--- /dev/null
+/*
+ * Copyright 2010 ARM Ltd.
+ * Copyright 2012 Advanced Micro Devices, Inc., Robert Richter
+ *
+ * Perf-events backend for OProfile.
+ */
+#include <linux/perf_event.h>
+#include <linux/platform_device.h>
+#include <linux/oprofile.h>
+#include <linux/slab.h>
+
+/*
+ * Per performance monitor configuration as set via oprofilefs.
+ */
+struct op_counter_config {
+ unsigned long count;
+ unsigned long enabled;
+ unsigned long event;
+ unsigned long unit_mask;
+ unsigned long kernel;
+ unsigned long user;
+ struct perf_event_attr attr;
+};
+
+static int oprofile_perf_enabled;
+static DEFINE_MUTEX(oprofile_perf_mutex);
+
+static struct op_counter_config *counter_config;
+static DEFINE_PER_CPU(struct perf_event **, perf_events);
+static int num_counters;
+
+/*
+ * Overflow callback for oprofile.
+ */
+static void op_overflow_handler(struct perf_event *event,
+ struct perf_sample_data *data, struct pt_regs *regs)
+{
+ int id;
+ u32 cpu = smp_processor_id();
+
+ for (id = 0; id < num_counters; ++id)
+ if (per_cpu(perf_events, cpu)[id] == event)
+ break;
+
+ if (id != num_counters)
+ oprofile_add_sample(regs, id);
+ else
+ pr_warning("oprofile: ignoring spurious overflow "
+ "on cpu %u\n", cpu);
+}
+
+/*
+ * Called by oprofile_perf_setup to create perf attributes to mirror the oprofile
+ * settings in counter_config. Attributes are created as `pinned' events and
+ * so are permanently scheduled on the PMU.
+ */
+static void op_perf_setup(void)
+{
+ int i;
+ u32 size = sizeof(struct perf_event_attr);
+ struct perf_event_attr *attr;
+
+ for (i = 0; i < num_counters; ++i) {
+ attr = &counter_config[i].attr;
+ memset(attr, 0, size);
+ attr->type = PERF_TYPE_RAW;
+ attr->size = size;
+ attr->config = counter_config[i].event;
+ attr->sample_period = counter_config[i].count;
+ attr->pinned = 1;
+ }
+}
+
+static int op_create_counter(int cpu, int event)
+{
+ struct perf_event *pevent;
+
+ if (!counter_config[event].enabled || per_cpu(perf_events, cpu)[event])
+ return 0;
+
+ pevent = perf_event_create_kernel_counter(&counter_config[event].attr,
+ cpu, NULL,
+ op_overflow_handler, NULL);
+
+ if (IS_ERR(pevent))
+ return PTR_ERR(pevent);
+
+ if (pevent->state != PERF_EVENT_STATE_ACTIVE) {
+ perf_event_release_kernel(pevent);
+ pr_warning("oprofile: failed to enable event %d "
+ "on CPU %d\n", event, cpu);
+ return -EBUSY;
+ }
+
+ per_cpu(perf_events, cpu)[event] = pevent;
+
+ return 0;
+}
+
+static void op_destroy_counter(int cpu, int event)
+{
+ struct perf_event *pevent = per_cpu(perf_events, cpu)[event];
+
+ if (pevent) {
+ perf_event_release_kernel(pevent);
+ per_cpu(perf_events, cpu)[event] = NULL;
+ }
+}
+
+/*
+ * Called by oprofile_perf_start to create active perf events based on the
+ * perviously configured attributes.
+ */
+static int op_perf_start(void)
+{
+ int cpu, event, ret = 0;
+
+ for_each_online_cpu(cpu) {
+ for (event = 0; event < num_counters; ++event) {
+ ret = op_create_counter(cpu, event);
+ if (ret)
+ return ret;
+ }
+ }
+
+ return ret;
+}
+
+/*
+ * Called by oprofile_perf_stop at the end of a profiling run.
