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-rw-r--r--include/linux/tracepoint.h95
1 files changed, 72 insertions, 23 deletions
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 8d5e4f6d96d..9a59d1f98cd 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -20,12 +20,17 @@
struct module;
struct tracepoint;
+struct tracepoint_func {
+ void *func;
+ void *data;
+};
+
struct tracepoint {
const char *name; /* Tracepoint name */
int state; /* State. */
void (*regfunc)(void);
void (*unregfunc)(void);
- void **funcs;
+ struct tracepoint_func *funcs;
} __attribute__((aligned(32))); /*
* Aligned on 32 bytes because it is
* globally visible and gcc happily
@@ -37,16 +42,19 @@ struct tracepoint {
* Connect a probe to a tracepoint.
* Internal API, should not be used directly.
*/
-extern int tracepoint_probe_register(const char *name, void *probe);
+extern int tracepoint_probe_register(const char *name, void *probe, void *data);
/*
* 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_unregister(const char *name, void *probe, void *data);
-extern int tracepoint_probe_register_noupdate(const char *name, void *probe);
-extern int tracepoint_probe_unregister_noupdate(const char *name, void *probe);
+extern int tracepoint_probe_register_noupdate(const char *name, void *probe,
+ void *data);
+extern int tracepoint_probe_unregister_noupdate(const char *name, void *probe,
+ void *data);
extern void tracepoint_probe_update_all(void);
struct tracepoint_iter {
@@ -102,17 +110,27 @@ static inline void tracepoint_update_probe_range(struct tracepoint *begin,
/*
* it_func[0] is never NULL because there is at least one element in the array
* when the array itself is non NULL.
+ *
+ * Note, the proto and args passed in includes "__data" as the first parameter.
+ * The reason for this is to handle the "void" prototype. If a tracepoint
+ * has a "void" prototype, then it is invalid to declare a function
+ * as "(void *, void)". The DECLARE_TRACE_NOARGS() will pass in just
+ * "void *data", where as the DECLARE_TRACE() will pass in "void *data, proto".
*/
#define __DO_TRACE(tp, proto, args) \
do { \
- void **it_func; \
+ struct tracepoint_func *it_func_ptr; \
+ void *it_func; \
+ void *__data; \
\
rcu_read_lock_sched_notrace(); \
- it_func = rcu_dereference_sched((tp)->funcs); \
- if (it_func) { \
+ it_func_ptr = rcu_dereference_sched((tp)->funcs); \
+ if (it_func_ptr) { \
do { \
- ((void(*)(proto))(*it_func))(args); \
- } while (*(++it_func)); \
+ it_func = (it_func_ptr)->func; \
+ __data = (it_func_ptr)->data; \
+ ((void(*)(proto))(it_func))(args); \
+ } while ((++it_func_ptr)->func); \
} \
rcu_read_unlock_sched_notrace(); \
} while (0)
@@ -122,23 +140,29 @@ static inline void tracepoint_update_probe_range(struct tracepoint *begin,
* not add unwanted padding between the beginning of the section and the
* structure. Force alignment to the same alignment as the section start.
*/
-#define DECLARE_TRACE(name, proto, args) \
+#define __DECLARE_TRACE(name, proto, args, data_proto, data_args) \
extern struct tracepoint __tracepoint_##name; \
static inline void trace_##name(proto) \
{ \
if (unlikely(__tracepoint_##name.state)) \
__DO_TRACE(&__tracepoint_##name, \
- TP_PROTO(proto), TP_ARGS(args)); \
+ TP_PROTO(data_proto), \
+ TP_ARGS(data_args)); \
} \
- static inline int register_trace_##name(void (*probe)(proto)) \
+ static inline int \
+ register_trace_##name(void (*probe)(data_proto), void *data) \
{ \
- return tracepoint_probe_register(#name, (void *)probe); \
+ return tracepoint_probe_register(#name, (void *)probe, \
+ data); \
} \
- static inline int unregister_trace_##name(void (*probe)(proto)) \
+ static inline int \
+ unregister_trace_##name(void (*probe)(data_proto), void *data) \
{ \
- return tracepoint_probe_unregister(#name, (void *)probe);\
+ return tracepoint_probe_unregister(#name, (void *)probe, \
+ data); \
} \
- static inline void check_trace_callback_type_##name(void (*cb)(proto)) \
+ static inline void \
+ check_trace_callback_type_##name(void (*cb)(data_proto)) \
{ \
}
@@ -158,20 +182,22 @@ static inline void tracepoint_update_probe_range(struct tracepoint *begin,
EXPORT_SYMBOL(__tracepoint_##name)
#else /* !CONFIG_TRACEPOINTS */
-#define DECLARE_TRACE(name, proto, args) \
- static inline void _do_trace_##name(struct tracepoint *tp, proto) \
- { } \
+#define __DECLARE_TRACE(name, proto, args, data_proto, data_args) \
static inline void trace_##name(proto) \
{ } \
- static inline int register_trace_##name(void (*probe)(proto)) \
+ static inline int \
+ register_trace_##name(void (*probe)(data_proto), \
+ void *data) \
{ \
return -ENOSYS; \
} \
- static inline int unregister_trace_##name(void (*probe)(proto)) \
+ static inline int \
+ unregister_trace_##name(void (*probe)(data_proto), \
+ void *data) \
{ \
return -ENOSYS; \
} \
- static inline void check_trace_callback_type_##name(void (*cb)(proto)) \
+ static inline void check_trace_callback_type_##name(void (*cb)(data_proto)) \
{ \
}
@@ -181,6 +207,29 @@ static inline void tracepoint_update_probe_range(struct tracepoint *begin,
#define EXPORT_TRACEPOINT_SYMBOL(name)
#endif /* CONFIG_TRACEPOINTS */
+
+/*
+ * The need for the DECLARE_TRACE_NOARGS() is to handle the prototype
+ * (void). "void" is a special value in a function prototype and can
+ * not be combined with other arguments. Since the DECLARE_TRACE()
+ * macro adds a data element at the beginning of the prototype,
+ * we need a way to differentiate "(void *data, proto)" from
+ * "(void *data, void)". The second prototype is invalid.
+ *
+ * DECLARE_TRACE_NOARGS() passes "void" as the tracepoint prototype
+ * and "void *__data" as the callback prototype.
+ *
+ * DECLARE_TRACE() passes "proto" as the tracepoint protoype and
+ * "void *__data, proto" as the callback prototype.
+ */
+#define DECLARE_TRACE_NOARGS(name) \
+ __DECLARE_TRACE(name, void, , void *__data, __data)
+
+#define DECLARE_TRACE(name, proto, args) \
+ __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \
+ PARAMS(void *__data, proto), \
+ PARAMS(__data, args))
+
#endif /* DECLARE_TRACE */
#ifndef TRACE_EVENT