Re: [RFC, kernel] powerpc/ioda: Set "read" permission when "write" is set

On 02/15/2016 09:18 PM, Michael Ellerman wrote:

On Tue, 2016-12-01 at 04:40:20 UTC, Alexey Kardashevskiy wrote:

quoted

Quite often drivers set only "write" permission assuming that this
includes "read" permission as well and this works on plenty platforms.
However IODA2 is strict about this and produces an EEH when "read"
permission is not and reading happens.

This adds a workaround in IODA code to always add the "read" bit when
the "write" bit is set.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Alexey Kardashevskiy <redacted>
Tested-by: Douglas Miller <redacted>

Are you planning on sending a non-RFC version of this?

If so is it an urgent fix I should send upstream now? And if so should it
also be CC'ed to stable?

cheers

I vote for the more-urgent case. This is the result of a fairly recent 
change in behavior and we may not have found all the adapters that will 
break yet. If we get this upstream sooner, it means less exposure.