On Mon, 15 Feb 2021 at 20:30, Pavel Tatashin <pasha.tatas...@soleen.com> wrote: > > > Can't we simply use signed arithmetic here? This expression works fine > > if the quantities are all interpreted as s64 instead of u64 > > I was thinking about that, but I do not like the idea of using sign > arithmetics for physical addresses. Also, I am worried that someone in > the future will unknowingly change it to unsigns or to phys_addr_t. It > is safer to have start explicitly set to 0 in case of wrap.
memstart_addr is already a s64 for this exact reason. Btw, the KASLR check is incorrect: memstart_addr could also be negative when running the 52-bit VA kernel on hardware that is only 48-bit VA capable.
