Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[karo-tx-linux.git] / drivers / oprofile / nmi_timer_int.c

diff --git a/drivers/oprofile/nmi_timer_int.c b/drivers/oprofile/nmi_timer_int.c
new file mode 100644 (file)
index 0000000..76f1c93
--- /dev/null
+++ b/drivers/oprofile/nmi_timer_int.c
@@ -0,0 +1,173 @@
+/**
+ * @file nmi_timer_int.c
+ *
+ * @remark Copyright 2011 Advanced Micro Devices, Inc.
+ *
+ * @author Robert Richter <robert.richter@amd.com>
+ */
+
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/errno.h>
+#include <linux/oprofile.h>
+#include <linux/perf_event.h>
+
+#ifdef CONFIG_OPROFILE_NMI_TIMER
+
+static DEFINE_PER_CPU(struct perf_event *, nmi_timer_events);
+static int ctr_running;
+
+static struct perf_event_attr nmi_timer_attr = {
+       .type           = PERF_TYPE_HARDWARE,
+       .config         = PERF_COUNT_HW_CPU_CYCLES,
+       .size           = sizeof(struct perf_event_attr),
+       .pinned         = 1,
+       .disabled       = 1,
+};
+
+static void nmi_timer_callback(struct perf_event *event,
+                              struct perf_sample_data *data,
+                              struct pt_regs *regs)
+{
+       event->hw.interrupts = 0;       /* don't throttle interrupts */
+       oprofile_add_sample(regs, 0);
+}
+
+static int nmi_timer_start_cpu(int cpu)
+{
+       struct perf_event *event = per_cpu(nmi_timer_events, cpu);
+
+       if (!event) {
+               event = perf_event_create_kernel_counter(&nmi_timer_attr, cpu, NULL,
+                                                        nmi_timer_callback, NULL);
+               if (IS_ERR(event))
+                       return PTR_ERR(event);
+               per_cpu(nmi_timer_events, cpu) = event;
+       }
+
+       if (event && ctr_running)
+               perf_event_enable(event);
+
+       return 0;
+}
+
+static void nmi_timer_stop_cpu(int cpu)
+{
+       struct perf_event *event = per_cpu(nmi_timer_events, cpu);
+
+       if (event && ctr_running)
+               perf_event_disable(event);
+}
+
+static int nmi_timer_cpu_notifier(struct notifier_block *b, unsigned long action,
+                                 void *data)
+{
+       int cpu = (unsigned long)data;
+       switch (action) {
+       case CPU_DOWN_FAILED:
+       case CPU_ONLINE:
+               nmi_timer_start_cpu(cpu);
+               break;
+       case CPU_DOWN_PREPARE:
+               nmi_timer_stop_cpu(cpu);
+               break;
+       }
+       return NOTIFY_DONE;
+}
+
+static struct notifier_block nmi_timer_cpu_nb = {
+       .notifier_call = nmi_timer_cpu_notifier
+};
+
+static int nmi_timer_start(void)
+{
+       int cpu;
+
+       get_online_cpus();
+       ctr_running = 1;
+       for_each_online_cpu(cpu)
+               nmi_timer_start_cpu(cpu);
+       put_online_cpus();
+
+       return 0;
+}
+
+static void nmi_timer_stop(void)
+{
+       int cpu;
+
+       get_online_cpus();
+       for_each_online_cpu(cpu)
+               nmi_timer_stop_cpu(cpu);
+       ctr_running = 0;
+       put_online_cpus();
+}
+
+static void nmi_timer_shutdown(void)
+{
+       struct perf_event *event;
+       int cpu;
+
+       get_online_cpus();
+       unregister_cpu_notifier(&nmi_timer_cpu_nb);
+       for_each_possible_cpu(cpu) {
+               event = per_cpu(nmi_timer_events, cpu);
+               if (!event)
+                       continue;
+               perf_event_disable(event);
+               per_cpu(nmi_timer_events, cpu) = NULL;
+               perf_event_release_kernel(event);
+       }
+
+       put_online_cpus();
+}
+
+static int nmi_timer_setup(void)
+{
+       int cpu, err;
+       u64 period;
+
+       /* clock cycles per tick: */
+       period = (u64)cpu_khz * 1000;
+       do_div(period, HZ);
+       nmi_timer_attr.sample_period = period;
+
+       get_online_cpus();
+       err = register_cpu_notifier(&nmi_timer_cpu_nb);
+       if (err)
+               goto out;
+       /* can't attach events to offline cpus: */
+       for_each_online_cpu(cpu) {
+               err = nmi_timer_start_cpu(cpu);
+               if (err)
+                       break;
+       }
+       if (err)
+               nmi_timer_shutdown();
+out:
+       put_online_cpus();
+       return err;
+}
+
+int __init op_nmi_timer_init(struct oprofile_operations *ops)
+{
+       int err = 0;
+
+       err = nmi_timer_setup();
+       if (err)
+               return err;
+       nmi_timer_shutdown();           /* only check, don't alloc */
+
+       ops->create_files       = NULL;
+       ops->setup              = nmi_timer_setup;
+       ops->shutdown           = nmi_timer_shutdown;
+       ops->start              = nmi_timer_start;
+       ops->stop               = nmi_timer_stop;
+       ops->cpu_type           = "timer";
+
+       printk(KERN_INFO "oprofile: using NMI timer interrupt.\n");
+
+       return 0;
+}
+
+#endif