libust/serialize.c

   1 /*
   2  * LTTng serializing code.
   3  *
   4  * Copyright Mathieu Desnoyers, March 2007.
   5  *
   6  * Licensed under the GPLv2.
   7  *
   8  * See this discussion about weirdness about passing va_list and then va_list to
   9  * functions. (related to array argument passing). va_list seems to be
  10  * implemented as an array on x86_64, but not on i386... This is why we pass a
  11  * va_list * to ltt_vtrace.
  12  */
  13
  14 #include <stdarg.h>
  15 //ust// #include <linux/ctype.h>
  16 //ust// #include <linux/string.h>
  17 //ust// #include <linux/module.h>
  18 //ust// #include <linux/ltt-tracer.h>
  19 #include <string.h>
  20 #include <stdint.h>
  21 #include "kernelcompat.h"
  22 #include "relay.h"
  23 #include "tracer.h"
  24 #include "list.h"
  25 #include "usterr.h"
  26
  27 enum ltt_type {
  28         LTT_TYPE_SIGNED_INT,
  29         LTT_TYPE_UNSIGNED_INT,
  30         LTT_TYPE_STRING,
  31         LTT_TYPE_NONE,
  32 };
  33
  34 #define LTT_ATTRIBUTE_NETWORK_BYTE_ORDER (1<<1)
  35
  36 /*
  37  * Inspired from vsnprintf
  38  *
  39  * The serialization format string supports the basic printf format strings.
  40  * In addition, it defines new formats that can be used to serialize more
  41  * complex/non portable data structures.
  42  *
  43  * Typical use:
  44  *
  45  * field_name %ctype
  46  * field_name #tracetype %ctype
  47  * field_name #tracetype %ctype1 %ctype2 ...
  48  *
  49  * A conversion is performed between format string types supported by GCC and
  50  * the trace type requested. GCC type is used to perform type checking on format
  51  * strings. Trace type is used to specify the exact binary representation
  52  * in the trace. A mapping is done between one or more GCC types to one trace
  53  * type. Sign extension, if required by the conversion, is performed following
  54  * the trace type.
  55  *
  56  * If a gcc format is not declared with a trace format, the gcc format is
  57  * also used as binary representation in the trace.
  58  *
  59  * Strings are supported with %s.
  60  * A single tracetype (sequence) can take multiple c types as parameter.
  61  *
  62  * c types:
  63  *
  64  * see printf(3).
  65  *
  66  * Note: to write a uint32_t in a trace, the following expression is recommended
  67  * si it can be portable:
  68  *
  69  * ("#4u%lu", (unsigned long)var)
  70  *
  71  * trace types:
  72  *
  73  * Serialization specific formats :
  74  *
  75  * Fixed size integers
  76  * #1u     writes uint8_t
  77  * #2u     writes uint16_t
  78  * #4u     writes uint32_t
  79  * #8u     writes uint64_t
  80  * #1d     writes int8_t
  81  * #2d     writes int16_t
  82  * #4d     writes int32_t
  83  * #8d     writes int64_t
  84  * i.e.:
  85  * #1u%lu #2u%lu #4d%lu #8d%lu #llu%hu #d%lu
  86  *
  87  * * Attributes:
  88  *
  89  * n:  (for network byte order)
  90  * #ntracetype%ctype
  91  *            is written in the trace in network byte order.
  92  *
  93  * i.e.: #bn4u%lu, #n%lu, #b%u
  94  *
  95  * TODO (eventually)
  96  * Variable length sequence
  97  * #a #tracetype1 #tracetype2 %array_ptr %elem_size %num_elems
  98  *            In the trace:
  99  *            #a specifies that this is a sequence
 100  *            #tracetype1 is the type of elements in the sequence
 101  *            #tracetype2 is the type of the element count
 102  *            GCC input:
 103  *            array_ptr is a pointer to an array that contains members of size
 104  *            elem_size.
 105  *            num_elems is the number of elements in the array.
 106  * i.e.: #a #lu #lu %p %lu %u
 107  *
 108  * Callback
 109  * #k         callback (taken from the probe data)
 110  *            The following % arguments are exepected by the callback
 111  *
 112  * i.e.: #a #lu #lu #k %p
 113  *
 114  * Note: No conversion is done from floats to integers, nor from integers to
 115  * floats between c types and trace types. float conversion from double to float
 116  * or from float to double is also not supported.
