#ifndef _LINUX_FTRACE_EVENT_H
  #define _LINUX_FTRACE_EVENT_H
  
  #include <linux/ring_buffer.h>
  #include <linux/trace_seq.h>
  #include <linux/percpu.h>
  #include <linux/hardirq.h>
  #include <linux/perf_event.h>
  
  struct trace_array;
  struct trace_buffer;
  struct tracer;
  struct dentry;
  
  struct trace_print_flags {
  	unsigned long		mask;
  	const char		*name;
  };
  
  struct trace_print_flags_u64 {
  	unsigned long long	mask;
  	const char		*name;
  };
  
  const char *ftrace_print_flags_seq(struct trace_seq *p, const char *delim,
  				   unsigned long flags,
  				   const struct trace_print_flags *flag_array);
  
  const char *ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
  				     const struct trace_print_flags *symbol_array);
  
  #if BITS_PER_LONG == 32
  const char *ftrace_print_symbols_seq_u64(struct trace_seq *p,
  					 unsigned long long val,
  					 const struct trace_print_flags_u64
  								 *symbol_array);
  #endif
  
  const char *ftrace_print_hex_seq(struct trace_seq *p,
  				 const unsigned char *buf, int len);
  
  struct trace_iterator;
  struct trace_event;
  
  int ftrace_raw_output_prep(struct trace_iterator *iter,
  			   struct trace_event *event);
  
  /*
   * The trace entry - the most basic unit of tracing. This is what
   * is printed in the end as a single line in the trace output, such as:
   *
   *     bash-15816 [01]   235.197585: idle_cpu <- irq_enter
   */
  struct trace_entry {
  	unsigned short		type;
  	unsigned char		flags;
  	unsigned char		preempt_count;
  	int			pid;
  };
  
  #define FTRACE_MAX_EVENT						\
  	((1 << (sizeof(((struct trace_entry *)0)->type) * 8)) - 1)
  
  /*
   * Trace iterator - used by printout routines who present trace
   * results to users and which routines might sleep, etc:
   */
  struct trace_iterator {
  	struct trace_array	*tr;
  	struct tracer		*trace;
  	struct trace_buffer	*trace_buffer;
  	void			*private;
  	int			cpu_file;
  	struct mutex		mutex;
  	struct ring_buffer_iter	**buffer_iter;
  	unsigned long		iter_flags;
  
  	/* trace_seq for __print_flags() and __print_symbolic() etc. */
  	struct trace_seq	tmp_seq;
  
  	cpumask_var_t		started;
  
  	/* it's true when current open file is snapshot */
  	bool			snapshot;
  
  	/* The below is zeroed out in pipe_read */
  	struct trace_seq	seq;
  	struct trace_entry	*ent;
  	unsigned long		lost_events;
  	int			leftover;
  	int			ent_size;
  	int			cpu;
  	u64			ts;
  
  	loff_t			pos;
  	long			idx;
  
  	/* All new field here will be zeroed out in pipe_read */
  };
  
  enum trace_iter_flags {
  	TRACE_FILE_LAT_FMT	= 1,
  	TRACE_FILE_ANNOTATE	= 2,
  	TRACE_FILE_TIME_IN_NS	= 4,
  };
  
  
  typedef enum print_line_t (*trace_print_func)(struct trace_iterator *iter,
  				      int flags, struct trace_event *event);
  
  struct trace_event_functions {
  	trace_print_func	trace;
  	trace_print_func	raw;
  	trace_print_func	hex;
  	trace_print_func	binary;
  };
  
  struct trace_event {
  	struct hlist_node		node;
  	struct list_head		list;
  	int				type;
  	struct trace_event_functions	*funcs;
  };
  
  extern int register_ftrace_event(struct trace_event *event);
  extern int unregister_ftrace_event(struct trace_event *event);
  
