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  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  22  */
  23
  24 #ifndef _UST_MARKER_H
  25 #define _UST_MARKER_H
  26
  27 #include <stdarg.h>
  28 #include <ust/immediate.h>
  29 #include <ust/core.h>
  30 #include <urcu/list.h>
  31 #include <ust/processor.h>
  32 #include <ust/kcompat/kcompat.h>
  33 #include <ust/kcompat/stringify.h>
  34
  35 #include <bits/wordsize.h>
  36
  37 struct marker;
  38
  39 /**
  40  * marker_probe_func - Type of a marker probe function
  41  * @mdata: marker data
  42  * @probe_private: probe private data
  43  * @call_private: call site private data
  44  * @fmt: format string
  45  * @args: variable argument list pointer. Use a pointer to overcome C's
  46  *        inability to pass this around as a pointer in a portable manner in
  47  *        the callee otherwise.
  48  *
  49  * Type of marker probe functions. They receive the mdata and need to parse the
  50  * format string to recover the variable argument list.
  51  */
  52 typedef void marker_probe_func(const struct marker *mdata,
  53                 void *probe_private, struct registers *regs, void *call_private,
  54                 const char *fmt, va_list *args);
  55
  56 struct marker_probe_closure {
  57         marker_probe_func *func;        /* Callback */
  58         void *probe_private;            /* Private probe data */
  59 };
  60
  61 struct marker {
  62         const char *channel;    /* Name of channel where to send data */
  63         const char *name;       /* Marker name */
  64         const char *format;     /* Marker format string, describing the
  65                                  * variable argument list.
  66                                  */
  67         DEFINE_IMV(char, state);/* Immediate value state. */
  68         char ptype;             /* probe type : 0 : single, 1 : multi */
  69                                 /* Probe wrapper */
  70         u16 channel_id;         /* Numeric channel identifier, dynamic */
  71         u16 event_id;           /* Numeric event identifier, dynamic */
  72         void (*call)(const struct marker *mdata, void *call_private, struct registers *regs, ...);
  73         struct marker_probe_closure single;
  74         struct marker_probe_closure *multi;
  75         const char *tp_name;    /* Optional tracepoint name */
  76         void *tp_cb;            /* Optional tracepoint callback */
  77         void *location;         /* Address of marker in code */
  78 };
  79
  80 #define GET_MARKER(channel, name)       (__mark_##channel##_##name)
  81
  82 #define _DEFINE_MARKER(channel, name, tp_name_str, tp_cb, format, unique, m)                    \
  83                 struct registers regs;                                                          \
  84                                                                                                 \
  85                 /* This next asm has to be a basic inline asm (no input/output/clobber),        \
  86                  * because it must not require %-sign escaping, as we most certainly            \
  87                  * have some %-signs in the format string.                                      \
  88                  */                                                                             \
  89                 asm volatile (                                                                  \
  90                         /* We only define these symbols if they have not yet been defined. Indeed, \
  91                          * if two markers with the same channel/name are on the same line, they \
  92                          * will try to create the same symbols, resulting in a conflict. This   \
  93                          * is not unusual as it can be the result of function inlining.         \
  94                          */                                                                     \
  95                         ".ifndef __mstrtab_" __stringify(channel) "_" __stringify(name) "_channel_" __stringify(unique) "\n\t"  \
  96                         /*".section __markers_strings\n\t"*/                                    \
  97                         ".section __markers_strings,\"aw\"\n\t"                                 \
  98                         "__mstrtab_" __stringify(channel) "_" __stringify(name) "_channel_" __stringify(unique) ":\n\t" \
  99                         ".string \"" __stringify(channel) "\"\n\t"                                      \
 100                         "__mstrtab_" __stringify(channel) "_" __stringify(name) "_name_" __stringify(unique) ":\n\t"    \
 101                         ".string \"" __stringify(name) "\"\n\t"                                         \
 102                         "__mstrtab_" __stringify(channel) "_" __stringify(name) "_format_" __stringify(unique) ":\n\t"  \
 103                         ".string " "\"" format "\"" "\n\t"                                              \
 104                         ".previous\n\t"                                                         \
