Re: [PATCH v2] powerpc/config: powernv_defconfig updates

[Nicholas Piggin <npiggin@gmail.com>]

On Wed, 11 Apr 2018 22:24:06 +1000
Balbir Singh <bsingharora@gmail.com> wrote:

> On Wed, Apr 11, 2018 at 8:42 PM, Nicholas Piggin <npiggin@gmail.com> wrote:
> > On Wed, 11 Apr 2018 20:04:45 +1000
> > Balbir Singh <bsingharora@gmail.com> wrote:
> >  
> >> On Wed, Apr 11, 2018 at 7:12 PM, Nicholas Piggin <npiggin@gmail.com> wrote:  
> >> > For consideration:
> >> >
> >> > * Add IPv6 support built in + additional modules - Because it's 2018 maan.
> >> > * Add DEFERRED_STRUCT_PAGE_INIT - Let's see what breaks.  
> >>
> >> We did not find any benefits with this on a P8 in terms of boot time
> >> with large memory. May be worth reinvestigating  
> >
> > Worth putting in the defconfig just for testing until then?  
> 
> Absolutely!
> 
> >  
> >>  
> >> > * Add PPC_MEMTRACE - Small powernv debugfs driver for getting hardware traces.
> >> > * Add MEMORY_FAILURE - Machine check exceptions can now drive memory failure.  
> >
> >          ^^^^
> > Okay for this one?  
> 
> Yep definitely!
> 
> >  
> >> > * Turn on FANOTIFY - This is the current filesystem notification feature.
> >> > * Turn on SCOM_DEBUGFS - Handy for hardware/firmware debugging, security risk?  
> >>
> >> Yep, should not be in defconfig, IMHO  
> >
> > Why not? Honest question, I hear some things about secure
> > boot when I ask about this option but I'm not quite sure why, or
> > what we are securing here.
> >
> > If the firmware does not want us to mess with scoms, it should
> > restrict the call, no?
> >  
> 
> Yes, firmware definitely should. Do we need inband debugging?

I think it's a matter of convenience when testing and debugging
things. OTOH I haven't used it a great deal myself. Others do
want it if we can just ensure firmware will do the right thing
if we're in some secure configuration.

Thanks,
Nick