On Thu, Feb 13, 2020 at 02:09:17PM +1100, Alexey Kardashevskiy wrote: > > > On 12/02/2020 16:43, David Gibson wrote: > > On Mon, Feb 03, 2020 at 02:29:38PM +1100, Alexey Kardashevskiy wrote: > >> At the moment we enforce 64bit mode on a CPU when reset. This does not > >> make difference as SLOF or Linux set the desired mode straight away. > >> However if we ever boot something other than these two, > >> this might not work as, for example, GRUB expects the default MSR state > >> and does not work properly. > >> > >> This removes setting MSR_SF from the PPC CPU reset. > > > > Hrm. This is in the core cpu model so it doesn't just affect pseries, > > but powernv (and theoretically others) as well. Generally the cpu > > model should have the bare metal behaviour, and we can override it in > > the pseries machine if necessary. > > > > So for a bare metal POWER system, what mode do we start in? I'm > > guessing it probably doesn't matter in practice, since the skiboot > > firmware also probably does a mode set on entry, but it'd be nice to > > get this right in theory. > > > Huh. "Figure 65. MSR setting due to interrupt" of PowerISA 3.0 says > "The SF bit is set to 1" so after all the existing behavior is correct > and my patch is just wrong. Cool.
Well, I guess SF after interrupt isn't *necessarily* the same as SF at reset, but it's a good place to start. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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