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/kernelcompat.h>
  30 #include <urcu/list.h>
  31 #include <ust/processor.h>
  32
  33 #include <bits/wordsize.h>
  34
  35 struct marker;
  36
  37 /* To stringify the expansion of a define */
  38 #define XSTR(d) STR(d)
  39 #define STR(s) #s
  40
  41 /**
  42  * marker_probe_func - Type of a marker probe function
  43  * @mdata: marker data
  44  * @probe_private: probe private data
  45  * @call_private: call site private data
  46  * @fmt: format string
  47  * @args: variable argument list pointer. Use a pointer to overcome C's
  48  *        inability to pass this around as a pointer in a portable manner in
  49  *        the callee otherwise.
  50  *
  51  * Type of marker probe functions. They receive the mdata and need to parse the
  52  * format string to recover the variable argument list.
  53  */
  54 typedef void marker_probe_func(const struct marker *mdata,
  55                 void *probe_private, struct registers *regs, void *call_private,
  56                 const char *fmt, va_list *args);
  57
  58 struct marker_probe_closure {
  59         marker_probe_func *func;        /* Callback */
  60         void *probe_private;            /* Private probe data */
  61 };
  62
  63 struct marker {
  64         const char *channel;    /* Name of channel where to send data */
  65         const char *name;       /* Marker name */
  66         const char *format;     /* Marker format string, describing the
  67                                  * variable argument list.
  68                                  */
  69         DEFINE_IMV(char, state);/* Immediate value state. */
  70         char ptype;             /* probe type : 0 : single, 1 : multi */
  71                                 /* Probe wrapper */
  72         u16 channel_id;         /* Numeric channel identifier, dynamic */
  73         u16 event_id;           /* Numeric event identifier, dynamic */
  74         void (*call)(const struct marker *mdata, void *call_private, struct registers *regs, ...);
  75         struct marker_probe_closure single;
  76         struct marker_probe_closure *multi;
  77         const char *tp_name;    /* Optional tracepoint name */
  78         void *tp_cb;            /* Optional tracepoint callback */
  79         void *location;         /* Address of marker in code */
  80 } __attribute__((aligned(8)));
  81
  82 #define CONFIG_MARKERS
  83 #ifdef CONFIG_MARKERS
  84
  85 #define _DEFINE_MARKER(channel, name, tp_name_str, tp_cb, format, unique, m)                    \
  86                 struct registers regs;                                                          \
  87                                                                                                 \
  88                 /* This next asm has to be a basic inline asm (no input/output/clobber),        \
  89                  * because it must not require %-sign escaping, as we most certainly            \
  90                  * have some %-signs in the format string.                                      \
  91                  */                                                                             \
  92                 asm volatile (                                                                  \
  93                      /* We only define these symbols if they have not yet been defined. Indeed, \
  94                       * if two markers with the same channel/name are on the same line, they    \
  95                       * will try to create the same symbols, resulting in a conflict. This      \
  96                       * is not unusual as it can be the result of function inlining.            \
  97                       */                                                                        \
  98                      ".ifndef __mstrtab_" XSTR(channel) "_" XSTR(name) "_channel_" XSTR(unique) "\n\t"  \
  99                      /*".section __markers_strings\n\t"*/                                       \
 100                      ".section __markers_strings,\"aw\",@progbits\n\t"                          \
 101                      "__mstrtab_" XSTR(channel) "_" XSTR(name) "_channel_" XSTR(unique) ":\n\t" \
 102                      ".string \"" XSTR(channel) "\"\n\t"                                        \
 103                      "__mstrtab_" XSTR(channel) "_" XSTR(name) "_name_" XSTR(unique) ":\n\t"    \
 104                      ".string \"" XSTR(name) "\"\n\t"                                           \
 105                      "__mstrtab_" XSTR(channel) "_" XSTR(name) "_format_" XSTR(unique) ":\n\t"  \
 106                      ".string " "\"" format "\"" "\n\t"                                         \