 117  *
 118  * REMOVE
 119  * %*b     expects sizeof(data), data
 120  *         where sizeof(data) is 1, 2, 4 or 8
 121  *
 122  * Fixed length struct, union or array.
 123  * FIXME: unable to extract those sizes statically.
 124  * %*r     expects sizeof(*ptr), ptr
 125  * %*.*r   expects sizeof(*ptr), __alignof__(*ptr), ptr
 126  * struct and unions removed.
 127  * Fixed length array:
 128  * [%p]#a[len #tracetype]
 129  * i.e.: [%p]#a[12 #lu]
 130  *
 131  * Variable length sequence
 132  * %*.*:*v expects sizeof(*ptr), __alignof__(*ptr), elem_num, ptr
 133  *         where elem_num is the number of elements in the sequence
 134  */
 135 static inline const char *parse_trace_type(const char *fmt,
 136                 char *trace_size, enum ltt_type *trace_type,
 137                 unsigned long *attributes)
 138 {
 139         int qualifier;          /* 'h', 'l', or 'L' for integer fields */
 140                                 /* 'z' support added 23/7/1999 S.H.    */
 141                                 /* 'z' changed to 'Z' --davidm 1/25/99 */
 142                                 /* 't' added for ptrdiff_t */
 143
 144         /* parse attributes. */
 145 repeat:
 146         switch (*fmt) {
 147         case 'n':
 148                 *attributes |= LTT_ATTRIBUTE_NETWORK_BYTE_ORDER;
 149                 ++fmt;
 150                 goto repeat;
 151         }
 152
 153         /* get the conversion qualifier */
 154         qualifier = -1;
 155         if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' ||
 156             *fmt == 'Z' || *fmt == 'z' || *fmt == 't' ||
 157             *fmt == 'S' || *fmt == '1' || *fmt == '2' ||
 158             *fmt == '4' || *fmt == 8) {
 159                 qualifier = *fmt;
 160                 ++fmt;
 161                 if (qualifier == 'l' && *fmt == 'l') {
 162                         qualifier = 'L';
 163                         ++fmt;
 164                 }
 165         }
 166
 167         switch (*fmt) {
 168         case 'c':
 169                 *trace_type = LTT_TYPE_UNSIGNED_INT;
 170                 *trace_size = sizeof(unsigned char);
 171                 goto parse_end;
 172         case 's':
 173                 *trace_type = LTT_TYPE_STRING;
 174                 goto parse_end;
 175         case 'p':
 176                 *trace_type = LTT_TYPE_UNSIGNED_INT;
 177                 *trace_size = sizeof(void *);
 178                 goto parse_end;
 179         case 'd':
 180         case 'i':
 181                 *trace_type = LTT_TYPE_SIGNED_INT;
 182                 break;
 183         case 'o':
 184         case 'u':
 185         case 'x':
 186         case 'X':
 187                 *trace_type = LTT_TYPE_UNSIGNED_INT;
 188                 break;
 189         default:
 190                 if (!*fmt)
 191                         --fmt;
 192                 goto parse_end;
 193         }
 194         switch (qualifier) {
 195         case 'L':
 196                 *trace_size = sizeof(long long);
 197                 break;
 198         case 'l':
 199                 *trace_size = sizeof(long);
 200                 break;
 201         case 'Z':
 202         case 'z':
 203                 *trace_size = sizeof(size_t);
 204                 break;
 205 //ust// case 't':
 206 //ust//         *trace_size = sizeof(ptrdiff_t);
 207 //ust//         break;
 208         case 'h':
 209                 *trace_size = sizeof(short);
 210                 break;
 211         case '1':
 212                 *trace_size = sizeof(uint8_t);
 213                 break;
 214         case '2':
 215                 *trace_size = sizeof(uint16_t);
 216                 break;
 217         case '4':
 218                 *trace_size = sizeof(uint32_t);
 219                 break;
 220         case '8':
 221                 *trace_size = sizeof(uint64_t);
 222                 break;
 223         default:
 224                 *trace_size = sizeof(int);
 225         }
 226
 227 parse_end:
 228         return fmt;
 229 }
 230
 231 /*
 232  * Restrictions:
 233  * Field width and precision are *not* supported.
 234  * %n not supported.
