include/ust/marker.h

   1 /*
   2  * Code markup for dynamic and static tracing.
   3  *
   4  * See Documentation/marker.txt.
   5  *
   6  * (C) Copyright 2006 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
   7  * (C) Copyright 2009 Pierre-Marc Fournier <pierre-marc dot fournier at polymtl dot ca>
   8  * (C) Copyright 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   9  *
  10  * This library is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU Lesser General Public
  12  * License as published by the Free Software Foundation;
  13  * version 2.1 of the License.
  14  *
  15  * This library is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public
  21  * License along with this library; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  23  */
  24
  25 #ifndef _UST_MARKER_H
  26 #define _UST_MARKER_H
  27
  28 #include <stdarg.h>
  29 #include <ust/core.h>
  30 #include <urcu/list.h>
  31 #include <ust/kcompat/kcompat.h>
  32
  33 #include <bits/wordsize.h>
  34
  35 struct ust_marker;
  36
  37 /**
  38  * ust_marker_probe_func - Type of a marker probe function
  39  * @mdata: marker data
  40  * @probe_private: probe private data
  41  * @call_private: call site private data
  42  * @fmt: format string
  43  * @args: variable argument list pointer. Use a pointer to overcome C's
  44  *        inability to pass this around as a pointer in a portable manner in
  45  *        the callee otherwise.
  46  *
  47  * Type of marker probe functions. They receive the mdata and need to parse the
  48  * format string to recover the variable argument list.
  49  */
  50 typedef void ust_marker_probe_func(const struct ust_marker *mdata,
  51                 void *probe_private, void *call_private,
  52                 const char *fmt, va_list *args);
  53
  54 struct ust_marker_probe_closure {
  55         ust_marker_probe_func *func;    /* Callback */
  56         void *probe_private;            /* Private probe data */
  57 };
  58
  59 struct ust_marker {
  60         const char *channel;    /* Name of channel where to send data */
  61         const char *name;       /* Marker name */
  62         const char *format;     /* Marker format string, describing the
  63                                  * variable argument list.
  64                                  */
  65         char state;             /* State. */
  66         char ptype;             /* probe type : 0 : single, 1 : multi */
  67                                 /* Probe wrapper */
  68         u16 channel_id;         /* Numeric channel identifier, dynamic */
  69         u16 event_id;           /* Numeric event identifier, dynamic */
  70         void (*call)(const struct ust_marker *mdata, void *call_private, ...);
  71         struct ust_marker_probe_closure single;
  72         struct ust_marker_probe_closure *multi;
  73         const char *tp_name;    /* Optional tracepoint name */
  74         void *tp_cb;            /* Optional tracepoint callback */
  75 };
  76
  77 #define GET_UST_MARKER(name)            (__ust_marker_def_##name)
  78
  79 /*
  80  * We keep the "channel" as internal field for marker.c *only*. It will be
  81  * removed soon.
  82  */
  83
  84 /*
  85  * __ust_marker_ptrs section is not const (read-only) because it needs to be
  86  * read-write to let the linker apply relocations and keep the object PIC.
  87  */
  88 #define _DEFINE_UST_MARKER(channel, name, tp_name_str, tp_cb, format)   \
  89                 static const char __mstrtab_##channel##_##name[]        \
  90                 __attribute__((section("__ust_markers_strings")))       \
  91                 = #channel "\0" #name "\0" format;                      \
  92                 static struct ust_marker __ust_marker_def_##name        \
  93                 __attribute__((section("__ust_markers"))) =             \
  94                 { __mstrtab_##channel##_##name,                         \
  95                   &__mstrtab_##channel##_##name[sizeof(#channel)],      \
  96                   &__mstrtab_##channel##_##name[sizeof(#channel) +      \
  97                                                 sizeof(#name)],         \
  98                   0, 0, 0, 0, ust_marker_probe_cb,                      \
  99                   { __ust_marker_empty_function, NULL},                 \
 100                   NULL, tp_name_str, tp_cb };                           \
 101                 static struct ust_marker * __ust_marker_ptr_##name      \
 102                         __attribute__((used, section("__ust_marker_ptrs"))) =   \
 103                         &__ust_marker_def_##name
 104
 105 #define DEFINE_UST_MARKER(name, format)                                 \
 106                 _DEFINE_UST_MARKER(ust, name, NULL, NULL, format)
 107
 108 #define DEFINE_UST_MARKER_TP(name, tp_name, tp_cb, format)              \
 109                 _DEFINE_UST_MARKER(ust, name, #tp_name, tp_cb, format)
 110
 111 /*
 112  * Make sure the alignment of the structure in the __ust_marker section will
 113  * not add unwanted padding between the beginning of the section and the
 114  * structure. Force alignment to the same alignment as the section start.
