1 #ifndef _LINUX_TRACEPOINT_H 2 #define _LINUX_TRACEPOINT_H 3 4 /* 5 * Kernel Tracepoint API. 6 * 7 * See Documentation/tracepoint.txt. 8 * 9 * (C) Copyright 2008 Mathieu Desnoyers <[email protected]> 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 **funcs; 27 } __attribute__((aligned(8))); 28 29 30 #define TPPROTO(args...) args 31 #define TPARGS(args...) args 32 33 #ifdef CONFIG_TRACEPOINTS 34 35 /* 36 * it_func[0] is never NULL because there is at least one element in the array 37 * when the array itself is non NULL. 38 */ 39 #define __DO_TRACE(tp, proto, args) \ 40 do { \ 41 void **it_func; \ 42 \ 43 rcu_read_lock_sched(); \ 44 it_func = rcu_dereference((tp)->funcs); \ 45 if (it_func) { \ 46 do { \ 47 ((void(*)(proto))(*it_func))(args); \ 48 } while (*(++it_func)); \ 49 } \ 50 rcu_read_unlock_sched(); \ 51 } while (0) 52 53 /* 54 * Make sure the alignment of the structure in the __tracepoints section will 55 * not add unwanted padding between the beginning of the section and the 56 * structure. Force alignment to the same alignment as the section start. 57 */ 58 #define DEFINE_TRACE(name, proto, args) \ 59 static inline void trace_##name(proto) \ 60 { \ 61 static const char __tpstrtab_##name[] \ 62 __attribute__((section("__tracepoints_strings"))) \ 63 = #name ":" #proto; \ 64 static struct tracepoint __tracepoint_##name \ 65 __attribute__((section("__tracepoints"), aligned(8))) = \ 66 { __tpstrtab_##name, 0, NULL }; \ 67 if (unlikely(__tracepoint_##name.state)) \ 68 __DO_TRACE(&__tracepoint_##name, \ 69 TPPROTO(proto), TPARGS(args)); \ 70 } \ 71 static inline int register_trace_##name(void (*probe)(proto)) \ 72 { \ 73 return tracepoint_probe_register(#name ":" #proto, \ 74 (void *)probe); \ 75 } \ 76 static inline void unregister_trace_##name(void (*probe)(proto))\ 77 { \ 78 tracepoint_probe_unregister(#name ":" #proto, \ 79 (void *)probe); \ 80 } 81 82 extern void tracepoint_update_probe_range(struct tracepoint *begin, 83 struct tracepoint *end); 84 85 #else /* !CONFIG_TRACEPOINTS */ 86 #define DEFINE_TRACE(name, proto, args) \ 87 static inline void _do_trace_##name(struct tracepoint *tp, proto) \ 88 { } \ 89 static inline void trace_##name(proto) \ 90 { } \ 91 static inline int register_trace_##name(void (*probe)(proto)) \ 92 { \ 93 return -ENOSYS; \ 94 } \ 95 static inline void unregister_trace_##name(void (*probe)(proto))\ 96 { } 97 98 static inline void tracepoint_update_probe_range(struct tracepoint *begin, 99 struct tracepoint *end) 100 { } 101 #endif /* CONFIG_TRACEPOINTS */ 102 103 /* 104 * Connect a probe to a tracepoint. 105 * Internal API, should not be used directly. 106 */ 107 extern int tracepoint_probe_register(const char *name, void *probe); 108 109 /* 110 * Disconnect a probe from a tracepoint. 111 * Internal API, should not be used directly. 112 */ 113 extern int tracepoint_probe_unregister(const char *name, void *probe); 114 115 struct tracepoint_iter { 116 struct module *module; 117 struct tracepoint *tracepoint; 118 }; 119 120 extern void tracepoint_iter_start(struct tracepoint_iter *iter); 121 extern void tracepoint_iter_next(struct tracepoint_iter *iter); 122 extern void tracepoint_iter_stop(struct tracepoint_iter *iter); 123 extern void tracepoint_iter_reset(struct tracepoint_iter *iter); 124 extern int tracepoint_get_iter_range(struct tracepoint **tracepoint, 125 struct tracepoint *begin, struct tracepoint *end); 126 127 /* 128 * tracepoint_synchronize_unregister must be called between the last tracepoint 129 * probe unregistration and the end of module exit to make sure there is no 130 * caller executing a probe when it is freed. 131 */ 132 static inline void tracepoint_synchronize_unregister(void) 133 { 134 synchronize_sched(); 135 } 136 137 #endif 138