libust/tracepoint.h

   1 #ifndef _LINUX_TRACEPOINT_H
   2 #define _LINUX_TRACEPOINT_H
   3
   4 /*
   5  * Copyright (C) 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
   6  * Copyright (C) 2009 Pierre-Marc Fournier
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * as published by the Free Software Foundation; either version 2
  11  * of the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  21  *
  22  * Heavily inspired from the Linux Kernel Markers.
  23  *
  24  * Ported to userspace by Pierre-Marc Fournier.
  25  */
  26
  27 //#include <linux/immediate.h>
  28 //#include <linux/types.h>
  29 //#include <linux/rcupdate.h>
  30
  31 #define _LGPL_SOURCE
  32 #include <urcu.h>
  33
  34 #include "immediate.h"
  35 #include "kernelcompat.h"
  36
  37 struct module;
  38 struct tracepoint;
  39
  40 struct tracepoint {
  41         const char *name;               /* Tracepoint name */
  42         DEFINE_IMV(char, state);        /* State. */
  43         void **funcs;
  44 } __attribute__((aligned(32)));         /*
  45                                          * Aligned on 32 bytes because it is
  46                                          * globally visible and gcc happily
  47                                          * align these on the structure size.
  48                                          * Keep in sync with vmlinux.lds.h.
  49                                          */
  50
  51 #define TPPROTO(args...)        args
  52 #define TPARGS(args...)         args
  53
  54 #define CONFIG_TRACEPOINTS
  55 #ifdef CONFIG_TRACEPOINTS
  56
  57 /*
  58  * it_func[0] is never NULL because there is at least one element in the array
  59  * when the array itself is non NULL.
  60  */
  61 #define __DO_TRACE(tp, proto, args)                                     \
  62         do {                                                            \
  63                 void **it_func;                                         \
  64                                                                         \
  65                 rcu_read_lock(); /*ust rcu_read_lock_sched_notrace();   */                      \
  66                 it_func = rcu_dereference((tp)->funcs);                 \
  67                 if (it_func) {                                          \
  68                         do {                                            \
  69                                 ((void(*)(proto))(*it_func))(args);     \
  70                         } while (*(++it_func));                         \
  71                 }                                                       \
  72                 rcu_read_unlock(); /*ust rcu_read_unlock_sched_notrace(); */                    \
  73         } while (0)
  74
  75 #define __CHECK_TRACE(name, generic, proto, args)                       \
  76         do {                                                            \
  77                 if (!generic) {                                         \
  78                         if (unlikely(imv_read(__tracepoint_##name.state))) \
  79                                 __DO_TRACE(&__tracepoint_##name,        \
  80                                         TPPROTO(proto), TPARGS(args));  \
  81                 } else {                                                \
  82                         if (unlikely(_imv_read(__tracepoint_##name.state))) \
  83                                 __DO_TRACE(&__tracepoint_##name,        \
  84                                         TPPROTO(proto), TPARGS(args));  \
  85                 }                                                       \
  86         } while (0)
  87
  88 /*
  89  * Make sure the alignment of the structure in the __tracepoints section will
  90  * not add unwanted padding between the beginning of the section and the
  91  * structure. Force alignment to the same alignment as the section start.
  92  *
  93  * The "generic" argument, passed to the declared __trace_##name inline
  94  * function controls which tracepoint enabling mechanism must be used.
  95  * If generic is true, a variable read is used.
  96  * If generic is false, immediate values are used.
