RPi3 not using SMP?

[John F Carr]

> On Feb 8, 2020, at 17:28 , Mark Millard via freebsd-arm <freebsd-arm at freebsd.org> wrote:
> 
> 
> FYI: I ran into a note on the web reporting that for the
> RPi4:
> 
> The SoC does not seem to feature a secure memory controller of any kind, so portions of DRAM can’t be protected properly from the Non-secure world.
> 
> ( https://trustedfirmware-a.readthedocs.io/en/latest/plat/rpi4.html#tf-a-port-design )
> 

I don't think that's important.  Secure memory is meant to protect against malicious privileged code and we're probably dealing only with buggy privileged code.

It may be possible to map the device tree pages read only.  That protects against bad pointers and stores that would otherwise clobber data.  The kernel would crash instead of corrupting memory.  And then you have a much simpler debugging problem.