On Tue, Jan 25, 2022 at 01:21:47PM +0000, Marc Zyngier wrote:
Mark Brown broonie@kernel.org wrote:
OK, I'll remove the defensiveness here. FGT is mandatory from v8.6 and SME is a v9 feature so people shouldn't build a SME implementation that lacks FGT.
Can you then please make it that SME doesn't get enabled at all if FGT isn't present? It would also be good to have a clarification in the architecture that it isn't allowed to build SME without FGT (specially given that v9.0 is congruent to v8.5, and thus doesn't have FGT).
Right, this should be handled by the time the full spec is published - it's an issue people are aware of and it's not something that should ever get built.
It would be good to explicitly handle the dependency in the cpufeature stuff, we'll have other issues like this, but I'd like to handle that separately since at first look doing it properly is a bit of surgery on cpufeature and the series is already rather large.