// SPDX-License-Identifier: GPL-2.0 #include <linux/nmi.h> #include <linux/cpufreq.h> #include <linux/perf/arm_pmu.h> /* * Safe maximum CPU frequency in case a particular platform doesn't implement * cpufreq driver. Although, architecture doesn't put any restrictions on * maximum frequency but 5 GHz seems to be safe maximum given the available * Arm CPUs in the market which are clocked much less than 5 GHz. On the other * hand, we can't make it much higher as it would lead to a large hard-lockup * detection timeout on parts which are running slower (eg. 1GHz on * Developerbox) and doesn't possess a cpufreq driver. */ #define SAFE_MAX_CPU_FREQ 5000000000UL // 5 GHz u64 hw_nmi_get_sample_period(int watchdog_thresh) { unsigned int cpu = smp_processor_id(); unsigned long max_cpu_freq; max_cpu_freq = cpufreq_get_hw_max_freq(cpu) * 1000UL; if (!max_cpu_freq) max_cpu_freq = SAFE_MAX_CPU_FREQ; return (u64)max_cpu_freq * watchdog_thresh; } bool __init arch_perf_nmi_is_available(void) { /* * hardlockup_detector_perf_init() will success even if Pseudo-NMI turns off, * however, the pmu interrupts will act like a normal interrupt instead of * NMI and the hardlockup detector would be broken. */ return arm_pmu_irq_is_nmi(); }