 105                         ".endif\n\t"                                                            \
 106                 );                                                                              \
 107                 asm volatile (                                                                  \
 108                         /*".section __markers\n\t"*/ \
 109                         ".section __markers,\"aw\"\n\t"                                         \
 110                         "2:\n\t" \
 111                         _ASM_PTR "(__mstrtab_" __stringify(channel) "_" __stringify(name) "_channel_" __stringify(unique) ")\n\t" /* channel string */ \
 112                         _ASM_PTR "(__mstrtab_" __stringify(channel) "_" __stringify(name) "_name_" __stringify(unique) ")\n\t" /* name string */ \
 113                         _ASM_PTR "(__mstrtab_" __stringify(channel) "_" __stringify(name) "_format_" __stringify(unique) ")\n\t" /* format string */ \
 114                         ".byte 0\n\t" /* state imv */                                           \
 115                         ".byte 0\n\t" /* ptype */                                                       \
 116                         ".word 0\n\t" /* channel_id */                                          \
 117                         ".word 0\n\t" /* event_id */                                            \
 118                         ".balign " __stringify(__WORDSIZE) " / 8\n\t" /* alignment */                   \
 119                         _ASM_PTR "(marker_probe_cb)\n\t" /* call */                             \
 120                         _ASM_PTR "(__mark_empty_function)\n\t" /* marker_probe_closure single.field1 */ \
 121                         _ASM_PTR "0\n\t" /* marker_probe_closure single.field2 */                       \
 122                         _ASM_PTR "0\n\t" /* marker_probe_closure *multi */                              \
 123                         _ASM_PTR "0\n\t" /* tp_name */                                          \
 124                         _ASM_PTR "0\n\t" /* tp_cb */                                            \
 125                         _ASM_PTR "(1f)\n\t" /* location */                                              \
 126                         ".previous\n\t"                                                         \
 127                         /*".section __markers_ptrs\n\t"*/ \
 128                         ".section __markers_ptrs,\"a\"\n\t"                                     \
 129                         ".balign 8\n\t"                                                         \
 130                         _ASM_PTR "(2b)\n\t"                                                     \
 131                         ".previous\n\t"                                                         \
 132                         "1:\n\t"                                                                \
 133                         ARCH_COPY_ADDR("%[outptr]")                                             \
 134                 : [outptr] "=r" (m) );                                                          \
 135                                                                                                 \
 136                 save_registers(&regs)
 137
 138
 139 #define DEFINE_MARKER(channel, name, format, unique, m)                         \
 140                 _DEFINE_MARKER(channel, name, NULL, NULL, format, unique, m)
 141
 142 #define DEFINE_MARKER_TP(channel, name, tp_name, tp_cb, format)         \
 143                 _DEFINE_MARKER_TP(channel, name, #tp_name, tp_cb, format)
 144
 145 #define _DEFINE_MARKER_TP(channel, name, tp_name_str, tp_cb, format) \
 146                 static const char __mstrtab_##channel##_##name[]        \
 147                 __attribute__((section("__markers_strings")))           \
 148                 = #channel "\0" #name "\0" format;                      \
 149                 static struct marker GET_MARKER(channel, name)          \
 150                 __attribute__((section("__markers"))) =                 \
 151                 { __mstrtab_##channel##_##name,                         \
 152                         &__mstrtab_##channel##_##name[sizeof(#channel)],        \
 153                         &__mstrtab_##channel##_##name[sizeof(#channel) + sizeof(#name)],                \
 154                         0, 0, 0, 0, marker_probe_cb,                            \
 155                         { __mark_empty_function, NULL},                 \
 156                         NULL, tp_name_str, tp_cb };                     \
 157                 static struct marker * const __mark_ptr_##channel##_##name      \
 158                         __attribute__((used, section("__markers_ptrs"))) =      \
 159                         &GET_MARKER(channel, name);
 160
 161 /*
 162  * Make sure the alignment of the structure in the __markers section will
 163  * not add unwanted padding between the beginning of the section and the
 164  * structure. Force alignment to the same alignment as the section start.
 165  *
 166  * The "generic" argument controls which marker enabling mechanism must be used.