 235  */
 236 static inline const char *parse_c_type(const char *fmt,
 237                 char *c_size, enum ltt_type *c_type)
 238 {
 239         int qualifier;          /* 'h', 'l', or 'L' for integer fields */
 240                                 /* 'z' support added 23/7/1999 S.H.    */
 241                                 /* 'z' changed to 'Z' --davidm 1/25/99 */
 242                                 /* 't' added for ptrdiff_t */
 243
 244         /* process flags : ignore standard print formats for now. */
 245 repeat:
 246         switch (*fmt) {
 247         case '-':
 248         case '+':
 249         case ' ':
 250         case '#':
 251         case '0':
 252                 ++fmt;
 253                 goto repeat;
 254         }
 255
 256         /* get the conversion qualifier */
 257         qualifier = -1;
 258         if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' ||
 259             *fmt == 'Z' || *fmt == 'z' || *fmt == 't' ||
 260             *fmt == 'S') {
 261                 qualifier = *fmt;
 262                 ++fmt;
 263                 if (qualifier == 'l' && *fmt == 'l') {
 264                         qualifier = 'L';
 265                         ++fmt;
 266                 }
 267         }
 268
 269         switch (*fmt) {
 270         case 'c':
 271                 *c_type = LTT_TYPE_UNSIGNED_INT;
 272                 *c_size = sizeof(unsigned char);
 273                 goto parse_end;
 274         case 's':
 275                 *c_type = LTT_TYPE_STRING;
 276                 goto parse_end;
 277         case 'p':
 278                 *c_type = LTT_TYPE_UNSIGNED_INT;
 279                 *c_size = sizeof(void *);
 280                 goto parse_end;
 281         case 'd':
 282         case 'i':
 283                 *c_type = LTT_TYPE_SIGNED_INT;
 284                 break;
 285         case 'o':
 286         case 'u':
 287         case 'x':
 288         case 'X':
 289                 *c_type = LTT_TYPE_UNSIGNED_INT;
 290                 break;
 291         default:
 292                 if (!*fmt)
 293                         --fmt;
 294                 goto parse_end;
 295         }
 296         switch (qualifier) {
 297         case 'L':
 298                 *c_size = sizeof(long long);
 299                 break;
 300         case 'l':
 301                 *c_size = sizeof(long);
 302                 break;
 303         case 'Z':
 304         case 'z':
 305                 *c_size = sizeof(size_t);
 306                 break;
 307 //ust// case 't':
 308 //ust//         *c_size = sizeof(ptrdiff_t);
 309 //ust//         break;
 310         case 'h':
 311                 *c_size = sizeof(short);
 312                 break;
 313         default:
 314                 *c_size = sizeof(int);
 315         }
 316
 317 parse_end:
 318         return fmt;
 319 }
 320
 321 static inline size_t serialize_trace_data(struct rchan_buf *buf,
 322                 size_t buf_offset,
 323                 char trace_size, enum ltt_type trace_type,
 324                 char c_size, enum ltt_type c_type,
 325                 int *largest_align, va_list *args)
 326 {
 327         union {
 328                 unsigned long v_ulong;
 329                 uint64_t v_uint64;
 330                 struct {
 331                         const char *s;
 332                         size_t len;
 333                 } v_string;
 334         } tmp;
 335
 336         /*
 337          * Be careful about sign extension here.
 338          * Sign extension is done with the destination (trace) type.
 339          */
 340         switch (trace_type) {
 341         case LTT_TYPE_SIGNED_INT:
 342                 switch (c_size) {
 343                 case 1:
 344                         tmp.v_ulong = (long)(int8_t)va_arg(*args, int);
 345                         break;
 346                 case 2:
 347                         tmp.v_ulong = (long)(int16_t)va_arg(*args, int);
 348                         break;
 349                 case 4:
 350                         tmp.v_ulong = (long)(int32_t)va_arg(*args, int);
 351                         break;
 352                 case 8:
 353                         tmp.v_uint64 = va_arg(*args, int64_t);
 354                         break;
 355                 default:
 356                         BUG();
 357                 }
 358                 break;
 359         case LTT_TYPE_UNSIGNED_INT:
 360                 switch (c_size) {
 361                 case 1:
 362                         tmp.v_ulong = (unsigned long)(uint8_t)
 363                                         va_arg(*args, unsigned int);
 364                         break;
 365                 case 2:
 366                         tmp.v_ulong = (unsigned long)(uint16_t)
 367                                         va_arg(*args, unsigned int);
 368                         break;
 369                 case 4:
 370                         tmp.v_ulong = (unsigned long)(uint32_t)
 371                                         va_arg(*args, unsigned int);
 372                         break;
 373                 case 8:
 374                         tmp.v_uint64 = va_arg(*args, uint64_t);
 375                         break;
 376                 default:
 377                         BUG();
 378                 }
 379                 break;
 380         case LTT_TYPE_STRING:
 381                 tmp.v_string.s = va_arg(*args, const char *);
 382                 if ((unsigned long)tmp.v_string.s < PAGE_SIZE)
 383                         tmp.v_string.s = "<NULL>";
 384                 tmp.v_string.len = strlen(tmp.v_string.s)+1;
 385                 if (buf)
 386                         ltt_relay_write(buf, buf_offset, tmp.v_string.s,
 387                                 tmp.v_string.len);
 388                 buf_offset += tmp.v_string.len;
 389                 goto copydone;
 390         default:
 391                 BUG();
 392         }
 393
 394         /*
 395          * If trace_size is lower or equal to 4 bytes, there is no sign
 396          * extension to do because we are already encoded in a long. Therefore,
 397          * we can combine signed and unsigned ops. 4 bytes float also works
 398          * with this, because we do a simple copy of 4 bytes into 4 bytes
 399          * without manipulation (and we do not support conversion from integers
 400          * to floats).
