From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Thu, 19 May 2011 02:05:24 +0000 (-0400)
Subject: Add event description for each kprobe event
X-Git-Tag: v2.0-pre1~142
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=f17701fb89c69c3950c22a0c20d0233092e7d6ed;p=lttng-modules.git

Add event description for each kprobe event

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/ltt-debugfs-abi.h b/ltt-debugfs-abi.h
index ecbd5413..411c37b7 100644
--- a/ltt-debugfs-abi.h
+++ b/ltt-debugfs-abi.h
@@ -16,6 +16,7 @@
 enum lttng_kernel_instrumentation {
 	LTTNG_KERNEL_TRACEPOINTS,
 	LTTNG_KERNEL_KPROBES,
+	LTTNG_KERNEL_FUNCTION_TRACER,
 };
 
 /*
@@ -40,13 +41,18 @@ struct lttng_kernel_kprobe {
 	char symbol_name[LTTNG_KPROBE_SYM_NAME_LEN];
 };
 
+struct lttng_kernel_function_tracer {
+	char symbol_name[LTTNG_KPROBE_SYM_NAME_LEN];
+};
+
 struct lttng_kernel_event {
 	enum lttng_kernel_instrumentation instrumentation;
 	/* Per instrumentation type configuration */
 	union {
 		struct lttng_kernel_kprobe kprobe;
+		struct lttng_kernel_function_tracer ftrace;
 	} u;
-	char name[];
+	char name[];	/* event name */
 };
 
 struct lttng_kernel_tracer_version {
diff --git a/ltt-events.c b/ltt-events.c
index ec5d6830..29d0ed74 100644
--- a/ltt-events.c
+++ b/ltt-events.c
@@ -237,24 +237,13 @@ struct ltt_event *ltt_event_create(struct ltt_channel *chan, char *name,
 			goto register_error;
 		break;
 	case LTTNG_KERNEL_KPROBES:
-		event->u.kprobe.kp.pre_handler = lttng_kprobes_handler_pre;
-		event->u.kprobe.symbol_name =
-			kzalloc(LTTNG_KPROBE_SYM_NAME_LEN * sizeof(char),
-				GFP_KERNEL);
-		if (!event->u.kprobe.symbol_name)
-			goto register_error;
-		memcpy(event->u.kprobe.symbol_name,
-		       event_param->u.kprobe.symbol_name,
-		       LTTNG_KPROBE_SYM_NAME_LEN * sizeof(char));
-		event->u.kprobe.kp.symbol_name =
-			event->u.kprobe.symbol_name;
-		event->u.kprobe.kp.offset = event_param->u.kprobe.offset;
-		event->u.kprobe.kp.addr = (void *) event_param->u.kprobe.addr;
-		ret = register_kprobe(&event->u.kprobe.kp);
-		if (ret) {
-			kfree(event->u.kprobe.symbol_name);
+		ret = lttng_kprobes_register(name,
+				event_param->u.kprobe.symbol_name,
+				event_param->u.kprobe.offset,
+				event_param->u.kprobe.addr,
+				event);
+		if (ret)
 			goto register_error;
-		}
 		break;
 	default:
 		WARN_ON_ONCE(1);
@@ -294,8 +283,7 @@ int _ltt_event_unregister(struct ltt_event *event)
 			return ret;
 		break;
 	case LTTNG_KERNEL_KPROBES:
-		unregister_kprobe(&event->u.kprobe.kp);
-		kfree(event->u.kprobe.symbol_name);
+		lttng_kprobes_unregister(event);
 		ret = 0;
 		break;
 	default:
diff --git a/ltt-events.h b/ltt-events.h
index 42e12c0a..a26638c4 100644
--- a/ltt-events.h
+++ b/ltt-events.h
@@ -104,7 +104,7 @@ struct lttng_enum {
 
 struct lttng_event_field {
 	const char *name;
-	const struct lttng_type type;
+	struct lttng_type type;
 };
 
 struct lttng_event_desc {
@@ -127,7 +127,7 @@ struct lttng_probe_desc {
 struct ltt_event {
 	unsigned int id;
 	struct ltt_channel *chan;
-	const struct lttng_event_desc *desc;
+	struct lttng_event_desc *desc;
 	void *filter;
 	enum lttng_kernel_instrumentation instrumentation;
 	union {
@@ -234,6 +234,11 @@ void ltt_event_put(const struct lttng_event_desc *desc);
 int ltt_probes_init(void);
 void ltt_probes_exit(void);
 
-void lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs);
+int lttng_kprobes_register(const char *name,
+		const char *symbol_name,
+		uint64_t offset,
+		uint64_t addr,
+		struct ltt_event *event);
+void lttng_kprobes_unregister(struct ltt_event *event);
 
 #endif /* _LTT_EVENTS_H */
diff --git a/probes/lttng-kprobes.c b/probes/lttng-kprobes.c
index eb6e16a0..bee935f7 100644
--- a/probes/lttng-kprobes.c
+++ b/probes/lttng-kprobes.c
@@ -9,11 +9,13 @@
 
 #include <linux/module.h>
 #include <linux/kprobes.h>
+#include <linux/slab.h>
 #include "../ltt-events.h"
 #include "../wrapper/ringbuffer/frontend_types.h"
 #include "../ltt-tracer.h"
 
-void lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs)
+static
+int lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs)
 {
 	struct ltt_event *event =
 		container_of(p, struct ltt_event, u.kprobe.kp);
@@ -23,17 +25,101 @@ void lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs)
 	unsigned long data = (unsigned long) p->addr;
 
 	if (!ACCESS_ONCE(chan->session->active))
-		return;
+		return 0;
 	lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, sizeof(data),
 				 ltt_alignof(data), -1);
 	ret = chan->ops->event_reserve(&ctx);
 	if (ret < 0)
-		return;
+		return 0;
 	lib_ring_buffer_align_ctx(&ctx, ltt_alignof(data));
 	chan->ops->event_write(&ctx, &data, sizeof(data));
 	chan->ops->event_commit(&ctx);
+	return 0;
 }
-EXPORT_SYMBOL_GPL(lttng_kprobes_handler_pre);
+
+/*
+ * Create event description
+ */
+static
+int lttng_create_kprobe_event(const char *name, struct ltt_event *event)
+{
+	struct lttng_event_field *field;
+	int ret;
+
+	event->desc = kzalloc(sizeof(*event->desc), GFP_KERNEL);
+	if (!event->desc)
+		return -ENOMEM;
+	event->desc->name = kstrdup(name, GFP_KERNEL);
+	if (!event->desc->name) {
+		ret = -ENOMEM;
+		goto error_str;
+	}
+	event->desc->nr_fields = 1;
+	event->desc->fields = field =
+		kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL);
+	field->name = "ip";
+	field->type.atype = atype_integer;
+	field->type.u.basic.integer.size = sizeof(unsigned long);
+	field->type.u.basic.integer.alignment = ltt_alignof(unsigned long);
+	field->type.u.basic.integer.signedness = 0;
+	field->type.u.basic.integer.reverse_byte_order = 0;
+
+	return 0;
+
+error_str:
+	kfree(event->desc);
+	return ret;
+}
+
+int lttng_kprobes_register(const char *name,
+			   const char *symbol_name,
+			   uint64_t offset,
+			   uint64_t addr,
+			   struct ltt_event *event)
+{
+	int ret;
+
+	ret = lttng_create_kprobe_event(name, event);
+	if (ret)
+		goto error;
+	memset(&event->u.kprobe.kp, 0, sizeof(event->u.kprobe.kp));
+	event->u.kprobe.kp.pre_handler = lttng_kprobes_handler_pre;
+	event->u.kprobe.symbol_name =
+		kzalloc(LTTNG_KPROBE_SYM_NAME_LEN * sizeof(char),
+			GFP_KERNEL);
+	if (!event->u.kprobe.symbol_name) {
+		ret = -ENOMEM;
+		goto name_error;
+	}
+	memcpy(event->u.kprobe.symbol_name, symbol_name,
+	       LTTNG_KPROBE_SYM_NAME_LEN * sizeof(char));
+	event->u.kprobe.kp.symbol_name =
+		event->u.kprobe.symbol_name;
+	event->u.kprobe.kp.offset = offset;
+	event->u.kprobe.kp.addr = (void *) addr;
+	ret = register_kprobe(&event->u.kprobe.kp);
+	if (ret)
+		goto register_error;
+	return 0;
+
+register_error:
+	kfree(event->u.kprobe.symbol_name);
+name_error:
+	kfree(event->desc->name);
+	kfree(event->desc);
+error:
+	return ret;
+}
+EXPORT_SYMBOL_GPL(lttng_kprobes_register);
+
+void lttng_kprobes_unregister(struct ltt_event *event)
+{
+	unregister_kprobe(&event->u.kprobe.kp);
+	kfree(event->u.kprobe.symbol_name);
+	kfree(event->desc->name);
+	kfree(event->desc);
+}
+EXPORT_SYMBOL_GPL(lttng_kprobes_unregister);
 
 MODULE_LICENSE("GPL and additional rights");
 MODULE_AUTHOR("Mathieu Desnoyers");