+
#ifndef _LINUX_KERNEL_TRACE_H
#define _LINUX_KERNEL_TRACE_H
int register_tracer(struct tracer *type);
int is_tracing_stopped(void);
+loff_t tracing_lseek(struct file *file, loff_t offset, int whence);
+
extern cpumask_var_t __read_mostly tracing_buffer_mask;
#define for_each_tracing_cpu(cpu) \
extern void print_subsystem_event_filter(struct event_subsystem *system,
struct trace_seq *s);
extern int filter_assign_type(const char *type);
+extern int create_event_filter(struct ftrace_event_call *call,
+ char *filter_str, bool set_str,
+ struct event_filter **filterp);
+extern void free_event_filter(struct event_filter *filter);
struct ftrace_event_field *
trace_find_event_field(struct ftrace_event_call *call, char *name);
extern int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr);
extern int event_trace_del_tracer(struct trace_array *tr);
+extern struct ftrace_event_file *find_event_file(struct trace_array *tr,
+ const char *system,
+ const char *event);
+
+static inline void *event_file_data(struct file *filp)
+{
+ return ACCESS_ONCE(file_inode(filp)->i_private);
+}
+
extern struct mutex event_mutex;
extern struct list_head ftrace_events;
+extern const struct file_operations event_trigger_fops;
+
+extern int register_trigger_cmds(void);
+extern void clear_event_triggers(struct trace_array *tr);
+
+struct event_trigger_data {
+ unsigned long count;
+ int ref;
+ struct event_trigger_ops *ops;
+ struct event_command *cmd_ops;
+ struct event_filter __rcu *filter;
+ char *filter_str;
+ void *private_data;
+ struct list_head list;
+};
+
+/**
+ * struct event_trigger_ops - callbacks for trace event triggers
+ *
+ * The methods in this structure provide per-event trigger hooks for
+ * various trigger operations.
+ *
+ * All the methods below, except for @init() and @free(), must be
+ * implemented.
+ *
+ * @func: The trigger 'probe' function called when the triggering
+ * event occurs. The data passed into this callback is the data
+ * that was supplied to the event_command @reg() function that
+ * registered the trigger (see struct event_command).
+ *
+ * @init: An optional initialization function called for the trigger
+ * when the trigger is registered (via the event_command reg()
+ * function). This can be used to perform per-trigger
+ * initialization such as incrementing a per-trigger reference
+ * count, for instance. This is usually implemented by the
+ * generic utility function @event_trigger_init() (see
+ * trace_event_triggers.c).
+ *
+ * @free: An optional de-initialization function called for the
+ * trigger when the trigger is unregistered (via the
+ * event_command @reg() function). This can be used to perform
+ * per-trigger de-initialization such as decrementing a
+ * per-trigger reference count and freeing corresponding trigger
+ * data, for instance. This is usually implemented by the
+ * generic utility function @event_trigger_free() (see
+ * trace_event_triggers.c).
+ *
+ * @print: The callback function invoked to have the trigger print
+ * itself. This is usually implemented by a wrapper function
+ * that calls the generic utility function @event_trigger_print()
+ * (see trace_event_triggers.c).
+ */
+struct event_trigger_ops {
+ void (*func)(struct event_trigger_data *data);
+ int (*init)(struct event_trigger_ops *ops,
+ struct event_trigger_data *data);
+ void (*free)(struct event_trigger_ops *ops,
+ struct event_trigger_data *data);
+ int (*print)(struct seq_file *m,
+ struct event_trigger_ops *ops,
+ struct event_trigger_data *data);
+};
+
+/**
+ * struct event_command - callbacks and data members for event commands
+ *
+ * Event commands are invoked by users by writing the command name
+ * into the 'trigger' file associated with a trace event. The
+ * parameters associated with a specific invocation of an event
+ * command are used to create an event trigger instance, which is
+ * added to the list of trigger instances associated with that trace
+ * event. When the event is hit, the set of triggers associated with
+ * that event is invoked.
+ *
+ * The data members in this structure provide per-event command data
+ * for various event commands.
+ *
+ * All the data members below, except for @post_trigger, must be set
+ * for each event command.
+ *
+ * @name: The unique name that identifies the event command. This is
+ * the name used when setting triggers via trigger files.
