Arjan van de Ven wrote:Thomas Hellström wrote:Hmm, I'm not sure I follow you here. Are you saying that it's illegal to have an NP mapping of a page (which, If I understand it correctly, means no mapping at all) at the same time as you have a, say user-space WC mapping pointing to the same physical page?Given this problem, the previously mentioned use-case, and the fact that we mostly really use user-space mappings,
Is there a possibility we could add the following functions to Dave's patch (provided they would work as intended, of course, namely invalidate / bring back the kernel mapping).
sadly there are multiple mappings, both in theory and practice.
Especially the _np / _p functions specifically work on only the mapping you specify.
For this to work we would need to somehow make a "mark all mappings NP, but please only do the kernel ones" kind of thing.
The semantics of that are... lets say messy at best.
I was under the impression that calling CPA on the kernel mapping of that page would do the rest?