Messages in this thread Patch in this message | | | Date | Thu, 6 Oct 2022 14:37:55 +0100 | Subject | Re: [PATCH V3 4/7] driver/perf/arm_pmu_platform: Add support for BRBE attributes detection | From | James Clark <> |
| |
On 29/09/2022 08:58, Anshuman Khandual wrote: > This adds arm pmu infrastrure to probe BRBE implementation's attributes via > driver exported callbacks later. The actual BRBE feature detection will be > added by the driver itself. > > CPU specific BRBE entries, cycle count, format support gets detected during > PMU init. This information gets saved in per-cpu struct pmu_hw_events which > later helps in operating BRBE during a perf event context. > > Cc: Will Deacon <will@kernel.org> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> > --- > drivers/perf/arm_pmu_platform.c | 34 +++++++++++++++++++++++++++++++++ > 1 file changed, 34 insertions(+) > > diff --git a/drivers/perf/arm_pmu_platform.c b/drivers/perf/arm_pmu_platform.c > index 933b96e243b8..acdc445081aa 100644 > --- a/drivers/perf/arm_pmu_platform.c > +++ b/drivers/perf/arm_pmu_platform.c > @@ -172,6 +172,36 @@ static int armpmu_request_irqs(struct arm_pmu *armpmu) > return err; > } > > +static void arm_brbe_probe_cpu(void *info) > +{ > + struct pmu_hw_events *hw_events; > + struct arm_pmu *armpmu = info; > + > + /* > + * Return from here, if BRBE driver has not been > + * implemented for this PMU. This helps prevent > + * kernel crash later when brbe_probe() will be > + * called on the PMU. > + */ > + if (!armpmu->brbe_probe) > + return; > + > + hw_events = per_cpu_ptr(armpmu->hw_events, smp_processor_id()); > + armpmu->brbe_probe(hw_events); > +} > + > +static int armpmu_request_brbe(struct arm_pmu *armpmu) > +{ > + int cpu, err = 0; > + > + for_each_cpu(cpu, &armpmu->supported_cpus) { > + err = smp_call_function_single(cpu, arm_brbe_probe_cpu, armpmu, 1);
Hi Anshuman,
I have LOCKDEP on and the patchset applied to perf/core (82aad7ff7) on git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git and I get this:
armv8-pmu pmu: hw perfevents: no interrupt-affinity property, guessing. brbe: implementation found on cpu 0
============================= [ BUG: Invalid wait context ] 6.0.0-rc7 #38 Not tainted ----------------------------- kworker/u8:0/9 is trying to lock: ffff000800855898 (&port_lock_key){....}-{3:3}, at: pl011_console_write+0x148/0x240 other info that might help us debug this: context-{2:2} 5 locks held by kworker/u8:0/9: #0: ffff00080032a138 ((wq_completion)eval_map_wq){+.+.}-{0:0}, at: process_one_work+0x200/0x6b0 #1: ffff80000807bde0 ((work_completion)(&eval_map_work)){+.+.}-{0:0}, at: process_one_work+0x200/0x6b0 #2: ffff80000aa3db70 (trace_event_sem){+.+.}-{4:4}, at: trace_event_eval_update+0x28/0x420 #3: ffff80000a9afe58 (console_lock){+.+.}-{0:0}, at: vprintk_emit+0x130/0x380 #4: ffff80000a9aff78 (console_owner){-...}-{0:0}, at: console_emit_next_record.constprop.0+0x128/0x338 stack backtrace: CPU: 0 PID: 9 Comm: kworker/u8:0 Not tainted 6.0.0-rc7 #38 Hardware name: Foundation-v8A (DT) Workqueue: eval_map_wq eval_map_work_func Call trace: dump_backtrace+0x114/0x120 show_stack+0x20/0x58 dump_stack_lvl+0x9c/0xd8 dump_stack+0x18/0x34 __lock_acquire+0x17cc/0x1920 lock_acquire+0x138/0x3b8 _raw_spin_lock+0x58/0x70 pl011_console_write+0x148/0x240 console_emit_next_record.constprop.0+0x194/0x338 console_unlock+0x18c/0x208 vprintk_emit+0x24c/0x380 vprintk_default+0x40/0x50 vprintk+0xd4/0xf0 _printk+0x68/0x90 arm64_pmu_brbe_probe+0x10c/0x128 armv8pmu_brbe_probe+0x18/0x28 arm_brbe_probe_cpu+0x44/0x58 __flush_smp_call_function_queue+0x1d0/0x440 generic_smp_call_function_single_interrupt+0x20/0x78 ipi_handler+0x98/0x368 handle_percpu_devid_irq+0xc0/0x3a8 generic_handle_domain_irq+0x34/0x50 gic_handle_irq+0x58/0x138 call_on_irq_stack+0x2c/0x58 do_interrupt_handler+0x88/0x90 el1_interrupt+0x40/0x78 el1h_64_irq_handler+0x18/0x28 el1h_64_irq+0x64/0x68 trace_event_eval_update+0x114/0x420 eval_map_work_func+0x30/0x40 process_one_work+0x298/0x6b0 worker_thread+0x54/0x408 kthread+0x118/0x128 ret_from_fork+0x10/0x20 brbe: implementation found on cpu 1 brbe: implementation found on cpu 2 brbe: implementation found on cpu 3
> + if (err) > + return err; > + } > + return err; > +} > + > static void armpmu_free_irqs(struct arm_pmu *armpmu) > { > int cpu; > @@ -229,6 +259,10 @@ int arm_pmu_device_probe(struct platform_device *pdev, > if (ret) > goto out_free_irqs; > > + ret = armpmu_request_brbe(pmu); > + if (ret) > + goto out_free_irqs; > + > ret = armpmu_register(pmu); > if (ret) { > dev_err(dev, "failed to register PMU devices!\n");
| |