

-- 
Andrew Donnellan              OzLabs, ADL Canberra
ajd@linux.ibm.com             IBM Australia Limited