On 21.05.2011, at 11:40, Andreas Färber wrote: > Am 20.05.2011 um 09:40 schrieb Alexander Graf: > >> On 20.05.2011, at 05:34, David Gibson wrote: >> >>> Early ppc64 CPUs include a hack to partially simulate the ppc32 segment >>> registers, by translating writes to them into writes to the SLB. This is >>> not used by any current Linux kernel, but it is used by the openbios used >>> in the qemu mac99 model. >>> >>> Commit 81762d6dd0d430d87024f2c83e9c4dcc4329fb7d, cleaning up the SLB >>> handling introduced a bug in this code, breaking the openbios currently in >>> qemu. Specifically, there was an off by one error bitshuffling the >>> register format used by mtsr into the format needed for the SLB load, >>> causing the flag bits to end up in the wrong place. This caused the >>> storage keys to be wrong under openbios, meaning that the translation code >>> incorrectly thought a legitimate access was a permission violation. >>> >>> This patch fixes the bug, at the same time it fixes some build bug in the >>> MMU debugging code (only exposed when DEBUG_MMU is enabled). >> >> Thanks, applied to ppc-next :) > > Hm. Don't you think we should split off the unrelated debug code fix for > bisecting?
Not sure if it's worth the effort. If you were bisecting before that, you probably had DEBUG_MMU disabled anyways, because you'd otherwise get build breakages before that specific commit anyways, so the commit behaves as if it's only the SLB fix. Alex