+ *
+ * @trigger_type: A unique id that identifies the event command
+ * 'type'. This value has two purposes, the first to ensure that
+ * only one trigger of the same type can be set at a given time
+ * for a particular event e.g. it doesn't make sense to have both
+ * a traceon and traceoff trigger attached to a single event at
+ * the same time, so traceon and traceoff have the same type
+ * though they have different names. The @trigger_type value is
+ * also used as a bit value for deferring the actual trigger
+ * action until after the current event is finished. Some
+ * commands need to do this if they themselves log to the trace
+ * buffer (see the @post_trigger() member below). @trigger_type
+ * values are defined by adding new values to the trigger_type
+ * enum in include/linux/ftrace_event.h.
+ *
+ * @post_trigger: A flag that says whether or not this command needs
+ * to have its action delayed until after the current event has
+ * been closed. Some triggers need to avoid being invoked while
+ * an event is currently in the process of being logged, since
+ * the trigger may itself log data into the trace buffer. Thus
+ * we make sure the current event is committed before invoking
+ * those triggers. To do that, the trigger invocation is split
+ * in two - the first part checks the filter using the current
+ * trace record; if a command has the @post_trigger flag set, it
+ * sets a bit for itself in the return value, otherwise it
+ * directly invokes the trigger. Once all commands have been
+ * either invoked or set their return flag, the current record is
+ * either committed or discarded. At that point, if any commands
+ * have deferred their triggers, those commands are finally
+ * invoked following the close of the current event. In other
+ * words, if the event_trigger_ops @func() probe implementation
+ * itself logs to the trace buffer, this flag should be set,
+ * otherwise it can be left unspecified.
+ *
+ * All the methods below, except for @set_filter(), must be
+ * implemented.
+ *
+ * @func: The callback function responsible for parsing and
+ * registering the trigger written to the 'trigger' file by the
+ * user. It allocates the trigger instance and registers it with
+ * the appropriate trace event. It makes use of the other
+ * event_command callback functions to orchestrate this, and is
+ * usually implemented by the generic utility function
+ * @event_trigger_callback() (see trace_event_triggers.c).
+ *
+ * @reg: Adds the trigger to the list of triggers associated with the
+ * event, and enables the event trigger itself, after
+ * initializing it (via the event_trigger_ops @init() function).
+ * This is also where commands can use the @trigger_type value to
+ * make the decision as to whether or not multiple instances of
+ * the trigger should be allowed. This is usually implemented by
+ * the generic utility function @register_trigger() (see
+ * trace_event_triggers.c).
+ *
+ * @unreg: Removes the trigger from the list of triggers associated
+ * with the event, and disables the event trigger itself, after
+ * initializing it (via the event_trigger_ops @free() function).
+ * This is usually implemented by the generic utility function
+ * @unregister_trigger() (see trace_event_triggers.c).
+ *
+ * @set_filter: An optional function called to parse and set a filter
+ * for the trigger. If no @set_filter() method is set for the
+ * event command, filters set by the user for the command will be
+ * ignored. This is usually implemented by the generic utility
+ * function @set_trigger_filter() (see trace_event_triggers.c).
+ *
+ * @get_trigger_ops: The callback function invoked to retrieve the
+ * event_trigger_ops implementation associated with the command.
+ */
+struct event_command {
+ struct list_head list;
+ char *name;
+ enum event_trigger_type trigger_type;
+ bool post_trigger;
+ int (*func)(struct event_command *cmd_ops,
+ struct ftrace_event_file *file,
+ char *glob, char *cmd, char *params);
+ int (*reg)(char *glob,
+ struct event_trigger_ops *ops,
+ struct event_trigger_data *data,
+ struct ftrace_event_file *file);
+ void (*unreg)(char *glob,
+ struct event_trigger_ops *ops,
+ struct event_trigger_data *data,
+ struct ftrace_event_file *file);
+ int (*set_filter)(char *filter_str,
+ struct event_trigger_data *data,
+ struct ftrace_event_file *file);
+ struct event_trigger_ops *(*get_trigger_ops)(char *cmd, char *param);
+};
+
+extern int trace_event_enable_disable(struct ftrace_event_file *file,
+ int enable, int soft_disable);
+extern int tracing_alloc_snapshot(void);
+
extern const char *__start___trace_bprintk_fmt[];
extern const char *__stop___trace_bprintk_fmt[];
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