libmarkers/marker.h

   1 #ifndef _LINUX_MARKER_H
   2 #define _LINUX_MARKER_H
   3
   4 /*
   5  * Code markup for dynamic and static tracing.
   6  *
   7  * See Documentation/marker.txt.
   8  *
   9  * (C) Copyright 2006 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
  10  *
  11  * This file is released under the GPLv2.
  12  * See the file COPYING for more details.
  13  */
  14
  15 #include <stdarg.h>
  16 #include <linux/types.h>
  17 #include <linux/immediate.h>
  18 #include <linux/ltt-channels.h>
  19
  20 struct module;
  21 struct task_struct;
  22 struct marker;
  23
  24 /**
  25  * marker_probe_func - Type of a marker probe function
  26  * @mdata: marker data
  27  * @probe_private: probe private data
  28  * @call_private: call site private data
  29  * @fmt: format string
  30  * @args: variable argument list pointer. Use a pointer to overcome C's
  31  *        inability to pass this around as a pointer in a portable manner in
  32  *        the callee otherwise.
  33  *
  34  * Type of marker probe functions. They receive the mdata and need to parse the
  35  * format string to recover the variable argument list.
  36  */
  37 typedef void marker_probe_func(const struct marker *mdata,
  38                 void *probe_private, void *call_private,
  39                 const char *fmt, va_list *args);
  40
  41 struct marker_probe_closure {
  42         marker_probe_func *func;        /* Callback */
  43         void *probe_private;            /* Private probe data */
  44 };
  45
  46 struct marker {
  47         const char *channel;    /* Name of channel where to send data */
  48         const char *name;       /* Marker name */
  49         const char *format;     /* Marker format string, describing the
  50                                  * variable argument list.
  51                                  */
  52         DEFINE_IMV(char, state);/* Immediate value state. */
  53         char ptype;             /* probe type : 0 : single, 1 : multi */
  54                                 /* Probe wrapper */
  55         u16 channel_id;         /* Numeric channel identifier, dynamic */
  56         u16 event_id;           /* Numeric event identifier, dynamic */
  57         void (*call)(const struct marker *mdata, void *call_private, ...);
  58         struct marker_probe_closure single;
  59         struct marker_probe_closure *multi;
  60         const char *tp_name;    /* Optional tracepoint name */
  61         void *tp_cb;            /* Optional tracepoint callback */
  62 } __attribute__((aligned(8)));
  63
  64 #ifdef CONFIG_MARKERS
  65
  66 #define _DEFINE_MARKER(channel, name, tp_name_str, tp_cb, format)       \
  67                 static const char __mstrtab_##channel##_##name[]        \
  68                 __attribute__((section("__markers_strings")))           \
  69                 = #channel "\0" #name "\0" format;                      \
  70                 static struct marker __mark_##channel##_##name          \
  71                 __attribute__((section("__markers"), aligned(8))) =     \
  72                 { __mstrtab_##channel##_##name,                         \
  73                   &__mstrtab_##channel##_##name[sizeof(#channel)],      \
  74                   &__mstrtab_##channel##_##name[sizeof(#channel) +      \
  75                                                 sizeof(#name)],         \
  76                   0, 0, 0, 0, marker_probe_cb,                          \
  77                   { __mark_empty_function, NULL},                       \
  78                   NULL, tp_name_str, tp_cb }
  79
  80 #define DEFINE_MARKER(channel, name, format)                            \
  81                 _DEFINE_MARKER(channel, name, NULL, NULL, format)
  82
  83 #define DEFINE_MARKER_TP(channel, name, tp_name, tp_cb, format)         \
  84                 _DEFINE_MARKER(channel, name, #tp_name, tp_cb, format)
  85
  86 /*
  87  * Make sure the alignment of the structure in the __markers section will
  88  * not add unwanted padding between the beginning of the section and the
  89  * structure. Force alignment to the same alignment as the section start.
  90  *
  91  * The "generic" argument controls which marker enabling mechanism must be used.
  92  * If generic is true, a variable read is used.
  93  * If generic is false, immediate values are used.
  94  */
  95 #define __trace_mark(generic, channel, name, call_private, format, args...) \
  96         do {                                                            \
  97                 DEFINE_MARKER(channel, name, format);                   \
  98                 __mark_check_format(format, ## args);                   \
  99                 if (!generic) {                                         \
 100                         if (unlikely(imv_read(                          \
 101                                         __mark_##channel##_##name.state))) \
 102                                 (*__mark_##channel##_##name.call)       \
 103                                         (&__mark_##channel##_##name,    \
 104                                         call_private, ## args);         \
 105                 } else {                                                \
 106                         if (unlikely(_imv_read(                         \
 107                                         __mark_##channel##_##name.state))) \
 108                                 (*__mark_##channel##_##name.call)       \
 109                                         (&__mark_##channel##_##name,    \
 110                                         call_private, ## args);         \
 111                 }                                                       \
 112         } while (0)
 113
 114 #define __trace_mark_tp(channel, name, call_private, tp_name, tp_cb,    \
 115                         format, args...)                                \
 116         do {                                                            \
 117                 void __check_tp_type(void)                              \
 118                 {                                                       \
 119                         register_trace_##tp_name(tp_cb);                \
 120                 }                                                       \
 121                 DEFINE_MARKER_TP(channel, name, tp_name, tp_cb, format);\
 122                 __mark_check_format(format, ## args);                   \
 123                 (*__mark_##channel##_##name.call)(&__mark_##channel##_##name, \
 124                         call_private, ## args);                         \
 125         } while (0)
 126
 127 extern void marker_update_probe_range(struct marker *begin,
 128         struct marker *end);
 129
 130 #define GET_MARKER(channel, name)       (__mark_##channel##_##name)
 131
 132 #else /* !CONFIG_MARKERS */
 133 #define DEFINE_MARKER(channel, name, tp_name, tp_cb, format)
 134 #define __trace_mark(generic, channel, name, call_private, format, args...) \
 135                 __mark_check_format(format, ## args)
 136 #define __trace_mark_tp(channel, name, call_private, tp_name, tp_cb,    \
 137                 format, args...)                                        \
 138         do {                                                            \
 139                 void __check_tp_type(void)                              \
 140                 {                                                       \
 141                         register_trace_##tp_name(tp_cb);                \
 142                 }                                                       \
 143                 __mark_check_format(format, ## args);                   \
 144         } while (0)
 145 static inline void marker_update_probe_range(struct marker *begin,
 146         struct marker *end)
 147 { }
 148 #define GET_MARKER(channel, name)
 149 #endif /* CONFIG_MARKERS */
 150
 151 /**
 152  * trace_mark - Marker using code patching
 153  * @channel: marker channel (where to send the data), not quoted.