 107                      ".previous\n\t"                                                            \
 108                      ".endif\n\t"                                                               \
 109                 );                                                                              \
 110                 asm volatile (                                                                  \
 111                      /*".section __markers\n\t"*/ \
 112                      ".section __markers,\"aw\",@progbits\n\t"                                  \
 113                      ".balign 8\n\t"                                                            \
 114                      "2:\n\t" \
 115                      _ASM_PTR "(__mstrtab_" XSTR(channel) "_" XSTR(name) "_channel_" XSTR(unique) ")\n\t" /* channel string */ \
 116                      _ASM_PTR "(__mstrtab_" XSTR(channel) "_" XSTR(name) "_name_" XSTR(unique) ")\n\t" /* name string */ \
 117                      _ASM_PTR "(__mstrtab_" XSTR(channel) "_" XSTR(name) "_format_" XSTR(unique) ")\n\t" /* format string */ \
 118                      ".byte 0\n\t" /* state imv */                                              \
 119                      ".byte 0\n\t" /* ptype */                                                  \
 120                      ".word 0\n\t" /* channel_id */                                             \
 121                      ".word 0\n\t" /* event_id */                                               \
 122                      ".balign " XSTR(__WORDSIZE) " / 8\n\t" /* alignment */                     \
 123                      _ASM_PTR "(marker_probe_cb)\n\t" /* call */                                \
 124                      _ASM_PTR "(__mark_empty_function)\n\t" /* marker_probe_closure single.field1 */ \
 125                      _ASM_PTR "0\n\t" /* marker_probe_closure single.field2 */                  \
 126                      _ASM_PTR "0\n\t" /* marker_probe_closure *multi */                         \
 127                      _ASM_PTR "0\n\t" /* tp_name */                                             \
 128                      _ASM_PTR "0\n\t" /* tp_cb */                                               \
 129                      _ASM_PTR "(1f)\n\t" /* location */                                         \
 130                      ".previous\n\t"                                                            \
 131                      ARCH_COPY_ADDR("%[outptr]")                                                \
 132                      "1:\n\t"                                                                   \
 133                 : [outptr] "=r" (m) );                                                          \
 134                                                                                                 \
 135                 save_registers(&regs)
 136
 137
 138 #define DEFINE_MARKER(channel, name, format, unique, m)                         \
 139                 _DEFINE_MARKER(channel, name, NULL, NULL, format, unique, m)
 140
 141 #define DEFINE_MARKER_TP(channel, name, tp_name, tp_cb, format)         \
 142                 _DEFINE_MARKER_TP(channel, name, #tp_name, tp_cb, format)
 143
 144 #define _DEFINE_MARKER_TP(channel, name, tp_name_str, tp_cb, format) \
 145                 static const char __mstrtab_##channel##_##name[]        \
 146                 __attribute__((section("__markers_strings")))           \
 147                 = #channel "\0" #name "\0" format;                      \
 148                 static struct marker __mark_##channel##_##name          \
 149                 __attribute__((section("__markers"), aligned(8))) =     \
 150                 { __mstrtab_##channel##_##name,                         \
 151                   &__mstrtab_##channel##_##name[sizeof(#channel)],      \
 152                   &__mstrtab_##channel##_##name[sizeof(#channel) +      \
 153                                                 sizeof(#name)],         \
 154                   0, 0, 0, 0, marker_probe_cb,                          \
 155                   { __mark_empty_function, NULL},                       \
 156                   NULL, tp_name_str, tp_cb }
 157
 158 /*
 159  * Make sure the alignment of the structure in the __markers section will
 160  * not add unwanted padding between the beginning of the section and the
 161  * structure. Force alignment to the same alignment as the section start.
 162  *
 163  * The "generic" argument controls which marker enabling mechanism must be used.
 164  * If generic is true, a variable read is used.
 165  * If generic is false, immediate values are used.