 115  */
 116
 117 #define __ust_marker(channel, name, call_private, format, args...)      \
 118         do {                                                            \
 119                 _DEFINE_UST_MARKER(channel, name, NULL, NULL, format);  \
 120                 __ust_marker_check_format(format, ## args);             \
 121                 if (unlikely(__ust_marker_def_##name.state))            \
 122                         (__ust_marker_def_##name.call)                  \
 123                                 (&__ust_marker_def_##name, call_private,\
 124                                 ## args);                               \
 125         } while (0)
 126
 127 #define __ust_marker_tp(name, call_private, tp_name, tp_cb,             \
 128                         format, args...)                                \
 129         do {                                                            \
 130                 void __check_tp_type(void)                              \
 131                 {                                                       \
 132                         register_trace_##tp_name(tp_cb, call_private);  \
 133                 }                                                       \
 134                 DEFINE_UST_MARKER_TP(name, #tp_name, tp_cb, format);    \
 135                 __ust_marker_check_format(format, ## args);             \
 136                 (*__ust_marker_def_##name.call)                         \
 137                         (&__ust_marker_def_##name, call_private, ## args);      \
 138         } while (0)
 139
 140 extern void ust_marker_update_probe_range(struct ust_marker * const *begin,
 141         struct ust_marker * const *end);
 142
 143 /**
 144  * ust_marker - Marker using code patching
 145  * @name: marker name, not quoted.
 146  * @format: format string
 147  * @args...: variable argument list
 148  *
 149  * Places a marker at caller site.
 150  */
 151 #define ust_marker(name, format, args...) \
 152         __ust_marker(ust, name, NULL, format, ## args)
 153
 154
 155 /*
 156  * trace_mark() -- TO BE DEPRECATED
 157  * @channel: name prefix, not quoted. Ignored.
 158  * @name: marker name, not quoted.
 159  * @format: format string
 160  * @args...: variable argument list
 161  *
 162  * Kept as a compatibility API and will be *DEPRECATED* in favor of
 163  * ust_marker().
 164  */
 165 #define trace_mark(channel, name, format, args...)      \
 166         ust_marker(name, format, ## args)
 167
 168 /**
 169  * ust_marker_tp - Marker in a tracepoint callback
 170  * @name: marker name, not quoted.
 171  * @tp_name: tracepoint name, not quoted.
 172  * @tp_cb: tracepoint callback. Should have an associated global symbol so it
 173  *         is not optimized away by the compiler (should not be static).
 174  * @format: format string
 175  * @args...: variable argument list
 176  *
 177  * Places a marker in a tracepoint callback.
 178  */
 179 #define ust_marker_tp(name, tp_name, tp_cb, format, args...)    \
 180         __ust_marker_tp(ust, name, NULL, tp_name, tp_cb, format, ## args)
 181
 182 /**
 183  * UST_MARKER_NOARGS - Format string for a marker with no argument.
 184  */
 185 #define UST_MARKER_NOARGS " "
 186
 187 /**
 188  * MARKER_NOARGS - Compatibility API. Will be *DEPRECATED*. Use
 189  * UST_MARKER_NOARGS instead.
 190  */
 191 #define MARK_NOARGS     UST_MARKER_NOARGS
 192
 193 extern void lock_ust_marker(void);
 194 extern void unlock_ust_marker(void);
 195
 196 extern void ust_marker_compact_event_ids(void);
 197
 198 /* To be used for string format validity checking with gcc */
 199 static inline void __printf(1, 2) ___ust_marker_check_format(const char *fmt, ...)
 200 {
 201 }
 202
 203 #define __ust_marker_check_format(format, args...)                      \
 204         do {                                                            \
 205                 if (0)                                                  \
 206                         ___ust_marker_check_format(format, ## args);    \
 207         } while (0)
 208
 209 extern ust_marker_probe_func __ust_marker_empty_function;
 210
 211 extern void ust_marker_probe_cb(const struct ust_marker *mdata,
 212         void *call_private, ...);
 213
 214 /*
 215  * Connect a probe to a marker.
