Re: tlbia and PPC603

Hi Ben,
Thank you for your reply.

On Wed, Jun 19, 2002 at 05:51:37AM +0200,
Benjamin Herrenschmidt [off-list ref] wrote:

quoted

Try without the ethernet card and switch IDE DMA off and tell me if it is
stable, there could be some cache coherency issues with some of the

chipsets

quoted

used on these machines.

I was able to use both IDE DMA and ethernet card on
linux-2.4.13-pre3-ben0 without problems.

Do you still have this kernel source ? My local repository got
corrupted at some point so I can't go that far in the history.

I would appreciate if you could send me a tarball with at least
the content of arch/ppc/kernel, arch/ppc/mm and include/asm-ppc
so I can do some comparisons.

Anyway I tried rsync kernel without CONFIG_BLK_DEV_IDEDMA_PMAC_AUTO
and compiled tulip as modules (and not loaded), but it still dropped
to xmon randomly.

Ok.

quoted

Another thing you can try is in set_context(), add an isync on the line
that contain the label "3:" as the doc states a context synchronizing
instruction should also be used for data sync. before mtsrin.

I changed set_context() and  it might improve stableness somewhat, but
still dropped to xmon at some occasion.

Hrm...

quoted

Hrm... just in case, try also changing the definition of tlbia macro
in ppc_asm.h to put isync's inside the loop, both before and after the
tlbie's (add too much is no problem for such a test) and tell me if it
has any effect.

With this change combined with set_context() change, crashes
disappeared during boot time (tested 10 times and all trial
succeeded).  It is really improvement.  But still sometimes (5 times
per 10) dropped to xmon while sshd is working by ssh connection from
other machine.

Can you send me a couple of xmon backtraces with lookup in System.map ?

Also, please try editing arch/ppc/kernel/ppc_asm.h and change the definition
of SYNC, SYNC_601 and ISYNC_601 so they unconditionally do the various sync &
isync's (that is remove the BEGIN_FTR_SECTION and END_FTR_SECTION(...) lines
from them.

Ben.


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