tracing: event trigger updates

index ce0ed8a..3afa716 100644
@@ -929,12 +929,20 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
 	struct ring_buffer *buffer;
 	int size, dsize, pc;
 	unsigned long irq_flags;
+	unsigned long eflags;
+	enum event_trigger_type tt = ETT_NONE;
 	struct ftrace_event_call *call = &tk->tp.call;
 
 	WARN_ON(call != ftrace_file->event_call);
 
-	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
-		return;
+	eflags = ftrace_file->flags;
+
+	if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) {
+		if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE)
+			event_triggers_call(ftrace_file, NULL);
+		if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED)
+			return;
+	}
 
 	local_save_flags(irq_flags);
 	pc = preempt_count();

@@ -952,9 +960,16 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
 	entry->ip = (unsigned long)tk->rp.kp.addr;
 	store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
 
-	if (!filter_check_discard(ftrace_file, entry, buffer, event))
+	if (eflags & FTRACE_EVENT_FL_TRIGGER_COND)
+		tt = event_triggers_call(ftrace_file, entry);
+
+	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
+		ring_buffer_discard_commit(buffer, event);
+	else if (!filter_check_discard(ftrace_file, entry, buffer, event))
 		trace_buffer_unlock_commit_regs(buffer, event,
 						irq_flags, pc, regs);
+	if (tt)
+		event_triggers_post_call(ftrace_file, tt);
 }
 
 static __kprobes void

@@ -977,12 +992,20 @@ __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
 	struct ring_buffer *buffer;
 	int size, pc, dsize;
 	unsigned long irq_flags;
+	unsigned long eflags;
+	enum event_trigger_type tt = ETT_NONE;
 	struct ftrace_event_call *call = &tk->tp.call;
 
 	WARN_ON(call != ftrace_file->event_call);
 
-	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
-		return;
+	eflags = ftrace_file->flags;
+
+	if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) {
+		if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE)
+			event_triggers_call(ftrace_file, NULL);
+		if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED)
+			return;
+	}
 
 	local_save_flags(irq_flags);
 	pc = preempt_count();

@@ -1001,9 +1024,16 @@ __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
 	entry->ret_ip = (unsigned long)ri->ret_addr;
 	store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
 
-	if (!filter_check_discard(ftrace_file, entry, buffer, event))
+	if (eflags & FTRACE_EVENT_FL_TRIGGER_COND)
+		tt = event_triggers_call(ftrace_file, entry);
+
+	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
+		ring_buffer_discard_commit(buffer, event);
+	else if (!filter_check_discard(ftrace_file, entry, buffer, event))
 		trace_buffer_unlock_commit_regs(buffer, event,
 						irq_flags, pc, regs);
+	if (tt)
+		event_triggers_post_call(ftrace_file, tt);
 }
 
 static __kprobes void

index fdd955f..a4acf9b 100644
@@ -306,7 +306,7 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
 	struct syscall_trace_enter *entry;
 	struct syscall_metadata *sys_data;
 	struct ring_buffer_event *event;
-	enum event_trigger_type __tt = ETT_NONE;
+	enum event_trigger_type tt = ETT_NONE;
 	struct ring_buffer *buffer;
 	unsigned long irq_flags;
 	unsigned long eflags;

@@ -352,15 +352,15 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
 	syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
 
 	if (eflags & FTRACE_EVENT_FL_TRIGGER_COND)
-		__tt = event_triggers_call(ftrace_file, entry);
+		tt = event_triggers_call(ftrace_file, entry);
 
 	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
 		ring_buffer_discard_commit(buffer, event);
 	else if (!filter_check_discard(ftrace_file, entry, buffer, event))
 		trace_current_buffer_unlock_commit(buffer, event,
 						   irq_flags, pc);
-	if (__tt)
-		event_triggers_post_call(ftrace_file, __tt);
+	if (tt)
+		event_triggers_post_call(ftrace_file, tt);
 }
 
 static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)

@@ -370,7 +370,7 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
 	struct syscall_trace_exit *entry;
 	struct syscall_metadata *sys_data;
 	struct ring_buffer_event *event;
-	enum event_trigger_type __tt = ETT_NONE;
+	enum event_trigger_type tt = ETT_NONE;
 	struct ring_buffer *buffer;
 	unsigned long irq_flags;
 	unsigned long eflags;

@@ -414,15 +414,15 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
 	entry->ret = syscall_get_return_value(current, regs);
 
 	if (eflags & FTRACE_EVENT_FL_TRIGGER_COND)
-		__tt = event_triggers_call(ftrace_file, entry);
+		tt = event_triggers_call(ftrace_file, entry);
 
 	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
 		ring_buffer_discard_commit(buffer, event);
 	else if (!filter_check_discard(ftrace_file, entry, buffer, event))
 		trace_current_buffer_unlock_commit(buffer, event,
 						   irq_flags, pc);
-	if (__tt)
-		event_triggers_post_call(ftrace_file, __tt);
+	if (tt)
+		event_triggers_post_call(ftrace_file, tt);
 }
 
 static int reg_event_syscall_enter(struct ftrace_event_file *file,

index f6dd115..a53e0da 100644
@@ -742,13 +742,16 @@ traceon_trigger(struct event_trigger_data *data)
 static void
 traceon_count_trigger(struct event_trigger_data *data)
 {
+	if (tracing_is_on())
+		return;
+
 	if (!data->count)
 		return;
 
 	if (data->count != -1)
 		(data->count)--;
 
-	traceon_trigger(data);
+	tracing_on();
 }
 
 static void

@@ -763,13 +766,16 @@ traceoff_trigger(struct event_trigger_data *data)
 static void
 traceoff_count_trigger(struct event_trigger_data *data)
 {
+	if (!tracing_is_on())
+		return;
+
 	if (!data->count)
 		return;
 
 	if (data->count != -1)
 		(data->count)--;
 
-	traceoff_trigger(data);
+	tracing_off();
 }
 
 static int

index 03d2db2..4e4cc28 100644
@@ -370,6 +370,123 @@ extern enum event_trigger_type event_triggers_call(struct ftrace_event_file *fil
 extern void event_triggers_post_call(struct ftrace_event_file *file,
 				     enum event_trigger_type tt);
 
+/**
+ * ftrace_trigger_soft_disabled - do triggers and test if soft disabled
+ * @file: The file pointer of the event to test
+ *
+ * If any triggers without filters are attached to this event, they
+ * will be called here. If the event is soft disabled and has no
+ * triggers that require testing the fields, it will return true,
+ * otherwise false.
+ */
+static inline bool
+ftrace_trigger_soft_disabled(struct ftrace_event_file *file)
+{
+	unsigned long eflags = file->flags;
+
+	if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) {
+		if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE)
+			event_triggers_call(file, NULL);
+		if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED)
+			return true;
+	}
+	return false;
+}
+
+/*
+ * Helper function for event_trigger_unlock_commit{_regs}().
+ * If there are event triggers attached to this event that requires
+ * filtering against its fields, then they wil be called as the
+ * entry already holds the field information of the current event.
+ *
+ * It also checks if the event should be discarded or not.
+ * It is to be discarded if the event is soft disabled and the
+ * event was only recorded to process triggers, or if the event
+ * filter is active and this event did not match the filters.
+ *
+ * Returns true if the event is discarded, false otherwise.
+ */
+static inline bool
+__event_trigger_test_discard(struct ftrace_event_file *file,
+			     struct ring_buffer *buffer,
+			     struct ring_buffer_event *event,
+			     void *entry,
+			     enum event_trigger_type *tt)
+{
+	unsigned long eflags = file->flags;
+
+	if (eflags & FTRACE_EVENT_FL_TRIGGER_COND)
+		*tt = event_triggers_call(file, entry);
+
+	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags))
+		ring_buffer_discard_commit(buffer, event);
+	else if (!filter_check_discard(file, entry, buffer, event))
+		return false;
+
+	return true;
+}
+
+/**
+ * event_trigger_unlock_commit - handle triggers and finish event commit
+ * @file: The file pointer assoctiated to the event
+ * @buffer: The ring buffer that the event is being written to
+ * @event: The event meta data in the ring buffer
+ * @entry: The event itself
+ * @irq_flags: The state of the interrupts at the start of the event
+ * @pc: The state of the preempt count at the start of the event.
+ *
+ * This is a helper function to handle triggers that require data
+ * from the event itself. It also tests the event against filters and
+ * if the event is soft disabled and should be discarded.
+ */
+static inline void
+event_trigger_unlock_commit(struct ftrace_event_file *file,
+			    struct ring_buffer *buffer,
+			    struct ring_buffer_event *event,
+			    void *entry, unsigned long irq_flags, int pc)
+{
+	enum event_trigger_type tt = ETT_NONE;
+
+	if (!__event_trigger_test_discard(file, buffer, event, entry, &tt))
+		trace_buffer_unlock_commit(buffer, event, irq_flags, pc);
+
+	if (tt)
+		event_triggers_post_call(file, tt);
+}
+
+/**
+ * event_trigger_unlock_commit_regs - handle triggers and finish event commit
+ * @file: The file pointer assoctiated to the event
+ * @buffer: The ring buffer that the event is being written to
+ * @event: The event meta data in the ring buffer
+ * @entry: The event itself
+ * @irq_flags: The state of the interrupts at the start of the event
+ * @pc: The state of the preempt count at the start of the event.
+ *
+ * This is a helper function to handle triggers that require data
+ * from the event itself. It also tests the event against filters and
+ * if the event is soft disabled and should be discarded.
+ *
+ * Same as event_trigger_unlock_commit() but calls
+ * trace_buffer_unlock_commit_regs() instead of trace_buffer_unlock_commit().
+ */
+static inline void
+event_trigger_unlock_commit_regs(struct ftrace_event_file *file,
+				 struct ring_buffer *buffer,
+				 struct ring_buffer_event *event,
+				 void *entry, unsigned long irq_flags, int pc,
+				 struct pt_regs *regs)
+{
+	enum event_trigger_type tt = ETT_NONE;
+
+	if (!__event_trigger_test_discard(file, buffer, event, entry, &tt))
+		trace_buffer_unlock_commit_regs(buffer, event,
+						irq_flags, pc, regs);
+
+	if (tt)
+		event_triggers_post_call(file, tt);
+}
+
 enum {
 	FILTER_OTHER = 0,
 	FILTER_STATIC_STRING,

index 0962968..1a8b28d 100644
@@ -546,8 +546,6 @@ ftrace_raw_event_##call(void *__data, proto)				\
 	struct ftrace_event_file *ftrace_file = __data;			\
 	struct ftrace_event_call *event_call = ftrace_file->event_call;	\
 	struct ftrace_data_offsets_##call __maybe_unused __data_offsets;\
-	unsigned long eflags = ftrace_file->flags;			\
-	enum event_trigger_type __tt = ETT_NONE;			\
 	struct ring_buffer_event *event;				\
 	struct ftrace_raw_##call *entry;				\
 	struct ring_buffer *buffer;					\

@@ -555,12 +553,8 @@ ftrace_raw_event_##call(void *__data, proto)				\
 	int __data_size;						\
 	int pc;								\
 									\
-	if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) {			\
-		if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE)		\
-			event_triggers_call(ftrace_file, NULL);		\
-		if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED)		\
-			return;						\
-	}								\
+	if (ftrace_trigger_soft_disabled(ftrace_file))			\
+		return;							\
 									\
 	local_save_flags(irq_flags);					\
 	pc = preempt_count();						\

@@ -579,17 +573,8 @@ ftrace_raw_event_##call(void *__data, proto)				\
 									\
 	{ assign; }							\
 									\
-	if (eflags & FTRACE_EVENT_FL_TRIGGER_COND)			\
-		__tt = event_triggers_call(ftrace_file, entry);		\
-									\
-	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT,                 \
-		     &ftrace_file->flags))                              \
-		ring_buffer_discard_commit(buffer, event);              \
-	else if (!filter_check_discard(ftrace_file, entry, buffer, event)) \
-		trace_buffer_unlock_commit(buffer, event, irq_flags, pc); \
-									\
-	if (__tt)							\
-		event_triggers_post_call(ftrace_file, __tt);		\
+	event_trigger_unlock_commit(ftrace_file, buffer, event, entry, \
+				    irq_flags, pc);		       \
 }
 /*
  * The ftrace_test_probe is compiled out, it is only here as a build time check

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88 lines not on this page · raw message

index a53e0da..8efbb69 100644
@@ -115,10 +115,15 @@ event_triggers_post_call(struct ftrace_event_file *file,
 }
 EXPORT_SYMBOL_GPL(event_triggers_post_call);
 
+#define SHOW_AVAILABLE_TRIGGERS	(void *)(1UL)
+
 static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
 {
 	struct ftrace_event_file *event_file = event_file_data(m->private);
 
+	if (t == SHOW_AVAILABLE_TRIGGERS)
+		return NULL;
+
 	return seq_list_next(t, &event_file->triggers, pos);
 }
 

@@ -132,6 +137,9 @@ static void *trigger_start(struct seq_file *m, loff_t *pos)
 	if (unlikely(!event_file))
 		return ERR_PTR(-ENODEV);
 
+	if (list_empty(&event_file->triggers))
+		return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;
+
 	return seq_list_start(&event_file->triggers, *pos);
 }
 

@@ -143,6 +151,18 @@ static void trigger_stop(struct seq_file *m, void *t)
 static int trigger_show(struct seq_file *m, void *v)
 {
 	struct event_trigger_data *data;
+	struct event_command *p;
+
+	if (v == SHOW_AVAILABLE_TRIGGERS) {
+		seq_puts(m, "# Available triggers:\n");
+		seq_putc(m, '#');
+		mutex_lock(&trigger_cmd_mutex);
+		list_for_each_entry_reverse(p, &trigger_commands, list)
+			seq_printf(m, " %s", p->name);
+		seq_putc(m, '\n');
+		mutex_unlock(&trigger_cmd_mutex);
+		return 0;
+	}
 
 	data = list_entry(v, struct event_trigger_data, list);
 	data->ops->print(m, data->ops, data);