Re: TLB tiredown by ASID bump

[Eduardo Horvath <eeh%NetBSD.org@localhost>]

On Fri, 7 Jan 2011, Toru Nishimura wrote:

> Eduardo Horvath said;
> 
> > Exposing this information outside of the MD code base (pmap(9)) breaks
> > encapsulation.
> 
> I never intent to "define" or "extend" MI thing.
> 
> > but adding some generic hook in all the AST code does not look like a good
> > exercise in code encapsulation 
> 
> Proposed hook point is at exception return path just before return from
> exception instruction sequence get executed.  It's coded in assembly.
> If specific port wants to do nothing, hook is not necessary.

That's not what your original email said:


I would propose here to add a new hook in exception return
path for every NetBSD ports.  The hook point is at right
after ast() call.  The hook is to call TLB ASID bump op
(to write EntryHi with a single mtc0 instruction for MIPS
architecture , for example).   It should be noted that the
hook is also useful to do "isync operation" for the process
which needs to invalidate instruction cache to continue.


Eduardo