powerpc/kernel/watchdog.c

1 // SPDX-License-Identifier: GPL-2.0
37  * period, and updates a per-cpu timestamp and a "pending" cpumask. This is
41  * The local soft-NMI, and the SMP checker.
43  * The soft-NMI checker can detect lockups on the local CPU. When interrupts
44  * are disabled with local_irq_disable(), platforms that use soft-masking
50  * The soft-NMI checker will compare the heartbeat timestamp for this CPU
52  * watchdog threshold.
54  * The limitation of the soft-NMI watchdog is that it does not work when
66  * not been updated for a period exceeding the watchdog threshold, then it
131 	hard_irq_disable(); /* Make it soft-NMI safe */  in wd_smp_lock()
154 		 tb_to_ns(tb - per_cpu(wd_timer_tb, cpu)) / 1000000);  in wd_lockup_ipi()
166 	 * If that NMI was taken in some code that is hard-locked, then irqs  in wd_lockup_ipi()
172 	 * the console drivers for us.  in wd_lockup_ipi()
211 	if ((s64)(tb - last_reset) < (s64)wd_smp_panic_timeout_tb)  in watchdog_smp_panic()
236 		 cpu, tb, last_reset, tb_to_ns(tb - last_reset) / 1000000);  in watchdog_smp_panic()
301 	 * wd_smp_lock. All of them are atomic except the case where the  in wd_smp_clear_cpu_pending()
305 	 * hard lockup on our CPU and takes us out of the pending mask. So in  in wd_smp_clear_cpu_pending()
308 	 * In the lockup case, this atomic clear-bit vs a store that refills  in wd_smp_clear_cpu_pending()
310 	 * is atomic so it will not cause the store to get lost, and the store  in wd_smp_clear_cpu_pending()
354 	if ((s64)(tb - wd_smp_last_reset_tb) >= (s64)wd_smp_panic_timeout_tb)  in watchdog_timer_interrupt()
384 	if (tb - per_cpu(wd_timer_tb, cpu) >= wd_panic_timeout_tb) {  in DEFINE_INTERRUPT_HANDLER_NMI()
386 		 * Taking wd_smp_lock here means it is a soft-NMI lock, which  in DEFINE_INTERRUPT_HANDLER_NMI()
407 		pr_emerg("CPU %d self-detected hard LOCKUP @ %pS\n",  in DEFINE_INTERRUPT_HANDLER_NMI()
408 			 cpu, (void *)regs->nip);  in DEFINE_INTERRUPT_HANDLER_NMI()
411 			 tb_to_ns(tb - per_cpu(wd_timer_tb, cpu)) / 1000000);  in DEFINE_INTERRUPT_HANDLER_NMI()
464 	if (tb - per_cpu(wd_timer_tb, cpu) >= ticks) {  in arch_touch_nmi_watchdog()
499 	hrtimer->function = watchdog_timer_fn;  in start_watchdog()
534 	u64 threshold = watchdog_thresh;  in watchdog_calc_timeouts()  local
537 	threshold += (READ_ONCE(wd_timeout_pct) * threshold) / 100;  in watchdog_calc_timeouts()
540 	wd_panic_timeout_tb = threshold * ppc_tb_freq;  in watchdog_calc_timeouts()