SMP in 32-bit arch/powerpc

Adrian Cox adrian at
Thu Aug 17 17:19:04 EST 2006

On Thu, 2006-08-17 at 01:12 +0200, Benjamin Herrenschmidt wrote:
> For completeness, there is a known bug with 32 bits and SMP regarding
> icache coherency.... If you have random SIGILL/SEGV under load, that's
> probably what you are hitting. The problem is due to the way we do the
> coherency and isn't trivial to fix unfortunately, though it's also
> fairly rare.

Could you give a few more details?  I'd not heard of the problem before,
and I couldn't find any references with a few quick searches. I've not
seen the problem myself, but I've not run any heavy page fault loads,
only Altivec load.

Adrian Cox <adrian at>

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