Commit 4d4c9cc8 authored by Steven Rostedt's avatar Steven Rostedt
Browse files

tracing: Add __field_struct macro for TRACE_EVENT() 



Currently the __field() macro in TRACE_EVENT is only good for primitive
values, such as integers and pointers, but it fails on complex data types
such as structures or unions. This is because the __field() macro
determines if the variable is signed or not with the test of:

  (((type)(-1)) < (type)1)

Unfortunately, that fails when type is a structure.

Since trace events should support structures as fields a new macro
is created for such a case called __field_struct() which acts exactly
the same as __field() does but it does not do the signed type check
and just uses a constant false for that answer.

Cc: Tony Luck <tony.luck@gmail.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent ea73c79e

include/trace/ftrace.h

+33 −0
Original line number Diff line number Diff line
@@ -44,6 +44,12 @@ 
#undef __field_ext

#define __field_ext(type, item, filter_type)	type	item;



#undef __field_struct

#define __field_struct(type, item)	type	item;



#undef __field_struct_ext

#define __field_struct_ext(type, item, filter_type)	type	item;



#undef __array

#define __array(type, item, len)	type	item[len];
@@ -122,6 +128,12 @@ 
#undef __field_ext

#define __field_ext(type, item, filter_type)



#undef __field_struct

#define __field_struct(type, item)



#undef __field_struct_ext

#define __field_struct_ext(type, item, filter_type)



#undef __array

#define __array(type, item, len)
@@ -315,9 +327,21 @@ static struct trace_event_functions ftrace_event_type_funcs_##call = { \ 
	if (ret)							\

		return ret;



#undef __field_struct_ext

#define __field_struct_ext(type, item, filter_type)			\

	ret = trace_define_field(event_call, #type, #item,		\

				 offsetof(typeof(field), item),		\

				 sizeof(field.item),			\

				 0, filter_type);			\

	if (ret)							\

		return ret;



#undef __field

#define __field(type, item)	__field_ext(type, item, FILTER_OTHER)



#undef __field_struct

#define __field_struct(type, item) __field_struct_ext(type, item, FILTER_OTHER)



#undef __array

#define __array(type, item, len)					\

	do {								\
@@ -379,6 +403,12 @@ ftrace_define_fields_##call(struct ftrace_event_call *event_call) \ 
#undef __field_ext

#define __field_ext(type, item, filter_type)



#undef __field_struct

#define __field_struct(type, item)



#undef __field_struct_ext

#define __field_struct_ext(type, item, filter_type)



#undef __array

#define __array(type, item, len)
@@ -550,6 +580,9 @@ static inline notrace int ftrace_get_offsets_##call( \ 
#undef __field

#define __field(type, item)



#undef __field_struct

#define __field_struct(type, item)



#undef __array

#define __array(type, item, len)

samples/trace_events/trace-events-sample.h

+2 −1
Original line number Diff line number Diff line
@@ -56,7 +56,8 @@ 
 * struct:  This defines the way the data will be stored in the ring buffer.

 *    There are currently two types of elements. __field and __array.

 *    a __field is broken up into (type, name). Where type can be any

 *    type but an array.

 *    primitive type (integer, long or pointer). __field_struct() can

 *    be any static complex data value (struct, union, but not an array).

 *    For an array. there are three fields. (type, name, size). The

 *    type of elements in the array, the name of the field and the size

 *    of the array.

CRA Git | Maintained and supported by SUSTech CRA and CCSE