| Message ID | 20210915035103.15586-6-kernelfans@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | watchdog_hld cleanup and async model for arm64 | expand |
On Wed, Sep 15, 2021 at 11:51:03AM +0800, Pingfan Liu wrote: + Petr Mladek > With watchdog_hld armed with the async model, arm64 can probe and enable > perf NMI after smp_init(). At the boot stage, all of cpus arm hard > lockup detector in the async model. > > In this patch, the function hw_nmi_get_sample_period() is borrowed from > [1], credit goes to Sumit. > > [1]: http://lore.kernel.org/linux-arm-kernel/1610712101-14929-1-git-send-email-sumit.garg@linaro.org > > Signed-off-by: Pingfan Liu <kernelfans@gmail.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Arnaldo Carvalho de Melo <acme@kernel.org> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> > Cc: Jiri Olsa <jolsa@redhat.com> > Cc: Namhyung Kim <namhyung@kernel.org> > Cc: Marc Zyngier <maz@kernel.org> > Cc: Julien Thierry <jthierry@redhat.com> > Cc: Kees Cook <keescook@chromium.org> > Cc: Masahiro Yamada <masahiroy@kernel.org> > Cc: Sami Tolvanen <samitolvanen@google.com> > To: linux-arm-kernel@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > --- > arch/arm64/Kconfig | 3 ++ > arch/arm64/include/asm/perf_event.h | 5 ++ > arch/arm64/kernel/Makefile | 1 + > arch/arm64/kernel/perf_event.c | 14 ++++- > arch/arm64/kernel/watchdog_hld.c | 83 +++++++++++++++++++++++++++++ > drivers/perf/arm_pmu.c | 5 ++ > 6 files changed, 109 insertions(+), 2 deletions(-) > create mode 100644 arch/arm64/kernel/watchdog_hld.c > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 62c3c1d2190f..0f49e58a9dd8 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -193,6 +193,9 @@ config ARM64 > select HAVE_PERF_EVENTS > select HAVE_PERF_REGS > select HAVE_PERF_USER_STACK_DUMP > + select HAVE_PERF_EVENTS_NMI > + select HAVE_HARDLOCKUP_DETECTOR_PERF \ > + if PERF_EVENTS && HW_PERF_EVENTS && HAVE_PERF_EVENTS_NMI > select HAVE_REGS_AND_STACK_ACCESS_API > select HAVE_FUNCTION_ARG_ACCESS_API > select HAVE_FUTEX_CMPXCHG if FUTEX > diff --git a/arch/arm64/include/asm/perf_event.h b/arch/arm64/include/asm/perf_event.h > index 4ef6f19331f9..712a75f432f0 100644 > --- a/arch/arm64/include/asm/perf_event.h > +++ b/arch/arm64/include/asm/perf_event.h > @@ -6,6 +6,7 @@ > #ifndef __ASM_PERF_EVENT_H > #define __ASM_PERF_EVENT_H > > +#include <linux/wait.h> > #include <asm/stack_pointer.h> > #include <asm/ptrace.h> > > @@ -259,4 +260,8 @@ extern unsigned long perf_misc_flags(struct pt_regs *regs); > (regs)->pstate = PSR_MODE_EL1h; \ > } > > +extern bool arm_pmu_initialized; > +extern wait_queue_head_t arm_pmu_wait; > +extern bool check_pmu_nmi_ability(void); > + > #endif > diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile > index 3f1490bfb938..789c2fe5bb90 100644 > --- a/arch/arm64/kernel/Makefile > +++ b/arch/arm64/kernel/Makefile > @@ -46,6 +46,7 @@ obj-$(CONFIG_MODULES) += module.o > obj-$(CONFIG_ARM64_MODULE_PLTS) += module-plts.o > obj-$(CONFIG_PERF_EVENTS) += perf_regs.o perf_callchain.o > obj-$(CONFIG_HW_PERF_EVENTS) += perf_event.o > +obj-$(CONFIG_HARDLOCKUP_DETECTOR_PERF) += watchdog_hld.o > obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o > obj-$(CONFIG_CPU_PM) += sleep.o suspend.o > obj-$(CONFIG_CPU_IDLE) += cpuidle.o > diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c > index d07788dad388..c4144cea0d55 100644 > --- a/arch/arm64/kernel/perf_event.c > +++ b/arch/arm64/kernel/perf_event.c > @@ -24,6 +24,9 @@ > #include <linux/sched_clock.h> > #include <linux/smp.h> > > +bool arm_pmu_initialized; > +DECLARE_WAIT_QUEUE_HEAD(arm_pmu_wait); > + > /* ARMv8 Cortex-A53 specific event types. */ > #define ARMV8_A53_PERFCTR_PREF_LINEFILL 0xC2 > > @@ -1284,10 +1287,17 @@ 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_init); > + ret = arm_pmu_acpi_probe(armv8_pmuv3_init); > + > + arm_pmu_initialized = true; > + wake_up_all(&arm_pmu_wait); > + > + return ret; > } > device_initcall(armv8_pmu_driver_init) > > diff --git a/arch/arm64/kernel/watchdog_hld.c b/arch/arm64/kernel/watchdog_hld.c > new file mode 100644 > index 000000000000..18bfa62f1058 > --- /dev/null > +++ b/arch/arm64/kernel/watchdog_hld.c > @@ -0,0 +1,83 @@ > +// SPDX-License-Identifier: GPL-2.0 > +#include <linux/kthread.h> > +#include <linux/sched.h> > +#include <linux/nmi.h> > +#include <linux/cpufreq.h> > +#include <asm/perf_event.