+/*
+ * (C) Copyright 2009-2011 -
+ * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * LTTng performance monitoring counters (perf-counters) integration module.
+ *
+ * Dual LGPL v2.1/GPL v2 license.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/perf_event.h>
+#include <linux/list.h>
+#include <linux/string.h>
+#include "ltt-events.h"
+#include "wrapper/ringbuffer/frontend_types.h"
+#include "wrapper/vmalloc.h"
+#include "ltt-tracer.h"
+
+/*
+ * TODO: Add CPU hotplug support.
+ */
+
+static DEFINE_MUTEX(perf_counter_mutex);
+static LIST_HEAD(perf_counter_contexts);
+
+static
+size_t perf_counter_get_size(size_t offset)
+{
+ size_t size = 0;
+
+ size += lib_ring_buffer_align(offset, ltt_alignof(uint64_t));
+ size += sizeof(uint64_t);
+ return size;
+}
+
+static
+void perf_counter_record(struct lttng_ctx_field *field,
+ struct lib_ring_buffer_ctx *ctx,
+ struct ltt_channel *chan)
+{
+ struct perf_event *event;
+ uint64_t value;
+
+ event = field->u.perf_counter.e[ctx->cpu];
+ event->pmu->read(event);
+ value = local64_read(&event->count);
+ lib_ring_buffer_align_ctx(ctx, ltt_alignof(value));
+ chan->ops->event_write(ctx, &value, sizeof(value));
+}
+
+static
+void overflow_callback(struct perf_event *event, int nmi,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+}
+
+static
+void lttng_destroy_perf_counter_field(struct lttng_ctx_field *field)
+{
+ struct perf_event **events = field->u.perf_counter.e;
+ int cpu;
+
+ mutex_lock(&perf_counter_mutex);
+ list_del(&field->u.perf_counter.head);
+ for_each_online_cpu(cpu)
+ perf_event_release_kernel(events[cpu]);
+ mutex_unlock(&perf_counter_mutex);
+ kfree(field->event_field.name);
+ kfree(field->u.perf_counter.attr);
+ kfree(events);
+}
+
+int lttng_add_perf_counter_to_ctx(uint32_t type,
+ uint64_t config,
+ const char *name,
+ struct lttng_ctx **ctx)
+{
+ struct lttng_ctx_field *field;
+ struct perf_event **events;
+ struct perf_event_attr *attr;
+ int ret;
+ int cpu;
+ char *name_alloc;
+
+ events = kzalloc(num_possible_cpus() * sizeof(*events), GFP_KERNEL);
+ if (!events)
+ return -ENOMEM;
+
+ attr = kzalloc(sizeof(*field->u.perf_counter.attr), GFP_KERNEL);
+ if (!attr) {
+ ret = -ENOMEM;
+ goto error_attr;
+ }
+
+ attr->type = type;
+ attr->config = config;
+ attr->size = sizeof(struct perf_event_attr);
+ attr->pinned = 1;
+ attr->disabled = 0;
+
+ mutex_lock(&perf_counter_mutex);
+
+ for_each_online_cpu(cpu) {
+ events[cpu] = perf_event_create_kernel_counter(attr,
+ cpu, NULL, overflow_callback);
+ if (!events[cpu]) {
+ ret = -EINVAL;
+ goto error;
+ }
+ }
+
+ name_alloc = kstrdup(name, GFP_KERNEL);
+ if (!field->event_field.name)
+ goto name_alloc_error;
+
+ field = lttng_append_context(ctx);
+ if (!field) {
+ ret = -ENOMEM;
+ goto error;
+ }
+ field->destroy = lttng_destroy_perf_counter_field;
+
+ field->event_field.name = name_alloc;
+ field->event_field.type.atype = atype_integer;
+ field->event_field.type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT;
+ field->event_field.type.u.basic.integer.alignment = ltt_alignof(unsigned long) * CHAR_BIT;
+ field->event_field.type.u.basic.integer.signedness = is_signed_type(unsigned long);
+ field->event_field.type.u.basic.integer.reverse_byte_order = 0;
+ field->event_field.type.u.basic.integer.base = 10;
+ field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
+ field->get_size = perf_counter_get_size;
+ field->record = perf_counter_record;
+ field->u.perf_counter.e = events;
+ field->u.perf_counter.attr = attr;
+
+ list_add(&field->u.perf_counter.head, &perf_counter_contexts);
+ mutex_unlock(&perf_counter_mutex);
+
+ wrapper_vmalloc_sync_all();
+ return 0;
+
+error:
+ kfree(name_alloc);
+name_alloc_error:
+ for_each_online_cpu(cpu) {
+ if (events[cpu])
+ perf_event_release_kernel(events[cpu]);
+ }
+ mutex_unlock(&perf_counter_mutex);
+ kfree(attr);
+error_attr:
+ kfree(events);
+ return ret;
+}
+
+MODULE_LICENSE("GPL and additional rights");
+MODULE_AUTHOR("Mathieu Desnoyers");
+MODULE_DESCRIPTION("Linux Trace Toolkit Perf Support");