ssb: remove the ssb DMA API
[linux-2.6.git] / include / linux / tracepoint.h
1 #ifndef _LINUX_TRACEPOINT_H
2 #define _LINUX_TRACEPOINT_H
3
4 /*
5  * Kernel Tracepoint API.
6  *
7  * See Documentation/trace/tracepoints.txt.
8  *
9  * (C) Copyright 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
10  *
11  * Heavily inspired from the Linux Kernel Markers.
12  *
13  * This file is released under the GPLv2.
14  * See the file COPYING for more details.
15  */
16
17 #include <linux/types.h>
18 #include <linux/rcupdate.h>
19
20 struct module;
21 struct tracepoint;
22
23 struct tracepoint {
24         const char *name;               /* Tracepoint name */
25         int state;                      /* State. */
26         void (*regfunc)(void);
27         void (*unregfunc)(void);
28         void **funcs;
29 } __attribute__((aligned(32)));         /*
30                                          * Aligned on 32 bytes because it is
31                                          * globally visible and gcc happily
32                                          * align these on the structure size.
33                                          * Keep in sync with vmlinux.lds.h.
34                                          */
35
36 /*
37  * Connect a probe to a tracepoint.
38  * Internal API, should not be used directly.
39  */
40 extern int tracepoint_probe_register(const char *name, void *probe);
41
42 /*
43  * Disconnect a probe from a tracepoint.
44  * Internal API, should not be used directly.
45  */
46 extern int tracepoint_probe_unregister(const char *name, void *probe);
47
48 extern int tracepoint_probe_register_noupdate(const char *name, void *probe);
49 extern int tracepoint_probe_unregister_noupdate(const char *name, void *probe);
50 extern void tracepoint_probe_update_all(void);
51
52 struct tracepoint_iter {
53         struct module *module;
54         struct tracepoint *tracepoint;
55 };
56
57 extern void tracepoint_iter_start(struct tracepoint_iter *iter);
58 extern void tracepoint_iter_next(struct tracepoint_iter *iter);
59 extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
60 extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
61 extern int tracepoint_get_iter_range(struct tracepoint **tracepoint,
62         struct tracepoint *begin, struct tracepoint *end);
63
64 /*
65  * tracepoint_synchronize_unregister must be called between the last tracepoint
66  * probe unregistration and the end of module exit to make sure there is no
67  * caller executing a probe when it is freed.
68  */
69 static inline void tracepoint_synchronize_unregister(void)
70 {
71         synchronize_sched();
72 }
73
74 #define PARAMS(args...) args
75
76 #ifdef CONFIG_TRACEPOINTS
77 extern void tracepoint_update_probe_range(struct tracepoint *begin,
78         struct tracepoint *end);
79 #else
80 static inline void tracepoint_update_probe_range(struct tracepoint *begin,
81         struct tracepoint *end)
82 { }
83 #endif /* CONFIG_TRACEPOINTS */
84
85 #endif /* _LINUX_TRACEPOINT_H */
86
87 /*
88  * Note: we keep the TRACE_EVENT and DECLARE_TRACE outside the include
89  *  file ifdef protection.
90  *  This is due to the way trace events work. If a file includes two
91  *  trace event headers under one "CREATE_TRACE_POINTS" the first include
92  *  will override the TRACE_EVENT and break the second include.
93  */
94
95 #ifndef DECLARE_TRACE
96
97 #define TP_PROTO(args...)       args
98 #define TP_ARGS(args...)        args
99
100 #ifdef CONFIG_TRACEPOINTS
101
102 /*
103  * it_func[0] is never NULL because there is at least one element in the array
104  * when the array itself is non NULL.
105  */
106 #define __DO_TRACE(tp, proto, args)                                     \
107         do {                                                            \
108                 void **it_func;                                         \
109                                                                         \
110                 rcu_read_lock_sched_notrace();                          \
111                 it_func = rcu_dereference_sched((tp)->funcs);           \
112                 if (it_func) {                                          \
113                         do {                                            \
114                                 ((void(*)(proto))(*it_func))(args);     \
115                         } while (*(++it_func));                         \
116                 }                                                       \
117                 rcu_read_unlock_sched_notrace();                        \
118         } while (0)
119
120 /*
121  * Make sure the alignment of the structure in the __tracepoints section will
122  * not add unwanted padding between the beginning of the section and the
123  * structure. Force alignment to the same alignment as the section start.
