On Tue, Nov 27, 2012 at 03:42:39PM -0800, Andrew Morton wrote: > > + /* Do not allow to execute any other task */ > > + spin_lock_irqsave(&lock, flags); > > + while (1); > > I suspect this doesn't do what you want it to do. > > Firstly, please provide adequate code comments here so that code > readers do not also need to be mind readers. > > If you want to stop this CPU dead in its tracks (why?) then > > local_irq_disable(); > while (1) > ; /* Note correct code layout */ > > will do it. But it means that the NMI watchdog (if present) will come > along and whack the machine in the head a few seconds later. And this > does nothing to stop other CPUs. > > But not being a mind reader, I'm really at a loss to suggest what > should be done here. It's hooking into the pm_power_off hook, which is called from kernel/sys.c via arch code. We will have already stopped all other CPUs at this point. Why there's that while (1) there I don't know; when pm_power_off is not hooked, we don't do anything like that - and what will happen in that case is we'll return all the way back to sys_reboot(), which will call do_exit(0) on us. I don't see a problem with that, and I don't see why we need to spin (without any power saving too) waiting for some event. If we've called sys_reboot with LINUX_REBOOT_CMD_POWER_OFF, we'd better have already killed most of userspace off by that time anyway. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