 166  */
 167
 168 #define __trace_mark(generic, channel, name, call_private, format, args...) \
 169         __trace_mark_counter(generic, channel, name, __LINE__, call_private, format, ## args)
 170
 171 #define __trace_mark_counter(generic, channel, name, unique, call_private, format, args...) \
 172         do {                                                            \
 173                 struct marker *m;                                       \
 174                 DEFINE_MARKER(channel, name, format, unique, m);                        \
 175                 __mark_check_format(format, ## args);                   \
 176                 if (!generic) {                                         \
 177                         if (unlikely(imv_read(m->state))) \
 178                                 (m->call)(m, call_private, &regs, ## args);             \
 179                 } else {                                                \
 180                         if (unlikely(_imv_read(m->state))) \
 181                                 (m->call)(m, call_private, &regs, ## args);             \
 182                 }                                                       \
 183         } while (0)
 184
 185 #define __trace_mark_tp(channel, name, call_private, tp_name, tp_cb, format, args...) \
 186         __trace_mark_tp_counter(channel, name, __LINE__, call_private, tp_name, tp_cb, format, ## args)
 187
 188 #define __trace_mark_tp_counter(channel, name, unique, call_private, tp_name, tp_cb, format, args...) \
 189         do {                                                            \
 190                 struct marker m;                                        \
 191                 void __check_tp_type(void)                              \
 192                 {                                                       \
 193                         register_trace_##tp_name(tp_cb);                \
 194                 }                                                       \
 195                 DEFINE_MARKER_TP(channel, name, tp_name, tp_cb, format, unique, m);\
 196                 __mark_check_format(format, ## args);                   \
 197                 (*__mark_##channel##_##name.call)(&__mark_##channel##_##name, \
 198                         call_private, &regs, ## args);                          \
 199         } while (0)
 200
 201 extern void marker_update_probe_range(struct marker *begin,
 202         struct marker *end);
 203
 204 #define GET_MARKER(channel, name)       (__mark_##channel##_##name)
 205
 206 #else /* !CONFIG_MARKERS */
 207 #define DEFINE_MARKER(channel, name, tp_name, tp_cb, format, m)
 208 #define __trace_mark(generic, channel, name, call_private, format, args...) \
 209                 __mark_check_format(format, ## args)
 210 #define __trace_mark_tp(channel, name, call_private, tp_name, tp_cb,    \
 211                 format, args...)                                        \
 212         do {                                                            \
 213                 void __check_tp_type(void)                              \
 214                 {                                                       \
 215                         register_trace_##tp_name(tp_cb);                \
 216                 }                                                       \
 217                 __mark_check_format(format, ## args);                   \
 218         } while (0)
 219 static inline void marker_update_probe_range(struct marker *begin,
 220         struct marker *end)
 221 { }
 222 #define GET_MARKER(channel, name)
 223 #endif /* CONFIG_MARKERS */
 224
 225 /**
 226  * trace_mark - Marker using code patching
 227  * @channel: marker channel (where to send the data), not quoted.
 228  * @name: marker name, not quoted.
 229  * @format: format string
 230  * @args...: variable argument list
 231  *
 232  * Places a marker using optimized code patching technique (imv_read())
 233  * to be enabled when immediate values are present.
 234  */
 235 #define trace_mark(channel, name, format, args...) \
 236         __trace_mark(0, channel, name, NULL, format, ## args)
 237
 238 /**
 239  * _trace_mark - Marker using variable read
 240  * @channel: marker channel (where to send the data), not quoted.
 241  * @name: marker name, not quoted.
 242  * @format: format string
 243  * @args...: variable argument list
 244  *
 245  * Places a marker using a standard memory read (_imv_read()) to be
 246  * enabled. Should be used for markers in code paths where instruction
 247  * modification based enabling is not welcome.
 248  */
 249 #define _trace_mark(channel, name, format, args...) \
 250         __trace_mark(1, channel, name, NULL, format, ## args)
 251
 252 /**
 253  * trace_mark_tp - Marker in a tracepoint callback
 254  * @channel: marker channel (where to send the data), not quoted.
 255  * @name: marker name, not quoted.
 256  * @tp_name: tracepoint name, not quoted.
 257  * @tp_cb: tracepoint callback. Should have an associated global symbol so it
 258  *         is not optimized away by the compiler (should not be static).
 259  * @format: format string
 260  * @args...: variable argument list
 261  *
 262  * Places a marker in a tracepoint callback.
 263  */
 264 #define trace_mark_tp(channel, name, tp_name, tp_cb, format, args...)   \
 265         __trace_mark_tp(channel, name, NULL, tp_name, tp_cb, format, ## args)
 266
 267 /**
 268  * MARK_NOARGS - Format string for a marker with no argument.
