On Mon, Feb 15, 2016 at 07:54:26PM +0100, Rafael J. Wysocki wrote: > On Mon, Feb 15, 2016 at 7:49 PM, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: > > Given that OMAP3 is a UP system, there is zero chance that it has > > registered the magic hook that delivers IPIs (its interrupt controller > > is not even capable of doing so). > > > > I don't really know the context, but IPIs on a UP system seem at best odd. > > That would explain it, thanks. > > So it looks like we should always use irq_work_queue() on UP even if > CONFIG_SMP is set, shouldn't we? irq_work_queue_on() doesn't check whether 'cpu' is the CPU that we're running on. This is a problem where we want to be able to run a kernel built for SMP on a UP system. I guess the question is whether irq_work_queue_on() is buggy, or whether our implementation of arch_send_call_function_single_ipi() is buggy. Should arch_send_call_function_single_ipi() do something on UP systems, if so what? We don't have IPIs on UP systems, so we can't raise any interrupts. So, should we call generic_smp_call_function_interrupt() directly from it? Some clues would be good... -- RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
