Lines Matching refs:callback

26   The ability to add a callback to almost any function within the
27   kernel comes with risks. A callback can be called from any context
30   This requires extra care to what can be done inside a callback. A callback
40 To register a function callback, a ftrace_ops is required. This structure
41 is used to tell ftrace what function should be called as the callback
42 as well as what protections the callback will perform and not require
70 The registered callback will start being called some time after the
73 of services. The callback itself will have to handle any synchronization if it
76 The unregister_ftrace_function() will guarantee that the callback is
82 The callback function
85 The prototype of the callback function is as follows (as of v4.14):
101 	This is a pointer to ftrace_ops that was used to register the callback.
102 	This can be used to pass data to the callback via the private pointer.
120 	If the callback requires reading or modifying the pt_regs
121 	passed to the callback, then it must set this flag. Registering
123 	support passing of pt_regs to the callback will fail.
128 	will not fail with this flag set. But the callback must check if
132 	By default, a wrapper is added around the callback to
134 	if a function that is called as a result of the callback's execution
135 	is also traced, ftrace will prevent the callback from being called
136 	again. But this wrapper adds some overhead, and if the callback is
143 	It is OK if another callback traces a function that is called by a
144 	callback that is marked recursion safe. Recursion safe callbacks
145 	must never trace any function that are called by the callback
148 	If this flag is set, it is possible that the callback will also
153 	Requires FTRACE_OPS_FL_SAVE_REGS set. If the callback is to "hijack"
163 	If this is set, then the callback will only be called by functions
164 	where RCU is "watching". This is required if the callback function
170 	a callback may be executed and RCU synchronization will not protect
175         writing 0 to the proc sysctl ftrace_enabled. Equally, a callback with
185 If a callback is only to be called from specific functions, a filter must be
241 list that will prevent those functions from calling the callback.
243 two lists are non-empty and contain the same functions, the callback will not
268 functions should call the callback, it is best to set the filters before
269 registering the callback. But the changes may also happen after the callback
274 the ftrace_set_filter() call. At no time will all functions call the callback.
301 the callback, between the time of the reset, and the time of the