On Thu, 10 Aug 2023 at 05:42, Schimpe, Christina christina.schimpe@intel.com wrote:
We don't have any LAM support in GDB yet, we are just working on it. We currently rely on that feature, but could still change it. We don't necessarily require /proc/PID/mem to support tagged addresses.
ARM's TBI support in GDB does not rely on /proc/PID/mem to support tagged addresses AFAIK.
Ahh. That would explain why nobody noticed.
I do wonder if perhaps /proc/<pid>/mem should just match the real addresses (ie the ones you would see in /proc/<pid>/maps).
The main reason GUP does the untagging is that obviously people will pass in their own virtual addresses when doing direct-IO etc.
So /proc/<pid>/mem is a bit different.
That said, untagging does make some things easier, so I think it's probably the right thing to do.
Linus