| Message ID | 20220427161340.8518-7-lecopzer.chen@mediatek.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Support hld delayed init based on Pseudo-NMI for arm64 | expand |
On Thu 2022-04-28 00:13:40, Lecopzer Chen wrote: > With the recent feature added to enable perf events to use pseudo NMIs > as interrupts on platforms which support GICv3 or later, its now been > possible to enable hard lockup detector (or NMI watchdog) on arm64 > platforms. So enable corresponding support. > > One thing to note here is that normally lockup detector is initialized > just after the early initcalls but PMU on arm64 comes up much later as > device_initcall(). To cope with that, overriding watchdog_nmi_probe() to > let the watchdog framework know PMU not ready, and inform the framework > to re-initialize lockup detection once PMU has been initialized. > > [1]: http://lore.kernel.org/linux-arm-kernel/1610712101-14929-1-git-send-email-sumit.garg@linaro.org > > --- a/arch/arm64/kernel/perf_event.c > +++ b/arch/arm64/kernel/perf_event.c > @@ -1390,10 +1391,15 @@ static struct platform_driver armv8_pmu_driver = { > > static int __init armv8_pmu_driver_init(void) > { > + int ret; > + > if (acpi_disabled) > - return platform_driver_register(&armv8_pmu_driver); > + ret = platform_driver_register(&armv8_pmu_driver); > else > - return arm_pmu_acpi_probe(armv8_pmuv3_pmu_init); > + ret = arm_pmu_acpi_probe(armv8_pmuv3_pmu_init); > + > + retry_lockup_detector_init(); Does it makes sense to call retry_lockup_detector_init() when the above returned an error? Should it be? if (!ret) retry_lockup_detector_init(); > + return ret; > } > device_initcall(armv8_pmu_driver_init) I am not qualified to ack the arm-specific code. But otherwise the change looks reasonable. Best Regards, Petr
> > to re-initialize lockup detection once PMU has been initialized. > > > > [1]: http://lore.kernel.org/linux-arm-kernel/1610712101-14929-1-git-send-email-sumit.garg@linaro.org > > > > --- a/arch/arm64/kernel/perf_event.c > > +++ b/arch/arm64/kernel/perf_event.c > > @@ -1390,10 +1391,15 @@ static struct platform_driver armv8_pmu_driver = { > > > > static int __init armv8_pmu_driver_init(void) > > { > > + int ret; > > + > > if (acpi_disabled) > > - return platform_driver_register(&armv8_pmu_driver); > > + ret = platform_driver_register(&armv8_pmu_driver); > > else > > - return arm_pmu_acpi_probe(armv8_pmuv3_pmu_init); > > + ret = arm_pmu_acpi_probe(armv8_pmuv3_pmu_init); > > + > > + retry_lockup_detector_init(); > > Does it makes sense to call retry_lockup_detector_init() when > the above returned an error? Should it be? > > if (!ret) > retry_lockup_detector_init(); Oh I think you're right, I'll add a checking here. > > > + return ret; > > } > > device_initcall(armv8_pmu_driver_init) > > > I am not qualified to ack the arm-specific code. But otherwise > the change looks reasonable. Thanks for your help, I'l rebase on 5.19 -rc1 and seek reviewing for ARM relative part. thanks BRs, Lecopzer
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 20ea89d9ac2f..9d48fe4ce041 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -184,12 +184,14 @@ config ARM64 select HAVE_FUNCTION_ERROR_INJECTION select HAVE_FUNCTION_GRAPH_TRACER select HAVE_GCC_PLUGINS + select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI select HAVE_HW_BREAKPOINT if PERF_EVENTS select HAVE_IRQ_TIME_ACCOUNTING select HAVE_KVM select HAVE_NMI select HAVE_PATA_PLATFORM select HAVE_PERF_EVENTS + select HAVE_PERF_EVENTS_NMI if ARM64_PSEUDO_NMI select HAVE_PERF_REGS select HAVE_PERF_USER_STACK_DUMP select HAVE_PREEMPT_DYNAMIC_KEY diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c index cb69ff1e6138..d51ee09592d7 100644 --- a/arch/arm64/kernel/perf_event.c +++ b/arch/arm64/kernel/perf_event.c @@ -23,6 +23,7 @@ #include <linux/platform_device.h> #include <linux/sched_clock.h> #include <linux/smp.h> +#include <linux/nmi.h> /* ARMv8 Cortex-A53 specific event types. */ #define ARMV8_A53_PERFCTR_PREF_LINEFILL 0xC2 @@ -1390,10 +1391,15 @@ static struct platform_driver armv8_pmu_driver = { static int __init armv8_pmu_driver_init(void) { + int ret; + if (acpi_disabled) - return platform_driver_register(&armv8_pmu_driver); + ret = platform_driver_register(&armv8_pmu_driver); else - return arm_pmu_acpi_probe(armv8_pmuv3_pmu_init); + ret = arm_pmu_acpi_probe(armv8_pmuv3_pmu_init); + + retry_lockup_detector_init(); + return ret; } device_initcall(armv8_pmu_driver_init) diff --git a/arch/arm64/kernel/watchdog_hld.c b/arch/arm64/kernel/watchdog_hld.c index de43318e4dd6..c9c6ec889c15 100644 --- a/arch/arm64/kernel/watchdog_hld.c +++ b/arch/arm64/kernel/watchdog_hld.c @@ -1,5 +1,7 @@ // 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 @@ -23,3 +25,15 @@ u64 hw_nmi_get_sample_period(int watchdog_thresh) return (u64)max_cpu_freq * watchdog_thresh; } +int __init watchdog_nmi_probe(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. + */ + if (!arm_pmu_irq_is_nmi()) + return -ENODEV; + + return hardlockup_detector_perf_init(); +} diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c index 59d3980b8ca2..ceee2c55d436 100644 --- a/drivers/perf/arm_pmu.c +++ b/drivers/perf/arm_pmu.c @@ -697,6 +697,11 @@ static int armpmu_get_cpu_irq(struct arm_pmu *pmu, int cpu) return per_cpu(hw_events->irq, cpu); } +bool arm_pmu_irq_is_nmi(void) +{ + return has_nmi; +} + /* * PMU hardware loses all context when a CPU goes offline. * When a CPU is hotplugged back in, since some hardware registers are diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h index 0407a38b470a..29c56c92bab7 100644 --- a/include/linux/perf/arm_pmu.h +++ b/include/linux/perf/arm_pmu.h @@ -171,6 +171,8 @@ void kvm_host_pmu_init(struct arm_pmu *pmu); #define kvm_host_pmu_init(x) do { } while(0) #endif +bool arm_pmu_irq_is_nmi(void); + /* Internal functions only for core arm_pmu code */ struct arm_pmu *armpmu_alloc(void); struct arm_pmu *armpmu_alloc_atomic(void);