xref: /openbmc/linux/kernel/trace/trace_export.c (revision 0c874100)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * trace_export.c - export basic ftrace utilities to user space
4  *
5  * Copyright (C) 2009 Steven Rostedt <srostedt@redhat.com>
6  */
7 #include <linux/stringify.h>
8 #include <linux/kallsyms.h>
9 #include <linux/seq_file.h>
10 #include <linux/uaccess.h>
11 #include <linux/ftrace.h>
12 #include <linux/module.h>
13 #include <linux/init.h>
14 
15 #include "trace_output.h"
16 
17 /* Stub function for events with triggers */
18 static int ftrace_event_register(struct trace_event_call *call,
19 				 enum trace_reg type, void *data)
20 {
21 	return 0;
22 }
23 
24 #undef TRACE_SYSTEM
25 #define TRACE_SYSTEM	ftrace
26 
27 /*
28  * The FTRACE_ENTRY_REG macro allows ftrace entry to define register
29  * function and thus become accesible via perf.
30  */
31 #undef FTRACE_ENTRY_REG
32 #define FTRACE_ENTRY_REG(name, struct_name, id, tstruct, print, \
33 			 filter, regfn) \
34 	FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \
35 		     filter)
36 
37 /* not needed for this file */
38 #undef __field_struct
39 #define __field_struct(type, item)
40 
41 #undef __field
42 #define __field(type, item)				type item;
43 
44 #undef __field_desc
45 #define __field_desc(type, container, item)		type item;
46 
47 #undef __array
48 #define __array(type, item, size)			type item[size];
49 
50 #undef __array_desc
51 #define __array_desc(type, container, item, size)	type item[size];
52 
53 #undef __dynamic_array
54 #define __dynamic_array(type, item)			type item[];
55 
56 #undef F_STRUCT
57 #define F_STRUCT(args...)				args
58 
59 #undef F_printk
60 #define F_printk(fmt, args...) fmt, args
61 
62 #undef FTRACE_ENTRY
63 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print, filter)	\
64 struct ____ftrace_##name {						\
65 	tstruct								\
66 };									\
67 static void __always_unused ____ftrace_check_##name(void)		\
68 {									\
69 	struct ____ftrace_##name *__entry = NULL;			\
70 									\
71 	/* force compile-time check on F_printk() */			\
72 	printk(print);							\
73 }
74 
75 #undef FTRACE_ENTRY_DUP
76 #define FTRACE_ENTRY_DUP(name, struct_name, id, tstruct, print, filter)	\
77 	FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \
78 		     filter)
79 
80 #include "trace_entries.h"
81 
82 #undef __field
83 #define __field(type, item)						\
84 	ret = trace_define_field(event_call, #type, #item,		\
85 				 offsetof(typeof(field), item),		\
86 				 sizeof(field.item),			\
87 				 is_signed_type(type), filter_type);	\
88 	if (ret)							\
89 		return ret;
90 
91 #undef __field_desc
92 #define __field_desc(type, container, item)	\
93 	ret = trace_define_field(event_call, #type, #item,		\
94 				 offsetof(typeof(field),		\
95 					  container.item),		\
96 				 sizeof(field.container.item),		\
97 				 is_signed_type(type), filter_type);	\
98 	if (ret)							\
99 		return ret;
100 
101 #undef __array
102 #define __array(type, item, len)					\
103 	do {								\
104 		char *type_str = #type"["__stringify(len)"]";		\
105 		BUILD_BUG_ON(len > MAX_FILTER_STR_VAL);			\
106 		ret = trace_define_field(event_call, type_str, #item,	\
107 				 offsetof(typeof(field), item),		\
108 				 sizeof(field.item),			\
109 				 is_signed_type(type), filter_type);	\
110 		if (ret)						\
111 			return ret;					\
112 	} while (0);
113 
114 #undef __array_desc
115 #define __array_desc(type, container, item, len)			\
116 	BUILD_BUG_ON(len > MAX_FILTER_STR_VAL);				\
117 	ret = trace_define_field(event_call, #type "[" #len "]", #item,	\
118 				 offsetof(typeof(field),		\
119 					  container.item),		\
120 				 sizeof(field.container.item),		\
121 				 is_signed_type(type), filter_type);	\
122 	if (ret)							\
123 		return ret;
124 
125 #undef __dynamic_array
126 #define __dynamic_array(type, item)					\
127 	ret = trace_define_field(event_call, #type "[]", #item,  \
128 				 offsetof(typeof(field), item),		\
129 				 0, is_signed_type(type), filter_type);\
130 	if (ret)							\
131 		return ret;
132 
133 #undef FTRACE_ENTRY
134 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print, filter)	\
135 static int __init							\
136 ftrace_define_fields_##name(struct trace_event_call *event_call)	\
137 {									\
138 	struct struct_name field;					\
139 	int ret;							\
140 	int filter_type = filter;					\
141 									\
142 	tstruct;							\
143 									\
144 	return ret;							\
145 }
146 
147 #include "trace_entries.h"
148 
149 #undef __entry
150 #define __entry REC
151 
152 #undef __field
153 #define __field(type, item)
154 
155 #undef __field_desc
156 #define __field_desc(type, container, item)
157 
158 #undef __array
159 #define __array(type, item, len)
160 
161 #undef __array_desc
162 #define __array_desc(type, container, item, len)
163 
164 #undef __dynamic_array
165 #define __dynamic_array(type, item)
166 
167 #undef F_printk
168 #define F_printk(fmt, args...) __stringify(fmt) ", "  __stringify(args)
169 
170 #undef FTRACE_ENTRY_REG
171 #define FTRACE_ENTRY_REG(call, struct_name, etype, tstruct, print, filter,\
172 			 regfn)						\
173 									\
174 struct trace_event_class __refdata event_class_ftrace_##call = {	\
175 	.system			= __stringify(TRACE_SYSTEM),		\
176 	.define_fields		= ftrace_define_fields_##call,		\
177 	.fields			= LIST_HEAD_INIT(event_class_ftrace_##call.fields),\
178 	.reg			= regfn,				\
179 };									\
180 									\
181 struct trace_event_call __used event_##call = {				\
182 	.class			= &event_class_ftrace_##call,		\
183 	{								\
184 		.name			= #call,			\
185 	},								\
186 	.event.type		= etype,				\
187 	.print_fmt		= print,				\
188 	.flags			= TRACE_EVENT_FL_IGNORE_ENABLE,		\
189 };									\
190 struct trace_event_call __used						\
191 __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call;
192 
193 #undef FTRACE_ENTRY
194 #define FTRACE_ENTRY(call, struct_name, etype, tstruct, print, filter)	\
195 	FTRACE_ENTRY_REG(call, struct_name, etype,			\
196 			 PARAMS(tstruct), PARAMS(print), filter, NULL)
197 
198 bool ftrace_event_is_function(struct trace_event_call *call)
199 {
200 	return call == &event_function;
201 }
202 
203 #include "trace_entries.h"
204