Re: [PATCH net] net: fman: Use physical address for userspace interfaces

From: Andrew Lunn
Date: Tue Oct 18 2022 - 13:22:10 EST


On Mon, Oct 17, 2022 at 12:28:06PM -0400, Sean Anderson wrote:
> For whatever reason, the address of the MAC is exposed to userspace in
> several places. We need to use the physical address for this purpose to
> avoid leaking information about the kernel's memory layout, and to keep
> backwards compatibility.

How does this keep backwards compatibility? Whatever is in user space
using this virtual address expects a virtual address. If it now gets a
physical address it will probably do the wrong thing. Unless there is
a one to one mapping, and you are exposing virtual addresses anyway.

If you are going to break backwards compatibility Maybe it would be
better to return 0xdeadbeef? Or 0?

Andrew