Date: Sun, 13 Nov 2016 10:42:44 -0800 From: Adrian Chadd <adrian.chadd@gmail.com> To: Konstantin Belousov <kostikbel@gmail.com> Cc: Juli Mallett <jmallett@freebsd.org>, Warner Losh <wlosh@bsdimp.com>, Warner Losh <imp@bsdimp.com>, "freebsd-mips@freebsd.org" <freebsd-mips@freebsd.org> Subject: Re: svn commit: r307626 - head/sys/ufs/ffs Message-ID: <CAJ-VmomG6e8WVyyuqAkC20fwZ5wX2hnwSE7T4r%2BTSDF%2BOzLCNQ@mail.gmail.com> In-Reply-To: <20161113161548.GK54029@kib.kiev.ua> References: <201610191109.u9JB9TTC002727@repo.freebsd.org> <CAJ-Vmom5rYe89m7bch4qoHHq3X2e67pPk_7G2aRGrjSPNp5mzg@mail.gmail.com> <20161113065851.GD54029@kib.kiev.ua> <CANCZdfreg9wD-2pdGtzgeO86BptSE4M7LnLFTC09K3RHyHR8cQ@mail.gmail.com> <20161113071911.GF54029@kib.kiev.ua> <CANCZdfpC6smeNSPKzpbX8aAnF8CZ%2BSEFQmQ74jqvWUVXrttM%2BQ@mail.gmail.com> <20161113075557.GH54029@kib.kiev.ua> <71C512CD-0FB6-40D8-B46C-30467A245693@bsdimp.com> <CACVs6=_zmjJhMzmyFGJGHK1RAguQ_fZUcd94ZEmVEnTXBiOSdQ@mail.gmail.com> <20161113161548.GK54029@kib.kiev.ua>
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On 13 November 2016 at 08:15, Konstantin Belousov <kostikbel@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
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