parisc: Mark cr16 clocksource unstable on SMP systems (41744213) · Commits · 戴 / test

The cr16 interval timer of each CPU is not syncronized to other cr16 timers in other CPUs in a SMP system. So, delay the registration of the cr16 clocksource until all CPUs have been detected and then - if we are on a SMP machine - mark the cr16 clocksource as unstable and lower it's rating before registering it at the clocksource framework. This patch fixes the stalled CPU warnings which we have seen since introduction of the cr16 clocksource. Signed-off-by:

Helge Deller <deller@gmx.de> Cc: <stable@vger.kernel.org> # v4.8+

arch/parisc/kernel/time.c

+20 −3

Original line number	Diff line number	Diff line
		@@ -235,9 +235,26 @@ void __init time_init(void)

		cr16_hz = 100 * PAGE0->mem_10msec; /* Hz */

		/* register at clocksource framework */
		clocksource_register_hz(&clocksource_cr16, cr16_hz);

		/* register as sched_clock source */
		sched_clock_register(read_cr16_sched_clock, BITS_PER_LONG, cr16_hz);
		}

		static int __init init_cr16_clocksource(void)
		{
		/*
		* The cr16 interval timers are not syncronized across CPUs, so mark
		* them unstable and lower rating on SMP systems.
		*/
		if (num_online_cpus() > 1) {
		clocksource_cr16.flags = CLOCK_SOURCE_UNSTABLE;
		clocksource_cr16.rating = 0;
		}

		/* register at clocksource framework */
		clocksource_register_hz(&clocksource_cr16,
		100 * PAGE0->mem_10msec);

		return 0;
		}

		device_initcall(init_cr16_clocksource);

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