[uClinux-dev] Re: Porting Linux programs to uClinux and other

[Gavin Lambert]

Quoth Mike Frysinger:
> while some processors lack an MMU, then do not lack an MPU (memory
> protection unit).  for example, the Blackfin processor has an MPU which
> means the Blackfin Linux port can (and does) prevent user space from
> accessing peripherals.  we can (and have an experimental/in-development
> patch) also protect processes from other processes and kernel space
> from user space, but the overhead here seems to be noticeable since the
> hardware table can only contain 16 entries.

Many Coldfire CPUs also support memory protection, although last time I
checked the kernel didn't enforce it.