On 03/29/2013 12:53 PM, Nicolas Pitre wrote: > On Fri, 29 Mar 2013, Stefano Stabellini wrote: > >> On Fri, 29 Mar 2013, Nicolas Pitre wrote: >>> On Fri, 29 Mar 2013, Stefano Stabellini wrote: >>> >>>> If PSCI initializes correctly and PSCI SMP operations are available, use >>>> them. >>>> This is required for SMP support in Dom0 on Xen. >>>> >>>> Signed-off-by: Stefano Stabellini <stefano.stabell...@eu.citrix.com> >>>> CC: will.dea...@arm.com >>>> CC: a...@arndb.de >>>> CC: marc.zyng...@arm.com >>>> CC: li...@arm.linux.org.uk >>>> CC: n...@linaro.org >>> >>> I'd suggest you also include in your series the patch I posted earlier >>> providing a runtime mdesc->smp_init method as well. >> >> OK. >> >> >>> This way the >>> priority order would be: >>> >>> - If mdesc->smp_init is non null then use that. >>> >>> - Otherwise, if PSCI is available then use that. >>> >>> - Otherwise use mdesc->smp. >>> >>> This way, if the PSCI default has to be overriden (like in the MCPM case >>> because it needs to wrap PSCI itself, or to cover Rob's concern) then >>> this can be achieved at run time on a per mdesc basis. >> >> Actually that's not a bad idea, it could make everybody happy. >> What about the following, in this precise order: >> >> - if a xen hypervisor node is present on device tree, use PSCI; >> - otherwise if mdesc->smp_init is non null then use it; >> - otherwise if PSCI is available then use it; >> - otherwise use mdesc->smp. >> >> It's the most practical solution to satisfy everybody's needs. > > Maybe I'm missing something obvious, but why can't xen declare a mdesc > of its own? Given it is going to tweak the DT passed to the kernel > anyway that shouldn't be a problem.
Xen does have it's own mdesc. It is (or will be) mach-virt, but that is only for DomU guests. For Dom0, you still need all the platform specific code except smp_ops. However, I'm doubtful this would work without other changes on more complicated platforms like OMAP. I would say wait to add this until you have platforms that actually need the first case. Rob > > That would be more eleguant than adding xen exception hooks in generic > code. > > > Nicolas > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-ker...@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