 401          * It is also the case if c_size is 8 bytes, which is the largest
 402          * possible integer.
 403          */
 404         if (ltt_get_alignment()) {
 405                 buf_offset += ltt_align(buf_offset, trace_size);
 406                 if (largest_align)
 407                         *largest_align = max_t(int, *largest_align, trace_size);
 408         }
 409         if (trace_size <= 4 || c_size == 8) {
 410                 if (buf) {
 411                         switch (trace_size) {
 412                         case 1:
 413                                 if (c_size == 8)
 414                                         ltt_relay_write(buf, buf_offset,
 415                                         (uint8_t[]){ (uint8_t)tmp.v_uint64 },
 416                                         sizeof(uint8_t));
 417                                 else
 418                                         ltt_relay_write(buf, buf_offset,
 419                                         (uint8_t[]){ (uint8_t)tmp.v_ulong },
 420                                         sizeof(uint8_t));
 421                                 break;
 422                         case 2:
 423                                 if (c_size == 8)
 424                                         ltt_relay_write(buf, buf_offset,
 425                                         (uint16_t[]){ (uint16_t)tmp.v_uint64 },
 426                                         sizeof(uint16_t));
 427                                 else
 428                                         ltt_relay_write(buf, buf_offset,
 429                                         (uint16_t[]){ (uint16_t)tmp.v_ulong },
 430                                         sizeof(uint16_t));
 431                                 break;
 432                         case 4:
 433                                 if (c_size == 8)
 434                                         ltt_relay_write(buf, buf_offset,
 435                                         (uint32_t[]){ (uint32_t)tmp.v_uint64 },
 436                                         sizeof(uint32_t));
 437                                 else
 438                                         ltt_relay_write(buf, buf_offset,
 439                                         (uint32_t[]){ (uint32_t)tmp.v_ulong },
 440                                         sizeof(uint32_t));
 441                                 break;
 442                         case 8:
 443                                 /*
 444                                  * c_size cannot be other than 8 here because
 445                                  * trace_size > 4.
 446                                  */
 447                                 ltt_relay_write(buf, buf_offset,
 448                                 (uint64_t[]){ (uint64_t)tmp.v_uint64 },
 449                                 sizeof(uint64_t));
 450                                 break;
 451                         default:
 452                                 BUG();
 453                         }
 454                 }
 455                 buf_offset += trace_size;
 456                 goto copydone;
 457         } else {
 458                 /*
 459                  * Perform sign extension.
 460                  */
 461                 if (buf) {
 462                         switch (trace_type) {
 463                         case LTT_TYPE_SIGNED_INT:
 464                                 ltt_relay_write(buf, buf_offset,
 465                                         (int64_t[]){ (int64_t)tmp.v_ulong },
 466                                         sizeof(int64_t));
 467                                 break;
 468                         case LTT_TYPE_UNSIGNED_INT:
 469                                 ltt_relay_write(buf, buf_offset,
 470                                         (uint64_t[]){ (uint64_t)tmp.v_ulong },
 471                                         sizeof(uint64_t));
 472                                 break;
 473                         default:
 474                                 BUG();
 475                         }
 476                 }
 477                 buf_offset += trace_size;
 478                 goto copydone;
 479         }
 480
 481 copydone:
 482         return buf_offset;
 483 }
 484
 485 notrace size_t ltt_serialize_data(struct rchan_buf *buf, size_t buf_offset,
 486                         struct ltt_serialize_closure *closure,
 487                         void *serialize_private, int *largest_align,
 488                         const char *fmt, va_list *args)
 489 {
 490         char trace_size = 0, c_size = 0;        /*
 491                                                  * 0 (unset), 1, 2, 4, 8 bytes.
