xref: /openbmc/linux/kernel/trace/trace_export.c (revision f9834f18)
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, regfn) \
33 	FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print))
34 
35 /* not needed for this file */
36 #undef __field_struct
37 #define __field_struct(type, item)
38 
39 #undef __field
40 #define __field(type, item)				type item;
41 
42 #undef __field_fn
43 #define __field_fn(type, item)				type item;
44 
45 #undef __field_desc
46 #define __field_desc(type, container, item)		type item;
47 
48 #undef __array
49 #define __array(type, item, size)			type item[size];
50 
51 #undef __array_desc
52 #define __array_desc(type, container, item, size)	type item[size];
53 
54 #undef __dynamic_array
55 #define __dynamic_array(type, item)			type item[];
56 
57 #undef F_STRUCT
58 #define F_STRUCT(args...)				args
59 
60 #undef F_printk
61 #define F_printk(fmt, args...) fmt, args
62 
63 #undef FTRACE_ENTRY
64 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print)		\
65 struct ____ftrace_##name {						\
66 	tstruct								\
67 };									\
68 static void __always_unused ____ftrace_check_##name(void)		\
69 {									\
70 	struct ____ftrace_##name *__entry = NULL;			\
71 									\
72 	/* force compile-time check on F_printk() */			\
73 	printk(print);							\
74 }
75 
76 #undef FTRACE_ENTRY_DUP
77 #define FTRACE_ENTRY_DUP(name, struct_name, id, tstruct, print)		\
78 	FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print))
79 
80 #include "trace_entries.h"
81 
82 #undef __field_ext
83 #define __field_ext(_type, _item, _filter_type) {			\
84 	.type = #_type, .name = #_item,					\
85 	.size = sizeof(_type), .align = __alignof__(_type),		\
86 	is_signed_type(_type), .filter_type = _filter_type },
87 
88 #undef __field
89 #define __field(_type, _item) __field_ext(_type, _item, FILTER_OTHER)
90 
91 #undef __field_fn
92 #define __field_fn(_type, _item) __field_ext(_type, _item, FILTER_TRACE_FN)
93 
94 #undef __field_desc
95 #define __field_desc(_type, _container, _item) __field_ext(_type, _item, FILTER_OTHER)
96 
97 #undef __array
98 #define __array(_type, _item, _len) {					\
99 	.type = #_type"["__stringify(_len)"]", .name = #_item,		\
100 	.size = sizeof(_type[_len]), .align = __alignof__(_type),	\
101 	is_signed_type(_type), .filter_type = FILTER_OTHER },
102 
103 #undef __array_desc
104 #define __array_desc(_type, _container, _item, _len) __array(_type, _item, _len)
105 
106 #undef __dynamic_array
107 #define __dynamic_array(_type, _item) {					\
108 	.type = #_type "[]", .name = #_item,				\
109 	.size = 0, .align = __alignof__(_type),				\
110 	is_signed_type(_type), .filter_type = FILTER_OTHER },
111 
112 #undef FTRACE_ENTRY
113 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print)		\
114 static struct trace_event_fields ftrace_event_fields_##name[] = {	\
115 	tstruct								\
116 	{} };
117 
118 #include "trace_entries.h"
119 
120 #undef __entry
121 #define __entry REC
122 
123 #undef __field
124 #define __field(type, item)
125 
126 #undef __field_fn
127 #define __field_fn(type, item)
128 
129 #undef __field_desc
130 #define __field_desc(type, container, item)
131 
132 #undef __array
133 #define __array(type, item, len)
134 
135 #undef __array_desc
136 #define __array_desc(type, container, item, len)
137 
138 #undef __dynamic_array
139 #define __dynamic_array(type, item)
140 
141 #undef F_printk
142 #define F_printk(fmt, args...) __stringify(fmt) ", "  __stringify(args)
143 
144 #undef FTRACE_ENTRY_REG
145 #define FTRACE_ENTRY_REG(call, struct_name, etype, tstruct, print, regfn) \
146 static struct trace_event_class __refdata event_class_ftrace_##call = {	\
147 	.system			= __stringify(TRACE_SYSTEM),		\
148 	.fields_array		= ftrace_event_fields_##call,		\
149 	.fields			= LIST_HEAD_INIT(event_class_ftrace_##call.fields),\
150 	.reg			= regfn,				\
151 };									\
152 									\
153 struct trace_event_call __used event_##call = {				\
154 	.class			= &event_class_ftrace_##call,		\
155 	{								\
156 		.name			= #call,			\
157 	},								\
158 	.event.type		= etype,				\
159 	.print_fmt		= print,				\
160 	.flags			= TRACE_EVENT_FL_IGNORE_ENABLE,		\
161 };									\
162 static struct trace_event_call __used						\
163 __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call;
164 
165 #undef FTRACE_ENTRY
166 #define FTRACE_ENTRY(call, struct_name, etype, tstruct, print)		\
167 	FTRACE_ENTRY_REG(call, struct_name, etype,			\
168 			 PARAMS(tstruct), PARAMS(print), NULL)
169 
170 bool ftrace_event_is_function(struct trace_event_call *call)
171 {
172 	return call == &event_function;
173 }
174 
175 #include "trace_entries.h"
176