On Fri, Jul 26, 2019 at 01:00:49PM -0700, Paul Walmsley wrote: > > The RISC-V specifications currently define three virtual memory > translation systems: Sv32, Sv39, and Sv48. Sv32 is currently specific > to 32-bit systems; Sv39 and Sv48 are currently specific to 64-bit > systems. The current kernel only supports Sv32 and Sv39, but we'd > like to start preparing for Sv48. As an initial step, allow the > virtual memory translation system to be selected via kbuild, and stop > the build if an option is selected that the kernel doen't currently > support. > > This patch currently has no functional impact.
It cause the user to be able to select a config which thus won't build. So it is not just useless, which already is a reason not to merge it, but actively harmful, which is even worse. Even if we assume we want to implement Sv48 eventually (which seems to be a bit off), we need to make this a runtime choice and not a compile time one to not balloon the number of configs that distributions (and kernel developers) need to support.