More details on the telnet with CONFIG_PIN_TLB problems

[Matt Porter]

On Tue, Jun 04, 2002 at 10:54:51PM +1000, Paul Mackerras wrote:
>
> Looks like Ben and I have found the problem; Ben added an isync and a
> sync to set_context() after setting the PID register and that seems to
> have fixed it.  It makes sense, as isync invalidates the shadow DTLB
> and ITLB.  (The sync may be unnecessary.)

Makes sense, I was telling some folks at work that it had to be a
40x specific code problem.  The 440 has had an isync in set_context()
and doesn't see this problem (and by default uses pinned TLBs).
Changing the PID is a context changing event that requires a context
synchronization.  The sync shouldn't be necessary per the UM and
seems to be true in practice from my 440 testing.

Regards,
--
Matt Porter
porter at cox.net
This is Linux Country. On a quiet night, you can hear Windows reboot.

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