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; > +} > + > +static watchdog_nmi_status_reporter status_reporter; > + > +static int hld_enabled_thread_fun(void *unused) > +{ > + struct watchdog_nmi_status status; > + watchdog_nmi_status_reporter local_reporter; > + int ret; > + > + wait_event(arm_pmu_wait, arm_pmu_initialized); > + status.cpu = raw_smp_processor_id(); > + > + if (!check_pmu_nmi_ability()) { > + status.status = -ENODEV; > + goto report; > + } > + > + ret = hardlockup_detector_perf_enable(); > + status.status = ret; > + > +report: > + local_reporter = (watchdog_nmi_status_reporter)atomic64_fetch_and(0, > + (atomic64_t *)&status_reporter); > + if (local_reporter) > + (*local_reporter)(&status); > + > + return 0; > +} > + > +/* As for watchdog_nmi_disable(), using the default implement */ > +void watchdog_nmi_enable(unsigned int cpu) > +{ > + struct task_struct *t; > + > + /* PMU is not ready */ > + if (!arm_pmu_initialized) { > + t = kthread_create_on_cpu(hld_enabled_thread_fun, NULL, cpu, > + "arm64_hld.%u"); > + if (IS_ERR(t)) > + return; > + wake_up_process(t); > + return; > + } > + > + /* For hotplug in cpu */ > + hardlockup_detector_perf_enable(); > +} > + > +int __init watchdog_nmi_probe(watchdog_nmi_status_reporter notifier) > +{ > + /* On arm64, arm pmu is not ready at this stage */ > + status_reporter = notifier; > + return -EBUSY; > +} > + > diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c > index 3cbc3baf087f..e08961b37922 100644 > --- a/drivers/perf/arm_pmu.c > +++ b/drivers/perf/arm_pmu.c > @@ -105,6 +105,11 @@ static DEFINE_PER_CPU(const struct pmu_irq_ops *, cpu_irq_ops); > > static bool has_nmi; > > +bool check_pmu_nmi_ability(void) > +{ > + return has_nmi; > +} > + > static inline u64 arm_pmu_event_max_period(struct perf_event *event) > { > if (event->hw.flags & ARMPMU_EVT_64BIT) > -- > 2.31.1 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 62c3c1d2190f..0f49e58a9dd8 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -193,6 +193,9 @@ config ARM64 select HAVE_PERF_EVENTS select HAVE_PERF_REGS select HAVE_PERF_USER_STACK_DUMP + select HAVE_PERF_EVENTS_NMI + select HAVE_HARDLOCKUP_DETECTOR_PERF \ + if PERF_EVENTS && HW_PERF_EVENTS && HAVE_PERF_EVENTS_NMI select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_FUNCTION_ARG_ACCESS_API select HAVE_FUTEX_CMPXCHG if FUTEX diff --git a/arch/arm64/include/asm/perf_event.h b/arch/arm64/include/asm/perf_event.h index 4ef6f19331f9..712a75f432f0 100644 --- a/arch/arm64/include/asm/perf_event.h +++ b/arch/arm64/include/asm/perf_event.h @@ -6,6 +6,7 @@ #ifndef __ASM_PERF_EVENT_H #define __ASM_PERF_EVENT_H +#include <linux/wait.h> #include <asm/stack_pointer.h> #include <asm/ptrace.h> @@ -259,4 +260,8 @@ extern unsigned long perf_misc_flags(struct pt_regs *regs); (regs)->pstate = PSR_MODE_EL1h; \ } +extern bool arm_pmu_initialized; +extern wait_queue_head_t arm_pmu_wait; +extern bool check_pmu_nmi_ability(void); + #endif diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 3f1490bfb938..789c2fe5bb90 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -46,6 +46,7 @@ obj-$(CONFIG_MODULES) += module.o obj-$(CONFIG_ARM64_MODULE_PLTS) += module-plts.o obj-$(CONFIG_PERF_EVENTS) += perf_regs.o perf_callchain.o obj-$(CONFIG_HW_PERF_EVENTS) += perf_event.o +obj-$(CONFIG_HARDLOCKUP_DETECTOR_PERF) += watchdog_hld.o obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o obj-$(CONFIG_CPU_PM) += sleep.o suspend.o obj-$(CONFIG_CPU_IDLE) += cpuidle.o diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c index d07788dad388..c4144cea0d55 100644 --- a/arch/arm64/kernel/perf_event.c +++ b/arch/arm64/kernel/perf_event.c @@ -24,6 +24,9 @@ #include <linux/sched_clock.h> #include <linux/smp.h> +bool arm_pmu_initialized; +DECLARE_WAIT_QUEUE_HEAD(arm_pmu_wait); + /* ARMv8 Cortex-A53 specific event types. */ #define ARMV8_A53_PERFCTR_PREF_LINEFILL 0xC2 @@ -1284,10 +1287,17 @@ 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_init); + ret = arm_pmu_acpi_probe(armv8_pmuv3_init); + + arm_pmu_initialized = true; + wake_up_all(&arm_pmu_wait); + + return ret; } device_initcall(armv8_pmu_driver_init) diff --git a/arch/arm64/kernel/watchdog_hld.c b/arch/arm64/kernel/watchdog_hld.c new file mode 100644 index 000000000000..18bfa62f1058 --- /dev/null +++ b/arch/arm64/kernel/watchdog_hld.c @@ -0,0 +1,83 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/kthread.h> +#include <linux/sched.h> +#include <linux/nmi.h> +#include <linux/cpufreq.h> +#include <asm/perf_event.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; +} + +static watchdog_nmi_status_reporter status_reporter; + +static int hld_enabled_thread_fun(void *unused) +{ + struct watchdog_nmi_status status; + watchdog_nmi_status_reporter local_reporter; + int ret; + + wait_event(arm_pmu_wait, arm_pmu_initialized); + status.cpu = raw_smp_processor_id(); + + if (!check_pmu_nmi_ability()) { + status.status = -ENODEV; + goto report; + } + + ret = hardlockup_detector_perf_enable(); + status.status = ret; + +report: + local_reporter = (watchdog_nmi_status_reporter)atomic64_fetch_and(0, + (atomic64_t *)&status_reporter); + if (local_reporter) + (*local_reporter)(&status); + + return 0; +} + +/* As for watchdog_nmi_disable(), using the default implement */ +void watchdog_nmi_enable(unsigned int cpu) +{ + struct task_struct *t; + + /* PMU is not ready */ + if (!arm_pmu_initialized) { + t = kthread_create_on_cpu(hld_enabled_thread_fun, NULL, cpu, + "arm64_hld.%u"); + if (IS_ERR(t)) + return; + wake_up_process(t); + return; + } + + /* For hotplug in cpu */ + hardlockup_detector_perf_enable(); +} + +int __init watchdog_nmi_probe(watchdog_nmi_status_reporter notifier) +{ + /* On arm64, arm pmu is not ready at this stage */ + status_reporter = notifier; + return -EBUSY; +} + diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c index 3cbc3baf087f..e08961b37922 100644 --- a/drivers/perf/arm_pmu.c +++ b/drivers/perf/arm_pmu.c @@ -105,6 +105,11 @@ static DEFINE_PER_CPU(const struct pmu_irq_ops *, cpu_irq_ops); static bool has_nmi; +bool check_pmu_nmi_ability(void) +{ + return has_nmi; +} + static inline u64 arm_pmu_event_max_period(struct perf_event *event) { if (event->hw.flags & ARMPMU_EVT_64BIT)
With watchdog_hld armed with the async model, arm64 can probe and enable perf NMI after smp_init(). At the boot stage, all of cpus arm hard lockup detector in the async model. In this patch, the function hw_nmi_get_sample_period() is borrowed from [1], credit goes to Sumit. [1]: http://lore.kernel.org/linux-arm-kernel/1610712101-14929-1-git-send-email-sumit.garg@linaro.org Signed-off-by: Pingfan Liu <kernelfans@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Julien Thierry <jthierry@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Sami Tolvanen <samitolvanen@google.com> To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org --- arch/arm64/Kconfig | 3 ++ arch/arm64/include/asm/perf_event.h | 5 ++ arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/perf_event.c | 14 ++++- arch/arm64/kernel/watchdog_hld.c | 83 +++++++++++++++++++++++++++++ drivers/perf/arm_pmu.c | 5 ++ 6 files changed, 109 insertions(+), 2 deletions(-) create mode 100644 arch/arm64/kernel/watchdog_hld.c