+/*
+ * (C) Copyright 2009-2011 -
+ * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * LTTng function tracer integration module.
+ *
+ * Dual LGPL v2.1/GPL v2 license.
+ */
+
+#include <linux/module.h>
+#include <linux/ftrace.h>
+#include <linux/slab.h>
+#include "../ltt-events.h"
+#include "../wrapper/ringbuffer/frontend_types.h"
+#include "../ltt-tracer.h"
+
+static
+int lttng_ftrace_handler(unsigned long ip, unsigned long parent_ip, void **data)
+{
+ struct ltt_event *event = *data;
+ struct ltt_channel *chan = event->chan;
+ struct lib_ring_buffer_ctx ctx;
+ struct {
+ unsigned long ip;
+ unsigned long parent_ip;
+ } payload;
+ int ret;
+
+ if (!ACCESS_ONCE(chan->session->active))
+ return 0;
+ lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL,
+ sizeof(payload), ltt_alignof(payload), -1);
+ ret = chan->ops->event_reserve(&ctx);
+ if (ret < 0)
+ return 0;
+ payload.ip = ip;
+ payload.parent_ip = parent_ip;
+ lib_ring_buffer_align_ctx(&ctx, ltt_alignof(payload));
+ chan->ops->event_write(&ctx, &payload, sizeof(payload));
+ chan->ops->event_commit(&ctx);
+ return 0;
+}
+
+/*
+ * Create event description
+ */
+static
+int lttng_create_ftrace_event(const char *name, struct ltt_event *event)
+{
+ struct lttng_event_field *fields;
+ struct lttng_event_desc *desc;
+ int ret;
+
+ desc = kzalloc(sizeof(*event->desc), GFP_KERNEL);
+ if (!desc)
+ return -ENOMEM;
+ desc->name = kstrdup(name, GFP_KERNEL);
+ if (!desc->name) {
+ ret = -ENOMEM;
+ goto error_str;
+ }
+ desc->nr_fields = 2;
+ desc->fields = fields =
+ kzalloc(2 * sizeof(struct lttng_event_field), GFP_KERNEL);
+ fields[0].name = "ip";
+ fields[0].type.atype = atype_integer;
+ fields[0].type.u.basic.integer.size = sizeof(unsigned long);
+ fields[0].type.u.basic.integer.alignment = ltt_alignof(unsigned long);
+ fields[0].type.u.basic.integer.signedness = 0;
+ fields[0].type.u.basic.integer.reverse_byte_order = 0;
+ fields[0].type.u.basic.integer.base = 16;
+ fields[0].type.u.basic.integer.encoding = lttng_encode_none;
+
+ fields[1].name = "parent_ip";
+ fields[1].type.atype = atype_integer;
+ fields[1].type.u.basic.integer.size = sizeof(unsigned long);
+ fields[1].type.u.basic.integer.alignment = ltt_alignof(unsigned long);
+ fields[1].type.u.basic.integer.signedness = 0;
+ fields[1].type.u.basic.integer.reverse_byte_order = 0;
+ fields[1].type.u.basic.integer.base = 16;
+ fields[1].type.u.basic.integer.encoding = lttng_encode_none;
+
+ event->desc = desc;
+
+ return 0;
+
+error_str:
+ kfree(desc);
+ return ret;
+}
+
+static
+struct ftrace_probe_ops lttng_ftrace_ops = {
+ .func = lttng_ftrace_handler,
+};
+
+int lttng_ftrace_register(const char *name,
+ const char *symbol_name,
+ struct ltt_event *event)
+{
+ int ret;
+
+ ret = lttng_create_ftrace_event(name, event);
+ if (ret)
+ goto error;
+
+ event->u.ftrace.symbol_name = kstrdup(name, GFP_KERNEL);
+ if (!event->u.ftrace.symbol_name)
+ goto name_error;
+
+ ret = register_ftrace_function_probe(symbol_name,
+ <tng_ftrace_ops, event);
+ if (ret)
+ goto register_error;
+ return 0;
+
+register_error:
+ kfree(event->u.ftrace.symbol_name);
+name_error:
+ kfree(event->desc->name);
+ kfree(event->desc);
+error:
+ return ret;
+}
+EXPORT_SYMBOL_GPL(lttng_ftrace_register);
+
+void lttng_ftrace_unregister(struct ltt_event *event)
+{
+ unregister_ftrace_function_probe(event->u.ftrace.symbol_name,
+ <tng_ftrace_ops, event);
+ kfree(event->u.ftrace.symbol_name);
+ kfree(event->desc->name);
+ kfree(event->desc);
+}
+EXPORT_SYMBOL_GPL(lttng_ftrace_unregister);
+
+MODULE_LICENSE("GPL and additional rights");
+MODULE_AUTHOR("Mathieu Desnoyers");
+MODULE_DESCRIPTION("Linux Trace Toolkit Ftrace Support");