  /* Return values for print_line callback */
  enum print_line_t {
  	TRACE_TYPE_PARTIAL_LINE	= 0,	/* Retry after flushing the seq */
  	TRACE_TYPE_HANDLED	= 1,
  	TRACE_TYPE_UNHANDLED	= 2,	/* Relay to other output functions */
  	TRACE_TYPE_NO_CONSUME	= 3	/* Handled but ask to not consume */
  };
  
  void tracing_generic_entry_update(struct trace_entry *entry,
  				  unsigned long flags,
  				  int pc);
  struct ftrace_event_file;
  
  struct ring_buffer_event *
  trace_event_buffer_lock_reserve(struct ring_buffer **current_buffer,
  				struct ftrace_event_file *ftrace_file,
  				int type, unsigned long len,
  				unsigned long flags, int pc);
  struct ring_buffer_event *
  trace_current_buffer_lock_reserve(struct ring_buffer **current_buffer,
  				  int type, unsigned long len,
  				  unsigned long flags, int pc);
  void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
  					struct ring_buffer_event *event,
  					unsigned long flags, int pc);
  void trace_buffer_unlock_commit(struct ring_buffer *buffer,
  				struct ring_buffer_event *event,
  				unsigned long flags, int pc);
  void trace_buffer_unlock_commit_regs(struct ring_buffer *buffer,
  				     struct ring_buffer_event *event,
  				     unsigned long flags, int pc,
  				     struct pt_regs *regs);
  void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
  					 struct ring_buffer_event *event);
  
  void tracing_record_cmdline(struct task_struct *tsk);
  
  struct event_filter;
  
  enum trace_reg {
  	TRACE_REG_REGISTER,
  	TRACE_REG_UNREGISTER,
  #ifdef CONFIG_PERF_EVENTS
  	TRACE_REG_PERF_REGISTER,
  	TRACE_REG_PERF_UNREGISTER,
  	TRACE_REG_PERF_OPEN,
  	TRACE_REG_PERF_CLOSE,
  	TRACE_REG_PERF_ADD,
  	TRACE_REG_PERF_DEL,
  #endif
  };
  
  struct ftrace_event_call;
  
  struct ftrace_event_class {
  	char			*system;
  	void			*probe;
  #ifdef CONFIG_PERF_EVENTS
  	void			*perf_probe;
  #endif
  	int			(*reg)(struct ftrace_event_call *event,
  				       enum trace_reg type, void *data);
  	int			(*define_fields)(struct ftrace_event_call *);
  	struct list_head	*(*get_fields)(struct ftrace_event_call *);
  	struct list_head	fields;
  	int			(*raw_init)(struct ftrace_event_call *);
  };
  
  extern int ftrace_event_reg(struct ftrace_event_call *event,
  			    enum trace_reg type, void *data);
  
  enum {
  	TRACE_EVENT_FL_FILTERED_BIT,
  	TRACE_EVENT_FL_CAP_ANY_BIT,
  	TRACE_EVENT_FL_NO_SET_FILTER_BIT,
  	TRACE_EVENT_FL_IGNORE_ENABLE_BIT,
  	TRACE_EVENT_FL_WAS_ENABLED_BIT,
  	TRACE_EVENT_FL_USE_CALL_FILTER_BIT,
  };
  
  /*
   * Event flags:
   *  FILTERED	  - The event has a filter attached
   *  CAP_ANY	  - Any user can enable for perf
   *  NO_SET_FILTER - Set when filter has error and is to be ignored
   *  IGNORE_ENABLE - For ftrace internal events, do not enable with debugfs file
   *  WAS_ENABLED   - Set and stays set when an event was ever enabled
   *                    (used for module unloading, if a module event is enabled,
   *                     it is best to clear the buffers that used it).
   *  USE_CALL_FILTER - For ftrace internal events, don't use file filter
   */
  enum {
  	TRACE_EVENT_FL_FILTERED		= (1 << TRACE_EVENT_FL_FILTERED_BIT),
  	TRACE_EVENT_FL_CAP_ANY		= (1 << TRACE_EVENT_FL_CAP_ANY_BIT),
  	TRACE_EVENT_FL_NO_SET_FILTER	= (1 << TRACE_EVENT_FL_NO_SET_FILTER_BIT),
  	TRACE_EVENT_FL_IGNORE_ENABLE	= (1 << TRACE_EVENT_FL_IGNORE_ENABLE_BIT),
  	TRACE_EVENT_FL_WAS_ENABLED	= (1 << TRACE_EVENT_FL_WAS_ENABLED_BIT),
  	TRACE_EVENT_FL_USE_CALL_FILTER	= (1 << TRACE_EVENT_FL_USE_CALL_FILTER_BIT),
  };
  