 216  * private data pointer must be a valid allocated memory address, or NULL.
 217  */
 218 extern int ust_marker_probe_register(const char *channel, const char *name,
 219         const char *format, ust_marker_probe_func *probe, void *probe_private);
 220
 221 /*
 222  * Returns the private data given to ust_marker_probe_register.
 223  */
 224 extern int ust_marker_probe_unregister(const char *channel, const char *name,
 225         ust_marker_probe_func *probe, void *probe_private);
 226 /*
 227  * Unregister a marker by providing the registered private data.
 228  */
 229 extern int ust_marker_probe_unregister_private_data(ust_marker_probe_func *probe,
 230         void *probe_private);
 231
 232 extern void *ust_marker_get_private_data(const char *channel, const char *name,
 233         ust_marker_probe_func *probe, int num);
 234
 235 /*
 236  * ust_marker_synchronize_unregister must be called between the last marker probe
 237  * unregistration and the first one of
 238  * - the end of module exit function
 239  * - the free of any resource used by the probes
 240  * to ensure the code and data are valid for any possibly running probes.
 241  */
 242 #define ust_marker_synchronize_unregister() synchronize_sched()
 243
 244 struct ust_marker_iter {
 245 //ust// struct module *module;
 246         struct ust_marker_lib *lib;
 247         struct ust_marker * const *ust_marker;
 248 };
 249
 250 extern void ust_marker_iter_start(struct ust_marker_iter *iter);
 251 extern void ust_marker_iter_next(struct ust_marker_iter *iter);
 252 extern void ust_marker_iter_stop(struct ust_marker_iter *iter);
 253 extern void ust_marker_iter_reset(struct ust_marker_iter *iter);
 254 extern int ust_marker_get_iter_range(struct ust_marker * const **marker, struct ust_marker * const *begin,
 255         struct ust_marker * const *end);
 256
 257 extern void ust_marker_update_process(void);
 258 extern int is_ust_marker_enabled(const char *channel, const char *name);
 259
 260 //ust// #ifdef CONFIG_UST_MARKER_USERSPACE
 261 //ust// extern void exit_user_ust_marker(struct task_struct *p);
 262 //ust// #else
 263 //ust// static inline void exit_user_ust_marker(struct task_struct *p)
 264 //ust// {
 265 //ust// }
 266 //ust// #endif
 267
 268 struct ust_marker_addr {
 269         struct ust_marker *marker;
 270         void *addr;
 271 };
 272
 273 struct ust_marker_lib {
 274         struct ust_marker * const *ust_marker_start;
 275         int ust_marker_count;
 276         struct cds_list_head list;
 277 };
 278
 279 extern int ust_marker_register_lib(struct ust_marker * const *ust_marker_start, int ust_marker_count);
 280 extern int ust_marker_unregister_lib(struct ust_marker * const *ust_marker_start);
 281
 282 #define UST_MARKER_LIB                                                  \
 283         extern struct ust_marker * const __start___ust_marker_ptrs[] __attribute__((weak, visibility("hidden"))); \
 284         extern struct ust_marker * const __stop___ust_marker_ptrs[] __attribute__((weak, visibility("hidden"))); \
 285         static struct ust_marker * __ust_marker_ptr_dummy               \
 286                 __attribute__((used, section("__ust_marker_ptrs")));    \
 287                                                                         \
 288         static void __attribute__((constructor)) __ust_marker__init(void)       \
 289         {                                                               \
 290                 ust_marker_register_lib(__start___ust_marker_ptrs,      \
 291                                     __stop___ust_marker_ptrs            \
 292                                     - __start___ust_marker_ptrs);               \
 293         }                                                               \
 294                                                                         \
 295         static void __attribute__((destructor)) __ust_marker__destroy(void)\
 296         {                                                               \
 297                 ust_marker_unregister_lib(__start___ust_marker_ptrs);   \
 298         }
 299
 300 /*
 301  * MARKER_LIB is kept for backward compatibility and will be
 302  * *DEPRECATED*. Use UST_MARKER_LIB instead.
 303  */
 304 #define MARKER_LIB      UST_MARKER_LIB
 305
 306 extern void ust_marker_set_new_ust_marker_cb(void (*cb)(struct ust_marker *));
 307 extern void init_ust_marker(void);
 308
 309 #endif /* _UST_MARKER_H */