  97  */
  98 #define DECLARE_TRACE(name, proto, args)                                \
  99         extern struct tracepoint __tracepoint_##name;                   \
 100         static inline void trace_##name(proto)                          \
 101         {                                                               \
 102                 __CHECK_TRACE(name, 0, TPPROTO(proto), TPARGS(args));   \
 103         }                                                               \
 104         static inline void _trace_##name(proto)                         \
 105         {                                                               \
 106                 __CHECK_TRACE(name, 1, TPPROTO(proto), TPARGS(args));   \
 107         }                                                               \
 108         static inline int register_trace_##name(void (*probe)(proto))   \
 109         {                                                               \
 110                 return tracepoint_probe_register(#name, (void *)probe); \
 111         }                                                               \
 112         static inline int unregister_trace_##name(void (*probe)(proto)) \
 113         {                                                               \
 114                 return tracepoint_probe_unregister(#name, (void *)probe);\
 115         }
 116
 117 #define DEFINE_TRACE(name)                                              \
 118         static const char __tpstrtab_##name[]                           \
 119         __attribute__((section("__tracepoints_strings"))) = #name;      \
 120         struct tracepoint __tracepoint_##name                           \
 121         __attribute__((section("__tracepoints"), aligned(32))) =        \
 122                 { __tpstrtab_##name, 0, NULL }
 123
 124 #define EXPORT_TRACEPOINT_SYMBOL_GPL(name)                              \
 125         EXPORT_SYMBOL_GPL(__tracepoint_##name)
 126 #define EXPORT_TRACEPOINT_SYMBOL(name)                                  \
 127         EXPORT_SYMBOL(__tracepoint_##name)
 128
 129 extern void tracepoint_update_probe_range(struct tracepoint *begin,
 130         struct tracepoint *end);
 131
 132 #else /* !CONFIG_TRACEPOINTS */
 133 #define DECLARE_TRACE(name, proto, args)                                \
 134         static inline void trace_##name(proto)                          \
 135         { }                                                             \
 136         static inline void _trace_##name(proto)                         \
 137         { }                                                             \
 138         static inline int register_trace_##name(void (*probe)(proto))   \
 139         {                                                               \
 140                 return -ENOSYS;                                         \
 141         }                                                               \
 142         static inline int unregister_trace_##name(void (*probe)(proto)) \
 143         {                                                               \
 144                 return -ENOSYS;                                         \
 145         }
 146
 147 #define DEFINE_TRACE(name)
 148 #define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
 149 #define EXPORT_TRACEPOINT_SYMBOL(name)
 150
 151 static inline void tracepoint_update_probe_range(struct tracepoint *begin,
 152         struct tracepoint *end)
 153 { }
 154 #endif /* CONFIG_TRACEPOINTS */
 155
 156 /*
 157  * Connect a probe to a tracepoint.
 158  * Internal API, should not be used directly.
 159  */
 160 extern int tracepoint_probe_register(const char *name, void *probe);
 161
 162 /*
 163  * Disconnect a probe from a tracepoint.
 164  * Internal API, should not be used directly.
 165  */
 166 extern int tracepoint_probe_unregister(const char *name, void *probe);
 167
 168 extern int tracepoint_probe_register_noupdate(const char *name, void *probe);
 169 extern int tracepoint_probe_unregister_noupdate(const char *name, void *probe);
 170 extern void tracepoint_probe_update_all(void);
 171
 172 struct tracepoint_iter {
 173 //ust// struct module *module;
 174         struct tracepoint_lib *lib;
 175         struct tracepoint *tracepoint;
 176 };
 177
 178 extern void tracepoint_iter_start(struct tracepoint_iter *iter);
 179 extern void tracepoint_iter_next(struct tracepoint_iter *iter);
 180 extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
 181 extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
 182 extern int tracepoint_get_iter_range(struct tracepoint **tracepoint,
 183         struct tracepoint *begin, struct tracepoint *end);
 184
 185 /*
 186  * tracepoint_synchronize_unregister must be called between the last tracepoint
 187  * probe unregistration and the end of module exit to make sure there is no
 188  * caller executing a probe when it is freed.
 189  */
 190 static inline void tracepoint_synchronize_unregister(void)
 191 {
 192         synchronize_sched();
 193 }
 194
 195 struct tracepoint_lib {
 196         struct tracepoint *tracepoints_start;
 197         int tracepoints_count;
 198         struct list_head list;
 199 };
 200
 201 extern int tracepoint_register_lib(struct tracepoint *tracepoints_start,
 202                                    int tracepoints_count);
 203
 204 #define TRACEPOINT_LIB                                                  \
 205         extern struct tracepoint __start___tracepoints[] __attribute__((visibility("hidden"))); \
 206         extern struct tracepoint __stop___tracepoints[] __attribute__((visibility("hidden"))); \
 207         static void __attribute__((constructor)) __tracepoints__init(void) \
 208         {                                                               \
 209                 tracepoint_register_lib(__start___tracepoints,          \
 210                                         (((long)__stop___tracepoints)-((long)__start___tracepoints))/sizeof(struct tracepoint)); \
 211         }
 212
 213 #endif