Re: CVS commit: src/sys/arch/mips/mips

[Antti Kantee <pooka%netbsd.org@localhost>]

On Mon Nov 08 2010 at 21:40:49 +0000, David Holland wrote:
> On Mon, Nov 08, 2010 at 06:09:39PM +0000, Antti Kantee wrote:
>  > Modified Files:
>  >    src/sys/arch/mips/mips: locore_mips1.S
>  > 
>  > Log Message:
>  > In TLBRead, restore PID before doing the saves so that the caller's
>  > TLB entries are used instead of the PID given as the argument.
>  > 
>  > from Alessandro Forin
> 
> This doesn't make any sense.
> 
> As far as I can tell, the real problem is that the code is not
> attending to pipeline hazards properly; moving things around until it
> experimentally seems to work is just going to create other odd
> behavior sometime down the line under different timing circumstances.
> 
> I don't have a mips1-specific reference on hand, but my recollection
> is that you need *three* nops when messing with cop0 registers for all
> effects to flush through.

locore_mips1.S doesn't agree with your recollection, e.g. mips1_TLBUpdate
right above mips1_TLBRead.