  struct ftrace_event_call {
  	struct list_head	list;
  	struct ftrace_event_class *class;
  	char			*name;
  	struct trace_event	event;
  	const char		*print_fmt;
  	struct event_filter	*filter;
  	struct list_head	*files;
  	void			*mod;
  	void			*data;
  	/*
  	 *   bit 0:		filter_active
  	 *   bit 1:		allow trace by non root (cap any)
  	 *   bit 2:		failed to apply filter
  	 *   bit 3:		ftrace internal event (do not enable)
  	 *   bit 4:		Event was enabled by module
  	 *   bit 5:		use call filter rather than file filter
  	 */
  	int			flags; /* static flags of different events */
  
  #ifdef CONFIG_PERF_EVENTS
  	int				perf_refcount;
  	struct hlist_head __percpu	*perf_events;
  
  	int	(*perf_perm)(struct ftrace_event_call *,
  			     struct perf_event *);
  #endif
  };
  
  struct trace_array;
  struct ftrace_subsystem_dir;
  
  enum {
  	FTRACE_EVENT_FL_ENABLED_BIT,
  	FTRACE_EVENT_FL_RECORDED_CMD_BIT,
  	FTRACE_EVENT_FL_FILTERED_BIT,
  	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,
  };
  
  /*
   * Ftrace event file flags:
   *  ENABLED	  - The event is enabled
   *  RECORDED_CMD  - The comms should be recorded at sched_switch
   *  FILTERED	  - The event has a filter attached
   *  NO_SET_FILTER - Set when filter has error and is to be ignored
   *  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),
  	FTRACE_EVENT_FL_RECORDED_CMD	= (1 << FTRACE_EVENT_FL_RECORDED_CMD_BIT),
  	FTRACE_EVENT_FL_FILTERED	= (1 << FTRACE_EVENT_FL_FILTERED_BIT),
  	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 {
  	struct list_head		list;
  	struct ftrace_event_call	*event_call;
  	struct event_filter		*filter;
  	struct dentry			*dir;
  	struct trace_array		*tr;
  	struct ftrace_subsystem_dir	*system;
  	struct list_head		triggers;
  
  	/*
  	 * 32 bit flags:
  	 *   bit 0:		enabled
  	 *   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
  	 * sync as they occur in critical sections. But the way flags
  	 * is currently used, these changes do not affect the code
  	 * except that when a change is made, it may have a slight
  	 * delay in propagating the changes to other CPUs due to
  	 * caching and such. Which is mostly OK ;-)
  	 */
  	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)				\
  	static int __init trace_init_flags_##name(void)			\
  	{								\
  		event_##name.flags = value;				\
  		return 0;						\
  	}								\
  	early_initcall(trace_init_flags_##name);
  
  #define __TRACE_EVENT_PERF_PERM(name, expr...)				\
  	static int perf_perm_##name(struct ftrace_event_call *tp_event, \
  				    struct perf_event *p_event)		\
  	{								\
  		return ({ expr; });					\
  	}								\
  	static int __init trace_init_perf_perm_##name(void)		\
  	{								\
  		event_##name.perf_perm = &perf_perm_##name;		\
  		return 0;						\
  	}								\
  	early_initcall(trace_init_perf_perm_##name);
  
