1 files changed, 323 insertions, 0 deletions

diff --git a/drivers/oprofile/oprofile_perf.c b/drivers/oprofile/oprofile_perf.c
new file mode 100644
index 000000000000..b17235a24a4d
--- /dev/null
+++ b/drivers/oprofile/oprofile_perf.c
@@ -0,0 +1,323 @@
+/*
+ * Copyright 2010 ARM Ltd.
+ *
+ * Perf-events backend for OProfile.
+ */
+#include <linux/perf_event.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 struct perf_event **perf_events[nr_cpumask_bits];
+static int num_counters;
+
+/*
+ * Overflow callback for oprofile.
+ */
+static void op_overflow_handler(struct perf_event *event, int unused,
+                        struct perf_sample_data *data, struct pt_regs *regs)
+{
+        int id;
+        u32 cpu = smp_processor_id();
+
+        for (id = 0; id < num_counters; ++id)
+                if (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 || perf_events[cpu][event])
+                return 0;
+
+        pevent = perf_event_create_kernel_counter(&counter_config[event].attr,
+                                                  cpu, -1,
+                                                  op_overflow_handler);
+
+        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;
+        }
+
+        perf_events[cpu][event] = pevent;
+
+        return 0;
+}
+
+static void op_destroy_counter(int cpu, int event)
+{
+        struct perf_event *pevent = perf_events[cpu][event];
+
+        if (pevent) {
+                perf_event_release_kernel(pevent);
+                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 super_block *sb, 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(sb, root, buf);
+                oprofilefs_create_ulong(sb, dir, "enabled", &counter_config[i].enabled);
+                oprofilefs_create_ulong(sb, dir, "event", &counter_config[i].event);
+                oprofilefs_create_ulong(sb, dir, "count", &counter_config[i].count);
+                oprofilefs_create_ulong(sb, dir, "unit_mask", &counter_config[i].unit_mask);
+                oprofilefs_create_ulong(sb, dir, "kernel", &counter_config[i].kernel);
+                oprofilefs_create_ulong(sb, dir, "user", &counter_config[i].user);
+        }
+
+        return 0;
+}
+
+static int oprofile_perf_setup(void)
+{
+        spin_lock(&oprofilefs_lock);
+        op_perf_setup();
+        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 exit_driverfs(void)
+{
+        platform_device_unregister(oprofile_pdev);
+        platform_driver_unregister(&oprofile_driver);
+}
+#else
+static int __init init_driverfs(void) { return 0; }
+#define exit_driverfs() do { } while (0)
+#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 = perf_events[cpu][id];
+                        if (event)
+                                perf_event_release_kernel(event);
+                }
+
+                kfree(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;
+
+        memset(&perf_events, 0, sizeof(perf_events));
+
+        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) {
+                perf_events[cpu] = kcalloc(num_counters,
+                                sizeof(struct perf_event *), GFP_KERNEL);
+                if (!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;
+}