 492                                                  */
 493         enum ltt_type trace_type = LTT_TYPE_NONE, c_type = LTT_TYPE_NONE;
 494         unsigned long attributes = 0;
 495
 496         for (; *fmt ; ++fmt) {
 497                 switch (*fmt) {
 498                 case '#':
 499                         /* tracetypes (#) */
 500                         ++fmt;                  /* skip first '#' */
 501                         if (*fmt == '#')        /* Escaped ## */
 502                                 break;
 503                         attributes = 0;
 504                         fmt = parse_trace_type(fmt, &trace_size, &trace_type,
 505                                 &attributes);
 506                         break;
 507                 case '%':
 508                         /* c types (%) */
 509                         ++fmt;                  /* skip first '%' */
 510                         if (*fmt == '%')        /* Escaped %% */
 511                                 break;
 512                         fmt = parse_c_type(fmt, &c_size, &c_type);
 513                         /*
 514                          * Output c types if no trace types has been
 515                          * specified.
 516                          */
 517                         if (!trace_size)
 518                                 trace_size = c_size;
 519                         if (trace_type == LTT_TYPE_NONE)
 520                                 trace_type = c_type;
 521                         if (c_type == LTT_TYPE_STRING)
 522                                 trace_type = LTT_TYPE_STRING;
 523                         /* perform trace write */
 524                         buf_offset = serialize_trace_data(buf,
 525                                                 buf_offset, trace_size,
 526                                                 trace_type, c_size, c_type,
 527                                                 largest_align, args);
 528                         trace_size = 0;
 529                         c_size = 0;
 530                         trace_type = LTT_TYPE_NONE;
 531                         c_size = LTT_TYPE_NONE;
 532                         attributes = 0;
 533                         break;
 534                         /* default is to skip the text, doing nothing */
 535                 }
 536         }
 537         return buf_offset;
 538 }
 539 EXPORT_SYMBOL_GPL(ltt_serialize_data);
 540
 541 /*
 542  * Calculate data size
 543  * Assume that the padding for alignment starts at a sizeof(void *) address.
 544  */
 545 static notrace size_t ltt_get_data_size(struct ltt_serialize_closure *closure,
 546                                 void *serialize_private, int *largest_align,
 547                                 const char *fmt, va_list *args)
 548 {
 549         ltt_serialize_cb cb = closure->callbacks[0];
 550         closure->cb_idx = 0;
 551         return (size_t)cb(NULL, 0, closure, serialize_private,
 552                                 largest_align, fmt, args);
 553 }
 554
 555 static notrace
 556 void ltt_write_event_data(struct rchan_buf *buf, size_t buf_offset,
 557                                 struct ltt_serialize_closure *closure,
 558                                 void *serialize_private, int largest_align,
 559                                 const char *fmt, va_list *args)
 560 {
 561         ltt_serialize_cb cb = closure->callbacks[0];
 562         closure->cb_idx = 0;
 563         buf_offset += ltt_align(buf_offset, largest_align);
 564         cb(buf, buf_offset, closure, serialize_private, NULL, fmt, args);
 565 }
 566
 567
 568 notrace void ltt_vtrace(const struct marker *mdata, void *probe_data,
 569                         void *call_data, const char *fmt, va_list *args)
 570 {
 571         int largest_align, ret;
 572         struct ltt_active_marker *pdata;
 573         uint16_t eID;
 574         size_t data_size, slot_size;
 575         unsigned int chan_index;
 576         struct ltt_channel_struct *channel;
 577         struct ltt_trace_struct *trace, *dest_trace = NULL;
 578         struct rchan_buf *buf;
 579         void *transport_data;
 580         u64 tsc;
 581         long buf_offset;
 582         va_list args_copy;
 583         struct ltt_serialize_closure closure;
 584         struct ltt_probe_private_data *private_data = call_data;
 585         void *serialize_private = NULL;
 586         int cpu;
 587         unsigned int rflags;
 588
 589         /*
 590          * This test is useful for quickly exiting static tracing when no trace
 591          * is active. We expect to have an active trace when we get here.
