Multiple virtual mappings considered harmful on ARM

[M. Warner Losh]

In message: <494BAA90.7000801 at semihalf.com>
            Grzegorz Bernacki <gjb at semihalf.com> writes:
: 2. Root cause.
...
: So we end up with at least two virtual addresses for each page.
...
: 4. More general solution.
: This is the second time we indentified a problem of the same nature related to
: multiple virtual mapping on ARM, and are wondering about some more general
: solution that would prevent us from such problems (very subtle and hard to
: nail down) in the future. We were thinking at least about an extension to
: DIAGNOSTIC that would detect such attempts or so. Any other suggestions or
: comments welcome.

I think this is an excellent idea.  MIPS will need this too, since it
too suffers from the virtual aliasing problem.

Warner