svn commit: r307626 - head/sys/ufs/ffs

[Adrian Chadd]

On 13 November 2016 at 08:15, Konstantin Belousov <kostikbel at gmail.com> wrote:

> Sparc64 also has the aliasing issue, and AFAIR sparc64 pmap does allow
> more than one mapping of the same page at conflicting ('differently
> colored') addresses.  But indeed, each mapping (not only the managed
> mappings) are tracked, and all mappings are demoted to uncached if
> conflict is created.

Hm, so where's that been happening? Why hasn't this happened in the
mips32 world until this commit?

>> It'd be neat to see this happen; I'm not sure who would really do it.
>> It's tricky to get right.  We may support other architectures that
>> have complete or partial solutions to this, but I deliberately don't
>> know about them.  Stare at code dealing with VIPT ARM systems, or pmap
>> on other BSDs that have sunk more effort into all the edge cases of
>> VIPT MIPS systems.
> For arm, only arm v4 pmap deals with VIPT aliasing.  Arm v6 assumes that
> the system is free from that bug.




-adrian