/*
* Kernel Tracepoint API.
*
- * See Documentation/tracepoint.txt.
+ * See Documentation/trace/tracepoints.txt.
*
* (C) Copyright 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
*
struct tracepoint {
const char *name; /* Tracepoint name */
int state; /* State. */
+ void (*regfunc)(void);
+ void (*unregfunc)(void);
void **funcs;
} __attribute__((aligned(32))); /*
* Aligned on 32 bytes because it is
* Keep in sync with vmlinux.lds.h.
*/
-#define TPPROTO(args...) args
-#define TPARGS(args...) args
+/*
+ * Connect a probe to a tracepoint.
+ * Internal API, should not be used directly.
+ */
+extern int tracepoint_probe_register(const char *name, void *probe);
+
+/*
+ * Disconnect a probe from a tracepoint.
+ * Internal API, should not be used directly.
+ */
+extern int tracepoint_probe_unregister(const char *name, void *probe);
+
+extern int tracepoint_probe_register_noupdate(const char *name, void *probe);
+extern int tracepoint_probe_unregister_noupdate(const char *name, void *probe);
+extern void tracepoint_probe_update_all(void);
+
+struct tracepoint_iter {
+ struct module *module;
+ struct tracepoint *tracepoint;
+};
+
+extern void tracepoint_iter_start(struct tracepoint_iter *iter);
+extern void tracepoint_iter_next(struct tracepoint_iter *iter);
+extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
+extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
+extern int tracepoint_get_iter_range(struct tracepoint **tracepoint,
+ struct tracepoint *begin, struct tracepoint *end);
+
+/*
+ * tracepoint_synchronize_unregister must be called between the last tracepoint
+ * probe unregistration and the end of module exit to make sure there is no
+ * caller executing a probe when it is freed.
+ */
+static inline void tracepoint_synchronize_unregister(void)
+{
+ synchronize_sched();
+}
+
+#define PARAMS(args...) args
+
+#ifdef CONFIG_TRACEPOINTS
+extern void tracepoint_update_probe_range(struct tracepoint *begin,
+ struct tracepoint *end);
+#else
+static inline void tracepoint_update_probe_range(struct tracepoint *begin,
+ struct tracepoint *end)
+{ }
+#endif /* CONFIG_TRACEPOINTS */
+
+#endif /* _LINUX_TRACEPOINT_H */
+
+/*
+ * Note: we keep the TRACE_EVENT and DECLARE_TRACE outside the include
+ * file ifdef protection.
+ * This is due to the way trace events work. If a file includes two
+ * trace event headers under one "CREATE_TRACE_POINTS" the first include
+ * will override the TRACE_EVENT and break the second include.
+ */
+
+#ifndef DECLARE_TRACE
+
+#define TP_PROTO(args...) args
+#define TP_ARGS(args...) args
#ifdef CONFIG_TRACEPOINTS
void **it_func; \
\
rcu_read_lock_sched_notrace(); \
- it_func = rcu_dereference((tp)->funcs); \
+ it_func = rcu_dereference_sched((tp)->funcs); \
if (it_func) { \
do { \
((void(*)(proto))(*it_func))(args); \
{ \
if (unlikely(__tracepoint_##name.state)) \
__DO_TRACE(&__tracepoint_##name, \
- TPPROTO(proto), TPARGS(args)); \
+ TP_PROTO(proto), TP_ARGS(args)); \
} \
static inline int register_trace_##name(void (*probe)(proto)) \
{ \
return tracepoint_probe_unregister(#name, (void *)probe);\
}
-#define DEFINE_TRACE(name) \
+
+#define DEFINE_TRACE_FN(name, reg, unreg) \
static const char __tpstrtab_##name[] \
__attribute__((section("__tracepoints_strings"))) = #name; \
struct tracepoint __tracepoint_##name \
__attribute__((section("__tracepoints"), aligned(32))) = \
- { __tpstrtab_##name, 0, NULL }
+ { __tpstrtab_##name, 0, reg, unreg, NULL }
+
+#define DEFINE_TRACE(name) \
+ DEFINE_TRACE_FN(name, NULL, NULL);
#define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \
EXPORT_SYMBOL_GPL(__tracepoint_##name)
#define EXPORT_TRACEPOINT_SYMBOL(name) \
EXPORT_SYMBOL(__tracepoint_##name)
-extern void tracepoint_update_probe_range(struct tracepoint *begin,
- struct tracepoint *end);
-
#else /* !CONFIG_TRACEPOINTS */
#define DECLARE_TRACE(name, proto, args) \
static inline void _do_trace_##name(struct tracepoint *tp, proto) \
return -ENOSYS; \
}
+#define DEFINE_TRACE_FN(name, reg, unreg)
#define DEFINE_TRACE(name)
#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
#define EXPORT_TRACEPOINT_SYMBOL(name)
-static inline void tracepoint_update_probe_range(struct tracepoint *begin,
- struct tracepoint *end)
-{ }
#endif /* CONFIG_TRACEPOINTS */
+#endif /* DECLARE_TRACE */
+#ifndef TRACE_EVENT
/*
- * Connect a probe to a tracepoint.
- * Internal API, should not be used directly.
