libmarkers/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  *
   9  * This file is released under the GPLv2.
  10  * See the file COPYING for more details.
  11  */
  12
  13 #ifndef _LINUX_MARKER_H
  14 #define _LINUX_MARKER_H
  15
  16 #include <stdarg.h>
  17 //ust// #include <linux/types.h>
  18 #include "immediate.h"
  19 //ust// #include <linux/ltt-channels.h>
  20 #include "kernelcompat.h"
  21 #include "compiler.h"
  22 #include "list.h"
  23
  24 //ust// struct module;
  25 //ust// struct task_struct;
  26 struct marker;
  27
  28 /**
  29  * marker_probe_func - Type of a marker probe function
  30  * @mdata: marker data
  31  * @probe_private: probe private data
  32  * @call_private: call site private data
  33  * @fmt: format string
  34  * @args: variable argument list pointer. Use a pointer to overcome C's
  35  *        inability to pass this around as a pointer in a portable manner in
  36  *        the callee otherwise.
  37  *
  38  * Type of marker probe functions. They receive the mdata and need to parse the
  39  * format string to recover the variable argument list.
  40  */
  41 typedef void marker_probe_func(const struct marker *mdata,
  42                 void *probe_private, void *call_private,
  43                 const char *fmt, va_list *args);
  44
  45 struct marker_probe_closure {
  46         marker_probe_func *func;        /* Callback */
  47         void *probe_private;            /* Private probe data */
  48 };
  49
  50 struct marker {
  51         const char *channel;    /* Name of channel where to send data */
  52         const char *name;       /* Marker name */
  53         const char *format;     /* Marker format string, describing the
  54                                  * variable argument list.
  55                                  */
  56         DEFINE_IMV(char, state);/* Immediate value state. */
  57         char ptype;             /* probe type : 0 : single, 1 : multi */
  58                                 /* Probe wrapper */
  59         u16 channel_id;         /* Numeric channel identifier, dynamic */
  60         u16 event_id;           /* Numeric event identifier, dynamic */
  61         void (*call)(const struct marker *mdata, void *call_private, ...);
  62         struct marker_probe_closure single;
  63         struct marker_probe_closure *multi;
  64         const char *tp_name;    /* Optional tracepoint name */
  65         void *tp_cb;            /* Optional tracepoint callback */
  66 } __attribute__((aligned(8)));
  67
  68 //ust// #ifdef CONFIG_MARKERS
  69
  70 #define _DEFINE_MARKER(channel, name, tp_name_str, tp_cb, format)       \
  71                 static const char __mstrtab_##channel##_##name[]        \
  72                 __attribute__((section("__markers_strings")))           \
  73                 = #channel "\0" #name "\0" format;                      \
  74                 static struct marker __mark_##channel##_##name          \
  75                 __attribute__((section("__markers"), aligned(8))) =     \
  76                 { __mstrtab_##channel##_##name,                         \
  77                   &__mstrtab_##channel##_##name[sizeof(#channel)],      \
  78                   &__mstrtab_##channel##_##name[sizeof(#channel) +      \
  79                                                 sizeof(#name)],         \
  80                   0, 0, 0, 0, marker_probe_cb,                          \
  81                   { __mark_empty_function, NULL},                       \
  82                   NULL, tp_name_str, tp_cb }
  83
  84 #define DEFINE_MARKER(channel, name, format)                            \
  85                 _DEFINE_MARKER(channel, name, NULL, NULL, format)
  86
  87 #define DEFINE_MARKER_TP(channel, name, tp_name, tp_cb, format)         \
  88                 _DEFINE_MARKER(channel, name, #tp_name, tp_cb, format)
  89
  90 /*
  91  * Make sure the alignment of the structure in the __markers section will
  92  * not add unwanted padding between the beginning of the section and the
  93  * structure. Force alignment to the same alignment as the section start.
  94  *
  95  * The "generic" argument controls which marker enabling mechanism must be used.
  96  * If generic is true, a variable read is used.
  97  * If generic is false, immediate values are used.