 167  * If generic is true, a variable read is used.
 168  * If generic is false, immediate values are used.
 169  */
 170
 171 #define __trace_mark(generic, channel, name, call_private, format, args...) \
 172         __trace_mark_counter(generic, channel, name, __LINE__, call_private, format, ## args)
 173
 174 #define __trace_mark_counter(generic, channel, name, unique, call_private, format, args...) \
 175         do {                                                            \
 176                 struct marker *m;                                       \
 177                 DEFINE_MARKER(channel, name, format, unique, m);                        \
 178                 __mark_check_format(format, ## args);                   \
 179                 if (!generic) {                                         \
 180                         if (unlikely(imv_read(m->state))) \
 181                                 (m->call)(m, call_private, &regs, ## args);             \
 182                 } else {                                                \
 183                         if (unlikely(_imv_read(m->state))) \
 184                                 (m->call)(m, call_private, &regs, ## args);             \
 185                 }                                                       \
 186         } while (0)
 187
 188 #define __trace_mark_tp(channel, name, call_private, tp_name, tp_cb, format, args...) \
 189         __trace_mark_tp_counter(channel, name, __LINE__, call_private, tp_name, tp_cb, format, ## args)
 190
 191 #define __trace_mark_tp_counter(channel, name, unique, call_private, tp_name, tp_cb, format, args...) \
 192         do {                                                            \
 193                 struct registers regs;                                                          \
 194                 void __check_tp_type(void)                              \
 195                 {                                                       \
 196                         register_trace_##tp_name(tp_cb, call_private);          \
 197                 }                                                       \
 198                 DEFINE_MARKER_TP(channel, name, tp_name, tp_cb, format);\
 199                 __mark_check_format(format, ## args);                   \
 200                 (*GET_MARKER(channel, name).call)(&GET_MARKER(channel, name), \
 201                         call_private, &regs, ## args);                          \
 202         } while (0)
 203
 204 extern void marker_update_probe_range(struct marker * const *begin,
 205         struct marker * const *end);
 206
 207 /**
 208  * trace_mark - Marker using code patching
 209  * @channel: marker channel (where to send the data), not quoted.
 210  * @name: marker name, not quoted.
 211  * @format: format string
 212  * @args...: variable argument list
 213  *
 214  * Places a marker using optimized code patching technique (imv_read())
 215  * to be enabled when immediate values are present.
 216  */
 217 #define trace_mark(channel, name, format, args...) \
 218         __trace_mark(0, channel, name, NULL, format, ## args)
 219
 220 /**
 221  * _trace_mark - Marker using variable read
 222  * @channel: marker channel (where to send the data), not quoted.
 223  * @name: marker name, not quoted.
 224  * @format: format string
 225  * @args...: variable argument list
 226  *
 227  * Places a marker using a standard memory read (_imv_read()) to be
 228  * enabled. Should be used for markers in code paths where instruction
 229  * modification based enabling is not welcome.
 230  */
 231 #define _trace_mark(channel, name, format, args...) \
 232         __trace_mark(1, channel, name, NULL, format, ## args)
 233
 234 /**
 235  * trace_mark_tp - Marker in a tracepoint callback
 236  * @channel: marker channel (where to send the data), not quoted.
 237  * @name: marker name, not quoted.
 238  * @tp_name: tracepoint name, not quoted.
 239  * @tp_cb: tracepoint callback. Should have an associated global symbol so it
 240  *         is not optimized away by the compiler (should not be static).
 241  * @format: format string
 242  * @args...: variable argument list
 243  *
 244  * Places a marker in a tracepoint callback.
 245  */
 246 #define trace_mark_tp(channel, name, tp_name, tp_cb, format, args...)   \
 247         __trace_mark_tp(channel, name, NULL, tp_name, tp_cb, format, ## args)
 248
 249 /**
 250  * MARK_NOARGS - Format string for a marker with no argument.
 251  */
 252 #define MARK_NOARGS " "
 253
 254 extern void lock_markers(void);
 255 extern void unlock_markers(void);
 256
 257 extern void markers_compact_event_ids(void);
 258
 259 /* To be used for string format validity checking with gcc */
 260 static inline void __printf(1, 2) ___mark_check_format(const char *fmt, ...)