- */
-extern int tracepoint_probe_register(const char *name, void *probe);
-
-/*
- * Disconnect a probe from a tracepoint.
- * Internal API, should not be used directly.
+ * For use with the TRACE_EVENT macro:
+ *
+ * We define a tracepoint, its arguments, its printk format
+ * and its 'fast binay record' layout.
+ *
+ * Firstly, name your tracepoint via TRACE_EVENT(name : the
+ * 'subsystem_event' notation is fine.
+ *
+ * Think about this whole construct as the
+ * 'trace_sched_switch() function' from now on.
+ *
+ *
+ * TRACE_EVENT(sched_switch,
+ *
+ * *
+ * * A function has a regular function arguments
+ * * prototype, declare it via TP_PROTO():
+ * *
+ *
+ * TP_PROTO(struct rq *rq, struct task_struct *prev,
+ * struct task_struct *next),
+ *
+ * *
+ * * Define the call signature of the 'function'.
+ * * (Design sidenote: we use this instead of a
+ * * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
+ * *
+ *
+ * TP_ARGS(rq, prev, next),
+ *
+ * *
+ * * Fast binary tracing: define the trace record via
+ * * TP_STRUCT__entry(). You can think about it like a
+ * * regular C structure local variable definition.
+ * *
+ * * This is how the trace record is structured and will
+ * * be saved into the ring buffer. These are the fields
+ * * that will be exposed to user-space in
+ * * /sys/kernel/debug/tracing/events/<*>/format.
+ * *
+ * * The declared 'local variable' is called '__entry'
+ * *
+ * * __field(pid_t, prev_prid) is equivalent to a standard declariton:
+ * *
+ * * pid_t prev_pid;
+ * *
+ * * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to:
+ * *
+ * * char prev_comm[TASK_COMM_LEN];
+ * *
+ *
+ * TP_STRUCT__entry(
+ * __array( char, prev_comm, TASK_COMM_LEN )
+ * __field( pid_t, prev_pid )
+ * __field( int, prev_prio )
+ * __array( char, next_comm, TASK_COMM_LEN )
+ * __field( pid_t, next_pid )
+ * __field( int, next_prio )
+ * ),
+ *
+ * *
+ * * Assign the entry into the trace record, by embedding
+ * * a full C statement block into TP_fast_assign(). You
+ * * can refer to the trace record as '__entry' -
+ * * otherwise you can put arbitrary C code in here.
+ * *
+ * * Note: this C code will execute every time a trace event
+ * * happens, on an active tracepoint.
+ * *
+ *
+ * TP_fast_assign(
+ * memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
+ * __entry->prev_pid = prev->pid;
+ * __entry->prev_prio = prev->prio;
+ * memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
+ * __entry->next_pid = next->pid;
+ * __entry->next_prio = next->prio;
+ * )
+ *
+ * *
+ * * Formatted output of a trace record via TP_printk().
+ * * This is how the tracepoint will appear under ftrace
+ * * plugins that make use of this tracepoint.
+ * *
+ * * (raw-binary tracing wont actually perform this step.)
+ * *
+ *
+ * TP_printk("task %s:%d [%d] ==> %s:%d [%d]",
+ * __entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
+ * __entry->next_comm, __entry->next_pid, __entry->next_prio),
+ *
+ * );
+ *
+ * This macro construct is thus used for the regular printk format
+ * tracing setup, it is used to construct a function pointer based
+ * tracepoint callback (this is used by programmatic plugins and
+ * can also by used by generic instrumentation like SystemTap), and
+ * it is also used to expose a structured trace record in
+ * /sys/kernel/debug/tracing/events/.
+ *
+ * A set of (un)registration functions can be passed to the variant
+ * TRACE_EVENT_FN to perform any (un)registration work.
*/
-extern int tracepoint_probe_unregister(const char *name, void *probe);
-
-extern int tracepoint_probe_register_noupdate(const char *name, void *probe);
-extern int tracepoint_probe_unregister_noupdate(const char *name, void *probe);
-extern void tracepoint_probe_update_all(void);
-struct tracepoint_iter {
- struct module *module;
- struct tracepoint *tracepoint;
-};
-
-extern void tracepoint_iter_start(struct tracepoint_iter *iter);
-extern void tracepoint_iter_next(struct tracepoint_iter *iter);
-extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
-extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
-extern int tracepoint_get_iter_range(struct tracepoint **tracepoint,
- struct tracepoint *begin, struct tracepoint *end);
+#define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
+#define DEFINE_EVENT(template, name, proto, args) \
+ DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
+#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
+ DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
-/*
- * tracepoint_synchronize_unregister must be called between the last tracepoint
- * probe unregistration and the end of module exit to make sure there is no
- * caller executing a probe when it is freed.
- */
-static inline void tracepoint_synchronize_unregister(void)
-{
- synchronize_sched();
-}
+#define TRACE_EVENT(name, proto, args, struct, assign, print) \
+ DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
+#define TRACE_EVENT_FN(name, proto, args, struct, \
+ assign, print, reg, unreg) \
+ DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
-#endif
+#endif /* ifdef TRACE_EVENT (see note above) */