On 07.05.2013 [07:37:08 +1000], Benjamin Herrenschmidt wrote: > On Mon, 2013-05-06 at 09:38 -0500, Ryan Arnold wrote: > > My understanding was that these bits being 'on' is an indication of > > what features the hardware supports (or what the kernel emulates) and > > a not an indication of whether that facility is currently enabled or > > not. If the hardware supports a particular feature but it is not > > enabled I'd expect that user-space usage of that feature would cause > > the kernel to trap on a facility availability exception (which is how > > Altivec/VMX is implemented, being defaulted to turned off). > > Right but the discussion is about whether we should expose the bits > when the kernel doesn't have the ability to handle the feature :-) > > IE. We need to remove the HTM feature if the kernel is compiled without > transactional memory support. > > Similarily, Nish, you may need to check that we remove those bits if > pHyp has the partition in a mode that doesn't support them (P7 > compatibility for example) for migration purposes.
Yep, I'll need to talk with Mikey about this part. Will be a follow-on patch if needed. Minimally, the bit defines will stay the same, which is the important part to get going right now. Thanks, Nish _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