+ */
+static void op_perf_stop(void)
+{
+ int cpu, event;
+
+ for_each_online_cpu(cpu)
+ for (event = 0; event < num_counters; ++event)
+ op_destroy_counter(cpu, event);
+}
+
+static int oprofile_perf_create_files(struct dentry *root)
+{
+ unsigned int i;
+
+ for (i = 0; i < num_counters; i++) {
+ struct dentry *dir;
+ char buf[4];
+
+ snprintf(buf, sizeof buf, "%d", i);
+ dir = oprofilefs_mkdir(root, buf);
+ oprofilefs_create_ulong(dir, "enabled", &counter_config[i].enabled);
+ oprofilefs_create_ulong(dir, "event", &counter_config[i].event);
+ oprofilefs_create_ulong(dir, "count", &counter_config[i].count);
+ oprofilefs_create_ulong(dir, "unit_mask", &counter_config[i].unit_mask);
+ oprofilefs_create_ulong(dir, "kernel", &counter_config[i].kernel);
+ oprofilefs_create_ulong(dir, "user", &counter_config[i].user);
+ }
+
+ return 0;
+}
+
+static int oprofile_perf_setup(void)
+{
+ raw_spin_lock(&oprofilefs_lock);
+ op_perf_setup();
+ raw_spin_unlock(&oprofilefs_lock);
+ return 0;
+}
+
+static int oprofile_perf_start(void)
+{
+ int ret = -EBUSY;
+
+ mutex_lock(&oprofile_perf_mutex);
+ if (!oprofile_perf_enabled) {
+ ret = 0;
+ op_perf_start();
+ oprofile_perf_enabled = 1;
+ }
+ mutex_unlock(&oprofile_perf_mutex);
+ return ret;
+}
+
+static void oprofile_perf_stop(void)
+{
+ mutex_lock(&oprofile_perf_mutex);
+ if (oprofile_perf_enabled)
+ op_perf_stop();
+ oprofile_perf_enabled = 0;
+ mutex_unlock(&oprofile_perf_mutex);
+}
+
+#ifdef CONFIG_PM
+
+static int oprofile_perf_suspend(struct platform_device *dev, pm_message_t state)
+{
+ mutex_lock(&oprofile_perf_mutex);
+ if (oprofile_perf_enabled)
+ op_perf_stop();
+ mutex_unlock(&oprofile_perf_mutex);
+ return 0;
+}
+
+static int oprofile_perf_resume(struct platform_device *dev)
+{
+ mutex_lock(&oprofile_perf_mutex);
+ if (oprofile_perf_enabled && op_perf_start())
+ oprofile_perf_enabled = 0;
+ mutex_unlock(&oprofile_perf_mutex);
+ return 0;
+}
+
+static struct platform_driver oprofile_driver = {
+ .driver = {
+ .name = "oprofile-perf",
+ },
+ .resume = oprofile_perf_resume,
+ .suspend = oprofile_perf_suspend,
+};
+
+static struct platform_device *oprofile_pdev;
+
+static int __init init_driverfs(void)
+{
+ int ret;
+
+ ret = platform_driver_register(&oprofile_driver);
+ if (ret)
+ return ret;
+
+ oprofile_pdev = platform_device_register_simple(
+ oprofile_driver.driver.name, 0, NULL, 0);
+ if (IS_ERR(oprofile_pdev)) {
+ ret = PTR_ERR(oprofile_pdev);
+ platform_driver_unregister(&oprofile_driver);
+ }
+
+ return ret;
+}
+
+static void exit_driverfs(void)
+{
+ platform_device_unregister(oprofile_pdev);
+ platform_driver_unregister(&oprofile_driver);
+}
+
+#else
+
+static inline int init_driverfs(void) { return 0; }
+static inline void exit_driverfs(void) { }
+
+#endif /* CONFIG_PM */
+
+void oprofile_perf_exit(void)
+{
+ int cpu, id;
+ struct perf_event *event;
+
+ for_each_possible_cpu(cpu) {
+ for (id = 0; id < num_counters; ++id) {
+ event = per_cpu(perf_events, cpu)[id];
+ if (event)
+ perf_event_release_kernel(event);
+ }
+
+ kfree(per_cpu(perf_events, cpu));
+ }
+
+ kfree(counter_config);
+ exit_driverfs();
+}
+
+int __init oprofile_perf_init(struct oprofile_operations *ops)
+{
+ int cpu, ret = 0;
+
+ ret = init_driverfs();
+ if (ret)
+ return ret;
+
+ num_counters = perf_num_counters();
+ if (num_counters <= 0) {
+ pr_info("oprofile: no performance counters\n");
+ ret = -ENODEV;
+ goto out;
+ }
+
+ counter_config = kcalloc(num_counters,
+ sizeof(struct op_counter_config), GFP_KERNEL);
+
+ if (!counter_config) {
+ pr_info("oprofile: failed to allocate %d "
+ "counters\n", num_counters);
+ ret = -ENOMEM;
+ num_counters = 0;
+ goto out;
+ }
+
+ for_each_possible_cpu(cpu) {
+ per_cpu(perf_events, cpu) = kcalloc(num_counters,
+ sizeof(struct perf_event *), GFP_KERNEL);
+ if (!per_cpu(perf_events, cpu)) {
+ pr_info("oprofile: failed to allocate %d perf events "
+ "for cpu %d\n", num_counters, cpu);
+ ret = -ENOMEM;
+ goto out;
+ }
+ }
+
+ ops->create_files = oprofile_perf_create_files;
+ ops->setup = oprofile_perf_setup;
+ ops->start = oprofile_perf_start;
+ ops->stop = oprofile_perf_stop;
+ ops->shutdown = oprofile_perf_stop;
+ ops->cpu_type = op_name_from_perf_id();
+
+ if (!ops->cpu_type)
+ ret = -ENODEV;
+ else
+ pr_info("oprofile: using %s\n", ops->cpu_type);
+
+out:
+ if (ret)
+ oprofile_perf_exit();
+
+ return ret;
+}
Code Review / kvmfornfv.git / blobdiff