On Thu, 4 Jul 2013, Benjamin Herrenschmidt wrote: > On Thu, 2013-07-04 at 09:31 +0100, David Laight wrote: > > Do you need to execute 'sync' here? > > It is worth checking whether the trap entry/exit doesn't > > do an implicit one for you. > > Not really. It does an implicit isync (more than one even) but not a > sync.
The execution of a sync is required because the original sync variant instruction is not actually executed, and, per Ben, no other explicit sync exists in the exception handler. If the ISA extends the sync instruction using its reserved bits, the intent would also be that executing a heavyweight sync is suitably compatible, otherwise they should have modified some other synchronization instruction. This patch ensures at least one sync instruction is executed for each sync variant instruction executed that triggers a program exception. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev