Merge tag 'trace-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "This pull request has a new feature to ftrace, namely the trace event
  triggers by Tom Zanussi.  A trigger is a way to enable an action when
  an event is hit.  The actions are:

   o  trace on/off - enable or disable tracing
   o  snapshot     - save the current trace buffer in the snapshot
   o  stacktrace   - dump the current stack trace to the ringbuffer
   o  enable/disable events - enable or disable another event

  Namhyung Kim added updates to the tracing uprobes code.  Having the
  uprobes add support for fetch methods.

  The rest are various bug fixes with the new code, and minor ones for
  the old code"

* tag 'trace-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (38 commits)
  tracing: Fix buggered tee(2) on tracing_pipe
  tracing: Have trace buffer point back to trace_array
  ftrace: Fix synchronization location disabling and freeing ftrace_ops
  ftrace: Have function graph only trace based on global_ops filters
  ftrace: Synchronize setting function_trace_op with ftrace_trace_function
  tracing: Show available event triggers when no trigger is set
  tracing: Consolidate event trigger code
  tracing: Fix counter for traceon/off event triggers
  tracing: Remove double-underscore naming in syscall trigger invocations
  tracing/kprobes: Add trace event trigger invocations
  tracing/probes: Fix build break on !CONFIG_KPROBE_EVENT
  tracing/uprobes: Add @+file_offset fetch method
  uprobes: Allocate ->utask before handler_chain() for tracing handlers
  tracing/uprobes: Add support for full argument access methods
  tracing/uprobes: Fetch args before reserving a ring buffer
  tracing/uprobes: Pass 'is_return' to traceprobe_parse_probe_arg()
  tracing/probes: Implement 'memory' fetch method for uprobes
  tracing/probes: Add fetch{,_size} member into deref fetch method
  tracing/probes: Move 'symbol' fetch method to kprobes
  tracing/probes: Implement 'stack' fetch method for uprobes
  ...

3 files changed, 160 insertions, 10 deletions

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 31ea4b42836..f4233b195da 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -570,8 +570,6 @@ static inline int
 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
-loff_t ftrace_filter_lseek(struct file *file, loff_t offset, int whence);
-
 /* totally disable ftrace - can not re-enable after this */
 void ftrace_kill(void);
 
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 8c9b7a1c413..4e4cc28623a 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -1,3 +1,4 @@
+
 #ifndef _LINUX_FTRACE_EVENT_H
 #define _LINUX_FTRACE_EVENT_H
 
@@ -264,6 +265,8 @@ enum {
 	FTRACE_EVENT_FL_NO_SET_FILTER_BIT,
 	FTRACE_EVENT_FL_SOFT_MODE_BIT,
 	FTRACE_EVENT_FL_SOFT_DISABLED_BIT,
+	FTRACE_EVENT_FL_TRIGGER_MODE_BIT,
+	FTRACE_EVENT_FL_TRIGGER_COND_BIT,
 };
 
 /*
@@ -275,6 +278,8 @@ enum {
  *  SOFT_MODE     - The event is enabled/disabled by SOFT_DISABLED
  *  SOFT_DISABLED - When set, do not trace the event (even though its
  *                   tracepoint may be enabled)
+ *  TRIGGER_MODE  - When set, invoke the triggers associated with the event
+ *  TRIGGER_COND  - When set, one or more triggers has an associated filter
  */
 enum {
 	FTRACE_EVENT_FL_ENABLED		= (1 << FTRACE_EVENT_FL_ENABLED_BIT),
@@ -283,6 +288,8 @@ enum {
 	FTRACE_EVENT_FL_NO_SET_FILTER	= (1 << FTRACE_EVENT_FL_NO_SET_FILTER_BIT),
 	FTRACE_EVENT_FL_SOFT_MODE	= (1 << FTRACE_EVENT_FL_SOFT_MODE_BIT),
 	FTRACE_EVENT_FL_SOFT_DISABLED	= (1 << FTRACE_EVENT_FL_SOFT_DISABLED_BIT),
+	FTRACE_EVENT_FL_TRIGGER_MODE	= (1 << FTRACE_EVENT_FL_TRIGGER_MODE_BIT),
+	FTRACE_EVENT_FL_TRIGGER_COND	= (1 << FTRACE_EVENT_FL_TRIGGER_COND_BIT),
 };
 
 struct ftrace_event_file {
@@ -292,6 +299,7 @@ struct ftrace_event_file {
 	struct dentry			*dir;
 	struct trace_array		*tr;
 	struct ftrace_subsystem_dir	*system;
+	struct list_head		triggers;
 
 	/*
 	 * 32 bit flags:
@@ -299,6 +307,7 @@ struct ftrace_event_file {
 	 *   bit 1:		enabled cmd record
 	 *   bit 2:		enable/disable with the soft disable bit
 	 *   bit 3:		soft disabled
+	 *   bit 4:		trigger enabled
 	 *
 	 * Note: The bits must be set atomically to prevent races
 	 * from other writers. Reads of flags do not need to be in
@@ -310,6 +319,7 @@ struct ftrace_event_file {
 	 */
 	unsigned long		flags;
 	atomic_t		sm_ref;	/* soft-mode reference counter */
+	atomic_t		tm_ref;	/* trigger-mode reference counter */
 };
 
 #define __TRACE_EVENT_FLAGS(name, value)				\
@@ -337,6 +347,14 @@ struct ftrace_event_file {
 
 #define MAX_FILTER_STR_VAL	256	/* Should handle KSYM_SYMBOL_LEN */
 
+enum event_trigger_type {
+	ETT_NONE		= (0),
+	ETT_TRACE_ONOFF		= (1 << 0),
+	ETT_SNAPSHOT		= (1 << 1),
+	ETT_STACKTRACE		= (1 << 2),
+	ETT_EVENT_ENABLE	= (1 << 3),
+};
+
 extern void destroy_preds(struct ftrace_event_file *file);
 extern void destroy_call_preds(struct ftrace_event_call *call);
 extern int filter_match_preds(struct event_filter *filter, void *rec);
@@ -347,6 +365,127 @@ extern int filter_check_discard(struct ftrace_event_file *file, void *rec,
 extern int call_filter_check_discard(struct ftrace_event_call *call, void *rec,
 				     struct ring_buffer *buffer,
 				     struct ring_buffer_event *event);
+extern enum event_trigger_type event_triggers_call(struct ftrace_event_file *file,
+						   void *rec);
+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,
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 5c38606613d..1a8b28db377 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -418,6 +418,8 @@ static inline notrace int ftrace_get_offsets_##call(			\
  *	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; <-- defined in stage 1
  *	struct ring_buffer *buffer;
@@ -425,9 +427,12 @@ static inline notrace int ftrace_get_offsets_##call(			\
  *	int __data_size;
  *	int pc;
  *
- *	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT,
- *		     &ftrace_file->flags))
- *		return;
+ *	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();
@@ -445,8 +450,17 @@ static inline notrace int ftrace_get_offsets_##call(			\
  *	{ <assign>; }  <-- Here we assign the entries by the __field and
  *			   __array macros.
  *
- *	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(buffer, event, irq_flags, pc);
+ *
+ *	if (__tt)
+ *		event_triggers_post_call(ftrace_file, __tt);
  * }
  *
  * static struct trace_event ftrace_event_type_<call> = {
@@ -539,8 +553,7 @@ ftrace_raw_event_##call(void *__data, proto)				\
 	int __data_size;						\
 	int pc;								\
 									\
-	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT,			\
-		     &ftrace_file->flags))				\
+	if (ftrace_trigger_soft_disabled(ftrace_file))			\
 		return;							\
 									\
 	local_save_flags(irq_flags);					\
@@ -560,8 +573,8 @@ ftrace_raw_event_##call(void *__data, proto)				\
 									\
 	{ assign; }							\
 									\
-	if (!filter_check_discard(ftrace_file, entry, buffer, event))	\
-		trace_buffer_unlock_commit(buffer, event, irq_flags, pc); \
+	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