 154  * @name: marker name, not quoted.
 155  * @format: format string
 156  * @args...: variable argument list
 157  *
 158  * Places a marker using optimized code patching technique (imv_read())
 159  * to be enabled when immediate values are present.
 160  */
 161 #define trace_mark(channel, name, format, args...) \
 162         __trace_mark(0, channel, name, NULL, format, ## args)
 163
 164 /**
 165  * _trace_mark - Marker using variable read
 166  * @channel: marker channel (where to send the data), not quoted.
 167  * @name: marker name, not quoted.
 168  * @format: format string
 169  * @args...: variable argument list
 170  *
 171  * Places a marker using a standard memory read (_imv_read()) to be
 172  * enabled. Should be used for markers in code paths where instruction
 173  * modification based enabling is not welcome. (__init and __exit functions,
 174  * lockdep, some traps, printk).
 175  */
 176 #define _trace_mark(channel, name, format, args...) \
 177         __trace_mark(1, channel, name, NULL, format, ## args)
 178
 179 /**
 180  * trace_mark_tp - Marker in a tracepoint callback
 181  * @channel: marker channel (where to send the data), not quoted.
 182  * @name: marker name, not quoted.
 183  * @tp_name: tracepoint name, not quoted.
 184  * @tp_cb: tracepoint callback. Should have an associated global symbol so it
 185  *         is not optimized away by the compiler (should not be static).
 186  * @format: format string
 187  * @args...: variable argument list
 188  *
 189  * Places a marker in a tracepoint callback.
 190  */
 191 #define trace_mark_tp(channel, name, tp_name, tp_cb, format, args...)   \
 192         __trace_mark_tp(channel, name, NULL, tp_name, tp_cb, format, ## args)
 193
 194 /**
 195  * MARK_NOARGS - Format string for a marker with no argument.
 196  */
 197 #define MARK_NOARGS " "
 198
 199 extern void lock_markers(void);
 200 extern void unlock_markers(void);
 201
 202 extern void markers_compact_event_ids(void);
 203
 204 /* To be used for string format validity checking with gcc */
 205 static inline void __printf(1, 2) ___mark_check_format(const char *fmt, ...)
 206 {
 207 }
 208
 209 #define __mark_check_format(format, args...)                            \
 210         do {                                                            \
 211                 if (0)                                                  \
 212                         ___mark_check_format(format, ## args);          \
 213         } while (0)
 214
 215 extern marker_probe_func __mark_empty_function;
 216
 217 extern void marker_probe_cb(const struct marker *mdata,
 218         void *call_private, ...);
 219
 220 /*
 221  * Connect a probe to a marker.
 222  * private data pointer must be a valid allocated memory address, or NULL.
 223  */
 224 extern int marker_probe_register(const char *channel, const char *name,
 225         const char *format, marker_probe_func *probe, void *probe_private);
 226
 227 /*
 228  * Returns the private data given to marker_probe_register.
 229  */
 230 extern int marker_probe_unregister(const char *channel, const char *name,
 231         marker_probe_func *probe, void *probe_private);
 232 /*
 233  * Unregister a marker by providing the registered private data.
 234  */
 235 extern int marker_probe_unregister_private_data(marker_probe_func *probe,
 236         void *probe_private);
 237
 238 extern void *marker_get_private_data(const char *channel, const char *name,
 239         marker_probe_func *probe, int num);
 240
 241 /*
 242  * marker_synchronize_unregister must be called between the last marker probe
 243  * unregistration and the first one of
 244  * - the end of module exit function
 245  * - the free of any resource used by the probes
 246  * to ensure the code and data are valid for any possibly running probes.
 247  */
 248 #define marker_synchronize_unregister() synchronize_sched()
 249
 250 struct marker_iter {
 251         struct module *module;
 252         struct marker *marker;
 253 };
 254
 255 extern void marker_iter_start(struct marker_iter *iter);
 256 extern void marker_iter_next(struct marker_iter *iter);
 257 extern void marker_iter_stop(struct marker_iter *iter);
 258 extern void marker_iter_reset(struct marker_iter *iter);
 259 extern int marker_get_iter_range(struct marker **marker, struct marker *begin,
 260         struct marker *end);
 261
 262 extern void marker_update_process(void);
 263 extern int is_marker_enabled(const char *channel, const char *name);
 264
 265 #ifdef CONFIG_MARKERS_USERSPACE
 266 extern void exit_user_markers(struct task_struct *p);
 267 #else
 268 static inline void exit_user_markers(struct task_struct *p)
 269 {
 270 }
 271 #endif
 272
 273 #endif