[U-Boot] [PATCH 1/3] PPC 85xx: Detect e500v2 / e500mc during runtime

[Alexander Graf]

On 21.01.2014, at 03:25, Scott Wood <scottwood at freescale.com> wrote:

> On Sun, 2014-01-19 at 16:19 +0100, Alexander Graf wrote:
>> With the qemu-ppce500 machine type we can run the same board with
>> either an e500v2 or an e500mc core plugged in.
>> 
>> This means that the IVOR setup can't be based on compile time decisions,
>> so instead we have to do a runtime check which CPU generation we're
>> running on.
> 
> Is this really the only place where you ran into this?

Yup. At least the only place where the difference actually matters for a VM.

> Also consider that you'll be adding extra size, and some of our 85xx
> targets are pretty close to the limit as is (though at least this code
> isn't used in SPLs).
> 
> I guess nobody ever bothered to set IVORs for e6500-specific exceptions.
> 
> For that matter, I don't see why we need this code at all.  These aren't
> the addresses that U-Boot keeps its exception vectors at; it's setting
> them up for the OS, apparently trying to imitate some other type of
> book3e chip that has fixed ivors.  Apparently U-Boot has done this only
> since 2009 (commit 26f4cdba6b51deab4ec99d60be381244068ef950), so it's
> not even something that an OS could depend on (and certainly Linux
> doesn't).  So I don't see the point.

Kumar, do you remember why you put this in? Was it only for prototyping purposes?

I certainly wouldn't mind removing the whole thing altogether.


Alex