Merge "Perf: arm64: tracectr: initialize counts after hotplug" (d32d6fcf) · Commits · e / devices / android_kernel_sony_msm8994

arch/arm64/kernel/perf_debug.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -32,6 +32,7 @@ static char *descriptions =
		" 7 Perf: arm64: Update PMU force reset\n"
		" 8 Perf: arm64: Use device tree property for CTI PMU workaround\n"
		" 9 Perf: arm64: make request irq pmu-dependent\n"
		"10 Perf: arm64: tracectr: initialize counts after hotplug\n"
		;

		static ssize_t desc_read(struct file fp, char __user buf,

arch/arm64/kernel/perf_trace_counters.c

+55 −4

Original line number	Diff line number	Diff line
		@@ -22,19 +22,68 @@ static unsigned int tp_pid_state;
		DEFINE_PER_CPU(u32, previous_ccnt);
		DEFINE_PER_CPU(u32[NUM_L1_CTRS], previous_l1_cnts);
		DEFINE_PER_CPU(u32, old_pid);
		DEFINE_PER_CPU(u32, hotplug_flag);

		static int tracectr_cpu_hotplug_notifier(struct notifier_block *self,
		unsigned long action, void *hcpu)
		{
		unsigned long cpu = (unsigned long)hcpu;

		if ((action & (~CPU_TASKS_FROZEN)) == CPU_STARTING)
		per_cpu(hotplug_flag, cpu) = 1;

		return NOTIFY_OK;
		}

		static struct notifier_block tracectr_cpu_hotplug_notifier_block = {
		.notifier_call = tracectr_cpu_hotplug_notifier,
		};

		static void setup_prev_cnts(u32 cpu)
		{
		int i;
		u32 cnten_val;

		asm volatile("mrs %0, pmcntenset_el0" : "=r" (cnten_val));
		/* Disable all the counters that were enabled */
		asm volatile("msr pmcntenclr_el0, %0" : : "r" (cnten_val));
		if (cnten_val & CC)
		asm volatile("mrs %0, pmccntr_el0"
		: "=r"(per_cpu(previous_ccnt, cpu)));

		for (i = 0; i < NUM_L1_CTRS; i++) {
		if (cnten_val & (1 << i)) {
		/* Select */
		asm volatile("msr pmselr_el0, %0" : : "r"(i));
		isb();
		/* Read value */
		asm volatile("mrs %0, pmxevcntr_el0"
		: "=r"(per_cpu(previous_l1_cnts[i], cpu)));
		}
		}
		/* Enable all the counters that were disabled */
		asm volatile("msr pmcntenset_el0, %0" : : "r" (cnten_val));
		}

		void tracectr_notifier(void ignore, struct task_struct prev,
		struct task_struct *next)
		{
		int current_pid;
		u32 cpu = next->on_cpu;
		u32 cpu = task_thread_info(next)->cpu;

		if (tp_pid_state != 1)
		return;
		current_pid = next->pid;
		if (per_cpu(old_pid, cpu) != -1)
		if (per_cpu(old_pid, cpu) != -1) {

		if (per_cpu(hotplug_flag, cpu) == 1) {
		per_cpu(hotplug_flag, cpu) = 0;
		setup_prev_cnts(cpu);
		} else {
		trace_sched_switch_with_ctrs(per_cpu(old_pid, cpu),
		current_pid);
		}
		}
		per_cpu(old_pid, cpu) = current_pid;
		}

		@@ -115,11 +164,13 @@ int __init init_tracecounters(void)
		}
		for_each_possible_cpu(cpu)
		per_cpu(old_pid, cpu) = -1;
		register_cpu_notifier(&tracectr_cpu_hotplug_notifier_block);
		return 0;
		}

		int __exit exit_tracecounters(void)
		{
		unregister_cpu_notifier(&tracectr_cpu_hotplug_notifier_block);
		return 0;
		}
		late_initcall(init_tracecounters);