A driver allowing to map any page is like recording a magician from all angles.
The only reasonable usage of such a situation is for the magician him/herself, to study his/her own performance. And even then, it is not usually done that way.
The only reasonable usage of such a situation is for the magician him/herself, to study his/her own performance. And even then, it is not usually done that way.
And while there's better ways to handle it, and it wouldn't pass a design review of mine, it's pretty common to make a driver specific /dev/mem equivalent. For isntance https://forum.xda-developers.com/showthread.php?t=2057818
Any driver for a multiuser OS that essentially bypasses protection mechanisms by the kernel for non-root users is broken, period.
There is no argument about it.