On 6/20/2025 11:24 AM, Dave Hansen wrote: > On 6/20/25 11:14, Sohil Mehta wrote: >> @Dave Hansen, you had suggested separating out the SMAP/LASS AC toggle >> functions. But, the difference in usage between both of them seems very >> subtle. Could this be easily misused? > > Logically there are two completely different things: > > 1. Touching userspace > 2. Touching the lower half of the address space > > If it's only userspace in the lower half of the address space, then > there's no controversy. But the problem obviously occurs when you want > to touch kernel mappings in the lower half of the address space. > Makes sense. If we decide to go this way, we should capture some of this thinking into the kernel comments. I find the current wording very ambiguous. > I want to preserve the "stac/clas" meaning as just "touch userspace". > > The new functions should be for "touch the lower half of the address > space" alone. Maybe it should be: > > lass_disable_enforcement() > lass_enable_enforcement() > > The only downside of not having stac/clac in the names is that it's not > obvious that they have an impact on SMAP because they're named to be > LASS-only. Yeah, the reverse is also true, where the SMAP specific clac()/stac() toggle LASS enforcement :)