 269  */
 270 #define MARK_NOARGS " "
 271
 272 extern void lock_markers(void);
 273 extern void unlock_markers(void);
 274
 275 extern void markers_compact_event_ids(void);
 276
 277 /* To be used for string format validity checking with gcc */
 278 static inline void __printf(1, 2) ___mark_check_format(const char *fmt, ...)
 279 {
 280 }
 281
 282 #define __mark_check_format(format, args...)                            \
 283         do {                                                            \
 284                 if (0)                                                  \
 285                         ___mark_check_format(format, ## args);          \
 286         } while (0)
 287
 288 extern marker_probe_func __mark_empty_function;
 289
 290 extern void marker_probe_cb(const struct marker *mdata,
 291         void *call_private, struct registers *regs, ...);
 292
 293 /*
 294  * Connect a probe to a marker.
 295  * private data pointer must be a valid allocated memory address, or NULL.
 296  */
 297 extern int marker_probe_register(const char *channel, const char *name,
 298         const char *format, marker_probe_func *probe, void *probe_private);
 299
 300 /*
 301  * Returns the private data given to marker_probe_register.
 302  */
 303 extern int marker_probe_unregister(const char *channel, const char *name,
 304         marker_probe_func *probe, void *probe_private);
 305 /*
 306  * Unregister a marker by providing the registered private data.
 307  */
 308 extern int marker_probe_unregister_private_data(marker_probe_func *probe,
 309         void *probe_private);
 310
 311 extern void *marker_get_private_data(const char *channel, const char *name,
 312         marker_probe_func *probe, int num);
 313
 314 /*
 315  * marker_synchronize_unregister must be called between the last marker probe
 316  * unregistration and the first one of
 317  * - the end of module exit function
 318  * - the free of any resource used by the probes
 319  * to ensure the code and data are valid for any possibly running probes.
 320  */
 321 #define marker_synchronize_unregister() synchronize_sched()
 322
 323 struct marker_iter {
 324 //ust// struct module *module;
 325         struct lib *lib;
 326         struct marker *marker;
 327 };
 328
 329 extern void marker_iter_start(struct marker_iter *iter);
 330 extern void marker_iter_next(struct marker_iter *iter);
 331 extern void marker_iter_stop(struct marker_iter *iter);
 332 extern void marker_iter_reset(struct marker_iter *iter);
 333 extern int marker_get_iter_range(struct marker **marker, struct marker *begin,
 334         struct marker *end);
 335
 336 extern void marker_update_process(void);
 337 extern int is_marker_enabled(const char *channel, const char *name);
 338
 339 //ust// #ifdef CONFIG_MARKERS_USERSPACE
 340 //ust// extern void exit_user_markers(struct task_struct *p);
 341 //ust// #else
 342 //ust// static inline void exit_user_markers(struct task_struct *p)
 343 //ust// {
 344 //ust// }
 345 //ust// #endif
 346
 347 struct marker_addr {
 348         struct marker *marker;
 349         void *addr;
 350 };
 351
 352 struct lib {
 353         struct marker *markers_start;
 354 #ifdef CONFIG_UST_GDB_INTEGRATION
 355         struct marker_addr *markers_addr_start;
 356 #endif
 357         int markers_count;
 358         struct list_head list;
 359 };
 360
 361 extern int marker_register_lib(struct marker *markers_start, int markers_count);
 362 extern int marker_unregister_lib(struct marker *markers_start);
 363
 364 #define MARKER_LIB                                                      \
 365         extern struct marker __start___markers[] __attribute__((weak, visibility("hidden"))); \
 366         extern struct marker __stop___markers[] __attribute__((weak, visibility("hidden"))); \
 367                                                                         \
 368         static void __attribute__((constructor)) __markers__init(void)  \
 369         {                                                               \
 370                 marker_register_lib(__start___markers, (((long)__stop___markers)-((long)__start___markers))/sizeof(struct marker)); \
 371         } \
 372         \
 373         static void __attribute__((destructor)) __markers__destroy(void)        \
 374         {                                                               \
 375                 marker_unregister_lib(__start___markers); \
 376         }
 377
 378 extern void marker_set_new_marker_cb(void (*cb)(struct marker *));
 379 extern void init_markers(void);
 380
 381 #endif /* _UST_MARKER_H */