 261 {
 262 }
 263
 264 #define __mark_check_format(format, args...)                            \
 265         do {                                                            \
 266                 if (0)                                                  \
 267                         ___mark_check_format(format, ## args);          \
 268         } while (0)
 269
 270 extern marker_probe_func __mark_empty_function;
 271
 272 extern void marker_probe_cb(const struct marker *mdata,
 273         void *call_private, struct registers *regs, ...);
 274
 275 /*
 276  * Connect a probe to a marker.
 277  * private data pointer must be a valid allocated memory address, or NULL.
 278  */
 279 extern int marker_probe_register(const char *channel, const char *name,
 280         const char *format, marker_probe_func *probe, void *probe_private);
 281
 282 /*
 283  * Returns the private data given to marker_probe_register.
 284  */
 285 extern int marker_probe_unregister(const char *channel, const char *name,
 286         marker_probe_func *probe, void *probe_private);
 287 /*
 288  * Unregister a marker by providing the registered private data.
 289  */
 290 extern int marker_probe_unregister_private_data(marker_probe_func *probe,
 291         void *probe_private);
 292
 293 extern void *marker_get_private_data(const char *channel, const char *name,
 294         marker_probe_func *probe, int num);
 295
 296 /*
 297  * marker_synchronize_unregister must be called between the last marker probe
 298  * unregistration and the first one of
 299  * - the end of module exit function
 300  * - the free of any resource used by the probes
 301  * to ensure the code and data are valid for any possibly running probes.
 302  */
 303 #define marker_synchronize_unregister() synchronize_sched()
 304
 305 struct marker_iter {
 306 //ust// struct module *module;
 307         struct lib *lib;
 308         struct marker * const *marker;
 309 };
 310
 311 extern void marker_iter_start(struct marker_iter *iter);
 312 extern void marker_iter_next(struct marker_iter *iter);
 313 extern void marker_iter_stop(struct marker_iter *iter);
 314 extern void marker_iter_reset(struct marker_iter *iter);
 315 extern int marker_get_iter_range(struct marker * const **marker, struct marker * const *begin,
 316         struct marker * const *end);
 317
 318 extern void marker_update_process(void);
 319 extern int is_marker_enabled(const char *channel, const char *name);
 320
 321 //ust// #ifdef CONFIG_MARKERS_USERSPACE
 322 //ust// extern void exit_user_markers(struct task_struct *p);
 323 //ust// #else
 324 //ust// static inline void exit_user_markers(struct task_struct *p)
 325 //ust// {
 326 //ust// }
 327 //ust// #endif
 328
 329 struct marker_addr {
 330         struct marker *marker;
 331         void *addr;
 332 };
 333
 334 struct lib {
 335         struct marker * const *markers_start;
 336 #ifdef CONFIG_UST_GDB_INTEGRATION
 337         struct marker_addr *markers_addr_start;
 338 #endif
 339         int markers_count;
 340         struct cds_list_head list;
 341 };
 342
 343 extern int marker_register_lib(struct marker * const *markers_start, int markers_count);
 344 extern int marker_unregister_lib(struct marker * const *markers_start);
 345
 346 #define MARKER_LIB                                                      \
 347         extern struct marker * const __start___markers_ptrs[] __attribute__((weak, visibility("hidden"))); \
 348         extern struct marker * const __stop___markers_ptrs[] __attribute__((weak, visibility("hidden"))); \
 349                                                                         \
 350         static void __attribute__((constructor)) __markers__init(void)  \
 351         {                                                               \
 352                 marker_register_lib(__start___markers_ptrs,             \
 353                                     __stop___markers_ptrs               \
 354                                     - __start___markers_ptrs);          \
 355         }                                                               \
 356                                                                         \
 357         static void __attribute__((destructor)) __markers__destroy(void)\
 358         {                                                               \
 359                 marker_unregister_lib(__start___markers_ptrs);          \
 360         }
 361
 362 extern void marker_set_new_marker_cb(void (*cb)(struct marker *));
 363 extern void init_markers(void);
 364
 365 #endif /* _UST_MARKER_H */