On Wed, Dec 5, 2018 at 12:52 AM Nadav Amit <namit@xxxxxxxxxx> wrote: > > When module memory is about to be freed, there is no apparent reason to > make it (and its data) executable, but that's exactly what is done > today. This is not efficient and not secure. > > There are various theories why it was done, but none of them seem as > something that really require it today. nios2 uses kmalloc for module > memory, but anyhow it does not change the PTEs of the module memory. In > x86, changing vmalloc'd memory mappings also modifies the direct mapping > alias, but the NX-bit is not modified in such way. > > So let's remove it. Andy suggested that the changes of the PTEs can be > avoided (excluding the direct-mapping alias), which is true. However, > in x86 it requires some cleanup of the contiguous page allocator, which > is outside of the scope of this patch-set. > I'm okay with this, but I'd like to see Rick's stuff get rebased on top of it and clean it up for real.
