On Mon, Nov 23, 2020 at 4:29 PM Dmitry Safonov <d...@arista.com> wrote: > > Instead of having every architecture to define vdso_base/vdso_addr etc, > provide a generic mechanism to track vdso_base for landing in userspace. > It'll minimize per-architecture difference, the number of callbacks to > provide. > > Originally, it started from thread [1] where the need for .close() > callback on vm_special_mapping was pointed, this generic code besides > removing duplicated .mremap() callbacks provides a cheaper way to > support munmap() on vdso mappings without introducing .close() callbacks > for every architecture (with would bring even more code duplication).
I admit I'm slightly dubious about passing in the old vma and comparing its start address as opposed to using some more explicit "is this the vdso" check, but I guess I'm okay with that.