124  */
125 #define DECLARE_TRACE(name, proto, args)                                \
126         extern struct tracepoint __tracepoint_##name;                   \
127         static inline void trace_##name(proto)                          \
128         {                                                               \
129                 if (unlikely(__tracepoint_##name.state))                \
130                         __DO_TRACE(&__tracepoint_##name,                \
131                                 TP_PROTO(proto), TP_ARGS(args));        \
132         }                                                               \
133         static inline int register_trace_##name(void (*probe)(proto))   \
134         {                                                               \
135                 return tracepoint_probe_register(#name, (void *)probe); \
136         }                                                               \
137         static inline int unregister_trace_##name(void (*probe)(proto)) \
138         {                                                               \
139                 return tracepoint_probe_unregister(#name, (void *)probe);\
140         }
141
142
143 #define DEFINE_TRACE_FN(name, reg, unreg)                               \
144         static const char __tpstrtab_##name[]                           \
145         __attribute__((section("__tracepoints_strings"))) = #name;      \
146         struct tracepoint __tracepoint_##name                           \
147         __attribute__((section("__tracepoints"), aligned(32))) =        \
148                 { __tpstrtab_##name, 0, reg, unreg, NULL }
149
150 #define DEFINE_TRACE(name)                                              \
151         DEFINE_TRACE_FN(name, NULL, NULL);
152
153 #define EXPORT_TRACEPOINT_SYMBOL_GPL(name)                              \
154         EXPORT_SYMBOL_GPL(__tracepoint_##name)
155 #define EXPORT_TRACEPOINT_SYMBOL(name)                                  \
156         EXPORT_SYMBOL(__tracepoint_##name)
157
158 #else /* !CONFIG_TRACEPOINTS */
159 #define DECLARE_TRACE(name, proto, args)                                \
160         static inline void _do_trace_##name(struct tracepoint *tp, proto) \
161         { }                                                             \
162         static inline void trace_##name(proto)                          \
163         { }                                                             \
164         static inline int register_trace_##name(void (*probe)(proto))   \
165         {                                                               \
166                 return -ENOSYS;                                         \
167         }                                                               \
168         static inline int unregister_trace_##name(void (*probe)(proto)) \
169         {                                                               \
170                 return -ENOSYS;                                         \
171         }
172
173 #define DEFINE_TRACE_FN(name, reg, unreg)
174 #define DEFINE_TRACE(name)
175 #define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
176 #define EXPORT_TRACEPOINT_SYMBOL(name)
177
178 #endif /* CONFIG_TRACEPOINTS */
179 #endif /* DECLARE_TRACE */
180
181 #ifndef TRACE_EVENT
182 /*
183  * For use with the TRACE_EVENT macro:
184  *
185  * We define a tracepoint, its arguments, its printk format
186  * and its 'fast binay record' layout.
187  *
188  * Firstly, name your tracepoint via TRACE_EVENT(name : the
189  * 'subsystem_event' notation is fine.
190  *
191  * Think about this whole construct as the
192  * 'trace_sched_switch() function' from now on.
193  *
194  *
195  *  TRACE_EVENT(sched_switch,
196  *
197  *      *
198  *      * A function has a regular function arguments
199  *      * prototype, declare it via TP_PROTO():
200  *      *
201  *
202  *      TP_PROTO(struct rq *rq, struct task_struct *prev,
203  *               struct task_struct *next),
204  *
205  *      *
206  *      * Define the call signature of the 'function'.
207  *      * (Design sidenote: we use this instead of a
208  *      *  TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
209  *      *
210  *
211  *      TP_ARGS(rq, prev, next),
212  *
213  *      *
214  *      * Fast binary tracing: define the trace record via
215  *      * TP_STRUCT__entry(). You can think about it like a
216  *      * regular C structure local variable definition.
217  *      *
218  *      * This is how the trace record is structured and will
219  *      * be saved into the ring buffer. These are the fields
220  *      * that will be exposed to user-space in
221  *      * /sys/kernel/debug/tracing/events/<*>/format.
222  *      *
223  *      * The declared 'local variable' is called '__entry'
224  *      *
225  *      * __field(pid_t, prev_prid) is equivalent to a standard declariton:
226  *      *
227  *      *       pid_t   prev_pid;
228  *      *
229  *      * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to:
230  *      *
231  *      *       char    prev_comm[TASK_COMM_LEN];
232  *      *
233  *
234  *      TP_STRUCT__entry(
235  *              __array(        char,   prev_comm,      TASK_COMM_LEN   )
236  *              __field(        pid_t,  prev_pid                        )
237  *              __field(        int,    prev_prio                       )
238  *              __array(        char,   next_comm,      TASK_COMM_LEN   )
239  *              __field(        pid_t,  next_pid                        )
240  *              __field(        int,    next_prio                       )
241  *      ),
242  *
243  *      *
244  *      * Assign the entry into the trace record, by embedding
245  *      * a full C statement block into TP_fast_assign(). You
246  *      * can refer to the trace record as '__entry' -
247  *      * otherwise you can put arbitrary C code in here.
248  *      *
249  *      * Note: this C code will execute every time a trace event
250  *      * happens, on an active tracepoint.
251  *      *
252  *
253  *      TP_fast_assign(
254  *              memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
255  *              __entry->prev_pid       = prev->pid;
256  *              __entry->prev_prio      = prev->prio;
257  *              memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
258  *              __entry->next_pid       = next->pid;
259  *              __entry->next_prio      = next->prio;
260  *      )
261  *
262  *      *
263  *      * Formatted output of a trace record via TP_printk().
264  *      * This is how the tracepoint will appear under ftrace
265  *      * plugins that make use of this tracepoint.
266  *      *
267  *      * (raw-binary tracing wont actually perform this step.)
268  *      *
269  *
270  *      TP_printk("task %s:%d [%d] ==> %s:%d [%d]",
271  *              __entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
272  *              __entry->next_comm, __entry->next_pid, __entry->next_prio),
273  *
274  * );
275  *
276  * This macro construct is thus used for the regular printk format
277  * tracing setup, it is used to construct a function pointer based
278  * tracepoint callback (this is used by programmatic plugins and
279  * can also by used by generic instrumentation like SystemTap), and
280  * it is also used to expose a structured trace record in
281  * /sys/kernel/debug/tracing/events/.
282  *
283  * A set of (un)registration functions can be passed to the variant
284  * TRACE_EVENT_FN to perform any (un)registration work.
285  */
286
287 #define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
288 #define DEFINE_EVENT(template, name, proto, args)               \
289         DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
290 #define DEFINE_EVENT_PRINT(template, name, proto, args, print)  \
291         DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
292
293 #define TRACE_EVENT(name, proto, args, struct, assign, print)   \
294         DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
295 #define TRACE_EVENT_FN(name, proto, args, struct,               \
296                 assign, print, reg, unreg)                      \
297         DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
298
299 #endif /* ifdef TRACE_EVENT (see note above) */