  98  */
  99 #define __trace_mark(generic, channel, name, call_private, format, args...) \
 100         do {                                                            \
 101                 DEFINE_MARKER(channel, name, format);                   \
 102                 __mark_check_format(format, ## args);                   \
 103                 if (!generic) {                                         \
 104                         if (unlikely(imv_read(                          \
 105                                         __mark_##channel##_##name.state))) \
 106                                 (*__mark_##channel##_##name.call)       \
 107                                         (&__mark_##channel##_##name,    \
 108                                         call_private, ## args);         \
 109                 } else {                                                \
 110                         if (unlikely(_imv_read(                         \
 111                                         __mark_##channel##_##name.state))) \
 112                                 (*__mark_##channel##_##name.call)       \
 113                                         (&__mark_##channel##_##name,    \
 114                                         call_private, ## args);         \
 115                 }                                                       \
 116         } while (0)
 117
 118 #define __trace_mark_tp(channel, name, call_private, tp_name, tp_cb,    \
 119                         format, args...)                                \
 120         do {                                                            \
 121                 void __check_tp_type(void)                              \
 122                 {                                                       \
 123                         register_trace_##tp_name(tp_cb);                \
 124                 }                                                       \
 125                 DEFINE_MARKER_TP(channel, name, tp_name, tp_cb, format);\
 126                 __mark_check_format(format, ## args);                   \
 127                 (*__mark_##channel##_##name.call)(&__mark_##channel##_##name, \
 128                         call_private, ## args);                         \
 129         } while (0)
 130
 131 extern void marker_update_probe_range(struct marker *begin,
 132         struct marker *end);
 133
 134 #define GET_MARKER(channel, name)       (__mark_##channel##_##name)
 135
 136 //ust// #else /* !CONFIG_MARKERS */
 137 //ust// #define DEFINE_MARKER(channel, name, tp_name, tp_cb, format)
 138 //ust// #define __trace_mark(generic, channel, name, call_private, format, args...) \
 139 //ust//                 __mark_check_format(format, ## args)
 140 //ust// #define __trace_mark_tp(channel, name, call_private, tp_name, tp_cb,    \
 141 //ust//                 format, args...)                                        \
 142 //ust//         do {                                                            \
 143 //ust//                 void __check_tp_type(void)                              \
 144 //ust//                 {                                                       \
 145 //ust//                         register_trace_##tp_name(tp_cb);                \
 146 //ust//                 }                                                       \
 147 //ust//                 __mark_check_format(format, ## args);                   \
 148 //ust//         } while (0)
 149 //ust// static inline void marker_update_probe_range(struct marker *begin,
 150 //ust//         struct marker *end)
 151 //ust// { }
 152 //ust// #define GET_MARKER(channel, name)
 153 //ust// #endif /* CONFIG_MARKERS */
 154
 155 /**
 156  * trace_mark - Marker using code patching
 157  * @channel: marker channel (where to send the data), not quoted.
 158  * @name: marker name, not quoted.
 159  * @format: format string
 160  * @args...: variable argument list
 161  *
 162  * Places a marker using optimized code patching technique (imv_read())
 163  * to be enabled when immediate values are present.
 164  */
 165 #define trace_mark(channel, name, format, args...) \
 166         __trace_mark(0, channel, name, NULL, format, ## args)
 167
 168 /**
 169  * _trace_mark - Marker using variable read
 170  * @channel: marker channel (where to send the data), not quoted.
 171  * @name: marker name, not quoted.
 172  * @format: format string
 173  * @args...: variable argument list
 174  *
 175  * Places a marker using a standard memory read (_imv_read()) to be
 176  * enabled. Should be used for markers in code paths where instruction
 177  * modification based enabling is not welcome. (__init and __exit functions,
 178  * lockdep, some traps, printk).
 179  */
 180 #define _trace_mark(channel, name, format, args...) \
 181         __trace_mark(1, channel, name, NULL, format, ## args)
 182
 183 /**
 184  * trace_mark_tp - Marker in a tracepoint callback
 185  * @channel: marker channel (where to send the data), not quoted.
 186  * @name: marker name, not quoted.
 187  * @tp_name: tracepoint name, not quoted.
 188  * @tp_cb: tracepoint callback. Should have an associated global symbol so it
 189  *         is not optimized away by the compiler (should not be static).
