af36ae12b0
Before it was first add_ref'ed by `borrow_frame_enforce_rw_allocated`, manually and then by `allocated_shared_one_page`. Now it is only done by `borrow_frame_enforce_rw_allocated` and does not get unref-ed as take() is called on the returned `RaiiFrame`. Now the page is manually mapped and an `Allocated` type grant is constructed (synonymous to `MAP_PRIVATE`). Before by using `allocated_shared_one_page` an `AllocatedShared` provided grant was constructed (synonymous to `MAP_SHARED`), which was wrong as the TCB would've not got CoW-ed after fork(), making the Tcb malformed. Signed-off-by: Anhad Singh <andypython@protonmail.com>