From d7a0fe9ef6d6484fca4ba55c19091932337d4272 Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Fri, 19 May 2023 10:18:42 -0700 Subject: [PATCH] arm64: enable perf events based hard lockup detector 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, override arch_perf_nmi_is_available() to let the watchdog framework know PMU not ready, and inform the framework to re-initialize lockup detection once PMU has been initialized. [dianders@chromium.org: only HAVE_HARDLOCKUP_DETECTOR_PERF if the PMU config is enabled] Link: https://lkml.kernel.org/r/20230523073952.1.I60217a63acc35621e13f10be16c0cd7c363caf8c@changeid Link: https://lkml.kernel.org/r/20230519101840.v5.18.Ia44852044cdcb074f387e80df6b45e892965d4a1@changeid Co-developed-by: Sumit Garg Signed-off-by: Sumit Garg Co-developed-by: Pingfan Liu Signed-off-by: Pingfan Liu Signed-off-by: Lecopzer Chen Signed-off-by: Douglas Anderson Cc: Andi Kleen Cc: Catalin Marinas Cc: Chen-Yu Tsai Cc: Christophe Leroy Cc: Colin Cross Cc: Daniel Thompson Cc: "David S. Miller" Cc: Guenter Roeck Cc: Ian Rogers Cc: Marc Zyngier Cc: Mark Rutland Cc: Masayoshi Mizuma Cc: Matthias Kaehlcke Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Petr Mladek Cc: Randy Dunlap Cc: "Ravi V. Shankar" Cc: Ricardo Neri Cc: Stephane Eranian Cc: Stephen Boyd Cc: Tzung-Bi Shih Cc: Will Deacon Signed-off-by: Andrew Morton --- arch/arm64/Kconfig | 3 +++ arch/arm64/kernel/watchdog_hld.c | 12 ++++++++++++ drivers/perf/arm_pmu.c | 5 +++++ drivers/perf/arm_pmuv3.c | 12 ++++++++++-- include/linux/perf/arm_pmu.h | 2 ++ 5 files changed, 32 insertions(+), 2 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index b1201d2..ef87761 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -203,12 +203,15 @@ config ARM64 select HAVE_FUNCTION_ERROR_INJECTION select HAVE_FUNCTION_GRAPH_TRACER select HAVE_GCC_PLUGINS + select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && \ + HW_PERF_EVENTS && HAVE_PERF_EVENTS_NMI select HAVE_HW_BREAKPOINT if PERF_EVENTS select HAVE_IOREMAP_PROT select HAVE_IRQ_TIME_ACCOUNTING select HAVE_KVM select HAVE_NMI 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/watchdog_hld.c b/arch/arm64/kernel/watchdog_hld.c index 2401eb1..dcd2532 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 #include +#include /* * Safe maximum CPU frequency in case a particular platform doesn't implement @@ -22,3 +24,13 @@ u64 hw_nmi_get_sample_period(int watchdog_thresh) 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(); +} diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c index 15bd1e3..7b9caa5 100644 --- a/drivers/perf/arm_pmu.c +++ b/drivers/perf/arm_pmu.c @@ -687,6 +687,11 @@ 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/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c index c98e403..7b28d65 100644 --- a/drivers/perf/arm_pmuv3.c +++ b/drivers/perf/arm_pmuv3.c @@ -22,6 +22,7 @@ #include #include #include +#include #include @@ -1348,10 +1349,17 @@ 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); + + if (!ret) + lockup_detector_retry_init(); + + return ret; } device_initcall(armv8_pmu_driver_init) diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h index 525b5d6..5b00f5c 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); void armpmu_free(struct arm_pmu *pmu); -- 2.7.4