On 3/5/25 10:01, David Gibson wrote:
On Mon, Feb 24, 2025 at 03:39:41PM +0530, Ayush Singh wrote:
On 2/24/25 14:07, Geert Uytterhoeven wrote:
Hi Ayush,
On Sat, 22 Feb 2025 at 21:14, Ayush Singh <ayush@xxxxxxxxxxxxxxx> wrote:
# Challenges
## Security
The concerns regarding security seemed to show up in the other
proposals. There was a proposal to have a devicetree property to
allow/deny the application of overlays in some nodes, with default being
deny. Was it insufficient?
This is the most important issue: using DT overlays, you can change
about anything. There is no protection yet to limit this to e.g. the
expansion connectors on your board.
This is what the various WIP "connector" abstractions are trying
to solve.
Thanks for clarifying. However, as I mentioned above, there are usecases for
dynamic overlays outside of connectors. Specifically, for the usecase of
connecting random sensors to board pins. I do agree that any fairly well
specified connector should probably have it's own drivers rather than using
a generic userspace API.
I'm not sure that's just due to an insuffuciently broad conception of
what a "connector" might be. Note that to justify a dynamic overlay
interface specifically you need to have *both*
1) a need to update *anywhere* in the device tree and
2) to do so at runtime, under userspace control
It's kind of hard to see why you'd need (2) in cases that don't at
some physical level involve a "connector".. in which case (1) is hard
to justify.
How are these sensors being connected to random board pins? If it's
because those pins are exposed on some header, then it seems like it
ought to fall within the definition of a connector. If someone is
just soldering onto them, it seems like an semi-permanent change that
would be better handled at boot time.
I see. It seems my perception of connector was a bit too narrow.
Certainly, treating the whole board header as a connector would
certainly be a better solution, since it will also allow great control
using a dedicated driver. Thanks for the insight.
Ayush Singh