 592          */
 593         if (unlikely(ltt_traces.num_active_traces == 0))
 594                 return;
 595
 596         rcu_read_lock_sched_notrace();
 597         cpu = smp_processor_id();
 598 //ust// __get_cpu_var(ltt_nesting)++;
 599         ltt_nesting++;
 600
 601         pdata = (struct ltt_active_marker *)probe_data;
 602         eID = mdata->event_id;
 603         chan_index = mdata->channel_id;
 604         closure.callbacks = pdata->probe->callbacks;
 605
 606         if (unlikely(private_data)) {
 607                 dest_trace = private_data->trace;
 608                 if (private_data->serializer)
 609                         closure.callbacks = &private_data->serializer;
 610                 serialize_private = private_data->serialize_private;
 611         }
 612
 613         va_copy(args_copy, *args);
 614         /*
 615          * Assumes event payload to start on largest_align alignment.
 616          */
 617         largest_align = 1;      /* must be non-zero for ltt_align */
 618         data_size = ltt_get_data_size(&closure, serialize_private,
 619                                         &largest_align, fmt, &args_copy);
 620         largest_align = min_t(int, largest_align, sizeof(void *));
 621         va_end(args_copy);
 622
 623         /* Iterate on each trace */
 624         list_for_each_entry_rcu(trace, &ltt_traces.head, list) {
 625                 /*
 626                  * Expect the filter to filter out events. If we get here,
 627                  * we went through tracepoint activation as a first step.
 628                  */
 629                 if (unlikely(dest_trace && trace != dest_trace))
 630                         continue;
 631                 if (unlikely(!trace->active))
 632                         continue;
 633                 if (unlikely(!ltt_run_filter(trace, eID)))
 634                         continue;
 635 #ifdef CONFIG_LTT_DEBUG_EVENT_SIZE
 636                 rflags = LTT_RFLAG_ID_SIZE;
 637 #else
 638                 if (unlikely(eID >= LTT_FREE_EVENTS))
 639                         rflags = LTT_RFLAG_ID;
 640                 else
 641                         rflags = 0;
 642 #endif
 643                 /*
 644                  * Skip channels added after trace creation.
 645                  */
 646                 if (unlikely(chan_index >= trace->nr_channels))
 647                         continue;
 648                 channel = &trace->channels[chan_index];
 649                 if (!channel->active)
 650                         continue;
 651
 652                 /* reserve space : header and data */
 653                 ret = ltt_reserve_slot(trace, channel, &transport_data,
 654                                         data_size, &slot_size, &buf_offset,
 655                                         &tsc, &rflags,
 656                                         largest_align);
 657                 if (unlikely(ret < 0))
 658                         continue; /* buffer full */
 659
 660                 va_copy(args_copy, *args);
 661                 /* FIXME : could probably encapsulate transport better. */
 662 //ust//         buf = ((struct rchan *)channel->trans_channel_data)->buf[cpu];
 663                 buf = ((struct rchan *)channel->trans_channel_data)->buf;
 664                 /* Out-of-order write : header and data */
 665                 buf_offset = ltt_write_event_header(trace,
 666                                         channel, buf, buf_offset,
 667                                         eID, data_size, tsc, rflags);
 668                 ltt_write_event_data(buf, buf_offset, &closure,
 669                                         serialize_private,
 670                                         largest_align, fmt, &args_copy);
 671                 va_end(args_copy);
 672                 /* Out-of-order commit */
 673                 ltt_commit_slot(channel, &transport_data, buf_offset,
 674                                 slot_size);
 675                 printf("just commited event at offset %d and size %d\n", buf_offset, slot_size);
 676         }
 677 //ust// __get_cpu_var(ltt_nesting)--;
 678         ltt_nesting--;
 679         rcu_read_unlock_sched_notrace();
 680 }
 681 EXPORT_SYMBOL_GPL(ltt_vtrace);
 682
 683 notrace void ltt_trace(const struct marker *mdata, void *probe_data,
 684                        void *call_data, const char *fmt, ...)
 685 {
 686         va_list args;
 687
 688         va_start(args, fmt);
 689         ltt_vtrace(mdata, probe_data, call_data, fmt, &args);
 690         va_end(args);
 691 }
 692 EXPORT_SYMBOL_GPL(ltt_trace);
 693
 694 //ust// MODULE_LICENSE("GPL");
 695 //ust// MODULE_AUTHOR("Mathieu Desnoyers");
 696 //ust// MODULE_DESCRIPTION("Linux Trace Toolkit Next Generation Serializer");