Mass rename: ltt_*/ltt-* to LTTNG_*/LTTNG-*

[lttng-modules.git] / probes / lttng-ftrace.c

diff --git a/probes/lttng-ftrace.c b/probes/lttng-ftrace.c
index 7c4fc9f55d78f5fc98898cd45af8a630b37e90ae..2a939216ef5e3233edc484b66dcb288837f42a99 100644 (file)
--- a/probes/lttng-ftrace.c
+++ b/probes/lttng-ftrace.c
@@ -11,22 +11,26 @@
  * Ftrace function tracer does not seem to provide synchronization between probe
  * teardown and callback execution. Therefore, we make this module permanently
  * loaded (unloadable).
+ *
+ * TODO: Move to register_ftrace_function() (which is exported for
+ * modules) for Linux >= 3.0. It is faster (only enables the selected
+ * functions), and will stay there.
  */
 
 #include <linux/module.h>
 #include <linux/ftrace.h>
 #include <linux/slab.h>
-#include "../ltt-events.h"
+#include "../lttng-events.h"
 #include "../wrapper/ringbuffer/frontend_types.h"
 #include "../wrapper/ftrace.h"
 #include "../wrapper/vmalloc.h"
-#include "../ltt-tracer.h"
+#include "../lttng-tracer.h"
 
 static
 void lttng_ftrace_handler(unsigned long ip, unsigned long parent_ip, void **data)
 {
-       struct ltt_event *event = *data;
-       struct ltt_channel *chan = event->chan;
+       struct lttng_event *event = *data;
+       struct lttng_channel *chan = event->chan;
        struct lib_ring_buffer_ctx ctx;
        struct {
                unsigned long ip;
@@ -34,16 +38,21 @@ void lttng_ftrace_handler(unsigned long ip, unsigned long parent_ip, void **data
        } payload;
        int ret;
 
-       if (!ACCESS_ONCE(chan->session->active))
+       if (unlikely(!ACCESS_ONCE(chan->session->active)))
+               return;
+       if (unlikely(!ACCESS_ONCE(chan->enabled)))
                return;
-       lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL,
-                                sizeof(payload), ltt_alignof(payload), -1);
+       if (unlikely(!ACCESS_ONCE(event->enabled)))
+               return;
+
+       lib_ring_buffer_ctx_init(&ctx, chan->chan, event,
+                                sizeof(payload), lttng_alignof(payload), -1);
        ret = chan->ops->event_reserve(&ctx, event->id);
        if (ret < 0)
                return;
        payload.ip = ip;
        payload.parent_ip = parent_ip;
-       lib_ring_buffer_align_ctx(&ctx, ltt_alignof(payload));
+       lib_ring_buffer_align_ctx(&ctx, lttng_alignof(payload));
        chan->ops->event_write(&ctx, &payload, sizeof(payload));
        chan->ops->event_commit(&ctx);
        return;
@@ -53,7 +62,7 @@ void lttng_ftrace_handler(unsigned long ip, unsigned long parent_ip, void **data
  * Create event description
  */
 static
-int lttng_create_ftrace_event(const char *name, struct ltt_event *event)
+int lttng_create_ftrace_event(const char *name, struct lttng_event *event)
 {
        struct lttng_event_field *fields;
        struct lttng_event_desc *desc;
@@ -77,8 +86,8 @@ int lttng_create_ftrace_event(const char *name, struct ltt_event *event)
        fields[0].name = "ip";
        fields[0].type.atype = atype_integer;
        fields[0].type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT;
-       fields[0].type.u.basic.integer.alignment = ltt_alignof(unsigned long) * CHAR_BIT;
-       fields[0].type.u.basic.integer.signedness = 0;
+       fields[0].type.u.basic.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT;
+       fields[0].type.u.basic.integer.signedness = is_signed_type(unsigned long);
        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;
@@ -86,12 +95,13 @@ int lttng_create_ftrace_event(const char *name, struct ltt_event *event)
        fields[1].name = "parent_ip";
        fields[1].type.atype = atype_integer;
        fields[1].type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT;
-       fields[1].type.u.basic.integer.alignment = ltt_alignof(unsigned long) * CHAR_BIT;
-       fields[1].type.u.basic.integer.signedness = 0;
+       fields[1].type.u.basic.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT;
+       fields[1].type.u.basic.integer.signedness = is_signed_type(unsigned long);
        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;
 
+       desc->owner = THIS_MODULE;
        event->desc = desc;
 
        return 0;
@@ -110,7 +120,7 @@ struct ftrace_probe_ops lttng_ftrace_ops = {
 
 int lttng_ftrace_register(const char *name,
                          const char *symbol_name,
-                         struct ltt_event *event)
+                         struct lttng_event *event)
 {
        int ret;
 
@@ -118,7 +128,7 @@ int lttng_ftrace_register(const char *name,
        if (ret)
                goto error;
 
-       event->u.ftrace.symbol_name = kstrdup(name, GFP_KERNEL);
+       event->u.ftrace.symbol_name = kstrdup(symbol_name, GFP_KERNEL);
        if (!event->u.ftrace.symbol_name)
                goto name_error;
 
@@ -127,7 +137,7 @@ int lttng_ftrace_register(const char *name,
 
        ret = wrapper_register_ftrace_function_probe(event->u.ftrace.symbol_name,
                        &lttng_ftrace_ops, event);
-       if (ret)
+       if (ret < 0)
                goto register_error;
        return 0;
 
@@ -141,18 +151,22 @@ error:
 }
 EXPORT_SYMBOL_GPL(lttng_ftrace_register);
 
-void lttng_ftrace_unregister(struct ltt_event *event)
+void lttng_ftrace_unregister(struct lttng_event *event)
 {
        wrapper_unregister_ftrace_function_probe(event->u.ftrace.symbol_name,
                        &lttng_ftrace_ops, event);
+}
+EXPORT_SYMBOL_GPL(lttng_ftrace_unregister);
+
+void lttng_ftrace_destroy_private(struct lttng_event *event)
+{
        kfree(event->u.ftrace.symbol_name);
        kfree(event->desc->fields);
        kfree(event->desc->name);
        kfree(event->desc);
 }
-EXPORT_SYMBOL_GPL(lttng_ftrace_unregister);
+EXPORT_SYMBOL_GPL(lttng_ftrace_destroy_private);
 
-/* This module is permanent. */
 int lttng_ftrace_init(void)
 {
        wrapper_vmalloc_sync_all();
@@ -160,6 +174,15 @@ int lttng_ftrace_init(void)
 }
 module_init(lttng_ftrace_init)
 
+/*
+ * Ftrace takes care of waiting for a grace period (RCU sched) at probe
+ * unregistration, and disables preemption around probe call.
+ */
+void lttng_ftrace_exit(void)
+{
+}
+module_exit(lttng_ftrace_exit)
+
 MODULE_LICENSE("GPL and additional rights");
 MODULE_AUTHOR("Mathieu Desnoyers");
 MODULE_DESCRIPTION("Linux Trace Toolkit Ftrace Support");