  #define PERF_MAX_TRACE_SIZE	2048
  
  #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);
  
  extern int filter_check_discard(struct ftrace_event_file *file, void *rec,
  				struct ring_buffer *buffer,
  				struct ring_buffer_event *event);
  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,
  	FILTER_STATIC_STRING,
  	FILTER_DYN_STRING,
  	FILTER_PTR_STRING,
  	FILTER_TRACE_FN,
  };
  
  extern int trace_event_raw_init(struct ftrace_event_call *call);
  extern int trace_define_field(struct ftrace_event_call *call, const char *type,
  			      const char *name, int offset, int size,
  			      int is_signed, int filter_type);
  extern int trace_add_event_call(struct ftrace_event_call *call);
  extern int trace_remove_event_call(struct ftrace_event_call *call);
  
  #define is_signed_type(type)	(((type)(-1)) < (type)1)
  
  int trace_set_clr_event(const char *system, const char *event, int set);
  
  /*
   * The double __builtin_constant_p is because gcc will give us an error
   * if we try to allocate the static variable to fmt if it is not a
   * constant. Even with the outer if statement optimizing out.
   */
  #define event_trace_printk(ip, fmt, args...)				\
  do {									\
  	__trace_printk_check_format(fmt, ##args);			\
  	tracing_record_cmdline(current);				\
  	if (__builtin_constant_p(fmt)) {				\
  		static const char *trace_printk_fmt			\
  		  __attribute__((section("__trace_printk_fmt"))) =	\
  			__builtin_constant_p(fmt) ? fmt : NULL;		\
  									\
  		__trace_bprintk(ip, trace_printk_fmt, ##args);		\
  	} else								\
  		__trace_printk(ip, fmt, ##args);			\
  } while (0)
  
  /**
   * tracepoint_string - register constant persistent string to trace system
   * @str - a constant persistent string that will be referenced in tracepoints
   *
   * If constant strings are being used in tracepoints, it is faster and
   * more efficient to just save the pointer to the string and reference
   * that with a printf "%s" instead of saving the string in the ring buffer
   * and wasting space and time.
   *
   * The problem with the above approach is that userspace tools that read
   * the binary output of the trace buffers do not have access to the string.
   * Instead they just show the address of the string which is not very
   * useful to users.
   *
   * With tracepoint_string(), the string will be registered to the tracing
   * system and exported to userspace via the debugfs/tracing/printk_formats
   * file that maps the string address to the string text. This way userspace
   * tools that read the binary buffers have a way to map the pointers to
   * the ASCII strings they represent.
   *
   * The @str used must be a constant string and persistent as it would not
   * make sense to show a string that no longer exists. But it is still fine
   * to be used with modules, because when modules are unloaded, if they
   * had tracepoints, the ring buffers are cleared too. As long as the string
   * does not change during the life of the module, it is fine to use
   * tracepoint_string() within a module.
   */
  #define tracepoint_string(str)						\
  	({								\
  		static const char *___tp_str __tracepoint_string = str; \
  		___tp_str;						\
  	})
  #define __tracepoint_string	__attribute__((section("__tracepoint_str")))
  
  #ifdef CONFIG_PERF_EVENTS
  struct perf_event;
  
  DECLARE_PER_CPU(struct pt_regs, perf_trace_regs);
  
  extern int  perf_trace_init(struct perf_event *event);
  extern void perf_trace_destroy(struct perf_event *event);
  extern int  perf_trace_add(struct perf_event *event, int flags);
  extern void perf_trace_del(struct perf_event *event, int flags);
  extern int  ftrace_profile_set_filter(struct perf_event *event, int event_id,
  				     char *filter_str);
  extern void ftrace_profile_free_filter(struct perf_event *event);
  extern void *perf_trace_buf_prepare(int size, unsigned short type,
  				    struct pt_regs *regs, int *rctxp);
  
  static inline void
  perf_trace_buf_submit(void *raw_data, int size, int rctx, u64 addr,
  		       u64 count, struct pt_regs *regs, void *head,
  		       struct task_struct *task)
  {
  	perf_tp_event(addr, count, raw_data, size, regs, head, rctx, task);
  }
  #endif
  
  #endif /* _LINUX_FTRACE_EVENT_H */