On Fri, Sep 29, 2023 at 2:54 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > On Fri, Sep 29, 2023 at 09:11:58PM +0000, Sami Tolvanen wrote: > > ARCH_MMAP_RND_BITS_MAX is based on Sv39, which leaves a few > > potential bits of mmap randomness on the table if we end up enabling > > 4/5-level paging. Update mmap_rnd_bits_max to take the final address > > space size into account. This increases mmap_rnd_bits_max from 24 to > > 33 with Sv48/57. > > > > Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> > > I like this. Is RISCV the only arch where the paging level can be chosen > at boot time? I haven't seen this elsewhere, but I also haven't looked at all the other architectures that closely. arm64 does something interesting with ARM64_VA_BITS_52, but I think we can still handle that in Kconfig. Sami