 190  * @format: format string
 191  * @args...: variable argument list
 192  *
 193  * Places a marker in a tracepoint callback.
 194  */
 195 #define trace_mark_tp(channel, name, tp_name, tp_cb, format, args...)   \
 196         __trace_mark_tp(channel, name, NULL, tp_name, tp_cb, format, ## args)
 197
 198 /**
 199  * MARK_NOARGS - Format string for a marker with no argument.
 200  */
 201 #define MARK_NOARGS " "
 202
 203 extern void lock_markers(void);
 204 extern void unlock_markers(void);
 205
 206 extern void markers_compact_event_ids(void);
 207
 208 /* To be used for string format validity checking with gcc */
 209 static inline void __printf(1, 2) ___mark_check_format(const char *fmt, ...)
 210 {
 211 }
 212
 213 #define __mark_check_format(format, args...)                            \
 214         do {                                                            \
 215                 if (0)                                                  \
 216                         ___mark_check_format(format, ## args);          \
 217         } while (0)
 218
 219 extern marker_probe_func __mark_empty_function;
 220
 221 extern void marker_probe_cb(const struct marker *mdata,
 222         void *call_private, ...);
 223
 224 /*
 225  * Connect a probe to a marker.
 226  * private data pointer must be a valid allocated memory address, or NULL.
 227  */
 228 extern int marker_probe_register(const char *channel, const char *name,
 229         const char *format, marker_probe_func *probe, void *probe_private);
 230
 231 /*
 232  * Returns the private data given to marker_probe_register.
 233  */
 234 extern int marker_probe_unregister(const char *channel, const char *name,
 235         marker_probe_func *probe, void *probe_private);
 236 /*
 237  * Unregister a marker by providing the registered private data.
 238  */
 239 extern int marker_probe_unregister_private_data(marker_probe_func *probe,
 240         void *probe_private);
 241
 242 extern void *marker_get_private_data(const char *channel, const char *name,
 243         marker_probe_func *probe, int num);
 244
 245 /*
 246  * marker_synchronize_unregister must be called between the last marker probe
 247  * unregistration and the first one of
 248  * - the end of module exit function
 249  * - the free of any resource used by the probes
 250  * to ensure the code and data are valid for any possibly running probes.
 251  */
 252 #define marker_synchronize_unregister() synchronize_sched()
 253
 254 struct marker_iter {
 255 //ust// struct module *module;
 256         struct lib *lib;
 257         struct marker *marker;
 258 };
 259
 260 extern void marker_iter_start(struct marker_iter *iter);
 261 extern void marker_iter_next(struct marker_iter *iter);
 262 extern void marker_iter_stop(struct marker_iter *iter);
 263 extern void marker_iter_reset(struct marker_iter *iter);
 264 extern int marker_get_iter_range(struct marker **marker, struct marker *begin,
 265         struct marker *end);
 266
 267 extern void marker_update_process(void);
 268 extern int is_marker_enabled(const char *channel, const char *name);
 269
 270 //ust// #ifdef CONFIG_MARKERS_USERSPACE
 271 //ust// extern void exit_user_markers(struct task_struct *p);
 272 //ust// #else
 273 //ust// static inline void exit_user_markers(struct task_struct *p)
 274 //ust// {
 275 //ust// }
 276 //ust// #endif
 277
 278
 279 struct lib {
 280         struct marker *markers_start;
 281         int markers_count;
 282         struct list_head list;
 283 };
 284
 285 int marker_register_lib(struct marker *markers_start, int markers_count);
 286
 287 #define MARKER_LIB                                                                      \
 288 extern struct marker __start___markers[] __attribute__((visibility("hidden")));         \
 289 extern struct marker __stop___markers[] __attribute__((visibility("hidden")));          \
 290                                                                                         \
 291 static void __attribute__((constructor)) __markers__init(void)                          \
 292 {                                                                                       \
 293         marker_register_lib(__start___markers, (((long)__stop___markers)-((long)__start___markers))/sizeof(struct marker));\
 294 }
 295
 296 void marker_set_new_marker_cb(void (*cb)(struct marker *));
 297
 298 #endif