Re: [Xen-devel] [PATCH 3/3] xen/arm: vpsci: Move PSCI function dispatching from vsmc.c to vpsci.c

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi,

On 31/01/18 11:32, Volodymyr Babchuk wrote:
> > I thought about vpsci.h, but basically you will have only 2 functions 
> > in it and
> > the number of PSCI calls. That's it.
> Is  this really a problem? It is quite natural to find declarations for 
> something.c in something.h. By moving declaration into different file, 
> you are hiding it from anyone who does not carry sacred knowledge (or 
> use grep/cscope, yes).
> And then, when people decide to extend something.c they continue to put 
> declarations into inappropriate.h. Just look at processor.h as a good 
> example. All functions it define are implemented either in traps.c or 
> domain.c. But functions from processor.c are defined in procinfo.h.
> I can tell for sure, that this confuses newbies.
>
>
> > So it is not going to help to update because the header will unlikely 
> > need to
> > change when adding new PSCI call.
> Yes. But at least we can put comment above switch(fid):
>
> /* Please don't forget to update call count in (v)psci.h */
See my answer on my own e-mail I sent few minutes ago. I said I will 
create a the vpsci.h.
> > [...]
> >
> > > > I looked at some implementation of SMCCC and those calls are either not
> > > > handled or the number are not correct.
> > > I agree that *some* implementations can not conform to SMCCC.But, I 
> > > thought
> > > you want Xen to follow standards as close as possible...
> > It is not about cannot conform but only implements partially SMCCC. I 
> > could name
> > ATF for that (yes).
> >
> > So it makes me more confident the call count is not something people 
> > seem to
> > care.
> So, you propose to fix this only when something will trip over this?
No, I am just saying that it is not that important if we get it wrong. 
That number does not tell you anything. You can have 2 functions and 
still does not know where they are (it is not always possible to just 
probe a function ID because they may have side-effect).
Cheers,

--
Julien Grall

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